| 1 | #ifndef _BABELTRACE_COMPAT_SEND_H |
| 2 | #define _BABELTRACE_COMPAT_SEND_H |
| 3 | |
| 4 | /* |
| 5 | * babeltrace/compat/send.h |
| 6 | * |
| 7 | * Copyright (C) 2015 Michael Jeanson <mjeanson@efficios.com> |
| 8 | * 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 9 | * |
| 10 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 11 | * of this software and associated documentation files (the "Software"), to deal |
| 12 | * in the Software without restriction, including without limitation the rights |
| 13 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 14 | * copies of the Software, and to permit persons to whom the Software is |
| 15 | * furnished to do so, subject to the following conditions: |
| 16 | * |
| 17 | * The above copyright notice and this permission notice shall be included in |
| 18 | * all copies or substantial portions of the Software. |
| 19 | * |
| 20 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 21 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 22 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 23 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 24 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 25 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 26 | * SOFTWARE. |
| 27 | */ |
| 28 | |
| 29 | /* |
| 30 | * This wrapper is used on platforms that have no way of ignoring SIGPIPE |
| 31 | * during a send(). |
| 32 | */ |
| 33 | |
| 34 | #ifndef MSG_NOSIGNAL |
| 35 | # ifdef SO_NOSIGPIPE |
| 36 | # define MSG_NOSIGNAL SO_NOSIGPIPE |
| 37 | # endif |
| 38 | #endif |
| 39 | |
| 40 | #if defined(MSG_NOSIGNAL) |
| 41 | static inline |
| 42 | ssize_t bt_send_nosigpipe(int fd, const void *buffer, size_t size) |
| 43 | { |
| 44 | return send(fd, buffer, size, MSG_NOSIGNAL); |
| 45 | } |
| 46 | #else |
| 47 | |
| 48 | #include <signal.h> |
| 49 | |
| 50 | static inline |
| 51 | ssize_t bt_send_nosigpipe(int fd, const void *buffer, size_t size) |
| 52 | { |
| 53 | ssize_t sent; |
| 54 | int saved_err; |
| 55 | sigset_t sigpipe_set, pending_set, old_set; |
| 56 | int sigpipe_was_pending; |
| 57 | |
| 58 | /* |
| 59 | * Discard the SIGPIPE from send(), not disturbing any SIGPIPE |
| 60 | * that might be already pending. If a bogus SIGPIPE is sent to |
| 61 | * the entire process concurrently by a malicious user, it may |
| 62 | * be simply discarded. |
| 63 | */ |
| 64 | if (sigemptyset(&pending_set)) { |
| 65 | return -1; |
| 66 | } |
| 67 | /* |
| 68 | * sigpending returns the mask of signals that are _both_ |
| 69 | * blocked for the thread _and_ pending for either the thread or |
| 70 | * the entire process. |
| 71 | */ |
| 72 | if (sigpending(&pending_set)) { |
| 73 | return -1; |
| 74 | } |
| 75 | sigpipe_was_pending = sigismember(&pending_set, SIGPIPE); |
| 76 | /* |
| 77 | * If sigpipe was pending, it means it was already blocked, so |
| 78 | * no need to block it. |
| 79 | */ |
| 80 | if (!sigpipe_was_pending) { |
| 81 | if (sigemptyset(&sigpipe_set)) { |
| 82 | return -1; |
| 83 | } |
| 84 | if (sigaddset(&sigpipe_set, SIGPIPE)) { |
| 85 | return -1; |
| 86 | } |
| 87 | if (pthread_sigmask(SIG_BLOCK, &sigpipe_set, &old_set)) { |
| 88 | return -1; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | /* Send and save errno. */ |
| 93 | sent = send(fd, buffer, size, 0); |
| 94 | saved_err = errno; |
| 95 | |
| 96 | if (sent == -1 && errno == EPIPE && !sigpipe_was_pending) { |
| 97 | struct timespec timeout = { 0, 0 }; |
| 98 | int ret; |
| 99 | |
| 100 | do { |
| 101 | ret = sigtimedwait(&sigpipe_set, NULL, |
| 102 | &timeout); |
| 103 | } while (ret == -1 && errno == EINTR); |
| 104 | } |
| 105 | if (!sigpipe_was_pending) { |
| 106 | if (pthread_sigmask(SIG_SETMASK, &old_set, NULL)) { |
| 107 | return -1; |
| 108 | } |
| 109 | } |
| 110 | /* Restore send() errno */ |
| 111 | errno = saved_err; |
| 112 | |
| 113 | return sent; |
| 114 | } |
| 115 | #endif |
| 116 | |
| 117 | #endif /* _BABELTRACE_COMPAT_SEND_H */ |