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c65eb836 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2013 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <pthread.h> | |
23 | #include <unistd.h> | |
24 | ||
f485606b | 25 | #include "async.h" |
3ffd4af2 | 26 | #include "fd-util.h" |
f485606b | 27 | #include "log.h" |
8a474b0c | 28 | #include "util.h" |
c65eb836 | 29 | |
f485606b | 30 | int asynchronous_job(void* (*func)(void *p), void *arg) { |
c65eb836 LP |
31 | pthread_attr_t a; |
32 | pthread_t t; | |
33 | int r; | |
34 | ||
35 | /* It kinda sucks that we have to resort to threads to | |
36 | * implement an asynchronous sync(), but well, such is | |
37 | * life. | |
38 | * | |
39 | * Note that issuing this command right before exiting a | |
40 | * process will cause the process to wait for the sync() to | |
41 | * complete. This function hence is nicely asynchronous really | |
42 | * only in long running processes. */ | |
43 | ||
44 | r = pthread_attr_init(&a); | |
c1d630d5 | 45 | if (r > 0) |
c65eb836 LP |
46 | return -r; |
47 | ||
48 | r = pthread_attr_setdetachstate(&a, PTHREAD_CREATE_DETACHED); | |
c1d630d5 | 49 | if (r > 0) |
c65eb836 | 50 | goto finish; |
c65eb836 | 51 | |
f485606b | 52 | r = pthread_create(&t, &a, func, arg); |
c65eb836 LP |
53 | |
54 | finish: | |
55 | pthread_attr_destroy(&a); | |
c1d630d5 | 56 | return -r; |
c65eb836 | 57 | } |
f485606b ZJS |
58 | |
59 | static void *sync_thread(void *p) { | |
60 | sync(); | |
61 | return NULL; | |
62 | } | |
63 | ||
64 | int asynchronous_sync(void) { | |
65 | log_debug("Spawning new thread for sync"); | |
66 | ||
67 | return asynchronous_job(sync_thread, NULL); | |
68 | } | |
8a474b0c LP |
69 | |
70 | static void *close_thread(void *p) { | |
5ed12272 | 71 | assert_se(close_nointr(PTR_TO_INT(p)) != -EBADF); |
8a474b0c LP |
72 | return NULL; |
73 | } | |
74 | ||
75 | int asynchronous_close(int fd) { | |
76 | int r; | |
77 | ||
78 | /* This is supposed to behave similar to safe_close(), but | |
79 | * actually invoke close() asynchronously, so that it will | |
80 | * never block. Ideally the kernel would have an API for this, | |
81 | * but it doesn't, so we work around it, and hide this as a | |
82 | * far away as we can. */ | |
83 | ||
5ed12272 LP |
84 | if (fd >= 0) { |
85 | PROTECT_ERRNO; | |
86 | ||
87 | r = asynchronous_job(close_thread, INT_TO_PTR(fd)); | |
88 | if (r < 0) | |
89 | assert_se(close_nointr(fd) != -EBADF); | |
90 | } | |
8a474b0c LP |
91 | |
92 | return -1; | |
93 | } |