readahead: disable collector automatically on read-only media

[thirdparty/systemd.git] / src / util.c

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <syslog.h>
#include <sched.h>
#include <sys/resource.h>
#include <linux/sched.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/ioctl.h>
#include <linux/vt.h>
#include <linux/tiocl.h>
#include <termios.h>
#include <stdarg.h>
#include <sys/inotify.h>
#include <sys/poll.h>
#include <libgen.h>
#include <ctype.h>
#include <sys/prctl.h>
#include <sys/utsname.h>
#include <pwd.h>
#include <netinet/ip.h>
#include <linux/kd.h>
#include <dlfcn.h>
#include <sys/wait.h>

#include "macro.h"
#include "util.h"
#include "ioprio.h"
#include "missing.h"
#include "log.h"
#include "strv.h"
#include "label.h"
#include "exit-status.h"
#include "hashmap.h"

bool streq_ptr(const char *a, const char *b) {

        /* Like streq(), but tries to make sense of NULL pointers */

        if (a && b)
                return streq(a, b);

        if (!a && !b)
                return true;

        return false;
}

usec_t now(clockid_t clock_id) {
        struct timespec ts;

        assert_se(clock_gettime(clock_id, &ts) == 0);

        return timespec_load(&ts);
}

dual_timestamp* dual_timestamp_get(dual_timestamp *ts) {
        assert(ts);

        ts->realtime = now(CLOCK_REALTIME);
        ts->monotonic = now(CLOCK_MONOTONIC);

        return ts;
}

usec_t timespec_load(const struct timespec *ts) {
        assert(ts);

        return
                (usec_t) ts->tv_sec * USEC_PER_SEC +
                (usec_t) ts->tv_nsec / NSEC_PER_USEC;
}

struct timespec *timespec_store(struct timespec *ts, usec_t u)  {
        assert(ts);

        ts->tv_sec = (time_t) (u / USEC_PER_SEC);
        ts->tv_nsec = (long int) ((u % USEC_PER_SEC) * NSEC_PER_USEC);

        return ts;
}

usec_t timeval_load(const struct timeval *tv) {
        assert(tv);

        return
                (usec_t) tv->tv_sec * USEC_PER_SEC +
                (usec_t) tv->tv_usec;
}

struct timeval *timeval_store(struct timeval *tv, usec_t u) {
        assert(tv);

        tv->tv_sec = (time_t) (u / USEC_PER_SEC);
        tv->tv_usec = (suseconds_t) (u % USEC_PER_SEC);

        return tv;
}

bool endswith(const char *s, const char *postfix) {
        size_t sl, pl;

        assert(s);
        assert(postfix);

        sl = strlen(s);
        pl = strlen(postfix);

        if (pl == 0)
                return true;

        if (sl < pl)
                return false;

        return memcmp(s + sl - pl, postfix, pl) == 0;
}

bool startswith(const char *s, const char *prefix) {
        size_t sl, pl;

        assert(s);
        assert(prefix);

        sl = strlen(s);
        pl = strlen(prefix);

        if (pl == 0)
                return true;

        if (sl < pl)
                return false;

        return memcmp(s, prefix, pl) == 0;
}

bool startswith_no_case(const char *s, const char *prefix) {
        size_t sl, pl;
        unsigned i;

        assert(s);
        assert(prefix);

        sl = strlen(s);
        pl = strlen(prefix);

        if (pl == 0)
                return true;

        if (sl < pl)
                return false;

        for(i = 0; i < pl; ++i) {
                if (tolower(s[i]) != tolower(prefix[i]))
                        return false;
        }

        return true;
}

bool first_word(const char *s, const char *word) {
        size_t sl, wl;

        assert(s);
        assert(word);

        sl = strlen(s);
        wl = strlen(word);

        if (sl < wl)
                return false;

        if (wl == 0)
                return true;

        if (memcmp(s, word, wl) != 0)
                return false;

        return s[wl] == 0 ||
                strchr(WHITESPACE, s[wl]);
}

int close_nointr(int fd) {
        assert(fd >= 0);

        for (;;) {
                int r;

                if ((r = close(fd)) >= 0)
                        return r;

                if (errno != EINTR)
                        return r;
        }
}

void close_nointr_nofail(int fd) {
        int saved_errno = errno;

        /* like close_nointr() but cannot fail, and guarantees errno
         * is unchanged */

        assert_se(close_nointr(fd) == 0);

        errno = saved_errno;
}

void close_many(const int fds[], unsigned n_fd) {
        unsigned i;

        for (i = 0; i < n_fd; i++)
                close_nointr_nofail(fds[i]);
}

int parse_boolean(const char *v) {
        assert(v);

        if (streq(v, "1") || v[0] == 'y' || v[0] == 'Y' || v[0] == 't' || v[0] == 'T' || !strcasecmp(v, "on"))
                return 1;
        else if (streq(v, "0") || v[0] == 'n' || v[0] == 'N' || v[0] == 'f' || v[0] == 'F' || !strcasecmp(v, "off"))
                return 0;

        return -EINVAL;
}

int parse_pid(const char *s, pid_t* ret_pid) {
        unsigned long ul = 0;
        pid_t pid;
        int r;

        assert(s);
        assert(ret_pid);

        if ((r = safe_atolu(s, &ul)) < 0)
                return r;

        pid = (pid_t) ul;

        if ((unsigned long) pid != ul)
                return -ERANGE;

        if (pid <= 0)
                return -ERANGE;

        *ret_pid = pid;
        return 0;
}

int safe_atou(const char *s, unsigned *ret_u) {
        char *x = NULL;
        unsigned long l;

        assert(s);
        assert(ret_u);

        errno = 0;
        l = strtoul(s, &x, 0);

        if (!x || *x || errno)
                return errno ? -errno : -EINVAL;

        if ((unsigned long) (unsigned) l != l)
                return -ERANGE;

        *ret_u = (unsigned) l;
        return 0;
}

int safe_atoi(const char *s, int *ret_i) {
        char *x = NULL;
        long l;

        assert(s);
        assert(ret_i);

        errno = 0;
        l = strtol(s, &x, 0);

        if (!x || *x || errno)
                return errno ? -errno : -EINVAL;

        if ((long) (int) l != l)
                return -ERANGE;

        *ret_i = (int) l;
        return 0;
}

int safe_atollu(const char *s, long long unsigned *ret_llu) {
        char *x = NULL;
        unsigned long long l;

        assert(s);
        assert(ret_llu);

        errno = 0;
        l = strtoull(s, &x, 0);

        if (!x || *x || errno)
                return errno ? -errno : -EINVAL;

        *ret_llu = l;
        return 0;
}

int safe_atolli(const char *s, long long int *ret_lli) {
        char *x = NULL;
        long long l;

        assert(s);
        assert(ret_lli);

        errno = 0;
        l = strtoll(s, &x, 0);

        if (!x || *x || errno)
                return errno ? -errno : -EINVAL;

        *ret_lli = l;
        return 0;
}

/* Split a string into words. */
char *split(const char *c, size_t *l, const char *separator, char **state) {
        char *current;

        current = *state ? *state : (char*) c;

        if (!*current || *c == 0)
                return NULL;

        current += strspn(current, separator);
        *l = strcspn(current, separator);
        *state = current+*l;

        return (char*) current;
}

/* Split a string into words, but consider strings enclosed in '' and
 * "" as words even if they include spaces. */
char *split_quoted(const char *c, size_t *l, char **state) {
        char *current, *e;
        bool escaped = false;

        current = *state ? *state : (char*) c;

        if (!*current || *c == 0)
                return NULL;

        current += strspn(current, WHITESPACE);

        if (*current == '\'') {
                current ++;

                for (e = current; *e; e++) {
                        if (escaped)
                                escaped = false;
                        else if (*e == '\\')
                                escaped = true;
                        else if (*e == '\'')
                                break;
                }

                *l = e-current;
                *state = *e == 0 ? e : e+1;
        } else if (*current == '\"') {
                current ++;

                for (e = current; *e; e++) {
                        if (escaped)
                                escaped = false;
                        else if (*e == '\\')
                                escaped = true;
                        else if (*e == '\"')
                                break;
                }

                *l = e-current;
                *state = *e == 0 ? e : e+1;
        } else {
                for (e = current; *e; e++) {
                        if (escaped)
                                escaped = false;
                        else if (*e == '\\')
                                escaped = true;
                        else if (strchr(WHITESPACE, *e))
                                break;
                }
                *l = e-current;
                *state = e;
        }

        return (char*) current;
}

char **split_path_and_make_absolute(const char *p) {
        char **l;
        assert(p);

        if (!(l = strv_split(p, ":")))
                return NULL;

        if (!strv_path_make_absolute_cwd(l)) {
                strv_free(l);
                return NULL;
        }

        return l;
}

int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
        int r;
        FILE *f;
        char fn[132], line[256], *p;
        long unsigned ppid;

        assert(pid >= 0);
        assert(_ppid);

        assert_se(snprintf(fn, sizeof(fn)-1, "/proc/%lu/stat", (unsigned long) pid) < (int) (sizeof(fn)-1));
        fn[sizeof(fn)-1] = 0;

        if (!(f = fopen(fn, "r")))
                return -errno;

        if (!(fgets(line, sizeof(line), f))) {
                r = -errno;
                fclose(f);
                return r;
        }

        fclose(f);

        /* Let's skip the pid and comm fields. The latter is enclosed
         * in () but does not escape any () in its value, so let's
         * skip over it manually */

        if (!(p = strrchr(line, ')')))
                return -EIO;

        p++;

        if (sscanf(p, " "
                   "%*c "  /* state */
                   "%lu ", /* ppid */
                   &ppid) != 1)
                return -EIO;

        if ((long unsigned) (pid_t) ppid != ppid)
                return -ERANGE;

        *_ppid = (pid_t) ppid;

        return 0;
}

int write_one_line_file(const char *fn, const char *line) {
        FILE *f;
        int r;

        assert(fn);
        assert(line);

        if (!(f = fopen(fn, "we")))
                return -errno;

        if (fputs(line, f) < 0) {
                r = -errno;
                goto finish;
        }

        if (!endswith(line, "\n"))
                fputc('\n', f);

        r = 0;
finish:
        fclose(f);
        return r;
}

int read_one_line_file(const char *fn, char **line) {
        FILE *f;
        int r;
        char t[LINE_MAX], *c;

        assert(fn);
        assert(line);

        if (!(f = fopen(fn, "re")))
                return -errno;

        if (!(fgets(t, sizeof(t), f))) {
                r = -errno;
                goto finish;
        }

        if (!(c = strdup(t))) {
                r = -ENOMEM;
                goto finish;
        }

        *line = c;
        r = 0;

finish:
        fclose(f);
        return r;
}

int read_full_file(const char *fn, char **contents) {
        FILE *f;
        int r;
        size_t n, l;
        char *buf = NULL;
        struct stat st;

        if (!(f = fopen(fn, "re")))
                return -errno;

        if (fstat(fileno(f), &st) < 0) {
                r = -errno;
                goto finish;
        }

        n = st.st_size > 0 ? st.st_size : LINE_MAX;
        l = 0;

        for (;;) {
                char *t;
                size_t k;

                if (!(t = realloc(buf, n+1))) {
                        r = -ENOMEM;
                        goto finish;
                }

                buf = t;
                k = fread(buf + l, 1, n - l, f);

                if (k <= 0) {
                        if (ferror(f)) {
                                r = -errno;
                                goto finish;
                        }

                        break;
                }

                l += k;
                n *= 2;

                /* Safety check */
                if (n > 4*1024*1024) {
                        r = -E2BIG;
                        goto finish;
                }
        }

        if (buf)
                buf[l] = 0;
        else if (!(buf = calloc(1, 1))) {
                r = -errno;
                goto finish;
        }

        *contents = buf;
        buf = NULL;

        r = 0;

finish:
        fclose(f);
        free(buf);

        return r;
}

int parse_env_file(
                const char *fname,
                const char *separator, ...) {

        int r = 0;
        char *contents, *p;

        assert(fname);
        assert(separator);

        if ((r = read_full_file(fname, &contents)) < 0)
                return r;

        p = contents;
        for (;;) {
                const char *key = NULL;

                p += strspn(p, separator);
                p += strspn(p, WHITESPACE);

                if (!*p)
                        break;

                if (!strchr(COMMENTS, *p)) {
                        va_list ap;
                        char **value;

                        va_start(ap, separator);
                        while ((key = va_arg(ap, char *))) {
                                size_t n;
                                char *v;

                                value = va_arg(ap, char **);

                                n = strlen(key);
                                if (strncmp(p, key, n) != 0 ||
                                    p[n] != '=')
                                        continue;

                                p += n + 1;
                                n = strcspn(p, separator);

                                if (n >= 2 &&
                                    strchr(QUOTES, p[0]) &&
                                    p[n-1] == p[0])
                                        v = strndup(p+1, n-2);
                                else
                                        v = strndup(p, n);

                                if (!v) {
                                        r = -ENOMEM;
                                        va_end(ap);
                                        goto fail;
                                }

                                if (v[0] == '\0') {
                                        /* return empty value strings as NULL */
                                        free(v);
                                        v = NULL;
                                }

                                free(*value);
                                *value = v;

                                p += n;

                                r ++;
                                break;
                        }
                        va_end(ap);
                }

                if (!key)
                        p += strcspn(p, separator);
        }

fail:
        free(contents);
        return r;
}

char *truncate_nl(char *s) {
        assert(s);

        s[strcspn(s, NEWLINE)] = 0;
        return s;
}

int get_process_name(pid_t pid, char **name) {
        char *p;
        int r;

        assert(pid >= 1);
        assert(name);

        if (asprintf(&p, "/proc/%lu/comm", (unsigned long) pid) < 0)
                return -ENOMEM;

        r = read_one_line_file(p, name);
        free(p);

        if (r < 0)
                return r;

        truncate_nl(*name);
        return 0;
}

int get_process_cmdline(pid_t pid, size_t max_length, char **line) {
        char *p, *r, *k;
        int c;
        bool space = false;
        size_t left;
        FILE *f;

        assert(pid >= 1);
        assert(max_length > 0);
        assert(line);

        if (asprintf(&p, "/proc/%lu/cmdline", (unsigned long) pid) < 0)
                return -ENOMEM;

        f = fopen(p, "r");
        free(p);

        if (!f)
                return -errno;

        if (!(r = new(char, max_length))) {
                fclose(f);
                return -ENOMEM;
        }

        k = r;
        left = max_length;
        while ((c = getc(f)) != EOF) {

                if (isprint(c)) {
                        if (space) {
                                if (left <= 4)
                                        break;

                                *(k++) = ' ';
                                left--;
                                space = false;
                        }

                        if (left <= 4)
                                break;

                        *(k++) = (char) c;
                        left--;
                }  else
                        space = true;
        }

        if (left <= 4) {
                size_t n = MIN(left-1, 3U);
                memcpy(k, "...", n);
                k[n] = 0;
        } else
                *k = 0;

        fclose(f);

        /* Kernel threads have no argv[] */
        if (r[0] == 0) {
                char *t;
                int h;

                free(r);

                if ((h = get_process_name(pid, &t)) < 0)
                        return h;

                h = asprintf(&r, "[%s]", t);
                free(t);

                if (h < 0)
                        return -ENOMEM;
        }

        *line = r;
        return 0;
}

char *strnappend(const char *s, const char *suffix, size_t b) {
        size_t a;
        char *r;

        if (!s && !suffix)
                return strdup("");

        if (!s)
                return strndup(suffix, b);

        if (!suffix)
                return strdup(s);

        assert(s);
        assert(suffix);

        a = strlen(s);

        if (!(r = new(char, a+b+1)))
                return NULL;

        memcpy(r, s, a);
        memcpy(r+a, suffix, b);
        r[a+b] = 0;

        return r;
}

char *strappend(const char *s, const char *suffix) {
        return strnappend(s, suffix, suffix ? strlen(suffix) : 0);
}

int readlink_malloc(const char *p, char **r) {
        size_t l = 100;

        assert(p);
        assert(r);

        for (;;) {
                char *c;
                ssize_t n;

                if (!(c = new(char, l)))
                        return -ENOMEM;

                if ((n = readlink(p, c, l-1)) < 0) {
                        int ret = -errno;
                        free(c);
                        return ret;
                }

                if ((size_t) n < l-1) {
                        c[n] = 0;
                        *r = c;
                        return 0;
                }

                free(c);
                l *= 2;
        }
}

int readlink_and_make_absolute(const char *p, char **r) {
        char *target, *k;
        int j;

        assert(p);
        assert(r);

        if ((j = readlink_malloc(p, &target)) < 0)
                return j;

        k = file_in_same_dir(p, target);
        free(target);

        if (!k)
                return -ENOMEM;

        *r = k;
        return 0;
}

int parent_of_path(const char *path, char **_r) {
        const char *e, *a = NULL, *b = NULL, *p;
        char *r;
        bool slash = false;

        assert(path);
        assert(_r);

        if (!*path)
                return -EINVAL;

        for (e = path; *e; e++) {

                if (!slash && *e == '/') {
                        a = b;
                        b = e;
                        slash = true;
                } else if (slash && *e != '/')
                        slash = false;
        }

        if (*(e-1) == '/')
                p = a;
        else
                p = b;

        if (!p)
                return -EINVAL;

        if (p == path)
                r = strdup("/");
        else
                r = strndup(path, p-path);

        if (!r)
                return -ENOMEM;

        *_r = r;
        return 0;
}


char *file_name_from_path(const char *p) {
        char *r;

        assert(p);

        if ((r = strrchr(p, '/')))
                return r + 1;

        return (char*) p;
}

bool path_is_absolute(const char *p) {
        assert(p);

        return p[0] == '/';
}

bool is_path(const char *p) {

        return !!strchr(p, '/');
}

char *path_make_absolute(const char *p, const char *prefix) {
        char *r;

        assert(p);

        /* Makes every item in the list an absolute path by prepending
         * the prefix, if specified and necessary */

        if (path_is_absolute(p) || !prefix)
                return strdup(p);

        if (asprintf(&r, "%s/%s", prefix, p) < 0)
                return NULL;

        return r;
}

char *path_make_absolute_cwd(const char *p) {
        char *cwd, *r;

        assert(p);

        /* Similar to path_make_absolute(), but prefixes with the
         * current working directory. */

        if (path_is_absolute(p))
                return strdup(p);

        if (!(cwd = get_current_dir_name()))
                return NULL;

        r = path_make_absolute(p, cwd);
        free(cwd);

        return r;
}

char **strv_path_make_absolute_cwd(char **l) {
        char **s;

        /* Goes through every item in the string list and makes it
         * absolute. This works in place and won't rollback any
         * changes on failure. */

        STRV_FOREACH(s, l) {
                char *t;

                if (!(t = path_make_absolute_cwd(*s)))
                        return NULL;

                free(*s);
                *s = t;
        }

        return l;
}

char **strv_path_canonicalize(char **l) {
        char **s;
        unsigned k = 0;
        bool enomem = false;

        if (strv_isempty(l))
                return l;

        /* Goes through every item in the string list and canonicalize
         * the path. This works in place and won't rollback any
         * changes on failure. */

        STRV_FOREACH(s, l) {
                char *t, *u;

                t = path_make_absolute_cwd(*s);
                free(*s);

                if (!t) {
                        enomem = true;
                        continue;
                }

                errno = 0;
                u = canonicalize_file_name(t);
                free(t);

                if (!u) {
                        if (errno == ENOMEM || !errno)
                                enomem = true;

                        continue;
                }

                l[k++] = u;
        }

        l[k] = NULL;

        if (enomem)
                return NULL;

        return l;
}

int reset_all_signal_handlers(void) {
        int sig;

        for (sig = 1; sig < _NSIG; sig++) {
                struct sigaction sa;

                if (sig == SIGKILL || sig == SIGSTOP)
                        continue;

                zero(sa);
                sa.sa_handler = SIG_DFL;
                sa.sa_flags = SA_RESTART;

                /* On Linux the first two RT signals are reserved by
                 * glibc, and sigaction() will return EINVAL for them. */
                if ((sigaction(sig, &sa, NULL) < 0))
                        if (errno != EINVAL)
                                return -errno;
        }

        return 0;
}

char *strstrip(char *s) {
        char *e, *l = NULL;

        /* Drops trailing whitespace. Modifies the string in
         * place. Returns pointer to first non-space character */

        s += strspn(s, WHITESPACE);

        for (e = s; *e; e++)
                if (!strchr(WHITESPACE, *e))
                        l = e;

        if (l)
                *(l+1) = 0;
        else
                *s = 0;

        return s;
}

char *delete_chars(char *s, const char *bad) {
        char *f, *t;

        /* Drops all whitespace, regardless where in the string */

        for (f = s, t = s; *f; f++) {
                if (strchr(bad, *f))
                        continue;

                *(t++) = *f;
        }

        *t = 0;

        return s;
}

char *file_in_same_dir(const char *path, const char *filename) {
        char *e, *r;
        size_t k;

        assert(path);
        assert(filename);

        /* This removes the last component of path and appends
         * filename, unless the latter is absolute anyway or the
         * former isn't */

        if (path_is_absolute(filename))
                return strdup(filename);

        if (!(e = strrchr(path, '/')))
                return strdup(filename);

        k = strlen(filename);
        if (!(r = new(char, e-path+1+k+1)))
                return NULL;

        memcpy(r, path, e-path+1);
        memcpy(r+(e-path)+1, filename, k+1);

        return r;
}

int safe_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid) {
        struct stat st;

        if (label_mkdir(path, mode) >= 0)
                if (chmod_and_chown(path, mode, uid, gid) < 0)
                        return -errno;

        if (lstat(path, &st) < 0)
                return -errno;

        if ((st.st_mode & 0777) != mode ||
            st.st_uid != uid ||
            st.st_gid != gid ||
            !S_ISDIR(st.st_mode)) {
                errno = EEXIST;
                return -errno;
        }

        return 0;
}


int mkdir_parents(const char *path, mode_t mode) {
        const char *p, *e;

        assert(path);

        /* Creates every parent directory in the path except the last
         * component. */

        p = path + strspn(path, "/");
        for (;;) {
                int r;
                char *t;

                e = p + strcspn(p, "/");
                p = e + strspn(e, "/");

                /* Is this the last component? If so, then we're
                 * done */
                if (*p == 0)
                        return 0;

                if (!(t = strndup(path, e - path)))
                        return -ENOMEM;

                r = label_mkdir(t, mode);
                free(t);

                if (r < 0 && errno != EEXIST)
                        return -errno;
        }
}

int mkdir_p(const char *path, mode_t mode) {
        int r;

        /* Like mkdir -p */

        if ((r = mkdir_parents(path, mode)) < 0)
                return r;

        if (label_mkdir(path, mode) < 0 && errno != EEXIST)
                return -errno;

        return 0;
}

int rmdir_parents(const char *path, const char *stop) {
        size_t l;
        int r = 0;

        assert(path);
        assert(stop);

        l = strlen(path);

        /* Skip trailing slashes */
        while (l > 0 && path[l-1] == '/')
                l--;

        while (l > 0) {
                char *t;

                /* Skip last component */
                while (l > 0 && path[l-1] != '/')
                        l--;

                /* Skip trailing slashes */
                while (l > 0 && path[l-1] == '/')
                        l--;

                if (l <= 0)
                        break;

                if (!(t = strndup(path, l)))
                        return -ENOMEM;

                if (path_startswith(stop, t)) {
                        free(t);
                        return 0;
                }

                r = rmdir(t);
                free(t);

                if (r < 0)
                        if (errno != ENOENT)
                                return -errno;
        }

        return 0;
}


char hexchar(int x) {
        static const char table[16] = "0123456789abcdef";

        return table[x & 15];
}

int unhexchar(char c) {

        if (c >= '0' && c <= '9')
                return c - '0';

        if (c >= 'a' && c <= 'f')
                return c - 'a' + 10;

        if (c >= 'A' && c <= 'F')
                return c - 'A' + 10;

        return -1;
}

char octchar(int x) {
        return '0' + (x & 7);
}

int unoctchar(char c) {

        if (c >= '0' && c <= '7')
                return c - '0';

        return -1;
}

char decchar(int x) {
        return '0' + (x % 10);
}

int undecchar(char c) {

        if (c >= '0' && c <= '9')
                return c - '0';

        return -1;
}

char *cescape(const char *s) {
        char *r, *t;
        const char *f;

        assert(s);

        /* Does C style string escaping. */

        if (!(r = new(char, strlen(s)*4 + 1)))
                return NULL;

        for (f = s, t = r; *f; f++)

                switch (*f) {

                case '\a':
                        *(t++) = '\\';
                        *(t++) = 'a';
                        break;
                case '\b':
                        *(t++) = '\\';
                        *(t++) = 'b';
                        break;
                case '\f':
                        *(t++) = '\\';
                        *(t++) = 'f';
                        break;
                case '\n':
                        *(t++) = '\\';
                        *(t++) = 'n';
                        break;
                case '\r':
                        *(t++) = '\\';
                        *(t++) = 'r';
                        break;
                case '\t':
                        *(t++) = '\\';
                        *(t++) = 't';
                        break;
                case '\v':
                        *(t++) = '\\';
                        *(t++) = 'v';
                        break;
                case '\\':
                        *(t++) = '\\';
                        *(t++) = '\\';
                        break;
                case '"':
                        *(t++) = '\\';
                        *(t++) = '"';
                        break;
                case '\'':
                        *(t++) = '\\';
                        *(t++) = '\'';
                        break;

                default:
                        /* For special chars we prefer octal over
                         * hexadecimal encoding, simply because glib's
                         * g_strescape() does the same */
                        if ((*f < ' ') || (*f >= 127)) {
                                *(t++) = '\\';
                                *(t++) = octchar((unsigned char) *f >> 6);
                                *(t++) = octchar((unsigned char) *f >> 3);
                                *(t++) = octchar((unsigned char) *f);
                        } else
                                *(t++) = *f;
                        break;
                }

        *t = 0;

        return r;
}

char *cunescape_length(const char *s, size_t length) {
        char *r, *t;
        const char *f;

        assert(s);

        /* Undoes C style string escaping */

        if (!(r = new(char, length+1)))
                return r;

        for (f = s, t = r; f < s + length; f++) {

                if (*f != '\\') {
                        *(t++) = *f;
                        continue;
                }

                f++;

                switch (*f) {

                case 'a':
                        *(t++) = '\a';
                        break;
                case 'b':
                        *(t++) = '\b';
                        break;
                case 'f':
                        *(t++) = '\f';
                        break;
                case 'n':
                        *(t++) = '\n';
                        break;
                case 'r':
                        *(t++) = '\r';
                        break;
                case 't':
                        *(t++) = '\t';
                        break;
                case 'v':
                        *(t++) = '\v';
                        break;
                case '\\':
                        *(t++) = '\\';
                        break;
                case '"':
                        *(t++) = '"';
                        break;
                case '\'':
                        *(t++) = '\'';
                        break;

                case 's':
                        /* This is an extension of the XDG syntax files */
                        *(t++) = ' ';
                        break;

                case 'x': {
                        /* hexadecimal encoding */
                        int a, b;

                        if ((a = unhexchar(f[1])) < 0 ||
                            (b = unhexchar(f[2])) < 0) {
                                /* Invalid escape code, let's take it literal then */
                                *(t++) = '\\';
                                *(t++) = 'x';
                        } else {
                                *(t++) = (char) ((a << 4) | b);
                                f += 2;
                        }

                        break;
                }

                case '0':
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7': {
                        /* octal encoding */
                        int a, b, c;

                        if ((a = unoctchar(f[0])) < 0 ||
                            (b = unoctchar(f[1])) < 0 ||
                            (c = unoctchar(f[2])) < 0) {
                                /* Invalid escape code, let's take it literal then */
                                *(t++) = '\\';
                                *(t++) = f[0];
                        } else {
                                *(t++) = (char) ((a << 6) | (b << 3) | c);
                                f += 2;
                        }

                        break;
                }

                case 0:
                        /* premature end of string.*/
                        *(t++) = '\\';
                        goto finish;

                default:
                        /* Invalid escape code, let's take it literal then */
                        *(t++) = '\\';
                        *(t++) = *f;
                        break;
                }
        }

finish:
        *t = 0;
        return r;
}

char *cunescape(const char *s) {
        return cunescape_length(s, strlen(s));
}

char *xescape(const char *s, const char *bad) {
        char *r, *t;
        const char *f;

        /* Escapes all chars in bad, in addition to \ and all special
         * chars, in \xFF style escaping. May be reversed with
         * cunescape. */

        if (!(r = new(char, strlen(s)*4+1)))
                return NULL;

        for (f = s, t = r; *f; f++) {

                if ((*f < ' ') || (*f >= 127) ||
                    (*f == '\\') || strchr(bad, *f)) {
                        *(t++) = '\\';
                        *(t++) = 'x';
                        *(t++) = hexchar(*f >> 4);
                        *(t++) = hexchar(*f);
                } else
                        *(t++) = *f;
        }

        *t = 0;

        return r;
}

char *bus_path_escape(const char *s) {
        char *r, *t;
        const char *f;

        assert(s);

        /* Escapes all chars that D-Bus' object path cannot deal
         * with. Can be reverse with bus_path_unescape() */

        if (!(r = new(char, strlen(s)*3+1)))
                return NULL;

        for (f = s, t = r; *f; f++) {

                if (!(*f >= 'A' && *f <= 'Z') &&
                    !(*f >= 'a' && *f <= 'z') &&
                    !(*f >= '0' && *f <= '9')) {
                        *(t++) = '_';
                        *(t++) = hexchar(*f >> 4);
                        *(t++) = hexchar(*f);
                } else
                        *(t++) = *f;
        }

        *t = 0;

        return r;
}

char *bus_path_unescape(const char *f) {
        char *r, *t;

        assert(f);

        if (!(r = strdup(f)))
                return NULL;

        for (t = r; *f; f++) {

                if (*f == '_') {
                        int a, b;

                        if ((a = unhexchar(f[1])) < 0 ||
                            (b = unhexchar(f[2])) < 0) {
                                /* Invalid escape code, let's take it literal then */
                                *(t++) = '_';
                        } else {
                                *(t++) = (char) ((a << 4) | b);
                                f += 2;
                        }
                } else
                        *(t++) = *f;
        }

        *t = 0;

        return r;
}

char *path_kill_slashes(char *path) {
        char *f, *t;
        bool slash = false;

        /* Removes redundant inner and trailing slashes. Modifies the
         * passed string in-place.
         *
         * ///foo///bar/ becomes /foo/bar
         */

        for (f = path, t = path; *f; f++) {

                if (*f == '/') {
                        slash = true;
                        continue;
                }

                if (slash) {
                        slash = false;
                        *(t++) = '/';
                }

                *(t++) = *f;
        }

        /* Special rule, if we are talking of the root directory, a
        trailing slash is good */

        if (t == path && slash)
                *(t++) = '/';

        *t = 0;
        return path;
}

bool path_startswith(const char *path, const char *prefix) {
        assert(path);
        assert(prefix);

        if ((path[0] == '/') != (prefix[0] == '/'))
                return false;

        for (;;) {
                size_t a, b;

                path += strspn(path, "/");
                prefix += strspn(prefix, "/");

                if (*prefix == 0)
                        return true;

                if (*path == 0)
                        return false;

                a = strcspn(path, "/");
                b = strcspn(prefix, "/");

                if (a != b)
                        return false;

                if (memcmp(path, prefix, a) != 0)
                        return false;

                path += a;
                prefix += b;
        }
}

bool path_equal(const char *a, const char *b) {
        assert(a);
        assert(b);

        if ((a[0] == '/') != (b[0] == '/'))
                return false;

        for (;;) {
                size_t j, k;

                a += strspn(a, "/");
                b += strspn(b, "/");

                if (*a == 0 && *b == 0)
                        return true;

                if (*a == 0 || *b == 0)
                        return false;

                j = strcspn(a, "/");
                k = strcspn(b, "/");

                if (j != k)
                        return false;

                if (memcmp(a, b, j) != 0)
                        return false;

                a += j;
                b += k;
        }
}

char *ascii_strlower(char *t) {
        char *p;

        assert(t);

        for (p = t; *p; p++)
                if (*p >= 'A' && *p <= 'Z')
                        *p = *p - 'A' + 'a';

        return t;
}

bool ignore_file(const char *filename) {
        assert(filename);

        return
                filename[0] == '.' ||
                streq(filename, "lost+found") ||
                streq(filename, "aquota.user") ||
                streq(filename, "aquota.group") ||
                endswith(filename, "~") ||
                endswith(filename, ".rpmnew") ||
                endswith(filename, ".rpmsave") ||
                endswith(filename, ".rpmorig") ||
                endswith(filename, ".dpkg-old") ||
                endswith(filename, ".dpkg-new") ||
                endswith(filename, ".swp");
}

int fd_nonblock(int fd, bool nonblock) {
        int flags;

        assert(fd >= 0);

        if ((flags = fcntl(fd, F_GETFL, 0)) < 0)
                return -errno;

        if (nonblock)
                flags |= O_NONBLOCK;
        else
                flags &= ~O_NONBLOCK;

        if (fcntl(fd, F_SETFL, flags) < 0)
                return -errno;

        return 0;
}

int fd_cloexec(int fd, bool cloexec) {
        int flags;

        assert(fd >= 0);

        if ((flags = fcntl(fd, F_GETFD, 0)) < 0)
                return -errno;

        if (cloexec)
                flags |= FD_CLOEXEC;
        else
                flags &= ~FD_CLOEXEC;

        if (fcntl(fd, F_SETFD, flags) < 0)
                return -errno;

        return 0;
}

int close_all_fds(const int except[], unsigned n_except) {
        DIR *d;
        struct dirent *de;
        int r = 0;

        if (!(d = opendir("/proc/self/fd")))
                return -errno;

        while ((de = readdir(d))) {
                int fd = -1;

                if (ignore_file(de->d_name))
                        continue;

                if ((r = safe_atoi(de->d_name, &fd)) < 0)
                        goto finish;

                if (fd < 3)
                        continue;

                if (fd == dirfd(d))
                        continue;

                if (except) {
                        bool found;
                        unsigned i;

                        found = false;
                        for (i = 0; i < n_except; i++)
                                if (except[i] == fd) {
                                        found = true;
                                        break;
                                }

                        if (found)
                                continue;
                }

                if ((r = close_nointr(fd)) < 0) {
                        /* Valgrind has its own FD and doesn't want to have it closed */
                        if (errno != EBADF)
                                goto finish;
                }
        }

        r = 0;

finish:
        closedir(d);
        return r;
}

bool chars_intersect(const char *a, const char *b) {
        const char *p;

        /* Returns true if any of the chars in a are in b. */
        for (p = a; *p; p++)
                if (strchr(b, *p))
                        return true;

        return false;
}

char *format_timestamp(char *buf, size_t l, usec_t t) {
        struct tm tm;
        time_t sec;

        assert(buf);
        assert(l > 0);

        if (t <= 0)
                return NULL;

        sec = (time_t) (t / USEC_PER_SEC);

        if (strftime(buf, l, "%a, %d %b %Y %H:%M:%S %z", localtime_r(&sec, &tm)) <= 0)
                return NULL;

        return buf;
}

char *format_timestamp_pretty(char *buf, size_t l, usec_t t) {
        usec_t n, d;

        n = now(CLOCK_REALTIME);

        if (t <= 0 || t > n || t + USEC_PER_DAY*7 <= t)
                return NULL;

        d = n - t;

        if (d >= USEC_PER_YEAR)
                snprintf(buf, l, "%llu years and %llu months ago",
                         (unsigned long long) (d / USEC_PER_YEAR),
                         (unsigned long long) ((d % USEC_PER_YEAR) / USEC_PER_MONTH));
        else if (d >= USEC_PER_MONTH)
                snprintf(buf, l, "%llu months and %llu days ago",
                         (unsigned long long) (d / USEC_PER_MONTH),
                         (unsigned long long) ((d % USEC_PER_MONTH) / USEC_PER_DAY));
        else if (d >= USEC_PER_WEEK)
                snprintf(buf, l, "%llu weeks and %llu days ago",
                         (unsigned long long) (d / USEC_PER_WEEK),
                         (unsigned long long) ((d % USEC_PER_WEEK) / USEC_PER_DAY));
        else if (d >= 2*USEC_PER_DAY)
                snprintf(buf, l, "%llu days ago", (unsigned long long) (d / USEC_PER_DAY));
        else if (d >= 25*USEC_PER_HOUR)
                snprintf(buf, l, "1 day and %lluh ago",
                         (unsigned long long) ((d - USEC_PER_DAY) / USEC_PER_HOUR));
        else if (d >= 6*USEC_PER_HOUR)
                snprintf(buf, l, "%lluh ago",
                         (unsigned long long) (d / USEC_PER_HOUR));
        else if (d >= USEC_PER_HOUR)
                snprintf(buf, l, "%lluh %llumin ago",
                         (unsigned long long) (d / USEC_PER_HOUR),
                         (unsigned long long) ((d % USEC_PER_HOUR) / USEC_PER_MINUTE));
        else if (d >= 5*USEC_PER_MINUTE)
                snprintf(buf, l, "%llumin ago",
                         (unsigned long long) (d / USEC_PER_MINUTE));
        else if (d >= USEC_PER_MINUTE)
                snprintf(buf, l, "%llumin %llus ago",
                         (unsigned long long) (d / USEC_PER_MINUTE),
                         (unsigned long long) ((d % USEC_PER_MINUTE) / USEC_PER_SEC));
        else if (d >= USEC_PER_SEC)
                snprintf(buf, l, "%llus ago",
                         (unsigned long long) (d / USEC_PER_SEC));
        else if (d >= USEC_PER_MSEC)
                snprintf(buf, l, "%llums ago",
                         (unsigned long long) (d / USEC_PER_MSEC));
        else if (d > 0)
                snprintf(buf, l, "%lluus ago",
                         (unsigned long long) d);
        else
                snprintf(buf, l, "now");

        buf[l-1] = 0;
        return buf;
}

char *format_timespan(char *buf, size_t l, usec_t t) {
        static const struct {
                const char *suffix;
                usec_t usec;
        } table[] = {
                { "w", USEC_PER_WEEK },
                { "d", USEC_PER_DAY },
                { "h", USEC_PER_HOUR },
                { "min", USEC_PER_MINUTE },
                { "s", USEC_PER_SEC },
                { "ms", USEC_PER_MSEC },
                { "us", 1 },
        };

        unsigned i;
        char *p = buf;

        assert(buf);
        assert(l > 0);

        if (t == (usec_t) -1)
                return NULL;

        if (t == 0) {
                snprintf(p, l, "0");
                p[l-1] = 0;
                return p;
        }

        /* The result of this function can be parsed with parse_usec */

        for (i = 0; i < ELEMENTSOF(table); i++) {
                int k;
                size_t n;

                if (t < table[i].usec)
                        continue;

                if (l <= 1)
                        break;

                k = snprintf(p, l, "%s%llu%s", p > buf ? " " : "", (unsigned long long) (t / table[i].usec), table[i].suffix);
                n = MIN((size_t) k, l);

                l -= n;
                p += n;

                t %= table[i].usec;
        }

        *p = 0;

        return buf;
}

bool fstype_is_network(const char *fstype) {
        static const char * const table[] = {
                "cifs",
                "smbfs",
                "ncpfs",
                "nfs",
                "nfs4",
                "gfs",
                "gfs2"
        };

        unsigned i;

        for (i = 0; i < ELEMENTSOF(table); i++)
                if (streq(table[i], fstype))
                        return true;

        return false;
}

int chvt(int vt) {
        int fd, r = 0;

        if ((fd = open("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC)) < 0)
                return -errno;

        if (vt < 0) {
                int tiocl[2] = {
                        TIOCL_GETKMSGREDIRECT,
                        0
                };

                if (ioctl(fd, TIOCLINUX, tiocl) < 0)
                        return -errno;

                vt = tiocl[0] <= 0 ? 1 : tiocl[0];
        }

        if (ioctl(fd, VT_ACTIVATE, vt) < 0)
                r = -errno;

        close_nointr_nofail(r);
        return r;
}

int read_one_char(FILE *f, char *ret, bool *need_nl) {
        struct termios old_termios, new_termios;
        char c;
        char line[1024];

        assert(f);
        assert(ret);

        if (tcgetattr(fileno(f), &old_termios) >= 0) {
                new_termios = old_termios;

                new_termios.c_lflag &= ~ICANON;
                new_termios.c_cc[VMIN] = 1;
                new_termios.c_cc[VTIME] = 0;

                if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
                        size_t k;

                        k = fread(&c, 1, 1, f);

                        tcsetattr(fileno(f), TCSADRAIN, &old_termios);

                        if (k <= 0)
                                return -EIO;

                        if (need_nl)
                                *need_nl = c != '\n';

                        *ret = c;
                        return 0;
                }
        }

        if (!(fgets(line, sizeof(line), f)))
                return -EIO;

        truncate_nl(line);

        if (strlen(line) != 1)
                return -EBADMSG;

        if (need_nl)
                *need_nl = false;

        *ret = line[0];
        return 0;
}

int ask(char *ret, const char *replies, const char *text, ...) {
        bool on_tty;

        assert(ret);
        assert(replies);
        assert(text);

        on_tty = isatty(STDOUT_FILENO);

        for (;;) {
                va_list ap;
                char c;
                int r;
                bool need_nl = true;

                if (on_tty)
                        fputs("\x1B[1m", stdout);

                va_start(ap, text);
                vprintf(text, ap);
                va_end(ap);

                if (on_tty)
                        fputs("\x1B[0m", stdout);

                fflush(stdout);

                if ((r = read_one_char(stdin, &c, &need_nl)) < 0) {

                        if (r == -EBADMSG) {
                                puts("Bad input, please try again.");
                                continue;
                        }

                        putchar('\n');
                        return r;
                }

                if (need_nl)
                        putchar('\n');

                if (strchr(replies, c)) {
                        *ret = c;
                        return 0;
                }

                puts("Read unexpected character, please try again.");
        }
}

int reset_terminal(int fd) {
        struct termios termios;
        int r = 0;
        long arg;

        /* Set terminal to some sane defaults */

        assert(fd >= 0);

        /* We leave locked terminal attributes untouched, so that
         * Plymouth may set whatever it wants to set, and we don't
         * interfere with that. */

        /* Disable exclusive mode, just in case */
        ioctl(fd, TIOCNXCL);

        /* Enable console unicode mode */
        arg = K_UNICODE;
        ioctl(fd, KDSKBMODE, &arg);

        if (tcgetattr(fd, &termios) < 0) {
                r = -errno;
                goto finish;
        }

        /* We only reset the stuff that matters to the software. How
         * hardware is set up we don't touch assuming that somebody
         * else will do that for us */

        termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
        termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
        termios.c_oflag |= ONLCR;
        termios.c_cflag |= CREAD;
        termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;

        termios.c_cc[VINTR]    =   03;  /* ^C */
        termios.c_cc[VQUIT]    =  034;  /* ^\ */
        termios.c_cc[VERASE]   = 0177;
        termios.c_cc[VKILL]    =  025;  /* ^X */
        termios.c_cc[VEOF]     =   04;  /* ^D */
        termios.c_cc[VSTART]   =  021;  /* ^Q */
        termios.c_cc[VSTOP]    =  023;  /* ^S */
        termios.c_cc[VSUSP]    =  032;  /* ^Z */
        termios.c_cc[VLNEXT]   =  026;  /* ^V */
        termios.c_cc[VWERASE]  =  027;  /* ^W */
        termios.c_cc[VREPRINT] =  022;  /* ^R */
        termios.c_cc[VEOL]     =    0;
        termios.c_cc[VEOL2]    =    0;

        termios.c_cc[VTIME]  = 0;
        termios.c_cc[VMIN]   = 1;

        if (tcsetattr(fd, TCSANOW, &termios) < 0)
                r = -errno;

finish:
        /* Just in case, flush all crap out */
        tcflush(fd, TCIOFLUSH);

        return r;
}

int open_terminal(const char *name, int mode) {
        int fd, r;
        unsigned c = 0;

        /*
         * If a TTY is in the process of being closed opening it might
         * cause EIO. This is horribly awful, but unlikely to be
         * changed in the kernel. Hence we work around this problem by
         * retrying a couple of times.
         *
         * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
         */

        for (;;) {
                if ((fd = open(name, mode)) >= 0)
                        break;

                if (errno != EIO)
                        return -errno;

                if (c >= 20)
                        return -errno;

                usleep(50 * USEC_PER_MSEC);
                c++;
        }

        if (fd < 0)
                return -errno;

        if ((r = isatty(fd)) < 0) {
                close_nointr_nofail(fd);
                return -errno;
        }

        if (!r) {
                close_nointr_nofail(fd);
                return -ENOTTY;
        }

        return fd;
}

int flush_fd(int fd) {
        struct pollfd pollfd;

        zero(pollfd);
        pollfd.fd = fd;
        pollfd.events = POLLIN;

        for (;;) {
                char buf[1024];
                ssize_t l;
                int r;

                if ((r = poll(&pollfd, 1, 0)) < 0) {

                        if (errno == EINTR)
                                continue;

                        return -errno;
                }

                if (r == 0)
                        return 0;

                if ((l = read(fd, buf, sizeof(buf))) < 0) {

                        if (errno == EINTR)
                                continue;

                        if (errno == EAGAIN)
                                return 0;

                        return -errno;
                }

                if (l <= 0)
                        return 0;
        }
}

int acquire_terminal(const char *name, bool fail, bool force, bool ignore_tiocstty_eperm) {
        int fd = -1, notify = -1, r, wd = -1;

        assert(name);

        /* We use inotify to be notified when the tty is closed. We
         * create the watch before checking if we can actually acquire
         * it, so that we don't lose any event.
         *
         * Note: strictly speaking this actually watches for the
         * device being closed, it does *not* really watch whether a
         * tty loses its controlling process. However, unless some
         * rogue process uses TIOCNOTTY on /dev/tty *after* closing
         * its tty otherwise this will not become a problem. As long
         * as the administrator makes sure not configure any service
         * on the same tty as an untrusted user this should not be a
         * problem. (Which he probably should not do anyway.) */

        if (!fail && !force) {
                if ((notify = inotify_init1(IN_CLOEXEC)) < 0) {
                        r = -errno;
                        goto fail;
                }

                if ((wd = inotify_add_watch(notify, name, IN_CLOSE)) < 0) {
                        r = -errno;
                        goto fail;
                }
        }

        for (;;) {
                if (notify >= 0)
                        if ((r = flush_fd(notify)) < 0)
                                goto fail;

                /* We pass here O_NOCTTY only so that we can check the return
                 * value TIOCSCTTY and have a reliable way to figure out if we
                 * successfully became the controlling process of the tty */
                if ((fd = open_terminal(name, O_RDWR|O_NOCTTY)) < 0)
                        return -errno;

                /* First, try to get the tty */
                r = ioctl(fd, TIOCSCTTY, force);

                /* Sometimes it makes sense to ignore TIOCSCTTY
                 * returning EPERM, i.e. when very likely we already
                 * are have this controlling terminal. */
                if (r < 0 && errno == EPERM && ignore_tiocstty_eperm)
                        r = 0;

                if (r < 0 && (force || fail || errno != EPERM)) {
                        r = -errno;
                        goto fail;
                }

                if (r >= 0)
                        break;

                assert(!fail);
                assert(!force);
                assert(notify >= 0);

                for (;;) {
                        uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
                        ssize_t l;
                        struct inotify_event *e;

                        if ((l = read(notify, &inotify_buffer, sizeof(inotify_buffer))) < 0) {

                                if (errno == EINTR)
                                        continue;

                                r = -errno;
                                goto fail;
                        }

                        e = (struct inotify_event*) inotify_buffer;

                        while (l > 0) {
                                size_t step;

                                if (e->wd != wd || !(e->mask & IN_CLOSE)) {
                                        r = -EIO;
                                        goto fail;
                                }

                                step = sizeof(struct inotify_event) + e->len;
                                assert(step <= (size_t) l);

                                e = (struct inotify_event*) ((uint8_t*) e + step);
                                l -= step;
                        }

                        break;
                }

                /* We close the tty fd here since if the old session
                 * ended our handle will be dead. It's important that
                 * we do this after sleeping, so that we don't enter
                 * an endless loop. */
                close_nointr_nofail(fd);
        }

        if (notify >= 0)
                close_nointr_nofail(notify);

        if ((r = reset_terminal(fd)) < 0)
                log_warning("Failed to reset terminal: %s", strerror(-r));

        return fd;

fail:
        if (fd >= 0)
                close_nointr_nofail(fd);

        if (notify >= 0)
                close_nointr_nofail(notify);

        return r;
}

int release_terminal(void) {
        int r = 0, fd;
        struct sigaction sa_old, sa_new;

        if ((fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY)) < 0)
                return -errno;

        /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
         * by our own TIOCNOTTY */

        zero(sa_new);
        sa_new.sa_handler = SIG_IGN;
        sa_new.sa_flags = SA_RESTART;
        assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);

        if (ioctl(fd, TIOCNOTTY) < 0)
                r = -errno;

        assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);

        close_nointr_nofail(fd);
        return r;
}

int sigaction_many(const struct sigaction *sa, ...) {
        va_list ap;
        int r = 0, sig;

        va_start(ap, sa);
        while ((sig = va_arg(ap, int)) > 0)
                if (sigaction(sig, sa, NULL) < 0)
                        r = -errno;
        va_end(ap);

        return r;
}

int ignore_signals(int sig, ...) {
        struct sigaction sa;
        va_list ap;
        int r = 0;

        zero(sa);
        sa.sa_handler = SIG_IGN;
        sa.sa_flags = SA_RESTART;

        if (sigaction(sig, &sa, NULL) < 0)
                r = -errno;

        va_start(ap, sig);
        while ((sig = va_arg(ap, int)) > 0)
                if (sigaction(sig, &sa, NULL) < 0)
                        r = -errno;
        va_end(ap);

        return r;
}

int default_signals(int sig, ...) {
        struct sigaction sa;
        va_list ap;
        int r = 0;

        zero(sa);
        sa.sa_handler = SIG_DFL;
        sa.sa_flags = SA_RESTART;

        if (sigaction(sig, &sa, NULL) < 0)
                r = -errno;

        va_start(ap, sig);
        while ((sig = va_arg(ap, int)) > 0)
                if (sigaction(sig, &sa, NULL) < 0)
                        r = -errno;
        va_end(ap);

        return r;
}

int close_pipe(int p[]) {
        int a = 0, b = 0;

        assert(p);

        if (p[0] >= 0) {
                a = close_nointr(p[0]);
                p[0] = -1;
        }

        if (p[1] >= 0) {
                b = close_nointr(p[1]);
                p[1] = -1;
        }

        return a < 0 ? a : b;
}

ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
        uint8_t *p;
        ssize_t n = 0;

        assert(fd >= 0);
        assert(buf);

        p = buf;

        while (nbytes > 0) {
                ssize_t k;

                if ((k = read(fd, p, nbytes)) <= 0) {

                        if (k < 0 && errno == EINTR)
                                continue;

                        if (k < 0 && errno == EAGAIN && do_poll) {
                                struct pollfd pollfd;

                                zero(pollfd);
                                pollfd.fd = fd;
                                pollfd.events = POLLIN;

                                if (poll(&pollfd, 1, -1) < 0) {
                                        if (errno == EINTR)
                                                continue;

                                        return n > 0 ? n : -errno;
                                }

                                if (pollfd.revents != POLLIN)
                                        return n > 0 ? n : -EIO;

                                continue;
                        }

                        return n > 0 ? n : (k < 0 ? -errno : 0);
                }

                p += k;
                nbytes -= k;
                n += k;
        }

        return n;
}

ssize_t loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
        const uint8_t *p;
        ssize_t n = 0;

        assert(fd >= 0);
        assert(buf);

        p = buf;

        while (nbytes > 0) {
                ssize_t k;

                if ((k = write(fd, p, nbytes)) <= 0) {

                        if (k < 0 && errno == EINTR)
                                continue;

                        if (k < 0 && errno == EAGAIN && do_poll) {
                                struct pollfd pollfd;

                                zero(pollfd);
                                pollfd.fd = fd;
                                pollfd.events = POLLOUT;

                                if (poll(&pollfd, 1, -1) < 0) {
                                        if (errno == EINTR)
                                                continue;

                                        return n > 0 ? n : -errno;
                                }

                                if (pollfd.revents != POLLOUT)
                                        return n > 0 ? n : -EIO;

                                continue;
                        }

                        return n > 0 ? n : (k < 0 ? -errno : 0);
                }

                p += k;
                nbytes -= k;
                n += k;
        }

        return n;
}

int path_is_mount_point(const char *t) {
        struct stat a, b;
        char *parent;
        int r;

        if (lstat(t, &a) < 0) {
                if (errno == ENOENT)
                        return 0;

                return -errno;
        }

        if ((r = parent_of_path(t, &parent)) < 0)
                return r;

        r = lstat(parent, &b);
        free(parent);

        if (r < 0)
                return -errno;

        return a.st_dev != b.st_dev;
}

int parse_usec(const char *t, usec_t *usec) {
        static const struct {
                const char *suffix;
                usec_t usec;
        } table[] = {
                { "sec", USEC_PER_SEC },
                { "s", USEC_PER_SEC },
                { "min", USEC_PER_MINUTE },
                { "hr", USEC_PER_HOUR },
                { "h", USEC_PER_HOUR },
                { "d", USEC_PER_DAY },
                { "w", USEC_PER_WEEK },
                { "msec", USEC_PER_MSEC },
                { "ms", USEC_PER_MSEC },
                { "m", USEC_PER_MINUTE },
                { "usec", 1ULL },
                { "us", 1ULL },
                { "", USEC_PER_SEC },
        };

        const char *p;
        usec_t r = 0;

        assert(t);
        assert(usec);

        p = t;
        do {
                long long l;
                char *e;
                unsigned i;

                errno = 0;
                l = strtoll(p, &e, 10);

                if (errno != 0)
                        return -errno;

                if (l < 0)
                        return -ERANGE;

                if (e == p)
                        return -EINVAL;

                e += strspn(e, WHITESPACE);

                for (i = 0; i < ELEMENTSOF(table); i++)
                        if (startswith(e, table[i].suffix)) {
                                r += (usec_t) l * table[i].usec;
                                p = e + strlen(table[i].suffix);
                                break;
                        }

                if (i >= ELEMENTSOF(table))
                        return -EINVAL;

        } while (*p != 0);

        *usec = r;

        return 0;
}

int make_stdio(int fd) {
        int r, s, t;

        assert(fd >= 0);

        r = dup2(fd, STDIN_FILENO);
        s = dup2(fd, STDOUT_FILENO);
        t = dup2(fd, STDERR_FILENO);

        if (fd >= 3)
                close_nointr_nofail(fd);

        if (r < 0 || s < 0 || t < 0)
                return -errno;

        return 0;
}

int make_null_stdio(void) {
        int null_fd;

        if ((null_fd = open("/dev/null", O_RDWR|O_NOCTTY)) < 0)
                return -errno;

        return make_stdio(null_fd);
}

bool is_device_path(const char *path) {

        /* Returns true on paths that refer to a device, either in
         * sysfs or in /dev */

        return
                path_startswith(path, "/dev/") ||
                path_startswith(path, "/sys/");
}

int dir_is_empty(const char *path) {
        DIR *d;
        int r;
        struct dirent buf, *de;

        if (!(d = opendir(path)))
                return -errno;

        for (;;) {
                if ((r = readdir_r(d, &buf, &de)) > 0) {
                        r = -r;
                        break;
                }

                if (!de) {
                        r = 1;
                        break;
                }

                if (!ignore_file(de->d_name)) {
                        r = 0;
                        break;
                }
        }

        closedir(d);
        return r;
}

unsigned long long random_ull(void) {
        int fd;
        uint64_t ull;
        ssize_t r;

        if ((fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0)
                goto fallback;

        r = loop_read(fd, &ull, sizeof(ull), true);
        close_nointr_nofail(fd);

        if (r != sizeof(ull))
                goto fallback;

        return ull;

fallback:
        return random() * RAND_MAX + random();
}

void rename_process(const char name[8]) {
        assert(name);

        prctl(PR_SET_NAME, name);

        /* This is a like a poor man's setproctitle(). The string
         * passed should fit in 7 chars (i.e. the length of
         * "systemd") */

        if (program_invocation_name)
                strncpy(program_invocation_name, name, strlen(program_invocation_name));
}

void sigset_add_many(sigset_t *ss, ...) {
        va_list ap;
        int sig;

        assert(ss);

        va_start(ap, ss);
        while ((sig = va_arg(ap, int)) > 0)
                assert_se(sigaddset(ss, sig) == 0);
        va_end(ap);
}

char* gethostname_malloc(void) {
        struct utsname u;

        assert_se(uname(&u) >= 0);

        if (u.nodename[0])
                return strdup(u.nodename);

        return strdup(u.sysname);
}

char* getlogname_malloc(void) {
        uid_t uid;
        long bufsize;
        char *buf, *name;
        struct passwd pwbuf, *pw = NULL;
        struct stat st;

        if (isatty(STDIN_FILENO) && fstat(STDIN_FILENO, &st) >= 0)
                uid = st.st_uid;
        else
                uid = getuid();

        /* Shortcut things to avoid NSS lookups */
        if (uid == 0)
                return strdup("root");

        if ((bufsize = sysconf(_SC_GETPW_R_SIZE_MAX)) <= 0)
                bufsize = 4096;

        if (!(buf = malloc(bufsize)))
                return NULL;

        if (getpwuid_r(uid, &pwbuf, buf, bufsize, &pw) == 0 && pw) {
                name = strdup(pw->pw_name);
                free(buf);
                return name;
        }

        free(buf);

        if (asprintf(&name, "%lu", (unsigned long) uid) < 0)
                return NULL;

        return name;
}

int getttyname_malloc(int fd, char **r) {
        char path[PATH_MAX], *c;
        int k;

        assert(r);

        if ((k = ttyname_r(fd, path, sizeof(path))) != 0)
                return -k;

        char_array_0(path);

        if (!(c = strdup(startswith(path, "/dev/") ? path + 5 : path)))
                return -ENOMEM;

        *r = c;
        return 0;
}

int getttyname_harder(int fd, char **r) {
        int k;
        char *s;

        if ((k = getttyname_malloc(fd, &s)) < 0)
                return k;

        if (streq(s, "tty")) {
                free(s);
                return get_ctty(r);
        }

        *r = s;
        return 0;
}

int get_ctty_devnr(dev_t *d) {
        int k;
        char line[256], *p;
        unsigned long ttynr;
        FILE *f;

        if (!(f = fopen("/proc/self/stat", "r")))
                return -errno;

        if (!(fgets(line, sizeof(line), f))) {
                k = -errno;
                fclose(f);
                return k;
        }

        fclose(f);

        if (!(p = strrchr(line, ')')))
                return -EIO;

        p++;

        if (sscanf(p, " "
                   "%*c "  /* state */
                   "%*d "  /* ppid */
                   "%*d "  /* pgrp */
                   "%*d "  /* session */
                   "%lu ", /* ttynr */
                   &ttynr) != 1)
                return -EIO;

        *d = (dev_t) ttynr;
        return 0;
}

int get_ctty(char **r) {
        int k;
        char fn[128], *s, *b, *p;
        dev_t devnr;

        assert(r);

        if ((k = get_ctty_devnr(&devnr)) < 0)
                return k;

        snprintf(fn, sizeof(fn), "/dev/char/%u:%u", major(devnr), minor(devnr));
        char_array_0(fn);

        if ((k = readlink_malloc(fn, &s)) < 0) {

                if (k != -ENOENT)
                        return k;

                /* Probably something like the ptys which have no
                 * symlink in /dev/char. Let's return something
                 * vaguely useful. */

                if (!(b = strdup(fn + 5)))
                        return -ENOMEM;

                *r = b;
                return 0;
        }

        if (startswith(s, "/dev/"))
                p = s + 5;
        else if (startswith(s, "../"))
                p = s + 3;
        else
                p = s;

        b = strdup(p);
        free(s);

        if (!b)
                return -ENOMEM;

        *r = b;
        return 0;
}

static int rm_rf_children(int fd, bool only_dirs) {
        DIR *d;
        int ret = 0;

        assert(fd >= 0);

        /* This returns the first error we run into, but nevertheless
         * tries to go on */

        if (!(d = fdopendir(fd))) {
                close_nointr_nofail(fd);

                return errno == ENOENT ? 0 : -errno;
        }

        for (;;) {
                struct dirent buf, *de;
                bool is_dir;
                int r;

                if ((r = readdir_r(d, &buf, &de)) != 0) {
                        if (ret == 0)
                                ret = -r;
                        break;
                }

                if (!de)
                        break;

                if (streq(de->d_name, ".") || streq(de->d_name, ".."))
                        continue;

                if (de->d_type == DT_UNKNOWN) {
                        struct stat st;

                        if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        is_dir = S_ISDIR(st.st_mode);
                } else
                        is_dir = de->d_type == DT_DIR;

                if (is_dir) {
                        int subdir_fd;

                        if ((subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC)) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        if ((r = rm_rf_children(subdir_fd, only_dirs)) < 0) {
                                if (ret == 0)
                                        ret = r;
                        }

                        if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }
                } else  if (!only_dirs) {

                        if (unlinkat(fd, de->d_name, 0) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }
                }
        }

        closedir(d);

        return ret;
}

int rm_rf(const char *path, bool only_dirs, bool delete_root) {
        int fd;
        int r;

        assert(path);

        if ((fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC)) < 0) {

                if (errno != ENOTDIR)
                        return -errno;

                if (delete_root && !only_dirs)
                        if (unlink(path) < 0)
                                return -errno;

                return 0;
        }

        r = rm_rf_children(fd, only_dirs);

        if (delete_root)
                if (rmdir(path) < 0) {
                        if (r == 0)
                                r = -errno;
                }

        return r;
}

int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
        assert(path);

        /* Under the assumption that we are running privileged we
         * first change the access mode and only then hand out
         * ownership to avoid a window where access is too open. */

        if (chmod(path, mode) < 0)
                return -errno;

        if (chown(path, uid, gid) < 0)
                return -errno;

        return 0;
}

cpu_set_t* cpu_set_malloc(unsigned *ncpus) {
        cpu_set_t *r;
        unsigned n = 1024;

        /* Allocates the cpuset in the right size */

        for (;;) {
                if (!(r = CPU_ALLOC(n)))
                        return NULL;

                if (sched_getaffinity(0, CPU_ALLOC_SIZE(n), r) >= 0) {
                        CPU_ZERO_S(CPU_ALLOC_SIZE(n), r);

                        if (ncpus)
                                *ncpus = n;

                        return r;
                }

                CPU_FREE(r);

                if (errno != EINVAL)
                        return NULL;

                n *= 2;
        }
}

void status_vprintf(const char *format, va_list ap) {
        char *s = NULL;
        int fd = -1;

        assert(format);

        /* This independent of logging, as status messages are
         * optional and go exclusively to the console. */

        if (vasprintf(&s, format, ap) < 0)
                goto finish;

        if ((fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0)
                goto finish;

        write(fd, s, strlen(s));

finish:
        free(s);

        if (fd >= 0)
                close_nointr_nofail(fd);
}

void status_printf(const char *format, ...) {
        va_list ap;

        assert(format);

        va_start(ap, format);
        status_vprintf(format, ap);
        va_end(ap);
}

void status_welcome(void) {
        char *pretty_name = NULL, *ansi_color = NULL;
        const char *const_pretty = NULL, *const_color = NULL;
        int r;

        if ((r = parse_env_file("/etc/os-release", NEWLINE,
                                "PRETTY_NAME", &pretty_name,
                                "ANSI_COLOR", &ansi_color,
                                NULL)) < 0) {

                if (r != -ENOENT)
                        log_warning("Failed to read /etc/os-release: %s", strerror(-r));
        }

#if defined(TARGET_FEDORA)
        if (!pretty_name) {
                if ((r = read_one_line_file("/etc/system-release", &pretty_name)) < 0) {

                        if (r != -ENOENT)
                                log_warning("Failed to read /etc/system-release: %s", strerror(-r));
                } else
                        truncate_nl(pretty_name);
        }

        if (!ansi_color && pretty_name) {

                /* This tries to mimic the color magic the old Red Hat sysinit
                 * script did. */

                if (startswith(pretty_name, "Red Hat"))
                        const_color = "0;31"; /* Red for RHEL */
                else if (startswith(pretty_name, "Fedora"))
                        const_color = "0;34"; /* Blue for Fedora */
        }

#elif defined(TARGET_SUSE)

        if (!pretty_name) {
                if ((r = read_one_line_file("/etc/SuSE-release", &pretty_name)) < 0) {

                        if (r != -ENOENT)
                                log_warning("Failed to read /etc/SuSE-release: %s", strerror(-r));
                } else
                        truncate_nl(pretty_name);
        }

        if (!ansi_color)
                const_color = "0;32"; /* Green for openSUSE */

#elif defined(TARGET_GENTOO)

        if (!pretty_name) {
                if ((r = read_one_line_file("/etc/gentoo-release", &pretty_name)) < 0) {

                        if (r != -ENOENT)
                                log_warning("Failed to read /etc/gentoo-release: %s", strerror(-r));
                } else
                        truncate_nl(pretty_name);
        }

        if (!ansi_color)
                const_color = "1;34"; /* Light Blue for Gentoo */

#elif defined(TARGET_ALTLINUX)

        if (!pretty_name) {
                if ((r = read_one_line_file("/etc/altlinux-release", &pretty_name)) < 0) {

                        if (r != -ENOENT)
                                log_warning("Failed to read /etc/altlinux-release: %s", strerror(-r));
                } else
                        truncate_nl(pretty_name);
        }

        if (!ansi_color)
                const_color = "0;36"; /* Cyan for ALTLinux */


#elif defined(TARGET_DEBIAN)

        if (!pretty_name) {
                char *version;

                if ((r = read_one_line_file("/etc/debian_version", &version)) < 0) {

                        if (r != -ENOENT)
                                log_warning("Failed to read /etc/debian_version: %s", strerror(-r));
                } else {
                        truncate_nl(version);
                        pretty_name = strappend("Debian ", version);
                        free(version);

                        if (!pretty_name)
                                log_warning("Failed to allocate Debian version string.");
                }
        }

        if (!ansi_color)
                const_color = "1;31"; /* Light Red for Debian */

#elif defined(TARGET_UBUNTU)

        if ((r = parse_env_file("/etc/lsb-release", NEWLINE,
                                "DISTRIB_DESCRIPTION", &pretty_name,
                                NULL)) < 0) {

                if (r != -ENOENT)
                        log_warning("Failed to read /etc/lsb-release: %s", strerror(-r));
        }

        if (!ansi_color)
                const_color = "0;33"; /* Orange/Brown for Ubuntu */

#endif

        if (!pretty_name && !const_pretty)
                const_pretty = "Linux";

        if (!ansi_color && !const_color)
                const_color = "1";

        status_printf("\nWelcome to \x1B[%sm%s\x1B[0m!\n\n",
                      const_color ? const_color : ansi_color,
                      const_pretty ? const_pretty : pretty_name);

        free(ansi_color);
        free(pretty_name);
}

char *replace_env(const char *format, char **env) {
        enum {
                WORD,
                CURLY,
                VARIABLE
        } state = WORD;

        const char *e, *word = format;
        char *r = NULL, *k;

        assert(format);

        for (e = format; *e; e ++) {

                switch (state) {

                case WORD:
                        if (*e == '$')
                                state = CURLY;
                        break;

                case CURLY:
                        if (*e == '{') {
                                if (!(k = strnappend(r, word, e-word-1)))
                                        goto fail;

                                free(r);
                                r = k;

                                word = e-1;
                                state = VARIABLE;

                        } else if (*e == '$') {
                                if (!(k = strnappend(r, word, e-word)))
                                        goto fail;

                                free(r);
                                r = k;

                                word = e+1;
                                state = WORD;
                        } else
                                state = WORD;
                        break;

                case VARIABLE:
                        if (*e == '}') {
                                const char *t;

                                if (!(t = strv_env_get_with_length(env, word+2, e-word-2)))
                                        t = "";

                                if (!(k = strappend(r, t)))
                                        goto fail;

                                free(r);
                                r = k;

                                word = e+1;
                                state = WORD;
                        }
                        break;
                }
        }

        if (!(k = strnappend(r, word, e-word)))
                goto fail;

        free(r);
        return k;

fail:
        free(r);
        return NULL;
}

char **replace_env_argv(char **argv, char **env) {
        char **r, **i;
        unsigned k = 0, l = 0;

        l = strv_length(argv);

        if (!(r = new(char*, l+1)))
                return NULL;

        STRV_FOREACH(i, argv) {

                /* If $FOO appears as single word, replace it by the split up variable */
                if ((*i)[0] == '$' && (*i)[1] != '{') {
                        char *e;
                        char **w, **m;
                        unsigned q;

                        if ((e = strv_env_get(env, *i+1))) {

                                if (!(m = strv_split_quoted(e))) {
                                        r[k] = NULL;
                                        strv_free(r);
                                        return NULL;
                                }
                        } else
                                m = NULL;

                        q = strv_length(m);
                        l = l + q - 1;

                        if (!(w = realloc(r, sizeof(char*) * (l+1)))) {
                                r[k] = NULL;
                                strv_free(r);
                                strv_free(m);
                                return NULL;
                        }

                        r = w;
                        if (m) {
                                memcpy(r + k, m, q * sizeof(char*));
                                free(m);
                        }

                        k += q;
                        continue;
                }

                /* If ${FOO} appears as part of a word, replace it by the variable as-is */
                if (!(r[k++] = replace_env(*i, env))) {
                        strv_free(r);
                        return NULL;
                }
        }

        r[k] = NULL;
        return r;
}

int columns(void) {
        static __thread int parsed_columns = 0;
        const char *e;

        if (parsed_columns > 0)
                return parsed_columns;

        if ((e = getenv("COLUMNS")))
                parsed_columns = atoi(e);

        if (parsed_columns <= 0) {
                struct winsize ws;
                zero(ws);

                if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
                        parsed_columns = ws.ws_col;
        }

        if (parsed_columns <= 0)
                parsed_columns = 80;

        return parsed_columns;
}

int running_in_chroot(void) {
        struct stat a, b;

        zero(a);
        zero(b);

        /* Only works as root */

        if (stat("/proc/1/root", &a) < 0)
                return -errno;

        if (stat("/", &b) < 0)
                return -errno;

        return
                a.st_dev != b.st_dev ||
                a.st_ino != b.st_ino;
}

char *ellipsize(const char *s, unsigned length, unsigned percent) {
        size_t l, x;
        char *r;

        assert(s);
        assert(percent <= 100);
        assert(length >= 3);

        l = strlen(s);

        if (l <= 3 || l <= length)
                return strdup(s);

        if (!(r = new0(char, length+1)))
                return r;

        x = (length * percent) / 100;

        if (x > length - 3)
                x = length - 3;

        memcpy(r, s, x);
        r[x] = '.';
        r[x+1] = '.';
        r[x+2] = '.';
        memcpy(r + x + 3,
               s + l - (length - x - 3),
               length - x - 3);

        return r;
}

int touch(const char *path) {
        int fd;

        assert(path);

        if ((fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, 0666)) < 0)
                return -errno;

        close_nointr_nofail(fd);
        return 0;
}

char *unquote(const char *s, const char* quotes) {
        size_t l;
        assert(s);

        if ((l = strlen(s)) < 2)
                return strdup(s);

        if (strchr(quotes, s[0]) && s[l-1] == s[0])
                return strndup(s+1, l-2);

        return strdup(s);
}

char *normalize_env_assignment(const char *s) {
        char *name, *value, *p, *r;

        p = strchr(s, '=');

        if (!p) {
                if (!(r = strdup(s)))
                        return NULL;

                return strstrip(r);
        }

        if (!(name = strndup(s, p - s)))
                return NULL;

        if (!(p = strdup(p+1))) {
                free(name);
                return NULL;
        }

        value = unquote(strstrip(p), QUOTES);
        free(p);

        if (!value) {
                free(p);
                free(name);
                return NULL;
        }

        if (asprintf(&r, "%s=%s", name, value) < 0)
                r = NULL;

        free(value);
        free(name);

        return r;
}

int wait_for_terminate(pid_t pid, siginfo_t *status) {
        assert(pid >= 1);
        assert(status);

        for (;;) {
                zero(*status);

                if (waitid(P_PID, pid, status, WEXITED) < 0) {

                        if (errno == EINTR)
                                continue;

                        return -errno;
                }

                return 0;
        }
}

int wait_for_terminate_and_warn(const char *name, pid_t pid) {
        int r;
        siginfo_t status;

        assert(name);
        assert(pid > 1);

        if ((r = wait_for_terminate(pid, &status)) < 0) {
                log_warning("Failed to wait for %s: %s", name, strerror(-r));
                return r;
        }

        if (status.si_code == CLD_EXITED) {
                if (status.si_status != 0) {
                        log_warning("%s failed with error code %i.", name, status.si_status);
                        return -EPROTO;
                }

                log_debug("%s succeeded.", name);
                return 0;

        } else if (status.si_code == CLD_KILLED ||
                   status.si_code == CLD_DUMPED) {

                log_warning("%s terminated by signal %s.", name, signal_to_string(status.si_status));
                return -EPROTO;
        }

        log_warning("%s failed due to unknown reason.", name);
        return -EPROTO;

}

void freeze(void) {
        sync();

        for (;;)
                pause();
}

bool null_or_empty(struct stat *st) {
        assert(st);

        if (S_ISREG(st->st_mode) && st->st_size <= 0)
                return true;

        if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode))
                return true;

        return false;
}

DIR *xopendirat(int fd, const char *name, int flags) {
        int nfd;
        DIR *d;

        if ((nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags)) < 0)
                return NULL;

        if (!(d = fdopendir(nfd))) {
                close_nointr_nofail(nfd);
                return NULL;
        }

        return d;
}

int signal_from_string_try_harder(const char *s) {
        int signo;
        assert(s);

        if ((signo = signal_from_string(s)) <= 0)
                if (startswith(s, "SIG"))
                        return signal_from_string(s+3);

        return signo;
}

void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t) {

        assert(f);
        assert(name);
        assert(t);

        if (!dual_timestamp_is_set(t))
                return;

        fprintf(f, "%s=%llu %llu\n",
                name,
                (unsigned long long) t->realtime,
                (unsigned long long) t->monotonic);
}

void dual_timestamp_deserialize(const char *value, dual_timestamp *t) {
        unsigned long long a, b;

        assert(value);
        assert(t);

        if (sscanf(value, "%lli %llu", &a, &b) != 2)
                log_debug("Failed to parse finish timestamp value %s", value);
        else {
                t->realtime = a;
                t->monotonic = b;
        }
}

char *fstab_node_to_udev_node(const char *p) {
        char *dn, *t, *u;
        int r;

        /* FIXME: to follow udev's logic 100% we need to leave valid
         * UTF8 chars unescaped */

        if (startswith(p, "LABEL=")) {

                if (!(u = unquote(p+6, "\"\'")))
                        return NULL;

                t = xescape(u, "/ ");
                free(u);

                if (!t)
                        return NULL;

                r = asprintf(&dn, "/dev/disk/by-label/%s", t);
                free(t);

                if (r < 0)
                        return NULL;

                return dn;
        }

        if (startswith(p, "UUID=")) {

                if (!(u = unquote(p+5, "\"\'")))
                        return NULL;

                t = xescape(u, "/ ");
                free(u);

                if (!t)
                        return NULL;

                r = asprintf(&dn, "/dev/disk/by-uuid/%s", t);
                free(t);

                if (r < 0)
                        return NULL;

                return dn;
        }

        return strdup(p);
}

void filter_environ(const char *prefix) {
        int i, j;
        assert(prefix);

        if (!environ)
                return;

        for (i = 0, j = 0; environ[i]; i++) {

                if (startswith(environ[i], prefix))
                        continue;

                environ[j++] = environ[i];
        }

        environ[j] = NULL;
}

bool tty_is_vc(const char *tty) {
        assert(tty);

        if (startswith(tty, "/dev/"))
                tty += 5;

        return startswith(tty, "tty") &&
                tty[3] >= '0' && tty[3] <= '9';
}

const char *default_term_for_tty(const char *tty) {
        char *active = NULL;
        const char *term;

        assert(tty);

        if (startswith(tty, "/dev/"))
                tty += 5;

        /* Resolve where /dev/console is pointing when determining
         * TERM */
        if (streq(tty, "console"))
                if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
                        truncate_nl(active);

                        /* If multiple log outputs are configured the
                         * last one is what /dev/console points to */
                        if ((tty = strrchr(active, ' ')))
                                tty++;
                        else
                                tty = active;
                }

        term = tty_is_vc(tty) ? "TERM=linux" : "TERM=vt100";
        free(active);

        return term;
}

/* Returns a short identifier for the various VM implementations */
int detect_vm(const char **id) {

#if defined(__i386__) || defined(__x86_64__)

        /* Both CPUID and DMI are x86 specific interfaces... */

        static const char *const dmi_vendors[] = {
                "/sys/class/dmi/id/sys_vendor",
                "/sys/class/dmi/id/board_vendor",
                "/sys/class/dmi/id/bios_vendor"
        };

        static const char dmi_vendor_table[] =
                "QEMU\0"                  "qemu\0"
                /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
                "VMware\0"                "vmware\0"
                "VMW\0"                   "vmware\0"
                "Microsoft Corporation\0" "microsoft\0"
                "innotek GmbH\0"          "oracle\0"
                "Xen\0"                   "xen\0"
                "Bochs\0"                 "bochs\0"
                "\0";

        static const char cpuid_vendor_table[] =
                "XenVMMXenVMM\0"          "xen\0"
                "KVMKVMKVM\0"             "kvm\0"
                /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
                "VMwareVMware\0"          "vmware\0"
                /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
                "Microsoft Hv\0"          "microsoft\0"
                "\0";

        uint32_t eax, ecx;
        union {
                uint32_t sig32[3];
                char text[13];
        } sig;
        unsigned i;
        const char *j, *k;
        bool hypervisor;

        /* http://lwn.net/Articles/301888/ */
        zero(sig);

#if defined (__i386__)
#define REG_a "eax"
#define REG_b "ebx"
#elif defined (__amd64__)
#define REG_a "rax"
#define REG_b "rbx"
#endif

        /* First detect whether there is a hypervisor */
        eax = 1;
        __asm__ __volatile__ (
                /* ebx/rbx is being used for PIC! */
                "  push %%"REG_b"         \n\t"
                "  cpuid                  \n\t"
                "  pop %%"REG_b"          \n\t"

                : "=a" (eax), "=c" (ecx)
                : "0" (eax)
        );

        hypervisor = !!(ecx & ecx & 0x80000000U);

        if (hypervisor) {

                /* There is a hypervisor, see what it is */
                eax = 0x40000000U;
                __asm__ __volatile__ (
                        /* ebx/rbx is being used for PIC! */
                        "  push %%"REG_b"         \n\t"
                        "  cpuid                  \n\t"
                        "  mov %%ebx, %1          \n\t"
                        "  pop %%"REG_b"          \n\t"

                        : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
                        : "0" (eax)
                );

                NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
                        if (streq(sig.text, j)) {

                                if (id)
                                        *id = k;

                                return 1;
                        }
        }

        for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
                char *s;
                int r;
                const char *found = NULL;

                if ((r = read_one_line_file(dmi_vendors[i], &s)) < 0) {
                        if (r != -ENOENT)
                                return r;

                        continue;
                }

                NULSTR_FOREACH_PAIR(j, k, dmi_vendor_table)
                        if (startswith(s, j))
                                found = k;
                free(s);

                if (found) {
                        if (id)
                                *id = found;

                        return 1;
                }
        }

        if (hypervisor) {
                if (id)
                        *id = "other";

                return 1;
        }

#endif
        return 0;
}

/* Returns a short identifier for the various VM/container implementations */
int detect_virtualization(const char **id) {
        int r;

        /* Unfortunately most of these operations require root access
         * in one way or another */
        if (geteuid() != 0)
                return -EPERM;

        if ((r = running_in_chroot()) > 0) {
                if (id)
                        *id = "chroot";

                return r;
        }

        /* /proc/vz exists in container and outside of the container,
         * /proc/bc only outside of the container. */
        if (access("/proc/vz", F_OK) >= 0 &&
            access("/proc/bc", F_OK) < 0) {

                if (id)
                        *id = "openvz";

                return 1;
        }

        return detect_vm(id);
}

void execute_directory(const char *directory, DIR *d, char *argv[]) {
        DIR *_d = NULL;
        struct dirent *de;
        Hashmap *pids = NULL;

        assert(directory);

        /* Executes all binaries in a directory in parallel and waits
         * until all they all finished. */

        if (!d) {
                if (!(_d = opendir(directory))) {

                        if (errno == ENOENT)
                                return;

                        log_error("Failed to enumerate directory %s: %m", directory);
                        return;
                }

                d = _d;
        }

        if (!(pids = hashmap_new(trivial_hash_func, trivial_compare_func))) {
                log_error("Failed to allocate set.");
                goto finish;
        }

        while ((de = readdir(d))) {
                char *path;
                pid_t pid;
                int k;

                if (ignore_file(de->d_name))
                        continue;

                if (de->d_type != DT_REG &&
                    de->d_type != DT_LNK &&
                    de->d_type != DT_UNKNOWN)
                        continue;

                if (asprintf(&path, "%s/%s", directory, de->d_name) < 0) {
                        log_error("Out of memory");
                        continue;
                }

                if ((pid = fork()) < 0) {
                        log_error("Failed to fork: %m");
                        free(path);
                        continue;
                }

                if (pid == 0) {
                        char *_argv[2];
                        /* Child */

                        if (!argv) {
                                _argv[0] = path;
                                _argv[1] = NULL;
                                argv = _argv;
                        } else
                                if (!argv[0])
                                        argv[0] = path;

                        execv(path, argv);

                        log_error("Failed to execute %s: %m", path);
                        _exit(EXIT_FAILURE);
                }

                log_debug("Spawned %s as %lu", path, (unsigned long) pid);

                if ((k = hashmap_put(pids, UINT_TO_PTR(pid), path)) < 0) {
                        log_error("Failed to add PID to set: %s", strerror(-k));
                        free(path);
                }
        }

        while (!hashmap_isempty(pids)) {
                siginfo_t si;
                char *path;

                zero(si);
                if (waitid(P_ALL, 0, &si, WEXITED) < 0) {

                        if (errno == EINTR)
                                continue;

                        log_error("waitid() failed: %m");
                        goto finish;
                }

                if ((path = hashmap_remove(pids, UINT_TO_PTR(si.si_pid)))) {
                        if (!is_clean_exit(si.si_code, si.si_status)) {
                                if (si.si_code == CLD_EXITED)
                                        log_error("%s exited with exit status %i.", path, si.si_status);
                                else
                                        log_error("%s terminated by signal %s.", path, signal_to_string(si.si_status));
                        } else
                                log_debug("%s exited successfully.", path);

                        free(path);
                }
        }

finish:
        if (_d)
                closedir(_d);

        if (pids)
                hashmap_free_free(pids);
}

static const char *const ioprio_class_table[] = {
        [IOPRIO_CLASS_NONE] = "none",
        [IOPRIO_CLASS_RT] = "realtime",
        [IOPRIO_CLASS_BE] = "best-effort",
        [IOPRIO_CLASS_IDLE] = "idle"
};

DEFINE_STRING_TABLE_LOOKUP(ioprio_class, int);

static const char *const sigchld_code_table[] = {
        [CLD_EXITED] = "exited",
        [CLD_KILLED] = "killed",
        [CLD_DUMPED] = "dumped",
        [CLD_TRAPPED] = "trapped",
        [CLD_STOPPED] = "stopped",
        [CLD_CONTINUED] = "continued",
};

DEFINE_STRING_TABLE_LOOKUP(sigchld_code, int);

static const char *const log_facility_table[LOG_NFACILITIES] = {
        [LOG_FAC(LOG_KERN)] = "kern",
        [LOG_FAC(LOG_USER)] = "user",
        [LOG_FAC(LOG_MAIL)] = "mail",
        [LOG_FAC(LOG_DAEMON)] = "daemon",
        [LOG_FAC(LOG_AUTH)] = "auth",
        [LOG_FAC(LOG_SYSLOG)] = "syslog",
        [LOG_FAC(LOG_LPR)] = "lpr",
        [LOG_FAC(LOG_NEWS)] = "news",
        [LOG_FAC(LOG_UUCP)] = "uucp",
        [LOG_FAC(LOG_CRON)] = "cron",
        [LOG_FAC(LOG_AUTHPRIV)] = "authpriv",
        [LOG_FAC(LOG_FTP)] = "ftp",
        [LOG_FAC(LOG_LOCAL0)] = "local0",
        [LOG_FAC(LOG_LOCAL1)] = "local1",
        [LOG_FAC(LOG_LOCAL2)] = "local2",
        [LOG_FAC(LOG_LOCAL3)] = "local3",
        [LOG_FAC(LOG_LOCAL4)] = "local4",
        [LOG_FAC(LOG_LOCAL5)] = "local5",
        [LOG_FAC(LOG_LOCAL6)] = "local6",
        [LOG_FAC(LOG_LOCAL7)] = "local7"
};

DEFINE_STRING_TABLE_LOOKUP(log_facility, int);

static const char *const log_level_table[] = {
        [LOG_EMERG] = "emerg",
        [LOG_ALERT] = "alert",
        [LOG_CRIT] = "crit",
        [LOG_ERR] = "err",
        [LOG_WARNING] = "warning",
        [LOG_NOTICE] = "notice",
        [LOG_INFO] = "info",
        [LOG_DEBUG] = "debug"
};

DEFINE_STRING_TABLE_LOOKUP(log_level, int);

static const char* const sched_policy_table[] = {
        [SCHED_OTHER] = "other",
        [SCHED_BATCH] = "batch",
        [SCHED_IDLE] = "idle",
        [SCHED_FIFO] = "fifo",
        [SCHED_RR] = "rr"
};

DEFINE_STRING_TABLE_LOOKUP(sched_policy, int);

static const char* const rlimit_table[] = {
        [RLIMIT_CPU] = "LimitCPU",
        [RLIMIT_FSIZE] = "LimitFSIZE",
        [RLIMIT_DATA] = "LimitDATA",
        [RLIMIT_STACK] = "LimitSTACK",
        [RLIMIT_CORE] = "LimitCORE",
        [RLIMIT_RSS] = "LimitRSS",
        [RLIMIT_NOFILE] = "LimitNOFILE",
        [RLIMIT_AS] = "LimitAS",
        [RLIMIT_NPROC] = "LimitNPROC",
        [RLIMIT_MEMLOCK] = "LimitMEMLOCK",
        [RLIMIT_LOCKS] = "LimitLOCKS",
        [RLIMIT_SIGPENDING] = "LimitSIGPENDING",
        [RLIMIT_MSGQUEUE] = "LimitMSGQUEUE",
        [RLIMIT_NICE] = "LimitNICE",
        [RLIMIT_RTPRIO] = "LimitRTPRIO",
        [RLIMIT_RTTIME] = "LimitRTTIME"
};

DEFINE_STRING_TABLE_LOOKUP(rlimit, int);

static const char* const ip_tos_table[] = {
        [IPTOS_LOWDELAY] = "low-delay",
        [IPTOS_THROUGHPUT] = "throughput",
        [IPTOS_RELIABILITY] = "reliability",
        [IPTOS_LOWCOST] = "low-cost",
};

DEFINE_STRING_TABLE_LOOKUP(ip_tos, int);

static const char *const signal_table[] = {
        [SIGHUP] = "HUP",
        [SIGINT] = "INT",
        [SIGQUIT] = "QUIT",
        [SIGILL] = "ILL",
        [SIGTRAP] = "TRAP",
        [SIGABRT] = "ABRT",
        [SIGBUS] = "BUS",
        [SIGFPE] = "FPE",
        [SIGKILL] = "KILL",
        [SIGUSR1] = "USR1",
        [SIGSEGV] = "SEGV",
        [SIGUSR2] = "USR2",
        [SIGPIPE] = "PIPE",
        [SIGALRM] = "ALRM",
        [SIGTERM] = "TERM",
#ifdef SIGSTKFLT
        [SIGSTKFLT] = "STKFLT",  /* Linux on SPARC doesn't know SIGSTKFLT */
#endif
        [SIGCHLD] = "CHLD",
        [SIGCONT] = "CONT",
        [SIGSTOP] = "STOP",
        [SIGTSTP] = "TSTP",
        [SIGTTIN] = "TTIN",
        [SIGTTOU] = "TTOU",
        [SIGURG] = "URG",
        [SIGXCPU] = "XCPU",
        [SIGXFSZ] = "XFSZ",
        [SIGVTALRM] = "VTALRM",
        [SIGPROF] = "PROF",
        [SIGWINCH] = "WINCH",
        [SIGIO] = "IO",
        [SIGPWR] = "PWR",
        [SIGSYS] = "SYS"
};

DEFINE_STRING_TABLE_LOOKUP(signal, int);