jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
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/thread.h"
18
19#include <sys/syscall.h>
20
21struct sigfd_compat_info
22{
23 sigset_t mask;
24 int fd;
25};
26
27static void *sigwait_compat(void *opaque)
28{
29 struct sigfd_compat_info *info = opaque;
30
31 while (1) {
32 int sig;
33 int err;
34
35 err = sigwait(&info->mask, &sig);
36 if (err != 0) {
37 if (errno == EINTR) {
38 continue;
39 } else {
40 return NULL;
41 }
42 } else {
43 struct qemu_signalfd_siginfo buffer;
44 size_t offset = 0;
45
46 memset(&buffer, 0, sizeof(buffer));
47 buffer.ssi_signo = sig;
48
49 while (offset < sizeof(buffer)) {
50 ssize_t len;
51
52 len = write(info->fd, (char *)&buffer + offset,
53 sizeof(buffer) - offset);
54 if (len == -1 && errno == EINTR)
55 continue;
56
57 if (len <= 0) {
58 return NULL;
59 }
60
61 offset += len;
62 }
63 }
64 }
65}
66
67static int qemu_signalfd_compat(const sigset_t *mask)
68{
69 struct sigfd_compat_info *info;
70 QemuThread thread;
71 int fds[2];
72
73 info = malloc(sizeof(*info));
74 if (info == NULL) {
75 errno = ENOMEM;
76 return -1;
77 }
78
79 if (pipe(fds) == -1) {
80 free(info);
81 return -1;
82 }
83
84 qemu_set_cloexec(fds[0]);
85 qemu_set_cloexec(fds[1]);
86
87 memcpy(&info->mask, mask, sizeof(*mask));
88 info->fd = fds[1];
89
90 qemu_thread_create(&thread, "signalfd_compat", sigwait_compat, info,
91 QEMU_THREAD_DETACHED);
92
93 return fds[0];
94}
95
96int qemu_signalfd(const sigset_t *mask)
97{
98#if defined(CONFIG_SIGNALFD)
99 int ret;
100
101 ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
102 if (ret != -1) {
103 qemu_set_cloexec(ret);
104 return ret;
105 }
106#endif
107
108 return qemu_signalfd_compat(mask);
109}