xref: /dragonfly/libexec/ftpd/popen.c (revision 3170ffd7)
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  * 4. 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  * @(#)popen.c	8.3 (Berkeley) 4/6/94
33  * $FreeBSD: src/libexec/ftpd/popen.c,v 1.26 2004/11/18 13:46:29 yar Exp $
34  */
35 
36 #include <sys/types.h>
37 #include <sys/wait.h>
38 #include <netinet/in.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 <unistd.h>
47 
48 #include "extern.h"
49 #include "pathnames.h"
50 #include <syslog.h>
51 #include <time.h>
52 
53 #define	MAXUSRARGS	100
54 #define	MAXGLOBARGS	1000
55 
56 /*
57  * Special version of popen which avoids call to shell.  This ensures noone
58  * may create a pipe to a hidden program as a side effect of a list or dir
59  * command.
60  */
61 static int *pids;
62 static int fds;
63 
64 FILE *
65 ftpd_popen(char *program, char *type)
66 {
67 	char *cp;
68 	FILE *iop;
69 	int argc, gargc, pdes[2], pid;
70 	char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS];
71 
72 	if (((*type != 'r') && (*type != 'w')) || type[1])
73 		return (NULL);
74 
75 	if (!pids) {
76 		if ((fds = getdtablesize()) <= 0)
77 			return (NULL);
78 		if ((pids = malloc(fds * sizeof(int))) == NULL)
79 			return (NULL);
80 		memset(pids, 0, fds * sizeof(int));
81 	}
82 	if (pipe(pdes) < 0)
83 		return (NULL);
84 
85 	/* break up string into pieces */
86 	for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) {
87 		if (!(argv[argc++] = strtok(cp, " \t\n")))
88 			break;
89 	}
90 	argv[argc - 1] = NULL;
91 
92 	/* glob each piece */
93 	gargv[0] = argv[0];
94 	for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) {
95 		glob_t gl;
96 		int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE;
97 
98 		memset(&gl, 0, sizeof(gl));
99 		gl.gl_matchc = MAXGLOBARGS;
100 		/*flags |= GLOB_LIMIT;*/
101 		if (glob(argv[argc], flags, NULL, &gl))
102 			gargv[gargc++] = strdup(argv[argc]);
103 		else
104 			for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1);
105 			     pop++)
106 				gargv[gargc++] = strdup(*pop);
107 		globfree(&gl);
108 	}
109 	gargv[gargc] = NULL;
110 
111 	iop = NULL;
112 	fflush(NULL);
113 	pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork();
114 	switch(pid) {
115 	case -1:			/* error */
116 		close(pdes[0]);
117 		close(pdes[1]);
118 		goto pfree;
119 		/* NOTREACHED */
120 	case 0:				/* child */
121 		if (*type == 'r') {
122 			if (pdes[1] != STDOUT_FILENO) {
123 				dup2(pdes[1], STDOUT_FILENO);
124 				close(pdes[1]);
125 			}
126 			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
127 			close(pdes[0]);
128 		} else {
129 			if (pdes[0] != STDIN_FILENO) {
130 				dup2(pdes[0], STDIN_FILENO);
131 				close(pdes[0]);
132 			}
133 			close(pdes[1]);
134 		}
135 		if (strcmp(gargv[0], _PATH_LS) == 0) {
136 			/* Reset getopt for ls_main() */
137 			optreset = optind = optopt = 1;
138 			/* Close syslogging to remove pwd.db missing msgs */
139 			closelog();
140 			/* Trigger to sense new /etc/localtime after chroot */
141 			if (getenv("TZ") == NULL) {
142 				if (setenv("TZ", "", 0) == -1)
143 					syslog(LOG_ERR, "setenv: cannot set TZ: %m");
144 				tzset();
145 				unsetenv("TZ");
146 				tzset();
147 			}
148 			exit(ls_main(gargc, gargv));
149 		}
150 		execv(gargv[0], gargv);
151 		_exit(1);
152 	}
153 	/* parent; assume fdopen can't fail...  */
154 	if (*type == 'r') {
155 		iop = fdopen(pdes[0], type);
156 		close(pdes[1]);
157 	} else {
158 		iop = fdopen(pdes[1], type);
159 		close(pdes[0]);
160 	}
161 	pids[fileno(iop)] = pid;
162 
163 pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
164 		free(gargv[argc]);
165 
166 	return (iop);
167 }
168 
169 int
170 ftpd_pclose(FILE *iop)
171 {
172 	int fdes, omask, status;
173 	pid_t pid;
174 
175 	/*
176 	 * pclose returns -1 if stream is not associated with a
177 	 * `popened' command, or, if already `pclosed'.
178 	 */
179 	if (pids == NULL || pids[fdes = fileno(iop)] == 0)
180 		return (-1);
181 	fclose(iop);
182 	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
183 	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
184 		continue;
185 	sigsetmask(omask);
186 	pids[fdes] = 0;
187 	if (pid < 0)
188 		return (pid);
189 	if (WIFEXITED(status))
190 		return (WEXITSTATUS(status));
191 	return (1);
192 }
193