usr.bin/wall/wall.c

   1 /*      $NetBSD: wall.c,v 1.29 2011/09/06 18:45:21 joerg Exp $  */
   2
   3 /*
   4  * Copyright (c) 1988, 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __COPYRIGHT("@(#) Copyright (c) 1988, 1990, 1993\
  35  The Regents of the University of California.  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)wall.c      8.2 (Berkeley) 11/16/93";
  41 #endif
  42 __RCSID("$NetBSD: wall.c,v 1.29 2011/09/06 18:45:21 joerg Exp $");
  43 #endif /* not lint */
  44
  45 /*
  46  * This program is not related to David Wall, whose Stanford Ph.D. thesis
  47  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
  48  */
  49
  50 #include <sys/param.h>
  51 #include <sys/stat.h>
  52 #include <sys/time.h>
  53 #include <sys/uio.h>
  54
  55 #include <ctype.h>
  56 #include <err.h>
  57 #include <grp.h>
  58 #include <errno.h>
  59 #include <paths.h>
  60 #include <pwd.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64 #include <unistd.h>
  65 #include <util.h>
  66
  67 #include "utmpentry.h"
  68 #include "term_chk.h"
  69
  70 static void     addgroup(char *);
  71 static void     makemsg(const char *);
  72 __dead static void      usage(void);
  73
  74 static struct wallgroup {
  75         gid_t   gid;
  76         char    *name;
  77         char    **mem;
  78         struct wallgroup *next;
  79 } *grouplist;
  80
  81 static int nobanner;
  82 static size_t mbufsize;
  83 static char *mbuf;
  84
  85 /* ARGSUSED */
  86 int
  87 main(int argc, char **argv)
  88 {
  89         int ch;
  90         struct iovec iov;
  91         char *p, **mem;
  92         struct utmpentry *ep;
  93         gid_t egid;
  94         struct wallgroup *wg;
  95         struct passwd *pw;
  96
  97         setprogname(argv[0]);
  98         egid = getegid();
  99         if (setegid(getgid()) == -1)
 100                 err(1, "setegid");
 101         pw = getpwnam("nobody");
 102
 103         (void)check_sender(NULL, getuid(), egid);
 104
 105         while ((ch = getopt(argc, argv, "g:n")) != -1)
 106                 switch (ch) {
 107                 case 'n':
 108                         /* undoc option for shutdown: suppress banner */
 109                         if (geteuid() == 0 || (pw && getuid() == pw->pw_uid))
 110                                 nobanner = 1;
 111                         break;
 112                 case 'g':
 113                         addgroup(optarg);
 114                         break;
 115                 case '?':
 116                 default:
 117                         usage();
 118                 }
 119         argc -= optind;
 120         argv += optind;
 121         if (argc > 1)
 122                 usage();
 123
 124         makemsg(*argv);
 125
 126         iov.iov_base = mbuf;
 127         iov.iov_len = mbufsize;
 128         (void)getutentries(NULL, &ep);
 129         (void)setegid(egid);
 130         for (; ep; ep = ep->next) {
 131                 if (grouplist) {
 132                         int ingroup;
 133
 134                         ingroup = 0;
 135                         pw = getpwnam(ep->name);
 136                         if (!pw)
 137                                 continue;
 138                         for (wg = grouplist; wg && !ingroup; wg = wg->next) {
 139                                 if (wg->gid == pw->pw_gid)
 140                                         ingroup = 1;
 141                                 for (mem = wg->mem; *mem && !ingroup; mem++)
 142                                         if (strcmp(ep->name, *mem) == 0)
 143                                                 ingroup = 1;
 144                         }
 145                         if (ingroup == 0)
 146                                 continue;
 147                 }
 148
 149                 /* skip [xgk]dm/xserver entries (":0", ":1", etc.) */
 150                 if (ep->line[0] == ':' && isdigit((unsigned char)ep->line[1]))
 151                         continue;
 152
 153                 if ((p = ttymsg(&iov, 1, ep->line, 60*5)) != NULL)
 154                         warnx("%s", p);
 155         }
 156         exit(0);
 157 }
 158
 159 static void
 160 addgroup(char *name)
 161 {
 162         int i;
 163         struct group *grp;
 164         struct wallgroup *g;
 165
 166         grp = getgrnam(name);
 167         if ((grp = getgrnam(name)) == NULL)
 168                 errx(1, "unknown group `%s'", name);
 169         for (i = 0; grp->gr_mem[i]; i++)
 170                 continue;
 171
 172         g = (struct wallgroup *)malloc(sizeof *g);
 173         if (g == NULL)
 174                 err(1, "malloc");
 175         g->gid = grp->gr_gid;
 176         g->name = name;
 177         g->mem = (char **)malloc(i + 1);
 178         if (g->mem == NULL)
 179                 err(1, "malloc");
 180         for (i = 0; grp->gr_mem[i] != NULL; i++) {
 181                 g->mem[i] = strdup(grp->gr_mem[i]);
 182                 if (g->mem[i] == NULL)
 183                         err(1, "malloc");
 184         }
 185         g->mem[i] = NULL;
 186         g->next = grouplist;
 187         grouplist = g;
 188 }
 189
 190 static void
 191 makemsg(const char *fname)
 192 {
 193         int ch, cnt;
 194         struct tm *lt;
 195         struct passwd *pw;
 196         struct stat sbuf;
 197         time_t now;
 198         FILE *fp;
 199         int fd;
 200         const char *whom, *tty;
 201         char *p, tmpname[MAXPATHLEN], lbuf[100],
 202             hostname[MAXHOSTNAMELEN+1];
 203
 204         (void)snprintf(tmpname, sizeof tmpname, "%s/wall.XXXXXX", _PATH_TMP);
 205         if ((fd = mkstemp(tmpname)) == -1)
 206                 err(1, "can't open temporary file");
 207         (void)unlink(tmpname);
 208         if (!(fp = fdopen(fd, "r+")))
 209                 err(1, "can't open temporary file");
 210
 211         if (!nobanner) {
 212                 if (!(whom = getlogin()))
 213                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 214                 (void)gethostname(hostname, sizeof(hostname));
 215                 hostname[sizeof(hostname) - 1] = '\0';
 216                 (void)time(&now);
 217                 lt = localtime(&now);
 218
 219                 /*
 220                  * all this stuff is to blank out a square for the message;
 221                  * we wrap message lines at column 79, not 80, because some
 222                  * terminals wrap after 79, some do not, and we can't tell.
 223                  * Which means that we may leave a non-blank character
 224                  * in column 80, but that can't be helped.
 225                  */
 226                 (void)fprintf(fp, "\r%79s\r\n", " ");
 227                 (void)snprintf(lbuf, sizeof lbuf,
 228                     "Broadcast Message from %s@%s", whom, hostname);
 229                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 230                 tty = ttyname(STDERR_FILENO);
 231                 if (tty == NULL)
 232                         tty = "??";
 233                 (void)snprintf(lbuf, sizeof lbuf,
 234                     "        (%s) at %d:%02d %s...", tty,
 235                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 236                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 237         }
 238         (void)fprintf(fp, "%79s\r\n", " ");
 239
 240         if (fname && !(freopen(fname, "r", stdin)))
 241                 err(1, "can't read %s", fname);
 242         while (fgets(lbuf, sizeof(lbuf), stdin))
 243                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 244                         if (cnt == 79 || ch == '\n') {
 245                                 for (; cnt < 79; ++cnt)
 246                                         putc(' ', fp);
 247                                 putc('\r', fp);
 248                                 putc('\n', fp);
 249                                 cnt = -1;
 250                         }
 251                         if (ch != '\n')
 252                                 putc(ch, fp);
 253                 }
 254         (void)fprintf(fp, "%79s\r\n", " ");
 255         rewind(fp);
 256
 257         if (fstat(fd, &sbuf))
 258                 err(1, "can't stat temporary file");
 259         if ((uint64_t)sbuf.st_size > SIZE_T_MAX)
 260                 errx(1, "file too big");
 261         mbufsize = sbuf.st_size;
 262         if (!(mbuf = malloc(mbufsize)))
 263                 err(1, "malloc");
 264         if (fread(mbuf, 1, mbufsize, fp) != mbufsize)
 265                 err(1, "can't read temporary file");
 266         (void)fclose(fp);
 267 }
 268
 269 static void
 270 usage(void)
 271 {
 272
 273         (void)fprintf(stderr, "usage: %s [-g group] [file]\n", getprogname());
 274         exit(1);
 275 }