Edit
IABSD.fr/src/usr.bin/wall/wall.c
deraadt
- usr.bin/wall/wall.c
-
/* $OpenBSD: wall.c,v 1.34 2019/01/28 20:17:51 deraadt Exp $ */ /* $NetBSD: wall.c,v 1.6 1994/11/17 07:17:58 jtc Exp $ */ /* * Copyright (c) 1988, 1990, 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. */ /* * This program is not related to David Wall, whose Stanford Ph.D. thesis * is entitled "Mechanisms for Broadcast and Selective Broadcast". */ #include <sys/queue.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/uio.h> #include <ctype.h> #include <err.h> #include <grp.h> #include <limits.h> #include <paths.h> #include <pwd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <utmp.h> struct wallgroup { gid_t gid; char *name; char **mem; struct wallgroup *next; } *grouplist; struct utmptty { char *tty; SLIST_ENTRY(utmptty) next; }; void makemsg(char *); void addgroup(struct group *, char *); char *ttymsg(struct iovec *, int, char *, int); __dead void usage(void); static int isu8cont(unsigned char); int nobanner; int mbufsize; char *mbuf; /* ARGSUSED */ int main(int argc, char **argv) { FILE *fp; int ch, ingroup; struct iovec iov; struct utmp utmp; char *p, **mem; char line[sizeof(utmp.ut_line) + 1]; char username[sizeof(utmp.ut_name) + 1]; struct passwd *pw; struct group *grp; struct wallgroup *g; struct utmptty *un; SLIST_HEAD(,utmptty) utmphead; SLIST_INIT(&utmphead); while ((ch = getopt(argc, argv, "ng:")) != -1) switch (ch) { case 'n': /* undoc option for shutdown: suppress banner */ pw = getpwnam("nobody"); if (geteuid() == 0 || (pw && getuid() == pw->pw_uid)) nobanner = 1; break; case 'g': if ((grp = getgrnam(optarg)) == NULL) errx(1, "unknown group `%s'", optarg); addgroup(grp, optarg); break; default: usage(); } argc -= optind; argv += optind; if (argc > 1) usage(); makemsg(*argv); if (unveil(_PATH_UTMP, "r") == -1) err(1, "unveil"); if (unveil(_PATH_DEV, "w") == -1) err(1, "unveil"); if (unveil(_PATH_DEVDB, "r") == -1) err(1, "unveil"); if (pledge("stdio rpath wpath getpw proc", NULL) == -1) err(1, "pledge"); if (!(fp = fopen(_PATH_UTMP, "r"))) err(1, "cannot read %s", _PATH_UTMP); iov.iov_base = mbuf; iov.iov_len = mbufsize; while (fread(&utmp, sizeof(utmp), 1, fp) == 1) { if (!utmp.ut_name[0]) continue; if (grouplist) { ingroup = 0; strncpy(username, utmp.ut_name, sizeof(utmp.ut_name)); username[sizeof(utmp.ut_name)] = '\0'; pw = getpwnam(username); if (!pw) continue; for (g = grouplist; g && ingroup == 0; g = g->next) { if (g->gid == pw->pw_gid) ingroup = 1; for (mem = g->mem; *mem && ingroup == 0; mem++) if (strcmp(username, *mem) == 0) ingroup = 1; } if (ingroup == 0) continue; } strncpy(line, utmp.ut_line, sizeof(utmp.ut_line)); line[sizeof(utmp.ut_line)] = '\0'; un = malloc(sizeof(struct utmptty)); if (un == NULL) err(1, "malloc"); un->tty = strndup(line, sizeof(utmp.ut_line)); if (un->tty == NULL) err(1, "strndup"); SLIST_INSERT_HEAD(&utmphead, un, next); } fclose(fp); if (pledge("stdio rpath wpath proc", NULL) == -1) err(1, "pledge"); SLIST_FOREACH(un, &utmphead, next) { if ((p = ttymsg(&iov, 1, un->tty, 60*5)) != NULL) warnx("%s", p); } exit(0); } void makemsg(char *fname) { int cnt; struct tm *lt; struct passwd *pw; struct stat sbuf; time_t now; FILE *fp; int fd; char *p, *whom, hostname[HOST_NAME_MAX+1], lbuf[100], tmpname[PATH_MAX]; char *ttynam; unsigned char ch; snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXXXXXX", _PATH_TMP); if ((fd = mkstemp(tmpname)) >= 0) { (void)unlink(tmpname); fp = fdopen(fd, "r+"); } if (fd == -1 || fp == NULL) err(1, "can't open temporary file"); if (!nobanner) { if (!(whom = getlogin())) whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???"; (void)gethostname(hostname, sizeof(hostname)); (void)time(&now); lt = localtime(&now); if ((ttynam = ttyname(STDERR_FILENO)) == NULL) ttynam = "(not a tty)"; /* * all this stuff is to blank out a square for the message; * we wrap message lines at column 79, not 80, because some * terminals wrap after 79, some do not, and we can't tell. * Which means that we may leave a non-blank character * in column 80, but that can't be helped. */ (void)fprintf(fp, "\r%79s\r\n", " "); (void)snprintf(lbuf, sizeof lbuf, "Broadcast Message from %s@%s", whom, hostname); (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf); (void)snprintf(lbuf, sizeof lbuf, " (%s) at %d:%02d ...", ttynam, lt->tm_hour, lt->tm_min); (void)fprintf(fp, "%-79.79s\r\n", lbuf); } (void)fprintf(fp, "%79s\r\n", " "); if (fname) { gid_t egid = getegid(); setegid(getgid()); if (freopen(fname, "r", stdin) == NULL) err(1, "can't read %s", fname); setegid(egid); } while (fgets(lbuf, sizeof(lbuf), stdin)) for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) { if (cnt == 79 || ch == '\n') { for (; cnt < 79; ++cnt) putc(' ', fp); putc('\r', fp); putc('\n', fp); cnt = -1; } else if (!isu8cont(ch)) putc(isprint(ch) || isspace(ch) || ch == '\a' ? ch : '?', fp); } (void)fprintf(fp, "%79s\r\n", " "); rewind(fp); if (fstat(fd, &sbuf)) err(1, "can't stat temporary file"); mbufsize = sbuf.st_size; mbuf = malloc((u_int)mbufsize); if (mbuf == NULL) err(1, NULL); if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize) err(1, "can't read temporary file"); (void)close(fd); } void addgroup(struct group *grp, char *name) { int i; struct wallgroup *g; for (i = 0; grp->gr_mem[i]; i++) ; g = malloc(sizeof *g); if (g == NULL) err(1, NULL); g->gid = grp->gr_gid; g->name = name; g->mem = calloc(i + 1, sizeof(char *)); if (g->mem == NULL) err(1, NULL); for (i = 0; grp->gr_mem[i] != NULL; i++) { g->mem[i] = strdup(grp->gr_mem[i]); if (g->mem[i] == NULL) err(1, NULL); } g->mem[i] = NULL; g->next = grouplist; grouplist = g; } void usage(void) { extern char *__progname; (void)fprintf(stderr, "usage: %s [-g group] [file]\n", __progname); exit(1); } static int isu8cont(unsigned char c) { return (c & (0x80 | 0x40)) == 0x80; }