Annotation of embedaddon/sudo/compat/closefrom.c, revision 1.1.1.1
1.1 misho 1: /*
2: * Copyright (c) 2004-2005, 2007, 2010
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 <sys/param.h>
22: #include <unistd.h>
23: #include <stdio.h>
24: #ifdef STDC_HEADERS
25: # include <stdlib.h>
26: # include <stddef.h>
27: #else
28: # ifdef HAVE_STDLIB_H
29: # include <stdlib.h>
30: # endif
31: #endif /* STDC_HEADERS */
32: #include <fcntl.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:
50: #include "missing.h"
51:
52: #ifndef HAVE_FCNTL_CLOSEM
53: # ifndef HAVE_DIRFD
54: # define closefrom_fallback closefrom
55: # endif
56: #endif
57:
58: /*
59: * Close all file descriptors greater than or equal to lowfd.
60: * This is the expensive (ballback) method.
61: */
62: void
63: closefrom_fallback(int lowfd)
64: {
65: long fd, maxfd;
66:
67: /*
68: * Fall back on sysconf() or getdtablesize(). We avoid checking
69: * resource limits since it is possible to open a file descriptor
70: * and then drop the rlimit such that it is below the open fd.
71: */
72: #ifdef HAVE_SYSCONF
73: maxfd = sysconf(_SC_OPEN_MAX);
74: #else
75: maxfd = getdtablesize();
76: #endif /* HAVE_SYSCONF */
77: if (maxfd < 0)
78: maxfd = OPEN_MAX;
79:
80: for (fd = lowfd; fd < maxfd; fd++)
81: (void) close((int) fd);
82: }
83:
84: /*
85: * Close all file descriptors greater than or equal to lowfd.
86: * We try the fast way first, falling back on the slow method.
87: */
88: #ifdef HAVE_FCNTL_CLOSEM
89: void
90: closefrom(int lowfd)
91: {
92: if (fcntl(lowfd, F_CLOSEM, 0) == -1)
93: closefrom_fallback(lowfd);
94: }
95: #else
96: # ifdef HAVE_DIRFD
97: void
98: closefrom(int lowfd)
99: {
100: struct dirent *dent;
101: DIR *dirp;
102: char *endp;
103: long fd;
104:
105: /* Use /proc/self/fd directory if it exists. */
106: if ((dirp = opendir("/proc/self/fd")) != NULL) {
107: while ((dent = readdir(dirp)) != NULL) {
108: fd = strtol(dent->d_name, &endp, 10);
109: if (dent->d_name != endp && *endp == '\0' &&
110: fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
111: (void) close((int) fd);
112: }
113: (void) closedir(dirp);
114: } else
115: closefrom_fallback(lowfd);
116: }
117: #endif /* HAVE_DIRFD */
118: #endif /* HAVE_FCNTL_CLOSEM */
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