1/*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory.
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.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1989, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
41#endif
42
43#if 0
44#ifndef lint
45static char sccsid[] = "@(#)write.c 8.1 (Berkeley) 6/6/93";
46#endif
47#endif
48
49#include <sys/cdefs.h>
| 1/*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory.
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.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1989, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
41#endif
42
43#if 0
44#ifndef lint
45static char sccsid[] = "@(#)write.c 8.1 (Berkeley) 6/6/93";
46#endif
47#endif
48
49#include <sys/cdefs.h>
|
105 if (term_chk(mytty, &msgsok, &atime, 1))
106 exit(1);
107 if (!msgsok)
108 errx(1, "you have write permission turned off");
109
110 myuid = getuid();
111
112 /* check args */
113 switch (argc) {
114 case 1:
115 search_utmp(argv[0], tty, mytty, myuid);
116 do_write(tty, mytty, myuid);
117 break;
118 case 2:
119 if (!strncmp(argv[1], _PATH_DEV, strlen(_PATH_DEV)))
120 argv[1] += strlen(_PATH_DEV);
121 if (utmp_chk(argv[0], argv[1]))
122 errx(1, "%s is not logged in on %s", argv[0], argv[1]);
123 if (term_chk(argv[1], &msgsok, &atime, 1))
124 exit(1);
125 if (myuid && !msgsok)
126 errx(1, "%s has messages disabled on %s", argv[0], argv[1]);
127 do_write(argv[1], mytty, myuid);
128 break;
129 default:
130 usage();
131 }
132 done(0);
133 return (0);
134}
135
136static void
137usage(void)
138{
139 (void)fprintf(stderr, "usage: write user [tty]\n");
140 exit(1);
141}
142
143/*
144 * utmp_chk - checks that the given user is actually logged in on
145 * the given tty
146 */
147int
148utmp_chk(char *user, char *tty)
149{
150 struct utmp u;
151 int ufd;
152
153 if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
154 return(0); /* ignore error, shouldn't happen anyway */
155
156 while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
157 if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
158 strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
159 (void)close(ufd);
160 return(0);
161 }
162
163 (void)close(ufd);
164 return(1);
165}
166
167/*
168 * search_utmp - search utmp for the "best" terminal to write to
169 *
170 * Ignores terminals with messages disabled, and of the rest, returns
171 * the one with the most recent access time. Returns as value the number
172 * of the user's terminals with messages enabled, or -1 if the user is
173 * not logged in at all.
174 *
175 * Special case for writing to yourself - ignore the terminal you're
176 * writing from, unless that's the only terminal with messages enabled.
177 */
178void
179search_utmp(char *user, char *tty, char *mytty, uid_t myuid)
180{
181 struct utmp u;
182 time_t bestatime, atime;
183 int ufd, nloggedttys, nttys, msgsok, user_is_me;
184 char atty[UT_LINESIZE + 1];
185
186 if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
187 err(1, "utmp");
188
189 nloggedttys = nttys = 0;
190 bestatime = 0;
191 user_is_me = 0;
192 while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
193 if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
194 ++nloggedttys;
195 (void)strncpy(atty, u.ut_line, UT_LINESIZE);
196 atty[UT_LINESIZE] = '\0';
197 if (term_chk(atty, &msgsok, &atime, 0))
198 continue; /* bad term? skip */
199 if (myuid && !msgsok)
200 continue; /* skip ttys with msgs off */
201 if (strcmp(atty, mytty) == 0) {
202 user_is_me = 1;
203 continue; /* don't write to yourself */
204 }
205 ++nttys;
206 if (atime > bestatime) {
207 bestatime = atime;
208 (void)strcpy(tty, atty);
209 }
210 }
211
212 (void)close(ufd);
213 if (nloggedttys == 0)
214 errx(1, "%s is not logged in", user);
215 if (nttys == 0) {
216 if (user_is_me) { /* ok, so write to yourself! */
217 (void)strcpy(tty, mytty);
218 return;
219 }
220 errx(1, "%s has messages disabled", user);
221 } else if (nttys > 1) {
222 warnx("%s is logged in more than once; writing to %s", user, tty);
223 }
224}
225
226/*
227 * term_chk - check that a terminal exists, and get the message bit
228 * and the access time
229 */
230int
231term_chk(char *tty, int *msgsokP, time_t *atimeP, int showerror)
232{
233 struct stat s;
234 char path[MAXPATHLEN];
235
236 (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
237 if (stat(path, &s) < 0) {
238 if (showerror)
239 warn("%s", path);
240 return(1);
241 }
242 *msgsokP = (s.st_mode & (S_IWRITE >> 3)) != 0; /* group write bit */
243 *atimeP = s.st_atime;
244 return(0);
245}
246
247/*
248 * do_write - actually make the connection
249 */
250void
251do_write(char *tty, char *mytty, uid_t myuid)
252{
253 const char *login;
254 char *nows;
255 struct passwd *pwd;
256 time_t now;
257 char path[MAXPATHLEN], host[MAXHOSTNAMELEN], line[512];
258
259 /* Determine our login name before we reopen() stdout */
260 if ((login = getlogin()) == NULL) {
261 if ((pwd = getpwuid(myuid)))
262 login = pwd->pw_name;
263 else
264 login = "???";
265 }
266
267 (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
268 if ((freopen(path, "w", stdout)) == NULL)
269 err(1, "%s", path);
270
271 (void)signal(SIGINT, done);
272 (void)signal(SIGHUP, done);
273
274 /* print greeting */
275 if (gethostname(host, sizeof(host)) < 0)
276 (void)strcpy(host, "???");
277 now = time((time_t *)NULL);
278 nows = ctime(&now);
279 nows[16] = '\0';
280 (void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n",
281 login, host, mytty, nows + 11);
282
283 while (fgets(line, sizeof(line), stdin) != NULL)
284 wr_fputs(line);
285}
286
287/*
288 * done - cleanup and exit
289 */
290void
291done(int n __unused)
292{
293 (void)printf("EOF\r\n");
294 exit(0);
295}
296
297/*
298 * wr_fputs - like fputs(), but makes control characters visible and
299 * turns \n into \r\n
300 */
301void
302wr_fputs(unsigned char *s)
303{
304
305#define PUTC(c) if (putchar(c) == EOF) err(1, NULL);
306
307 for (; *s != '\0'; ++s) {
308 if (*s == '\n') {
309 PUTC('\r');
310 } else if (((*s & 0x80) && *s < 0xA0) ||
311 /* disable upper controls */
312 (!isprint(*s) && !isspace(*s) &&
313 *s != '\a' && *s != '\b')
314 ) {
315 if (*s & 0x80) {
316 *s &= ~0x80;
317 PUTC('M');
318 PUTC('-');
319 }
320 if (iscntrl(*s)) {
321 *s ^= 0x40;
322 PUTC('^');
323 }
324 }
325 PUTC(*s);
326 }
327 return;
328#undef PUTC
329}
| 104 if (term_chk(mytty, &msgsok, &atime, 1))
105 exit(1);
106 if (!msgsok)
107 errx(1, "you have write permission turned off");
108
109 myuid = getuid();
110
111 /* check args */
112 switch (argc) {
113 case 1:
114 search_utmp(argv[0], tty, mytty, myuid);
115 do_write(tty, mytty, myuid);
116 break;
117 case 2:
118 if (!strncmp(argv[1], _PATH_DEV, strlen(_PATH_DEV)))
119 argv[1] += strlen(_PATH_DEV);
120 if (utmp_chk(argv[0], argv[1]))
121 errx(1, "%s is not logged in on %s", argv[0], argv[1]);
122 if (term_chk(argv[1], &msgsok, &atime, 1))
123 exit(1);
124 if (myuid && !msgsok)
125 errx(1, "%s has messages disabled on %s", argv[0], argv[1]);
126 do_write(argv[1], mytty, myuid);
127 break;
128 default:
129 usage();
130 }
131 done(0);
132 return (0);
133}
134
135static void
136usage(void)
137{
138 (void)fprintf(stderr, "usage: write user [tty]\n");
139 exit(1);
140}
141
142/*
143 * utmp_chk - checks that the given user is actually logged in on
144 * the given tty
145 */
146int
147utmp_chk(char *user, char *tty)
148{
149 struct utmp u;
150 int ufd;
151
152 if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
153 return(0); /* ignore error, shouldn't happen anyway */
154
155 while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
156 if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
157 strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
158 (void)close(ufd);
159 return(0);
160 }
161
162 (void)close(ufd);
163 return(1);
164}
165
166/*
167 * search_utmp - search utmp for the "best" terminal to write to
168 *
169 * Ignores terminals with messages disabled, and of the rest, returns
170 * the one with the most recent access time. Returns as value the number
171 * of the user's terminals with messages enabled, or -1 if the user is
172 * not logged in at all.
173 *
174 * Special case for writing to yourself - ignore the terminal you're
175 * writing from, unless that's the only terminal with messages enabled.
176 */
177void
178search_utmp(char *user, char *tty, char *mytty, uid_t myuid)
179{
180 struct utmp u;
181 time_t bestatime, atime;
182 int ufd, nloggedttys, nttys, msgsok, user_is_me;
183 char atty[UT_LINESIZE + 1];
184
185 if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
186 err(1, "utmp");
187
188 nloggedttys = nttys = 0;
189 bestatime = 0;
190 user_is_me = 0;
191 while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
192 if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
193 ++nloggedttys;
194 (void)strncpy(atty, u.ut_line, UT_LINESIZE);
195 atty[UT_LINESIZE] = '\0';
196 if (term_chk(atty, &msgsok, &atime, 0))
197 continue; /* bad term? skip */
198 if (myuid && !msgsok)
199 continue; /* skip ttys with msgs off */
200 if (strcmp(atty, mytty) == 0) {
201 user_is_me = 1;
202 continue; /* don't write to yourself */
203 }
204 ++nttys;
205 if (atime > bestatime) {
206 bestatime = atime;
207 (void)strcpy(tty, atty);
208 }
209 }
210
211 (void)close(ufd);
212 if (nloggedttys == 0)
213 errx(1, "%s is not logged in", user);
214 if (nttys == 0) {
215 if (user_is_me) { /* ok, so write to yourself! */
216 (void)strcpy(tty, mytty);
217 return;
218 }
219 errx(1, "%s has messages disabled", user);
220 } else if (nttys > 1) {
221 warnx("%s is logged in more than once; writing to %s", user, tty);
222 }
223}
224
225/*
226 * term_chk - check that a terminal exists, and get the message bit
227 * and the access time
228 */
229int
230term_chk(char *tty, int *msgsokP, time_t *atimeP, int showerror)
231{
232 struct stat s;
233 char path[MAXPATHLEN];
234
235 (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
236 if (stat(path, &s) < 0) {
237 if (showerror)
238 warn("%s", path);
239 return(1);
240 }
241 *msgsokP = (s.st_mode & (S_IWRITE >> 3)) != 0; /* group write bit */
242 *atimeP = s.st_atime;
243 return(0);
244}
245
246/*
247 * do_write - actually make the connection
248 */
249void
250do_write(char *tty, char *mytty, uid_t myuid)
251{
252 const char *login;
253 char *nows;
254 struct passwd *pwd;
255 time_t now;
256 char path[MAXPATHLEN], host[MAXHOSTNAMELEN], line[512];
257
258 /* Determine our login name before we reopen() stdout */
259 if ((login = getlogin()) == NULL) {
260 if ((pwd = getpwuid(myuid)))
261 login = pwd->pw_name;
262 else
263 login = "???";
264 }
265
266 (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
267 if ((freopen(path, "w", stdout)) == NULL)
268 err(1, "%s", path);
269
270 (void)signal(SIGINT, done);
271 (void)signal(SIGHUP, done);
272
273 /* print greeting */
274 if (gethostname(host, sizeof(host)) < 0)
275 (void)strcpy(host, "???");
276 now = time((time_t *)NULL);
277 nows = ctime(&now);
278 nows[16] = '\0';
279 (void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n",
280 login, host, mytty, nows + 11);
281
282 while (fgets(line, sizeof(line), stdin) != NULL)
283 wr_fputs(line);
284}
285
286/*
287 * done - cleanup and exit
288 */
289void
290done(int n __unused)
291{
292 (void)printf("EOF\r\n");
293 exit(0);
294}
295
296/*
297 * wr_fputs - like fputs(), but makes control characters visible and
298 * turns \n into \r\n
299 */
300void
301wr_fputs(unsigned char *s)
302{
303
304#define PUTC(c) if (putchar(c) == EOF) err(1, NULL);
305
306 for (; *s != '\0'; ++s) {
307 if (*s == '\n') {
308 PUTC('\r');
309 } else if (((*s & 0x80) && *s < 0xA0) ||
310 /* disable upper controls */
311 (!isprint(*s) && !isspace(*s) &&
312 *s != '\a' && *s != '\b')
313 ) {
314 if (*s & 0x80) {
315 *s &= ~0x80;
316 PUTC('M');
317 PUTC('-');
318 }
319 if (iscntrl(*s)) {
320 *s ^= 0x40;
321 PUTC('^');
322 }
323 }
324 PUTC(*s);
325 }
326 return;
327#undef PUTC
328}
|