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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 DB |
22 | #include "io/channel-command.h" |
23 | #include "io/channel-watch.h" | |
da34e65c | 24 | #include "qapi/error.h" |
0b8fa32f | 25 | #include "qemu/module.h" |
195e14d0 DB |
26 | #include "qemu/sockets.h" |
27 | #include "trace.h" | |
28 | ||
05e50e8f MAL |
29 | /** |
30 | * qio_channel_command_new_pid: | |
31 | * @writefd: the FD connected to the command's stdin | |
32 | * @readfd: the FD connected to the command's stdout | |
a95570e3 | 33 | * @pid: the PID/HANDLE of the running child command |
05e50e8f MAL |
34 | * @errp: pointer to a NULL-initialized error object |
35 | * | |
36 | * Create a channel for performing I/O with the | |
37 | * previously spawned command identified by @pid. | |
38 | * The two file descriptors provide the connection | |
39 | * to command's stdio streams, either one or which | |
40 | * may be -1 to indicate that stream is not open. | |
41 | * | |
42 | * The channel will take ownership of the process | |
43 | * @pid and will kill it when closing the channel. | |
44 | * Similarly it will take responsibility for | |
45 | * closing the file descriptors @writefd and @readfd. | |
46 | * | |
47 | * Returns: the command channel object, or NULL on error | |
48 | */ | |
49 | static QIOChannelCommand * | |
195e14d0 DB |
50 | qio_channel_command_new_pid(int writefd, |
51 | int readfd, | |
a95570e3 | 52 | GPid pid) |
195e14d0 DB |
53 | { |
54 | QIOChannelCommand *ioc; | |
55 | ||
56 | ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND)); | |
57 | ||
58 | ioc->readfd = readfd; | |
59 | ioc->writefd = writefd; | |
60 | ioc->pid = pid; | |
61 | ||
ec5b6c9c MAL |
62 | trace_qio_channel_command_new_pid(ioc, writefd, readfd, |
63 | #ifdef WIN32 | |
64 | GetProcessId(pid) | |
65 | #else | |
66 | pid | |
67 | #endif | |
68 | ); | |
195e14d0 DB |
69 | return ioc; |
70 | } | |
71 | ||
195e14d0 DB |
72 | QIOChannelCommand * |
73 | qio_channel_command_new_spawn(const char *const argv[], | |
74 | int flags, | |
75 | Error **errp) | |
76 | { | |
a95570e3 MAL |
77 | g_autoptr(GError) err = NULL; |
78 | GPid pid = 0; | |
79 | GSpawnFlags gflags = G_SPAWN_CLOEXEC_PIPES | G_SPAWN_DO_NOT_REAP_CHILD; | |
80 | int stdinfd = -1, stdoutfd = -1; | |
195e14d0 DB |
81 | |
82 | flags = flags & O_ACCMODE; | |
a95570e3 | 83 | gflags |= flags == O_WRONLY ? G_SPAWN_STDOUT_TO_DEV_NULL : 0; |
195e14d0 | 84 | |
a95570e3 MAL |
85 | if (!g_spawn_async_with_pipes(NULL, (char **)argv, NULL, gflags, NULL, NULL, |
86 | &pid, | |
87 | flags == O_RDONLY ? NULL : &stdinfd, | |
88 | flags == O_WRONLY ? NULL : &stdoutfd, | |
89 | NULL, &err)) { | |
90 | error_setg(errp, "%s", err->message); | |
91 | return NULL; | |
195e14d0 DB |
92 | } |
93 | ||
a95570e3 | 94 | return qio_channel_command_new_pid(stdinfd, stdoutfd, pid); |
195e14d0 DB |
95 | } |
96 | ||
195e14d0 DB |
97 | #ifndef WIN32 |
98 | static int qio_channel_command_abort(QIOChannelCommand *ioc, | |
99 | Error **errp) | |
100 | { | |
101 | pid_t ret; | |
102 | int status; | |
103 | int step = 0; | |
104 | ||
105 | /* See if intermediate process has exited; if not, try a nice | |
106 | * SIGTERM followed by a more severe SIGKILL. | |
107 | */ | |
108 | rewait: | |
109 | trace_qio_channel_command_abort(ioc, ioc->pid); | |
110 | ret = waitpid(ioc->pid, &status, WNOHANG); | |
111 | trace_qio_channel_command_wait(ioc, ioc->pid, ret, status); | |
112 | if (ret == (pid_t)-1) { | |
113 | if (errno == EINTR) { | |
114 | goto rewait; | |
115 | } else { | |
116 | error_setg_errno(errp, errno, | |
117 | "Cannot wait on pid %llu", | |
118 | (unsigned long long)ioc->pid); | |
119 | return -1; | |
120 | } | |
121 | } else if (ret == 0) { | |
122 | if (step == 0) { | |
123 | kill(ioc->pid, SIGTERM); | |
124 | } else if (step == 1) { | |
125 | kill(ioc->pid, SIGKILL); | |
126 | } else { | |
127 | error_setg(errp, | |
128 | "Process %llu refused to die", | |
129 | (unsigned long long)ioc->pid); | |
130 | return -1; | |
131 | } | |
0c0a55b2 | 132 | step++; |
195e14d0 DB |
133 | usleep(10 * 1000); |
134 | goto rewait; | |
135 | } | |
136 | ||
137 | return 0; | |
138 | } | |
ec5b6c9c MAL |
139 | #else |
140 | static int qio_channel_command_abort(QIOChannelCommand *ioc, | |
141 | Error **errp) | |
142 | { | |
143 | DWORD ret; | |
144 | ||
145 | TerminateProcess(ioc->pid, 0); | |
146 | ret = WaitForSingleObject(ioc->pid, 1000); | |
147 | if (ret != WAIT_OBJECT_0) { | |
148 | error_setg(errp, | |
149 | "Process %llu refused to die", | |
150 | (unsigned long long)GetProcessId(ioc->pid)); | |
151 | return -1; | |
152 | } | |
153 | ||
154 | return 0; | |
155 | } | |
195e14d0 DB |
156 | #endif /* ! WIN32 */ |
157 | ||
158 | ||
159 | static void qio_channel_command_init(Object *obj) | |
160 | { | |
161 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
162 | ioc->readfd = -1; | |
163 | ioc->writefd = -1; | |
a95570e3 | 164 | ioc->pid = 0; |
195e14d0 DB |
165 | } |
166 | ||
167 | static void qio_channel_command_finalize(Object *obj) | |
168 | { | |
169 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
170 | if (ioc->readfd != -1) { | |
171 | close(ioc->readfd); | |
195e14d0 | 172 | } |
e155494c DB |
173 | if (ioc->writefd != -1 && |
174 | ioc->writefd != ioc->readfd) { | |
195e14d0 | 175 | close(ioc->writefd); |
195e14d0 | 176 | } |
e155494c | 177 | ioc->writefd = ioc->readfd = -1; |
195e14d0 | 178 | if (ioc->pid > 0) { |
195e14d0 | 179 | qio_channel_command_abort(ioc, NULL); |
a95570e3 | 180 | g_spawn_close_pid(ioc->pid); |
195e14d0 DB |
181 | } |
182 | } | |
183 | ||
ec5b6c9c MAL |
184 | #ifdef WIN32 |
185 | static bool win32_fd_poll(int fd, gushort events) | |
186 | { | |
187 | GPollFD pfd = { .fd = _get_osfhandle(fd), .events = events }; | |
188 | int res; | |
189 | ||
190 | do { | |
191 | res = g_poll(&pfd, 1, 0); | |
192 | } while (res < 0 && errno == EINTR); | |
193 | if (res == 0) { | |
194 | return false; | |
195 | } | |
196 | ||
197 | return true; | |
198 | } | |
199 | #endif | |
195e14d0 DB |
200 | |
201 | static ssize_t qio_channel_command_readv(QIOChannel *ioc, | |
202 | const struct iovec *iov, | |
203 | size_t niov, | |
204 | int **fds, | |
205 | size_t *nfds, | |
84615a19 | 206 | int flags, |
195e14d0 DB |
207 | Error **errp) |
208 | { | |
209 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
210 | ssize_t ret; | |
211 | ||
ec5b6c9c MAL |
212 | #ifdef WIN32 |
213 | if (!cioc->blocking && !win32_fd_poll(cioc->readfd, G_IO_IN)) { | |
214 | return QIO_CHANNEL_ERR_BLOCK; | |
215 | } | |
216 | #endif | |
217 | ||
195e14d0 DB |
218 | retry: |
219 | ret = readv(cioc->readfd, iov, niov); | |
220 | if (ret < 0) { | |
30fd3e27 | 221 | if (errno == EAGAIN) { |
195e14d0 DB |
222 | return QIO_CHANNEL_ERR_BLOCK; |
223 | } | |
224 | if (errno == EINTR) { | |
225 | goto retry; | |
226 | } | |
227 | ||
228 | error_setg_errno(errp, errno, | |
229 | "Unable to read from command"); | |
230 | return -1; | |
231 | } | |
232 | ||
233 | return ret; | |
234 | } | |
235 | ||
236 | static ssize_t qio_channel_command_writev(QIOChannel *ioc, | |
237 | const struct iovec *iov, | |
238 | size_t niov, | |
239 | int *fds, | |
240 | size_t nfds, | |
b88651cb | 241 | int flags, |
195e14d0 DB |
242 | Error **errp) |
243 | { | |
244 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
245 | ssize_t ret; | |
246 | ||
ec5b6c9c MAL |
247 | #ifdef WIN32 |
248 | if (!cioc->blocking && !win32_fd_poll(cioc->writefd, G_IO_OUT)) { | |
249 | return QIO_CHANNEL_ERR_BLOCK; | |
250 | } | |
251 | #endif | |
252 | ||
195e14d0 DB |
253 | retry: |
254 | ret = writev(cioc->writefd, iov, niov); | |
255 | if (ret <= 0) { | |
30fd3e27 | 256 | if (errno == EAGAIN) { |
195e14d0 DB |
257 | return QIO_CHANNEL_ERR_BLOCK; |
258 | } | |
259 | if (errno == EINTR) { | |
260 | goto retry; | |
261 | } | |
262 | error_setg_errno(errp, errno, "%s", | |
263 | "Unable to write to command"); | |
264 | return -1; | |
265 | } | |
266 | return ret; | |
267 | } | |
268 | ||
269 | static int qio_channel_command_set_blocking(QIOChannel *ioc, | |
270 | bool enabled, | |
271 | Error **errp) | |
272 | { | |
ec5b6c9c MAL |
273 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); |
274 | ||
17fc1245 | 275 | #ifdef WIN32 |
ec5b6c9c | 276 | cioc->blocking = enabled; |
17fc1245 | 277 | #else |
195e14d0 | 278 | |
ec5b6c9c MAL |
279 | if ((cioc->writefd >= 0 && !g_unix_set_fd_nonblocking(cioc->writefd, !enabled, NULL)) || |
280 | (cioc->readfd >= 0 && !g_unix_set_fd_nonblocking(cioc->readfd, !enabled, NULL))) { | |
17fc1245 MAL |
281 | error_setg_errno(errp, errno, "Failed to set FD nonblocking"); |
282 | return -1; | |
195e14d0 | 283 | } |
17fc1245 | 284 | #endif |
195e14d0 DB |
285 | return 0; |
286 | } | |
287 | ||
288 | ||
289 | static int qio_channel_command_close(QIOChannel *ioc, | |
290 | Error **errp) | |
291 | { | |
292 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
293 | int rv = 0; | |
fe823b6f TH |
294 | #ifndef WIN32 |
295 | pid_t wp; | |
296 | #endif | |
195e14d0 DB |
297 | |
298 | /* We close FDs before killing, because that | |
299 | * gives a better chance of clean shutdown | |
300 | */ | |
e155494c DB |
301 | if (cioc->readfd != -1 && |
302 | close(cioc->readfd) < 0) { | |
195e14d0 DB |
303 | rv = -1; |
304 | } | |
e155494c DB |
305 | if (cioc->writefd != -1 && |
306 | cioc->writefd != cioc->readfd && | |
307 | close(cioc->writefd) < 0) { | |
195e14d0 DB |
308 | rv = -1; |
309 | } | |
e155494c | 310 | cioc->writefd = cioc->readfd = -1; |
fe823b6f | 311 | |
195e14d0 | 312 | #ifndef WIN32 |
fe823b6f TH |
313 | do { |
314 | wp = waitpid(cioc->pid, NULL, 0); | |
315 | } while (wp == (pid_t)-1 && errno == EINTR); | |
316 | if (wp == (pid_t)-1) { | |
317 | error_setg_errno(errp, errno, "Failed to wait for pid %llu", | |
318 | (unsigned long long)cioc->pid); | |
195e14d0 DB |
319 | return -1; |
320 | } | |
ec5b6c9c MAL |
321 | #else |
322 | WaitForSingleObject(cioc->pid, INFINITE); | |
195e14d0 | 323 | #endif |
fe823b6f | 324 | |
195e14d0 DB |
325 | if (rv < 0) { |
326 | error_setg_errno(errp, errno, "%s", | |
327 | "Unable to close command"); | |
328 | } | |
329 | return rv; | |
330 | } | |
331 | ||
332 | ||
bf88c124 PB |
333 | static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc, |
334 | AioContext *ctx, | |
335 | IOHandler *io_read, | |
336 | IOHandler *io_write, | |
337 | void *opaque) | |
338 | { | |
339 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
826cc324 SH |
340 | aio_set_fd_handler(ctx, cioc->readfd, false, |
341 | io_read, NULL, NULL, NULL, opaque); | |
342 | aio_set_fd_handler(ctx, cioc->writefd, false, | |
343 | NULL, io_write, NULL, NULL, opaque); | |
bf88c124 PB |
344 | } |
345 | ||
346 | ||
195e14d0 DB |
347 | static GSource *qio_channel_command_create_watch(QIOChannel *ioc, |
348 | GIOCondition condition) | |
349 | { | |
350 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
351 | return qio_channel_create_fd_pair_watch(ioc, | |
352 | cioc->readfd, | |
353 | cioc->writefd, | |
354 | condition); | |
355 | } | |
356 | ||
357 | ||
358 | static void qio_channel_command_class_init(ObjectClass *klass, | |
359 | void *class_data G_GNUC_UNUSED) | |
360 | { | |
361 | QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); | |
362 | ||
363 | ioc_klass->io_writev = qio_channel_command_writev; | |
364 | ioc_klass->io_readv = qio_channel_command_readv; | |
365 | ioc_klass->io_set_blocking = qio_channel_command_set_blocking; | |
366 | ioc_klass->io_close = qio_channel_command_close; | |
367 | ioc_klass->io_create_watch = qio_channel_command_create_watch; | |
bf88c124 | 368 | ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler; |
195e14d0 DB |
369 | } |
370 | ||
371 | static const TypeInfo qio_channel_command_info = { | |
372 | .parent = TYPE_QIO_CHANNEL, | |
373 | .name = TYPE_QIO_CHANNEL_COMMAND, | |
374 | .instance_size = sizeof(QIOChannelCommand), | |
375 | .instance_init = qio_channel_command_init, | |
376 | .instance_finalize = qio_channel_command_finalize, | |
377 | .class_init = qio_channel_command_class_init, | |
378 | }; | |
379 | ||
380 | static void qio_channel_command_register_types(void) | |
381 | { | |
382 | type_register_static(&qio_channel_command_info); | |
383 | } | |
384 | ||
385 | type_init(qio_channel_command_register_types); |