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Sources/procd/inittab.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 #define _GNU_SOURCE
 16 #include <sys/types.h>
 17 #include <sys/stat.h>
 18 #include <sys/ioctl.h>
 19 
 20 #include <fcntl.h>
 21 #include <stdio.h>
 22 #include <stdlib.h>
 23 #include <unistd.h>
 24 #include <regex.h>
 25 #include <ctype.h>
 26 
 27 #include <libubox/utils.h>
 28 #include <libubox/list.h>
 29 
 30 #include "utils/utils.h"
 31 #include "procd.h"
 32 #include "rcS.h"
 33 
 34 #ifndef O_PATH
 35 #define O_PATH          010000000
 36 #endif
 37 
 38 #define TAG_ID          0
 39 #define TAG_RUNLVL      1
 40 #define TAG_ACTION      2
 41 #define TAG_PROCESS     3
 42 
 43 #define MAX_ARGS        8
 44 
 45 struct init_action;
 46 char *console = NULL;
 47 
 48 struct init_handler {
 49         const char *name;
 50         void (*cb) (struct init_action *a);
 51         int multi;
 52 };
 53 
 54 struct init_action {
 55         struct list_head list;
 56 
 57         char *id;
 58         char *argv[MAX_ARGS];
 59         char *line;
 60 
 61         struct init_handler *handler;
 62         struct uloop_process proc;
 63 
 64         int respawn;
 65         struct uloop_timeout tout;
 66 };
 67 
 68 static const char *tab = "/etc/inittab";
 69 static char *ask = "/sbin/askfirst";
 70 
 71 static LIST_HEAD(actions);
 72 
 73 static int dev_exist(const char *dev)
 74 {
 75         int dfd, fd;
 76 
 77         dfd = open("/dev", O_PATH|O_DIRECTORY);
 78 
 79         if (dfd < 0)
 80                 return 0;
 81 
 82         fd = openat(dfd, dev, O_RDONLY);
 83         close(dfd);
 84 
 85         if (fd < 0)
 86                 return 0;
 87 
 88         close(fd);
 89         return 1;
 90 }
 91 
 92 static void fork_worker(struct init_action *a)
 93 {
 94         pid_t p;
 95 
 96         a->proc.pid = fork();
 97         if (!a->proc.pid) {
 98                 p = setsid();
 99 
100                 if (patch_stdio(a->id))
101                         ERROR("Failed to setup i/o redirection\n");
102 
103                 ioctl(STDIN_FILENO, TIOCSCTTY, 1);
104                 tcsetpgrp(STDIN_FILENO, p);
105 
106                 execvp(a->argv[0], a->argv);
107                 ERROR("Failed to execute %s: %m\n", a->argv[0]);
108                 exit(-1);
109         }
110 
111         if (a->proc.pid > 0) {
112                 DEBUG(4, "Launched new %s action, pid=%d\n",
113                                         a->handler->name,
114                                         (int) a->proc.pid);
115                 uloop_process_add(&a->proc);
116         }
117 }
118 
119 static void child_exit(struct uloop_process *proc, int ret)
120 {
121         struct init_action *a = container_of(proc, struct init_action, proc);
122 
123         DEBUG(4, "pid:%d, exitcode:%d\n", proc->pid, ret);
124         proc->pid = 0;
125 
126         if (a->respawn < 0)
127                 return;
128 
129         if (!dev_exist(a->id)) {
130                 DEBUG(4, "Skipping respawn: device '%s' does not exist anymore\n", a->id);
131                 return;
132         }
133 
134         uloop_timeout_set(&a->tout, a->respawn);
135 }
136 
137 static void respawn(struct uloop_timeout *tout)
138 {
139         struct init_action *a = container_of(tout, struct init_action, tout);
140         if (!a->proc.pid)
141                 fork_worker(a);
142 }
143 
144 static void rcdone(struct runqueue *q)
145 {
146         procd_state_next();
147 }
148 
149 static void runrc(struct init_action *a)
150 {
151         if (!a->argv[1] || !a->argv[2]) {
152                 ERROR("valid format is rcS <S|K> <param>\n");
153                 return;
154         }
155 
156         /* proceed even if no init or shutdown scripts run */
157         if (rcS(a->argv[1], a->argv[2], rcdone))
158                 rcdone(NULL);
159 }
160 
161 static void askfirst(struct init_action *a)
162 {
163         int i;
164 
165         if (!dev_exist(a->id) || (console && !strcmp(console, a->id))) {
166                 DEBUG(4, "Skipping %s\n", a->id);
167                 return;
168         }
169 
170         a->tout.cb = respawn;
171         /* shift arguments only if not yet done */
172         if (a->argv[0] != ask) {
173                 for (i = MAX_ARGS - 1; i >= 1; i--)
174                         a->argv[i] = a->argv[i - 1];
175                 a->argv[0] = ask;
176         }
177         a->respawn = 500;
178 
179         a->proc.cb = child_exit;
180         if (!a->proc.pid)
181                 fork_worker(a);
182 }
183 
184 static void askconsole(struct init_action *a)
185 {
186         char line[256], *tty, *split;
187         int i;
188 
189         /* First, try console= on the kernel command line,
190          * then fallback to /sys/class/tty/console/active,
191          * which should work when linux,stdout-path (or equivalent)
192          * is in the device tree
193          */
194         tty = get_cmdline_val("console", line, sizeof(line));
195         if (tty == NULL ||
196             get_cmdline_val_offset("console", line, sizeof(line), 1)) {
197                 if (dev_exist("console"))
198                         tty = "console";
199                 else
200                         tty = get_active_console(line, sizeof(line));
201         }
202         if (tty != NULL) {
203                 split = strchr(tty, ',');
204                 if (split != NULL)
205                         *split = '\0';
206 
207                 if (!dev_exist(tty)) {
208                         DEBUG(4, "skipping %s\n", tty);
209                         return;
210                 }
211 
212                 console = strdup(tty);
213                 a->id = strdup(tty);
214         }
215         else {
216                 console = NULL;
217                 a->id = NULL;
218         }
219 
220         a->tout.cb = respawn;
221         /* shift arguments only if not yet done */
222         if (a->argv[0] != ask) {
223                 for (i = MAX_ARGS - 1; i >= 1; i--)
224                         a->argv[i] = a->argv[i - 1];
225                 a->argv[0] = ask;
226         }
227         a->respawn = 500;
228 
229         a->proc.cb = child_exit;
230         if (!a->proc.pid)
231                 fork_worker(a);
232 }
233 
234 static void rcrespawn(struct init_action *a)
235 {
236         a->tout.cb = respawn;
237         a->respawn = 500;
238 
239         a->proc.cb = child_exit;
240         if (!a->proc.pid)
241                 fork_worker(a);
242 }
243 
244 static struct init_handler handlers[] = {
245         {
246                 .name = "sysinit",
247                 .cb = runrc,
248         }, {
249                 .name = "shutdown",
250                 .cb = runrc,
251         }, {
252                 .name = "askfirst",
253                 .cb = askfirst,
254                 .multi = 1,
255         }, {
256                 .name = "askconsole",
257                 .cb = askconsole,
258                 .multi = 1,
259         }, {
260                 .name = "respawn",
261                 .cb = rcrespawn,
262                 .multi = 1,
263         }, {
264                 .name = "askconsolelate",
265                 .cb = askconsole,
266                 .multi = 1,
267         }, {
268                 .name = "respawnlate",
269                 .cb = rcrespawn,
270                 .multi = 1,
271         }
272 };
273 
274 static int add_action(struct init_action *a, const char *name)
275 {
276         int i;
277 
278         for (i = 0; i < ARRAY_SIZE(handlers); i++)
279                 if (!strcmp(handlers[i].name, name)) {
280                         a->handler = &handlers[i];
281                         list_add_tail(&a->list, &actions);
282                         return 0;
283                 }
284         ERROR("Unknown init handler %s\n", name);
285         return -1;
286 }
287 
288 void procd_inittab_run(const char *handler)
289 {
290         struct init_action *a;
291 
292         list_for_each_entry(a, &actions, list)
293                 if (!strcmp(a->handler->name, handler)) {
294                         a->handler->cb(a);
295                         if (!a->handler->multi)
296                                 break;
297                 }
298 }
299 
300 void procd_inittab_kill(void)
301 {
302         struct init_action *a;
303 
304         list_for_each_entry(a, &actions, list) {
305                 a->respawn = -1;
306                 if (a->proc.pid)
307                         kill(a->proc.pid, SIGKILL);
308         }
309 }
310 
311 void procd_inittab(void)
312 {
313 #define LINE_LEN        128
314         FILE *fp = fopen(tab, "r");
315         struct init_action *a;
316         regex_t pat_inittab;
317         regmatch_t matches[5];
318         char *line;
319 
320         if (!fp) {
321                 ERROR("Failed to open %s: %m\n", tab);
322                 return;
323         }
324 
325         regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):(.*)", REG_EXTENDED);
326         line = malloc(LINE_LEN);
327         a = calloc(1, sizeof(struct init_action));
328 
329         while (fgets(line, LINE_LEN, fp)) {
330                 char *tags[TAG_PROCESS + 1];
331                 char *tok;
332                 int i;
333                 int len = strlen(line);
334 
335                 while (isspace(line[len - 1]))
336                         len--;
337                 line[len] = 0;
338 
339                 if (*line == '#')
340                         continue;
341 
342                 if (regexec(&pat_inittab, line, 5, matches, 0))
343                         continue;
344 
345                 DEBUG(4, "Parsing inittab - %s\n", line);
346 
347                 for (i = TAG_ID; i <= TAG_PROCESS; i++) {
348                         line[matches[i].rm_eo] = '\0';
349                         tags[i] = &line[matches[i + 1].rm_so];
350                 };
351 
352                 tok = strtok(tags[TAG_PROCESS], " ");
353                 for (i = 0; i < (MAX_ARGS - 1) && tok; i++) {
354                         a->argv[i] = tok;
355                         tok = strtok(NULL, " ");
356                 }
357                 a->argv[i] = NULL;
358                 a->id = tags[TAG_ID];
359                 a->line = line;
360 
361                 if (add_action(a, tags[TAG_ACTION]))
362                         continue;
363                 line = malloc(LINE_LEN);
364                 a = calloc(1, sizeof(struct init_action));
365         }
366 
367         fclose(fp);
368         free(line);
369         free(a);
370         regfree(&pat_inittab);
371 }
372 

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