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 */
13
14 #include "qemu-common.h"
15 #include "compatfd.h"
16
17 #include <sys/syscall.h>
18 #include <pthread.h>
19
20 struct sigfd_compat_info
21 {
22 sigset_t mask;
23 int fd;
24 };
25
sigwait_compat(void * opaque)26 static void *sigwait_compat(void *opaque)
27 {
28 struct sigfd_compat_info *info = opaque;
29 int err;
30 sigset_t all;
31
32 sigfillset(&all);
33 sigprocmask(SIG_BLOCK, &all, NULL);
34
35 do {
36 siginfo_t siginfo;
37
38 err = sigwaitinfo(&info->mask, &siginfo);
39 if (err == -1 && errno == EINTR) {
40 err = 0;
41 continue;
42 }
43
44 if (err > 0) {
45 char buffer[128];
46 size_t offset = 0;
47
48 memcpy(buffer, &err, sizeof(err));
49 while (offset < sizeof(buffer)) {
50 ssize_t len;
51
52 len = write(info->fd, buffer + offset,
53 sizeof(buffer) - offset);
54 if (len == -1 && errno == EINTR)
55 continue;
56
57 if (len <= 0) {
58 err = -1;
59 break;
60 }
61
62 offset += len;
63 }
64 }
65 } while (err >= 0);
66
67 return NULL;
68 }
69
qemu_signalfd_compat(const sigset_t * mask)70 static 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 memcpy(&info->mask, mask, sizeof(*mask));
89 info->fd = fds[1];
90
91 pthread_attr_init(&attr);
92 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
93
94 pthread_create(&tid, &attr, sigwait_compat, info);
95
96 pthread_attr_destroy(&attr);
97
98 return fds[0];
99 }
100
qemu_signalfd(const sigset_t * mask)101 int qemu_signalfd(const sigset_t *mask)
102 {
103 #if defined(SYS_signalfd)
104 int ret;
105
106 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
107 if (!(ret == -1 && errno == ENOSYS))
108 return ret;
109 #endif
110
111 return qemu_signalfd_compat(mask);
112 }
113
qemu_eventfd(int * fds)114 int qemu_eventfd(int *fds)
115 {
116 #if defined(SYS_eventfd)
117 int ret;
118
119 ret = syscall(SYS_eventfd, 0);
120 if (ret >= 0) {
121 fds[0] = fds[1] = ret;
122 return 0;
123 } else if (!(ret == -1 && errno == ENOSYS))
124 return ret;
125 #endif
126
127 return pipe(fds);
128 }
129