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mirror of https://git.FreeBSD.org/src.git synced 2024-12-25 11:37:56 +00:00
freebsd/usr.bin/wall/wall.c
Eitan Adler 50e04779c4 Check the return error of set[e][ug]id. While this can never fail in the
current version of FreeBSD, this isn't guarenteed by the API.
Custom security modules, or future implementations of the setuid and
setgid may fail.

Submitted by:	Erik Cederstrand
Approved by:	cperciva
MFC after:	3 days
2012-10-22 03:07:05 +00:00

293 lines
7.1 KiB
C

/*
* 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.
* 4. 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1988, 1990, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif
#ifndef lint
static const char sccsid[] = "@(#)wall.c 8.2 (Berkeley) 11/16/93";
#endif
/*
* This program is not related to David Wall, whose Stanford Ph.D. thesis
* is entitled "Mechanisms for Broadcast and Selective Broadcast".
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <ctype.h>
#include <err.h>
#include <grp.h>
#include <locale.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include <wchar.h>
#include <wctype.h>
#include "ttymsg.h"
static void makemsg(char *);
static void usage(void);
static struct wallgroup {
struct wallgroup *next;
char *name;
gid_t gid;
} *grouplist;
static int nobanner;
static int mbufsize;
static char *mbuf;
static int
ttystat(char *line)
{
struct stat sb;
char ttybuf[MAXPATHLEN];
(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
if (stat(ttybuf, &sb) == 0) {
return (0);
} else
return (-1);
}
int
main(int argc, char *argv[])
{
struct iovec iov;
struct utmpx *utmp;
int ch;
int ingroup;
struct wallgroup *g;
struct group *grp;
char **np;
const char *p;
struct passwd *pw;
(void)setlocale(LC_CTYPE, "");
while ((ch = getopt(argc, argv, "g:n")) != -1)
switch (ch) {
case 'n':
/* undoc option for shutdown: suppress banner */
if (geteuid() == 0)
nobanner = 1;
break;
case 'g':
g = (struct wallgroup *)malloc(sizeof *g);
g->next = grouplist;
g->name = optarg;
g->gid = -1;
grouplist = g;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc > 1)
usage();
for (g = grouplist; g; g = g->next) {
grp = getgrnam(g->name);
if (grp != NULL)
g->gid = grp->gr_gid;
else
warnx("%s: no such group", g->name);
}
makemsg(*argv);
iov.iov_base = mbuf;
iov.iov_len = mbufsize;
/* NOSTRICT */
while ((utmp = getutxent()) != NULL) {
if (utmp->ut_type != USER_PROCESS)
continue;
if (ttystat(utmp->ut_line) != 0)
continue;
if (grouplist) {
ingroup = 0;
pw = getpwnam(utmp->ut_user);
if (!pw)
continue;
for (g = grouplist; g && ingroup == 0; g = g->next) {
if (g->gid == (gid_t)-1)
continue;
if (g->gid == pw->pw_gid)
ingroup = 1;
else if ((grp = getgrgid(g->gid)) != NULL) {
for (np = grp->gr_mem; *np; np++) {
if (strcmp(*np, utmp->ut_user) == 0) {
ingroup = 1;
break;
}
}
}
}
if (ingroup == 0)
continue;
}
if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
warnx("%s", p);
}
exit(0);
}
static void
usage(void)
{
(void)fprintf(stderr, "usage: wall [-g group] [file]\n");
exit(1);
}
void
makemsg(char *fname)
{
int cnt;
wchar_t ch;
struct tm *lt;
struct passwd *pw;
struct stat sbuf;
time_t now;
FILE *fp;
int fd;
char hostname[MAXHOSTNAMELEN], tmpname[64];
wchar_t *p, *tmp, lbuf[256], codebuf[13];
const char *tty;
const char *whom;
gid_t egid;
(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
err(1, "can't open temporary file");
(void)unlink(tmpname);
if (!nobanner) {
tty = ttyname(STDERR_FILENO);
if (tty == NULL)
tty = "no tty";
if (!(whom = getlogin()))
whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
(void)gethostname(hostname, sizeof(hostname));
(void)time(&now);
lt = localtime(&now);
/*
* 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)fwprintf(fp, L"\r%79s\r\n", " ");
(void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
L"Broadcast Message from %s@%s",
whom, hostname);
(void)fwprintf(fp, L"%-79.79S\007\007\r\n", lbuf);
(void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
L" (%s) at %d:%02d %s...", tty,
lt->tm_hour, lt->tm_min, lt->tm_zone);
(void)fwprintf(fp, L"%-79.79S\r\n", lbuf);
}
(void)fwprintf(fp, L"%79s\r\n", " ");
if (fname) {
egid = getegid();
setegid(getgid());
if (freopen(fname, "r", stdin) == NULL)
err(1, "can't read %s", fname);
if (setegid(egid) != 0)
err(1, "setegid failed");
}
cnt = 0;
while (fgetws(lbuf, sizeof(lbuf)/sizeof(wchar_t), stdin)) {
for (p = lbuf; (ch = *p) != L'\0'; ++p, ++cnt) {
if (ch == L'\r') {
putwc(L'\r', fp);
cnt = 0;
continue;
} else if (ch == L'\n') {
for (; cnt < 79; ++cnt)
putwc(L' ', fp);
putwc(L'\r', fp);
putwc(L'\n', fp);
break;
}
if (cnt == 79) {
putwc(L'\r', fp);
putwc(L'\n', fp);
cnt = 0;
}
if (iswprint(ch) || iswspace(ch) || ch == L'\a' || ch == L'\b') {
putwc(ch, fp);
} else {
(void)swprintf(codebuf, sizeof(codebuf)/sizeof(wchar_t), L"<0x%X>", ch);
for (tmp = codebuf; *tmp != L'\0'; ++tmp) {
putwc(*tmp, fp);
if (++cnt == 79) {
putwc(L'\r', fp);
putwc(L'\n', fp);
cnt = 0;
}
}
--cnt;
}
}
}
(void)fwprintf(fp, L"%79s\r\n", " ");
rewind(fp);
if (fstat(fd, &sbuf))
err(1, "can't stat temporary file");
mbufsize = sbuf.st_size;
if (!(mbuf = malloc((u_int)mbufsize)))
err(1, "out of memory");
if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
err(1, "can't read temporary file");
(void)close(fd);
}