1 /*
2 * Copyright (c) 2004-2005, 2007, 2010, 2012-2014
3 * Todd C. Miller <Todd.Miller@courtesan.com>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 // #include <config.h>
19
20 #include <sys/types.h>
21 #include <unistd.h>
22 #include <stdio.h>
23 #ifdef STDC_HEADERS
24 # include <stdlib.h>
25 # include <stddef.h>
26 #else
27 # ifdef HAVE_STDLIB_H
28 # include <stdlib.h>
29 # endif
30 #endif /* STDC_HEADERS */
31 #include <fcntl.h>
32 #include <limits.h>
33 #ifdef HAVE_PSTAT_GETPROC
34 # include <sys/param.h>
35 # include <sys/pstat.h>
36 #else
37 # ifdef HAVE_DIRENT_H
38 # include <dirent.h>
39 # define NAMLEN(dirent) strlen((dirent)->d_name)
40 # else
41 # define dirent direct
42 # define NAMLEN(dirent) (dirent)->d_namlen
43 # ifdef HAVE_SYS_NDIR_H
44 # include <sys/ndir.h>
45 # endif
46 # ifdef HAVE_SYS_DIR_H
47 # include <sys/dir.h>
48 # endif
49 # ifdef HAVE_NDIR_H
50 # include <ndir.h>
51 # endif
52 # endif
53 #endif
54
55 #ifndef OPEN_MAX
56 # define OPEN_MAX 256
57 #endif
58
59 #if defined(HAVE_FCNTL_CLOSEM) && !defined(HAVE_DIRFD)
60 # define closefrom closefrom_fallback
61 #endif
62
63 static inline void
closefrom_close(int fd)64 closefrom_close(int fd)
65 {
66 #ifdef __APPLE__
67 /* Avoid potential libdispatch crash when we close its fds. */
68 (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
69 #else
70 (void)close(fd);
71 #endif
72 }
73
74 /*
75 * Close all file descriptors greater than or equal to lowfd.
76 * This is the expensive (fallback) method.
77 */
78 void
closefrom_fallback(int lowfd)79 closefrom_fallback(int lowfd)
80 {
81 long fd, maxfd;
82
83 /*
84 * Fall back on sysconf() or getdtablesize(). We avoid checking
85 * resource limits since it is possible to open a file descriptor
86 * and then drop the rlimit such that it is below the open fd.
87 */
88 #ifdef HAVE_SYSCONF
89 maxfd = sysconf(_SC_OPEN_MAX);
90 #else
91 maxfd = getdtablesize();
92 #endif /* HAVE_SYSCONF */
93 if (maxfd < 0)
94 maxfd = OPEN_MAX;
95
96 for (fd = lowfd; fd < maxfd; fd++)
97 closefrom_close(fd);
98 }
99
100 /*
101 * Close all file descriptors greater than or equal to lowfd.
102 * We try the fast way first, falling back on the slow method.
103 */
104 #if defined(HAVE_FCNTL_CLOSEM)
105 void
closefrom(int lowfd)106 closefrom(int lowfd)
107 {
108 if (fcntl(lowfd, F_CLOSEM, 0) == -1)
109 closefrom_fallback(lowfd);
110 }
111 #elif defined(HAVE_PSTAT_GETPROC)
112 void
closefrom(int lowfd)113 closefrom(int lowfd)
114 {
115 struct pst_status pstat;
116 int fd;
117
118 if (pstat_getproc(&pstat, sizeof(pstat), 0, getpid()) != -1) {
119 for (fd = lowfd; fd <= pstat.pst_highestfd; fd++)
120 (void)close(fd);
121 } else {
122 closefrom_fallback(lowfd);
123 }
124 }
125 #elif defined(HAVE_DIRFD)
126 static int
closefrom_procfs(int lowfd)127 closefrom_procfs(int lowfd)
128 {
129 const char *path;
130 DIR *dirp;
131 struct dirent *dent;
132 int *fd_array = NULL;
133 int fd_array_used = 0;
134 int fd_array_size = 0;
135 int ret = 0;
136 int i;
137
138 /* Use /proc/self/fd (or /dev/fd on FreeBSD) if it exists. */
139 # if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__APPLE__)
140 path = "/dev/fd";
141 # else
142 path = "/proc/self/fd";
143 # endif
144 dirp = opendir(path);
145 if (dirp == NULL)
146 return -1;
147
148 while ((dent = readdir(dirp)) != NULL) {
149 const char *errstr;
150 int fd;
151
152 fd = strtonum(dent->d_name, lowfd, INT_MAX, &errstr);
153 if (errstr != NULL || fd == dirfd(dirp))
154 continue;
155
156 if (fd_array_used >= fd_array_size) {
157 int *ptr;
158
159 if (fd_array_size > 0)
160 fd_array_size *= 2;
161 else
162 fd_array_size = 32;
163
164 ptr = reallocarray(fd_array, fd_array_size, sizeof(int));
165 if (ptr == NULL) {
166 ret = -1;
167 break;
168 }
169 fd_array = ptr;
170 }
171
172 fd_array[fd_array_used++] = fd;
173 }
174
175 for (i = 0; i < fd_array_used; i++)
176 closefrom_close(fd_array[i]);
177
178 free(fd_array);
179 (void)closedir(dirp);
180
181 return ret;
182 }
183
184 void
closefrom(int lowfd)185 closefrom(int lowfd)
186 {
187 if (closefrom_procfs(lowfd) == 0)
188 return;
189
190 closefrom_fallback(lowfd);
191 }
192 #endif /* HAVE_FCNTL_CLOSEM */
193