popen.c revision 1.22 
1/*	$OpenBSD: popen.c,v 1.22 2008/06/30 12:03:51 ragge Exp $	*/
2/*	$NetBSD: popen.c,v 1.5 1995/04/11 02:45:00 cgd Exp $	*/
3
4/*
5 * Copyright (c) 1988, 1993, 1994
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software written by Ken Arnold and
9 * published in UNIX Review, Vol. 6, No. 8.
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
37#ifndef lint
38#if 0
39static const char sccsid[] = "@(#)popen.c	8.3 (Berkeley) 4/6/94";
40#else
41static const char rcsid[] =
42    "$OpenBSD: popen.c,v 1.22 2008/06/30 12:03:51 ragge Exp $";
43#endif
44#endif /* not lint */
45
46#include <sys/types.h>
47#include <sys/wait.h>
48
49#include <errno.h>
50#include <glob.h>
51#include <signal.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <syslog.h>
56#include <unistd.h>
57
58#include <netinet/in.h>
59
60#include "monitor.h"
61#include "extern.h"
62
63/*
64 * Special version of popen which avoids call to shell.  This ensures noone
65 * may create a pipe to a hidden program as a side effect of a list or dir
66 * command.
67 */
68static pid_t *pids;
69static int fds;
70
71#define MAX_ARGV	100
72#define MAX_GARGV	1000
73
74FILE *
75ftpd_popen(char *program, char *type)
76{
77	char *cp;
78	FILE *iop;
79	int argc, gargc, pdes[2];
80	pid_t pid;
81	char **pop, *argv[MAX_ARGV], *gargv[MAX_GARGV];
82
83	if ((*type != 'r' && *type != 'w') || type[1])
84		return (NULL);
85
86	if (!pids) {
87		if ((fds = getdtablesize()) <= 0)
88			return (NULL);
89		if ((pids = calloc(fds, sizeof(pid_t))) == NULL)
90			return (NULL);
91	}
92	if (pipe(pdes) < 0)
93		return (NULL);
94
95	/* break up string into pieces */
96	for (argc = 0, cp = program;argc < MAX_ARGV-1; cp = NULL)
97		if (!(argv[argc++] = strtok(cp, " \t\n")))
98			break;
99	argv[MAX_ARGV-1] = NULL;
100
101	/* glob each piece */
102	gargv[0] = argv[0];
103	for (gargc = argc = 1; argv[argc]; argc++) {
104		glob_t gl;
105
106		memset(&gl, 0, sizeof(gl));
107		if (glob(argv[argc],
108		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
109		    NULL, &gl)) {
110			if (gargc < MAX_GARGV-1) {
111				gargv[gargc++] = strdup(argv[argc]);
112				if (gargv[gargc -1] == NULL)
113					fatal ("Out of memory.");
114			}
115
116		} else
117			for (pop = gl.gl_pathv; *pop && gargc < MAX_GARGV-1; pop++) {
118				gargv[gargc++] = strdup(*pop);
119				if (gargv[gargc - 1] == NULL)
120					fatal ("Out of memory.");
121			}
122		globfree(&gl);
123	}
124	gargv[gargc] = NULL;
125
126	iop = NULL;
127
128	switch (pid = fork()) {
129	case -1:			/* error */
130		(void)close(pdes[0]);
131		(void)close(pdes[1]);
132		goto pfree;
133		/* NOTREACHED */
134	case 0:				/* child */
135		if (*type == 'r') {
136			if (pdes[1] != STDOUT_FILENO) {
137				dup2(pdes[1], STDOUT_FILENO);
138				(void)close(pdes[1]);
139			}
140			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
141			(void)close(pdes[0]);
142		} else {
143			if (pdes[0] != STDIN_FILENO) {
144				dup2(pdes[0], STDIN_FILENO);
145				(void)close(pdes[0]);
146			}
147			(void)close(pdes[1]);
148		}
149		closelog();
150
151		if (strcmp(gargv[0], "/bin/ls") == 0) {
152			extern int optreset;
153			extern int ls_main(int, char **);
154
155			/* reset getopt for ls_main */
156			optreset = optind = 1;
157			exit(ls_main(gargc, gargv));
158		}
159
160		execv(gargv[0], gargv);
161		_exit(1);
162	}
163	/* parent; assume fdopen can't fail...  */
164	if (*type == 'r') {
165		iop = fdopen(pdes[0], type);
166		(void)close(pdes[1]);
167	} else {
168		iop = fdopen(pdes[1], type);
169		(void)close(pdes[0]);
170	}
171	pids[fileno(iop)] = pid;
172
173pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
174		free(gargv[argc]);
175
176	return (iop);
177}
178
179int
180ftpd_pclose(FILE *iop)
181{
182	int fdes, status;
183	pid_t pid;
184	sigset_t sigset, osigset;
185
186	/*
187	 * pclose returns -1 if stream is not associated with a
188	 * `popened' command, or, if already `pclosed'.
189	 */
190	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
191		return (-1);
192	(void)fclose(iop);
193	sigemptyset(&sigset);
194	sigaddset(&sigset, SIGINT);
195	sigaddset(&sigset, SIGQUIT);
196	sigaddset(&sigset, SIGHUP);
197	sigprocmask(SIG_BLOCK, &sigset, &osigset);
198	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
199		continue;
200	sigprocmask(SIG_SETMASK, &osigset, NULL);
201	pids[fdes] = 0;
202	if (pid < 0)
203		return (-1);
204	if (WIFEXITED(status))
205		return (WEXITSTATUS(status));
206	return (1);
207}
208