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195e14d0 DB |
1 | /* |
2 | * QEMU I/O channels external command driver | |
3 | * | |
4 | * Copyright (c) 2015 Red Hat, Inc. | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
c8198bd5 | 9 | * version 2.1 of the License, or (at your option) any later version. |
195e14d0 DB |
10 | * |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
18 | * | |
19 | */ | |
20 | ||
cae9fc56 | 21 | #include "qemu/osdep.h" |
195e14d0 | 22 | #include "io/channel-command.h" |
06e0f098 | 23 | #include "io/channel-util.h" |
195e14d0 | 24 | #include "io/channel-watch.h" |
da34e65c | 25 | #include "qapi/error.h" |
0b8fa32f | 26 | #include "qemu/module.h" |
195e14d0 DB |
27 | #include "qemu/sockets.h" |
28 | #include "trace.h" | |
29 | ||
05e50e8f MAL |
30 | /** |
31 | * qio_channel_command_new_pid: | |
32 | * @writefd: the FD connected to the command's stdin | |
33 | * @readfd: the FD connected to the command's stdout | |
a95570e3 | 34 | * @pid: the PID/HANDLE of the running child command |
05e50e8f MAL |
35 | * @errp: pointer to a NULL-initialized error object |
36 | * | |
37 | * Create a channel for performing I/O with the | |
38 | * previously spawned command identified by @pid. | |
39 | * The two file descriptors provide the connection | |
40 | * to command's stdio streams, either one or which | |
41 | * may be -1 to indicate that stream is not open. | |
42 | * | |
43 | * The channel will take ownership of the process | |
44 | * @pid and will kill it when closing the channel. | |
45 | * Similarly it will take responsibility for | |
46 | * closing the file descriptors @writefd and @readfd. | |
47 | * | |
48 | * Returns: the command channel object, or NULL on error | |
49 | */ | |
50 | static QIOChannelCommand * | |
195e14d0 DB |
51 | qio_channel_command_new_pid(int writefd, |
52 | int readfd, | |
a95570e3 | 53 | GPid pid) |
195e14d0 DB |
54 | { |
55 | QIOChannelCommand *ioc; | |
56 | ||
57 | ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND)); | |
58 | ||
59 | ioc->readfd = readfd; | |
60 | ioc->writefd = writefd; | |
61 | ioc->pid = pid; | |
62 | ||
ec5b6c9c MAL |
63 | trace_qio_channel_command_new_pid(ioc, writefd, readfd, |
64 | #ifdef WIN32 | |
65 | GetProcessId(pid) | |
66 | #else | |
67 | pid | |
68 | #endif | |
69 | ); | |
195e14d0 DB |
70 | return ioc; |
71 | } | |
72 | ||
195e14d0 DB |
73 | QIOChannelCommand * |
74 | qio_channel_command_new_spawn(const char *const argv[], | |
75 | int flags, | |
76 | Error **errp) | |
77 | { | |
a95570e3 MAL |
78 | g_autoptr(GError) err = NULL; |
79 | GPid pid = 0; | |
80 | GSpawnFlags gflags = G_SPAWN_CLOEXEC_PIPES | G_SPAWN_DO_NOT_REAP_CHILD; | |
81 | int stdinfd = -1, stdoutfd = -1; | |
195e14d0 DB |
82 | |
83 | flags = flags & O_ACCMODE; | |
a95570e3 | 84 | gflags |= flags == O_WRONLY ? G_SPAWN_STDOUT_TO_DEV_NULL : 0; |
195e14d0 | 85 | |
a95570e3 MAL |
86 | if (!g_spawn_async_with_pipes(NULL, (char **)argv, NULL, gflags, NULL, NULL, |
87 | &pid, | |
88 | flags == O_RDONLY ? NULL : &stdinfd, | |
89 | flags == O_WRONLY ? NULL : &stdoutfd, | |
90 | NULL, &err)) { | |
91 | error_setg(errp, "%s", err->message); | |
92 | return NULL; | |
195e14d0 DB |
93 | } |
94 | ||
a95570e3 | 95 | return qio_channel_command_new_pid(stdinfd, stdoutfd, pid); |
195e14d0 DB |
96 | } |
97 | ||
195e14d0 DB |
98 | #ifndef WIN32 |
99 | static int qio_channel_command_abort(QIOChannelCommand *ioc, | |
100 | Error **errp) | |
101 | { | |
102 | pid_t ret; | |
103 | int status; | |
104 | int step = 0; | |
105 | ||
106 | /* See if intermediate process has exited; if not, try a nice | |
107 | * SIGTERM followed by a more severe SIGKILL. | |
108 | */ | |
109 | rewait: | |
110 | trace_qio_channel_command_abort(ioc, ioc->pid); | |
111 | ret = waitpid(ioc->pid, &status, WNOHANG); | |
112 | trace_qio_channel_command_wait(ioc, ioc->pid, ret, status); | |
113 | if (ret == (pid_t)-1) { | |
114 | if (errno == EINTR) { | |
115 | goto rewait; | |
116 | } else { | |
117 | error_setg_errno(errp, errno, | |
118 | "Cannot wait on pid %llu", | |
119 | (unsigned long long)ioc->pid); | |
120 | return -1; | |
121 | } | |
122 | } else if (ret == 0) { | |
123 | if (step == 0) { | |
124 | kill(ioc->pid, SIGTERM); | |
125 | } else if (step == 1) { | |
126 | kill(ioc->pid, SIGKILL); | |
127 | } else { | |
128 | error_setg(errp, | |
129 | "Process %llu refused to die", | |
130 | (unsigned long long)ioc->pid); | |
131 | return -1; | |
132 | } | |
0c0a55b2 | 133 | step++; |
195e14d0 DB |
134 | usleep(10 * 1000); |
135 | goto rewait; | |
136 | } | |
137 | ||
138 | return 0; | |
139 | } | |
ec5b6c9c MAL |
140 | #else |
141 | static int qio_channel_command_abort(QIOChannelCommand *ioc, | |
142 | Error **errp) | |
143 | { | |
144 | DWORD ret; | |
145 | ||
146 | TerminateProcess(ioc->pid, 0); | |
147 | ret = WaitForSingleObject(ioc->pid, 1000); | |
148 | if (ret != WAIT_OBJECT_0) { | |
149 | error_setg(errp, | |
150 | "Process %llu refused to die", | |
151 | (unsigned long long)GetProcessId(ioc->pid)); | |
152 | return -1; | |
153 | } | |
154 | ||
155 | return 0; | |
156 | } | |
195e14d0 DB |
157 | #endif /* ! WIN32 */ |
158 | ||
159 | ||
160 | static void qio_channel_command_init(Object *obj) | |
161 | { | |
162 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
163 | ioc->readfd = -1; | |
164 | ioc->writefd = -1; | |
a95570e3 | 165 | ioc->pid = 0; |
195e14d0 DB |
166 | } |
167 | ||
168 | static void qio_channel_command_finalize(Object *obj) | |
169 | { | |
170 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
171 | if (ioc->readfd != -1) { | |
172 | close(ioc->readfd); | |
195e14d0 | 173 | } |
e155494c DB |
174 | if (ioc->writefd != -1 && |
175 | ioc->writefd != ioc->readfd) { | |
195e14d0 | 176 | close(ioc->writefd); |
195e14d0 | 177 | } |
e155494c | 178 | ioc->writefd = ioc->readfd = -1; |
195e14d0 | 179 | if (ioc->pid > 0) { |
195e14d0 | 180 | qio_channel_command_abort(ioc, NULL); |
a95570e3 | 181 | g_spawn_close_pid(ioc->pid); |
195e14d0 DB |
182 | } |
183 | } | |
184 | ||
ec5b6c9c MAL |
185 | #ifdef WIN32 |
186 | static bool win32_fd_poll(int fd, gushort events) | |
187 | { | |
188 | GPollFD pfd = { .fd = _get_osfhandle(fd), .events = events }; | |
189 | int res; | |
190 | ||
191 | do { | |
192 | res = g_poll(&pfd, 1, 0); | |
193 | } while (res < 0 && errno == EINTR); | |
194 | if (res == 0) { | |
195 | return false; | |
196 | } | |
197 | ||
198 | return true; | |
199 | } | |
200 | #endif | |
195e14d0 DB |
201 | |
202 | static ssize_t qio_channel_command_readv(QIOChannel *ioc, | |
203 | const struct iovec *iov, | |
204 | size_t niov, | |
205 | int **fds, | |
206 | size_t *nfds, | |
84615a19 | 207 | int flags, |
195e14d0 DB |
208 | Error **errp) |
209 | { | |
210 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
211 | ssize_t ret; | |
212 | ||
ec5b6c9c MAL |
213 | #ifdef WIN32 |
214 | if (!cioc->blocking && !win32_fd_poll(cioc->readfd, G_IO_IN)) { | |
215 | return QIO_CHANNEL_ERR_BLOCK; | |
216 | } | |
217 | #endif | |
218 | ||
195e14d0 DB |
219 | retry: |
220 | ret = readv(cioc->readfd, iov, niov); | |
221 | if (ret < 0) { | |
30fd3e27 | 222 | if (errno == EAGAIN) { |
195e14d0 DB |
223 | return QIO_CHANNEL_ERR_BLOCK; |
224 | } | |
225 | if (errno == EINTR) { | |
226 | goto retry; | |
227 | } | |
228 | ||
229 | error_setg_errno(errp, errno, | |
230 | "Unable to read from command"); | |
231 | return -1; | |
232 | } | |
233 | ||
234 | return ret; | |
235 | } | |
236 | ||
237 | static ssize_t qio_channel_command_writev(QIOChannel *ioc, | |
238 | const struct iovec *iov, | |
239 | size_t niov, | |
240 | int *fds, | |
241 | size_t nfds, | |
b88651cb | 242 | int flags, |
195e14d0 DB |
243 | Error **errp) |
244 | { | |
245 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
246 | ssize_t ret; | |
247 | ||
ec5b6c9c MAL |
248 | #ifdef WIN32 |
249 | if (!cioc->blocking && !win32_fd_poll(cioc->writefd, G_IO_OUT)) { | |
250 | return QIO_CHANNEL_ERR_BLOCK; | |
251 | } | |
252 | #endif | |
253 | ||
195e14d0 DB |
254 | retry: |
255 | ret = writev(cioc->writefd, iov, niov); | |
256 | if (ret <= 0) { | |
30fd3e27 | 257 | if (errno == EAGAIN) { |
195e14d0 DB |
258 | return QIO_CHANNEL_ERR_BLOCK; |
259 | } | |
260 | if (errno == EINTR) { | |
261 | goto retry; | |
262 | } | |
263 | error_setg_errno(errp, errno, "%s", | |
264 | "Unable to write to command"); | |
265 | return -1; | |
266 | } | |
267 | return ret; | |
268 | } | |
269 | ||
270 | static int qio_channel_command_set_blocking(QIOChannel *ioc, | |
271 | bool enabled, | |
272 | Error **errp) | |
273 | { | |
ec5b6c9c MAL |
274 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); |
275 | ||
17fc1245 | 276 | #ifdef WIN32 |
ec5b6c9c | 277 | cioc->blocking = enabled; |
17fc1245 | 278 | #else |
195e14d0 | 279 | |
ec5b6c9c MAL |
280 | if ((cioc->writefd >= 0 && !g_unix_set_fd_nonblocking(cioc->writefd, !enabled, NULL)) || |
281 | (cioc->readfd >= 0 && !g_unix_set_fd_nonblocking(cioc->readfd, !enabled, NULL))) { | |
17fc1245 MAL |
282 | error_setg_errno(errp, errno, "Failed to set FD nonblocking"); |
283 | return -1; | |
195e14d0 | 284 | } |
17fc1245 | 285 | #endif |
195e14d0 DB |
286 | return 0; |
287 | } | |
288 | ||
289 | ||
290 | static int qio_channel_command_close(QIOChannel *ioc, | |
291 | Error **errp) | |
292 | { | |
293 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
294 | int rv = 0; | |
fe823b6f TH |
295 | #ifndef WIN32 |
296 | pid_t wp; | |
297 | #endif | |
195e14d0 DB |
298 | |
299 | /* We close FDs before killing, because that | |
300 | * gives a better chance of clean shutdown | |
301 | */ | |
e155494c DB |
302 | if (cioc->readfd != -1 && |
303 | close(cioc->readfd) < 0) { | |
195e14d0 DB |
304 | rv = -1; |
305 | } | |
e155494c DB |
306 | if (cioc->writefd != -1 && |
307 | cioc->writefd != cioc->readfd && | |
308 | close(cioc->writefd) < 0) { | |
195e14d0 DB |
309 | rv = -1; |
310 | } | |
e155494c | 311 | cioc->writefd = cioc->readfd = -1; |
fe823b6f | 312 | |
195e14d0 | 313 | #ifndef WIN32 |
fe823b6f TH |
314 | do { |
315 | wp = waitpid(cioc->pid, NULL, 0); | |
316 | } while (wp == (pid_t)-1 && errno == EINTR); | |
317 | if (wp == (pid_t)-1) { | |
318 | error_setg_errno(errp, errno, "Failed to wait for pid %llu", | |
319 | (unsigned long long)cioc->pid); | |
195e14d0 DB |
320 | return -1; |
321 | } | |
ec5b6c9c MAL |
322 | #else |
323 | WaitForSingleObject(cioc->pid, INFINITE); | |
195e14d0 | 324 | #endif |
fe823b6f | 325 | |
195e14d0 DB |
326 | if (rv < 0) { |
327 | error_setg_errno(errp, errno, "%s", | |
328 | "Unable to close command"); | |
329 | } | |
330 | return rv; | |
331 | } | |
332 | ||
333 | ||
bf88c124 | 334 | static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc, |
06e0f098 | 335 | AioContext *read_ctx, |
bf88c124 | 336 | IOHandler *io_read, |
06e0f098 | 337 | AioContext *write_ctx, |
bf88c124 PB |
338 | IOHandler *io_write, |
339 | void *opaque) | |
340 | { | |
341 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
06e0f098 SH |
342 | |
343 | qio_channel_util_set_aio_fd_handler(cioc->readfd, read_ctx, io_read, | |
344 | cioc->writefd, write_ctx, io_write, | |
345 | opaque); | |
bf88c124 PB |
346 | } |
347 | ||
348 | ||
195e14d0 DB |
349 | static GSource *qio_channel_command_create_watch(QIOChannel *ioc, |
350 | GIOCondition condition) | |
351 | { | |
352 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
353 | return qio_channel_create_fd_pair_watch(ioc, | |
354 | cioc->readfd, | |
355 | cioc->writefd, | |
356 | condition); | |
357 | } | |
358 | ||
359 | ||
360 | static void qio_channel_command_class_init(ObjectClass *klass, | |
361 | void *class_data G_GNUC_UNUSED) | |
362 | { | |
363 | QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); | |
364 | ||
365 | ioc_klass->io_writev = qio_channel_command_writev; | |
366 | ioc_klass->io_readv = qio_channel_command_readv; | |
367 | ioc_klass->io_set_blocking = qio_channel_command_set_blocking; | |
368 | ioc_klass->io_close = qio_channel_command_close; | |
369 | ioc_klass->io_create_watch = qio_channel_command_create_watch; | |
bf88c124 | 370 | ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler; |
195e14d0 DB |
371 | } |
372 | ||
373 | static const TypeInfo qio_channel_command_info = { | |
374 | .parent = TYPE_QIO_CHANNEL, | |
375 | .name = TYPE_QIO_CHANNEL_COMMAND, | |
376 | .instance_size = sizeof(QIOChannelCommand), | |
377 | .instance_init = qio_channel_command_init, | |
378 | .instance_finalize = qio_channel_command_finalize, | |
379 | .class_init = qio_channel_command_class_init, | |
380 | }; | |
381 | ||
382 | static void qio_channel_command_register_types(void) | |
383 | { | |
384 | type_register_static(&qio_channel_command_info); | |
385 | } | |
386 | ||
387 | type_init(qio_channel_command_register_types); |