1 | /* shm_open -- open a POSIX shared memory object. Generic POSIX file version. |
2 | Copyright (C) 2001-2017 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 | |
44 | /* Disable asynchronous cancellation. */ |
45 | int state; |
46 | pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); |
47 | |
48 | int fd = open (shm_name, oflag, mode); |
49 | if (fd == -1 && __glibc_unlikely (errno == EISDIR)) |
50 | /* It might be better to fold this error with EINVAL since |
51 | directory names are just another example for unsuitable shared |
52 | object names and the standard does not mention EISDIR. */ |
53 | __set_errno (EINVAL); |
54 | |
55 | # ifndef O_CLOEXEC |
56 | if (fd != -1) |
57 | { |
58 | /* We got a descriptor. Now set the FD_CLOEXEC bit. */ |
59 | int flags = fcntl (fd, F_GETFD, 0); |
60 | |
61 | if (__glibc_likely (flags != -1)) |
62 | { |
63 | flags |= FD_CLOEXEC; |
64 | flags = fcntl (fd, F_SETFD, flags); |
65 | } |
66 | |
67 | if (flags == -1) |
68 | { |
69 | /* Something went wrong. We cannot return the descriptor. */ |
70 | int save_errno = errno; |
71 | close (fd); |
72 | fd = -1; |
73 | __set_errno (save_errno); |
74 | } |
75 | } |
76 | # endif |
77 | |
78 | pthread_setcancelstate (state, NULL); |
79 | |
80 | return fd; |
81 | } |
82 | |
83 | #endif /* _POSIX_MAPPED_FILES */ |
84 | |