*
*/
-#include <stdio.h>
-#include <unistd.h>
-#include <utmp.h>
#include <errno.h>
-#include <time.h>
+#include <getopt.h>
+#include <paths.h>
#include <pwd.h>
-#include <string.h>
-#include <stdlib.h>
#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
-#include <paths.h>
-#include <getopt.h>
+#include <time.h>
+#include <unistd.h>
+#include <utmpx.h>
#include "c.h"
#include "carefulputc.h"
#include "closestream.h"
#include "nls.h"
#include "strutils.h"
+#include "ttyutils.h"
#include "xalloc.h"
-static void __attribute__ ((__noreturn__)) usage(FILE * out)
+static sig_atomic_t signal_received = 0;
+
+struct write_control {
+ uid_t src_uid;
+ const char *src_login;
+ const char *src_tty_path;
+ const char *src_tty_name;
+ const char *dst_login;
+ char *dst_tty_path;
+ const char *dst_tty_name;
+};
+
+static void __attribute__((__noreturn__)) usage(void)
{
+ FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] <user> [<ttyname>]\n"),
fputs(_("Send a message to another user.\n"), out);
fputs(USAGE_OPTIONS, out);
- fputs(USAGE_HELP, out);
- fputs(USAGE_VERSION, out);
-
- fprintf(out, USAGE_MAN_TAIL("write(1)"));
- exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+ printf(USAGE_HELP_OPTIONS(16));
+ printf(USAGE_MAN_TAIL("write(1)"));
+ exit(EXIT_SUCCESS);
}
/*
- * term_chk - check that a terminal exists, and get the message bit
+ * check_tty - check that a terminal exists, and get the message bit
* and the access time
*/
-static int term_chk(char *tty, int *msgsokP, time_t * atimeP, int showerror)
+static int check_tty(const char *tty, int *tty_writeable, time_t *tty_atime, int showerror)
{
struct stat s;
- char path[PATH_MAX];
- if (strlen(tty) + 6 > sizeof(path))
- return 1;
- sprintf(path, "/dev/%s", tty);
- if (stat(path, &s) < 0) {
+ if (stat(tty, &s) < 0) {
if (showerror)
- warn("%s", path);
+ warn("%s", tty);
return 1;
}
if (getuid() == 0) /* root can always write */
- *msgsokP = 1;
- else
- *msgsokP = (s.st_mode & S_IWGRP) && (getegid() == s.st_gid);
- if (atimeP)
- *atimeP = s.st_atime;
+ *tty_writeable = 1;
+ else {
+ if (getegid() != s.st_gid) {
+ warnx(_("effective gid does not match group of %s"), tty);
+ return 1;
+ }
+ *tty_writeable = s.st_mode & S_IWGRP;
+ }
+ if (tty_atime)
+ *tty_atime = s.st_atime;
return 0;
}
/*
- * utmp_chk - checks that the given user is actually logged in on
+ * check_utmp - checks that the given user is actually logged in on
* the given tty
*/
-static int utmp_chk(char *user, char *tty)
+static int check_utmp(const struct write_control *ctl)
{
- struct utmp u;
- struct utmp *uptr;
+ struct utmpx *u;
int res = 1;
- utmpname(_PATH_UTMP);
- setutent();
+ utmpxname(_PATH_UTMP);
+ setutxent();
- while ((uptr = getutent())) {
- memcpy(&u, uptr, sizeof(u));
- if (strncmp(user, u.ut_user, sizeof(u.ut_user)) == 0 &&
- strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
+ while ((u = getutxent())) {
+ if (strncmp(ctl->dst_login, u->ut_user, sizeof(u->ut_user)) == 0 &&
+ strncmp(ctl->dst_tty_name, u->ut_line, sizeof(u->ut_line)) == 0) {
res = 0;
break;
}
}
- endutent();
+ endutxent();
return res;
}
* Special case for writing to yourself - ignore the terminal you're
* writing from, unless that's the only terminal with messages enabled.
*/
-static void search_utmp(char *user, char *tty, char *mytty, uid_t myuid)
+static void search_utmp(struct write_control *ctl)
{
- struct utmp u;
- struct utmp *uptr;
- time_t bestatime, atime;
- int nloggedttys, nttys, msgsok = 0, user_is_me;
- char atty[sizeof(u.ut_line) + 1];
-
- utmpname(_PATH_UTMP);
- setutent();
-
- nloggedttys = nttys = 0;
- bestatime = 0;
- user_is_me = 0;
- while ((uptr = getutent())) {
- memcpy(&u, uptr, sizeof(u));
- if (strncmp(user, u.ut_user, sizeof(u.ut_user)) == 0) {
- ++nloggedttys;
- xstrncpy(atty, u.ut_line, sizeof(atty));
- if (term_chk(atty, &msgsok, &atime, 0))
- /* bad term? skip */
- continue;
- if (myuid && !msgsok)
- /* skip ttys with msgs off */
- continue;
- if (strcmp(atty, mytty) == 0) {
- user_is_me = 1;
- /* don't write to yourself */
- continue;
- }
- if (u.ut_type != USER_PROCESS)
- /* it's not a valid entry */
- continue;
- ++nttys;
- if (atime > bestatime) {
- bestatime = atime;
- strcpy(tty, atty);
- }
+ struct utmpx *u;
+ time_t best_atime = 0, tty_atime;
+ int num_ttys = 0, valid_ttys = 0, tty_writeable = 0, user_is_me = 0;
+ char path[sizeof(u->ut_line) + 6];
+
+ utmpxname(_PATH_UTMP);
+ setutxent();
+
+ while ((u = getutxent())) {
+ if (strncmp(ctl->dst_login, u->ut_user, sizeof(u->ut_user)) != 0)
+ continue;
+ num_ttys++;
+ sprintf(path, "/dev/%s", u->ut_line);
+ if (check_tty(path, &tty_writeable, &tty_atime, 0))
+ /* bad term? skip */
+ continue;
+ if (ctl->src_uid && !tty_writeable)
+ /* skip ttys with msgs off */
+ continue;
+ if (strcmp(u->ut_line, ctl->src_tty_name) == 0) {
+ user_is_me = 1;
+ /* don't write to yourself */
+ continue;
+ }
+ if (u->ut_type != USER_PROCESS)
+ /* it's not a valid entry */
+ continue;
+ valid_ttys++;
+ if (best_atime < tty_atime) {
+ best_atime = tty_atime;
+ free(ctl->dst_tty_path);
+ ctl->dst_tty_path = xstrdup(path);
+ ctl->dst_tty_name = ctl->dst_tty_path + 5;
}
}
- endutent();
- if (nloggedttys == 0)
- errx(EXIT_FAILURE, _("%s is not logged in"), user);
- if (nttys == 0) {
+ endutxent();
+ if (num_ttys == 0)
+ errx(EXIT_FAILURE, _("%s is not logged in"), ctl->dst_login);
+ if (valid_ttys == 0) {
if (user_is_me) {
/* ok, so write to yourself! */
- strcpy(tty, mytty);
+ if (!ctl->src_tty_path)
+ errx(EXIT_FAILURE, _("can't find your tty's name"));
+ ctl->dst_tty_path = xstrdup(ctl->src_tty_path);
+ ctl->dst_tty_name = ctl->dst_tty_path + 5;
return;
}
- errx(EXIT_FAILURE, _("%s has messages disabled"), user);
- } else if (nttys > 1) {
- warnx(_("%s is logged in more than once; writing to %s"),
- user, tty);
+ errx(EXIT_FAILURE, _("%s has messages disabled"), ctl->dst_login);
}
+ if (1 < valid_ttys)
+ warnx(_("%s is logged in more than once; writing to %s"),
+ ctl->dst_login, ctl->dst_tty_name);
}
/*
- * done - cleanup and exit
+ * signal_handler - cause write loop to exit
*/
-static void __attribute__ ((__noreturn__))
- done(int dummy __attribute__ ((__unused__)))
+static void signal_handler(int signo)
{
- printf("EOF\r\n");
- _exit(EXIT_SUCCESS);
+ signal_received = signo;
}
/*
- * wr_fputs - like fputs(), but makes control characters visible and
+ * write_line - like fputs(), but makes control characters visible and
* turns \n into \r\n.
*/
-static void wr_fputs(char *s)
+static void write_line(char *s)
{
- char c;
-
-#define PUTC(c) if (fputc_careful(c, stdout, '^') == EOF) \
- err(EXIT_FAILURE, _("carefulputc failed"));
while (*s) {
- c = *s++;
- if (c == '\n')
- PUTC('\r');
- PUTC(c);
+ const int c = *s++;
+
+ if ((c == '\n' && fputc_careful('\r', stdout, '^') == EOF)
+ || fputc_careful(c, stdout, '^') == EOF)
+ err(EXIT_FAILURE, _("carefulputc failed"));
}
- return;
-#undef PUTC
}
/*
* do_write - actually make the connection
*/
-static void do_write(char *tty, char *mytty, uid_t myuid)
+static void do_write(const struct write_control *ctl)
{
- char *login, *pwuid, *nows;
+ char *login, *pwuid;
struct passwd *pwd;
time_t now;
- char path[PATH_MAX], *host, line[512];
+ struct tm *tm;
+ char *host, line[512];
+ struct sigaction sigact;
/* Determine our login name(s) before the we reopen() stdout */
- if ((pwd = getpwuid(myuid)) != NULL)
+ if ((pwd = getpwuid(ctl->src_uid)) != NULL)
pwuid = pwd->pw_name;
else
pwuid = "???";
if ((login = getlogin()) == NULL)
login = pwuid;
- if (strlen(tty) + 6 > sizeof(path))
- errx(EXIT_FAILURE, _("tty path %s too long"), tty);
- snprintf(path, sizeof(path), "/dev/%s", tty);
- if ((freopen(path, "w", stdout)) == NULL)
- err(EXIT_FAILURE, "%s", path);
+ if ((freopen(ctl->dst_tty_path, "w", stdout)) == NULL)
+ err(EXIT_FAILURE, "%s", ctl->dst_tty_path);
- signal(SIGINT, done);
- signal(SIGHUP, done);
+ sigact.sa_handler = signal_handler;
+ sigemptyset(&sigact.sa_mask);
+ sigact.sa_flags = 0;
+ sigaction(SIGINT, &sigact, NULL);
+ sigaction(SIGHUP, &sigact, NULL);
- /* print greeting */
host = xgethostname();
if (!host)
host = xstrdup("???");
- now = time((time_t *) NULL);
- nows = ctime(&now);
- nows[16] = '\0';
- printf("\r\n\007\007\007");
+ now = time((time_t *)NULL);
+ tm = localtime(&now);
+ /* print greeting */
+ printf("\r\n\a\a\a");
if (strcmp(login, pwuid))
- printf(_("Message from %s@%s (as %s) on %s at %s ..."),
- login, host, pwuid, mytty, nows + 11);
+ printf(_("Message from %s@%s (as %s) on %s at %02d:%02d ..."),
+ login, host, pwuid, ctl->src_tty_name,
+ tm->tm_hour, tm->tm_min);
else
- printf(_("Message from %s@%s on %s at %s ..."),
- login, host, mytty, nows + 11);
+ printf(_("Message from %s@%s on %s at %02d:%02d ..."),
+ login, host, ctl->src_tty_name,
+ tm->tm_hour, tm->tm_min);
free(host);
printf("\r\n");
- while (fgets(line, sizeof(line), stdin) != NULL)
- wr_fputs(line);
+ while (fgets(line, sizeof(line), stdin) != NULL) {
+ if (signal_received)
+ break;
+ write_line(line);
+ }
+ printf("EOF\r\n");
}
int main(int argc, char **argv)
{
- uid_t myuid;
- int msgsok = 0, myttyfd, c;
- char tty[PATH_MAX], *mytty;
+ int tty_writeable = 0, c;
+ struct write_control ctl = { 0 };
static const struct option longopts[] = {
{"version", no_argument, NULL, 'V'},
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'h':
- usage(stdout);
+ usage();
default:
- usage(stderr);
+ errtryhelp(EXIT_FAILURE);
}
- /* check that sender has write enabled */
- if (isatty(STDIN_FILENO))
- myttyfd = STDIN_FILENO;
- else if (isatty(STDOUT_FILENO))
- myttyfd = STDOUT_FILENO;
- else if (isatty(STDERR_FILENO))
- myttyfd = STDERR_FILENO;
- else
- myttyfd = -1;
-
- if (myttyfd != -1) {
- if (!(mytty = ttyname(myttyfd)))
- errx(EXIT_FAILURE,
- _("can't find your tty's name"));
-
- /*
- * We may have /dev/ttyN but also /dev/pts/xx. Below,
- * term_chk() will put "/dev/" in front, so remove that
- * part.
- */
- if (!strncmp(mytty, "/dev/", 5))
- mytty += 5;
- if (term_chk(mytty, &msgsok, NULL, 1))
+ if (get_terminal_name(&ctl.src_tty_path, &ctl.src_tty_name, NULL) == 0) {
+ /* check that sender has write enabled */
+ if (check_tty(ctl.src_tty_path, &tty_writeable, NULL, 1))
exit(EXIT_FAILURE);
- if (!msgsok)
+ if (!tty_writeable)
errx(EXIT_FAILURE,
_("you have write permission turned off"));
- msgsok = 0;
+ tty_writeable = 0;
} else
- mytty = "<no tty>";
+ ctl.src_tty_name = "<no tty>";
- myuid = getuid();
+ ctl.src_uid = getuid();
/* check args */
switch (argc) {
case 2:
- search_utmp(argv[1], tty, mytty, myuid);
- do_write(tty, mytty, myuid);
+ ctl.dst_login = argv[1];
+ search_utmp(&ctl);
+ do_write(&ctl);
break;
case 3:
+ ctl.dst_login = argv[1];
if (!strncmp(argv[2], "/dev/", 5))
- argv[2] += 5;
- if (utmp_chk(argv[1], argv[2]))
+ ctl.dst_tty_path = xstrdup(argv[2]);
+ else
+ xasprintf(&ctl.dst_tty_path, "/dev/%s", argv[2]);
+ ctl.dst_tty_name = ctl.dst_tty_path + 5;
+ if (check_utmp(&ctl))
errx(EXIT_FAILURE,
_("%s is not logged in on %s"),
- argv[1], argv[2]);
- if (term_chk(argv[2], &msgsok, NULL, 1))
+ ctl.dst_login, ctl.dst_tty_name);
+ if (check_tty(ctl.dst_tty_path, &tty_writeable, NULL, 1))
exit(EXIT_FAILURE);
- if (myuid && !msgsok)
+ if (ctl.src_uid && !tty_writeable)
errx(EXIT_FAILURE,
_("%s has messages disabled on %s"),
- argv[1], argv[2]);
- do_write(argv[2], mytty, myuid);
+ ctl.dst_login, ctl.dst_tty_name);
+ do_write(&ctl);
break;
default:
- usage(stderr);
+ errtryhelp(EXIT_FAILURE);
}
-
- done(0);
- /* NOTREACHED */
- return EXIT_FAILURE;
+ free(ctl.dst_tty_path);
+ return EXIT_SUCCESS;
}
projects / thirdparty / util-linux.git / blobdiff