popen.c revision 1.21 
1/*	$OpenBSD: popen.c,v 1.21 2006/04/02 21:38:56 djm 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 1.21 2006/04/02 21:38:56 djm 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#include "extern.h"
60
61/*
62 * Special version of popen which avoids call to shell.  This ensures noone
63 * may create a pipe to a hidden program as a side effect of a list or dir
64 * command.
65 */
66static pid_t *pids;
67static int fds;
68
69#define MAX_ARGV	100
70#define MAX_GARGV	1000
71
72FILE *
73ftpd_popen(char *program, char *type)
74{
75	char *cp;
76	FILE *iop;
77	int argc, gargc, pdes[2];
78	pid_t pid;
79	char **pop, *argv[MAX_ARGV], *gargv[MAX_GARGV];
80
81	if ((*type != 'r' && *type != 'w') || type[1])
82		return (NULL);
83
84	if (!pids) {
85		if ((fds = getdtablesize()) <= 0)
86			return (NULL);
87		if ((pids = calloc(fds, sizeof(pid_t))) == NULL)
88			return (NULL);
89	}
90	if (pipe(pdes) < 0)
91		return (NULL);
92
93	/* break up string into pieces */
94	for (argc = 0, cp = program;argc < MAX_ARGV-1; cp = NULL)
95		if (!(argv[argc++] = strtok(cp, " \t\n")))
96			break;
97	argv[MAX_ARGV-1] = NULL;
98
99	/* glob each piece */
100	gargv[0] = argv[0];
101	for (gargc = argc = 1; argv[argc]; argc++) {
102		glob_t gl;
103
104		memset(&gl, 0, sizeof(gl));
105		if (glob(argv[argc],
106		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
107		    NULL, &gl)) {
108			if (gargc < MAX_GARGV-1) {
109				gargv[gargc++] = strdup(argv[argc]);
110				if (gargv[gargc -1] == NULL)
111					fatal ("Out of memory.");
112			}
113
114		} else
115			for (pop = gl.gl_pathv; *pop && gargc < MAX_GARGV-1; pop++) {
116				gargv[gargc++] = strdup(*pop);
117				if (gargv[gargc - 1] == NULL)
118					fatal ("Out of memory.");
119			}
120		globfree(&gl);
121	}
122	gargv[gargc] = NULL;
123
124	iop = NULL;
125
126	switch (pid = fork()) {
127	case -1:			/* error */
128		(void)close(pdes[0]);
129		(void)close(pdes[1]);
130		goto pfree;
131		/* NOTREACHED */
132	case 0:				/* child */
133		if (*type == 'r') {
134			if (pdes[1] != STDOUT_FILENO) {
135				dup2(pdes[1], STDOUT_FILENO);
136				(void)close(pdes[1]);
137			}
138			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
139			(void)close(pdes[0]);
140		} else {
141			if (pdes[0] != STDIN_FILENO) {
142				dup2(pdes[0], STDIN_FILENO);
143				(void)close(pdes[0]);
144			}
145			(void)close(pdes[1]);
146		}
147		closelog();
148
149		if (strcmp(gargv[0], "/bin/ls") == 0) {
150			extern int optreset;
151			extern int ls_main(int, char **);
152
153			/* reset getopt for ls_main */
154			optreset = optind = 1;
155			exit(ls_main(gargc, gargv));
156		}
157
158		execv(gargv[0], gargv);
159		_exit(1);
160	}
161	/* parent; assume fdopen can't fail...  */
162	if (*type == 'r') {
163		iop = fdopen(pdes[0], type);
164		(void)close(pdes[1]);
165	} else {
166		iop = fdopen(pdes[1], type);
167		(void)close(pdes[0]);
168	}
169	pids[fileno(iop)] = pid;
170
171pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
172		free(gargv[argc]);
173
174	return (iop);
175}
176
177int
178ftpd_pclose(FILE *iop)
179{
180	int fdes, status;
181	pid_t pid;
182	sigset_t sigset, osigset;
183
184	/*
185	 * pclose returns -1 if stream is not associated with a
186	 * `popened' command, or, if already `pclosed'.
187	 */
188	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
189		return (-1);
190	(void)fclose(iop);
191	sigemptyset(&sigset);
192	sigaddset(&sigset, SIGINT);
193	sigaddset(&sigset, SIGQUIT);
194	sigaddset(&sigset, SIGHUP);
195	sigprocmask(SIG_BLOCK, &sigset, &osigset);
196	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
197		continue;
198	sigprocmask(SIG_SETMASK, &osigset, NULL);
199	pids[fdes] = 0;
200	if (pid < 0)
201		return (-1);
202	if (WIFEXITED(status))
203		return (WEXITSTATUS(status));
204	return (1);
205}
206