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-char.h"
28 #include "qemu-queue.h"
29
30 #ifndef _WIN32
31 #include <sys/wait.h>
32 #endif
33
34 typedef struct IOHandlerRecord {
35 int fd;
36 IOCanReadHandler *fd_read_poll;
37 IOHandler *fd_read;
38 IOHandler *fd_write;
39 int deleted;
40 void *opaque;
41 QLIST_ENTRY(IOHandlerRecord) next;
42 } IOHandlerRecord;
43
44 static QLIST_HEAD(, IOHandlerRecord) io_handlers =
45 QLIST_HEAD_INITIALIZER(io_handlers);
46
47
48 /* XXX: fd_read_poll should be suppressed, but an API change is
49 necessary in the character devices to suppress fd_can_read(). */
qemu_set_fd_handler2(int fd,IOCanReadHandler * fd_read_poll,IOHandler * fd_read,IOHandler * fd_write,void * opaque)50 int qemu_set_fd_handler2(int fd,
51 IOCanReadHandler *fd_read_poll,
52 IOHandler *fd_read,
53 IOHandler *fd_write,
54 void *opaque)
55 {
56 IOHandlerRecord *ioh;
57
58 if (!fd_read && !fd_write) {
59 QLIST_FOREACH(ioh, &io_handlers, next) {
60 if (ioh->fd == fd) {
61 ioh->deleted = 1;
62 break;
63 }
64 }
65 } else {
66 QLIST_FOREACH(ioh, &io_handlers, next) {
67 if (ioh->fd == fd)
68 goto found;
69 }
70 ioh = qemu_mallocz(sizeof(IOHandlerRecord));
71 QLIST_INSERT_HEAD(&io_handlers, ioh, next);
72 found:
73 ioh->fd = fd;
74 ioh->fd_read_poll = fd_read_poll;
75 ioh->fd_read = fd_read;
76 ioh->fd_write = fd_write;
77 ioh->opaque = opaque;
78 ioh->deleted = 0;
79 }
80 return 0;
81 }
82
qemu_set_fd_handler(int fd,IOHandler * fd_read,IOHandler * fd_write,void * opaque)83 int qemu_set_fd_handler(int fd,
84 IOHandler *fd_read,
85 IOHandler *fd_write,
86 void *opaque)
87 {
88 return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
89 }
90
qemu_iohandler_fill(int * pnfds,fd_set * readfds,fd_set * writefds,fd_set * xfds)91 void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)
92 {
93 IOHandlerRecord *ioh;
94
95 QLIST_FOREACH(ioh, &io_handlers, next) {
96 if (ioh->deleted)
97 continue;
98 if (ioh->fd_read &&
99 (!ioh->fd_read_poll ||
100 ioh->fd_read_poll(ioh->opaque) != 0)) {
101 FD_SET(ioh->fd, readfds);
102 if (ioh->fd > *pnfds)
103 *pnfds = ioh->fd;
104 }
105 if (ioh->fd_write) {
106 FD_SET(ioh->fd, writefds);
107 if (ioh->fd > *pnfds)
108 *pnfds = ioh->fd;
109 }
110 }
111 }
112
qemu_iohandler_poll(fd_set * readfds,fd_set * writefds,fd_set * xfds,int ret)113 void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int ret)
114 {
115 if (ret > 0) {
116 IOHandlerRecord *pioh, *ioh;
117
118 QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
119 if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, readfds)) {
120 ioh->fd_read(ioh->opaque);
121 }
122 if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, writefds)) {
123 ioh->fd_write(ioh->opaque);
124 }
125
126 /* Do this last in case read/write handlers marked it for deletion */
127 if (ioh->deleted) {
128 QLIST_REMOVE(ioh, next);
129 qemu_free(ioh);
130 }
131 }
132 }
133 }
134
135 /* reaping of zombies. right now we're not passing the status to
136 anyone, but it would be possible to add a callback. */
137 #ifndef _WIN32
138 typedef struct ChildProcessRecord {
139 int pid;
140 QLIST_ENTRY(ChildProcessRecord) next;
141 } ChildProcessRecord;
142
143 static QLIST_HEAD(, ChildProcessRecord) child_watches =
144 QLIST_HEAD_INITIALIZER(child_watches);
145
146 static QEMUBH *sigchld_bh;
147
sigchld_handler(int signal)148 static void sigchld_handler(int signal)
149 {
150 qemu_bh_schedule(sigchld_bh);
151 }
152
sigchld_bh_handler(void * opaque)153 static void sigchld_bh_handler(void *opaque)
154 {
155 ChildProcessRecord *rec, *next;
156
157 QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
158 if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
159 QLIST_REMOVE(rec, next);
160 qemu_free(rec);
161 }
162 }
163 }
164
qemu_init_child_watch(void)165 static void qemu_init_child_watch(void)
166 {
167 struct sigaction act;
168 sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
169
170 act.sa_handler = sigchld_handler;
171 act.sa_flags = SA_NOCLDSTOP;
172 sigaction(SIGCHLD, &act, NULL);
173 }
174
qemu_add_child_watch(pid_t pid)175 int qemu_add_child_watch(pid_t pid)
176 {
177 ChildProcessRecord *rec;
178
179 if (!sigchld_bh) {
180 qemu_init_child_watch();
181 }
182
183 QLIST_FOREACH(rec, &child_watches, next) {
184 if (rec->pid == pid) {
185 return 1;
186 }
187 }
188 rec = qemu_mallocz(sizeof(ChildProcessRecord));
189 rec->pid = pid;
190 QLIST_INSERT_HEAD(&child_watches, rec, next);
191 return 0;
192 }
193 #endif
194