balloon: Don't balloon roms
[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/osdep.h"
17 #include "qemu-common.h"
18 #include "qemu/compatfd.h"
19 #include "qemu/thread.h"
20
21 #include <sys/syscall.h>
22
23 struct sigfd_compat_info
24 {
25 sigset_t mask;
26 int fd;
27 };
28
29 static void *sigwait_compat(void *opaque)
30 {
31 struct sigfd_compat_info *info = opaque;
32
33 while (1) {
34 int sig;
35 int err;
36
37 err = sigwait(&info->mask, &sig);
38 if (err != 0) {
39 if (errno == EINTR) {
40 continue;
41 } else {
42 return NULL;
43 }
44 } else {
45 struct qemu_signalfd_siginfo buffer;
46 size_t offset = 0;
47
48 memset(&buffer, 0, sizeof(buffer));
49 buffer.ssi_signo = sig;
50
51 while (offset < sizeof(buffer)) {
52 ssize_t len;
53
54 len = write(info->fd, (char *)&buffer + offset,
55 sizeof(buffer) - offset);
56 if (len == -1 && errno == EINTR)
57 continue;
58
59 if (len <= 0) {
60 return NULL;
61 }
62
63 offset += len;
64 }
65 }
66 }
67 }
68
69 static int qemu_signalfd_compat(const sigset_t *mask)
70 {
71 struct sigfd_compat_info *info;
72 QemuThread thread;
73 int fds[2];
74
75 info = malloc(sizeof(*info));
76 if (info == NULL) {
77 errno = ENOMEM;
78 return -1;
79 }
80
81 if (pipe(fds) == -1) {
82 free(info);
83 return -1;
84 }
85
86 qemu_set_cloexec(fds[0]);
87 qemu_set_cloexec(fds[1]);
88
89 memcpy(&info->mask, mask, sizeof(*mask));
90 info->fd = fds[1];
91
92 qemu_thread_create(&thread, "signalfd_compat", sigwait_compat, info,
93 QEMU_THREAD_DETACHED);
94
95 return fds[0];
96 }
97
98 int qemu_signalfd(const sigset_t *mask)
99 {
100 #if defined(CONFIG_SIGNALFD)
101 int ret;
102
103 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
104 if (ret != -1) {
105 qemu_set_cloexec(ret);
106 return ret;
107 }
108 #endif
109
110 return qemu_signalfd_compat(mask);
111 }