int
main(int argc, char *argv[])
{
char tty[PATH_MAX], *mytty, *cp;
int msgsok, myttyfd;
time_t atime;
uid_t myuid;
/* check that sender has write enabled */
if (isatty(fileno(stdin)))
myttyfd = fileno(stdin);
else if (isatty(fileno(stdout)))
myttyfd = fileno(stdout);
else if (isatty(fileno(stderr)))
myttyfd = fileno(stderr);
else
errx(1, "can't find your tty");
if (!(mytty = ttyname(myttyfd)))
errx(1, "can't find your tty's name");
if ((cp = strrchr(mytty, '/')))
mytty = cp + 1;
if (term_chk(mytty, &msgsok, &atime, 1))
exit(1);
if (!msgsok)
warnx("you have write permission turned off");
myuid = getuid();
/* check args */
switch (argc) {
case 2:
search_utmp(argv[1], tty, sizeof tty, mytty, myuid);
do_write(tty, mytty, myuid);
break;
case 3:
if (!strncmp(argv[2], _PATH_DEV, sizeof(_PATH_DEV) - 1))
argv[2] += sizeof(_PATH_DEV) - 1;
if (utmp_chk(argv[1], argv[2]))
errx(1, "%s is not logged in on %s",
argv[1], argv[2]);
if (term_chk(argv[2], &msgsok, &atime, 1))
exit(1);
if (myuid && !msgsok)
errx(1, "%s has messages disabled on %s",
argv[1], argv[2]);
do_write(argv[2], mytty, myuid);
break;
default:
(void)fprintf(stderr, "usage: write user [ttyname]\n");
exit(1);
}
done(0);
/* NOTREACHED */
return (0);
}
int
main(int argc, char **argv)
{
time_t atime;
uid_t myuid;
int msgsok, mymsgok, myttyfd;
char tty[MAXPATHLEN], *mytty;
setlocale(LC_CTYPE, "");
/* check that sender has write enabled */
if (isatty(fileno(stdin)))
myttyfd = fileno(stdin);
else if (isatty(fileno(stdout)))
myttyfd = fileno(stdout);
else if (isatty(fileno(stderr)))
myttyfd = fileno(stderr);
else
errx(1, "can't find your tty");
if (!(mytty = ttyname(myttyfd)))
errx(1, "can't find your tty's name");
if (!strncmp(mytty, _PATH_DEV, strlen(_PATH_DEV)))
mytty += strlen(_PATH_DEV);
if (term_chk(mytty, &mymsgok, &atime, 1))
exit(1);
if (!mymsgok)
warnx("you have write permission turned off (man mesg)");
myuid = getuid();
/* check args */
switch (argc) {
case 2:
search_utmp(argv[1], tty, sizeof tty, mytty, myuid);
do_write(tty, mytty, myuid, &mymsgok);
break;
case 3:
if (!strncmp(argv[2], _PATH_DEV, strlen(_PATH_DEV)))
argv[2] += strlen(_PATH_DEV);
if (utmp_chk(argv[1], argv[2]))
errx(1, "%s is not logged in on %s", argv[1], argv[2]);
if (term_chk(argv[2], &msgsok, &atime, 1))
exit(1);
if (myuid && !msgsok)
errx(1, "%s has messages disabled on %s", argv[1], argv[2]);
do_write(argv[2], mytty, myuid, &mymsgok);
break;
default:
usage();
}
done(0);
return (0);
}
char *
check_sender(time_t *atime, uid_t myuid, gid_t saved_egid)
{
int myttyfd;
int msgsok;
char *mytty;
/* check that sender has write enabled */
if (isatty(fileno(stdin)))
myttyfd = fileno(stdin);
else if (isatty(fileno(stdout)))
myttyfd = fileno(stdout);
else if (isatty(fileno(stderr)))
myttyfd = fileno(stderr);
else if (atime == NULL)
return NULL;
else
errx(1, "Cannot find your tty");
if ((mytty = ttyname(myttyfd)) == NULL)
err(1, "Cannot find the name of your tty");
if (strncmp(mytty, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
mytty += sizeof(_PATH_DEV) - 1;
if (term_chk(myuid, mytty, &msgsok, atime, 1, saved_egid) == -1)
err(1, "%s%s", _PATH_DEV, mytty);
if (!msgsok) {
warnx(
"You have write permission turned off; no reply possible");
}
return mytty;
}
/*
* search_utmp - search utmp for the "best" terminal to write to
*
* Ignores terminals with messages disabled, and of the rest, returns
* the one with the most recent access time. Returns as value the number
* of the user's terminals with messages enabled, or -1 if the user is
* not logged in at all.
*
* Special case for writing to yourself - ignore the terminal you're
* writing from, unless that's the only terminal with messages enabled.
*/
void
search_utmp(char *user, char *tty, int ttyl, char *mytty, uid_t myuid)
{
struct utmp u;
time_t bestatime, atime;
int ufd, nloggedttys, nttys, msgsok, user_is_me;
char atty[UT_LINESIZE + 1];
if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
err(1, "%s", _PATH_UTMP);
nloggedttys = nttys = 0;
bestatime = 0;
user_is_me = 0;
while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
++nloggedttys;
(void)strncpy(atty, u.ut_line, UT_LINESIZE);
atty[UT_LINESIZE] = '\0';
if (term_chk(atty, &msgsok, &atime, 0))
continue; /* bad term? skip */
if (myuid && !msgsok)
continue; /* skip ttys with msgs off */
if (strcmp(atty, mytty) == 0) {
user_is_me = 1;
continue; /* don't write to yourself */
}
++nttys;
if (atime > bestatime) {
bestatime = atime;
(void)strlcpy(tty, atty, ttyl);
}
}
(void)close(ufd);
if (nloggedttys == 0)
errx(1, "%s is not logged in", user);
if (nttys == 0) {
if (user_is_me) { /* ok, so write to yourself! */
(void)strlcpy(tty, mytty, ttyl);
return;
}
errx(1, "%s has messages disabled", user);
} else if (nttys > 1)
warnx("%s is logged in more than once; writing to %s",
user, tty);
}
/*
* search_utmp - search utmp for the "best" terminal to write to
*
* Ignores terminals with messages disabled, and of the rest, returns
* the one with the most recent access time. Returns as value the number
* of the user's terminals with messages enabled, or -1 if the user is
* not logged in at all.
*
* 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(const char *user, char *tty, size_t ttyl, const char *mytty, uid_t myuid)
{
struct utmpentry *ep;
time_t bestatime, atime;
int nloggedttys, nttys, msgsok, user_is_me;
getutentries(NULL, &ep);
nloggedttys = nttys = 0;
bestatime = 0;
user_is_me = 0;
for (; ep; ep = ep->next)
if (strcmp(user, ep->name) == 0) {
++nloggedttys;
if (term_chk(ep->line, &msgsok, &atime, 0))
continue; /* bad term? skip */
if (myuid && !msgsok)
continue; /* skip ttys with msgs off */
if (strcmp(ep->line, mytty) == 0) {
user_is_me = 1;
continue; /* don't write to yourself */
}
++nttys;
if (atime > bestatime) {
bestatime = atime;
strlcpy(tty, ep->line, ttyl);
}
}
if (nloggedttys == 0)
errx(1, "%s is not logged in", user);
if (nttys == 0) {
if (user_is_me) { /* ok, so write to yourself! */
strlcpy(tty, mytty, ttyl);
return;
}
errx(1, "%s has messages disabled", user);
} else if (nttys > 1) {
warnx("%s is logged in more than once; writing to %s", user, tty);
}
}
