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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 | |
9 | * version 2 of the License, or (at your option) any later version. | |
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" |
195e14d0 DB |
25 | #include "qemu/sockets.h" |
26 | #include "trace.h" | |
27 | ||
28 | ||
29 | QIOChannelCommand * | |
30 | qio_channel_command_new_pid(int writefd, | |
31 | int readfd, | |
32 | pid_t pid) | |
33 | { | |
34 | QIOChannelCommand *ioc; | |
35 | ||
36 | ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND)); | |
37 | ||
38 | ioc->readfd = readfd; | |
39 | ioc->writefd = writefd; | |
40 | ioc->pid = pid; | |
41 | ||
42 | trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid); | |
43 | return ioc; | |
44 | } | |
45 | ||
46 | ||
47 | #ifndef WIN32 | |
48 | QIOChannelCommand * | |
49 | qio_channel_command_new_spawn(const char *const argv[], | |
50 | int flags, | |
51 | Error **errp) | |
52 | { | |
53 | pid_t pid = -1; | |
54 | int stdinfd[2] = { -1, -1 }; | |
55 | int stdoutfd[2] = { -1, -1 }; | |
56 | int devnull = -1; | |
57 | bool stdinnull = false, stdoutnull = false; | |
58 | QIOChannelCommand *ioc; | |
59 | ||
60 | flags = flags & O_ACCMODE; | |
61 | ||
62 | if (flags == O_RDONLY) { | |
63 | stdinnull = true; | |
64 | } | |
65 | if (flags == O_WRONLY) { | |
66 | stdoutnull = true; | |
67 | } | |
68 | ||
69 | if (stdinnull || stdoutnull) { | |
70 | devnull = open("/dev/null", O_RDWR); | |
e155494c | 71 | if (devnull < 0) { |
195e14d0 DB |
72 | error_setg_errno(errp, errno, |
73 | "Unable to open /dev/null"); | |
74 | goto error; | |
75 | } | |
76 | } | |
77 | ||
78 | if ((!stdinnull && pipe(stdinfd) < 0) || | |
79 | (!stdoutnull && pipe(stdoutfd) < 0)) { | |
80 | error_setg_errno(errp, errno, | |
81 | "Unable to open pipe"); | |
82 | goto error; | |
83 | } | |
84 | ||
85 | pid = qemu_fork(errp); | |
86 | if (pid < 0) { | |
87 | goto error; | |
88 | } | |
89 | ||
90 | if (pid == 0) { /* child */ | |
91 | dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO); | |
92 | dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO); | |
93 | /* Leave stderr connected to qemu's stderr */ | |
94 | ||
95 | if (!stdinnull) { | |
96 | close(stdinfd[0]); | |
97 | close(stdinfd[1]); | |
98 | } | |
99 | if (!stdoutnull) { | |
100 | close(stdoutfd[0]); | |
101 | close(stdoutfd[1]); | |
102 | } | |
e155494c DB |
103 | if (devnull != -1) { |
104 | close(devnull); | |
105 | } | |
195e14d0 DB |
106 | |
107 | execv(argv[0], (char * const *)argv); | |
108 | _exit(1); | |
109 | } | |
110 | ||
111 | if (!stdinnull) { | |
112 | close(stdinfd[0]); | |
113 | } | |
114 | if (!stdoutnull) { | |
115 | close(stdoutfd[1]); | |
116 | } | |
117 | ||
118 | ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1], | |
119 | stdoutnull ? devnull : stdoutfd[0], | |
120 | pid); | |
121 | trace_qio_channel_command_new_spawn(ioc, argv[0], flags); | |
122 | return ioc; | |
123 | ||
124 | error: | |
e155494c DB |
125 | if (devnull != -1) { |
126 | close(devnull); | |
127 | } | |
195e14d0 DB |
128 | if (stdinfd[0] != -1) { |
129 | close(stdinfd[0]); | |
130 | } | |
131 | if (stdinfd[1] != -1) { | |
132 | close(stdinfd[1]); | |
133 | } | |
134 | if (stdoutfd[0] != -1) { | |
135 | close(stdoutfd[0]); | |
136 | } | |
137 | if (stdoutfd[1] != -1) { | |
138 | close(stdoutfd[1]); | |
139 | } | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | #else /* WIN32 */ | |
144 | QIOChannelCommand * | |
145 | qio_channel_command_new_spawn(const char *const argv[], | |
146 | int flags, | |
147 | Error **errp) | |
148 | { | |
149 | error_setg_errno(errp, ENOSYS, | |
150 | "Command spawn not supported on this platform"); | |
151 | return NULL; | |
152 | } | |
153 | #endif /* WIN32 */ | |
154 | ||
155 | #ifndef WIN32 | |
156 | static int qio_channel_command_abort(QIOChannelCommand *ioc, | |
157 | Error **errp) | |
158 | { | |
159 | pid_t ret; | |
160 | int status; | |
161 | int step = 0; | |
162 | ||
163 | /* See if intermediate process has exited; if not, try a nice | |
164 | * SIGTERM followed by a more severe SIGKILL. | |
165 | */ | |
166 | rewait: | |
167 | trace_qio_channel_command_abort(ioc, ioc->pid); | |
168 | ret = waitpid(ioc->pid, &status, WNOHANG); | |
169 | trace_qio_channel_command_wait(ioc, ioc->pid, ret, status); | |
170 | if (ret == (pid_t)-1) { | |
171 | if (errno == EINTR) { | |
172 | goto rewait; | |
173 | } else { | |
174 | error_setg_errno(errp, errno, | |
175 | "Cannot wait on pid %llu", | |
176 | (unsigned long long)ioc->pid); | |
177 | return -1; | |
178 | } | |
179 | } else if (ret == 0) { | |
180 | if (step == 0) { | |
181 | kill(ioc->pid, SIGTERM); | |
182 | } else if (step == 1) { | |
183 | kill(ioc->pid, SIGKILL); | |
184 | } else { | |
185 | error_setg(errp, | |
186 | "Process %llu refused to die", | |
187 | (unsigned long long)ioc->pid); | |
188 | return -1; | |
189 | } | |
0c0a55b2 | 190 | step++; |
195e14d0 DB |
191 | usleep(10 * 1000); |
192 | goto rewait; | |
193 | } | |
194 | ||
195 | return 0; | |
196 | } | |
197 | #endif /* ! WIN32 */ | |
198 | ||
199 | ||
200 | static void qio_channel_command_init(Object *obj) | |
201 | { | |
202 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
203 | ioc->readfd = -1; | |
204 | ioc->writefd = -1; | |
205 | ioc->pid = -1; | |
206 | } | |
207 | ||
208 | static void qio_channel_command_finalize(Object *obj) | |
209 | { | |
210 | QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); | |
211 | if (ioc->readfd != -1) { | |
212 | close(ioc->readfd); | |
195e14d0 | 213 | } |
e155494c DB |
214 | if (ioc->writefd != -1 && |
215 | ioc->writefd != ioc->readfd) { | |
195e14d0 | 216 | close(ioc->writefd); |
195e14d0 | 217 | } |
e155494c | 218 | ioc->writefd = ioc->readfd = -1; |
195e14d0 DB |
219 | if (ioc->pid > 0) { |
220 | #ifndef WIN32 | |
221 | qio_channel_command_abort(ioc, NULL); | |
222 | #endif | |
223 | } | |
224 | } | |
225 | ||
226 | ||
227 | static ssize_t qio_channel_command_readv(QIOChannel *ioc, | |
228 | const struct iovec *iov, | |
229 | size_t niov, | |
230 | int **fds, | |
231 | size_t *nfds, | |
232 | Error **errp) | |
233 | { | |
234 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
235 | ssize_t ret; | |
236 | ||
237 | retry: | |
238 | ret = readv(cioc->readfd, iov, niov); | |
239 | if (ret < 0) { | |
30fd3e27 | 240 | if (errno == EAGAIN) { |
195e14d0 DB |
241 | return QIO_CHANNEL_ERR_BLOCK; |
242 | } | |
243 | if (errno == EINTR) { | |
244 | goto retry; | |
245 | } | |
246 | ||
247 | error_setg_errno(errp, errno, | |
248 | "Unable to read from command"); | |
249 | return -1; | |
250 | } | |
251 | ||
252 | return ret; | |
253 | } | |
254 | ||
255 | static ssize_t qio_channel_command_writev(QIOChannel *ioc, | |
256 | const struct iovec *iov, | |
257 | size_t niov, | |
258 | int *fds, | |
259 | size_t nfds, | |
260 | Error **errp) | |
261 | { | |
262 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
263 | ssize_t ret; | |
264 | ||
265 | retry: | |
266 | ret = writev(cioc->writefd, iov, niov); | |
267 | if (ret <= 0) { | |
30fd3e27 | 268 | if (errno == EAGAIN) { |
195e14d0 DB |
269 | return QIO_CHANNEL_ERR_BLOCK; |
270 | } | |
271 | if (errno == EINTR) { | |
272 | goto retry; | |
273 | } | |
274 | error_setg_errno(errp, errno, "%s", | |
275 | "Unable to write to command"); | |
276 | return -1; | |
277 | } | |
278 | return ret; | |
279 | } | |
280 | ||
281 | static int qio_channel_command_set_blocking(QIOChannel *ioc, | |
282 | bool enabled, | |
283 | Error **errp) | |
284 | { | |
285 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
286 | ||
287 | if (enabled) { | |
288 | qemu_set_block(cioc->writefd); | |
289 | qemu_set_block(cioc->readfd); | |
290 | } else { | |
291 | qemu_set_nonblock(cioc->writefd); | |
292 | qemu_set_nonblock(cioc->readfd); | |
293 | } | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
298 | ||
299 | static int qio_channel_command_close(QIOChannel *ioc, | |
300 | Error **errp) | |
301 | { | |
302 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
303 | int rv = 0; | |
fe823b6f TH |
304 | #ifndef WIN32 |
305 | pid_t wp; | |
306 | #endif | |
195e14d0 DB |
307 | |
308 | /* We close FDs before killing, because that | |
309 | * gives a better chance of clean shutdown | |
310 | */ | |
e155494c DB |
311 | if (cioc->readfd != -1 && |
312 | close(cioc->readfd) < 0) { | |
195e14d0 DB |
313 | rv = -1; |
314 | } | |
e155494c DB |
315 | if (cioc->writefd != -1 && |
316 | cioc->writefd != cioc->readfd && | |
317 | close(cioc->writefd) < 0) { | |
195e14d0 DB |
318 | rv = -1; |
319 | } | |
e155494c | 320 | cioc->writefd = cioc->readfd = -1; |
fe823b6f | 321 | |
195e14d0 | 322 | #ifndef WIN32 |
fe823b6f TH |
323 | do { |
324 | wp = waitpid(cioc->pid, NULL, 0); | |
325 | } while (wp == (pid_t)-1 && errno == EINTR); | |
326 | if (wp == (pid_t)-1) { | |
327 | error_setg_errno(errp, errno, "Failed to wait for pid %llu", | |
328 | (unsigned long long)cioc->pid); | |
195e14d0 DB |
329 | return -1; |
330 | } | |
331 | #endif | |
fe823b6f | 332 | |
195e14d0 DB |
333 | if (rv < 0) { |
334 | error_setg_errno(errp, errno, "%s", | |
335 | "Unable to close command"); | |
336 | } | |
337 | return rv; | |
338 | } | |
339 | ||
340 | ||
bf88c124 PB |
341 | static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc, |
342 | AioContext *ctx, | |
343 | IOHandler *io_read, | |
344 | IOHandler *io_write, | |
345 | void *opaque) | |
346 | { | |
347 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
348 | aio_set_fd_handler(ctx, cioc->readfd, false, io_read, NULL, NULL, opaque); | |
349 | aio_set_fd_handler(ctx, cioc->writefd, false, NULL, io_write, NULL, opaque); | |
350 | } | |
351 | ||
352 | ||
195e14d0 DB |
353 | static GSource *qio_channel_command_create_watch(QIOChannel *ioc, |
354 | GIOCondition condition) | |
355 | { | |
356 | QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); | |
357 | return qio_channel_create_fd_pair_watch(ioc, | |
358 | cioc->readfd, | |
359 | cioc->writefd, | |
360 | condition); | |
361 | } | |
362 | ||
363 | ||
364 | static void qio_channel_command_class_init(ObjectClass *klass, | |
365 | void *class_data G_GNUC_UNUSED) | |
366 | { | |
367 | QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); | |
368 | ||
369 | ioc_klass->io_writev = qio_channel_command_writev; | |
370 | ioc_klass->io_readv = qio_channel_command_readv; | |
371 | ioc_klass->io_set_blocking = qio_channel_command_set_blocking; | |
372 | ioc_klass->io_close = qio_channel_command_close; | |
373 | ioc_klass->io_create_watch = qio_channel_command_create_watch; | |
bf88c124 | 374 | ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler; |
195e14d0 DB |
375 | } |
376 | ||
377 | static const TypeInfo qio_channel_command_info = { | |
378 | .parent = TYPE_QIO_CHANNEL, | |
379 | .name = TYPE_QIO_CHANNEL_COMMAND, | |
380 | .instance_size = sizeof(QIOChannelCommand), | |
381 | .instance_init = qio_channel_command_init, | |
382 | .instance_finalize = qio_channel_command_finalize, | |
383 | .class_init = qio_channel_command_class_init, | |
384 | }; | |
385 | ||
386 | static void qio_channel_command_register_types(void) | |
387 | { | |
388 | type_register_static(&qio_channel_command_info); | |
389 | } | |
390 | ||
391 | type_init(qio_channel_command_register_types); |