| 1 | /* POSIX compatible signal blocking for threads. |
| 2 | Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| 3 | |
| 4 | This program is free software: you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 3 of the License, or |
| 7 | (at your option) any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | #include <config.h> |
| 18 | |
| 19 | /* Specification. */ |
| 20 | #include <signal.h> |
| 21 | |
| 22 | #include <errno.h> |
| 23 | #include <stddef.h> |
| 24 | |
| 25 | #if PTHREAD_SIGMASK_INEFFECTIVE |
| 26 | # include <string.h> |
| 27 | #endif |
| 28 | |
| 29 | #if PTHREAD_SIGMASK_UNBLOCK_BUG |
| 30 | # include <unistd.h> |
| 31 | #endif |
| 32 | |
| 33 | int |
| 34 | pthread_sigmask (int how, const sigset_t *new_mask, sigset_t *old_mask) |
| 35 | #undef pthread_sigmask |
| 36 | { |
| 37 | #if HAVE_PTHREAD_SIGMASK |
| 38 | int ret; |
| 39 | |
| 40 | # if PTHREAD_SIGMASK_INEFFECTIVE |
| 41 | sigset_t omask, omask_copy; |
| 42 | sigset_t *old_mask_ptr = &omask; |
| 43 | sigemptyset (&omask); |
| 44 | /* Add a signal unlikely to be blocked, so that OMASK_COPY |
| 45 | is unlikely to match the actual mask. */ |
| 46 | sigaddset (&omask, SIGILL); |
| 47 | memcpy (&omask_copy, &omask, sizeof omask); |
| 48 | # else |
| 49 | sigset_t *old_mask_ptr = old_mask; |
| 50 | # endif |
| 51 | |
| 52 | ret = pthread_sigmask (how, new_mask, old_mask_ptr); |
| 53 | |
| 54 | # if PTHREAD_SIGMASK_INEFFECTIVE |
| 55 | if (ret == 0) |
| 56 | { |
| 57 | /* Detect whether pthread_sigmask is currently ineffective. |
| 58 | Don't cache the information: libpthread.so could be dynamically |
| 59 | loaded after the program started and after pthread_sigmask was |
| 60 | called for the first time. */ |
| 61 | if (memcmp (&omask_copy, &omask, sizeof omask) == 0 |
| 62 | && pthread_sigmask (1729, &omask_copy, NULL) == 0) |
| 63 | { |
| 64 | /* pthread_sigmask is currently ineffective. The program is not |
| 65 | linked to -lpthread. So use sigprocmask instead. */ |
| 66 | return (sigprocmask (how, new_mask, old_mask) < 0 ? errno : 0); |
| 67 | } |
| 68 | |
| 69 | if (old_mask) |
| 70 | memcpy (old_mask, &omask, sizeof omask); |
| 71 | } |
| 72 | # endif |
| 73 | # if PTHREAD_SIGMASK_FAILS_WITH_ERRNO |
| 74 | if (ret == -1) |
| 75 | return errno; |
| 76 | # endif |
| 77 | # if PTHREAD_SIGMASK_UNBLOCK_BUG |
| 78 | if (ret == 0 |
| 79 | && new_mask != NULL |
| 80 | && (how == SIG_UNBLOCK || how == SIG_SETMASK)) |
| 81 | { |
| 82 | /* Give the OS the opportunity to raise signals that were pending before |
| 83 | the pthread_sigmask call and have now been unblocked. */ |
| 84 | usleep (1); |
| 85 | } |
| 86 | # endif |
| 87 | return ret; |
| 88 | #else |
| 89 | int ret = sigprocmask (how, new_mask, old_mask); |
| 90 | return (ret < 0 ? errno : 0); |
| 91 | #endif |
| 92 | } |