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 }