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221dc560 | 1 | /* shm_open -- open a POSIX shared memory object. Generic POSIX file version. |
bfff8b1b | 2 | Copyright (C) 2001-2017 Free Software Foundation, Inc. |
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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 | |
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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. | |
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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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
221dc560 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
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16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
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18 | |
19 | #include <unistd.h> | |
20 | ||
21 | #if ! _POSIX_MAPPED_FILES | |
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22 | |
23 | # include <rt/shm_open.c> | |
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24 | |
25 | #else | |
26 | ||
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27 | # include <fcntl.h> |
28 | # include <shm-directory.h> | |
221dc560 | 29 | |
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30 | |
31 | /* Open shared memory object. */ | |
32 | int | |
33 | shm_open (const char *name, int oflag, mode_t mode) | |
34 | { | |
e4f639e4 | 35 | SHM_GET_NAME (EINVAL, -1, ""); |
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36 | |
37 | # ifdef O_NOFOLLOW | |
38 | oflag |= O_NOFOLLOW; | |
39 | # endif | |
40 | # ifdef O_CLOEXEC | |
41 | oflag |= O_CLOEXEC; | |
42 | # endif | |
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43 | |
44 | /* Disable asynchronous cancellation. */ | |
45 | int state; | |
46 | pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); | |
47 | ||
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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 | |
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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 | ||
78e21c5d | 61 | if (__glibc_likely (flags != -1)) |
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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 | } | |
78e21c5d | 76 | # endif |
221dc560 | 77 | |
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78 | pthread_setcancelstate (state, NULL); |
79 | ||
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80 | return fd; |
81 | } | |
82 | ||
78e21c5d | 83 | #endif /* _POSIX_MAPPED_FILES */ |