[unix-history] / usr / src / usr.bin / write / write.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory.
 *
 * 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.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)write.c	4.22 (Berkeley) 6/1/90";
#endif /* not lint */

#include <sys/param.h>
#include <sys/signal.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <utmp.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>

extern int errno;

main(argc, argv)
	int argc;
	char **argv;
{
	register char *cp;
	time_t atime;
	uid_t myuid;
	int msgsok, myttyfd;
	char tty[MAXPATHLEN], *mytty, *ttyname();
	void done();

	/* check that sender has write enabled */
	if (isatty(fileno(stdin)))
		myttyfd = fileno(stdin);
	else if (isatty(fileno(stdout)))
		myttyfd = fileno(stdout);
	else if (isatty(fileno(stderr)))
		myttyfd = fileno(stderr);
	else {
		(void)fprintf(stderr, "write: can't find your tty\n");
		exit(1);
	}
	if (!(mytty = ttyname(myttyfd))) {
		(void)fprintf(stderr, "write: can't find your tty's name\n");
		exit(1);
	}
	if (cp = rindex(mytty, '/'))
		mytty = cp + 1;
	if (term_chk(mytty, &msgsok, &atime, 1))
		exit(1);
	if (!msgsok) {
		(void)fprintf(stderr,
		    "write: you have write permission turned off.\n");
		exit(1);
	}

	myuid = getuid();

	/* check args */
	switch (argc) {
	case 2:
		search_utmp(argv[1], tty, mytty, myuid);
		do_write(tty, mytty, myuid);
		break;
	case 3:
		if (!strncmp(argv[2], "/dev/", 5))
			argv[2] += 5;
		if (utmp_chk(argv[1], argv[2])) {
			(void)fprintf(stderr,
			    "write: %s is not logged in on %s.\n",
			    argv[1], argv[2]);
			exit(1);
		}
		if (term_chk(argv[2], &msgsok, &atime, 1))
			exit(1);
		if (myuid && !msgsok) {
			(void)fprintf(stderr,
			    "write: %s has messages disabled on %s\n",
			    argv[1], argv[2]);
			exit(1);
		}
		do_write(argv[2], mytty, myuid);
		break;
	default:
		(void)fprintf(stderr, "usage: write user [tty]\n");
		exit(1);
	}
	done();
	/* NOTREACHED */
}

/*
 * utmp_chk - checks that the given user is actually logged in on
 *     the given tty
 */
utmp_chk(user, tty)
	char *user, *tty;
{
	struct utmp u;
	int ufd;

	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
		return(0);	/* ignore error, shouldn't happen anyway */

	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
		if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
		    strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
			(void)close(ufd);
			return(0);
		}

	(void)close(ufd);
	return(1);
}

/*
 * search_utmp - search utmp for the "best" terminal to write to
 *
 * Ignores terminals with messages disabled, and of the rest, returns
 * the one with the most recent access time.  Returns as value the number
 * of the user's terminals with messages enabled, or -1 if the user is
 * not logged in at all.
 *
 * Special case for writing to yourself - ignore the terminal you're
 * writing from, unless that's the only terminal with messages enabled.
 */
search_utmp(user, tty, mytty, myuid)
	char *user, *tty, *mytty;
	uid_t myuid;
{
	struct utmp u;
	time_t bestatime, atime;
	int ufd, nloggedttys, nttys, msgsok, user_is_me;
	char atty[UT_LINESIZE + 1];

	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0) {
		perror("utmp");
		exit(1);
	}

	nloggedttys = nttys = 0;
	bestatime = 0;
	user_is_me = 0;
	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
		if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
			++nloggedttys;
			(void)strncpy(atty, u.ut_line, UT_LINESIZE);
			atty[UT_LINESIZE] = '\0';
			if (term_chk(atty, &msgsok, &atime, 0))
				continue;	/* bad term? skip */
			if (myuid && !msgsok)
				continue;	/* skip ttys with msgs off */
			if (strcmp(atty, mytty) == 0) {
				user_is_me = 1;
				continue;	/* don't write to yourself */
			}
			++nttys;
			if (atime > bestatime) {
				bestatime = atime;
				(void)strcpy(tty, atty);
			}
		}

	(void)close(ufd);
	if (nloggedttys == 0) {
		(void)fprintf(stderr, "write: %s is not logged in\n", user);
		exit(1);
	}
	if (nttys == 0) {
		if (user_is_me) {		/* ok, so write to yourself! */
			(void)strcpy(tty, mytty);
			return;
		}
		(void)fprintf(stderr,
		    "write: %s has messages disabled\n", user);
		exit(1);
	} else if (nttys > 1) {
		(void)fprintf(stderr,
		    "write: %s is logged in more than once; writing to %s\n",
		    user, tty);
	}
}

/*
 * term_chk - check that a terminal exists, and get the message bit
 *     and the access time
 */
term_chk(tty, msgsokP, atimeP, showerror)
	char *tty;
	int *msgsokP, showerror;
	time_t *atimeP;
{
	struct stat s;
	char path[MAXPATHLEN];

	(void)sprintf(path, "/dev/%s", tty);
	if (stat(path, &s) < 0) {
		if (showerror)
			(void)fprintf(stderr,
			    "write: %s: %s\n", path, strerror(errno));
		return(1);
	}
	*msgsokP = (s.st_mode & (S_IWRITE >> 3)) != 0;	/* group write bit */
	*atimeP = s.st_atime;
	return(0);
}

/*
 * do_write - actually make the connection
 */
do_write(tty, mytty, myuid)
	char *tty, *mytty;
	uid_t myuid;
{
	register char *login, *nows;
	register struct passwd *pwd;
	time_t now, time();
	char *getlogin(), path[MAXPATHLEN], host[MAXHOSTNAMELEN], line[512];
	void done();

	/* Determine our login name before the we reopen() stdout */
	if ((login = getlogin()) == NULL)
		if (pwd = getpwuid(myuid))
			login = pwd->pw_name;
		else
			login = "???";

	(void)sprintf(path, "/dev/%s", tty);
	if ((freopen(path, "w", stdout)) == NULL) {
		(void)fprintf(stderr, "write: %s: %s\n", path, strerror(errno));
		exit(1);
	}

	(void)signal(SIGINT, done);
	(void)signal(SIGHUP, done);

	/* print greeting */
	if (gethostname(host, sizeof(host)) < 0)
		(void)strcpy(host, "???");
	now = time((time_t *)NULL);
	nows = ctime(&now);
	nows[16] = '\0';
	(void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n",
	    login, host, mytty, nows + 11);

	while (fgets(line, sizeof(line), stdin) != NULL)
		wr_fputs(line);
}

/*
 * done - cleanup and exit
 */
void
done()
{
	(void)printf("EOF\r\n");
	exit(0);
}

/*
 * wr_fputs - like fputs(), but makes control characters visible and
 *     turns \n into \r\n
 */
wr_fputs(s)
	register char *s;
{
	register char c;

#define	PUTC(c)	if (putchar(c) == EOF) goto err;

	for (; *s != '\0'; ++s) {
		c = toascii(*s);
		if (c == '\n') {
			PUTC('\r');
			PUTC('\n');
		} else if (!isprint(c) && !isspace(c) && c != '\007') {
			PUTC('^');
			PUTC(c^0x40);	/* DEL to ?, others to alpha */
		} else
			PUTC(c);
	}
	return;

err:	(void)fprintf(stderr, "write: %s\n", strerror(errno));
	exit(1);
#undef PUTC
}
Commit	Line	Data
adbc9d44 WJ	1	/*
	2	* Copyright (c) 1989 The Regents of the University of California.
	3	* 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
	38	char copyright[] =
	39	"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
	40	All rights reserved.\n";
	41	#endif /* not lint */
	42
	43	#ifndef lint
	44	static char sccsid[] = "@(#)write.c 4.22 (Berkeley) 6/1/90";
	45	#endif /* not lint */
	46
	47	#include <sys/param.h>
	48	#include <sys/signal.h>
	49	#include <sys/stat.h>
	50	#include <sys/file.h>
	51	#include <sys/time.h>
	52	#include <utmp.h>
	53	#include <ctype.h>
	54	#include <pwd.h>
	55	#include <stdio.h>
	56	#include <string.h>
	57
	58	extern int errno;
	59
	60	main(argc, argv)
	61	int argc;
	62	char **argv;
	63	{
	64	register char *cp;
65	time_t atime;
66	uid_t myuid;
67	int msgsok, myttyfd;
68	char tty[MAXPATHLEN], mytty, ttyname();
69	void done();
70
71	/* check that sender has write enabled */
72	if (isatty(fileno(stdin)))
73	myttyfd = fileno(stdin);
74	else if (isatty(fileno(stdout)))
75	myttyfd = fileno(stdout);
76	else if (isatty(fileno(stderr)))
77	myttyfd = fileno(stderr);
78	else {
79	(void)fprintf(stderr, "write: can't find your tty\n");
80	exit(1);
81	}
82	if (!(mytty = ttyname(myttyfd))) {
83	(void)fprintf(stderr, "write: can't find your tty's name\n");
84	exit(1);
85	}
86	if (cp = rindex(mytty, '/'))
87	mytty = cp + 1;
88	if (term_chk(mytty, &msgsok, &atime, 1))
89	exit(1);
90	if (!msgsok) {
91	(void)fprintf(stderr,
92	"write: you have write permission turned off.\n");
93	exit(1);
94	}
95
96	myuid = getuid();
97
98	/* check args */
99	switch (argc) {
100	case 2:
101	search_utmp(argv[1], tty, mytty, myuid);
102	do_write(tty, mytty, myuid);
103	break;
104	case 3:
105	if (!strncmp(argv[2], "/dev/", 5))
106	argv[2] += 5;
107	if (utmp_chk(argv[1], argv[2])) {
108	(void)fprintf(stderr,
109	"write: %s is not logged in on %s.\n",
110	argv[1], argv[2]);
111	exit(1);
112	}
113	if (term_chk(argv[2], &msgsok, &atime, 1))
114	exit(1);
115	if (myuid && !msgsok) {
116	(void)fprintf(stderr,
117	"write: %s has messages disabled on %s\n",
118	argv[1], argv[2]);
119	exit(1);
120	}
121	do_write(argv[2], mytty, myuid);
122	break;
123	default:
124	(void)fprintf(stderr, "usage: write user [tty]\n");
125	exit(1);
126	}
127	done();
128	/* NOTREACHED */
129	}
130
131	/*
132	* utmp_chk - checks that the given user is actually logged in on
133	* the given tty
134	*/
135	utmp_chk(user, tty)
136	char user, tty;
137	{
138	struct utmp u;
139	int ufd;
140
141	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
142	return(0); /* ignore error, shouldn't happen anyway */
143
144	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
145	if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
146	strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
147	(void)close(ufd);
148	return(0);
149	}
150
151	(void)close(ufd);
152	return(1);
153	}
154
155	/*
156	* search_utmp - search utmp for the "best" terminal to write to
157	*
158	* Ignores terminals with messages disabled, and of the rest, returns
159	* the one with the most recent access time. Returns as value the number
160	* of the user's terminals with messages enabled, or -1 if the user is
161	* not logged in at all.
162	*
163	* Special case for writing to yourself - ignore the terminal you're
164	* writing from, unless that's the only terminal with messages enabled.
165	*/
166	search_utmp(user, tty, mytty, myuid)
167	char user, tty, *mytty;
168	uid_t myuid;
169	{
170	struct utmp u;
171	time_t bestatime, atime;
172	int ufd, nloggedttys, nttys, msgsok, user_is_me;
173	char atty[UT_LINESIZE + 1];
174
175	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0) {
176	perror("utmp");
177	exit(1);
178	}
179
180	nloggedttys = nttys = 0;
181	bestatime = 0;
182	user_is_me = 0;
183	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
184	if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
185	++nloggedttys;
186	(void)strncpy(atty, u.ut_line, UT_LINESIZE);
187	atty[UT_LINESIZE] = '\0';
188	if (term_chk(atty, &msgsok, &atime, 0))
189	continue; /* bad term? skip */
190	if (myuid && !msgsok)
191	continue; /* skip ttys with msgs off */
192	if (strcmp(atty, mytty) == 0) {
193	user_is_me = 1;
194	continue; /* don't write to yourself */
195	}
196	++nttys;
197	if (atime > bestatime) {
198	bestatime = atime;
199	(void)strcpy(tty, atty);
200	}
201	}
202
203	(void)close(ufd);
204	if (nloggedttys == 0) {
205	(void)fprintf(stderr, "write: %s is not logged in\n", user);
206	exit(1);
207	}
208	if (nttys == 0) {
209	if (user_is_me) { /* ok, so write to yourself! */
210	(void)strcpy(tty, mytty);
211	return;
212	}
213	(void)fprintf(stderr,
214	"write: %s has messages disabled\n", user);
215	exit(1);
216	} else if (nttys > 1) {
217	(void)fprintf(stderr,
218	"write: %s is logged in more than once; writing to %s\n",
219	user, tty);
220	}
221	}
222
223	/*
224	* term_chk - check that a terminal exists, and get the message bit
225	* and the access time
226	*/
227	term_chk(tty, msgsokP, atimeP, showerror)
228	char *tty;
229	int *msgsokP, showerror;
230	time_t *atimeP;
231	{
232	struct stat s;
233	char path[MAXPATHLEN];
234
235	(void)sprintf(path, "/dev/%s", tty);
236	if (stat(path, &s) < 0) {
237	if (showerror)
238	(void)fprintf(stderr,
239	"write: %s: %s\n", path, strerror(errno));
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	*/
250	do_write(tty, mytty, myuid)
251	char tty, mytty;
252	uid_t myuid;
253	{
254	register char login, nows;
255	register struct passwd *pwd;
256	time_t now, time();
257	char *getlogin(), path[MAXPATHLEN], host[MAXHOSTNAMELEN], line[512];
258	void done();
259
260	/* Determine our login name before the we reopen() stdout */
261	if ((login = getlogin()) == NULL)
262	if (pwd = getpwuid(myuid))
263	login = pwd->pw_name;
264	else
265	login = "???";
266
267	(void)sprintf(path, "/dev/%s", tty);
268	if ((freopen(path, "w", stdout)) == NULL) {
269	(void)fprintf(stderr, "write: %s: %s\n", path, strerror(errno));
270	exit(1);
271	}
272
273	(void)signal(SIGINT, done);
274	(void)signal(SIGHUP, done);
275
276	/* print greeting */
277	if (gethostname(host, sizeof(host)) < 0)
278	(void)strcpy(host, "???");
279	now = time((time_t *)NULL);
280	nows = ctime(&now);
281	nows[16] = '\0';
282	(void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n",
283	login, host, mytty, nows + 11);
284
285	while (fgets(line, sizeof(line), stdin) != NULL)
286	wr_fputs(line);
287	}
288
289	/*
290	* done - cleanup and exit
291	*/
292	void
293	done()
294	{
295	(void)printf("EOF\r\n");
296	exit(0);
297	}
298
299	/*
300	* wr_fputs - like fputs(), but makes control characters visible and
301	* turns \n into \r\n
302	*/
303	wr_fputs(s)
304	register char *s;
305	{
306	register char c;
307
308	#define PUTC(c) if (putchar(c) == EOF) goto err;
309
310	for (; *s != '\0'; ++s) {
311	c = toascii(*s);
312	if (c == '\n') {
313	PUTC('\r');
314	PUTC('\n');
315	} else if (!isprint(c) && !isspace(c) && c != '\007') {
316	PUTC('^');
317	PUTC(c^0x40); /* DEL to ?, others to alpha */
318	} else
319	PUTC(c);
320	}
321	return;
322
323	err: (void)fprintf(stderr, "write: %s\n", strerror(errno));
324	exit(1);
325	#undef PUTC
326	}