/* $NetBSD: comsat.c,v 1.25 2003/08/07 09:46:37 agc Exp $ */ /* * Copyright (c) 1980, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1980, 1993\n\ The Regents of the University of California. All rights reserved.\n"); #if 0 static char sccsid[] = "from: @(#)comsat.c 8.1 (Berkeley) 6/4/93"; #else __RCSID("$NetBSD: comsat.c,v 1.25 2003/08/07 09:46:37 agc Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int logging; int debug = 0; #define dsyslog if (debug) syslog #define MAXIDLE 120 char hostname[MAXHOSTNAMELEN+1]; struct utmp *utmp = NULL; time_t lastmsgtime; int nutmp, uf; void jkfprintf (FILE *, char[], off_t); void mailfor (char *); void notify (struct utmp *, off_t); void onalrm (int); void reapchildren (int); int main(int argc, char *argv[]) { struct sockaddr_storage from; int cc, ch; int fromlen; char msgbuf[100]; sigset_t nsigset; /* verify proper invocation */ fromlen = sizeof(from); if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) { (void)fprintf(stderr, "comsat: getsockname: %s.\n", strerror(errno)); exit(1); } openlog("comsat", LOG_PID, LOG_DAEMON); while ((ch = getopt(argc, argv, "l")) != -1) switch (ch) { case 'l': logging = 1; break; default: syslog(LOG_ERR, "Usage: %s [-l]", getprogname()); exit(1); } if (chdir(_PATH_MAILDIR)) { syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); exit(1); } if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) { syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); (void)recv(0, msgbuf, sizeof(msgbuf) - 1, 0); exit(1); } (void)time(&lastmsgtime); (void)gethostname(hostname, sizeof(hostname)); hostname[sizeof(hostname) - 1] = '\0'; onalrm(0); (void)signal(SIGALRM, onalrm); (void)signal(SIGTTOU, SIG_IGN); (void)signal(SIGCHLD, reapchildren); for (;;) { cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); if (cc <= 0) { if (errno != EINTR) sleep(1); errno = 0; continue; } if (!nutmp) /* no one has logged in yet */ continue; sigemptyset(&nsigset); sigaddset(&nsigset, SIGALRM); sigprocmask(SIG_SETMASK, &nsigset, NULL); msgbuf[cc] = '\0'; (void)time(&lastmsgtime); mailfor(msgbuf); sigemptyset(&nsigset); sigprocmask(SIG_SETMASK, &nsigset, NULL); } } void reapchildren(int signo) { while (wait3(NULL, WNOHANG, NULL) > 0); } void onalrm(int signo) { static u_int utmpsize; /* last malloced size for utmp */ static u_int utmpmtime; /* last modification time for utmp */ struct stat statbf; if (time(NULL) - lastmsgtime >= MAXIDLE) exit(0); (void)alarm((u_int)15); (void)fstat(uf, &statbf); if (statbf.st_mtime > utmpmtime) { utmpmtime = statbf.st_mtime; if (statbf.st_size > utmpsize) { utmpsize = statbf.st_size + 10 * sizeof(struct utmp); if ((utmp = realloc(utmp, utmpsize)) == NULL) { syslog(LOG_ERR, "%s", strerror(errno)); exit(1); } } (void)lseek(uf, (off_t)0, SEEK_SET); nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp); } } void mailfor(char *name) { struct utmp *utp = &utmp[nutmp]; char *cp, *fn; off_t offset; if (!(cp = strchr(name, '@'))) return; *cp = '\0'; errno = 0; offset = strtol(cp + 1, &fn, 10); if (errno == ERANGE) return; if (fn && *fn && *fn != '\n') { /* * Procmail sends messages to comsat with a trailing colon * and a pathname to the folder where the new message was * deposited. Since we can't reliably open only regular * files, we need to ignore these. With one exception: * if it mentions the user's system mailbox. */ char maildir[128]; int l = snprintf(maildir, sizeof(maildir), ":%s/%s", _PATH_MAILDIR, name); if (l > sizeof(maildir) || strcmp(maildir, fn) != 0) return; } while (--utp >= utmp) if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) notify(utp, offset); } static char *cr; void notify(struct utmp *utp, off_t offset) { FILE *tp; struct passwd *p; struct stat stb; struct termios ttybuf; char tty[20], name[sizeof(utmp[0].ut_name) + 1]; (void)snprintf(tty, sizeof(tty), "%s%.*s", _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { /* A slash is an attempt to break security... */ /* * XXX but what about something like "/dev/pts/5" * that we may one day "support". ? */ syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); return; } if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty); return; } dsyslog(LOG_DEBUG, "notify %s on %s", utp->ut_name, tty); if (fork()) return; (void)signal(SIGALRM, SIG_DFL); (void)alarm((u_int)30); if ((tp = fopen(tty, "w")) == NULL) { dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); _exit(1); } (void)tcgetattr(fileno(tp), &ttybuf); cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? "\n" : "\n\r"; (void)strlcpy(name, utp->ut_name, sizeof(name)); /* Set uid/gid/groups to users in case mail drop is on nfs */ if ((p = getpwnam(name)) == NULL || initgroups(p->pw_name, p->pw_gid) < 0 || setgid(p->pw_gid) < 0 || setuid(p->pw_uid) < 0) _exit(1); if (logging) syslog(LOG_INFO, "biff message for %s", name); (void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", cr, name, (int)sizeof(hostname), hostname, cr, cr); jkfprintf(tp, name, offset); (void)fclose(tp); _exit(0); } void jkfprintf(FILE *tp, char name[], off_t offset) { FILE *fi; int linecnt, charcnt, inheader; char line[BUFSIZ], visline[BUFSIZ*4], *nl; if ((fi = fopen(name, "r")) == NULL) return; (void)fseek(fi, offset, SEEK_SET); /* * Print the first 7 lines or 560 characters of the new mail * (whichever comes first). Skip header crap other than * From, Subject, To, and Date. */ linecnt = 7; charcnt = 560; inheader = 1; while (fgets(line, sizeof(line), fi) != NULL) { line[sizeof(line) - 1] = '\0'; if (inheader) { if (line[0] == '\n') { inheader = 0; continue; } if (line[0] == ' ' || line[0] == '\t' || (strncasecmp(line, "From:", 5) && strncasecmp(line, "Subject:", 8))) continue; } if (strncmp(line, "From ", 5) == 0) { (void)fprintf(tp, "----%s", cr); (void)fclose(fi); return; } if (linecnt <= 0 || charcnt <= 0) { (void)fprintf(tp, "...more...%s", cr); (void)fclose(fi); return; } if ((nl = strchr(line, '\n')) != NULL) *nl = '\0'; /* strip weird stuff so can't trojan horse stupid terminals */ (void)strvis(visline, line, VIS_CSTYLE); (void)fputs(visline, tp); (void)fputs(cr, tp); --linecnt; } (void)fprintf(tp, "----%s\n", cr); (void)fclose(fi); }