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Sources/procd/plug/hotplug.c

  1 /*
  2  * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
  3  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU Lesser General Public License version 2.1
  7  * as published by the Free Software Foundation
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  */
 14 
 15 #include <sys/stat.h>
 16 #include <sys/socket.h>
 17 #include <sys/types.h>
 18 #include <sys/sysmacros.h>
 19 
 20 #include <linux/types.h>
 21 #include <linux/netlink.h>
 22 
 23 #include <libubox/blobmsg_json.h>
 24 #include <libubox/json_script.h>
 25 #include <libubox/uloop.h>
 26 #include <libubox/utils.h>
 27 #include <json-c/json.h>
 28 
 29 #include <errno.h>
 30 #include <fcntl.h>
 31 #include <unistd.h>
 32 #include <stdlib.h>
 33 #include <libgen.h>
 34 #include <grp.h>
 35 
 36 #include "../procd.h"
 37 
 38 #include "hotplug.h"
 39 
 40 #define HOTPLUG_WAIT    500
 41 
 42 struct cmd_handler;
 43 struct cmd_queue {
 44         struct list_head list;
 45 
 46         struct blob_attr *msg;
 47         struct blob_attr *data;
 48         int timeout;
 49 
 50         void (*handler)(struct blob_attr *msg, struct blob_attr *data);
 51         void (*start)(struct blob_attr *msg, struct blob_attr *data);
 52         void (*complete)(struct blob_attr *msg, struct blob_attr *data, int ret);
 53 };
 54 
 55 struct button_timeout {
 56         struct list_head list;
 57         struct uloop_timeout timeout;
 58         char *name;
 59         int seen;
 60         struct blob_attr *data;
 61 };
 62 
 63 static LIST_HEAD(cmd_queue);
 64 static LIST_HEAD(button_timer);
 65 static struct uloop_process queue_proc;
 66 static struct uloop_timeout last_event;
 67 static struct blob_buf b, button_buf;
 68 static char *rule_file;
 69 static struct blob_buf script;
 70 static struct cmd_queue *current;
 71 
 72 static void queue_add(struct cmd_handler *h, struct blob_attr *msg, struct blob_attr *data);
 73 static void handle_button_complete(struct blob_attr *msg, struct blob_attr *data, int ret);
 74 
 75 static void button_free(struct button_timeout *b)
 76 {
 77         uloop_timeout_cancel(&b->timeout);
 78         list_del(&b->list);
 79         free(b->data);
 80         free(b->name);
 81         free(b);
 82 }
 83 
 84 static void button_timeout_remove(char *button)
 85 {
 86         struct button_timeout *b, *c;
 87 
 88         if (!list_empty(&button_timer)) list_for_each_entry_safe(b, c, &button_timer, list) {
 89                 if (!strcmp(b->name, button))
 90                         button_free(b);
 91         }
 92 }
 93 
 94 static char *hotplug_msg_find_var(struct blob_attr *msg, const char *name)
 95 {
 96         struct blob_attr *cur;
 97         int rem;
 98 
 99         blobmsg_for_each_attr(cur, msg, rem) {
100                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
101                         continue;
102 
103                 if (strcmp(blobmsg_name(cur), name) != 0)
104                         continue;
105 
106                 return blobmsg_data(cur);
107         }
108 
109         return NULL;
110 }
111 
112 static void chgrp_error(const char *group, const char *target, const char *failed)
113 {
114         ERROR("cannot set group %s for %s (%s: %d)\n",
115                group, target, failed, errno);
116 }
117 
118 static void chgrp_target(struct blob_attr *bgroup, struct blob_attr *btarget)
119 {
120         int ret = 0;
121         struct group *g = NULL;
122         const char *group = blobmsg_get_string(bgroup);
123         const char *target = blobmsg_get_string(btarget);
124 
125         errno = 0;
126 
127         g = getgrnam(group);
128         if (!g)
129                 return chgrp_error(group, target, "getgrnam");
130 
131         ret = chown(target, 0, g->gr_gid);
132         if (ret < 0)
133                 return chgrp_error(group, target, "chown");
134 }
135 
136 static void handle_makedev(struct blob_attr *msg, struct blob_attr *data)
137 {
138         unsigned int oldumask = umask(0);
139         static struct blobmsg_policy mkdev_policy[3] = {
140                 { .type = BLOBMSG_TYPE_STRING },
141                 { .type = BLOBMSG_TYPE_STRING },
142                 { .type = BLOBMSG_TYPE_STRING },
143         };
144         struct blob_attr *tb[3];
145         char *minor = hotplug_msg_find_var(msg, "MINOR");
146         char *major = hotplug_msg_find_var(msg, "MAJOR");
147         char *subsystem = hotplug_msg_find_var(msg, "SUBSYSTEM");
148 
149         blobmsg_parse_array(mkdev_policy, 3, tb, blobmsg_data(data), blobmsg_data_len(data));
150         if (tb[0] && tb[1] && minor && major && subsystem) {
151                 mode_t m = S_IFCHR;
152                 char *d = strdup(blobmsg_get_string(tb[0]));
153 
154                 d = dirname(d);
155                 mkdir_p(d, 0755);
156                 free(d);
157 
158                 if (!strcmp(subsystem, "block"))
159                         m = S_IFBLK;
160                 mknod(blobmsg_get_string(tb[0]),
161                                 m | strtoul(blobmsg_data(tb[1]), NULL, 8),
162                                 makedev(atoi(major), atoi(minor)));
163                 if (tb[2])
164                         chgrp_target(tb[2], tb[0]);
165         }
166         umask(oldumask);
167 }
168 
169 static void handle_rm(struct blob_attr *msg, struct blob_attr *data)
170 {
171         static struct blobmsg_policy rm_policy = {
172                 .type = BLOBMSG_TYPE_STRING,
173         };
174         struct blob_attr *tb;
175 
176         blobmsg_parse_array(&rm_policy, 1, &tb, blobmsg_data(data), blobmsg_data_len(data));
177         if (tb)
178                 unlink(blobmsg_data(tb));
179 }
180 
181 static void handle_exec(struct blob_attr *msg, struct blob_attr *data)
182 {
183         char *argv[8];
184         struct blob_attr *cur;
185         int rem, fd;
186         int i = 0;
187 
188         blobmsg_for_each_attr(cur, msg, rem)
189                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
190 
191         blobmsg_for_each_attr(cur, data, rem) {
192                 argv[i] = blobmsg_data(cur);
193                 i++;
194                 if (i == 7)
195                         break;
196         }
197 
198         if (debug < 3) {
199                 fd = open("/dev/null", O_RDWR);
200                 if (fd > -1) {
201                         dup2(fd, STDIN_FILENO);
202                         dup2(fd, STDOUT_FILENO);
203                         dup2(fd, STDERR_FILENO);
204                         if (fd > STDERR_FILENO)
205                                 close(fd);
206                 }
207         }
208 
209         if (i > 0) {
210                 argv[i] = NULL;
211                 execvp(argv[0], &argv[0]);
212         }
213         exit(EXIT_FAILURE);
214 }
215 
216 static void handle_button_start(struct blob_attr *msg, struct blob_attr *data)
217 {
218         char *button = hotplug_msg_find_var(msg, "BUTTON");
219 
220         if (button)
221                 button_timeout_remove(button);
222 }
223 
224 static void handle_firmware(struct blob_attr *msg, struct blob_attr *data)
225 {
226         char *dir = blobmsg_get_string(blobmsg_data(data));
227         char *file = hotplug_msg_find_var(msg, "FIRMWARE");
228         char *dev = hotplug_msg_find_var(msg, "DEVPATH");
229         struct stat s = { 0 };
230         char *path, loadpath[256], syspath[256];
231         int fw, src, load, len;
232         static char buf[4096];
233 
234         P_DEBUG(2, "Firmware request for %s/%s\n", dir, file);
235 
236         if (!file || !dir || !dev) {
237                 ERROR("Request for unknown firmware %s/%s\n", dir, file);
238                 exit(EXIT_FAILURE);
239         }
240 
241         path = alloca(strlen(dir) + strlen(file) + 2);
242         sprintf(path, "%s/%s", dir, file);
243 
244         if (stat(path, &s)) {
245                 ERROR("Could not find firmware %s: %m\n", path);
246                 src = -1;
247                 s.st_size = 0;
248                 goto send_to_kernel;
249         }
250 
251         src = open(path, O_RDONLY);
252         if (src < 0) {
253                 ERROR("Failed to open %s: %m\n", path);
254                 s.st_size = 0;
255                 goto send_to_kernel;
256         }
257 
258 send_to_kernel:
259         snprintf(loadpath, sizeof(loadpath), "/sys/%s/loading", dev);
260         load = open(loadpath, O_WRONLY);
261         if (!load) {
262                 ERROR("Failed to open %s: %m\n", loadpath);
263                 exit(EXIT_FAILURE);
264         }
265         if (write(load, "1", 1) == -1) {
266                 ERROR("Failed to write to %s: %m\n", loadpath);
267                 exit(EXIT_FAILURE);
268         }
269         close(load);
270 
271         snprintf(syspath, sizeof(syspath), "/sys/%s/data", dev);
272         fw = open(syspath, O_WRONLY);
273         if (fw < 0) {
274                 ERROR("Failed to open %s: %m\n", syspath);
275                 exit(EXIT_FAILURE);
276         }
277 
278         len = s.st_size;
279         while (len) {
280                 len = read(src, buf, sizeof(buf));
281                 if (len <= 0)
282                         break;
283 
284                 if (write(fw, buf, len) == -1) {
285                         ERROR("failed to write firmware file %s/%s to %s: %m\n", dir, file, dev);
286                         break;
287                 }
288         }
289 
290         if (src >= 0)
291                 close(src);
292         close(fw);
293 
294         load = open(loadpath, O_WRONLY);
295         if (write(load, "", 1) == -1)
296                 ERROR("failed to write to %s: %m\n", loadpath);
297         close(load);
298 
299         P_DEBUG(2, "Done loading %s\n", path);
300 
301         exit(EXIT_FAILURE);
302 }
303 
304 static void handle_start_console(struct blob_attr *msg, struct blob_attr *data)
305 {
306         char *dev = blobmsg_get_string(blobmsg_data(data));
307 
308         P_DEBUG(2, "Start console request for %s\n", dev);
309 
310         procd_inittab_run("respawn");
311         procd_inittab_run("askfirst");
312 
313         P_DEBUG(2, "Done starting console for %s\n", dev);
314 
315         exit(EXIT_FAILURE);
316 }
317 
318 enum {
319         HANDLER_MKDEV = 0,
320         HANDLER_RM,
321         HANDLER_EXEC,
322         HANDLER_BUTTON,
323         HANDLER_FW,
324         HANDLER_START_CONSOLE,
325 };
326 
327 static struct cmd_handler {
328         char *name;
329         int atomic;
330         void (*handler)(struct blob_attr *msg, struct blob_attr *data);
331         void (*start)(struct blob_attr *msg, struct blob_attr *data);
332         void (*complete)(struct blob_attr *msg, struct blob_attr *data, int ret);
333 } handlers[] = {
334         [HANDLER_MKDEV] = {
335                 .name = "makedev",
336                 .atomic = 1,
337                 .handler = handle_makedev,
338         },
339         [HANDLER_RM] = {
340                 .name = "rm",
341                 .atomic = 1,
342                 .handler = handle_rm,
343         },
344         [HANDLER_EXEC] = {
345                 .name = "exec",
346                 .handler = handle_exec,
347         },
348         [HANDLER_BUTTON] = {
349                 .name = "button",
350                 .handler = handle_exec,
351                 .start = handle_button_start,
352                 .complete = handle_button_complete,
353         },
354         [HANDLER_FW] = {
355                 .name = "load-firmware",
356                 .handler = handle_firmware,
357         },
358         [HANDLER_START_CONSOLE] = {
359                 .name = "start-console",
360                 .handler = handle_start_console,
361         },
362 };
363 
364 static void queue_next(void)
365 {
366         struct cmd_queue *c;
367 
368         if (queue_proc.pending || list_empty(&cmd_queue))
369                 return;
370 
371         c = list_first_entry(&cmd_queue, struct cmd_queue, list);
372 
373         queue_proc.pid = fork();
374         if (!queue_proc.pid) {
375                 uloop_done();
376                 c->handler(c->msg, c->data);
377                 exit(0);
378         }
379         if (c->start)
380                 c->start(c->msg, c->data);
381         list_del(&c->list);
382         if (c->complete)
383                 current = c;
384         else
385                 free(c);
386         if (queue_proc.pid <= 0) {
387                 queue_next();
388                 return;
389         }
390 
391         uloop_process_add(&queue_proc);
392 
393         P_DEBUG(4, "Launched hotplug exec instance, pid=%d\n", (int) queue_proc.pid);
394 }
395 
396 static void queue_proc_cb(struct uloop_process *c, int ret)
397 {
398         P_DEBUG(4, "Finished hotplug exec instance, pid=%d\n", (int) c->pid);
399 
400         if (current) {
401                 current->complete(current->msg, current->data, ret);
402                 free(current);
403                 current = NULL;
404         }
405         queue_next();
406 }
407 
408 static void queue_add(struct cmd_handler *h, struct blob_attr *msg, struct blob_attr *data)
409 {
410         struct cmd_queue *c = NULL;
411         struct blob_attr *_msg, *_data;
412 
413         c = calloc_a(sizeof(struct cmd_queue),
414                 &_msg, blob_pad_len(msg),
415                 &_data, blob_pad_len(data),
416                 NULL);
417 
418         if (!c)
419                 return;
420 
421         c->msg = _msg;
422         c->data = _data;
423 
424         memcpy(c->msg, msg, blob_pad_len(msg));
425         memcpy(c->data, data, blob_pad_len(data));
426         c->handler = h->handler;
427         c->complete = h->complete;
428         c->start = h->start;
429         list_add_tail(&c->list, &cmd_queue);
430         queue_next();
431 }
432 
433 static void handle_button_timeout(struct uloop_timeout *t)
434 {
435         struct button_timeout *b;
436         char seen[16];
437 
438         b = container_of(t, struct button_timeout, timeout);
439         blob_buf_init(&button_buf, 0);
440         blobmsg_add_string(&button_buf, "BUTTON", b->name);
441         blobmsg_add_string(&button_buf, "ACTION", "timeout");
442         snprintf(seen, sizeof(seen), "%d", b->seen);
443         blobmsg_add_string(&button_buf, "SEEN", seen);
444         queue_add(&handlers[HANDLER_EXEC], button_buf.head, b->data);
445         button_free(b);
446 }
447 
448 static void handle_button_complete(struct blob_attr *msg, struct blob_attr *data, int ret)
449 {
450         char *name = hotplug_msg_find_var(msg, "BUTTON");
451         struct button_timeout *b;
452         int timeout = ret >> 8;
453 
454         if (!timeout)
455                 return;
456 
457         if (!name)
458                 return;
459 
460         b = calloc(1, sizeof(*b));
461         if (!b)
462                 return;
463 
464         b->data = malloc(blob_pad_len(data));
465         b->name = strdup(name);
466         b->seen = timeout;
467 
468         memcpy(b->data, data, blob_pad_len(data));
469         b->timeout.cb = handle_button_timeout;
470 
471         uloop_timeout_set(&b->timeout, timeout * 1000);
472         list_add(&b->list, &button_timer);
473 }
474 
475 static const char* rule_handle_var(struct json_script_ctx *ctx, const char *name, struct blob_attr *vars)
476 {
477         const char *str, *sep;
478 
479         if (!strcmp(name, "DEVICENAME") || !strcmp(name, "DEVNAME")) {
480                 str = json_script_find_var(ctx, vars, "DEVPATH");
481                 if (!str)
482                         return NULL;
483 
484                 sep = strrchr(str, '/');
485                 if (sep)
486                         return sep + 1;
487 
488                 return str;
489         }
490 
491         return NULL;
492 }
493 
494 static struct json_script_file *
495 rule_handle_file(struct json_script_ctx *ctx, const char *name)
496 {
497         json_object *obj;
498 
499         obj = json_object_from_file((char*)name);
500         if (!obj)
501                 return NULL;
502 
503         blob_buf_init(&script, 0);
504         blobmsg_add_json_element(&script, "", obj);
505 
506         return json_script_file_from_blobmsg(name, blob_data(script.head), blob_len(script.head));
507 }
508 
509 static void rule_handle_command(struct json_script_ctx *ctx, const char *name,
510                                 struct blob_attr *data, struct blob_attr *vars)
511 {
512         struct blob_attr *cur;
513         int rem, i;
514 
515         if (debug > 3) {
516                 P_DEBUG(4, "Command: %s\n", name);
517                 blobmsg_for_each_attr(cur, data, rem)
518                         P_DEBUG(4, " %s\n", (char *) blobmsg_data(cur));
519 
520                 P_DEBUG(4, "Message:\n");
521                 blobmsg_for_each_attr(cur, vars, rem)
522                         P_DEBUG(4, " %s=%s\n", blobmsg_name(cur), (char *) blobmsg_data(cur));
523         }
524 
525         for (i = 0; i < ARRAY_SIZE(handlers); i++)
526                 if (!strcmp(handlers[i].name, name)) {
527                         if (handlers[i].atomic)
528                                 handlers[i].handler(vars, data);
529                         else
530                                 queue_add(&handlers[i], vars, data);
531                         break;
532                 }
533 
534         if (last_event.cb)
535                 uloop_timeout_set(&last_event, HOTPLUG_WAIT);
536 }
537 
538 static void rule_handle_error(struct json_script_ctx *ctx, const char *msg,
539                                 struct blob_attr *context)
540 {
541         char *s;
542 
543         s = blobmsg_format_json(context, false);
544         ERROR("ERROR: %s in block: %s\n", msg, s);
545         free(s);
546 }
547 
548 static struct json_script_ctx jctx = {
549         .handle_var = rule_handle_var,
550         .handle_error = rule_handle_error,
551         .handle_command = rule_handle_command,
552         .handle_file = rule_handle_file,
553 };
554 
555 static void hotplug_handler_debug(struct blob_attr *data)
556 {
557         char *str;
558 
559         if (debug < 3)
560                 return;
561 
562         str = blobmsg_format_json(data, true);
563         P_DEBUG(3, "%s\n", str);
564         free(str);
565 }
566 
567 static void hotplug_handler(struct uloop_fd *u, unsigned int ev)
568 {
569         int i = 0;
570         static char buf[4096];
571         int len = recv(u->fd, buf, sizeof(buf) - 1, MSG_DONTWAIT);
572         void *index;
573         if (len < 1)
574                 return;
575 
576         buf[len] = '\0';
577 
578         blob_buf_init(&b, 0);
579         index = blobmsg_open_table(&b, NULL);
580         while (i < len) {
581                 int l = strlen(buf + i) + 1;
582                 char *e = strstr(&buf[i], "=");
583 
584                 if (e) {
585                         *e = '\0';
586                         blobmsg_add_string(&b, &buf[i], &e[1]);
587                 }
588                 i += l;
589         }
590         blobmsg_close_table(&b, index);
591         hotplug_handler_debug(b.head);
592         json_script_run(&jctx, rule_file, blob_data(b.head));
593 }
594 
595 static struct uloop_fd hotplug_fd = {
596         .cb = hotplug_handler,
597 };
598 
599 void hotplug_last_event(uloop_timeout_handler handler)
600 {
601         last_event.cb = handler;
602         if (handler)
603                 uloop_timeout_set(&last_event, HOTPLUG_WAIT);
604         else
605                 uloop_timeout_cancel(&last_event);
606 }
607 
608 void hotplug(char *rules)
609 {
610         struct sockaddr_nl nls = {};
611         int nlbufsize = 512 * 1024;
612 
613         rule_file = strdup(rules);
614         nls.nl_family = AF_NETLINK;
615         nls.nl_pid = 0;
616         nls.nl_groups = -1;
617 
618         if ((hotplug_fd.fd = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT)) == -1) {
619                 ERROR("Failed to open hotplug socket: %m\n");
620                 exit(1);
621         }
622         if (bind(hotplug_fd.fd, (void *)&nls, sizeof(struct sockaddr_nl))) {
623                 ERROR("Failed to bind hotplug socket: %m\n");
624                 exit(1);
625         }
626 
627         if (setsockopt(hotplug_fd.fd, SOL_SOCKET, SO_RCVBUFFORCE, &nlbufsize, sizeof(nlbufsize)))
628                 ERROR("Failed to resize receive buffer: %m\n");
629 
630         json_script_init(&jctx);
631         queue_proc.cb = queue_proc_cb;
632         uloop_fd_add(&hotplug_fd, ULOOP_READ);
633 }
634 
635 int hotplug_run(char *rules)
636 {
637         uloop_init();
638         hotplug(rules);
639         uloop_run();
640 
641         return 0;
642 }
643 
644 void hotplug_shutdown(void)
645 {
646         uloop_fd_delete(&hotplug_fd);
647         close(hotplug_fd.fd);
648 }
649 

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