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 #include "rcS.h"
  29
  30 #define TAG_ID          0
  31 #define TAG_RUNLVL      1
  32 #define TAG_ACTION      2
  33 #define TAG_PROCESS     3
  34
  35 #define MAX_ARGS        8
  36
  37 struct init_action;
  38 const char *console;
  39
  40 struct init_handler {
  41         const char *name;
  42         void (*cb) (struct init_action *a);
  43         int multi;
  44 };
  45
  46 struct init_action {
  47         struct list_head list;
  48
  49         char *id;
  50         char *argv[MAX_ARGS];
  51         char *line;
  52
  53         struct init_handler *handler;
  54         struct uloop_process proc;
  55
  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 LIST_HEAD(actions);
  64
  65 static void fork_worker(struct init_action *a)
  66 {
  67         a->proc.pid = fork();
  68         if (!a->proc.pid) {
  69                 execvp(a->argv[0], a->argv);
  70                 ERROR("Failed to execute %s\n", a->argv[0]);
  71                 exit(-1);
  72         }
  73
  74         if (a->proc.pid > 0) {
  75                 DEBUG(2, "Launched new %s action, pid=%d\n",
  76                                         a->handler->name,
  77                                         (int) a->proc.pid);
  78                 uloop_process_add(&a->proc);
  79         }
  80 }
  81
  82 static void child_exit(struct uloop_process *proc, int ret)
  83 {
  84         struct init_action *a = container_of(proc, struct init_action, proc);
  85
  86         DEBUG(2, "pid:%d\n", proc->pid);
  87         uloop_timeout_set(&a->tout, a->respawn);
  88 }
  89
  90 static void respawn(struct uloop_timeout *tout)
  91 {
  92         struct init_action *a = container_of(tout, struct init_action, tout);
  93         fork_worker(a);
  94 }
  95
  96 static void rcdone(struct runqueue *q)
  97 {
  98         procd_state_next();
  99 }
 100
 101 static void runrc(struct init_action *a)
 102 {
 103         if (!a->argv[1] || !a->argv[2]) {
 104                 ERROR("valid format is rcS <S|K> <param>\n");
 105                 return;
 106         }
 107         rcS(a->argv[1], a->argv[2], rcdone);
 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_worker(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_worker(a);
 173
 174 err_out:
 175         regfree(&pat_cmdline);
 176 }
 177
 178 static void rcrespawn(struct init_action *a)
 179 {
 180         a->tout.cb = respawn;
 181         a->respawn = 500;
 182
 183         a->proc.cb = child_exit;
 184         fork_worker(a);
 185 }
 186
 187 static struct init_handler handlers[] = {
 188         {
 189                 .name = "sysinit",
 190                 .cb = runrc,
 191         }, {
 192                 .name = "shutdown",
 193                 .cb = runrc,
 194         }, {
 195                 .name = "askfirst",
 196                 .cb = askfirst,
 197                 .multi = 1,
 198         }, {
 199                 .name = "askconsole",
 200                 .cb = askconsole,
 201                 .multi = 1,
 202         }, {
 203                 .name = "respawn",
 204                 .cb = rcrespawn,
 205                 .multi = 1,
 206         }
 207 };
 208
 209 static int add_action(struct init_action *a, const char *name)
 210 {
 211         int i;
 212
 213         for (i = 0; i < ARRAY_SIZE(handlers); i++)
 214                 if (!strcmp(handlers[i].name, name)) {
 215                         a->handler = &handlers[i];
 216                         list_add_tail(&a->list, &actions);
 217                         return 0;
 218                 }
 219         ERROR("Unknown init handler %s\n", name);
 220         return -1;
 221 }
 222
 223 void procd_inittab_run(const char *handler)
 224 {
 225         struct init_action *a;
 226
 227         list_for_each_entry(a, &actions, list)
 228                 if (!strcmp(a->handler->name, handler)) {
 229                         if (a->handler->multi) {
 230                                 a->handler->cb(a);
 231                                 continue;
 232                         }
 233                         a->handler->cb(a);
 234                         break;
 235                 }
 236 }
 237
 238 void procd_inittab(void)
 239 {
 240 #define LINE_LEN        128
 241         FILE *fp = fopen(tab, "r");
 242         struct init_action *a;
 243         regex_t pat_inittab;
 244         regmatch_t matches[5];
 245         char *line;
 246
 247         if (!fp) {
 248                 ERROR("Failed to open %s\n", tab);
 249                 return;
 250         }
 251
 252         regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9/[.-.]. ]*)", REG_EXTENDED);
 253         line = malloc(LINE_LEN);
 254         a = malloc(sizeof(struct init_action));
 255         memset(a, 0, sizeof(struct init_action));
 256
 257         while (fgets(line, LINE_LEN, fp)) {
 258                 char *tags[TAG_PROCESS + 1];
 259                 char *tok;
 260                 int i;
 261
 262                 if (*line == '#')
 263                         continue;
 264
 265                 if (regexec(&pat_inittab, line, 5, matches, 0))
 266                         continue;
 267
 268                 DEBUG(2, "Parsing inittab - %s", line);
 269
 270                 for (i = TAG_ID; i <= TAG_PROCESS; i++) {
 271                         line[matches[i].rm_eo] = '\0';
 272                         tags[i] = &line[matches[i + 1].rm_so];
 273                 };
 274
 275                 tok = strtok(tags[TAG_PROCESS], " ");
 276                 for (i = 0; i < (MAX_ARGS - i - 1) && tok; i++) {
 277                         a->argv[i] = tok;
 278                         tok = strtok(NULL, " ");
 279                 }
 280                 a->argv[i] = NULL;
 281                 a->id = tags[TAG_ID];
 282                 a->line = line;
 283
 284                 if (add_action(a, tags[TAG_ACTION]))
 285                         continue;
 286                 line = malloc(LINE_LEN);
 287                 a = malloc(sizeof(struct init_action));
 288                 memset(a, 0, sizeof(struct init_action));
 289         }
 290
 291         fclose(fp);
 292         free(line);
 293         free(a);
 294         regfree(&pat_inittab);
 295 }