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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                 if (dev_exist("console"))
197                         tty = "console";
198                 else
199                         tty = get_active_console(line, sizeof(line));
200         }
201         if (tty != NULL) {
202                 split = strchr(tty, ',');
203                 if (split != NULL)
204                         *split = '\0';
205 
206                 if (!dev_exist(tty)) {
207                         DEBUG(4, "skipping %s\n", tty);
208                         return;
209                 }
210 
211                 console = strdup(tty);
212                 a->id = strdup(tty);
213         }
214         else {
215                 console = NULL;
216                 a->id = NULL;
217         }
218 
219         a->tout.cb = respawn;
220         /* shift arguments only if not yet done */
221         if (a->argv[0] != ask) {
222                 for (i = MAX_ARGS - 1; i >= 1; i--)
223                         a->argv[i] = a->argv[i - 1];
224                 a->argv[0] = ask;
225         }
226         a->respawn = 500;
227 
228         a->proc.cb = child_exit;
229         if (!a->proc.pid)
230                 fork_worker(a);
231 }
232 
233 static void rcrespawn(struct init_action *a)
234 {
235         a->tout.cb = respawn;
236         a->respawn = 500;
237 
238         a->proc.cb = child_exit;
239         if (!a->proc.pid)
240                 fork_worker(a);
241 }
242 
243 static struct init_handler handlers[] = {
244         {
245                 .name = "sysinit",
246                 .cb = runrc,
247         }, {
248                 .name = "shutdown",
249                 .cb = runrc,
250         }, {
251                 .name = "askfirst",
252                 .cb = askfirst,
253                 .multi = 1,
254         }, {
255                 .name = "askconsole",
256                 .cb = askconsole,
257                 .multi = 1,
258         }, {
259                 .name = "respawn",
260                 .cb = rcrespawn,
261                 .multi = 1,
262         }, {
263                 .name = "askconsolelate",
264                 .cb = askconsole,
265                 .multi = 1,
266         }, {
267                 .name = "respawnlate",
268                 .cb = rcrespawn,
269                 .multi = 1,
270         }
271 };
272 
273 static int add_action(struct init_action *a, const char *name)
274 {
275         int i;
276 
277         for (i = 0; i < ARRAY_SIZE(handlers); i++)
278                 if (!strcmp(handlers[i].name, name)) {
279                         a->handler = &handlers[i];
280                         list_add_tail(&a->list, &actions);
281                         return 0;
282                 }
283         ERROR("Unknown init handler %s\n", name);
284         return -1;
285 }
286 
287 void procd_inittab_run(const char *handler)
288 {
289         struct init_action *a;
290 
291         list_for_each_entry(a, &actions, list)
292                 if (!strcmp(a->handler->name, handler)) {
293                         a->handler->cb(a);
294                         if (!a->handler->multi)
295                                 break;
296                 }
297 }
298 
299 void procd_inittab_kill(void)
300 {
301         struct init_action *a;
302 
303         list_for_each_entry(a, &actions, list) {
304                 a->respawn = -1;
305                 if (a->proc.pid)
306                         kill(a->proc.pid, SIGKILL);
307         }
308 }
309 
310 void procd_inittab(void)
311 {
312 #define LINE_LEN        128
313         FILE *fp = fopen(tab, "r");
314         struct init_action *a;
315         regex_t pat_inittab;
316         regmatch_t matches[5];
317         char *line;
318 
319         if (!fp) {
320                 ERROR("Failed to open %s: %m\n", tab);
321                 return;
322         }
323 
324         regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):(.*)", REG_EXTENDED);
325         line = malloc(LINE_LEN);
326         a = calloc(1, sizeof(struct init_action));
327 
328         while (fgets(line, LINE_LEN, fp)) {
329                 char *tags[TAG_PROCESS + 1];
330                 char *tok;
331                 int i;
332                 int len = strlen(line);
333 
334                 while (isspace(line[len - 1]))
335                         len--;
336                 line[len] = 0;
337 
338                 if (*line == '#')
339                         continue;
340 
341                 if (regexec(&pat_inittab, line, 5, matches, 0))
342                         continue;
343 
344                 DEBUG(4, "Parsing inittab - %s\n", line);
345 
346                 for (i = TAG_ID; i <= TAG_PROCESS; i++) {
347                         line[matches[i].rm_eo] = '\0';
348                         tags[i] = &line[matches[i + 1].rm_so];
349                 };
350 
351                 tok = strtok(tags[TAG_PROCESS], " ");
352                 for (i = 0; i < (MAX_ARGS - 1) && tok; i++) {
353                         a->argv[i] = tok;
354                         tok = strtok(NULL, " ");
355                 }
356                 a->argv[i] = NULL;
357                 a->id = tags[TAG_ID];
358                 a->line = line;
359 
360                 if (add_action(a, tags[TAG_ACTION]))
361                         continue;
362                 line = malloc(LINE_LEN);
363                 a = calloc(1, sizeof(struct init_action));
364         }
365 
366         fclose(fp);
367         free(line);
368         free(a);
369         regfree(&pat_inittab);
370 }
371 

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