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