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
35 static 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 noone
64 * may create a pipe to a hidden program as a side effect of a list or dir
65 * command.
66 */
67 static int *pids;
68 static int fds;
69
70 FILE *
ftpd_popen(char * program,char * type)71 ftpd_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 = malloc(fds * sizeof(int))) == NULL)
85 return (NULL);
86 memset(pids, 0, fds * sizeof(int));
87 }
88 if (pipe(pdes) < 0)
89 return (NULL);
90
91 /* break up string into pieces */
92 for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) {
93 if (!(argv[argc++] = strtok(cp, " \t\n")))
94 break;
95 }
96 argv[argc - 1] = NULL;
97
98 /* glob each piece */
99 gargv[0] = argv[0];
100 for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) {
101 glob_t gl;
102 int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE;
103
104 memset(&gl, 0, sizeof(gl));
105 gl.gl_matchc = MAXGLOBARGS;
106 flags |= GLOB_LIMIT;
107 if (glob(argv[argc], flags, NULL, &gl))
108 gargv[gargc++] = strdup(argv[argc]);
109 else if (gl.gl_pathc > 0) {
110 for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1);
111 pop++)
112 gargv[gargc++] = strdup(*pop);
113 }
114 globfree(&gl);
115 }
116 gargv[gargc] = NULL;
117
118 iop = NULL;
119 fflush(NULL);
120 pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork();
121 switch(pid) {
122 case -1: /* error */
123 (void)close(pdes[0]);
124 (void)close(pdes[1]);
125 goto pfree;
126 /* NOTREACHED */
127 case 0: /* child */
128 if (*type == 'r') {
129 if (pdes[1] != STDOUT_FILENO) {
130 dup2(pdes[1], STDOUT_FILENO);
131 (void)close(pdes[1]);
132 }
133 dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
134 (void)close(pdes[0]);
135 } else {
136 if (pdes[0] != STDIN_FILENO) {
137 dup2(pdes[0], STDIN_FILENO);
138 (void)close(pdes[0]);
139 }
140 (void)close(pdes[1]);
141 }
142 /* Drop privileges before proceeding */
143 if (getuid() != geteuid() && setuid(geteuid()) < 0)
144 _exit(1);
145 if (strcmp(gargv[0], _PATH_LS) == 0) {
146 /* Reset getopt for ls_main() */
147 optreset = optind = optopt = 1;
148 /* Close syslogging to remove pwd.db missing msgs */
149 closelog();
150 /* Trigger to sense new /etc/localtime after chroot */
151 if (getenv("TZ") == NULL) {
152 setenv("TZ", "", 0);
153 tzset();
154 unsetenv("TZ");
155 tzset();
156 }
157 exit(ls_main(gargc, gargv));
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
172 pfree: for (argc = 1; gargv[argc] != NULL; argc++)
173 free(gargv[argc]);
174
175 return (iop);
176 }
177
178 int
ftpd_pclose(FILE * iop)179 ftpd_pclose(FILE *iop)
180 {
181 int fdes, omask, status;
182 pid_t pid;
183
184 /*
185 * pclose returns -1 if stream is not associated with a
186 * `popened' command, or, if already `pclosed'.
187 */
188 if (pids == 0 || pids[fdes = fileno(iop)] == 0)
189 return (-1);
190 (void)fclose(iop);
191 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
192 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
193 continue;
194 (void)sigsetmask(omask);
195 pids[fdes] = 0;
196 if (pid < 0)
197 return (pid);
198 if (WIFEXITED(status))
199 return (WEXITSTATUS(status));
200 return (1);
201 }
202