Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.sbin/cron/do_command.c	Lines:	0	158	0.0 %
Date:	2017-11-07	Branches:	0	128	0.0 %


/*	$OpenBSD: do_command.c,v 1.56 2015/11/17 22:31:44 millert Exp $	*/

/* Copyright 1988,1990,1993,1994 by Paul Vixie
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/wait.h>

#include <bitstring.h>		/* for structs.h */
#include <bsd_auth.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <login_cap.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>		/* for structs.h */
#include <unistd.h>
#include <vis.h>

#include "config.h"
#include "pathnames.h"
#include "macros.h"
#include "structs.h"
#include "funcs.h"

static void		child_process(entry *, user *);

void
do_command(entry *e, user *u)
{

	/* fork to become asynchronous -- parent process is done immediately,
	 * and continues to run the normal cron code, which means return to
	 * tick().  the child and grandchild don't leave this function, alive.
	 *
	 * vfork() is unsuitable, since we have much to do, and the parent
	 * needs to be able to run off and fork other processes.
	 */
	switch (fork()) {
	case -1:
		syslog(LOG_ERR, "(CRON) CAN'T FORK (%m)");
		break;
	case 0:
		/* child process */
		child_process(e, u);
		_exit(EXIT_SUCCESS);
		break;
	default:
		/* parent process */
		break;
	}
}

static void
child_process(entry *e, user *u)
{
	FILE *in;
	int stdin_pipe[2], stdout_pipe[2];
	char **p, *input_data, *usernm;
	auth_session_t *as;
	login_cap_t *lc;
	int children = 0;
	extern char **environ;

	/* mark ourselves as different to PS command watchers */
	setproctitle("running job");

	/* discover some useful and important environment settings
	 */
	usernm = e->pwd->pw_name;

	/* our parent is watching for our death by catching SIGCHLD.  we
	 * do not care to watch for our children's deaths this way -- we
	 * use wait() explicitly.  so we have to reset the signal (which
	 * was inherited from the parent).
	 */
	(void) signal(SIGCHLD, SIG_DFL);

	/* create some pipes to talk to our future child
	 */
	if (pipe(stdin_pipe) != 0 || pipe(stdout_pipe) != 0) {
		syslog(LOG_ERR, "(CRON) PIPE (%m)");
		_exit(EXIT_FAILURE);
	}

	/* since we are a forked process, we can diddle the command string
	 * we were passed -- nobody else is going to use it again, right?
	 *
	 * if a % is present in the command, previous characters are the
	 * command, and subsequent characters are the additional input to
	 * the command.  An escaped % will have the escape character stripped
	 * from it.  Subsequent %'s will be transformed into newlines,
	 * but that happens later.
	 */
	/*local*/{
		int escaped = FALSE;
		int ch;
		char *p;

		for (input_data = p = e->cmd;
		     (ch = *input_data) != '\0';
		     input_data++, p++) {
			if (p != input_data)
				*p = ch;
			if (escaped) {
				if (ch == '%')
					*--p = ch;
				escaped = FALSE;
				continue;
			}
			if (ch == '\\') {
				escaped = TRUE;
				continue;
			}
			if (ch == '%') {
				*input_data++ = '\0';
				break;
			}
		}
		*p = '\0';
	}

	/* fork again, this time so we can exec the user's command.
	 */
	switch (fork()) {
	case -1:
		syslog(LOG_ERR, "(CRON) CAN'T FORK (%m)");
		_exit(EXIT_FAILURE);
		/*NOTREACHED*/
	case 0:
		/* write a log message.  we've waited this long to do it
		 * because it was not until now that we knew the PID that
		 * the actual user command shell was going to get and the
		 * PID is part of the log message.
		 */
		if ((e->flags & DONT_LOG) == 0) {
			char *x;
			if (stravis(&x, e->cmd, 0) != -1) {
				syslog(LOG_INFO, "(%s) CMD (%s)", usernm, x);
				free(x);
			}
		}

		/* get new pgrp, void tty, etc.
		 */
		(void) setsid();

		/* close the pipe ends that we won't use.  this doesn't affect
		 * the parent, who has to read and write them; it keeps the
		 * kernel from recording us as a potential client TWICE --
		 * which would keep it from sending SIGPIPE in otherwise
		 * appropriate circumstances.
		 */
		close(stdin_pipe[WRITE_PIPE]);
		close(stdout_pipe[READ_PIPE]);

		/* grandchild process.  make std{in,out} be the ends of
		 * pipes opened by our daddy; make stderr go to stdout.
		 */
		if (stdin_pipe[READ_PIPE] != STDIN_FILENO) {
			dup2(stdin_pipe[READ_PIPE], STDIN_FILENO);
			close(stdin_pipe[READ_PIPE]);
		}
		if (stdout_pipe[WRITE_PIPE] != STDOUT_FILENO) {
			dup2(stdout_pipe[WRITE_PIPE], STDOUT_FILENO);
			close(stdout_pipe[WRITE_PIPE]);
		}
		dup2(STDOUT_FILENO, STDERR_FILENO);

		/*
		 * From this point on, anything written to stderr will be
		 * mailed to the user as output.
		 */

		/* XXX - should just pass in a login_cap_t * */
		if ((lc = login_getclass(e->pwd->pw_class)) == NULL) {
			warnx("unable to get login class for %s",
			    e->pwd->pw_name);
			syslog(LOG_ERR, "(CRON) CAN'T GET LOGIN CLASS (%s)",
			    e->pwd->pw_name);
			_exit(EXIT_FAILURE);
		}
		if (setusercontext(lc, e->pwd, e->pwd->pw_uid, LOGIN_SETALL) < 0) {
			warn("setusercontext failed for %s", e->pwd->pw_name);
			syslog(LOG_ERR, "(%s) SETUSERCONTEXT FAILED (%m)",
			    e->pwd->pw_name);
			_exit(EXIT_FAILURE);
		}
		as = auth_open();
		if (as == NULL || auth_setpwd(as, e->pwd) != 0) {
			warn("auth_setpwd");
			syslog(LOG_ERR, "(%s) AUTH_SETPWD FAILED (%m)",
			    e->pwd->pw_name);
			_exit(EXIT_FAILURE);
		}
		if (auth_approval(as, lc, usernm, "cron") <= 0) {
			warnx("approval failed for %s", e->pwd->pw_name);
			syslog(LOG_ERR, "(%s) APPROVAL FAILED (cron)",
			    e->pwd->pw_name);
			_exit(EXIT_FAILURE);
		}
		auth_close(as);
		login_close(lc);

		/* If no PATH specified in crontab file but
		 * we just added one via login.conf, add it to
		 * the crontab environment.
		 */
		if (env_get("PATH", e->envp) == NULL && environ != NULL) {
			for (p = environ; *p; p++) {
				if (strncmp(*p, "PATH=", 5) == 0) {
					e->envp = env_set(e->envp, *p);
					break;
				}
			}
		}
		chdir(env_get("HOME", e->envp));

		(void) signal(SIGPIPE, SIG_DFL);

		/*
		 * Exec the command.
		 */
		{
			char	*shell = env_get("SHELL", e->envp);

			execle(shell, shell, "-c", e->cmd, (char *)NULL, e->envp);
			warn("unable to execute %s", shell);
			syslog(LOG_ERR, "(%s) CAN'T EXEC (%s: %m)",
			    e->pwd->pw_name, shell);
			_exit(EXIT_FAILURE);
		}
		break;
	default:
		/* parent process */
		break;
	}

	children++;

	/* middle process, child of original cron, parent of process running
	 * the user's command.
	 */

	/* close the ends of the pipe that will only be referenced in the
	 * grandchild process...
	 */
	close(stdin_pipe[READ_PIPE]);
	close(stdout_pipe[WRITE_PIPE]);

	/*
	 * write, to the pipe connected to child's stdin, any input specified
	 * after a % in the crontab entry.  while we copy, convert any
	 * additional %'s to newlines.  when done, if some characters were
	 * written and the last one wasn't a newline, write a newline.
	 *
	 * Note that if the input data won't fit into one pipe buffer (2K
	 * or 4K on most BSD systems), and the child doesn't read its stdin,
	 * we would block here.  thus we must fork again.
	 */

	if (*input_data && fork() == 0) {
		FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w");
		int need_newline = FALSE;
		int escaped = FALSE;
		int ch;

		/* close the pipe we don't use, since we inherited it and
		 * are part of its reference count now.
		 */
		close(stdout_pipe[READ_PIPE]);

		/* translation:
		 *	\% -> %
		 *	%  -> \n
		 *	\x -> \x	for all x != %
		 */
		while ((ch = *input_data++) != '\0') {
			if (escaped) {
				if (ch != '%')
					putc('\\', out);
			} else {
				if (ch == '%')
					ch = '\n';
			}

			if (!(escaped = (ch == '\\'))) {
				putc(ch, out);
				need_newline = (ch != '\n');
			}
		}
		if (escaped)
			putc('\\', out);
		if (need_newline)
			putc('\n', out);

		/* close the pipe, causing an EOF condition.  fclose causes
		 * stdin_pipe[WRITE_PIPE] to be closed, too.
		 */
		fclose(out);

		_exit(EXIT_SUCCESS);
	}

	/* close the pipe to the grandkiddie's stdin, since its wicked uncle
	 * ernie back there has it open and will close it when he's done.
	 */
	close(stdin_pipe[WRITE_PIPE]);

	children++;

	/*
	 * read output from the grandchild.  it's stderr has been redirected to
	 * it's stdout, which has been redirected to our pipe.  if there is any
	 * output, we'll be mailing it to the user whose crontab this is...
	 * when the grandchild exits, we'll get EOF.
	 */

	(void) signal(SIGPIPE, SIG_IGN);
	in = fdopen(stdout_pipe[READ_PIPE], "r");
	if (in != NULL) {
		int	ch = getc(in);

		if (ch != EOF) {
			FILE	*mail = NULL;
			char	*mailto;
			size_t	bytes = 1;
			int	status = 0;
			pid_t	mailpid;

			/* get name of recipient.  this is MAILTO if set to a
			 * valid local username; USER otherwise.
			 */
			mailto = env_get("MAILTO", e->envp);
			if (!mailto) {
				/* MAILTO not present, set to USER.
				 */
				mailto = usernm;
			} else if (!*mailto || !safe_p(usernm, mailto)) {
				mailto = NULL;
			}

			/* if we are supposed to be mailing, MAILTO will
			 * be non-NULL.  only in this case should we set
			 * up the mail command and subjects and stuff...
			 */

			if (mailto) {
				char	**env;
				char	mailcmd[MAX_COMMAND];
				char	hostname[HOST_NAME_MAX + 1];

				gethostname(hostname, sizeof(hostname));
				if (snprintf(mailcmd, sizeof mailcmd,  MAILFMT,
				    MAILARG) >= sizeof mailcmd) {
					syslog(LOG_ERR,
					    "(%s) ERROR (mailcmd too long)",
					    e->pwd->pw_name);
					(void) _exit(EXIT_FAILURE);
				}
				if (!(mail = cron_popen(mailcmd, "w", e->pwd,
				    &mailpid))) {
					syslog(LOG_ERR, "(%s) POPEN (%s)",
					    e->pwd->pw_name, mailcmd);
					(void) _exit(EXIT_FAILURE);
				}
				fprintf(mail, "From: root (Cron Daemon)\n");
				fprintf(mail, "To: %s\n", mailto);
				fprintf(mail, "Subject: Cron <%s@%s> %s\n",
					usernm, first_word(hostname, "."),
					e->cmd);
				fprintf(mail, "Auto-Submitted: auto-generated\n");
				for (env = e->envp;  *env;  env++)
					fprintf(mail, "X-Cron-Env: <%s>\n",
						*env);
				fprintf(mail, "\n");

				/* this was the first char from the pipe
				 */
				fputc(ch, mail);
			}

			/* we have to read the input pipe no matter whether
			 * we mail or not, but obviously we only write to
			 * mail pipe if we ARE mailing.
			 */

			while (EOF != (ch = getc(in))) {
				bytes++;
				if (mail)
					fputc(ch, mail);
			}

			/* only close pipe if we opened it -- i.e., we're
			 * mailing...
			 */

			if (mail) {
				/* Note: the pclose will probably see
				 * the termination of the grandchild
				 * in addition to the mail process, since
				 * it (the grandchild) is likely to exit
				 * after closing its stdout.
				 */
				status = cron_pclose(mail, mailpid);
			}

			/* if there was output and we could not mail it,
			 * log the facts so the poor user can figure out
			 * what's going on.
			 */
			if (mail && status) {
				syslog(LOG_NOTICE, "(%s) MAIL (mailed %zu byte"
				"%s of output but got status 0x%04x)", usernm,
				bytes, (bytes == 1) ? "" : "s", status);
			}

		} /*if data from grandchild*/

		fclose(in);	/* also closes stdout_pipe[READ_PIPE] */
	}

	/* wait for children to die.
	 */
	for (; children > 0; children--) {
		int waiter;
		pid_t pid;

		while ((pid = wait(&waiter)) < 0 && errno == EINTR)
			;
		if (pid < 0) {
			break;
		}
		/*
		if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
			Debug(DPROC, (", dumped core"))
		*/
	}
}

int
safe_p(const char *usernm, const char *s)
{
	static const char safe_delim[] = "@!:%+-.,";     /* conservative! */
	const char *t;
	int ch, first;

	for (t = s, first = 1; (ch = (unsigned char)*t++) != '\0'; first = 0) {
		if (isascii(ch) && isprint(ch) &&
		    (isalnum(ch) || ch == '_' ||
		    (!first && strchr(safe_delim, ch))))
			continue;
		syslog(LOG_WARNING, "(%s) UNSAFE (%s)", usernm, s);
		return (FALSE);
	}
	return (TRUE);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: do_command.c,v 1.56 2015/11/17 22:31:44 millert Exp $ */
2
3			/* Copyright 1988,1990,1993,1994 by Paul Vixie
4			* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5			* Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
6			*
7			* Permission to use, copy, modify, and distribute this software for any
8			* purpose with or without fee is hereby granted, provided that the above
9			* copyright notice and this permission notice appear in all copies.
10			*
11			* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
14			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17			* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18			*/
19
20			#include <sys/types.h>
21			#include <sys/wait.h>
22
23			#include <bitstring.h> /* for structs.h */
24			#include <bsd_auth.h>
25			#include <ctype.h>
26			#include <err.h>
27			#include <errno.h>
28			#include <fcntl.h>
29			#include <limits.h>
30			#include <login_cap.h>
31			#include <pwd.h>
32			#include <signal.h>
33			#include <stdio.h>
34			#include <stdlib.h>
35			#include <string.h>
36			#include <syslog.h>
37			#include <time.h> /* for structs.h */
38			#include <unistd.h>
39			#include <vis.h>
40
41			#include "config.h"
42			#include "pathnames.h"
43			#include "macros.h"
44			#include "structs.h"
45			#include "funcs.h"
46
47			static void child_process(entry , user );
48
49			void
50			do_command(entry e, user u)
51			{
52
53			/* fork to become asynchronous -- parent process is done immediately,
54			* and continues to run the normal cron code, which means return to
55			* tick(). the child and grandchild don't leave this function, alive.
56			*
57			* vfork() is unsuitable, since we have much to do, and the parent
58			* needs to be able to run off and fork other processes.
59			*/
60			switch (fork()) {
61			case -1:
62			syslog(LOG_ERR, "(CRON) CAN'T FORK (%m)");
63			break;
64			case 0:
65			/* child process */
66			child_process(e, u);
67			_exit(EXIT_SUCCESS);
68			break;
69			default:
70			/* parent process */
71			break;
72			}
73			}
74
75			static void
76			child_process(entry e, user u)
77			{
78			FILE *in;
79			int stdin_pipe[2], stdout_pipe[2];
80			char *p, input_data, *usernm;
81			auth_session_t *as;
82			login_cap_t *lc;
83			int children = 0;
84			extern char **environ;
85
86			/* mark ourselves as different to PS command watchers */
87			setproctitle("running job");
88
89			/* discover some useful and important environment settings
90			*/
91			usernm = e->pwd->pw_name;
92
93			/* our parent is watching for our death by catching SIGCHLD. we
94			* do not care to watch for our children's deaths this way -- we
95			* use wait() explicitly. so we have to reset the signal (which
96			* was inherited from the parent).
97			*/
98			(void) signal(SIGCHLD, SIG_DFL);
99
100			/* create some pipes to talk to our future child
101			*/
102			if (pipe(stdin_pipe) != 0 \|\| pipe(stdout_pipe) != 0) {
103			syslog(LOG_ERR, "(CRON) PIPE (%m)");
104			_exit(EXIT_FAILURE);
105			}
106
107			/* since we are a forked process, we can diddle the command string
108			* we were passed -- nobody else is going to use it again, right?
109			*
110			* if a % is present in the command, previous characters are the
111			* command, and subsequent characters are the additional input to
112			* the command. An escaped % will have the escape character stripped
113			* from it. Subsequent %'s will be transformed into newlines,
114			* but that happens later.
115			*/
116			/local/{
117			int escaped = FALSE;
118			int ch;
119			char *p;
120
121			for (input_data = p = e->cmd;
122			(ch = *input_data) != '\0';
123			input_data++, p++) {
124			if (p != input_data)
125			*p = ch;
126			if (escaped) {
127			if (ch == '%')
128			*--p = ch;
129			escaped = FALSE;
130			continue;
131			}
132			if (ch == '\\') {
133			escaped = TRUE;
134			continue;
135			}
136			if (ch == '%') {
137			*input_data++ = '\0';
138			break;
139			}
140			}
141			*p = '\0';
142			}
143
144			/* fork again, this time so we can exec the user's command.
145			*/
146			switch (fork()) {
147			case -1:
148			syslog(LOG_ERR, "(CRON) CAN'T FORK (%m)");
149			_exit(EXIT_FAILURE);
150			/NOTREACHED/
151			case 0:
152			/* write a log message. we've waited this long to do it
153			* because it was not until now that we knew the PID that
154			* the actual user command shell was going to get and the
155			* PID is part of the log message.
156			*/
157			if ((e->flags & DONT_LOG) == 0) {
158			char *x;
159			if (stravis(&x, e->cmd, 0) != -1) {
160			syslog(LOG_INFO, "(%s) CMD (%s)", usernm, x);
161			free(x);
162			}
163			}
164
165			/* get new pgrp, void tty, etc.
166			*/
167			(void) setsid();
168
169			/* close the pipe ends that we won't use. this doesn't affect
170			* the parent, who has to read and write them; it keeps the
171			* kernel from recording us as a potential client TWICE --
172			* which would keep it from sending SIGPIPE in otherwise
173			* appropriate circumstances.
174			*/
175			close(stdin_pipe[WRITE_PIPE]);
176			close(stdout_pipe[READ_PIPE]);
177
178			/* grandchild process. make std{in,out} be the ends of
179			* pipes opened by our daddy; make stderr go to stdout.
180			*/
181			if (stdin_pipe[READ_PIPE] != STDIN_FILENO) {
182			dup2(stdin_pipe[READ_PIPE], STDIN_FILENO);
183			close(stdin_pipe[READ_PIPE]);
184			}
185			if (stdout_pipe[WRITE_PIPE] != STDOUT_FILENO) {
186			dup2(stdout_pipe[WRITE_PIPE], STDOUT_FILENO);
187			close(stdout_pipe[WRITE_PIPE]);
188			}
189			dup2(STDOUT_FILENO, STDERR_FILENO);
190
191			/*
192			* From this point on, anything written to stderr will be
193			* mailed to the user as output.
194			*/
195
196			/* XXX - should just pass in a login_cap_t * */
197			if ((lc = login_getclass(e->pwd->pw_class)) == NULL) {
198			warnx("unable to get login class for %s",
199			e->pwd->pw_name);
200			syslog(LOG_ERR, "(CRON) CAN'T GET LOGIN CLASS (%s)",
201			e->pwd->pw_name);
202			_exit(EXIT_FAILURE);
203			}
204			if (setusercontext(lc, e->pwd, e->pwd->pw_uid, LOGIN_SETALL) < 0) {
205			warn("setusercontext failed for %s", e->pwd->pw_name);
206			syslog(LOG_ERR, "(%s) SETUSERCONTEXT FAILED (%m)",
207			e->pwd->pw_name);
208			_exit(EXIT_FAILURE);
209			}
210			as = auth_open();
211			if (as == NULL \|\| auth_setpwd(as, e->pwd) != 0) {
212			warn("auth_setpwd");
213			syslog(LOG_ERR, "(%s) AUTH_SETPWD FAILED (%m)",
214			e->pwd->pw_name);
215			_exit(EXIT_FAILURE);
216			}
217			if (auth_approval(as, lc, usernm, "cron") <= 0) {
218			warnx("approval failed for %s", e->pwd->pw_name);
219			syslog(LOG_ERR, "(%s) APPROVAL FAILED (cron)",
220			e->pwd->pw_name);
221			_exit(EXIT_FAILURE);
222			}
223			auth_close(as);
224			login_close(lc);
225
226			/* If no PATH specified in crontab file but
227			* we just added one via login.conf, add it to
228			* the crontab environment.
229			*/
230			if (env_get("PATH", e->envp) == NULL && environ != NULL) {
231			for (p = environ; *p; p++) {
232			if (strncmp(*p, "PATH=", 5) == 0) {
233			e->envp = env_set(e->envp, *p);
234			break;
235			}
236			}
237			}
238			chdir(env_get("HOME", e->envp));
239
240			(void) signal(SIGPIPE, SIG_DFL);
241
242			/*
243			* Exec the command.
244			*/
245			{
246			char *shell = env_get("SHELL", e->envp);
247
248			execle(shell, shell, "-c", e->cmd, (char *)NULL, e->envp);
249			warn("unable to execute %s", shell);
250			syslog(LOG_ERR, "(%s) CAN'T EXEC (%s: %m)",
251			e->pwd->pw_name, shell);
252			_exit(EXIT_FAILURE);
253			}
254			break;
255			default:
256			/* parent process */
257			break;
258			}
259
260			children++;
261
262			/* middle process, child of original cron, parent of process running
263			* the user's command.
264			*/
265
266			/* close the ends of the pipe that will only be referenced in the
267			* grandchild process...
268			*/
269			close(stdin_pipe[READ_PIPE]);
270			close(stdout_pipe[WRITE_PIPE]);
271
272			/*
273			* write, to the pipe connected to child's stdin, any input specified
274			* after a % in the crontab entry. while we copy, convert any
275			* additional %'s to newlines. when done, if some characters were
276			* written and the last one wasn't a newline, write a newline.
277			*
278			* Note that if the input data won't fit into one pipe buffer (2K
279			* or 4K on most BSD systems), and the child doesn't read its stdin,
280			* we would block here. thus we must fork again.
281			*/
282
283			if (*input_data && fork() == 0) {
284			FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w");
285			int need_newline = FALSE;
286			int escaped = FALSE;
287			int ch;
288
289			/* close the pipe we don't use, since we inherited it and
290			* are part of its reference count now.
291			*/
292			close(stdout_pipe[READ_PIPE]);
293
294			/* translation:
295			* \% -> %
296			* % -> \n
297			* \x -> \x for all x != %
298			*/
299			while ((ch = *input_data++) != '\0') {
300			if (escaped) {
301			if (ch != '%')
302			putc('\\', out);
303			} else {
304			if (ch == '%')
305			ch = '\n';
306			}
307
308			if (!(escaped = (ch == '\\'))) {
309			putc(ch, out);
310			need_newline = (ch != '\n');
311			}
312			}
313			if (escaped)
314			putc('\\', out);
315			if (need_newline)
316			putc('\n', out);
317
318			/* close the pipe, causing an EOF condition. fclose causes
319			* stdin_pipe[WRITE_PIPE] to be closed, too.
320			*/
321			fclose(out);
322
323			_exit(EXIT_SUCCESS);
324			}
325
326			/* close the pipe to the grandkiddie's stdin, since its wicked uncle
327			* ernie back there has it open and will close it when he's done.
328			*/
329			close(stdin_pipe[WRITE_PIPE]);
330
331			children++;
332
333			/*
334			* read output from the grandchild. it's stderr has been redirected to
335			* it's stdout, which has been redirected to our pipe. if there is any
336			* output, we'll be mailing it to the user whose crontab this is...
337			* when the grandchild exits, we'll get EOF.
338			*/
339
340			(void) signal(SIGPIPE, SIG_IGN);
341			in = fdopen(stdout_pipe[READ_PIPE], "r");
342			if (in != NULL) {
343			int ch = getc(in);
344
345			if (ch != EOF) {
346			FILE *mail = NULL;
347			char *mailto;
348			size_t bytes = 1;
349			int status = 0;
350			pid_t mailpid;
351
352			/* get name of recipient. this is MAILTO if set to a
353			* valid local username; USER otherwise.
354			*/
355			mailto = env_get("MAILTO", e->envp);
356			if (!mailto) {
357			/* MAILTO not present, set to USER.
358			*/
359			mailto = usernm;
360			} else if (!*mailto \|\| !safe_p(usernm, mailto)) {
361			mailto = NULL;
362			}
363
364			/* if we are supposed to be mailing, MAILTO will
365			* be non-NULL. only in this case should we set
366			* up the mail command and subjects and stuff...
367			*/
368
369			if (mailto) {
370			char **env;
371			char mailcmd[MAX_COMMAND];
372			char hostname[HOST_NAME_MAX + 1];
373
374			gethostname(hostname, sizeof(hostname));
375			if (snprintf(mailcmd, sizeof mailcmd, MAILFMT,
376			MAILARG) >= sizeof mailcmd) {
377			syslog(LOG_ERR,
378			"(%s) ERROR (mailcmd too long)",
379			e->pwd->pw_name);
380			(void) _exit(EXIT_FAILURE);
381			}
382			if (!(mail = cron_popen(mailcmd, "w", e->pwd,
383			&mailpid))) {
384			syslog(LOG_ERR, "(%s) POPEN (%s)",
385			e->pwd->pw_name, mailcmd);
386			(void) _exit(EXIT_FAILURE);
387			}
388			fprintf(mail, "From: root (Cron Daemon)\n");
389			fprintf(mail, "To: %s\n", mailto);
390			fprintf(mail, "Subject: Cron <%s@%s> %s\n",
391			usernm, first_word(hostname, "."),
392			e->cmd);
393			fprintf(mail, "Auto-Submitted: auto-generated\n");
394			for (env = e->envp; *env; env++)
395			fprintf(mail, "X-Cron-Env: <%s>\n",
396			*env);
397			fprintf(mail, "\n");
398
399			/* this was the first char from the pipe
400			*/
401			fputc(ch, mail);
402			}
403
404			/* we have to read the input pipe no matter whether
405			* we mail or not, but obviously we only write to
406			* mail pipe if we ARE mailing.
407			*/
408
409			while (EOF != (ch = getc(in))) {
410			bytes++;
411			if (mail)
412			fputc(ch, mail);
413			}
414
415			/* only close pipe if we opened it -- i.e., we're
416			* mailing...
417			*/
418
419			if (mail) {
420			/* Note: the pclose will probably see
421			* the termination of the grandchild
422			* in addition to the mail process, since
423			* it (the grandchild) is likely to exit
424			* after closing its stdout.
425			*/
426			status = cron_pclose(mail, mailpid);
427			}
428
429			/* if there was output and we could not mail it,
430			* log the facts so the poor user can figure out
431			* what's going on.
432			*/
433			if (mail && status) {
434			syslog(LOG_NOTICE, "(%s) MAIL (mailed %zu byte"
435			"%s of output but got status 0x%04x)", usernm,
436			bytes, (bytes == 1) ? "" : "s", status);
437			}
438
439			} /if data from grandchild/
440
441			fclose(in); /* also closes stdout_pipe[READ_PIPE] */
442			}
443
444			/* wait for children to die.
445			*/
446			for (; children > 0; children--) {
447			int waiter;
448			pid_t pid;
449
450			while ((pid = wait(&waiter)) < 0 && errno == EINTR)
451			;
452			if (pid < 0) {
453			break;
454			}
455			/*
456			if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
457			Debug(DPROC, (", dumped core"))
458			*/
459			}
460			}
461
462			int
463			safe_p(const char usernm, const char s)
464			{
465			static const char safe_delim[] = "@!:%+-.,"; /* conservative! */
466			const char *t;
467			int ch, first;
468
469			for (t = s, first = 1; (ch = (unsigned char)*t++) != '\0'; first = 0) {
470			if (isascii(ch) && isprint(ch) &&
471			(isalnum(ch) \|\| ch == '_' \|\|
472			(!first && strchr(safe_delim, ch))))
473			continue;
474			syslog(LOG_WARNING, "(%s) UNSAFE (%s)", usernm, s);
475			return (FALSE);
476			}
477			return (TRUE);
478			}