/*
    * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
    * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
    *
    * This program is free software; you can redistribute it and/or modify
    * it under the terms of the GNU Lesser General Public License version 2.1
    * as published by the Free Software Foundation
    *
    * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <fcntl.h>
  #include <pwd.h>
  #include <sys/reboot.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <sys/types.h>
  #include <signal.h>
  
  #include "container.h"
  #include "procd.h"
  #include "syslog.h"
  #include "plug/hotplug.h"
  #include "watchdog.h"
  #include "service/service.h"
  #include "utils/utils.h"
  
  enum {
          STATE_NONE = 0,
          STATE_EARLY,
          STATE_UBUS,
          STATE_INIT,
          STATE_RUNNING,
          STATE_SHUTDOWN,
          STATE_HALT,
          __STATE_MAX,
  };
  
  static int state = STATE_NONE;
  static int reboot_event;
  
  static void set_stdio(const char* tty)
  {
          if (chdir("/dev") ||
              !freopen(tty, "r", stdin) ||
              !freopen(tty, "w", stdout) ||
              !freopen(tty, "w", stderr) ||
              chdir("/"))
                  ERROR("failed to set stdio: %m\n");
          else
                  fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
  }
  
  static void set_console(void)
  {
          const char* tty;
          char* split;
          char line[ 20 ];
          const char* try[] = { "tty0", "console", NULL }; /* Try the most common outputs */
          int f, i = 0;
  
          tty = get_cmdline_val("console",line,sizeof(line));
          if (tty != NULL) {
                  split = strchr(tty, ',');
                  if ( split != NULL )
                          *split = '\0';
          } else {
                  // Try a default
                  tty=try[i];
                  i++;
          }
  
          if (chdir("/dev")) {
                  ERROR("failed to change dir to /dev: %m\n");
                  return;
          }
          while (tty!=NULL) {
                  f = open(tty, O_RDONLY);
                  if (f >= 0) {
                          close(f);
                          break;
                  }
  
                  tty=try[i];
                  i++;
          }
          if (chdir("/"))
                  ERROR("failed to change dir to /: %m\n");
  
          if (tty != NULL)
                  set_stdio(tty);
  }
  
  static void perform_halt()
  {
         if (reboot_event == RB_POWER_OFF)
                 LOG("- power down -\n");
         else
                 LOG("- reboot -\n");
 
         /* Allow time for last message to reach serial console, etc */
         sleep(1);
 
         if (is_container()) {
                 reboot(reboot_event);
                 exit(EXIT_SUCCESS);
                 return;
         }
 
         /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
          * in linux/kernel/sys.c, which can cause the machine to panic when
          * the init process exits... */
         if (!vfork()) { /* child */
                 reboot(reboot_event);
                 _exit(EXIT_SUCCESS);
         }
 
         while (1)
                 sleep(1);
 }
 
 static void state_enter(void)
 {
         char ubus_cmd[] = "/sbin/ubusd";
         struct passwd *p;
 
         switch (state) {
         case STATE_EARLY:
                 LOG("- early -\n");
                 watchdog_init(0);
                 hotplug("/etc/hotplug.json");
                 procd_coldplug();
                 break;
 
         case STATE_UBUS:
                 // try to reopen incase the wdt was not available before coldplug
                 watchdog_init(0);
                 set_stdio("console");
                 p = getpwnam("ubus");
                 if (p) {
                         int ret;
                         LOG("- ubus -\n");
                         mkdir(p->pw_dir, 0755);
                         ret = chown(p->pw_dir, p->pw_uid, p->pw_gid);
                         if (ret)
                                 LOG("- ubus - failed to chown(%s)\n", p->pw_dir);
                 } else {
                         LOG("- ubus (running as root!) -\n");
                 }
 
                 procd_connect_ubus();
                 service_start_early("ubus", ubus_cmd, p?"ubus":NULL, p?"ubus":NULL);
                 break;
 
         case STATE_INIT:
                 LOG("- init -\n");
                 procd_inittab();
                 procd_inittab_run("respawn");
                 procd_inittab_run("askconsole");
                 procd_inittab_run("askfirst");
                 procd_inittab_run("sysinit");
 
                 // switch to syslog log channel
                 ulog_open(ULOG_SYSLOG, LOG_DAEMON, "procd");
                 break;
 
         case STATE_RUNNING:
                 LOG("- init complete -\n");
                 procd_inittab_run("respawnlate");
                 procd_inittab_run("askconsolelate");
                 break;
 
         case STATE_SHUTDOWN:
                 /* Redirect output to the console for the users' benefit */
                 set_console();
                 LOG("- shutdown -\n");
                 procd_inittab_run("shutdown");
                 sync();
                 break;
 
         case STATE_HALT:
                 // To prevent killed processes from interrupting the sleep
                 signal(SIGCHLD, SIG_IGN);
                 LOG("- SIGTERM processes -\n");
                 kill(-1, SIGTERM);
                 sync();
                 sleep(1);
                 LOG("- SIGKILL processes -\n");
                 kill(-1, SIGKILL);
                 sync();
                 sleep(1);
 #ifndef DISABLE_INIT
                 perform_halt();
 #else
                 exit(EXIT_SUCCESS);
 #endif
                 break;
 
         default:
                 ERROR("Unhandled state %d\n", state);
                 return;
         };
 }
 
 void procd_state_next(void)
 {
         DEBUG(4, "Change state %d -> %d\n", state, state + 1);
         state++;
         state_enter();
 }
 
 void procd_state_ubus_connect(void)
 {
         if (state == STATE_UBUS)
                 procd_state_next();
 }
 
 void procd_shutdown(int event)
 {
         if (state >= STATE_SHUTDOWN)
                 return;
         DEBUG(2, "Shutting down system with event %x\n", event);
         reboot_event = event;
         state = STATE_SHUTDOWN;
         state_enter();
 }
 

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