qemu-img: Omit error_report() after img_open()
[qemu.git] / iohandler.c
1 /*
2 * QEMU System Emulator - managing I/O handler
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "config-host.h"
26 #include "qemu-common.h"
27 #include "qemu/queue.h"
28 #include "block/aio.h"
29 #include "qemu/main-loop.h"
30
31 #ifndef _WIN32
32 #include <sys/wait.h>
33 #endif
34
35 typedef struct IOHandlerRecord {
36 IOCanReadHandler *fd_read_poll;
37 IOHandler *fd_read;
38 IOHandler *fd_write;
39 void *opaque;
40 QLIST_ENTRY(IOHandlerRecord) next;
41 int fd;
42 int pollfds_idx;
43 bool deleted;
44 } IOHandlerRecord;
45
46 static QLIST_HEAD(, IOHandlerRecord) io_handlers =
47 QLIST_HEAD_INITIALIZER(io_handlers);
48
49
50 /* XXX: fd_read_poll should be suppressed, but an API change is
51 necessary in the character devices to suppress fd_can_read(). */
52 int qemu_set_fd_handler2(int fd,
53 IOCanReadHandler *fd_read_poll,
54 IOHandler *fd_read,
55 IOHandler *fd_write,
56 void *opaque)
57 {
58 IOHandlerRecord *ioh;
59
60 assert(fd >= 0);
61
62 if (!fd_read && !fd_write) {
63 QLIST_FOREACH(ioh, &io_handlers, next) {
64 if (ioh->fd == fd) {
65 ioh->deleted = 1;
66 break;
67 }
68 }
69 } else {
70 QLIST_FOREACH(ioh, &io_handlers, next) {
71 if (ioh->fd == fd)
72 goto found;
73 }
74 ioh = g_malloc0(sizeof(IOHandlerRecord));
75 QLIST_INSERT_HEAD(&io_handlers, ioh, next);
76 found:
77 ioh->fd = fd;
78 ioh->fd_read_poll = fd_read_poll;
79 ioh->fd_read = fd_read;
80 ioh->fd_write = fd_write;
81 ioh->opaque = opaque;
82 ioh->pollfds_idx = -1;
83 ioh->deleted = 0;
84 qemu_notify_event();
85 }
86 return 0;
87 }
88
89 int qemu_set_fd_handler(int fd,
90 IOHandler *fd_read,
91 IOHandler *fd_write,
92 void *opaque)
93 {
94 return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
95 }
96
97 void qemu_iohandler_fill(GArray *pollfds)
98 {
99 IOHandlerRecord *ioh;
100
101 QLIST_FOREACH(ioh, &io_handlers, next) {
102 int events = 0;
103
104 if (ioh->deleted)
105 continue;
106 if (ioh->fd_read &&
107 (!ioh->fd_read_poll ||
108 ioh->fd_read_poll(ioh->opaque) != 0)) {
109 events |= G_IO_IN | G_IO_HUP | G_IO_ERR;
110 }
111 if (ioh->fd_write) {
112 events |= G_IO_OUT | G_IO_ERR;
113 }
114 if (events) {
115 GPollFD pfd = {
116 .fd = ioh->fd,
117 .events = events,
118 };
119 ioh->pollfds_idx = pollfds->len;
120 g_array_append_val(pollfds, pfd);
121 } else {
122 ioh->pollfds_idx = -1;
123 }
124 }
125 }
126
127 void qemu_iohandler_poll(GArray *pollfds, int ret)
128 {
129 if (ret > 0) {
130 IOHandlerRecord *pioh, *ioh;
131
132 QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
133 int revents = 0;
134
135 if (!ioh->deleted && ioh->pollfds_idx != -1) {
136 GPollFD *pfd = &g_array_index(pollfds, GPollFD,
137 ioh->pollfds_idx);
138 revents = pfd->revents;
139 }
140
141 if (!ioh->deleted && ioh->fd_read &&
142 (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR))) {
143 ioh->fd_read(ioh->opaque);
144 }
145 if (!ioh->deleted && ioh->fd_write &&
146 (revents & (G_IO_OUT | G_IO_ERR))) {
147 ioh->fd_write(ioh->opaque);
148 }
149
150 /* Do this last in case read/write handlers marked it for deletion */
151 if (ioh->deleted) {
152 QLIST_REMOVE(ioh, next);
153 g_free(ioh);
154 }
155 }
156 }
157 }
158
159 /* reaping of zombies. right now we're not passing the status to
160 anyone, but it would be possible to add a callback. */
161 #ifndef _WIN32
162 typedef struct ChildProcessRecord {
163 int pid;
164 QLIST_ENTRY(ChildProcessRecord) next;
165 } ChildProcessRecord;
166
167 static QLIST_HEAD(, ChildProcessRecord) child_watches =
168 QLIST_HEAD_INITIALIZER(child_watches);
169
170 static QEMUBH *sigchld_bh;
171
172 static void sigchld_handler(int signal)
173 {
174 qemu_bh_schedule(sigchld_bh);
175 }
176
177 static void sigchld_bh_handler(void *opaque)
178 {
179 ChildProcessRecord *rec, *next;
180
181 QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
182 if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
183 QLIST_REMOVE(rec, next);
184 g_free(rec);
185 }
186 }
187 }
188
189 static void qemu_init_child_watch(void)
190 {
191 struct sigaction act;
192 sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
193
194 memset(&act, 0, sizeof(act));
195 act.sa_handler = sigchld_handler;
196 act.sa_flags = SA_NOCLDSTOP;
197 sigaction(SIGCHLD, &act, NULL);
198 }
199
200 int qemu_add_child_watch(pid_t pid)
201 {
202 ChildProcessRecord *rec;
203
204 if (!sigchld_bh) {
205 qemu_init_child_watch();
206 }
207
208 QLIST_FOREACH(rec, &child_watches, next) {
209 if (rec->pid == pid) {
210 return 1;
211 }
212 }
213 rec = g_malloc0(sizeof(ChildProcessRecord));
214 rec->pid = pid;
215 QLIST_INSERT_HEAD(&child_watches, rec, next);
216 return 0;
217 }
218 #endif