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Marcelo Tosattidcc38d12010-10-11 15:31:15 -03001/*
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 *
Paolo Bonzini6b620ca2012-01-13 17:44:23 +010012 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030014 */
15
16#include "qemu-common.h"
17#include "compatfd.h"
18
19#include <sys/syscall.h>
20#include <pthread.h>
21
22struct sigfd_compat_info
23{
24 sigset_t mask;
25 int fd;
26};
27
28static void *sigwait_compat(void *opaque)
29{
30 struct sigfd_compat_info *info = opaque;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030031 sigset_t all;
32
33 sigfillset(&all);
Alexander Graf09716e42011-06-09 00:55:37 +020034 pthread_sigmask(SIG_BLOCK, &all, NULL);
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030035
Tristan Gingold30faaf72011-02-18 14:17:16 +010036 while (1) {
37 int sig;
38 int err;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030039
Tristan Gingold30faaf72011-02-18 14:17:16 +010040 err = sigwait(&info->mask, &sig);
41 if (err != 0) {
42 if (errno == EINTR) {
43 continue;
44 } else {
45 return NULL;
46 }
47 } else {
48 struct qemu_signalfd_siginfo buffer;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030049 size_t offset = 0;
50
Tristan Gingold30faaf72011-02-18 14:17:16 +010051 memset(&buffer, 0, sizeof(buffer));
52 buffer.ssi_signo = sig;
53
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030054 while (offset < sizeof(buffer)) {
55 ssize_t len;
56
Tristan Gingold30faaf72011-02-18 14:17:16 +010057 len = write(info->fd, (char *)&buffer + offset,
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030058 sizeof(buffer) - offset);
59 if (len == -1 && errno == EINTR)
60 continue;
61
62 if (len <= 0) {
Tristan Gingold30faaf72011-02-18 14:17:16 +010063 return NULL;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030064 }
65
66 offset += len;
67 }
68 }
Tristan Gingold30faaf72011-02-18 14:17:16 +010069 }
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030070}
71
72static int qemu_signalfd_compat(const sigset_t *mask)
73{
74 pthread_attr_t attr;
75 pthread_t tid;
76 struct sigfd_compat_info *info;
77 int fds[2];
78
79 info = malloc(sizeof(*info));
80 if (info == NULL) {
81 errno = ENOMEM;
82 return -1;
83 }
84
85 if (pipe(fds) == -1) {
86 free(info);
87 return -1;
88 }
89
90 qemu_set_cloexec(fds[0]);
91 qemu_set_cloexec(fds[1]);
92
93 memcpy(&info->mask, mask, sizeof(*mask));
94 info->fd = fds[1];
95
96 pthread_attr_init(&attr);
97 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
98
99 pthread_create(&tid, &attr, sigwait_compat, info);
100
101 pthread_attr_destroy(&attr);
102
103 return fds[0];
104}
105
106int qemu_signalfd(const sigset_t *mask)
107{
108#if defined(CONFIG_SIGNALFD)
109 int ret;
110
111 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
112 if (ret != -1) {
113 qemu_set_cloexec(ret);
114 return ret;
115 }
116#endif
117
118 return qemu_signalfd_compat(mask);
119}
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200120
121bool qemu_signalfd_available(void)
122{
123#ifdef CONFIG_SIGNALFD
Peter Maydell7f84c122011-10-13 18:45:37 +0100124 sigset_t mask;
125 int fd;
126 bool ok;
127 sigemptyset(&mask);
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200128 errno = 0;
Peter Maydell7f84c122011-10-13 18:45:37 +0100129 fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
130 ok = (errno != ENOSYS);
131 if (fd >= 0) {
132 close(fd);
133 }
134 return ok;
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200135#else
136 return false;
137#endif
138}