Commit | Line | Data |
---|---|---|
7d4ab47d MJ |
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> | |
e9466c8f | 8 | * 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
7d4ab47d MJ |
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 | ||
7d4ab47d MJ |
29 | /* |
30 | * This wrapper is used on platforms that have no way of ignoring SIGPIPE | |
e9466c8f | 31 | * during a send(). |
7d4ab47d MJ |
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 | |
e9466c8f MD |
47 | |
48 | #include <signal.h> | |
49 | ||
7d4ab47d MJ |
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; | |
e9466c8f MD |
55 | sigset_t sigpipe_set, pending_set, old_set; |
56 | int sigpipe_was_pending; | |
7d4ab47d | 57 | |
e9466c8f MD |
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 | } | |
7d4ab47d MJ |
90 | } |
91 | ||
e9466c8f | 92 | /* Send and save errno. */ |
7d4ab47d MJ |
93 | sent = send(fd, buffer, size, 0); |
94 | saved_err = errno; | |
95 | ||
e9466c8f MD |
96 | if (sent == -1 && errno == EPIPE && !sigpipe_was_pending) { |
97 | struct timespec timeout = { 0, 0 }; | |
98 | int ret; | |
7d4ab47d | 99 | |
e9466c8f MD |
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 | } | |
7d4ab47d MJ |
110 | /* Restore send() errno */ |
111 | errno = saved_err; | |
1fedc0e8 | 112 | |
7d4ab47d MJ |
113 | return sent; |
114 | } | |
115 | #endif | |
116 | ||
117 | #endif /* _BABELTRACE_COMPAT_SEND_H */ |