blob: 02306a4f71ea5b32b88b1468084a621a2012fba0 [file] [log] [blame]
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 *
12 */
13
14#include "qemu-common.h"
15#include "compatfd.h"
16
17#include <sys/syscall.h>
18#include <pthread.h>
19
20struct sigfd_compat_info
21{
22 sigset_t mask;
23 int fd;
24};
25
26static void *sigwait_compat(void *opaque)
27{
28 struct sigfd_compat_info *info = opaque;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030029 sigset_t all;
30
31 sigfillset(&all);
Alexander Graf09716e42011-06-09 00:55:37 +020032 pthread_sigmask(SIG_BLOCK, &all, NULL);
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030033
Tristan Gingold30faaf72011-02-18 14:17:16 +010034 while (1) {
35 int sig;
36 int err;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030037
Tristan Gingold30faaf72011-02-18 14:17:16 +010038 err = sigwait(&info->mask, &sig);
39 if (err != 0) {
40 if (errno == EINTR) {
41 continue;
42 } else {
43 return NULL;
44 }
45 } else {
46 struct qemu_signalfd_siginfo buffer;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030047 size_t offset = 0;
48
Tristan Gingold30faaf72011-02-18 14:17:16 +010049 memset(&buffer, 0, sizeof(buffer));
50 buffer.ssi_signo = sig;
51
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030052 while (offset < sizeof(buffer)) {
53 ssize_t len;
54
Tristan Gingold30faaf72011-02-18 14:17:16 +010055 len = write(info->fd, (char *)&buffer + offset,
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030056 sizeof(buffer) - offset);
57 if (len == -1 && errno == EINTR)
58 continue;
59
60 if (len <= 0) {
Tristan Gingold30faaf72011-02-18 14:17:16 +010061 return NULL;
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030062 }
63
64 offset += len;
65 }
66 }
Tristan Gingold30faaf72011-02-18 14:17:16 +010067 }
Marcelo Tosattidcc38d12010-10-11 15:31:15 -030068}
69
70static int qemu_signalfd_compat(const sigset_t *mask)
71{
72 pthread_attr_t attr;
73 pthread_t tid;
74 struct sigfd_compat_info *info;
75 int fds[2];
76
77 info = malloc(sizeof(*info));
78 if (info == NULL) {
79 errno = ENOMEM;
80 return -1;
81 }
82
83 if (pipe(fds) == -1) {
84 free(info);
85 return -1;
86 }
87
88 qemu_set_cloexec(fds[0]);
89 qemu_set_cloexec(fds[1]);
90
91 memcpy(&info->mask, mask, sizeof(*mask));
92 info->fd = fds[1];
93
94 pthread_attr_init(&attr);
95 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
96
97 pthread_create(&tid, &attr, sigwait_compat, info);
98
99 pthread_attr_destroy(&attr);
100
101 return fds[0];
102}
103
104int qemu_signalfd(const sigset_t *mask)
105{
106#if defined(CONFIG_SIGNALFD)
107 int ret;
108
109 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
110 if (ret != -1) {
111 qemu_set_cloexec(ret);
112 return ret;
113 }
114#endif
115
116 return qemu_signalfd_compat(mask);
117}
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200118
119bool qemu_signalfd_available(void)
120{
121#ifdef CONFIG_SIGNALFD
Peter Maydell7f84c122011-10-13 18:45:37 +0100122 sigset_t mask;
123 int fd;
124 bool ok;
125 sigemptyset(&mask);
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200126 errno = 0;
Peter Maydell7f84c122011-10-13 18:45:37 +0100127 fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
128 ok = (errno != ENOSYS);
129 if (fd >= 0) {
130 close(fd);
131 }
132 return ok;
Jan Kiszkad25f89c2011-06-17 11:25:49 +0200133#else
134 return false;
135#endif
136}