init/halt.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Poweroff reboot and halt, oh my.
   4  *
   5  * Copyright 2006 by Rob Landley <rob@landley.net>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9 //config:config HALT
  10 //config:       bool "halt (4 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       Stop all processes and halt the system.
  14 //config:
  15 //config:config POWEROFF
  16 //config:       bool "poweroff (4 kb)"
  17 //config:       default y
  18 //config:       help
  19 //config:       Stop all processes and power off the system.
  20 //config:
  21 //config:config REBOOT
  22 //config:       bool "reboot (4 kb)"
  23 //config:       default y
  24 //config:       help
  25 //config:       Stop all processes and reboot the system.
  26 //config:
  27 //config:config FEATURE_WAIT_FOR_INIT
  28 //config:       bool "Before signaling init, make sure it is ready for it"
  29 //config:       default y
  30 //config:       depends on HALT || POWEROFF || REBOOT
  31 //config:       help
  32 //config:       In rare cases, poweroff may be commanded by firmware to OS
  33 //config:       even before init process exists. On Linux, this spawns
  34 //config:       "/sbin/poweroff" very early. This option adds code
  35 //config:       which checks that init is ready to receive poweroff
  36 //config:       commands. Code size increase of ~80 bytes.
  37 //config:
  38 //config:config FEATURE_CALL_TELINIT
  39 //config:       bool "Call telinit on shutdown and reboot"
  40 //config:       default y
  41 //config:       depends on (HALT || POWEROFF || REBOOT) && !INIT
  42 //config:       help
  43 //config:       Call an external program (normally telinit) to facilitate
  44 //config:       a switch to a proper runlevel.
  45 //config:
  46 //config:       This option is only available if you selected halt and friends,
  47 //config:       but did not select init.
  48 //config:
  49 //config:config TELINIT_PATH
  50 //config:       string "Path to telinit executable"
  51 //config:       default "/sbin/telinit"
  52 //config:       depends on FEATURE_CALL_TELINIT
  53 //config:       help
  54 //config:       When busybox halt and friends have to call external telinit
  55 //config:       to facilitate proper shutdown, this path is to be used when
  56 //config:       locating telinit executable.
  57
  58 //applet:IF_HALT(APPLET(halt, BB_DIR_SBIN, BB_SUID_DROP))
  59 //                   APPLET_ODDNAME:name      main  location     suid_type     help
  60 //applet:IF_POWEROFF(APPLET_ODDNAME(poweroff, halt, BB_DIR_SBIN, BB_SUID_DROP, poweroff))
  61 //applet:IF_REBOOT(  APPLET_ODDNAME(reboot,   halt, BB_DIR_SBIN, BB_SUID_DROP, reboot))
  62
  63 //kbuild:lib-$(CONFIG_HALT) += halt.o
  64 //kbuild:lib-$(CONFIG_POWEROFF) += halt.o
  65 //kbuild:lib-$(CONFIG_REBOOT) += halt.o
  66
  67 //usage:#define halt_trivial_usage
  68 //usage:       "[-d DELAY] [-n] [-f]" IF_FEATURE_WTMP(" [-w]")
  69 //usage:#define halt_full_usage "\n\n"
  70 //usage:       "Halt the system\n"
  71 //usage:     "\n        -d SEC  Delay interval"
  72 //usage:     "\n        -n      Do not sync"
  73 //usage:     "\n        -f      Force (don't go through init)"
  74 //usage:        IF_FEATURE_WTMP(
  75 //usage:     "\n        -w      Only write a wtmp record"
  76 //usage:        )
  77 //usage:
  78 //usage:#define poweroff_trivial_usage
  79 //usage:       "[-d DELAY] [-n] [-f]"
  80 //usage:#define poweroff_full_usage "\n\n"
  81 //usage:       "Halt and shut off power\n"
  82 //usage:     "\n        -d SEC  Delay interval"
  83 //usage:     "\n        -n      Do not sync"
  84 //usage:     "\n        -f      Force (don't go through init)"
  85 //usage:
  86 //usage:#define reboot_trivial_usage
  87 //usage:       "[-d DELAY] [-n] [-f]"
  88 //usage:#define reboot_full_usage "\n\n"
  89 //usage:       "Reboot the system\n"
  90 //usage:     "\n        -d SEC  Delay interval"
  91 //usage:     "\n        -n      Do not sync"
  92 //usage:     "\n        -f      Force (don't go through init)"
  93
  94 #include "libbb.h"
  95 #include "reboot.h"
  96
  97 #if ENABLE_FEATURE_WTMP
  98 #include <sys/utsname.h>
  99
 100 static void write_wtmp(void)
 101 {
 102         struct utmpx utmp;
 103         struct utsname uts;
 104         /* "man utmp" says wtmp file should *not* be created automagically */
 105         /*if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
 106                 close(creat(bb_path_wtmp_file, 0664));
 107         }*/
 108         memset(&utmp, 0, sizeof(utmp));
 109         utmp.ut_tv.tv_sec = time(NULL);
 110         strcpy(utmp.ut_user, "shutdown"); /* it is wide enough */
 111         utmp.ut_type = RUN_LVL;
 112         utmp.ut_id[0] = '~'; utmp.ut_id[1] = '~'; /* = strcpy(utmp.ut_id, "~~"); */
 113         utmp.ut_line[0] = '~'; utmp.ut_line[1] = '~'; /* = strcpy(utmp.ut_line, "~~"); */
 114         uname(&uts);
 115         safe_strncpy(utmp.ut_host, uts.release, sizeof(utmp.ut_host));
 116         updwtmpx(bb_path_wtmp_file, &utmp);
 117 }
 118 #else
 119 #define write_wtmp() ((void)0)
 120 #endif
 121
 122 #if ENABLE_FEATURE_WAIT_FOR_INIT
 123 /* In Linux, "poweroff" may be spawned even before init.
 124  * For example, with ACPI:
 125  * linux/drivers/acpi/bus.c:
 126  *  static void sb_notify_work(struct work_struct *dummy)
 127  *      orderly_poweroff(true);
 128  * linux/kernel/reboot.c:
 129  *  static int run_cmd(const char *cmd)
 130  *      ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
 131  *  poweroff_cmd[] = "/sbin/poweroff";
 132  *  static int __orderly_poweroff(bool force)
 133  *      ret = run_cmd(poweroff_cmd);
 134  *
 135  * We want to make sure init exists and listens to signals.
 136  */
 137 static int init_was_not_there(void)
 138 {
 139         enum { initial = 5 }; /* 5 seconds should be plenty for timeout */
 140         int cnt = initial - 1;
 141
 142         /* Just existence of PID 1 does not mean it installed
 143          * the handlers already.
 144          */
 145 #if 0
 146         while (kill(1, 0) != 0 && --cnt >= 0)
 147                 sleep(1);
 148 #endif
 149         /* ... so let's wait for some evidence a usual startup event,
 150          * mounting of /proc, happened. By that time init should be ready
 151          * for signals.
 152          */
 153         while (access("/proc/meminfo", F_OK) != 0 && --cnt >= 0)
 154                 sleep(1);
 155
 156         /* Does it look like init wasn't there? */
 157         return (cnt != initial - 1);
 158 }
 159 #else
 160   /* Assume it's always there */
 161 # define init_was_not_there() 0
 162 #endif
 163
 164 int halt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 165 int halt_main(int argc UNUSED_PARAM, char **argv)
 166 {
 167         static const int magic[] = {
 168                 RB_HALT_SYSTEM,
 169                 RB_POWER_OFF,
 170                 RB_AUTOBOOT
 171         };
 172         static const smallint signals[] = { SIGUSR1, SIGUSR2, SIGTERM };
 173
 174         int delay = 0;
 175         int which, flags, rc;
 176
 177         /* Figure out which applet we're running */
 178         if (ENABLE_HALT && !ENABLE_POWEROFF && !ENABLE_REBOOT)
 179                 which = 0;
 180         else
 181         if (!ENABLE_HALT && ENABLE_POWEROFF && !ENABLE_REBOOT)
 182                 which = 1;
 183         else
 184         if (!ENABLE_HALT && !ENABLE_POWEROFF && ENABLE_REBOOT)
 185                 which = 2;
 186         else
 187         for (which = 0; "hpr"[which] != applet_name[0]; which++)
 188                 continue;
 189
 190         /* Parse and handle arguments */
 191         /* We support -w even if !ENABLE_FEATURE_WTMP,
 192          * in order to not break scripts.
 193          * -i (shut down network interfaces) is ignored.
 194          */
 195         flags = getopt32(argv, "d:+nfwi", &delay);
 196
 197         sleep(delay);
 198
 199         write_wtmp();
 200
 201         if (flags & 8) /* -w */
 202                 return EXIT_SUCCESS;
 203
 204         if (!(flags & 2)) /* no -n */
 205                 sync();
 206
 207         /* Perform action. */
 208         rc = 1;
 209         if (!(flags & 4)) { /* no -f */
 210 //TODO: I tend to think that signalling linuxrc is wrong
 211 // pity original author didn't comment on it...
 212                 if (ENABLE_LINUXRC) {
 213                         /* talk to linuxrc */
 214                         /* bbox init/linuxrc assumed */
 215                         pid_t *pidlist = find_pid_by_name("linuxrc");
 216                         if (pidlist[0] > 0)
 217                                 rc = kill(pidlist[0], signals[which]);
 218                         if (ENABLE_FEATURE_CLEAN_UP)
 219                                 free(pidlist);
 220                 }
 221                 if (rc) {
 222                         /* talk to init */
 223                         if (!ENABLE_FEATURE_CALL_TELINIT) {
 224                                 /* bbox init assumed */
 225                                 rc = kill(1, signals[which]);
 226                                 if (init_was_not_there())
 227                                         rc = kill(1, signals[which]);
 228                         } else {
 229                                 /* SysV style init assumed */
 230                                 /* runlevels:
 231                                  * 0 == shutdown
 232                                  * 6 == reboot */
 233                                 execlp(CONFIG_TELINIT_PATH,
 234                                                 CONFIG_TELINIT_PATH,
 235                                                 which == 2 ? "6" : "0",
 236                                                 (char *)NULL
 237                                 );
 238                                 bb_perror_msg_and_die("can't execute '%s'",
 239                                                 CONFIG_TELINIT_PATH);
 240                         }
 241                 }
 242         } else {
 243                 rc = reboot(magic[which]);
 244         }
 245
 246         if (rc)
 247                 bb_perror_nomsg_and_die();
 248         return rc;
 249 }