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Annotation of src/usr.bin/wall/wall.c, Revision 1.31

1.31    ! schwarze    1: /*     $OpenBSD: wall.c,v 1.30 2016/05/08 16:19:35 martijn Exp $       */
1.1       deraadt     2: /*     $NetBSD: wall.c,v 1.6 1994/11/17 07:17:58 jtc Exp $     */
                      3:
                      4: /*
                      5:  * Copyright (c) 1988, 1990, 1993
                      6:  *     The Regents of the University of California.  All rights reserved.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
1.18      millert    16:  * 3. Neither the name of the University nor the names of its contributors
1.1       deraadt    17:  *    may be used to endorse or promote products derived from this software
                     18:  *    without specific prior written permission.
                     19:  *
                     20:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     21:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     22:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     23:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     24:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     25:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     26:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     27:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     28:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     29:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     30:  * SUCH DAMAGE.
                     31:  */
                     32:
                     33: /*
                     34:  * This program is not related to David Wall, whose Stanford Ph.D. thesis
                     35:  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
                     36:  */
                     37:
1.29      benno      38: #include <sys/queue.h>
1.1       deraadt    39: #include <sys/stat.h>
                     40: #include <sys/time.h>
                     41: #include <sys/uio.h>
                     42:
1.30      martijn    43: #include <ctype.h>
                     44: #include <err.h>
                     45: #include <grp.h>
                     46: #include <limits.h>
1.1       deraadt    47: #include <paths.h>
                     48: #include <pwd.h>
                     49: #include <stdio.h>
                     50: #include <stdlib.h>
                     51: #include <string.h>
                     52: #include <unistd.h>
                     53: #include <utmp.h>
                     54:
1.6       deraadt    55: struct wallgroup {
1.15      millert    56:        gid_t   gid;
                     57:        char    *name;
                     58:        char    **mem;
1.6       deraadt    59:        struct wallgroup *next;
                     60: } *grouplist;
                     61:
1.29      benno      62: struct utmptty {
                     63:        char    *tty;
                     64:        SLIST_ENTRY(utmptty) next;
                     65: };
                     66:
1.15      millert    67: void   makemsg(char *);
                     68: void   addgroup(struct group *, char *);
                     69: char   *ttymsg(struct iovec *, int, char *, int);
                     70: __dead void usage(void);
1.30      martijn    71: static int isu8cont(unsigned char);
1.1       deraadt    72:
                     73: int nobanner;
                     74: int mbufsize;
                     75: char *mbuf;
                     76:
                     77: /* ARGSUSED */
                     78: int
1.15      millert    79: main(int argc, char **argv)
1.1       deraadt    80: {
1.15      millert    81:        FILE *fp;
                     82:        int ch, ingroup;
1.1       deraadt    83:        struct iovec iov;
                     84:        struct utmp utmp;
1.15      millert    85:        char *p, **mem;
1.1       deraadt    86:        char line[sizeof(utmp.ut_line) + 1];
1.15      millert    87:        char username[sizeof(utmp.ut_name) + 1];
                     88:        struct passwd *pw;
                     89:        struct group *grp;
1.6       deraadt    90:        struct wallgroup *g;
1.29      benno      91:        struct utmptty *un;
                     92:        SLIST_HEAD(,utmptty) utmphead;
                     93:        SLIST_INIT(&utmphead);
1.1       deraadt    94:
1.8       millert    95:        while ((ch = getopt(argc, argv, "ng:")) != -1)
1.1       deraadt    96:                switch (ch) {
                     97:                case 'n':
                     98:                        /* undoc option for shutdown: suppress banner */
1.15      millert    99:                        pw = getpwnam("nobody");
                    100:                        if (geteuid() == 0 || (pw && getuid() == pw->pw_uid))
1.1       deraadt   101:                                nobanner = 1;
                    102:                        break;
1.6       deraadt   103:                case 'g':
1.15      millert   104:                        if ((grp = getgrnam(optarg)) == NULL)
                    105:                                errx(1, "unknown group `%s'", optarg);
                    106:                        addgroup(grp, optarg);
1.6       deraadt   107:                        break;
1.1       deraadt   108:                default:
1.15      millert   109:                        usage();
1.1       deraadt   110:                }
                    111:        argc -= optind;
                    112:        argv += optind;
                    113:        if (argc > 1)
1.15      millert   114:                usage();
1.6       deraadt   115:
1.1       deraadt   116:        makemsg(*argv);
                    117:
1.29      benno     118:        if (pledge("stdio rpath wpath getpw proc", NULL) == -1)
                    119:                err(1, "pledge");
                    120:
1.9       form      121:        if (!(fp = fopen(_PATH_UTMP, "r")))
1.21      henning   122:                err(1, "cannot read %s", _PATH_UTMP);
1.1       deraadt   123:        iov.iov_base = mbuf;
                    124:        iov.iov_len = mbufsize;
1.29      benno     125:
1.15      millert   126:        while (fread(&utmp, sizeof(utmp), 1, fp) == 1) {
1.16      deraadt   127:                if (!utmp.ut_name[0])
1.1       deraadt   128:                        continue;
1.6       deraadt   129:                if (grouplist) {
1.15      millert   130:                        ingroup = 0;
                    131:                        strncpy(username, utmp.ut_name, sizeof(utmp.ut_name));
                    132:                        username[sizeof(utmp.ut_name)] = '\0';
1.6       deraadt   133:                        pw = getpwnam(username);
                    134:                        if (!pw)
                    135:                                continue;
                    136:                        for (g = grouplist; g && ingroup == 0; g = g->next) {
                    137:                                if (g->gid == pw->pw_gid)
                    138:                                        ingroup = 1;
1.15      millert   139:                                for (mem = g->mem; *mem && ingroup == 0; mem++)
                    140:                                        if (strcmp(username, *mem) == 0)
1.6       deraadt   141:                                                ingroup = 1;
                    142:                        }
                    143:                        if (ingroup == 0)
                    144:                                continue;
                    145:                }
1.1       deraadt   146:                strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
                    147:                line[sizeof(utmp.ut_line)] = '\0';
1.29      benno     148:                un = malloc(sizeof(struct utmptty));
                    149:                if (un == NULL)
                    150:                        err(1, "malloc");
                    151:                un->tty = strndup(line, sizeof(utmp.ut_line));
                    152:                if (un->tty == NULL)
                    153:                        err(1, "strndup");
                    154:                SLIST_INSERT_HEAD(&utmphead, un, next);
                    155:        }
                    156:        fclose(fp);
                    157:
                    158:        if (pledge("stdio rpath wpath proc", NULL) == -1)
                    159:                err(1, "pledge");
                    160:
                    161:        SLIST_FOREACH(un, &utmphead, next) {
                    162:                if ((p = ttymsg(&iov, 1, un->tty, 60*5)) != NULL)
1.13      deraadt   163:                        warnx("%s", p);
1.1       deraadt   164:        }
1.29      benno     165:
1.1       deraadt   166:        exit(0);
                    167: }
                    168:
                    169: void
1.15      millert   170: makemsg(char *fname)
1.1       deraadt   171: {
1.30      martijn   172:        int cnt;
1.1       deraadt   173:        struct tm *lt;
                    174:        struct passwd *pw;
                    175:        struct stat sbuf;
1.19      deraadt   176:        time_t now;
1.1       deraadt   177:        FILE *fp;
                    178:        int fd;
1.26      deraadt   179:        char *p, *whom, hostname[HOST_NAME_MAX+1], lbuf[100], tmpname[PATH_MAX];
1.11      d         180:        char *ttynam;
1.30      martijn   181:        unsigned char ch;
1.1       deraadt   182:
1.20      avsm      183:        snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXXXXXX", _PATH_TMP);
1.15      millert   184:        if ((fd = mkstemp(tmpname)) >= 0) {
                    185:                (void)unlink(tmpname);
                    186:                fp = fdopen(fd, "r+");
                    187:        }
                    188:        if (fd == -1 || fp == NULL)
1.21      henning   189:                err(1, "can't open temporary file");
1.1       deraadt   190:
                    191:        if (!nobanner) {
                    192:                if (!(whom = getlogin()))
                    193:                        whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
                    194:                (void)gethostname(hostname, sizeof(hostname));
                    195:                (void)time(&now);
                    196:                lt = localtime(&now);
1.11      d         197:                if ((ttynam = ttyname(STDERR_FILENO)) == NULL)
                    198:                        ttynam = "(not a tty)";
1.1       deraadt   199:
                    200:                /*
                    201:                 * all this stuff is to blank out a square for the message;
                    202:                 * we wrap message lines at column 79, not 80, because some
                    203:                 * terminals wrap after 79, some do not, and we can't tell.
                    204:                 * Which means that we may leave a non-blank character
                    205:                 * in column 80, but that can't be helped.
                    206:                 */
                    207:                (void)fprintf(fp, "\r%79s\r\n", " ");
1.3       deraadt   208:                (void)snprintf(lbuf, sizeof lbuf,
                    209:                    "Broadcast Message from %s@%s", whom, hostname);
1.1       deraadt   210:                (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
1.3       deraadt   211:                (void)snprintf(lbuf, sizeof lbuf,
1.11      d         212:                    "        (%s) at %d:%02d ...", ttynam,
1.1       deraadt   213:                    lt->tm_hour, lt->tm_min);
                    214:                (void)fprintf(fp, "%-79.79s\r\n", lbuf);
                    215:        }
                    216:        (void)fprintf(fp, "%79s\r\n", " ");
                    217:
1.13      deraadt   218:        if (fname) {
                    219:                gid_t egid = getegid();
                    220:
                    221:                setegid(getgid());
                    222:                if (freopen(fname, "r", stdin) == NULL)
1.21      henning   223:                        err(1, "can't read %s", fname);
1.13      deraadt   224:                setegid(egid);
                    225:        }
1.1       deraadt   226:        while (fgets(lbuf, sizeof(lbuf), stdin))
                    227:                for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
1.30      martijn   228:                        if (cnt == 79 || ch == '\n') {
                    229:                                for (; cnt < 79; ++cnt)
1.1       deraadt   230:                                        putc(' ', fp);
                    231:                                putc('\r', fp);
                    232:                                putc('\n', fp);
                    233:                                cnt = -1;
1.30      martijn   234:                        } else if (!isu8cont(ch))
                    235:                                putc(isprint(ch) || isspace(ch) ?
                    236:                                    ch : '?', fp);
1.1       deraadt   237:                }
                    238:        (void)fprintf(fp, "%79s\r\n", " ");
                    239:        rewind(fp);
                    240:
1.9       form      241:        if (fstat(fd, &sbuf))
1.21      henning   242:                err(1, "can't stat temporary file");
1.1       deraadt   243:        mbufsize = sbuf.st_size;
1.22      tom       244:        mbuf = malloc((u_int)mbufsize);
                    245:        if (mbuf == NULL)
                    246:                err(1, NULL);
1.9       form      247:        if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
1.21      henning   248:                err(1, "can't read temporary file");
1.1       deraadt   249:        (void)close(fd);
1.15      millert   250: }
                    251:
                    252: void
                    253: addgroup(struct group *grp, char *name)
                    254: {
                    255:        int i;
                    256:        struct wallgroup *g;
                    257:
                    258:        for (i = 0; grp->gr_mem[i]; i++)
                    259:                ;
                    260:
1.27      deraadt   261:        g = malloc(sizeof *g);
1.15      millert   262:        if (g == NULL)
1.22      tom       263:                err(1, NULL);
1.15      millert   264:        g->gid = grp->gr_gid;
                    265:        g->name = name;
1.27      deraadt   266:        g->mem = calloc(i + 1, sizeof(char *));
1.15      millert   267:        if (g->mem == NULL)
1.22      tom       268:                err(1, NULL);
1.15      millert   269:        for (i = 0; grp->gr_mem[i] != NULL; i++) {
                    270:                g->mem[i] = strdup(grp->gr_mem[i]);
                    271:                if (g->mem[i] == NULL)
1.22      tom       272:                        err(1, NULL);
1.15      millert   273:        }
                    274:        g->mem[i] = NULL;
                    275:        g->next = grouplist;
                    276:        grouplist = g;
                    277: }
                    278:
                    279: void
                    280: usage(void)
                    281: {
                    282:        extern char *__progname;
                    283:
                    284:        (void)fprintf(stderr, "usage: %s [-g group] [file]\n", __progname);
                    285:        exit(1);
1.30      martijn   286: }
                    287:
                    288: static int
                    289: isu8cont(unsigned char c)
                    290: {
                    291:        return (c & (0x80 | 0x40)) == 0x80;
1.1       deraadt   292: }