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 #if !defined(HAVE_CLOSEFROM) || defined(BROKEN_CLOSEFROM)
20
21 #include <sys/types.h>
22 #include <unistd.h>
23 #include <stdio.h>
24 #ifdef HAVE_FCNTL_H
25 # include <fcntl.h>
26 #endif
27 #include <limits.h>
28 #include <stdlib.h>
29 #include <stddef.h>
30 #include <string.h>
31 #ifdef HAVE_DIRENT_H
32 # include <dirent.h>
33 # define NAMLEN(dirent) strlen((dirent)->d_name)
34 #else
35 # define dirent direct
36 # define NAMLEN(dirent) (dirent)->d_namlen
37 # ifdef HAVE_SYS_NDIR_H
38 # include <sys/ndir.h>
39 # endif
40 # ifdef HAVE_SYS_DIR_H
41 # include <sys/dir.h>
42 # endif
43 # ifdef HAVE_NDIR_H
44 # include <ndir.h>
45 # endif
46 #endif
47 #if defined(HAVE_LIBPROC_H)
48 # include <libproc.h>
49 #endif
50
51 #ifndef OPEN_MAX
52 # define OPEN_MAX 256
53 #endif
54
55 #if 0
56 __unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
57 #endif /* lint */
58
59 #ifndef HAVE_FCNTL_CLOSEM
60 /*
61 * Close all file descriptors greater than or equal to lowfd.
62 */
63 static void
closefrom_fallback(int lowfd)64 closefrom_fallback(int lowfd)
65 {
66 long fd, maxfd;
67
68 /*
69 * Fall back on sysconf() or getdtablesize(). We avoid checking
70 * resource limits since it is possible to open a file descriptor
71 * and then drop the rlimit such that it is below the open fd.
72 */
73 #ifdef HAVE_SYSCONF
74 maxfd = sysconf(_SC_OPEN_MAX);
75 #else
76 maxfd = getdtablesize();
77 #endif /* HAVE_SYSCONF */
78 if (maxfd < 0)
79 maxfd = OPEN_MAX;
80
81 for (fd = lowfd; fd < maxfd; fd++)
82 (void) close((int) fd);
83 }
84 #endif /* HAVE_FCNTL_CLOSEM */
85
86 #ifdef HAVE_FCNTL_CLOSEM
87 void
closefrom(int lowfd)88 closefrom(int lowfd)
89 {
90 (void) fcntl(lowfd, F_CLOSEM, 0);
91 }
92 #elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)
93 void
closefrom(int lowfd)94 closefrom(int lowfd)
95 {
96 int i, r, sz;
97 pid_t pid = getpid();
98 struct proc_fdinfo *fdinfo_buf = NULL;
99
100 sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
101 if (sz == 0)
102 return; /* no fds, really? */
103 else if (sz == -1)
104 goto fallback;
105 if ((fdinfo_buf = malloc(sz)) == NULL)
106 goto fallback;
107 r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);
108 if (r < 0 || r > sz)
109 goto fallback;
110 for (i = 0; i < r / (int)PROC_PIDLISTFD_SIZE; i++) {
111 if (fdinfo_buf[i].proc_fd >= lowfd)
112 close(fdinfo_buf[i].proc_fd);
113 }
114 free(fdinfo_buf);
115 return;
116 fallback:
117 free(fdinfo_buf);
118 closefrom_fallback(lowfd);
119 return;
120 }
121 #elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
122 void
closefrom(int lowfd)123 closefrom(int lowfd)
124 {
125 long fd;
126 char fdpath[PATH_MAX], *endp;
127 struct dirent *dent;
128 DIR *dirp;
129 int len;
130
131 #ifdef HAVE_CLOSE_RANGE
132 if (close_range(lowfd, INT_MAX, 0) == 0)
133 return;
134 #endif
135
136 /* Check for a /proc/$$/fd directory. */
137 len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
138 if (len > 0 && (size_t)len < sizeof(fdpath) && (dirp = opendir(fdpath))) {
139 while ((dent = readdir(dirp)) != NULL) {
140 fd = strtol(dent->d_name, &endp, 10);
141 if (dent->d_name != endp && *endp == '\0' &&
142 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
143 (void) close((int) fd);
144 }
145 (void) closedir(dirp);
146 return;
147 }
148 /* /proc/$$/fd strategy failed, fall back to brute force closure */
149 closefrom_fallback(lowfd);
150 }
151 #else
152 void
closefrom(int lowfd)153 closefrom(int lowfd)
154 {
155 closefrom_fallback(lowfd);
156 }
157 #endif /* !HAVE_FCNTL_CLOSEM */
158 #endif /* HAVE_CLOSEFROM */
159