PPC: e500: msync is 440 only, e500 has real sync
[qemu.git] / 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 "compatfd.h"
18
19 #include <sys/syscall.h>
20 #include <pthread.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 sigset_t all;
32
33 sigfillset(&all);
34 pthread_sigmask(SIG_BLOCK, &all, NULL);
35
36 while (1) {
37 int sig;
38 int err;
39
40 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;
49 size_t offset = 0;
50
51 memset(&buffer, 0, sizeof(buffer));
52 buffer.ssi_signo = sig;
53
54 while (offset < sizeof(buffer)) {
55 ssize_t len;
56
57 len = write(info->fd, (char *)&buffer + offset,
58 sizeof(buffer) - offset);
59 if (len == -1 && errno == EINTR)
60 continue;
61
62 if (len <= 0) {
63 return NULL;
64 }
65
66 offset += len;
67 }
68 }
69 }
70 }
71
72 static 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
106 int 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 }
120
121 bool qemu_signalfd_available(void)
122 {
123 #ifdef CONFIG_SIGNALFD
124 sigset_t mask;
125 int fd;
126 bool ok;
127 sigemptyset(&mask);
128 errno = 0;
129 fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
130 ok = (errno != ENOSYS);
131 if (fd >= 0) {
132 close(fd);
133 }
134 return ok;
135 #else
136 return false;
137 #endif
138 }