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 }