popen.c revision 1.24 
1/*	$OpenBSD: popen.c,v 1.24 2010/03/08 19:34:44 kettenis 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#include <sys/types.h>
38#include <sys/wait.h>
39
40#include <errno.h>
41#include <glob.h>
42#include <signal.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <syslog.h>
47#include <unistd.h>
48
49#include <netinet/in.h>
50
51#include "monitor.h"
52#include "extern.h"
53
54/*
55 * Special version of popen which avoids call to shell.  This ensures noone
56 * may create a pipe to a hidden program as a side effect of a list or dir
57 * command.
58 */
59static pid_t *pids;
60static int fds;
61
62#define MAX_ARGV	100
63#define MAX_GARGV	1000
64
65FILE *
66ftpd_popen(char *program, char *type)
67{
68	char *cp;
69	FILE *iop;
70	int argc, gargc, pdes[2];
71	pid_t pid;
72	char **pop, *argv[MAX_ARGV], *gargv[MAX_GARGV];
73
74	if ((*type != 'r' && *type != 'w') || type[1])
75		return (NULL);
76
77	if (!pids) {
78		if ((fds = getdtablesize()) <= 0)
79			return (NULL);
80		if ((pids = calloc(fds, sizeof(pid_t))) == NULL)
81			return (NULL);
82	}
83	if (pipe(pdes) < 0)
84		return (NULL);
85
86	/* break up string into pieces */
87	for (argc = 0, cp = program;argc < MAX_ARGV-1; cp = NULL)
88		if (!(argv[argc++] = strtok(cp, " \t\n")))
89			break;
90	argv[MAX_ARGV-1] = NULL;
91
92	/* glob each piece */
93	gargv[0] = argv[0];
94	for (gargc = argc = 1; argv[argc]; argc++) {
95		glob_t gl;
96
97		memset(&gl, 0, sizeof(gl));
98		if (glob(argv[argc],
99		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
100		    NULL, &gl)) {
101			if (gargc < MAX_GARGV-1) {
102				gargv[gargc++] = strdup(argv[argc]);
103				if (gargv[gargc -1] == NULL)
104					fatal ("Out of memory.");
105			}
106
107		} else if (gl.gl_pathc > 0) {
108			for (pop = gl.gl_pathv; *pop && gargc < MAX_GARGV-1; pop++) {
109				gargv[gargc++] = strdup(*pop);
110				if (gargv[gargc - 1] == NULL)
111					fatal ("Out of memory.");
112			}
113		}
114		globfree(&gl);
115	}
116	gargv[gargc] = NULL;
117
118	iop = NULL;
119
120	switch (pid = fork()) {
121	case -1:			/* error */
122		(void)close(pdes[0]);
123		(void)close(pdes[1]);
124		goto pfree;
125		/* NOTREACHED */
126	case 0:				/* child */
127		if (*type == 'r') {
128			if (pdes[1] != STDOUT_FILENO) {
129				dup2(pdes[1], STDOUT_FILENO);
130				(void)close(pdes[1]);
131			}
132			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
133			(void)close(pdes[0]);
134		} else {
135			if (pdes[0] != STDIN_FILENO) {
136				dup2(pdes[0], STDIN_FILENO);
137				(void)close(pdes[0]);
138			}
139			(void)close(pdes[1]);
140		}
141		closelog();
142
143		if (strcmp(gargv[0], "/bin/ls") == 0) {
144			extern int optreset;
145			extern int ls_main(int, char **);
146
147			/* reset getopt for ls_main */
148			optreset = optind = 1;
149			exit(ls_main(gargc, gargv));
150		}
151
152		execv(gargv[0], gargv);
153		_exit(1);
154	}
155	/* parent; assume fdopen can't fail...  */
156	if (*type == 'r') {
157		iop = fdopen(pdes[0], type);
158		(void)close(pdes[1]);
159	} else {
160		iop = fdopen(pdes[1], type);
161		(void)close(pdes[0]);
162	}
163	pids[fileno(iop)] = pid;
164
165pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
166		free(gargv[argc]);
167
168	return (iop);
169}
170
171int
172ftpd_pclose(FILE *iop)
173{
174	int fdes, status;
175	pid_t pid;
176	sigset_t sigset, osigset;
177
178	/*
179	 * pclose returns -1 if stream is not associated with a
180	 * `popened' command, or, if already `pclosed'.
181	 */
182	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
183		return (-1);
184	(void)fclose(iop);
185	sigemptyset(&sigset);
186	sigaddset(&sigset, SIGINT);
187	sigaddset(&sigset, SIGQUIT);
188	sigaddset(&sigset, SIGHUP);
189	sigprocmask(SIG_BLOCK, &sigset, &osigset);
190	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
191		continue;
192	sigprocmask(SIG_SETMASK, &osigset, NULL);
193	pids[fdes] = 0;
194	if (pid < 0)
195		return (-1);
196	if (WIFEXITED(status))
197		return (WEXITSTATUS(status));
198	return (1);
199}
200