mips: Ensure PC update with MTC0 single-stepping
[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-common.h"
17 #include "qemu/compatfd.h"
18 #include "qemu/thread.h"
19
20 #include <sys/syscall.h>
21
22 struct sigfd_compat_info
23 {
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 if (len <= 0) {
59 return NULL;
60 }
61
62 offset += len;
63 }
64 }
65 }
66 }
67
68 static int qemu_signalfd_compat(const sigset_t *mask)
69 {
70 struct sigfd_compat_info *info;
71 QemuThread thread;
72 int fds[2];
73
74 info = malloc(sizeof(*info));
75 if (info == NULL) {
76 errno = ENOMEM;
77 return -1;
78 }
79
80 if (pipe(fds) == -1) {
81 free(info);
82 return -1;
83 }
84
85 qemu_set_cloexec(fds[0]);
86 qemu_set_cloexec(fds[1]);
87
88 memcpy(&info->mask, mask, sizeof(*mask));
89 info->fd = fds[1];
90
91 qemu_thread_create(&thread, "signalfd_compat", sigwait_compat, info,
92 QEMU_THREAD_DETACHED);
93
94 return fds[0];
95 }
96
97 int qemu_signalfd(const sigset_t *mask)
98 {
99 #if defined(CONFIG_SIGNALFD)
100 int ret;
101
102 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
103 if (ret != -1) {
104 qemu_set_cloexec(ret);
105 return ret;
106 }
107 #endif
108
109 return qemu_signalfd_compat(mask);
110 }
111
112 bool qemu_signalfd_available(void)
113 {
114 #ifdef CONFIG_SIGNALFD
115 sigset_t mask;
116 int fd;
117 bool ok;
118 sigemptyset(&mask);
119 errno = 0;
120 fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
121 ok = (errno != ENOSYS);
122 if (fd >= 0) {
123 close(fd);
124 }
125 return ok;
126 #else
127 return false;
128 #endif
129 }