popen.c revision 1.4 
1/*	$OpenBSD: popen.c,v 1.4 1996/07/30 02:01:16 downsj 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. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 */
40
41#ifndef lint
42#if 0
43static char sccsid[] = "@(#)popen.c	8.3 (Berkeley) 4/6/94";
44#else
45static char rcsid[] = "$NetBSD: popen.c,v 1.5 1995/04/11 02:45:00 cgd Exp $";
46#endif
47#endif /* not lint */
48
49#include <sys/types.h>
50#include <sys/wait.h>
51
52#include <errno.h>
53#include <glob.h>
54#include <signal.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <syslog.h>
59#include <unistd.h>
60
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 int *pids;
69static int fds;
70
71FILE *
72ftpd_popen(program, type)
73	char *program, *type;
74{
75	char *cp;
76	FILE *iop;
77	int argc, gargc, pdes[2], pid;
78	char **pop, *argv[100], *gargv[1000];
79
80	if (*type != 'r' && *type != 'w' || type[1])
81		return (NULL);
82
83	if (!pids) {
84		if ((fds = getdtablesize()) <= 0)
85			return (NULL);
86		if ((pids = (int *)malloc((u_int)(fds * sizeof(int)))) == NULL)
87			return (NULL);
88		memset(pids, 0, fds * sizeof(int));
89	}
90	if (pipe(pdes) < 0)
91		return (NULL);
92
93	/* break up string into pieces */
94	for (argc = 0, cp = program;argc < 100; cp = NULL)
95		if (!(argv[argc++] = strtok(cp, " \t\n")))
96			break;
97
98	/* glob each piece */
99	gargv[0] = argv[0];
100	for (gargc = argc = 1; argv[argc]; argc++) {
101		glob_t gl;
102		int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE;
103
104		memset(&gl, 0, sizeof(gl));
105		if (glob(argv[argc], flags, NULL, &gl))
106			gargv[gargc++] = strdup(argv[argc]);
107		else
108			for (pop = gl.gl_pathv; *pop && gargc < 1000; pop++)
109				gargv[gargc++] = strdup(*pop);
110		globfree(&gl);
111	}
112	gargv[gargc] = NULL;
113
114	iop = NULL;
115	switch(pid = vfork()) {
116	case -1:			/* error */
117		(void)close(pdes[0]);
118		(void)close(pdes[1]);
119		goto pfree;
120		/* NOTREACHED */
121	case 0:				/* child */
122		if (*type == 'r') {
123			if (pdes[1] != STDOUT_FILENO) {
124				dup2(pdes[1], STDOUT_FILENO);
125				(void)close(pdes[1]);
126			}
127			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
128			(void)close(pdes[0]);
129		} else {
130			if (pdes[0] != STDIN_FILENO) {
131				dup2(pdes[0], STDIN_FILENO);
132				(void)close(pdes[0]);
133			}
134			(void)close(pdes[1]);
135		}
136		closelog();
137
138		execv(gargv[0], gargv);
139		_exit(1);
140	}
141	/* parent; assume fdopen can't fail...  */
142	if (*type == 'r') {
143		iop = fdopen(pdes[0], type);
144		(void)close(pdes[1]);
145	} else {
146		iop = fdopen(pdes[1], type);
147		(void)close(pdes[0]);
148	}
149	pids[fileno(iop)] = pid;
150
151pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
152		free(gargv[argc]);
153
154	return (iop);
155}
156
157int
158ftpd_pclose(iop)
159	FILE *iop;
160{
161	int fdes, omask, status;
162	pid_t pid;
163	sigset_t sigset, osigset;
164
165	/*
166	 * pclose returns -1 if stream is not associated with a
167	 * `popened' command, or, if already `pclosed'.
168	 */
169	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
170		return (-1);
171	(void)fclose(iop);
172	sigemptyset(&sigset);
173	sigaddset(&sigset, SIGINT);
174	sigaddset(&sigset, SIGQUIT);
175	sigaddset(&sigset, SIGHUP);
176	sigprocmask(SIG_BLOCK, &sigset, &osigset);
177	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
178		continue;
179	sigprocmask(SIG_SETMASK, &osigset, NULL);
180	pids[fdes] = 0;
181	if (pid < 0)
182		return (pid);
183	if (WIFEXITED(status))
184		return (WEXITSTATUS(status));
185	return (1);
186}
187