| xf.li | bfc6e71 | 2025-02-07 01:54:34 -0800 | [diff] [blame^] | 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 */ |