1/*
2 * Copyright (c) 1988, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software written by Ken Arnold and
6 * published in UNIX Review, Vol. 6, No. 8.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)popen.c	8.3 (Berkeley) 4/6/94";
36#endif
37#endif /* not lint */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD$");
41
42#include <sys/types.h>
43#include <sys/wait.h>
44#include <netinet/in.h>
45
46#include <errno.h>
47#include <glob.h>
48#include <signal.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <string.h>
52#include <unistd.h>
53
54#include "extern.h"
55#include "pathnames.h"
56#include <syslog.h>
57#include <time.h>
58
59#define	MAXUSRARGS	100
60#define	MAXGLOBARGS	1000
61
62/*
63 * Special version of popen which avoids call to shell.  This ensures no one
64 * may create a pipe to a hidden program as a side effect of a list or dir
65 * command.
66 */
67static int *pids;
68static int fds;
69
70FILE *
71ftpd_popen(char *program, char *type)
72{
73	char *cp;
74	FILE *iop;
75	int argc, gargc, pdes[2], pid;
76	char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS];
77
78	if (((*type != 'r') && (*type != 'w')) || type[1])
79		return (NULL);
80
81	if (!pids) {
82		if ((fds = getdtablesize()) <= 0)
83			return (NULL);
84		if ((pids = calloc(fds, sizeof(int))) == NULL)
85			return (NULL);
86	}
87	if (pipe(pdes) < 0)
88		return (NULL);
89
90	/* break up string into pieces */
91	for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) {
92		if (!(argv[argc++] = strtok(cp, " \t\n")))
93			break;
94	}
95	argv[argc - 1] = NULL;
96
97	/* glob each piece */
98	gargv[0] = argv[0];
99	for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) {
100		glob_t gl;
101		int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE;
102
103		memset(&gl, 0, sizeof(gl));
104		gl.gl_matchc = MAXGLOBARGS;
105		flags |= GLOB_LIMIT;
106		if (glob(argv[argc], flags, NULL, &gl))
107			gargv[gargc++] = strdup(argv[argc]);
108		else if (gl.gl_pathc > 0) {
109			for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1);
110			     pop++)
111				gargv[gargc++] = strdup(*pop);
112		}
113		globfree(&gl);
114	}
115	gargv[gargc] = NULL;
116
117	iop = NULL;
118	fflush(NULL);
119	pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork();
120	switch(pid) {
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		/* Drop privileges before proceeding */
142		if (getuid() != geteuid() && setuid(geteuid()) < 0)
143			_exit(1);
144		if (strcmp(gargv[0], _PATH_LS) == 0) {
145			/* Reset getopt for ls_main() */
146			optreset = optind = optopt = 1;
147			/* Close syslogging to remove pwd.db missing msgs */
148			closelog();
149			/* Trigger to sense new /etc/localtime after chroot */
150			if (getenv("TZ") == NULL) {
151				setenv("TZ", "", 0);
152				tzset();
153				unsetenv("TZ");
154				tzset();
155			}
156			exit(ls_main(gargc, gargv));
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, omask, status;
181	pid_t pid;
182
183	/*
184	 * pclose returns -1 if stream is not associated with a
185	 * `popened' command, or, if already `pclosed'.
186	 */
187	if (pids == NULL || pids[fdes = fileno(iop)] == 0)
188		return (-1);
189	(void)fclose(iop);
190	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
191	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
192		continue;
193	(void)sigsetmask(omask);
194	pids[fdes] = 0;
195	if (pid < 0)
196		return (pid);
197	if (WIFEXITED(status))
198		return (WEXITSTATUS(status));
199	return (1);
200}
201