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 #include <sys/types.h>
  16 #include <sys/stat.h>
  17
  18 #include <fcntl.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <regex.h>
  23
  24 #include <libubox/utils.h>
  25 #include <libubox/list.h>
  26
  27 #include "procd.h"
  28
  29 #define TAG_ID          0
  30 #define TAG_RUNLVL      1
  31 #define TAG_ACTION      2
  32 #define TAG_PROCESS     3
  33
  34 #define MAX_ARGS        8
  35
  36 struct init_action;
  37 const char *console;
  38
  39 struct init_handler {
  40         const char *name;
  41         void (*cb) (struct init_action *a);
  42         int atomic;
  43 };
  44
  45 struct init_action {
  46         struct list_head list;
  47
  48         char *id;
  49         char *argv[MAX_ARGS];
  50         char *line;
  51
  52         struct init_handler *handler;
  53         struct uloop_process proc;
  54
  55         int pending;
  56         int respawn;
  57         struct uloop_timeout tout;
  58 };
  59
  60 static const char *tab = "/etc/inittab";
  61 static char *ask = "/sbin/askfirst";
  62
  63 static struct init_action *pending;
  64
  65 static LIST_HEAD(actions);
  66
  67 static void fork_script(struct init_action *a)
  68 {
  69         a->proc.pid = fork();
  70         if (!a->proc.pid) {
  71                 execvp(a->argv[0], a->argv);
  72                 ERROR("Failed to execute %s\n", a->argv[0]);
  73                 exit(-1);
  74         }
  75
  76         if (a->proc.pid > 0) {
  77                 DEBUG(2, "Launched new %s action, pid=%d\n",
  78                                         a->handler->name,
  79                                         (int) a->proc.pid);
  80                 uloop_process_add(&a->proc);
  81         }
  82 }
  83
  84 static void child_exit(struct uloop_process *proc, int ret)
  85 {
  86         struct init_action *a = container_of(proc, struct init_action, proc);
  87
  88         DEBUG(2, "pid:%d\n", proc->pid);
  89         if (a->tout.cb) {
  90                 uloop_timeout_set(&a->tout, a->respawn);
  91         } else {
  92                 a->pending = 0;
  93                 pending = NULL;
  94                 procd_state_next();
  95         }
  96 }
  97
  98 static void respawn(struct uloop_timeout *tout)
  99 {
 100         struct init_action *a = container_of(tout, struct init_action, tout);
 101         fork_script(a);
 102 }
 103
 104 static void runscript(struct init_action *a)
 105 {
 106         a->proc.cb = child_exit;
 107         fork_script(a);
 108 }
 109
 110 static void askfirst(struct init_action *a)
 111 {
 112         struct stat s;
 113         int i;
 114
 115         chdir("/dev");
 116         i = stat(a->id, &s);
 117         chdir("/");
 118         if (i || (console && !strcmp(console, a->id))) {
 119                 DEBUG(2, "Skipping %s\n", a->id);
 120                 return;
 121         }
 122
 123         a->tout.cb = respawn;
 124         for (i = MAX_ARGS - 2; i >= 2; i--)
 125                 a->argv[i] = a->argv[i - 2];
 126         a->argv[0] = ask;
 127         a->argv[1] = a->id;
 128         a->respawn = 500;
 129
 130         a->proc.cb = child_exit;
 131         fork_script(a);
 132 }
 133
 134 static void askconsole(struct init_action *a)
 135 {
 136         struct stat s;
 137         char line[256], *tty;
 138         int i, r, fd = open("/proc/cmdline", O_RDONLY);
 139         regex_t pat_cmdline;
 140         regmatch_t matches[2];
 141
 142         if (!fd)
 143                 return;
 144
 145         r = read(fd, line, sizeof(line) - 1);
 146         line[r] = '\0';
 147         close(fd);
 148
 149         regcomp(&pat_cmdline, "console=([a-zA-Z0-9]*)", REG_EXTENDED);
 150         if (regexec(&pat_cmdline, line, 2, matches, 0))
 151                 goto err_out;
 152         line[matches[1].rm_eo] = '\0';
 153         tty = &line[matches[1].rm_so];
 154
 155         chdir("/dev");
 156         i = stat(tty, &s);
 157         chdir("/");
 158         if (i) {
 159                 DEBUG(2, "skipping %s\n", tty);
 160                 goto err_out;
 161         }
 162         console = strdup(tty);
 163
 164         a->tout.cb = respawn;
 165         for (i = MAX_ARGS - 2; i >= 2; i--)
 166                 a->argv[i] = a->argv[i - 2];
 167         a->argv[0] = ask;
 168         a->argv[1] = strdup(tty);
 169         a->respawn = 500;
 170
 171         a->proc.cb = child_exit;
 172         fork_script(a);
 173 err_out:
 174         regfree(&pat_cmdline);
 175 }
 176
 177 static struct init_handler handlers[] = {
 178         {
 179                 .name = "sysinit",
 180                 .cb = runscript,
 181         }, {
 182                 .name = "shutdown",
 183                 .cb = runscript,
 184         }, {
 185                 .name = "askfirst",
 186                 .cb = askfirst,
 187                 .atomic = 1,
 188         }, {
 189                 .name = "askconsole",
 190                 .cb = askconsole,
 191                 .atomic = 1,
 192         }
 193 };
 194
 195 static int add_action(struct init_action *a, const char *name)
 196 {
 197         int i;
 198
 199         for (i = 0; i < ARRAY_SIZE(handlers); i++)
 200                 if (!strcmp(handlers[i].name, name)) {
 201                         a->handler = &handlers[i];
 202                         list_add_tail(&a->list, &actions);
 203                         return 0;
 204                 }
 205         ERROR("Unknown init handler %s\n", name);
 206         return -1;
 207 }
 208
 209 void procd_inittab_run(const char *handler)
 210 {
 211         struct init_action *a;
 212
 213         list_for_each_entry(a, &actions, list)
 214                 if (!strcmp(a->handler->name, handler)) {
 215                         if (a->handler->atomic) {
 216                                 a->handler->cb(a);
 217                                 continue;
 218                         }
 219                         if (pending || a->pending)
 220                                 break;
 221                         a->pending = 1;
 222                         pending = a;
 223                         a->handler->cb(a);
 224                 }
 225 }
 226
 227 void procd_inittab(void)
 228 {
 229 #define LINE_LEN        128
 230         FILE *fp = fopen(tab, "r");
 231         struct init_action *a;
 232         regex_t pat_inittab;
 233         regmatch_t matches[5];
 234         char *line;
 235
 236         if (!fp) {
 237                 ERROR("Failed to open %s\n", tab);
 238                 return;
 239         }
 240
 241         regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9/[.-.]. ]*)", REG_EXTENDED);
 242         line = malloc(LINE_LEN);
 243         a = malloc(sizeof(struct init_action));
 244         memset(a, 0, sizeof(struct init_action));
 245
 246         while (fgets(line, LINE_LEN, fp)) {
 247                 char *tags[TAG_PROCESS + 1];
 248                 char *tok;
 249                 int i;
 250
 251                 if (*line == '#')
 252                         continue;
 253
 254                 if (regexec(&pat_inittab, line, 5, matches, 0))
 255                         continue;
 256
 257                 DEBUG(2, "Parsing inittab - %s", line);
 258
 259                 for (i = TAG_ID; i <= TAG_PROCESS; i++) {
 260                         line[matches[i].rm_eo] = '\0';
 261                         tags[i] = &line[matches[i + 1].rm_so];
 262                 };
 263
 264                 tok = strtok(tags[TAG_PROCESS], " ");
 265                 for (i = 0; i < (MAX_ARGS - i - 1) && tok; i++) {
 266                         a->argv[i] = tok;
 267                         tok = strtok(NULL, " ");
 268                 }
 269                 a->argv[i] = NULL;
 270                 a->id = tags[TAG_ID];
 271                 a->line = line;
 272
 273                 if (add_action(a, tags[TAG_ACTION]))
 274                         continue;
 275                 line = malloc(LINE_LEN);
 276                 a = malloc(sizeof(struct init_action));
 277                 memset(a, 0, sizeof(struct init_action));
 278         }
 279
 280         fclose(fp);
 281         free(line);
 282         free(a);
 283         regfree(&pat_inittab);
 284 }