popen.c revision 1.20 
1/*	$OpenBSD: popen.c,v 1.20 2003/12/10 22:57:12 deraadt 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 1.20 2003/12/10 22:57:12 deraadt 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 = (pid_t *)malloc((u_int)(fds * sizeof(pid_t)))) == NULL)
88			return (NULL);
89		memset(pids, 0, fds * sizeof(pid_t));
90	}
91	if (pipe(pdes) < 0)
92		return (NULL);
93
94	/* break up string into pieces */
95	for (argc = 0, cp = program;argc < MAX_ARGV-1; cp = NULL)
96		if (!(argv[argc++] = strtok(cp, " \t\n")))
97			break;
98	argv[MAX_ARGV-1] = NULL;
99
100	/* glob each piece */
101	gargv[0] = argv[0];
102	for (gargc = argc = 1; argv[argc]; argc++) {
103		glob_t gl;
104
105		memset(&gl, 0, sizeof(gl));
106		if (glob(argv[argc],
107		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
108		    NULL, &gl)) {
109			if (gargc < MAX_GARGV-1) {
110				gargv[gargc++] = strdup(argv[argc]);
111				if (gargv[gargc -1] == NULL)
112					fatal ("Out of memory.");
113			}
114
115		} else
116			for (pop = gl.gl_pathv; *pop && gargc < MAX_GARGV-1; pop++) {
117				gargv[gargc++] = strdup(*pop);
118				if (gargv[gargc - 1] == NULL)
119					fatal ("Out of memory.");
120			}
121		globfree(&gl);
122	}
123	gargv[gargc] = NULL;
124
125	iop = NULL;
126
127	switch (pid = fork()) {
128	case -1:			/* error */
129		(void)close(pdes[0]);
130		(void)close(pdes[1]);
131		goto pfree;
132		/* NOTREACHED */
133	case 0:				/* child */
134		if (*type == 'r') {
135			if (pdes[1] != STDOUT_FILENO) {
136				dup2(pdes[1], STDOUT_FILENO);
137				(void)close(pdes[1]);
138			}
139			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
140			(void)close(pdes[0]);
141		} else {
142			if (pdes[0] != STDIN_FILENO) {
143				dup2(pdes[0], STDIN_FILENO);
144				(void)close(pdes[0]);
145			}
146			(void)close(pdes[1]);
147		}
148		closelog();
149
150		if (strcmp(gargv[0], "/bin/ls") == 0) {
151			extern int optreset;
152			extern int ls_main(int, char **);
153
154			/* reset getopt for ls_main */
155			optreset = optind = 1;
156			exit(ls_main(gargc, gargv));
157		}
158
159		execv(gargv[0], gargv);
160		_exit(1);
161	}
162	/* parent; assume fdopen can't fail...  */
163	if (*type == 'r') {
164		iop = fdopen(pdes[0], type);
165		(void)close(pdes[1]);
166	} else {
167		iop = fdopen(pdes[1], type);
168		(void)close(pdes[0]);
169	}
170	pids[fileno(iop)] = pid;
171
172pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
173		free(gargv[argc]);
174
175	return (iop);
176}
177
178int
179ftpd_pclose(FILE *iop)
180{
181	int fdes, status;
182	pid_t pid;
183	sigset_t sigset, osigset;
184
185	/*
186	 * pclose returns -1 if stream is not associated with a
187	 * `popened' command, or, if already `pclosed'.
188	 */
189	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
190		return (-1);
191	(void)fclose(iop);
192	sigemptyset(&sigset);
193	sigaddset(&sigset, SIGINT);
194	sigaddset(&sigset, SIGQUIT);
195	sigaddset(&sigset, SIGHUP);
196	sigprocmask(SIG_BLOCK, &sigset, &osigset);
197	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
198		continue;
199	sigprocmask(SIG_SETMASK, &osigset, NULL);
200	pids[fdes] = 0;
201	if (pid < 0)
202		return (-1);
203	if (WIFEXITED(status))
204		return (WEXITSTATUS(status));
205	return (1);
206}
207