1 /*
2 * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17 #include "includes.h"
18
19 #ifndef HAVE_CLOSEFROM
20
21 #include <sys/types.h>
22 #include <sys/param.h>
23 #include <unistd.h>
24 #include <stdio.h>
25 #ifdef HAVE_FCNTL_H
26 # include <fcntl.h>
27 #endif
28 #include <limits.h>
29 #include <stdlib.h>
30 #include <stddef.h>
31 #include <string.h>
32 #include <unistd.h>
33 #ifdef HAVE_DIRENT_H
34 # include <dirent.h>
35 # define NAMLEN(dirent) strlen((dirent)->d_name)
36 #else
37 # define dirent direct
38 # define NAMLEN(dirent) (dirent)->d_namlen
39 # ifdef HAVE_SYS_NDIR_H
40 # include <sys/ndir.h>
41 # endif
42 # ifdef HAVE_SYS_DIR_H
43 # include <sys/dir.h>
44 # endif
45 # ifdef HAVE_NDIR_H
46 # include <ndir.h>
47 # endif
48 #endif
49 #if defined(HAVE_LIBPROC_H)
50 # include <libproc.h>
51 #endif
52
53 #ifndef OPEN_MAX
54 # define OPEN_MAX 256
55 #endif
56
57 #if 0
58 __unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
59 #endif /* lint */
60
61 #ifndef HAVE_FCNTL_CLOSEM
62 /*
63 * Close all file descriptors greater than or equal to lowfd.
64 */
65 static void
closefrom_fallback(int lowfd)66 closefrom_fallback(int lowfd)
67 {
68 long fd, maxfd;
69
70 /*
71 * Fall back on sysconf() or getdtablesize(). We avoid checking
72 * resource limits since it is possible to open a file descriptor
73 * and then drop the rlimit such that it is below the open fd.
74 */
75 #ifdef HAVE_SYSCONF
76 maxfd = sysconf(_SC_OPEN_MAX);
77 #else
78 maxfd = getdtablesize();
79 #endif /* HAVE_SYSCONF */
80 if (maxfd < 0)
81 maxfd = OPEN_MAX;
82
83 for (fd = lowfd; fd < maxfd; fd++)
84 (void) close((int) fd);
85 }
86 #endif /* HAVE_FCNTL_CLOSEM */
87
88 #ifdef HAVE_FCNTL_CLOSEM
89 void
closefrom(int lowfd)90 closefrom(int lowfd)
91 {
92 (void) fcntl(lowfd, F_CLOSEM, 0);
93 }
94 #elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)
95 void
closefrom(int lowfd)96 closefrom(int lowfd)
97 {
98 int i, r, sz;
99 pid_t pid = getpid();
100 struct proc_fdinfo *fdinfo_buf = NULL;
101
102 sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
103 if (sz == 0)
104 return; /* no fds, really? */
105 else if (sz == -1)
106 goto fallback;
107 if ((fdinfo_buf = malloc(sz)) == NULL)
108 goto fallback;
109 r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);
110 if (r < 0 || r > sz)
111 goto fallback;
112 for (i = 0; i < r / (int)PROC_PIDLISTFD_SIZE; i++) {
113 if (fdinfo_buf[i].proc_fd >= lowfd)
114 close(fdinfo_buf[i].proc_fd);
115 }
116 free(fdinfo_buf);
117 return;
118 fallback:
119 free(fdinfo_buf);
120 closefrom_fallback(lowfd);
121 return;
122 }
123 #elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
124 void
closefrom(int lowfd)125 closefrom(int lowfd)
126 {
127 long fd;
128 char fdpath[PATH_MAX], *endp;
129 struct dirent *dent;
130 DIR *dirp;
131 int len;
132
133 /* Check for a /proc/$$/fd directory. */
134 len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
135 if (len > 0 && (size_t)len < sizeof(fdpath) && (dirp = opendir(fdpath))) {
136 while ((dent = readdir(dirp)) != NULL) {
137 fd = strtol(dent->d_name, &endp, 10);
138 if (dent->d_name != endp && *endp == '\0' &&
139 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
140 (void) close((int) fd);
141 }
142 (void) closedir(dirp);
143 return;
144 }
145 /* /proc/$$/fd strategy failed, fall back to brute force closure */
146 closefrom_fallback(lowfd);
147 }
148 #else
149 void
closefrom(int lowfd)150 closefrom(int lowfd)
151 {
152 closefrom_fallback(lowfd);
153 }
154 #endif /* !HAVE_FCNTL_CLOSEM */
155 #endif /* HAVE_CLOSEFROM */
156