1 | /* shm_open -- open a POSIX shared memory object. Generic POSIX file version. |
2 | Copyright (C) 2001-2016 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <unistd.h> |
20 | |
21 | #if ! _POSIX_MAPPED_FILES |
22 | |
23 | # include <rt/shm_open.c> |
24 | |
25 | #else |
26 | |
27 | # include <fcntl.h> |
28 | # include <shm-directory.h> |
29 | |
30 | |
31 | /* Open shared memory object. */ |
32 | int |
33 | shm_open (const char *name, int oflag, mode_t mode) |
34 | { |
35 | SHM_GET_NAME (EINVAL, -1, "" ); |
36 | |
37 | # ifdef O_NOFOLLOW |
38 | oflag |= O_NOFOLLOW; |
39 | # endif |
40 | # ifdef O_CLOEXEC |
41 | oflag |= O_CLOEXEC; |
42 | # endif |
43 | int fd = open (shm_name, oflag, mode); |
44 | if (fd == -1 && __glibc_unlikely (errno == EISDIR)) |
45 | /* It might be better to fold this error with EINVAL since |
46 | directory names are just another example for unsuitable shared |
47 | object names and the standard does not mention EISDIR. */ |
48 | __set_errno (EINVAL); |
49 | |
50 | # ifndef O_CLOEXEC |
51 | if (fd != -1) |
52 | { |
53 | /* We got a descriptor. Now set the FD_CLOEXEC bit. */ |
54 | int flags = fcntl (fd, F_GETFD, 0); |
55 | |
56 | if (__glibc_likely (flags != -1)) |
57 | { |
58 | flags |= FD_CLOEXEC; |
59 | flags = fcntl (fd, F_SETFD, flags); |
60 | } |
61 | |
62 | if (flags == -1) |
63 | { |
64 | /* Something went wrong. We cannot return the descriptor. */ |
65 | int save_errno = errno; |
66 | close (fd); |
67 | fd = -1; |
68 | __set_errno (save_errno); |
69 | } |
70 | } |
71 | # endif |
72 | |
73 | return fd; |
74 | } |
75 | |
76 | #endif /* _POSIX_MAPPED_FILES */ |
77 | |