/src/net-snmp/agent/netsnmp_close_fds.c
Line | Count | Source |
1 | | #include <net-snmp/net-snmp-config.h> |
2 | | |
3 | | #include <stdio.h> |
4 | | #ifdef HAVE_DIRENT_H |
5 | | #include <dirent.h> |
6 | | #endif |
7 | | #ifdef HAVE_LIMITS_H |
8 | | #include <limits.h> |
9 | | #endif |
10 | | #ifdef HAVE_UNISTD_H |
11 | | #include <unistd.h> |
12 | | #endif |
13 | | |
14 | | #include <net-snmp/agent/netsnmp_close_fds.h> |
15 | | |
16 | | /** |
17 | | * Close all file descriptors larger than @fd. |
18 | | */ |
19 | | void netsnmp_close_fds(int fd) |
20 | 0 | { |
21 | 0 | #if defined(HAVE_FORK) |
22 | 0 | DIR *dir NETSNMP_ATTRIBUTE_UNUSED; |
23 | 0 | struct dirent *ent NETSNMP_ATTRIBUTE_UNUSED; |
24 | 0 | int i, largest_fd = -1; |
25 | |
|
26 | 0 | if (fd < -1) |
27 | 0 | fd = -1; |
28 | |
|
29 | 0 | #ifdef __linux__ |
30 | | #ifdef __NR_close_range |
31 | | if (syscall(__NR_close_range, fd + 1, UINT_MAX, 0) == 0) |
32 | | return; |
33 | | #endif |
34 | |
|
35 | 0 | if ((dir = opendir("/proc/self/fd"))) { |
36 | 0 | while ((ent = readdir(dir))) { |
37 | 0 | if (sscanf(ent->d_name, "%d", &i) == 1) { |
38 | 0 | if (i > largest_fd) |
39 | 0 | largest_fd = i; |
40 | 0 | } |
41 | 0 | } |
42 | 0 | closedir(dir); |
43 | 0 | } |
44 | | #elif defined(__FreeBSD__) || defined(__OpenBSD__) |
45 | | if ((dir = opendir("/dev/fd"))) { |
46 | | while ((ent = readdir(dir))) { |
47 | | if (sscanf(ent->d_name, "%d", &i) == 1) { |
48 | | if (i > largest_fd) |
49 | | largest_fd = i; |
50 | | } |
51 | | } |
52 | | closedir(dir); |
53 | | } |
54 | | #endif |
55 | 0 | if (largest_fd < 0) { |
56 | 0 | #ifdef HAVE_GETDTABLESIZE |
57 | 0 | largest_fd = getdtablesize() - 1; |
58 | | #else |
59 | | largest_fd = sysconf(_SC_OPEN_MAX); |
60 | | #endif |
61 | 0 | } |
62 | |
|
63 | 0 | for (i = largest_fd; i > fd && i >= 0; i--) |
64 | 0 | close(i); |
65 | 0 | #endif /* defined(HAVE_FORK) */ |
66 | 0 | } |