Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/write/write.c	Lines:	0	124	0.0 %
Date:	2016-12-06	Branches:	0	123	0.0 %


/*	$OpenBSD: write.c,v 1.33 2016/02/05 19:00:39 martijn Exp $	*/
/*	$NetBSD: write.c,v 1.5 1995/08/31 21:48:32 jtc Exp $	*/

/*
 * Copyright (c) 1989, 1993
 *	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. 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.
 */

#include <sys/stat.h>

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>

void done(int sig);
void do_write(char *, char *, uid_t);
void wr_fputs(char *);
void search_utmp(char *, char *, int, char *, uid_t);
int term_chk(char *, int *, time_t *, int);
int utmp_chk(char *, char *);
static int isu8cont(unsigned char c);

int
main(int argc, char *argv[])
{
	char tty[PATH_MAX], *mytty, *cp;
	int msgsok, myttyfd;
	time_t atime;
	uid_t myuid;

	/* 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
		errx(1, "can't find your tty");
	if (!(mytty = ttyname(myttyfd)))
		errx(1, "can't find your tty's name");
	if ((cp = strrchr(mytty, '/')))
		mytty = cp + 1;
	if (term_chk(mytty, &msgsok, &atime, 1))
		exit(1);
	if (!msgsok)
		warnx("you have write permission turned off");

	myuid = getuid();

	/* check args */
	switch (argc) {
	case 2:
		search_utmp(argv[1], tty, sizeof tty, mytty, myuid);
		do_write(tty, mytty, myuid);
		break;
	case 3:
		if (!strncmp(argv[2], _PATH_DEV, sizeof(_PATH_DEV) - 1))
			argv[2] += sizeof(_PATH_DEV) - 1;
		if (utmp_chk(argv[1], argv[2]))
			errx(1, "%s is not logged in on %s",
			    argv[1], argv[2]);
		if (term_chk(argv[2], &msgsok, &atime, 1))
			exit(1);
		if (myuid && !msgsok)
			errx(1, "%s has messages disabled on %s",
			    argv[1], argv[2]);
		do_write(argv[2], mytty, myuid);
		break;
	default:
		(void)fprintf(stderr, "usage: write user [ttyname]\n");
		exit(1);
	}
	done(0);

	/* NOTREACHED */
	return (0);
}

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

	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
		return(1);	/* no utmp, cannot talk to users */

	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.
 */
void
search_utmp(char *user, char *tty, int ttyl, char *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)
		err(1, "%s", _PATH_UTMP);

	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)strlcpy(tty, atty, ttyl);
			}
		}

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

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

	(void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
	if (stat(path, &s) < 0) {
		if (showerror)
			warn("%s", path);
		return(1);
	}
	*msgsokP = (s.st_mode & S_IWGRP) != 0;	/* group write bit */
	*atimeP = s.st_atime;
	return(0);
}

/*
 * do_write - actually make the connection
 */
void
do_write(char *tty, char *mytty, uid_t myuid)
{
	char *login, *nows;
	struct passwd *pwd;
	time_t now;
	char path[PATH_MAX], host[HOST_NAME_MAX+1], line[512];
	gid_t gid;
	int fd;

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

	(void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
	fd = open(path, O_WRONLY, 0666);
	if (fd == -1)
		err(1, "open %s", path);
	fflush(stdout);
	if (dup2(fd, STDOUT_FILENO) == -1)
		err(1, "dup2 %s", path);
	if (fd != STDOUT_FILENO)
		close(fd);

	/* revoke privs, now that we have opened the tty */
	gid = getgid();
	if (setresgid(gid, gid, gid) == -1)
		err(1, "setresgid");

	/*
	 * Unfortunately this is rather late - well after utmp
	 * parsing, then pinned by the tty open and setresgid
	 */
	if (pledge("stdio wpath cpath rpath", NULL) == -1)
		err(1, "pledge");

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

	/* print greeting */
	if (gethostname(host, sizeof(host)) < 0)
		(void)strlcpy(host, "???", sizeof host);
	now = time(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(int sig)
{
	(void)write(STDOUT_FILENO, "EOF\r\n", 5);
	if (sig)
		_exit(0);
	else
		exit(0);
}

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

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

	for (; *s != '\0'; ++s) {
		if (*s == '\n') {
			PUTC('\r');
			PUTC('\n');
			continue;
		}
		if (isu8cont(*s))
			continue;
		if (isprint(*s) || isspace(*s) || *s == '\a') {
			PUTC(*s);
		} else {
			PUTC('?');
		}

	}
	return;

err:	err(1, NULL);
#undef PUTC
}

static int
isu8cont(unsigned char c)
{
	return (c & (0x80 | 0x40)) == 0x80;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: write.c,v 1.33 2016/02/05 19:00:39 martijn Exp $ */
2			/* $NetBSD: write.c,v 1.5 1995/08/31 21:48:32 jtc Exp $ */
3
4			/*
5			* Copyright (c) 1989, 1993
6			* The Regents of the University of California. All rights reserved.
7			*
8			* This code is derived from software contributed to Berkeley by
9			* Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory.
10			*
11			* Redistribution and use in source and binary forms, with or without
12			* modification, are permitted provided that the following conditions
13			* are met:
14			* 1. Redistributions of source code must retain the above copyright
15			* notice, this list of conditions and the following disclaimer.
16			* 2. Redistributions in binary form must reproduce the above copyright
17			* notice, this list of conditions and the following disclaimer in the
18			* documentation and/or other materials provided with the distribution.
19			* 3. Neither the name of the University nor the names of its contributors
20			* may be used to endorse or promote products derived from this software
21			* without specific prior written permission.
22			*
23			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33			* SUCH DAMAGE.
34			*/
35
36			#include <sys/stat.h>
37
38			#include <ctype.h>
39			#include <err.h>
40			#include <fcntl.h>
41			#include <limits.h>
42			#include <paths.h>
43			#include <pwd.h>
44			#include <signal.h>
45			#include <stdio.h>
46			#include <stdlib.h>
47			#include <string.h>
48			#include <time.h>
49			#include <unistd.h>
50			#include <utmp.h>
51
52			void done(int sig);
53			void do_write(char , char , uid_t);
54			void wr_fputs(char *);
55			void search_utmp(char , char , int, char *, uid_t);
56			int term_chk(char , int , time_t *, int);
57			int utmp_chk(char , char );
58			static int isu8cont(unsigned char c);
59
60			int
61			main(int argc, char *argv[])
62			{
63			char tty[PATH_MAX], mytty, cp;
64			int msgsok, myttyfd;
65			time_t atime;
66			uid_t myuid;
67
68			/* check that sender has write enabled */
69			if (isatty(fileno(stdin)))
70			myttyfd = fileno(stdin);
71			else if (isatty(fileno(stdout)))
72			myttyfd = fileno(stdout);
73			else if (isatty(fileno(stderr)))
74			myttyfd = fileno(stderr);
75			else
76			errx(1, "can't find your tty");
77			if (!(mytty = ttyname(myttyfd)))
78			errx(1, "can't find your tty's name");
79			if ((cp = strrchr(mytty, '/')))
80			mytty = cp + 1;
81			if (term_chk(mytty, &msgsok, &atime, 1))
82			exit(1);
83			if (!msgsok)
84			warnx("you have write permission turned off");
85
86			myuid = getuid();
87
88			/* check args */
89			switch (argc) {
90			case 2:
91			search_utmp(argv[1], tty, sizeof tty, mytty, myuid);
92			do_write(tty, mytty, myuid);
93			break;
94			case 3:
95			if (!strncmp(argv[2], _PATH_DEV, sizeof(_PATH_DEV) - 1))
96			argv[2] += sizeof(_PATH_DEV) - 1;
97			if (utmp_chk(argv[1], argv[2]))
98			errx(1, "%s is not logged in on %s",
99			argv[1], argv[2]);
100			if (term_chk(argv[2], &msgsok, &atime, 1))
101			exit(1);
102			if (myuid && !msgsok)
103			errx(1, "%s has messages disabled on %s",
104			argv[1], argv[2]);
105			do_write(argv[2], mytty, myuid);
106			break;
107			default:
108			(void)fprintf(stderr, "usage: write user [ttyname]\n");
109			exit(1);
110			}
111			done(0);
112
113			/* NOTREACHED */
114			return (0);
115			}
116
117			/*
118			* utmp_chk - checks that the given user is actually logged in on
119			* the given tty
120			*/
121			int
122			utmp_chk(char user, char tty)
123			{
124			struct utmp u;
125			int ufd;
126
127			if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
128			return(1); /* no utmp, cannot talk to users */
129
130			while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
131			if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
132			strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
133			(void)close(ufd);
134			return(0);
135			}
136
137			(void)close(ufd);
138			return(1);
139			}
140
141			/*
142			* search_utmp - search utmp for the "best" terminal to write to
143			*
144			* Ignores terminals with messages disabled, and of the rest, returns
145			* the one with the most recent access time. Returns as value the number
146			* of the user's terminals with messages enabled, or -1 if the user is
147			* not logged in at all.
148			*
149			* Special case for writing to yourself - ignore the terminal you're
150			* writing from, unless that's the only terminal with messages enabled.
151			*/
152			void
153			search_utmp(char user, char tty, int ttyl, char *mytty, uid_t myuid)
154			{
155			struct utmp u;
156			time_t bestatime, atime;
157			int ufd, nloggedttys, nttys, msgsok, user_is_me;
158			char atty[UT_LINESIZE + 1];
159
160			if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
161			err(1, "%s", _PATH_UTMP);
162
163			nloggedttys = nttys = 0;
164			bestatime = 0;
165			user_is_me = 0;
166			while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
167			if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
168			++nloggedttys;
169			(void)strncpy(atty, u.ut_line, UT_LINESIZE);
170			atty[UT_LINESIZE] = '\0';
171			if (term_chk(atty, &msgsok, &atime, 0))
172			continue; /* bad term? skip */
173			if (myuid && !msgsok)
174			continue; /* skip ttys with msgs off */
175			if (strcmp(atty, mytty) == 0) {
176			user_is_me = 1;
177			continue; /* don't write to yourself */
178			}
179			++nttys;
180			if (atime > bestatime) {
181			bestatime = atime;
182			(void)strlcpy(tty, atty, ttyl);
183			}
184			}
185
186			(void)close(ufd);
187			if (nloggedttys == 0)
188			errx(1, "%s is not logged in", user);
189			if (nttys == 0) {
190			if (user_is_me) { /* ok, so write to yourself! */
191			(void)strlcpy(tty, mytty, ttyl);
192			return;
193			}
194			errx(1, "%s has messages disabled", user);
195			} else if (nttys > 1)
196			warnx("%s is logged in more than once; writing to %s",
197			user, tty);
198			}
199
200			/*
201			* term_chk - check that a terminal exists, and get the message bit
202			* and the access time
203			*/
204			int
205			term_chk(char tty, int msgsokP, time_t *atimeP, int showerror)
206			{
207			struct stat s;
208			char path[PATH_MAX];
209
210			(void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
211			if (stat(path, &s) < 0) {
212			if (showerror)
213			warn("%s", path);
214			return(1);
215			}
216			msgsokP = (s.st_mode & S_IWGRP) != 0; / group write bit */
217			*atimeP = s.st_atime;
218			return(0);
219			}
220
221			/*
222			* do_write - actually make the connection
223			*/
224			void
225			do_write(char tty, char mytty, uid_t myuid)
226			{
227			char login, nows;
228			struct passwd *pwd;
229			time_t now;
230			char path[PATH_MAX], host[HOST_NAME_MAX+1], line[512];
231			gid_t gid;
232			int fd;
233
234			/* Determine our login name before the we reopen() stdout */
235			if ((login = getlogin()) == NULL) {
236			if ((pwd = getpwuid(myuid)))
237			login = pwd->pw_name;
238			else
239			login = "???";
240			}
241
242			(void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty);
243			fd = open(path, O_WRONLY, 0666);
244			if (fd == -1)
245			err(1, "open %s", path);
246			fflush(stdout);
247			if (dup2(fd, STDOUT_FILENO) == -1)
248			err(1, "dup2 %s", path);
249			if (fd != STDOUT_FILENO)
250			close(fd);
251
252			/* revoke privs, now that we have opened the tty */
253			gid = getgid();
254			if (setresgid(gid, gid, gid) == -1)
255			err(1, "setresgid");
256
257			/*
258			* Unfortunately this is rather late - well after utmp
259			* parsing, then pinned by the tty open and setresgid
260			*/
261			if (pledge("stdio wpath cpath rpath", NULL) == -1)
262			err(1, "pledge");
263
264			(void)signal(SIGINT, done);
265			(void)signal(SIGHUP, done);
266
267			/* print greeting */
268			if (gethostname(host, sizeof(host)) < 0)
269			(void)strlcpy(host, "???", sizeof host);
270			now = time(NULL);
271			nows = ctime(&now);
272			nows[16] = '\0';
273			(void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n",
274			login, host, mytty, nows + 11);
275
276			while (fgets(line, sizeof(line), stdin) != NULL)
277			wr_fputs(line);
278			}
279
280			/*
281			* done - cleanup and exit
282			*/
283			void
284			done(int sig)
285			{
286			(void)write(STDOUT_FILENO, "EOF\r\n", 5);
287			if (sig)
288			_exit(0);
289			else
290			exit(0);
291			}
292
293			/*
294			* wr_fputs - like fputs(), but makes control characters visible and
295			* turns \n into \r\n
296			*/
297			void
298			wr_fputs(char *s)
299			{
300
301			#define PUTC(c) if (putchar(c) == EOF) goto err;
302
303			for (; *s != '\0'; ++s) {
304			if (*s == '\n') {
305			PUTC('\r');
306			PUTC('\n');
307			continue;
308			}
309			if (isu8cont(*s))
310			continue;
311			if (isprint(s) \|\| isspace(s) \|\| *s == '\a') {
312			PUTC(*s);
313			} else {
314			PUTC('?');
315			}
316
317			}
318			return;
319
320			err: err(1, NULL);
321			#undef PUTC
322			}
323
324			static int
325			isu8cont(unsigned char c)
326			{
327			return (c & (0x80 \| 0x40)) == 0x80;
328			}