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util-linux/term-utils/wall.c

450 lines
11 KiB

/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*
* Modified Sun Mar 12 10:34:34 1995, faith@cs.unc.edu, for Linux
*/
/*
* This program is not related to David Wall, whose Stanford Ph.D. thesis
* is entitled "Mechanisms for Broadcast and Selective Broadcast".
*
* 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <errno.h>
#include <paths.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include <getopt.h>
#include <sys/types.h>
#include <grp.h>
#include "nls.h"
#include "xalloc.h"
#include "strutils.h"
#include "ttymsg.h"
#include "pathnames.h"
#include "carefulputc.h"
#include "c.h"
#include "cctype.h"
#include "fileutils.h"
#include "closestream.h"
#include "timeutils.h"
#define TERM_WIDTH 79
#define WRITE_TIME_OUT 300 /* in seconds */
/* Function prototypes */
static char *makemsg(char *fname, char **mvec, int mvecsz,
size_t *mbufsize, int print_banner);
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] [<file> | <message>]\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Write a message to all users.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -g, --group <group> only send message to group\n"), out);
fputs(_(" -n, --nobanner do not print banner, works only for root\n"), out);
fputs(_(" -t, --timeout <timeout> write timeout in seconds\n"), out);
fputs(USAGE_SEPARATOR, out);
printf(USAGE_HELP_OPTIONS(25));
printf(USAGE_MAN_TAIL("wall(1)"));
exit(EXIT_SUCCESS);
}
struct group_workspace {
gid_t requested_group;
int ngroups;
/* getgrouplist() on OSX takes int* not gid_t* */
#ifdef __APPLE__
int *groups;
#else
gid_t *groups;
#endif
};
static gid_t get_group_gid(const char *group)
{
struct group *gr;
gid_t gid;
if ((gr = getgrnam(group)))
return gr->gr_gid;
gid = strtou32_or_err(group, _("invalid group argument"));
if (!getgrgid(gid))
errx(EXIT_FAILURE, _("%s: unknown gid"), group);
return gid;
}
static struct group_workspace *init_group_workspace(const char *group)
{
struct group_workspace *buf = xmalloc(sizeof(struct group_workspace));
buf->requested_group = get_group_gid(group);
buf->ngroups = sysconf(_SC_NGROUPS_MAX) + 1; /* room for the primary gid */
buf->groups = xcalloc(sizeof(*buf->groups), buf->ngroups);
return buf;
}
static void free_group_workspace(struct group_workspace *buf)
{
if (!buf)
return;
free(buf->groups);
free(buf);
}
static int is_gr_member(const char *login, const struct group_workspace *buf)
{
struct passwd *pw;
int ngroups = buf->ngroups;
int rc;
pw = getpwnam(login);
if (!pw)
return 0;
if (buf->requested_group == pw->pw_gid)
return 1;
rc = getgrouplist(login, pw->pw_gid, buf->groups, &ngroups);
if (rc < 0) {
/* buffer too small, not sure how this can happen, since
we used sysconf to get the size... */
errx(EXIT_FAILURE,
_("getgrouplist found more groups than sysconf allows"));
}
for (; ngroups >= 0; --ngroups) {
if (buf->requested_group == (gid_t) buf->groups[ngroups])
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
int ch;
struct iovec iov;
struct utmpx *utmpptr;
char *p;
char line[sizeof(utmpptr->ut_line) + 1];
int print_banner = TRUE;
struct group_workspace *group_buf = NULL;
char *mbuf, *fname = NULL;
size_t mbufsize;
unsigned timeout = WRITE_TIME_OUT;
char **mvec = NULL;
int mvecsz = 0;
static const struct option longopts[] = {
{ "nobanner", no_argument, NULL, 'n' },
{ "timeout", required_argument, NULL, 't' },
{ "group", required_argument, NULL, 'g' },
{ "version", no_argument, NULL, 'V' },
{ "help", no_argument, NULL, 'h' },
{ NULL, 0, NULL, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
close_stdout_atexit();
while ((ch = getopt_long(argc, argv, "nt:g:Vh", longopts, NULL)) != -1) {
switch (ch) {
case 'n':
if (geteuid() == 0)
print_banner = FALSE;
else
warnx(_("--nobanner is available only for root"));
break;
case 't':
timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
if (timeout < 1)
errx(EXIT_FAILURE, _("invalid timeout argument: %s"), optarg);
break;
case 'g':
group_buf = init_group_workspace(optarg);
break;
case 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
errtryhelp(EXIT_FAILURE);
}
}
argc -= optind;
argv += optind;
if (argc == 1 && access(argv[0], F_OK) == 0)
fname = argv[0];
else if (argc >= 1) {
mvec = argv;
mvecsz = argc;
}
mbuf = makemsg(fname, mvec, mvecsz, &mbufsize, print_banner);
iov.iov_base = mbuf;
iov.iov_len = mbufsize;
while((utmpptr = getutxent())) {
if (!utmpptr->ut_user[0])
continue;
#ifdef USER_PROCESS
if (utmpptr->ut_type != USER_PROCESS)
continue;
#endif
/* Joey Hess reports that use-sessreg in /etc/X11/wdm/ produces
* ut_line entries like :0, and a write to /dev/:0 fails.
*
* It also seems that some login manager may produce empty ut_line.
*/
if (!*utmpptr->ut_line || *utmpptr->ut_line == ':')
continue;
if (group_buf && !is_gr_member(utmpptr->ut_user, group_buf))
continue;
mem2strcpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line), sizeof(line));
if ((p = ttymsg(&iov, 1, line, timeout)) != NULL)
warnx("%s", p);
}
endutxent();
free(mbuf);
free_group_workspace(group_buf);
exit(EXIT_SUCCESS);
}
struct buffer {
size_t sz;
size_t used;
char *data;
};
static void buf_enlarge(struct buffer *bs, size_t len)
{
if (bs->sz == 0 || len > bs->sz - bs->used) {
bs->sz += len < 128 ? 128 : len;
bs->data = xrealloc(bs->data, bs->sz);
}
}
static void buf_puts(struct buffer *bs, const char *s)
{
size_t len = strlen(s);
buf_enlarge(bs, len + 1);
memcpy(bs->data + bs->used, s, len + 1);
bs->used += len;
}
static void buf_printf(struct buffer *bs, const char *fmt, ...)
{
int rc;
va_list ap;
size_t limit;
buf_enlarge(bs, 0); /* default size */
limit = bs->sz - bs->used;
va_start(ap, fmt);
rc = vsnprintf(bs->data + bs->used, limit, fmt, ap);
va_end(ap);
if (rc >= 0 && (size_t) rc >= limit) { /* not enough, enlarge */
buf_enlarge(bs, (size_t)rc + 1);
limit = bs->sz - bs->used;
va_start(ap, fmt);
rc = vsnprintf(bs->data + bs->used, limit, fmt, ap);
va_end(ap);
}
if (rc > 0)
bs->used += rc;
}
static void buf_putc_careful(struct buffer *bs, int c)
{
if (isprint(c) || c == '\a' || c == '\t' || c == '\r' || c == '\n') {
buf_enlarge(bs, 1);
bs->data[bs->used++] = c;
} else if (!c_isascii(c))
buf_printf(bs, "\\%3o", (unsigned char)c);
else {
char tmp[] = { '^', c ^ 0x40, '\0' };
buf_puts(bs, tmp);
}
}
static char *makemsg(char *fname, char **mvec, int mvecsz,
size_t *mbufsize, int print_banner)
{
struct buffer _bs = {.used = 0}, *bs = &_bs;
register int ch, cnt;
char *p, *lbuf;
long line_max;
line_max = sysconf(_SC_LINE_MAX);
if (line_max <= 0)
line_max = 512;
lbuf = xmalloc(line_max);
if (print_banner == TRUE) {
char *hostname = xgethostname();
char *whom, *where, date[CTIME_BUFSIZ];
struct passwd *pw;
time_t now;
if (!(whom = getlogin()) || !*whom)
whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
if (!whom) {
whom = "someone";
warn(_("cannot get passwd uid"));
}
where = ttyname(STDOUT_FILENO);
if (!where) {
where = "somewhere";
} else if (strncmp(where, "/dev/", 5) == 0)
where += 5;
time(&now);
ctime_r(&now, date);
date[strlen(date) - 1] = '\0';
/*
* 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.
*/
/* snprintf is not always available, but the sprintf's here
will not overflow as long as %d takes at most 100 chars */
buf_printf(bs, "\r%*s\r\n", TERM_WIDTH, " ");
snprintf(lbuf, line_max,
_("Broadcast message from %s@%s (%s) (%s):"),
whom, hostname, where, date);
buf_printf(bs, "%-*.*s\007\007\r\n", TERM_WIDTH, TERM_WIDTH, lbuf);
free(hostname);
}
buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");
if (mvec) {
/*
* Read message from argv[]
*/
int i;
for (i = 0; i < mvecsz; i++) {
buf_puts(bs, mvec[i]);
if (i < mvecsz - 1)
buf_puts(bs, " ");
}
buf_puts(bs, "\r\n");
} else {
/*
* read message from <file>
*/
if (fname) {
/*
* When we are not root, but suid or sgid, refuse to read files
* (e.g. device files) that the user may not have access to.
* After all, our invoker can easily do "wall < file"
* instead of "wall file".
*/
uid_t uid = getuid();
if (uid && (uid != geteuid() || getgid() != getegid()))
errx(EXIT_FAILURE, _("will not read %s - use stdin."),
fname);
if (!freopen(fname, "r", stdin))
err(EXIT_FAILURE, _("cannot open %s"), fname);
}
/*
* Read message from stdin.
*/
while (fgets(lbuf, line_max, stdin)) {
for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
if (cnt == TERM_WIDTH || ch == '\n') {
for (; cnt < TERM_WIDTH; ++cnt)
buf_puts(bs, " ");
buf_puts(bs, "\r\n");
cnt = 0;
}
if (ch == '\t')
cnt += (7 - (cnt % 8));
if (ch != '\n')
buf_putc_careful(bs, ch);
}
}
}
buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");
free(lbuf);
bs->data[bs->used] = '\0'; /* be paranoid */
*mbufsize = bs->used;
return bs->data;
}