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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 (!dev_exist(a->id)) {
127                 DEBUG(4, "Skipping respawn: device '%s' does not exist anymore\n", a->id);
128                 return;
129         }
130 
131         uloop_timeout_set(&a->tout, a->respawn);
132 }
133 
134 static void respawn(struct uloop_timeout *tout)
135 {
136         struct init_action *a = container_of(tout, struct init_action, tout);
137         if (!a->proc.pid)
138                 fork_worker(a);
139 }
140 
141 static void rcdone(struct runqueue *q)
142 {
143         procd_state_next();
144 }
145 
146 static void runrc(struct init_action *a)
147 {
148         if (!a->argv[1] || !a->argv[2]) {
149                 ERROR("valid format is rcS <S|K> <param>\n");
150                 return;
151         }
152 
153         /* proceed even if no init or shutdown scripts run */
154         if (rcS(a->argv[1], a->argv[2], rcdone))
155                 rcdone(NULL);
156 }
157 
158 static void askfirst(struct init_action *a)
159 {
160         int i;
161 
162         if (!dev_exist(a->id) || (console && !strcmp(console, a->id))) {
163                 DEBUG(4, "Skipping %s\n", a->id);
164                 return;
165         }
166 
167         a->tout.cb = respawn;
168         /* shift arguments only if not yet done */
169         if (a->argv[0] != ask) {
170                 for (i = MAX_ARGS - 1; i >= 1; i--)
171                         a->argv[i] = a->argv[i - 1];
172                 a->argv[0] = ask;
173         }
174         a->respawn = 500;
175 
176         a->proc.cb = child_exit;
177         if (!a->proc.pid)
178                 fork_worker(a);
179 }
180 
181 static void askconsole(struct init_action *a)
182 {
183         char line[256], *tty, *split;
184         int i;
185 
186         /* First, try console= on the kernel command line,
187          * then fallback to /sys/class/tty/console/active,
188          * which should work when linux,stdout-path (or equivalent)
189          * is in the device tree
190          */
191         tty = get_cmdline_val("console", line, sizeof(line));
192         if (tty == NULL) {
193                 if (dev_exist("console"))
194                         tty = "console";
195                 else
196                         tty = get_active_console(line, sizeof(line));
197         }
198         if (tty != NULL) {
199                 split = strchr(tty, ',');
200                 if (split != NULL)
201                         *split = '\0';
202 
203                 if (!dev_exist(tty)) {
204                         DEBUG(4, "skipping %s\n", tty);
205                         return;
206                 }
207 
208                 console = strdup(tty);
209                 a->id = strdup(tty);
210         }
211         else {
212                 console = NULL;
213                 a->id = NULL;
214         }
215 
216         a->tout.cb = respawn;
217         /* shift arguments only if not yet done */
218         if (a->argv[0] != ask) {
219                 for (i = MAX_ARGS - 1; i >= 1; i--)
220                         a->argv[i] = a->argv[i - 1];
221                 a->argv[0] = ask;
222         }
223         a->respawn = 500;
224 
225         a->proc.cb = child_exit;
226         if (!a->proc.pid)
227                 fork_worker(a);
228 }
229 
230 static void rcrespawn(struct init_action *a)
231 {
232         a->tout.cb = respawn;
233         a->respawn = 500;
234 
235         a->proc.cb = child_exit;
236         if (!a->proc.pid)
237                 fork_worker(a);
238 }
239 
240 static struct init_handler handlers[] = {
241         {
242                 .name = "sysinit",
243                 .cb = runrc,
244         }, {
245                 .name = "shutdown",
246                 .cb = runrc,
247         }, {
248                 .name = "askfirst",
249                 .cb = askfirst,
250                 .multi = 1,
251         }, {
252                 .name = "askconsole",
253                 .cb = askconsole,
254                 .multi = 1,
255         }, {
256                 .name = "respawn",
257                 .cb = rcrespawn,
258                 .multi = 1,
259         }, {
260                 .name = "askconsolelate",
261                 .cb = askconsole,
262                 .multi = 1,
263         }, {
264                 .name = "respawnlate",
265                 .cb = rcrespawn,
266                 .multi = 1,
267         }
268 };
269 
270 static int add_action(struct init_action *a, const char *name)
271 {
272         int i;
273 
274         for (i = 0; i < ARRAY_SIZE(handlers); i++)
275                 if (!strcmp(handlers[i].name, name)) {
276                         a->handler = &handlers[i];
277                         list_add_tail(&a->list, &actions);
278                         return 0;
279                 }
280         ERROR("Unknown init handler %s\n", name);
281         return -1;
282 }
283 
284 void procd_inittab_run(const char *handler)
285 {
286         struct init_action *a;
287 
288         list_for_each_entry(a, &actions, list)
289                 if (!strcmp(a->handler->name, handler)) {
290                         a->handler->cb(a);
291                         if (!a->handler->multi)
292                                 break;
293                 }
294 }
295 
296 void procd_inittab(void)
297 {
298 #define LINE_LEN        128
299         FILE *fp = fopen(tab, "r");
300         struct init_action *a;
301         regex_t pat_inittab;
302         regmatch_t matches[5];
303         char *line;
304 
305         if (!fp) {
306                 ERROR("Failed to open %s: %m\n", tab);
307                 return;
308         }
309 
310         regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):(.*)", REG_EXTENDED);
311         line = malloc(LINE_LEN);
312         a = calloc(1, sizeof(struct init_action));
313 
314         while (fgets(line, LINE_LEN, fp)) {
315                 char *tags[TAG_PROCESS + 1];
316                 char *tok;
317                 int i;
318                 int len = strlen(line);
319 
320                 while (isspace(line[len - 1]))
321                         len--;
322                 line[len] = 0;
323 
324                 if (*line == '#')
325                         continue;
326 
327                 if (regexec(&pat_inittab, line, 5, matches, 0))
328                         continue;
329 
330                 DEBUG(4, "Parsing inittab - %s\n", line);
331 
332                 for (i = TAG_ID; i <= TAG_PROCESS; i++) {
333                         line[matches[i].rm_eo] = '\0';
334                         tags[i] = &line[matches[i + 1].rm_so];
335                 };
336 
337                 tok = strtok(tags[TAG_PROCESS], " ");
338                 for (i = 0; i < (MAX_ARGS - 1) && tok; i++) {
339                         a->argv[i] = tok;
340                         tok = strtok(NULL, " ");
341                 }
342                 a->argv[i] = NULL;
343                 a->id = tags[TAG_ID];
344                 a->line = line;
345 
346                 if (add_action(a, tags[TAG_ACTION]))
347                         continue;
348                 line = malloc(LINE_LEN);
349                 a = calloc(1, sizeof(struct init_action));
350         }
351 
352         fclose(fp);
353         free(line);
354         free(a);
355         regfree(&pat_inittab);
356 }
357 

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