lib/fileutils.c

   1 /*
   2  * Copyright (C) 2012 Sami Kerola <kerolasa@iki.fi>
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <sys/stat.h>
   8 #include <unistd.h>
   9 #include <sys/time.h>
  10 #include <sys/resource.h>
  11
  12 #include "c.h"
  13 #include "fileutils.h"
  14 #include "pathnames.h"
  15
  16 int mkstemp_cloexec(char *template)
  17 {
  18 #ifdef HAVE_MKOSTEMP
  19         return mkostemp(template, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC);
  20 #else
  21         int fd, old_flags, errno_save;
  22
  23         fd = mkstemp(template);
  24         if (fd < 0)
  25                 return fd;
  26
  27         old_flags = fcntl(fd, F_GETFD, 0);
  28         if (old_flags < 0)
  29                 goto unwind;
  30         if (fcntl(fd, F_SETFD, old_flags | O_CLOEXEC) < 0)
  31                 goto unwind;
  32
  33         return fd;
  34
  35 unwind:
  36         errno_save = errno;
  37         unlink(template);
  38         close(fd);
  39         errno = errno_save;
  40
  41         return -1;
  42 #endif
  43 }
  44
  45 /* Create open temporary file in safe way.  Please notice that the
  46  * file permissions are -rw------- by default. */
  47 int xmkstemp(char **tmpname, const char *dir, const char *prefix)
  48 {
  49         char *localtmp;
  50         const char *tmpenv;
  51         mode_t old_mode;
  52         int fd, rc;
  53
  54         /* Some use cases must be capable of being moved atomically
  55          * with rename(2), which is the reason why dir is here.  */
  56         tmpenv = dir ? dir : getenv("TMPDIR");
  57         if (!tmpenv)
  58                 tmpenv = _PATH_TMP;
  59
  60         rc = asprintf(&localtmp, "%s/%s.XXXXXX", tmpenv, prefix);
  61         if (rc < 0)
  62                 return -1;
  63
  64         old_mode = umask(077);
  65         fd = mkstemp_cloexec(localtmp);
  66         umask(old_mode);
  67         if (fd == -1) {
  68                 free(localtmp);
  69                 localtmp = NULL;
  70         }
  71         *tmpname = localtmp;
  72         return fd;
  73 }
  74
  75 int dup_fd_cloexec(int oldfd, int lowfd)
  76 {
  77         int fd, flags, errno_save;
  78
  79 #ifdef F_DUPFD_CLOEXEC
  80         fd = fcntl(oldfd, F_DUPFD_CLOEXEC, lowfd);
  81         if (fd >= 0)
  82                 return fd;
  83 #endif
  84
  85         fd = dup(oldfd);
  86         if (fd < 0)
  87                 return fd;
  88
  89         flags = fcntl(fd, F_GETFD);
  90         if (flags < 0)
  91                 goto unwind;
  92         if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0)
  93                 goto unwind;
  94
  95         return fd;
  96
  97 unwind:
  98         errno_save = errno;
  99         close(fd);
 100         errno = errno_save;
 101
 102         return -1;
 103 }
 104
 105 /*
 106  * portable getdtablesize()
 107  */
 108 int get_fd_tabsize(void)
 109 {
 110         int m;
 111
 112 #if defined(HAVE_GETDTABLESIZE)
 113         m = getdtablesize();
 114 #elif defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
 115         struct rlimit rl;
 116
 117         getrlimit(RLIMIT_NOFILE, &rl);
 118         m = rl.rlim_cur;
 119 #elif defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
 120         m = sysconf(_SC_OPEN_MAX);
 121 #else
 122         m = OPEN_MAX;
 123 #endif
 124         return m;
 125 }
 126
 127 #ifdef TEST_PROGRAM_FILEUTILS
 128 int main(void)
 129 {
 130         FILE *f;
 131         char *tmpname;
 132         f = xfmkstemp(&tmpname, NULL, "test");
 133         unlink(tmpname);
 134         free(tmpname);
 135         fclose(f);
 136         return EXIT_FAILURE;
 137 }
 138 #endif
 139
 140
 141 int mkdir_p(const char *path, mode_t mode)
 142 {
 143         char *p, *dir;
 144         int rc = 0;
 145
 146         if (!path || !*path)
 147                 return -EINVAL;
 148
 149         dir = p = strdup(path);
 150         if (!dir)
 151                 return -ENOMEM;
 152
 153         if (*p == '/')
 154                 p++;
 155
 156         while (p && *p) {
 157                 char *e = strchr(p, '/');
 158                 if (e)
 159                         *e = '\0';
 160                 if (*p) {
 161                         rc = mkdir(dir, mode);
 162                         if (rc && errno != EEXIST)
 163                                 break;
 164                         rc = 0;
 165                 }
 166                 if (!e)
 167                         break;
 168                 *e = '/';
 169                 p = e + 1;
 170         }
 171
 172         free(dir);
 173         return rc;
 174 }
 175
 176 /* returns basename and keeps dirname in the @path, if @path is "/" (root)
 177  * then returns empty string */
 178 char *stripoff_last_component(char *path)
 179 {
 180         char *p = path ? strrchr(path, '/') : NULL;
 181
 182         if (!p)
 183                 return NULL;
 184         *p = '\0';
 185         return p + 1;
 186 }