Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-6.2-pull-reques...
[qemu.git] / util / compatfd.c
1 /*
2 * signalfd/eventfd compatibility
3 *
4 * Copyright IBM, Corp. 2008
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
14 */
15
16 #include "qemu/osdep.h"
17 #include "qemu/thread.h"
18
19 #if defined(CONFIG_SIGNALFD)
20 #include <sys/syscall.h>
21 #endif
22
23 struct sigfd_compat_info {
24 sigset_t mask;
25 int fd;
26 };
27
28 static void *sigwait_compat(void *opaque)
29 {
30 struct sigfd_compat_info *info = opaque;
31
32 while (1) {
33 int sig;
34 int err;
35
36 err = sigwait(&info->mask, &sig);
37 if (err != 0) {
38 if (errno == EINTR) {
39 continue;
40 } else {
41 return NULL;
42 }
43 } else {
44 struct qemu_signalfd_siginfo buffer;
45 size_t offset = 0;
46
47 memset(&buffer, 0, sizeof(buffer));
48 buffer.ssi_signo = sig;
49
50 while (offset < sizeof(buffer)) {
51 ssize_t len;
52
53 len = write(info->fd, (char *)&buffer + offset,
54 sizeof(buffer) - offset);
55 if (len == -1 && errno == EINTR) {
56 continue;
57 }
58
59 if (len <= 0) {
60 return NULL;
61 }
62
63 offset += len;
64 }
65 }
66 }
67 }
68
69 static int qemu_signalfd_compat(const sigset_t *mask)
70 {
71 struct sigfd_compat_info *info;
72 QemuThread thread;
73 int fds[2];
74
75 info = g_malloc(sizeof(*info));
76
77 if (pipe(fds) == -1) {
78 g_free(info);
79 return -1;
80 }
81
82 qemu_set_cloexec(fds[0]);
83 qemu_set_cloexec(fds[1]);
84
85 memcpy(&info->mask, mask, sizeof(*mask));
86 info->fd = fds[1];
87
88 qemu_thread_create(&thread, "signalfd_compat", sigwait_compat, info,
89 QEMU_THREAD_DETACHED);
90
91 return fds[0];
92 }
93
94 int qemu_signalfd(const sigset_t *mask)
95 {
96 #if defined(CONFIG_SIGNALFD)
97 int ret;
98
99 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
100 if (ret != -1) {
101 qemu_set_cloexec(ret);
102 return ret;
103 }
104 #endif
105
106 return qemu_signalfd_compat(mask);
107 }