blockd: don't flush devices list on "hotplug" call
[project/fstools.git] / blockd.c
1 #include <sys/types.h>
2 #include <sys/stat.h>
3 #include <sys/mount.h>
4 #include <sys/wait.h>
5
6 #include <stdlib.h>
7 #include <stdio.h>
8 #include <unistd.h>
9 #include <fcntl.h>
10
11 #include <errno.h>
12
13 #include <linux/limits.h>
14 #include <linux/auto_fs4.h>
15
16 #include <libubox/uloop.h>
17 #include <libubox/vlist.h>
18 #include <libubox/ulog.h>
19 #include <libubox/avl-cmp.h>
20 #include <libubus.h>
21
22 #include "libfstools/libfstools.h"
23
24 #define AUTOFS_MOUNT_PATH "/tmp/run/blockd/"
25 #define AUTOFS_TIMEOUT 30
26 #define AUTOFS_EXPIRE_TIMER (5 * 1000)
27
28 struct device {
29 struct vlist_node node;
30 struct blob_attr *msg;
31 char *name;
32 char *target;
33 int autofs;
34 int anon;
35 };
36
37 static struct uloop_fd fd_autofs_read;
38 static int fd_autofs_write = 0;
39 static struct ubus_auto_conn conn;
40 struct blob_buf bb = { 0 };
41
42 enum {
43 MOUNT_UUID,
44 MOUNT_LABEL,
45 MOUNT_ENABLE,
46 MOUNT_TARGET,
47 MOUNT_DEVICE,
48 MOUNT_OPTIONS,
49 MOUNT_AUTOFS,
50 MOUNT_ANON,
51 MOUNT_REMOVE,
52 __MOUNT_MAX
53 };
54
55 static const struct blobmsg_policy mount_policy[__MOUNT_MAX] = {
56 [MOUNT_UUID] = { .name = "uuid", .type = BLOBMSG_TYPE_STRING },
57 [MOUNT_LABEL] = { .name = "label", .type = BLOBMSG_TYPE_STRING },
58 [MOUNT_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
59 [MOUNT_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
60 [MOUNT_OPTIONS] = { .name = "options", .type = BLOBMSG_TYPE_STRING },
61 [MOUNT_ENABLE] = { .name = "enabled", .type = BLOBMSG_TYPE_INT32 },
62 [MOUNT_AUTOFS] = { .name = "autofs", .type = BLOBMSG_TYPE_INT32 },
63 [MOUNT_ANON] = { .name = "anon", .type = BLOBMSG_TYPE_INT32 },
64 [MOUNT_REMOVE] = { .name = "remove", .type = BLOBMSG_TYPE_INT32 },
65 };
66
67 static char*
68 _find_mount_point(char *device)
69 {
70 char dev[32] = { 0 };
71
72 snprintf(dev, sizeof(dev), "/dev/%s", device);
73
74 return find_mount_point(dev, 0);
75 }
76
77 static int
78 block(char *cmd, char *action, char *device)
79 {
80 pid_t pid = fork();
81 int ret = -1;
82 int status;
83 char *argv[5] = { 0 };
84 int a = 0;
85
86 switch (pid) {
87 case -1:
88 ULOG_ERR("failed to fork block process\n");
89 break;
90
91 case 0:
92 argv[a++] = "/sbin/block";
93 argv[a++] = cmd;
94 argv[a++] = action;
95 argv[a++] = device;
96 execvp(argv[0], argv);
97 ULOG_ERR("failed to spawn %s %s %s\n", *argv, action, device);
98 exit(EXIT_FAILURE);
99
100 default:
101 waitpid(pid, &status, 0);
102 ret = WEXITSTATUS(status);
103 if (ret)
104 ULOG_ERR("failed to run block. %s/%s\n", action, device);
105 break;
106 }
107
108 return ret;
109 }
110
111 static void
112 device_free(struct device *device)
113 {
114 char *mp;
115
116 if (!device->autofs)
117 return;
118
119 block("autofs", "unavailable", device->name);
120
121 if (device->target)
122 unlink(device->target);
123
124 mp = _find_mount_point(device->name);
125 if (mp) {
126 block("autofs", "remove", device->name);
127 free(mp);
128 }
129 }
130
131 static void
132 device_add(struct device *device)
133 {
134 char path[64];
135
136 if (!device->autofs)
137 return;
138
139 snprintf(path, sizeof(path), "/tmp/run/blockd/%s", device->name);
140 if (symlink(path, device->target))
141 ULOG_ERR("failed to symlink %s->%s\n", device->target, path);
142 else
143 block("autofs", "available", device->name);
144 }
145
146 static int
147 device_move(struct device *device_o, struct device *device_n)
148 {
149 char path[64];
150
151 if (device_o->autofs != device_n->autofs)
152 return -1;
153
154 if (device_o->anon || device_n->anon)
155 return -1;
156
157 if (device_o->autofs) {
158 unlink(device_o->target);
159 snprintf(path, sizeof(path), "/tmp/run/blockd/%s", device_n->name);
160 if (symlink(path, device_n->target))
161 ULOG_ERR("failed to symlink %s->%s\n", device_n->target, path);
162 } else {
163 mkdir(device_n->target, 0755);
164 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
165 rmdir(device_n->target);
166 else
167 rmdir(device_o->target);
168 }
169
170 return 0;
171 }
172
173 static void
174 devices_update_cb(struct vlist_tree *tree, struct vlist_node *node_new,
175 struct vlist_node *node_old)
176 {
177 struct device *device_o = NULL, *device_n = NULL;
178
179 if (node_old)
180 device_o = container_of(node_old, struct device, node);
181
182 if (node_new)
183 device_n = container_of(node_new, struct device, node);
184
185 if (device_o && device_n) {
186 if (device_move(device_o, device_n)) {
187 device_free(device_o);
188 device_add(device_n);
189 if (!device_n->autofs)
190 block("mount", NULL, NULL);
191 }
192 } else if (device_n) {
193 device_add(device_n);
194 } else {
195 device_free(device_o);
196 }
197
198 if (device_o)
199 free(device_o);
200 }
201
202 VLIST_TREE(devices, avl_strcmp, devices_update_cb, false, false);
203
204 static int
205 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
206 struct ubus_request_data *req, const char *method,
207 struct blob_attr *msg)
208 {
209 struct blob_attr *data[__MOUNT_MAX];
210 struct device *device;
211 struct blob_attr *_msg;
212 char *devname, *_name;
213 char *target = NULL, *__target;
214 char _target[32];
215
216 blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
217
218 if (!data[MOUNT_DEVICE])
219 return UBUS_STATUS_INVALID_ARGUMENT;
220
221 devname = blobmsg_get_string(data[MOUNT_DEVICE]);
222
223 if (data[MOUNT_TARGET]) {
224 target = blobmsg_get_string(data[MOUNT_TARGET]);
225 } else {
226 snprintf(_target, sizeof(_target), "/mnt/%s",
227 blobmsg_get_string(data[MOUNT_DEVICE]));
228 target = _target;
229 }
230
231 if (data[MOUNT_REMOVE])
232 device = vlist_find(&devices, devname, device, node);
233 else
234 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
235 &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
236
237 if (!device)
238 return UBUS_STATUS_UNKNOWN_ERROR;
239
240 if (data[MOUNT_REMOVE]) {
241 vlist_delete(&devices, &device->node);
242 } else {
243 if (data[MOUNT_AUTOFS])
244 device->autofs = blobmsg_get_u32(data[MOUNT_AUTOFS]);
245 else
246 device->autofs = 0;
247 if (data[MOUNT_ANON])
248 device->anon = blobmsg_get_u32(data[MOUNT_ANON]);
249 else
250 device->anon = 0;
251 device->msg = _msg;
252 memcpy(_msg, msg, blob_raw_len(msg));
253 device->name = _name;
254 strcpy(_name, devname);
255 device->target = __target;
256 strcpy(__target, target);
257 vlist_add(&devices, &device->node, device->name);
258 }
259
260 return 0;
261 }
262
263 static int
264 block_info(struct ubus_context *ctx, struct ubus_object *obj,
265 struct ubus_request_data *req, const char *method,
266 struct blob_attr *msg)
267 {
268 struct device *device;
269 void *a;
270
271 blob_buf_init(&bb, 0);
272 a = blobmsg_open_array(&bb, "devices");
273 vlist_for_each_element(&devices, device, node) {
274 void *t = blobmsg_open_table(&bb, "");
275 struct blob_attr *v;
276 char *mp;
277 int rem;
278
279 blob_for_each_attr(v, device->msg, rem)
280 blobmsg_add_blob(&bb, v);
281
282 mp = _find_mount_point(device->name);
283 if (mp) {
284 blobmsg_add_string(&bb, "mount", mp);
285 free(mp);
286 }
287 blobmsg_close_table(&bb, t);
288 }
289 blobmsg_close_array(&bb, a);
290 ubus_send_reply(ctx, req, bb.head);
291
292 return 0;
293 }
294
295 static const struct ubus_method block_methods[] = {
296 UBUS_METHOD("hotplug", block_hotplug, mount_policy),
297 UBUS_METHOD_NOARG("info", block_info),
298 };
299
300 static struct ubus_object_type block_object_type =
301 UBUS_OBJECT_TYPE("block", block_methods);
302
303 static struct ubus_object block_object = {
304 .name = "block",
305 .type = &block_object_type,
306 .methods = block_methods,
307 .n_methods = ARRAY_SIZE(block_methods),
308 };
309
310 static void
311 ubus_connect_handler(struct ubus_context *ctx)
312 {
313 int ret;
314
315 ret = ubus_add_object(ctx, &block_object);
316 if (ret)
317 fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
318 }
319
320 static int autofs_umount(void)
321 {
322 umount2(AUTOFS_MOUNT_PATH, MNT_DETACH);
323 return 0;
324 }
325
326 static void autofs_read_handler(struct uloop_fd *u, unsigned int events)
327 {
328 union autofs_v5_packet_union pktu;
329 const struct autofs_v5_packet *pkt;
330 int cmd = AUTOFS_IOC_READY;
331 struct stat st;
332
333 while (read(u->fd, &pktu, sizeof(pktu)) == -1) {
334 if (errno != EINTR)
335 return;
336 continue;
337 }
338
339 if (pktu.hdr.type != autofs_ptype_missing_indirect) {
340 ULOG_ERR("unknown packet type %d\n", pktu.hdr.type);
341 return;
342 }
343
344 pkt = &pktu.missing_indirect;
345 ULOG_ERR("kernel is requesting a mount -> %s\n", pkt->name);
346 if (lstat(pkt->name, &st) == -1)
347 if (block("autofs", "add", (char *)pkt->name))
348 cmd = AUTOFS_IOC_FAIL;
349
350 if (ioctl(fd_autofs_write, cmd, pkt->wait_queue_token) < 0)
351 ULOG_ERR("failed to report back to kernel\n");
352 }
353
354 static void autofs_expire(struct uloop_timeout *t)
355 {
356 struct autofs_packet_expire pkt;
357
358 while (ioctl(fd_autofs_write, AUTOFS_IOC_EXPIRE, &pkt) == 0)
359 block("autofs", "remove", pkt.name);
360
361 uloop_timeout_set(t, AUTOFS_EXPIRE_TIMER);
362 }
363
364 struct uloop_timeout autofs_expire_timer = {
365 .cb = autofs_expire,
366 };
367
368 static int autofs_mount(void)
369 {
370 int autofs_timeout = AUTOFS_TIMEOUT;
371 int kproto_version;
372 int pipefd[2];
373 char source[64];
374 char opts[64];
375
376 if (pipe(pipefd) < 0) {
377 ULOG_ERR("failed to get kernel pipe\n");
378 return -1;
379 }
380
381 snprintf(source, sizeof(source), "mountd(pid%u)", getpid());
382 snprintf(opts, sizeof(opts), "fd=%d,pgrp=%u,minproto=5,maxproto=5", pipefd[1], (unsigned) getpgrp());
383 mkdir(AUTOFS_MOUNT_PATH, 0555);
384 if (mount(source, AUTOFS_MOUNT_PATH, "autofs", 0, opts)) {
385 ULOG_ERR("unable to mount autofs on %s\n", AUTOFS_MOUNT_PATH);
386 close(pipefd[0]);
387 close(pipefd[1]);
388 return -1;
389 }
390 close(pipefd[1]);
391 fd_autofs_read.fd = pipefd[0];
392 fd_autofs_read.cb = autofs_read_handler;
393 uloop_fd_add(&fd_autofs_read, ULOOP_READ);
394
395 fd_autofs_write = open(AUTOFS_MOUNT_PATH, O_RDONLY);
396 if(fd_autofs_write < 0) {
397 autofs_umount();
398 ULOG_ERR("failed to open direcory\n");
399 return -1;
400 }
401
402 ioctl(fd_autofs_write, AUTOFS_IOC_PROTOVER, &kproto_version);
403 if (kproto_version != 5) {
404 ULOG_ERR("only kernel protocol version 5 is tested. You have %d.\n",
405 kproto_version);
406 exit(EXIT_FAILURE);
407 }
408 if (ioctl(fd_autofs_write, AUTOFS_IOC_SETTIMEOUT, &autofs_timeout))
409 ULOG_ERR("failed to set autofs timeout\n");
410
411 uloop_timeout_set(&autofs_expire_timer, AUTOFS_EXPIRE_TIMER);
412
413 fcntl(fd_autofs_write, F_SETFD, fcntl(fd_autofs_write, F_GETFD) | FD_CLOEXEC);
414 fcntl(fd_autofs_read.fd, F_SETFD, fcntl(fd_autofs_read.fd, F_GETFD) | FD_CLOEXEC);
415
416 return 0;
417 }
418
419 static void blockd_startup(struct uloop_timeout *t)
420 {
421 block("autofs", "start", NULL);
422 }
423
424 struct uloop_timeout startup = {
425 .cb = blockd_startup,
426 };
427
428 int main(int argc, char **argv)
429 {
430 ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
431 uloop_init();
432
433 autofs_mount();
434
435 conn.cb = ubus_connect_handler;
436 ubus_auto_connect(&conn);
437
438 uloop_timeout_set(&startup, 1000);
439
440 uloop_run();
441 uloop_done();
442
443 autofs_umount();
444
445 vlist_flush_all(&devices);
446
447 return 0;
448 }