[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini init implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
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| 6 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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| 7 | * Adjusted by so many folks, it's impossible to keep track.
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| 8 | *
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[2725] | 9 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 10 | */
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| 11 |
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[3232] | 12 | //applet:IF_INIT(APPLET(init, BB_DIR_SBIN, BB_SUID_DROP))
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| 13 | //applet:IF_FEATURE_INITRD(APPLET_ODDNAME(linuxrc, init, BB_DIR_ROOT, BB_SUID_DROP, linuxrc))
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[2725] | 14 |
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| 15 | //kbuild:lib-$(CONFIG_INIT) += init.o
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| 16 |
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| 17 | //config:config INIT
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| 18 | //config: bool "init"
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| 19 | //config: default y
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| 20 | //config: select FEATURE_SYSLOG
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| 21 | //config: help
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| 22 | //config: init is the first program run when the system boots.
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| 23 | //config:
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| 24 | //config:config FEATURE_USE_INITTAB
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| 25 | //config: bool "Support reading an inittab file"
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| 26 | //config: default y
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| 27 | //config: depends on INIT
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| 28 | //config: help
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| 29 | //config: Allow init to read an inittab file when the system boot.
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| 30 | //config:
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| 31 | //config:config FEATURE_KILL_REMOVED
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| 32 | //config: bool "Support killing processes that have been removed from inittab"
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| 33 | //config: default n
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| 34 | //config: depends on FEATURE_USE_INITTAB
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| 35 | //config: help
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| 36 | //config: When respawn entries are removed from inittab and a SIGHUP is
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| 37 | //config: sent to init, this option will make init kill the processes
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| 38 | //config: that have been removed.
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| 39 | //config:
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| 40 | //config:config FEATURE_KILL_DELAY
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| 41 | //config: int "How long to wait between TERM and KILL (0 - send TERM only)" if FEATURE_KILL_REMOVED
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| 42 | //config: range 0 1024
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| 43 | //config: default 0
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| 44 | //config: depends on FEATURE_KILL_REMOVED
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| 45 | //config: help
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| 46 | //config: With nonzero setting, init sends TERM, forks, child waits N
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| 47 | //config: seconds, sends KILL and exits. Setting it too high is unwise
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| 48 | //config: (child will hang around for too long and could actually kill
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| 49 | //config: the wrong process!)
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| 50 | //config:
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| 51 | //config:config FEATURE_INIT_SCTTY
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| 52 | //config: bool "Run commands with leading dash with controlling tty"
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| 53 | //config: default y
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| 54 | //config: depends on INIT
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| 55 | //config: help
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| 56 | //config: If this option is enabled, init will try to give a controlling
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| 57 | //config: tty to any command which has leading hyphen (often it's "-/bin/sh").
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| 58 | //config: More precisely, init will do "ioctl(STDIN_FILENO, TIOCSCTTY, 0)".
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| 59 | //config: If device attached to STDIN_FILENO can be a ctty but is not yet
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| 60 | //config: a ctty for other session, it will become this process' ctty.
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| 61 | //config: This is not the traditional init behavour, but is often what you want
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| 62 | //config: in an embedded system where the console is only accessed during
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| 63 | //config: development or for maintenance.
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| 64 | //config: NB: using cttyhack applet may work better.
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| 65 | //config:
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| 66 | //config:config FEATURE_INIT_SYSLOG
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| 67 | //config: bool "Enable init to write to syslog"
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| 68 | //config: default y
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| 69 | //config: depends on INIT
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| 70 | //config:
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| 71 | //config:config FEATURE_EXTRA_QUIET
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| 72 | //config: bool "Be _extra_ quiet on boot"
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| 73 | //config: default y
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| 74 | //config: depends on INIT
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| 75 | //config: help
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| 76 | //config: Prevent init from logging some messages to the console during boot.
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| 77 | //config:
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| 78 | //config:config FEATURE_INIT_COREDUMPS
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| 79 | //config: bool "Support dumping core for child processes (debugging only)"
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| 80 | //config: default y
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| 81 | //config: depends on INIT
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| 82 | //config: help
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| 83 | //config: If this option is enabled and the file /.init_enable_core
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| 84 | //config: exists, then init will call setrlimit() to allow unlimited
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| 85 | //config: core file sizes. If this option is disabled, processes
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| 86 | //config: will not generate any core files.
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| 87 | //config:
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| 88 | //config:config FEATURE_INITRD
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| 89 | //config: bool "Support running init from within an initrd (not initramfs)"
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| 90 | //config: default y
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| 91 | //config: depends on INIT
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| 92 | //config: help
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| 93 | //config: Legacy support for running init under the old-style initrd. Allows
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| 94 | //config: the name linuxrc to act as init, and it doesn't assume init is PID 1.
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| 95 | //config:
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| 96 | //config: This does not apply to initramfs, which runs /init as PID 1 and
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| 97 | //config: requires no special support.
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| 98 | //config:
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| 99 | //config:config INIT_TERMINAL_TYPE
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| 100 | //config: string "Initial terminal type"
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| 101 | //config: default "linux"
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| 102 | //config: depends on INIT
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| 103 | //config: help
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| 104 | //config: This is the initial value set by init for the TERM environment
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| 105 | //config: variable. This variable is used by programs which make use of
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| 106 | //config: extended terminal capabilities.
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| 107 | //config:
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| 108 | //config: Note that on Linux, init attempts to detect serial terminal and
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| 109 | //config: sets TERM to "vt102" if one is found.
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| 110 |
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[3232] | 111 | #define DEBUG_SEGV_HANDLER 0
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| 112 |
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[1765] | 113 | #include "libbb.h"
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[2725] | 114 | #include <syslog.h>
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[821] | 115 | #include <paths.h>
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[2725] | 116 | #include <sys/resource.h>
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| 117 | #ifdef __linux__
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[3232] | 118 | # include <linux/vt.h>
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| 119 | # include <sys/sysinfo.h>
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[2725] | 120 | #endif
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| 121 | #include "reboot.h" /* reboot() constants */
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[821] | 122 |
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[3232] | 123 | #if DEBUG_SEGV_HANDLER
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| 124 | # undef _GNU_SOURCE
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| 125 | # define _GNU_SOURCE 1
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| 126 | # undef __USE_GNU
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| 127 | # define __USE_GNU 1
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| 128 | # include <execinfo.h>
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| 129 | # include <sys/ucontext.h>
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| 130 | #endif
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| 131 |
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[2725] | 132 | /* Used only for sanitizing purposes in set_sane_term() below. On systems where
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| 133 | * the baud rate is stored in a separate field, we can safely disable them. */
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| 134 | #ifndef CBAUD
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| 135 | # define CBAUD 0
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| 136 | # define CBAUDEX 0
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[821] | 137 | #endif
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| 138 |
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[2725] | 139 | /* Was a CONFIG_xxx option. A lot of people were building
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| 140 | * not fully functional init by switching it on! */
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| 141 | #define DEBUG_INIT 0
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| 142 |
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| 143 | #define COMMAND_SIZE 256
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[1765] | 144 | #define CONSOLE_NAME_SIZE 32
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[821] | 145 |
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[2725] | 146 | /* Default sysinit script. */
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[821] | 147 | #ifndef INIT_SCRIPT
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[2725] | 148 | #define INIT_SCRIPT "/etc/init.d/rcS"
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[821] | 149 | #endif
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| 150 |
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[2725] | 151 | /* Each type of actions can appear many times. They will be
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| 152 | * handled in order. RESTART is an exception, only 1st is used.
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| 153 | */
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| 154 | /* Start these actions first and wait for completion */
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| 155 | #define SYSINIT 0x01
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| 156 | /* Start these after SYSINIT and wait for completion */
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| 157 | #define WAIT 0x02
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| 158 | /* Start these after WAIT and *dont* wait for completion */
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| 159 | #define ONCE 0x04
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| 160 | /*
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| 161 | * NB: while SYSINIT/WAIT/ONCE are being processed,
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| 162 | * SIGHUP ("reread /etc/inittab") will be processed only after
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| 163 | * each group of actions. If new inittab adds, say, a SYSINIT action,
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| 164 | * it will not be run, since init is already "past SYSINIT stage".
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| 165 | */
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| 166 | /* Start these after ONCE are started, restart on exit */
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| 167 | #define RESPAWN 0x08
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| 168 | /* Like RESPAWN, but wait for <Enter> to be pressed on tty */
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| 169 | #define ASKFIRST 0x10
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| 170 | /*
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| 171 | * Start these on SIGINT, and wait for completion.
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| 172 | * Then go back to respawning RESPAWN and ASKFIRST actions.
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| 173 | * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
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| 174 | */
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| 175 | #define CTRLALTDEL 0x20
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| 176 | /*
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| 177 | * Start these before killing all processes in preparation for
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| 178 | * running RESTART actions or doing low-level halt/reboot/poweroff
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| 179 | * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
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| 180 | * Wait for completion before proceeding.
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| 181 | */
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| 182 | #define SHUTDOWN 0x40
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| 183 | /*
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| 184 | * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
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| 185 | * then all processes are killed, then init exec's 1st RESTART action,
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| 186 | * replacing itself by it. If no RESTART action specified,
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| 187 | * SIGQUIT has no effect.
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| 188 | */
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| 189 | #define RESTART 0x80
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[821] | 190 |
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| 191 |
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[2725] | 192 | /* A linked list of init_actions, to be read from inittab */
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[821] | 193 | struct init_action {
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[1765] | 194 | struct init_action *next;
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[821] | 195 | pid_t pid;
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[2725] | 196 | uint8_t action_type;
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[1765] | 197 | char terminal[CONSOLE_NAME_SIZE];
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[2725] | 198 | char command[COMMAND_SIZE];
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[821] | 199 | };
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| 200 |
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| 201 | static struct init_action *init_action_list = NULL;
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| 202 |
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[1765] | 203 | static const char *log_console = VC_5;
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[821] | 204 |
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| 205 | enum {
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[1765] | 206 | L_LOG = 0x1,
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| 207 | L_CONSOLE = 0x2,
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[821] | 208 | };
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| 209 |
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| 210 | /* Print a message to the specified device.
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[2725] | 211 | * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
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| 212 | * NB: careful, we can be called after vfork!
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| 213 | */
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| 214 | #define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
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| 215 | static void message(int where, const char *fmt, ...)
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[821] | 216 | __attribute__ ((format(printf, 2, 3)));
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[2725] | 217 | static void message(int where, const char *fmt, ...)
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[821] | 218 | {
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[1765] | 219 | va_list arguments;
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[2725] | 220 | unsigned l;
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[1765] | 221 | char msg[128];
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| 222 |
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[821] | 223 | msg[0] = '\r';
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[1765] | 224 | va_start(arguments, fmt);
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[2725] | 225 | l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
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| 226 | if (l > sizeof(msg) - 1)
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| 227 | l = sizeof(msg) - 1;
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[1765] | 228 | va_end(arguments);
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[821] | 229 |
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[1765] | 230 | #if ENABLE_FEATURE_INIT_SYSLOG
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[2725] | 231 | msg[l] = '\0';
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| 232 | if (where & L_LOG) {
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| 233 | /* Log the message to syslogd */
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[1765] | 234 | openlog(applet_name, 0, LOG_DAEMON);
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[2725] | 235 | /* don't print "\r" */
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| 236 | syslog(LOG_INFO, "%s", msg + 1);
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[821] | 237 | closelog();
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| 238 | }
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| 239 | msg[l++] = '\n';
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[1765] | 240 | msg[l] = '\0';
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[821] | 241 | #else
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[2725] | 242 | {
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| 243 | static int log_fd = -1;
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| 244 |
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| 245 | msg[l++] = '\n';
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| 246 | msg[l] = '\0';
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| 247 | /* Take full control of the log tty, and never close it.
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| 248 | * It's mine, all mine! Muhahahaha! */
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| 249 | if (log_fd < 0) {
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| 250 | if (!log_console) {
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| 251 | log_fd = STDERR_FILENO;
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[1765] | 252 | } else {
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[2725] | 253 | log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
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| 254 | if (log_fd < 0) {
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| 255 | bb_error_msg("can't log to %s", log_console);
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| 256 | where = L_CONSOLE;
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| 257 | } else {
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| 258 | close_on_exec_on(log_fd);
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| 259 | }
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[1765] | 260 | }
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[821] | 261 | }
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[2725] | 262 | if (where & L_LOG) {
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| 263 | full_write(log_fd, msg, l);
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| 264 | if (log_fd == STDERR_FILENO)
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| 265 | return; /* don't print dup messages */
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| 266 | }
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[821] | 267 | }
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| 268 | #endif
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| 269 |
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[2725] | 270 | if (where & L_CONSOLE) {
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[1765] | 271 | /* Send console messages to console so people will see them. */
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[2725] | 272 | full_write(STDERR_FILENO, msg, l);
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[821] | 273 | }
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| 274 | }
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| 275 |
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[2725] | 276 | static void console_init(void)
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| 277 | {
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| 278 | #ifdef VT_OPENQRY
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| 279 | int vtno;
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| 280 | #endif
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| 281 | char *s;
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| 282 |
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| 283 | s = getenv("CONSOLE");
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| 284 | if (!s)
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| 285 | s = getenv("console");
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| 286 | if (s) {
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| 287 | int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
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| 288 | if (fd >= 0) {
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| 289 | dup2(fd, STDIN_FILENO);
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| 290 | dup2(fd, STDOUT_FILENO);
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| 291 | xmove_fd(fd, STDERR_FILENO);
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| 292 | }
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| 293 | dbg_message(L_LOG, "console='%s'", s);
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| 294 | } else {
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| 295 | /* Make sure fd 0,1,2 are not closed
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| 296 | * (so that they won't be used by future opens) */
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| 297 | bb_sanitize_stdio();
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| 298 | // Users report problems
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| 299 | // /* Make sure init can't be blocked by writing to stderr */
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| 300 | // fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
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| 301 | }
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| 302 |
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| 303 | s = getenv("TERM");
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| 304 | #ifdef VT_OPENQRY
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| 305 | if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
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| 306 | /* Not a linux terminal, probably serial console.
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| 307 | * Force the TERM setting to vt102
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| 308 | * if TERM is set to linux (the default) */
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| 309 | if (!s || strcmp(s, "linux") == 0)
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| 310 | putenv((char*)"TERM=vt102");
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| 311 | if (!ENABLE_FEATURE_INIT_SYSLOG)
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| 312 | log_console = NULL;
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| 313 | } else
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| 314 | #endif
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| 315 | if (!s)
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| 316 | putenv((char*)"TERM=" CONFIG_INIT_TERMINAL_TYPE);
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| 317 | }
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| 318 |
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| 319 | /* Set terminal settings to reasonable defaults.
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| 320 | * NB: careful, we can be called after vfork! */
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[1765] | 321 | static void set_sane_term(void)
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[821] | 322 | {
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| 323 | struct termios tty;
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| 324 |
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| 325 | tcgetattr(STDIN_FILENO, &tty);
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| 326 |
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| 327 | /* set control chars */
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| 328 | tty.c_cc[VINTR] = 3; /* C-c */
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| 329 | tty.c_cc[VQUIT] = 28; /* C-\ */
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| 330 | tty.c_cc[VERASE] = 127; /* C-? */
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| 331 | tty.c_cc[VKILL] = 21; /* C-u */
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| 332 | tty.c_cc[VEOF] = 4; /* C-d */
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| 333 | tty.c_cc[VSTART] = 17; /* C-q */
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| 334 | tty.c_cc[VSTOP] = 19; /* C-s */
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| 335 | tty.c_cc[VSUSP] = 26; /* C-z */
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| 336 |
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[2725] | 337 | #ifdef __linux__
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| 338 | /* use line discipline 0 */
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[821] | 339 | tty.c_line = 0;
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[2725] | 340 | #endif
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[821] | 341 |
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| 342 | /* Make it be sane */
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[2725] | 343 | #ifndef CRTSCTS
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| 344 | # define CRTSCTS 0
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| 345 | #endif
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| 346 | /* added CRTSCTS to fix Debian bug 528560 */
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| 347 | tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD | CRTSCTS;
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[821] | 348 | tty.c_cflag |= CREAD | HUPCL | CLOCAL;
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| 349 |
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| 350 | /* input modes */
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| 351 | tty.c_iflag = ICRNL | IXON | IXOFF;
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| 352 |
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| 353 | /* output modes */
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| 354 | tty.c_oflag = OPOST | ONLCR;
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| 355 |
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| 356 | /* local modes */
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[2725] | 357 | tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
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[821] | 358 |
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[2725] | 359 | tcsetattr_stdin_TCSANOW(&tty);
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[821] | 360 | }
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| 361 |
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[2725] | 362 | /* Open the new terminal device.
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| 363 | * NB: careful, we can be called after vfork! */
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| 364 | static int open_stdio_to_tty(const char* tty_name)
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[821] | 365 | {
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[1765] | 366 | /* empty tty_name means "use init's tty", else... */
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| 367 | if (tty_name[0]) {
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[2725] | 368 | int fd;
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| 369 |
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| 370 | close(STDIN_FILENO);
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| 371 | /* fd can be only < 0 or 0: */
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| 372 | fd = device_open(tty_name, O_RDWR);
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| 373 | if (fd) {
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| 374 | message(L_LOG | L_CONSOLE, "can't open %s: %s",
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[1765] | 375 | tty_name, strerror(errno));
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[2725] | 376 | return 0; /* failure */
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[1765] | 377 | }
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[2725] | 378 | dup2(STDIN_FILENO, STDOUT_FILENO);
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| 379 | dup2(STDIN_FILENO, STDERR_FILENO);
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[821] | 380 | }
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[1765] | 381 | set_sane_term();
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[2725] | 382 | return 1; /* success */
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[821] | 383 | }
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| 384 |
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[2725] | 385 | static void reset_sighandlers_and_unblock_sigs(void)
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[821] | 386 | {
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[2725] | 387 | bb_signals(0
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| 388 | + (1 << SIGUSR1)
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| 389 | + (1 << SIGUSR2)
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| 390 | + (1 << SIGTERM)
|
---|
| 391 | + (1 << SIGQUIT)
|
---|
| 392 | + (1 << SIGINT)
|
---|
| 393 | + (1 << SIGHUP)
|
---|
| 394 | + (1 << SIGTSTP)
|
---|
| 395 | + (1 << SIGSTOP)
|
---|
| 396 | , SIG_DFL);
|
---|
| 397 | sigprocmask_allsigs(SIG_UNBLOCK);
|
---|
| 398 | }
|
---|
[821] | 399 |
|
---|
[2725] | 400 | /* Wrapper around exec:
|
---|
| 401 | * Takes string (max COMMAND_SIZE chars).
|
---|
| 402 | * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
|
---|
| 403 | * Otherwise splits words on whitespace, deals with leading dash,
|
---|
| 404 | * and uses plain exec().
|
---|
| 405 | * NB: careful, we can be called after vfork!
|
---|
| 406 | */
|
---|
| 407 | static void init_exec(const char *command)
|
---|
| 408 | {
|
---|
| 409 | char *cmd[COMMAND_SIZE / 2];
|
---|
| 410 | char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
|
---|
| 411 | int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
|
---|
[821] | 412 |
|
---|
[3232] | 413 | command += dash;
|
---|
| 414 |
|
---|
[1765] | 415 | /* See if any special /bin/sh requiring characters are present */
|
---|
[2725] | 416 | if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
|
---|
[3232] | 417 | sprintf(buf, "exec %s", command); /* excluding "-" */
|
---|
[2725] | 418 | /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
|
---|
| 419 | cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
|
---|
[1765] | 420 | cmd[1] = (char*)"-c";
|
---|
[2725] | 421 | cmd[2] = buf;
|
---|
[1765] | 422 | cmd[3] = NULL;
|
---|
[3232] | 423 | command = LIBBB_DEFAULT_LOGIN_SHELL + 1;
|
---|
[1765] | 424 | } else {
|
---|
| 425 | /* Convert command (char*) into cmd (char**, one word per string) */
|
---|
[2725] | 426 | char *word, *next;
|
---|
| 427 | int i = 0;
|
---|
[3232] | 428 | next = strcpy(buf, command - dash); /* command including "-" */
|
---|
| 429 | command = next + dash;
|
---|
[2725] | 430 | while ((word = strsep(&next, " \t")) != NULL) {
|
---|
| 431 | if (*word != '\0') { /* not two spaces/tabs together? */
|
---|
| 432 | cmd[i] = word;
|
---|
[1765] | 433 | i++;
|
---|
[821] | 434 | }
|
---|
| 435 | }
|
---|
[1765] | 436 | cmd[i] = NULL;
|
---|
| 437 | }
|
---|
[2725] | 438 | /* If we saw leading "-", it is interactive shell.
|
---|
| 439 | * Try harder to give it a controlling tty.
|
---|
[3232] | 440 | */
|
---|
| 441 | if (ENABLE_FEATURE_INIT_SCTTY && dash) {
|
---|
[2725] | 442 | /* _Attempt_ to make stdin a controlling tty. */
|
---|
[3232] | 443 | ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
|
---|
[2725] | 444 | }
|
---|
[3232] | 445 | /* Here command never contains the dash, cmd[0] might */
|
---|
| 446 | BB_EXECVP(command, cmd);
|
---|
| 447 | message(L_LOG | L_CONSOLE, "can't run '%s': %s", command, strerror(errno));
|
---|
[2725] | 448 | /* returns if execvp fails */
|
---|
| 449 | }
|
---|
[821] | 450 |
|
---|
[2725] | 451 | /* Used only by run_actions */
|
---|
| 452 | static pid_t run(const struct init_action *a)
|
---|
| 453 | {
|
---|
| 454 | pid_t pid;
|
---|
[821] | 455 |
|
---|
[2725] | 456 | /* Careful: don't be affected by a signal in vforked child */
|
---|
| 457 | sigprocmask_allsigs(SIG_BLOCK);
|
---|
| 458 | if (BB_MMU && (a->action_type & ASKFIRST))
|
---|
| 459 | pid = fork();
|
---|
| 460 | else
|
---|
| 461 | pid = vfork();
|
---|
| 462 | if (pid < 0)
|
---|
| 463 | message(L_LOG | L_CONSOLE, "can't fork");
|
---|
| 464 | if (pid) {
|
---|
| 465 | sigprocmask_allsigs(SIG_UNBLOCK);
|
---|
| 466 | return pid; /* Parent or error */
|
---|
| 467 | }
|
---|
[821] | 468 |
|
---|
[2725] | 469 | /* Child */
|
---|
[821] | 470 |
|
---|
[2725] | 471 | /* Reset signal handlers that were set by the parent process */
|
---|
| 472 | reset_sighandlers_and_unblock_sigs();
|
---|
[821] | 473 |
|
---|
[2725] | 474 | /* Create a new session and make ourself the process group leader */
|
---|
| 475 | setsid();
|
---|
| 476 |
|
---|
| 477 | /* Open the new terminal device */
|
---|
| 478 | if (!open_stdio_to_tty(a->terminal))
|
---|
| 479 | _exit(EXIT_FAILURE);
|
---|
| 480 |
|
---|
| 481 | /* NB: on NOMMU we can't wait for input in child, so
|
---|
| 482 | * "askfirst" will work the same as "respawn". */
|
---|
| 483 | if (BB_MMU && (a->action_type & ASKFIRST)) {
|
---|
[1765] | 484 | static const char press_enter[] ALIGN1 =
|
---|
| 485 | #ifdef CUSTOMIZED_BANNER
|
---|
| 486 | #include CUSTOMIZED_BANNER
|
---|
[821] | 487 | #endif
|
---|
[1765] | 488 | "\nPlease press Enter to activate this console. ";
|
---|
| 489 | char c;
|
---|
| 490 | /*
|
---|
| 491 | * Save memory by not exec-ing anything large (like a shell)
|
---|
| 492 | * before the user wants it. This is critical if swap is not
|
---|
| 493 | * enabled and the system has low memory. Generally this will
|
---|
| 494 | * be run on the second virtual console, and the first will
|
---|
| 495 | * be allowed to start a shell or whatever an init script
|
---|
| 496 | * specifies.
|
---|
| 497 | */
|
---|
[2725] | 498 | dbg_message(L_LOG, "waiting for enter to start '%s'"
|
---|
[1765] | 499 | "(pid %d, tty '%s')\n",
|
---|
[2725] | 500 | a->command, getpid(), a->terminal);
|
---|
| 501 | full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
|
---|
| 502 | while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
|
---|
| 503 | continue;
|
---|
[1765] | 504 | }
|
---|
[821] | 505 |
|
---|
[2725] | 506 | /*
|
---|
| 507 | * When a file named /.init_enable_core exists, setrlimit is called
|
---|
| 508 | * before processes are spawned to set core file size as unlimited.
|
---|
| 509 | * This is for debugging only. Don't use this is production, unless
|
---|
| 510 | * you want core dumps lying about....
|
---|
| 511 | */
|
---|
| 512 | if (ENABLE_FEATURE_INIT_COREDUMPS) {
|
---|
| 513 | if (access("/.init_enable_core", F_OK) == 0) {
|
---|
[1765] | 514 | struct rlimit limit;
|
---|
| 515 | limit.rlim_cur = RLIM_INFINITY;
|
---|
| 516 | limit.rlim_max = RLIM_INFINITY;
|
---|
| 517 | setrlimit(RLIMIT_CORE, &limit);
|
---|
[821] | 518 | }
|
---|
[1765] | 519 | }
|
---|
[2725] | 520 |
|
---|
| 521 | /* Log the process name and args */
|
---|
| 522 | message(L_LOG, "starting pid %d, tty '%s': '%s'",
|
---|
[3232] | 523 | getpid(), a->terminal, a->command);
|
---|
[2725] | 524 |
|
---|
[1765] | 525 | /* Now run it. The new program will take over this PID,
|
---|
| 526 | * so nothing further in init.c should be run. */
|
---|
[2725] | 527 | init_exec(a->command);
|
---|
[1765] | 528 | /* We're still here? Some error happened. */
|
---|
| 529 | _exit(-1);
|
---|
[821] | 530 | }
|
---|
| 531 |
|
---|
[2725] | 532 | static struct init_action *mark_terminated(pid_t pid)
|
---|
[821] | 533 | {
|
---|
[2725] | 534 | struct init_action *a;
|
---|
[821] | 535 |
|
---|
[2725] | 536 | if (pid > 0) {
|
---|
[3232] | 537 | update_utmp(pid, DEAD_PROCESS,
|
---|
| 538 | /*tty_name:*/ NULL,
|
---|
| 539 | /*username:*/ NULL,
|
---|
| 540 | /*hostname:*/ NULL
|
---|
| 541 | );
|
---|
[2725] | 542 | for (a = init_action_list; a; a = a->next) {
|
---|
| 543 | if (a->pid == pid) {
|
---|
| 544 | a->pid = 0;
|
---|
| 545 | return a;
|
---|
| 546 | }
|
---|
| 547 | }
|
---|
| 548 | }
|
---|
| 549 | return NULL;
|
---|
| 550 | }
|
---|
| 551 |
|
---|
| 552 | static void waitfor(pid_t pid)
|
---|
| 553 | {
|
---|
| 554 | /* waitfor(run(x)): protect against failed fork inside run() */
|
---|
| 555 | if (pid <= 0)
|
---|
| 556 | return;
|
---|
| 557 |
|
---|
| 558 | /* Wait for any child (prevent zombies from exiting orphaned processes)
|
---|
| 559 | * but exit the loop only when specified one has exited. */
|
---|
[821] | 560 | while (1) {
|
---|
[2725] | 561 | pid_t wpid = wait(NULL);
|
---|
| 562 | mark_terminated(wpid);
|
---|
| 563 | /* Unsafe. SIGTSTP handler might have wait'ed it already */
|
---|
| 564 | /*if (wpid == pid) break;*/
|
---|
| 565 | /* More reliable: */
|
---|
| 566 | if (kill(pid, 0))
|
---|
[821] | 567 | break;
|
---|
[2725] | 568 | }
|
---|
| 569 | }
|
---|
| 570 |
|
---|
| 571 | /* Run all commands of a particular type */
|
---|
| 572 | static void run_actions(int action_type)
|
---|
| 573 | {
|
---|
| 574 | struct init_action *a;
|
---|
| 575 |
|
---|
| 576 | for (a = init_action_list; a; a = a->next) {
|
---|
| 577 | if (!(a->action_type & action_type))
|
---|
| 578 | continue;
|
---|
| 579 |
|
---|
| 580 | if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
|
---|
| 581 | pid_t pid = run(a);
|
---|
| 582 | if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
|
---|
| 583 | waitfor(pid);
|
---|
| 584 | }
|
---|
| 585 | if (a->action_type & (RESPAWN | ASKFIRST)) {
|
---|
| 586 | /* Only run stuff with pid == 0. If pid != 0,
|
---|
| 587 | * it is already running
|
---|
| 588 | */
|
---|
| 589 | if (a->pid == 0)
|
---|
| 590 | a->pid = run(a);
|
---|
| 591 | }
|
---|
| 592 | }
|
---|
| 593 | }
|
---|
| 594 |
|
---|
| 595 | static void new_init_action(uint8_t action_type, const char *command, const char *cons)
|
---|
| 596 | {
|
---|
| 597 | struct init_action *a, **nextp;
|
---|
| 598 |
|
---|
| 599 | /* Scenario:
|
---|
| 600 | * old inittab:
|
---|
| 601 | * ::shutdown:umount -a -r
|
---|
| 602 | * ::shutdown:swapoff -a
|
---|
| 603 | * new inittab:
|
---|
| 604 | * ::shutdown:swapoff -a
|
---|
| 605 | * ::shutdown:umount -a -r
|
---|
| 606 | * On reload, we must ensure entries end up in correct order.
|
---|
| 607 | * To achieve that, if we find a matching entry, we move it
|
---|
| 608 | * to the end.
|
---|
| 609 | */
|
---|
| 610 | nextp = &init_action_list;
|
---|
| 611 | while ((a = *nextp) != NULL) {
|
---|
[3232] | 612 | /* Don't enter action if it's already in the list.
|
---|
[2725] | 613 | * This prevents losing running RESPAWNs.
|
---|
| 614 | */
|
---|
| 615 | if (strcmp(a->command, command) == 0
|
---|
| 616 | && strcmp(a->terminal, cons) == 0
|
---|
| 617 | ) {
|
---|
| 618 | /* Remove from list */
|
---|
| 619 | *nextp = a->next;
|
---|
| 620 | /* Find the end of the list */
|
---|
| 621 | while (*nextp != NULL)
|
---|
| 622 | nextp = &(*nextp)->next;
|
---|
| 623 | a->next = NULL;
|
---|
[3232] | 624 | goto append;
|
---|
[821] | 625 | }
|
---|
[2725] | 626 | nextp = &a->next;
|
---|
[821] | 627 | }
|
---|
[2725] | 628 |
|
---|
[3232] | 629 | a = xzalloc(sizeof(*a));
|
---|
| 630 |
|
---|
[2725] | 631 | /* Append to the end of the list */
|
---|
[3232] | 632 | append:
|
---|
[2725] | 633 | *nextp = a;
|
---|
| 634 | a->action_type = action_type;
|
---|
| 635 | safe_strncpy(a->command, command, sizeof(a->command));
|
---|
| 636 | safe_strncpy(a->terminal, cons, sizeof(a->terminal));
|
---|
| 637 | dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
|
---|
| 638 | a->command, a->action_type, a->terminal);
|
---|
[821] | 639 | }
|
---|
| 640 |
|
---|
[2725] | 641 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
|
---|
| 642 | * then parse_inittab() simply adds in some default
|
---|
| 643 | * actions(i.e., runs INIT_SCRIPT and then starts a pair
|
---|
| 644 | * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
|
---|
| 645 | * _is_ defined, but /etc/inittab is missing, this
|
---|
| 646 | * results in the same set of default behaviors.
|
---|
| 647 | */
|
---|
| 648 | static void parse_inittab(void)
|
---|
[821] | 649 | {
|
---|
[2725] | 650 | #if ENABLE_FEATURE_USE_INITTAB
|
---|
| 651 | char *token[4];
|
---|
| 652 | parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
|
---|
[821] | 653 |
|
---|
[2725] | 654 | if (parser == NULL)
|
---|
| 655 | #endif
|
---|
| 656 | {
|
---|
| 657 | /* No inittab file - set up some default behavior */
|
---|
| 658 | /* Reboot on Ctrl-Alt-Del */
|
---|
| 659 | new_init_action(CTRLALTDEL, "reboot", "");
|
---|
| 660 | /* Umount all filesystems on halt/reboot */
|
---|
| 661 | new_init_action(SHUTDOWN, "umount -a -r", "");
|
---|
| 662 | /* Swapoff on halt/reboot */
|
---|
| 663 | if (ENABLE_SWAPONOFF)
|
---|
| 664 | new_init_action(SHUTDOWN, "swapoff -a", "");
|
---|
| 665 | /* Prepare to restart init when a QUIT is received */
|
---|
| 666 | new_init_action(RESTART, "init", "");
|
---|
| 667 | /* Askfirst shell on tty1-4 */
|
---|
| 668 | new_init_action(ASKFIRST, bb_default_login_shell, "");
|
---|
| 669 | //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
|
---|
| 670 | new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
|
---|
| 671 | new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
|
---|
| 672 | new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
|
---|
| 673 | /* sysinit */
|
---|
| 674 | new_init_action(SYSINIT, INIT_SCRIPT, "");
|
---|
| 675 | return;
|
---|
| 676 | }
|
---|
| 677 |
|
---|
| 678 | #if ENABLE_FEATURE_USE_INITTAB
|
---|
| 679 | /* optional_tty:ignored_runlevel:action:command
|
---|
| 680 | * Delims are not to be collapsed and need exactly 4 tokens
|
---|
| 681 | */
|
---|
| 682 | while (config_read(parser, token, 4, 0, "#:",
|
---|
| 683 | PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
|
---|
| 684 | /* order must correspond to SYSINIT..RESTART constants */
|
---|
| 685 | static const char actions[] ALIGN1 =
|
---|
| 686 | "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
|
---|
| 687 | "ctrlaltdel\0""shutdown\0""restart\0";
|
---|
| 688 | int action;
|
---|
| 689 | char *tty = token[0];
|
---|
| 690 |
|
---|
| 691 | if (!token[3]) /* less than 4 tokens */
|
---|
| 692 | goto bad_entry;
|
---|
| 693 | action = index_in_strings(actions, token[2]);
|
---|
| 694 | if (action < 0 || !token[3][0]) /* token[3]: command */
|
---|
| 695 | goto bad_entry;
|
---|
| 696 | /* turn .*TTY -> /dev/TTY */
|
---|
| 697 | if (tty[0]) {
|
---|
| 698 | tty = concat_path_file("/dev/", skip_dev_pfx(tty));
|
---|
[821] | 699 | }
|
---|
[2725] | 700 | new_init_action(1 << action, token[3], tty);
|
---|
| 701 | if (tty[0])
|
---|
| 702 | free(tty);
|
---|
| 703 | continue;
|
---|
| 704 | bad_entry:
|
---|
| 705 | message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
|
---|
| 706 | parser->lineno);
|
---|
[821] | 707 | }
|
---|
[2725] | 708 | config_close(parser);
|
---|
| 709 | #endif
|
---|
[821] | 710 | }
|
---|
| 711 |
|
---|
[2725] | 712 | static void pause_and_low_level_reboot(unsigned magic) NORETURN;
|
---|
| 713 | static void pause_and_low_level_reboot(unsigned magic)
|
---|
[821] | 714 | {
|
---|
| 715 | pid_t pid;
|
---|
[2725] | 716 |
|
---|
| 717 | /* Allow time for last message to reach serial console, etc */
|
---|
| 718 | sleep(1);
|
---|
| 719 |
|
---|
| 720 | /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
|
---|
| 721 | * in linux/kernel/sys.c, which can cause the machine to panic when
|
---|
| 722 | * the init process exits... */
|
---|
[1765] | 723 | pid = vfork();
|
---|
| 724 | if (pid == 0) { /* child */
|
---|
[821] | 725 | reboot(magic);
|
---|
[2725] | 726 | _exit(EXIT_SUCCESS);
|
---|
[821] | 727 | }
|
---|
[2725] | 728 | while (1)
|
---|
| 729 | sleep(1);
|
---|
[821] | 730 | }
|
---|
| 731 |
|
---|
[2725] | 732 | static void run_shutdown_and_kill_processes(void)
|
---|
[821] | 733 | {
|
---|
[2725] | 734 | /* Run everything to be run at "shutdown". This is done _prior_
|
---|
[821] | 735 | * to killing everything, in case people wish to use scripts to
|
---|
| 736 | * shut things down gracefully... */
|
---|
| 737 | run_actions(SHUTDOWN);
|
---|
| 738 |
|
---|
[1765] | 739 | message(L_CONSOLE | L_LOG, "The system is going down NOW!");
|
---|
| 740 |
|
---|
[821] | 741 | /* Send signals to every process _except_ pid 1 */
|
---|
| 742 | kill(-1, SIGTERM);
|
---|
[2725] | 743 | message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
|
---|
[1765] | 744 | sync();
|
---|
[821] | 745 | sleep(1);
|
---|
| 746 |
|
---|
| 747 | kill(-1, SIGKILL);
|
---|
[2725] | 748 | message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
|
---|
[1765] | 749 | sync();
|
---|
[2725] | 750 | /*sleep(1); - callers take care about making a pause */
|
---|
[821] | 751 | }
|
---|
| 752 |
|
---|
[2725] | 753 | /* Signal handling by init:
|
---|
| 754 | *
|
---|
| 755 | * For process with PID==1, on entry kernel sets all signals to SIG_DFL
|
---|
| 756 | * and unmasks all signals. However, for process with PID==1,
|
---|
| 757 | * default action (SIG_DFL) on any signal is to ignore it,
|
---|
| 758 | * even for special signals SIGKILL and SIGCONT.
|
---|
| 759 | * Also, any signal can be caught or blocked.
|
---|
| 760 | * (but SIGSTOP is still handled specially, at least in 2.6.20)
|
---|
| 761 | *
|
---|
| 762 | * We install two kinds of handlers, "immediate" and "delayed".
|
---|
| 763 | *
|
---|
| 764 | * Immediate handlers execute at any time, even while, say, sysinit
|
---|
| 765 | * is running.
|
---|
| 766 | *
|
---|
| 767 | * Delayed handlers just set a flag variable. The variable is checked
|
---|
| 768 | * in the main loop and acted upon.
|
---|
| 769 | *
|
---|
| 770 | * halt/poweroff/reboot and restart have immediate handlers.
|
---|
| 771 | * They only traverse linked list of struct action's, never modify it,
|
---|
| 772 | * this should be safe to do even in signal handler. Also they
|
---|
| 773 | * never return.
|
---|
| 774 | *
|
---|
| 775 | * SIGSTOP and SIGTSTP have immediate handlers. They just wait
|
---|
| 776 | * for SIGCONT to happen.
|
---|
| 777 | *
|
---|
| 778 | * SIGHUP has a delayed handler, because modifying linked list
|
---|
| 779 | * of struct action's from a signal handler while it is manipulated
|
---|
| 780 | * by the program may be disastrous.
|
---|
| 781 | *
|
---|
| 782 | * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
|
---|
| 783 | * it to happen even somewhere inside "sysinit" would be a bit awkward.
|
---|
| 784 | *
|
---|
| 785 | * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
|
---|
| 786 | * and only one will be remembered and acted upon.
|
---|
| 787 | */
|
---|
[821] | 788 |
|
---|
[2725] | 789 | /* The SIGUSR[12]/SIGTERM handler */
|
---|
| 790 | static void halt_reboot_pwoff(int sig) NORETURN;
|
---|
| 791 | static void halt_reboot_pwoff(int sig)
|
---|
[821] | 792 | {
|
---|
[1765] | 793 | const char *m;
|
---|
[2725] | 794 | unsigned rb;
|
---|
[821] | 795 |
|
---|
[2725] | 796 | /* We may call run() and it unmasks signals,
|
---|
| 797 | * including the one masked inside this signal handler.
|
---|
| 798 | * Testcase which would start multiple reboot scripts:
|
---|
| 799 | * while true; do reboot; done
|
---|
| 800 | * Preventing it:
|
---|
| 801 | */
|
---|
| 802 | reset_sighandlers_and_unblock_sigs();
|
---|
[821] | 803 |
|
---|
[2725] | 804 | run_shutdown_and_kill_processes();
|
---|
| 805 |
|
---|
[1765] | 806 | m = "halt";
|
---|
| 807 | rb = RB_HALT_SYSTEM;
|
---|
[821] | 808 | if (sig == SIGTERM) {
|
---|
| 809 | m = "reboot";
|
---|
| 810 | rb = RB_AUTOBOOT;
|
---|
| 811 | } else if (sig == SIGUSR2) {
|
---|
| 812 | m = "poweroff";
|
---|
| 813 | rb = RB_POWER_OFF;
|
---|
| 814 | }
|
---|
[2725] | 815 | message(L_CONSOLE, "Requesting system %s", m);
|
---|
| 816 | pause_and_low_level_reboot(rb);
|
---|
| 817 | /* not reached */
|
---|
[821] | 818 | }
|
---|
| 819 |
|
---|
[2725] | 820 | /* Handler for QUIT - exec "restart" action,
|
---|
| 821 | * else (no such action defined) do nothing */
|
---|
| 822 | static void restart_handler(int sig UNUSED_PARAM)
|
---|
[821] | 823 | {
|
---|
[2725] | 824 | struct init_action *a;
|
---|
[821] | 825 |
|
---|
[2725] | 826 | for (a = init_action_list; a; a = a->next) {
|
---|
| 827 | if (!(a->action_type & RESTART))
|
---|
| 828 | continue;
|
---|
[821] | 829 |
|
---|
[2725] | 830 | /* Starting from here, we won't return.
|
---|
| 831 | * Thus don't need to worry about preserving errno
|
---|
| 832 | * and such.
|
---|
| 833 | */
|
---|
[821] | 834 |
|
---|
[2725] | 835 | reset_sighandlers_and_unblock_sigs();
|
---|
[821] | 836 |
|
---|
[2725] | 837 | run_shutdown_and_kill_processes();
|
---|
[821] | 838 |
|
---|
[2725] | 839 | #ifdef RB_ENABLE_CAD
|
---|
| 840 | /* Allow Ctrl-Alt-Del to reboot the system.
|
---|
| 841 | * This is how kernel sets it up for init, we follow suit.
|
---|
| 842 | */
|
---|
| 843 | reboot(RB_ENABLE_CAD); /* misnomer */
|
---|
| 844 | #endif
|
---|
[821] | 845 |
|
---|
[2725] | 846 | if (open_stdio_to_tty(a->terminal)) {
|
---|
| 847 | dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
|
---|
| 848 | /* Theoretically should be safe.
|
---|
| 849 | * But in practice, kernel bugs may leave
|
---|
| 850 | * unkillable processes, and wait() may block forever.
|
---|
| 851 | * Oh well. Hoping "new" init won't be too surprised
|
---|
| 852 | * by having children it didn't create.
|
---|
| 853 | */
|
---|
| 854 | //while (wait(NULL) > 0)
|
---|
| 855 | // continue;
|
---|
| 856 | init_exec(a->command);
|
---|
[821] | 857 | }
|
---|
[2725] | 858 | /* Open or exec failed */
|
---|
| 859 | pause_and_low_level_reboot(RB_HALT_SYSTEM);
|
---|
| 860 | /* not reached */
|
---|
[821] | 861 | }
|
---|
| 862 | }
|
---|
| 863 |
|
---|
[2725] | 864 | /* The SIGSTOP/SIGTSTP handler
|
---|
| 865 | * NB: inside it, all signals except SIGCONT are masked
|
---|
| 866 | * via appropriate setup in sigaction().
|
---|
| 867 | */
|
---|
| 868 | static void stop_handler(int sig UNUSED_PARAM)
|
---|
[821] | 869 | {
|
---|
[2725] | 870 | smallint saved_bb_got_signal;
|
---|
| 871 | int saved_errno;
|
---|
[821] | 872 |
|
---|
[2725] | 873 | saved_bb_got_signal = bb_got_signal;
|
---|
| 874 | saved_errno = errno;
|
---|
| 875 | signal(SIGCONT, record_signo);
|
---|
| 876 |
|
---|
| 877 | while (1) {
|
---|
| 878 | pid_t wpid;
|
---|
| 879 |
|
---|
| 880 | if (bb_got_signal == SIGCONT)
|
---|
[821] | 881 | break;
|
---|
[2725] | 882 | /* NB: this can accidentally wait() for a process
|
---|
| 883 | * which we waitfor() elsewhere! waitfor() must have
|
---|
| 884 | * code which is resilient against this.
|
---|
| 885 | */
|
---|
| 886 | wpid = wait_any_nohang(NULL);
|
---|
| 887 | mark_terminated(wpid);
|
---|
| 888 | sleep(1);
|
---|
[821] | 889 | }
|
---|
[2725] | 890 |
|
---|
| 891 | signal(SIGCONT, SIG_DFL);
|
---|
| 892 | errno = saved_errno;
|
---|
| 893 | bb_got_signal = saved_bb_got_signal;
|
---|
[821] | 894 | }
|
---|
| 895 |
|
---|
[2725] | 896 | #if ENABLE_FEATURE_USE_INITTAB
|
---|
| 897 | static void reload_inittab(void)
|
---|
[821] | 898 | {
|
---|
[2725] | 899 | struct init_action *a, **nextp;
|
---|
[821] | 900 |
|
---|
[2725] | 901 | message(L_LOG, "reloading /etc/inittab");
|
---|
[821] | 902 |
|
---|
[2725] | 903 | /* Disable old entries */
|
---|
| 904 | for (a = init_action_list; a; a = a->next)
|
---|
| 905 | a->action_type = 0;
|
---|
[821] | 906 |
|
---|
[2725] | 907 | /* Append new entries, or modify existing entries
|
---|
| 908 | * (incl. setting a->action_type) if cmd and device name
|
---|
| 909 | * match new ones. End result: only entries with
|
---|
| 910 | * a->action_type == 0 are stale.
|
---|
| 911 | */
|
---|
| 912 | parse_inittab();
|
---|
[821] | 913 |
|
---|
[2725] | 914 | #if ENABLE_FEATURE_KILL_REMOVED
|
---|
| 915 | /* Kill stale entries */
|
---|
| 916 | /* Be nice and send SIGTERM first */
|
---|
| 917 | for (a = init_action_list; a; a = a->next)
|
---|
| 918 | if (a->action_type == 0 && a->pid != 0)
|
---|
| 919 | kill(a->pid, SIGTERM);
|
---|
| 920 | if (CONFIG_FEATURE_KILL_DELAY) {
|
---|
| 921 | /* NB: parent will wait in NOMMU case */
|
---|
| 922 | if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
|
---|
| 923 | sleep(CONFIG_FEATURE_KILL_DELAY);
|
---|
| 924 | for (a = init_action_list; a; a = a->next)
|
---|
| 925 | if (a->action_type == 0 && a->pid != 0)
|
---|
| 926 | kill(a->pid, SIGKILL);
|
---|
| 927 | _exit(EXIT_SUCCESS);
|
---|
[821] | 928 | }
|
---|
[2725] | 929 | }
|
---|
| 930 | #endif
|
---|
[821] | 931 |
|
---|
[2725] | 932 | /* Remove stale entries and SYSINIT entries.
|
---|
| 933 | * We never rerun SYSINIT entries anyway,
|
---|
| 934 | * removing them too saves a few bytes */
|
---|
| 935 | nextp = &init_action_list;
|
---|
| 936 | while ((a = *nextp) != NULL) {
|
---|
| 937 | if ((a->action_type & ~SYSINIT) == 0) {
|
---|
| 938 | *nextp = a->next;
|
---|
| 939 | free(a);
|
---|
[821] | 940 | } else {
|
---|
[2725] | 941 | nextp = &a->next;
|
---|
[821] | 942 | }
|
---|
[2725] | 943 | }
|
---|
[821] | 944 |
|
---|
[2725] | 945 | /* Not needed: */
|
---|
| 946 | /* run_actions(RESPAWN | ASKFIRST); */
|
---|
| 947 | /* - we return to main loop, which does this automagically */
|
---|
[821] | 948 | }
|
---|
[2725] | 949 | #endif
|
---|
[821] | 950 |
|
---|
[2725] | 951 | static int check_delayed_sigs(void)
|
---|
[821] | 952 | {
|
---|
[2725] | 953 | int sigs_seen = 0;
|
---|
[821] | 954 |
|
---|
[2725] | 955 | while (1) {
|
---|
| 956 | smallint sig = bb_got_signal;
|
---|
[821] | 957 |
|
---|
[2725] | 958 | if (!sig)
|
---|
| 959 | return sigs_seen;
|
---|
| 960 | bb_got_signal = 0;
|
---|
| 961 | sigs_seen = 1;
|
---|
| 962 | #if ENABLE_FEATURE_USE_INITTAB
|
---|
| 963 | if (sig == SIGHUP)
|
---|
| 964 | reload_inittab();
|
---|
| 965 | #endif
|
---|
| 966 | if (sig == SIGINT)
|
---|
| 967 | run_actions(CTRLALTDEL);
|
---|
[821] | 968 | }
|
---|
| 969 | }
|
---|
| 970 |
|
---|
[3232] | 971 | #if DEBUG_SEGV_HANDLER
|
---|
| 972 | static
|
---|
| 973 | void handle_sigsegv(int sig, siginfo_t *info, void *ucontext)
|
---|
| 974 | {
|
---|
| 975 | long ip;
|
---|
| 976 | ucontext_t *uc;
|
---|
| 977 |
|
---|
| 978 | uc = ucontext;
|
---|
| 979 | ip = uc->uc_mcontext.gregs[REG_EIP];
|
---|
| 980 | fdprintf(2, "signal:%d address:0x%lx ip:0x%lx\n",
|
---|
| 981 | sig,
|
---|
| 982 | /* this is void*, but using %p would print "(null)"
|
---|
| 983 | * even for ptrs which are not exactly 0, but, say, 0x123:
|
---|
| 984 | */
|
---|
| 985 | (long)info->si_addr,
|
---|
| 986 | ip);
|
---|
| 987 | {
|
---|
| 988 | /* glibc extension */
|
---|
| 989 | void *array[50];
|
---|
| 990 | int size;
|
---|
| 991 | size = backtrace(array, 50);
|
---|
| 992 | backtrace_symbols_fd(array, size, 2);
|
---|
| 993 | }
|
---|
| 994 | for (;;) sleep(9999);
|
---|
| 995 | }
|
---|
| 996 | #endif
|
---|
| 997 |
|
---|
[2725] | 998 | int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 999 | int init_main(int argc UNUSED_PARAM, char **argv)
|
---|
[821] | 1000 | {
|
---|
[2725] | 1001 | if (argv[1] && strcmp(argv[1], "-q") == 0) {
|
---|
[1765] | 1002 | return kill(1, SIGHUP);
|
---|
[821] | 1003 | }
|
---|
| 1004 |
|
---|
[3232] | 1005 | #if DEBUG_SEGV_HANDLER
|
---|
| 1006 | {
|
---|
| 1007 | struct sigaction sa;
|
---|
| 1008 | memset(&sa, 0, sizeof(sa));
|
---|
| 1009 | sa.sa_sigaction = handle_sigsegv;
|
---|
| 1010 | sa.sa_flags = SA_SIGINFO;
|
---|
| 1011 | sigaction(SIGSEGV, &sa, NULL);
|
---|
| 1012 | sigaction(SIGILL, &sa, NULL);
|
---|
| 1013 | sigaction(SIGFPE, &sa, NULL);
|
---|
| 1014 | sigaction(SIGBUS, &sa, NULL);
|
---|
| 1015 | }
|
---|
| 1016 | #endif
|
---|
| 1017 |
|
---|
[2725] | 1018 | if (!DEBUG_INIT) {
|
---|
| 1019 | /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
|
---|
| 1020 | if (getpid() != 1
|
---|
| 1021 | && (!ENABLE_FEATURE_INITRD || applet_name[0] != 'l') /* not linuxrc? */
|
---|
| 1022 | ) {
|
---|
| 1023 | bb_error_msg_and_die("must be run as PID 1");
|
---|
| 1024 | }
|
---|
| 1025 | #ifdef RB_DISABLE_CAD
|
---|
| 1026 | /* Turn off rebooting via CTL-ALT-DEL - we get a
|
---|
| 1027 | * SIGINT on CAD so we can shut things down gracefully... */
|
---|
| 1028 | reboot(RB_DISABLE_CAD); /* misnomer */
|
---|
[821] | 1029 | #endif
|
---|
[2725] | 1030 | }
|
---|
[821] | 1031 |
|
---|
[2725] | 1032 | /* If, say, xmalloc would ever die, we don't want to oops kernel
|
---|
| 1033 | * by exiting.
|
---|
| 1034 | * NB: we set die_sleep *after* PID 1 check and bb_show_usage.
|
---|
| 1035 | * Otherwise, for example, "init u" ("please rexec yourself"
|
---|
| 1036 | * command for sysvinit) will show help text (which isn't too bad),
|
---|
| 1037 | * *and sleep forever* (which is bad!)
|
---|
| 1038 | */
|
---|
| 1039 | die_sleep = 30 * 24*60*60;
|
---|
[1765] | 1040 |
|
---|
[821] | 1041 | /* Figure out where the default console should be */
|
---|
| 1042 | console_init();
|
---|
[1765] | 1043 | set_sane_term();
|
---|
[2725] | 1044 | xchdir("/");
|
---|
[821] | 1045 | setsid();
|
---|
[1765] | 1046 |
|
---|
[2725] | 1047 | /* Make sure environs is set to something sane */
|
---|
| 1048 | putenv((char *) "HOME=/");
|
---|
| 1049 | putenv((char *) bb_PATH_root_path);
|
---|
| 1050 | putenv((char *) "SHELL=/bin/sh");
|
---|
| 1051 | putenv((char *) "USER=root"); /* needed? why? */
|
---|
[1765] | 1052 |
|
---|
[2725] | 1053 | if (argv[1])
|
---|
| 1054 | xsetenv("RUNLEVEL", argv[1]);
|
---|
| 1055 |
|
---|
| 1056 | #if !ENABLE_FEATURE_EXTRA_QUIET
|
---|
[821] | 1057 | /* Hello world */
|
---|
[2725] | 1058 | message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
|
---|
| 1059 | #endif
|
---|
[821] | 1060 |
|
---|
[2725] | 1061 | /* struct sysinfo is linux-specific */
|
---|
| 1062 | #ifdef __linux__
|
---|
[821] | 1063 | /* Make sure there is enough memory to do something useful. */
|
---|
| 1064 | if (ENABLE_SWAPONOFF) {
|
---|
| 1065 | struct sysinfo info;
|
---|
| 1066 |
|
---|
[2725] | 1067 | if (sysinfo(&info) == 0
|
---|
| 1068 | && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024
|
---|
| 1069 | ) {
|
---|
[1765] | 1070 | message(L_CONSOLE, "Low memory, forcing swapon");
|
---|
[821] | 1071 | /* swapon -a requires /proc typically */
|
---|
[1765] | 1072 | new_init_action(SYSINIT, "mount -t proc proc /proc", "");
|
---|
[821] | 1073 | /* Try to turn on swap */
|
---|
[1765] | 1074 | new_init_action(SYSINIT, "swapon -a", "");
|
---|
[821] | 1075 | run_actions(SYSINIT); /* wait and removing */
|
---|
| 1076 | }
|
---|
| 1077 | }
|
---|
[2725] | 1078 | #endif
|
---|
[821] | 1079 |
|
---|
| 1080 | /* Check if we are supposed to be in single user mode */
|
---|
[2725] | 1081 | if (argv[1]
|
---|
| 1082 | && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1'))
|
---|
[1765] | 1083 | ) {
|
---|
[2725] | 1084 | /* ??? shouldn't we set RUNLEVEL="b" here? */
|
---|
[821] | 1085 | /* Start a shell on console */
|
---|
| 1086 | new_init_action(RESPAWN, bb_default_login_shell, "");
|
---|
| 1087 | } else {
|
---|
[2725] | 1088 | /* Not in single user mode - see what inittab says */
|
---|
[821] | 1089 |
|
---|
| 1090 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
|
---|
| 1091 | * then parse_inittab() simply adds in some default
|
---|
[2725] | 1092 | * actions(i.e., INIT_SCRIPT and a pair
|
---|
[821] | 1093 | * of "askfirst" shells */
|
---|
| 1094 | parse_inittab();
|
---|
| 1095 | }
|
---|
| 1096 |
|
---|
[1765] | 1097 | #if ENABLE_SELINUX
|
---|
[821] | 1098 | if (getenv("SELINUX_INIT") == NULL) {
|
---|
| 1099 | int enforce = 0;
|
---|
| 1100 |
|
---|
[1765] | 1101 | putenv((char*)"SELINUX_INIT=YES");
|
---|
[821] | 1102 | if (selinux_init_load_policy(&enforce) == 0) {
|
---|
[1765] | 1103 | BB_EXECVP(argv[0], argv);
|
---|
[821] | 1104 | } else if (enforce > 0) {
|
---|
| 1105 | /* SELinux in enforcing mode but load_policy failed */
|
---|
[2725] | 1106 | message(L_CONSOLE, "can't load SELinux Policy. "
|
---|
[1765] | 1107 | "Machine is in enforcing mode. Halting now.");
|
---|
[2725] | 1108 | return EXIT_FAILURE;
|
---|
[821] | 1109 | }
|
---|
| 1110 | }
|
---|
[2725] | 1111 | #endif
|
---|
[821] | 1112 |
|
---|
[2725] | 1113 | /* Make the command line just say "init" - thats all, nothing else */
|
---|
| 1114 | strncpy(argv[0], "init", strlen(argv[0]));
|
---|
| 1115 | /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
|
---|
| 1116 | while (*++argv)
|
---|
| 1117 | memset(*argv, 0, strlen(*argv));
|
---|
[821] | 1118 |
|
---|
[2725] | 1119 | /* Set up signal handlers */
|
---|
| 1120 | if (!DEBUG_INIT) {
|
---|
| 1121 | struct sigaction sa;
|
---|
| 1122 |
|
---|
| 1123 | bb_signals(0
|
---|
| 1124 | + (1 << SIGUSR1) /* halt */
|
---|
| 1125 | + (1 << SIGTERM) /* reboot */
|
---|
| 1126 | + (1 << SIGUSR2) /* poweroff */
|
---|
| 1127 | , halt_reboot_pwoff);
|
---|
| 1128 | signal(SIGQUIT, restart_handler); /* re-exec another init */
|
---|
| 1129 |
|
---|
| 1130 | /* Stop handler must allow only SIGCONT inside itself */
|
---|
| 1131 | memset(&sa, 0, sizeof(sa));
|
---|
| 1132 | sigfillset(&sa.sa_mask);
|
---|
| 1133 | sigdelset(&sa.sa_mask, SIGCONT);
|
---|
| 1134 | sa.sa_handler = stop_handler;
|
---|
| 1135 | /* NB: sa_flags doesn't have SA_RESTART.
|
---|
| 1136 | * It must be able to interrupt wait().
|
---|
| 1137 | */
|
---|
| 1138 | sigaction_set(SIGTSTP, &sa); /* pause */
|
---|
| 1139 | /* Does not work as intended, at least in 2.6.20.
|
---|
| 1140 | * SIGSTOP is simply ignored by init:
|
---|
| 1141 | */
|
---|
| 1142 | sigaction_set(SIGSTOP, &sa); /* pause */
|
---|
| 1143 |
|
---|
| 1144 | /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
|
---|
| 1145 | * setting handler without SA_RESTART flag.
|
---|
| 1146 | */
|
---|
| 1147 | bb_signals_recursive_norestart((1 << SIGINT), record_signo);
|
---|
| 1148 | }
|
---|
| 1149 |
|
---|
| 1150 | /* Set up "reread /etc/inittab" handler.
|
---|
| 1151 | * Handler is set up without SA_RESTART, it will interrupt syscalls.
|
---|
| 1152 | */
|
---|
| 1153 | if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
|
---|
| 1154 | bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
|
---|
| 1155 |
|
---|
[821] | 1156 | /* Now run everything that needs to be run */
|
---|
| 1157 | /* First run the sysinit command */
|
---|
| 1158 | run_actions(SYSINIT);
|
---|
[2725] | 1159 | check_delayed_sigs();
|
---|
[821] | 1160 | /* Next run anything that wants to block */
|
---|
| 1161 | run_actions(WAIT);
|
---|
[2725] | 1162 | check_delayed_sigs();
|
---|
[821] | 1163 | /* Next run anything to be run only once */
|
---|
| 1164 | run_actions(ONCE);
|
---|
| 1165 |
|
---|
[2725] | 1166 | /* Now run the looping stuff for the rest of forever.
|
---|
| 1167 | */
|
---|
[821] | 1168 | while (1) {
|
---|
[2725] | 1169 | int maybe_WNOHANG;
|
---|
[821] | 1170 |
|
---|
[2725] | 1171 | maybe_WNOHANG = check_delayed_sigs();
|
---|
[821] | 1172 |
|
---|
[2725] | 1173 | /* (Re)run the respawn/askfirst stuff */
|
---|
| 1174 | run_actions(RESPAWN | ASKFIRST);
|
---|
| 1175 | maybe_WNOHANG |= check_delayed_sigs();
|
---|
| 1176 |
|
---|
| 1177 | /* Don't consume all CPU time - sleep a bit */
|
---|
[821] | 1178 | sleep(1);
|
---|
[2725] | 1179 | maybe_WNOHANG |= check_delayed_sigs();
|
---|
[821] | 1180 |
|
---|
[2725] | 1181 | /* Wait for any child process(es) to exit.
|
---|
| 1182 | *
|
---|
| 1183 | * If check_delayed_sigs above reported that a signal
|
---|
| 1184 | * was caught, wait will be nonblocking. This ensures
|
---|
| 1185 | * that if SIGHUP has reloaded inittab, respawn and askfirst
|
---|
| 1186 | * actions will not be delayed until next child death.
|
---|
| 1187 | */
|
---|
| 1188 | if (maybe_WNOHANG)
|
---|
| 1189 | maybe_WNOHANG = WNOHANG;
|
---|
| 1190 | while (1) {
|
---|
| 1191 | pid_t wpid;
|
---|
| 1192 | struct init_action *a;
|
---|
| 1193 |
|
---|
| 1194 | /* If signals happen _in_ the wait, they interrupt it,
|
---|
| 1195 | * bb_signals_recursive_norestart set them up that way
|
---|
| 1196 | */
|
---|
| 1197 | wpid = waitpid(-1, NULL, maybe_WNOHANG);
|
---|
| 1198 | if (wpid <= 0)
|
---|
| 1199 | break;
|
---|
| 1200 |
|
---|
| 1201 | a = mark_terminated(wpid);
|
---|
| 1202 | if (a) {
|
---|
| 1203 | message(L_LOG, "process '%s' (pid %d) exited. "
|
---|
| 1204 | "Scheduling for restart.",
|
---|
| 1205 | a->command, wpid);
|
---|
[821] | 1206 | }
|
---|
[2725] | 1207 | /* See if anyone else is waiting to be reaped */
|
---|
| 1208 | maybe_WNOHANG = WNOHANG;
|
---|
[821] | 1209 | }
|
---|
[2725] | 1210 | } /* while (1) */
|
---|
[821] | 1211 | }
|
---|
[2725] | 1212 |
|
---|
| 1213 | //usage:#define linuxrc_trivial_usage NOUSAGE_STR
|
---|
| 1214 | //usage:#define linuxrc_full_usage ""
|
---|
| 1215 |
|
---|
| 1216 | //usage:#define init_trivial_usage
|
---|
| 1217 | //usage: ""
|
---|
| 1218 | //usage:#define init_full_usage "\n\n"
|
---|
| 1219 | //usage: "Init is the parent of all processes"
|
---|
| 1220 | //usage:
|
---|
| 1221 | //usage:#define init_notes_usage
|
---|
| 1222 | //usage: "This version of init is designed to be run only by the kernel.\n"
|
---|
| 1223 | //usage: "\n"
|
---|
| 1224 | //usage: "BusyBox init doesn't support multiple runlevels. The runlevels field of\n"
|
---|
| 1225 | //usage: "the /etc/inittab file is completely ignored by BusyBox init. If you want\n"
|
---|
| 1226 | //usage: "runlevels, use sysvinit.\n"
|
---|
| 1227 | //usage: "\n"
|
---|
| 1228 | //usage: "BusyBox init works just fine without an inittab. If no inittab is found,\n"
|
---|
| 1229 | //usage: "it has the following default behavior:\n"
|
---|
| 1230 | //usage: "\n"
|
---|
| 1231 | //usage: " ::sysinit:/etc/init.d/rcS\n"
|
---|
| 1232 | //usage: " ::askfirst:/bin/sh\n"
|
---|
| 1233 | //usage: " ::ctrlaltdel:/sbin/reboot\n"
|
---|
| 1234 | //usage: " ::shutdown:/sbin/swapoff -a\n"
|
---|
| 1235 | //usage: " ::shutdown:/bin/umount -a -r\n"
|
---|
| 1236 | //usage: " ::restart:/sbin/init\n"
|
---|
| 1237 | //usage: "\n"
|
---|
| 1238 | //usage: "if it detects that /dev/console is _not_ a serial console, it will also run:\n"
|
---|
| 1239 | //usage: "\n"
|
---|
| 1240 | //usage: " tty2::askfirst:/bin/sh\n"
|
---|
| 1241 | //usage: " tty3::askfirst:/bin/sh\n"
|
---|
| 1242 | //usage: " tty4::askfirst:/bin/sh\n"
|
---|
| 1243 | //usage: "\n"
|
---|
| 1244 | //usage: "If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n"
|
---|
| 1245 | //usage: "\n"
|
---|
| 1246 | //usage: " <id>:<runlevels>:<action>:<process>\n"
|
---|
| 1247 | //usage: "\n"
|
---|
| 1248 | //usage: " <id>:\n"
|
---|
| 1249 | //usage: "\n"
|
---|
| 1250 | //usage: " WARNING: This field has a non-traditional meaning for BusyBox init!\n"
|
---|
| 1251 | //usage: " The id field is used by BusyBox init to specify the controlling tty for\n"
|
---|
| 1252 | //usage: " the specified process to run on. The contents of this field are\n"
|
---|
| 1253 | //usage: " appended to \"/dev/\" and used as-is. There is no need for this field to\n"
|
---|
| 1254 | //usage: " be unique, although if it isn't you may have strange results. If this\n"
|
---|
| 1255 | //usage: " field is left blank, the controlling tty is set to the console. Also\n"
|
---|
| 1256 | //usage: " note that if BusyBox detects that a serial console is in use, then only\n"
|
---|
| 1257 | //usage: " entries whose controlling tty is either the serial console or /dev/null\n"
|
---|
| 1258 | //usage: " will be run. BusyBox init does nothing with utmp. We don't need no\n"
|
---|
| 1259 | //usage: " stinkin' utmp.\n"
|
---|
| 1260 | //usage: "\n"
|
---|
| 1261 | //usage: " <runlevels>:\n"
|
---|
| 1262 | //usage: "\n"
|
---|
| 1263 | //usage: " The runlevels field is completely ignored.\n"
|
---|
| 1264 | //usage: "\n"
|
---|
| 1265 | //usage: " <action>:\n"
|
---|
| 1266 | //usage: "\n"
|
---|
| 1267 | //usage: " Valid actions include: sysinit, respawn, askfirst, wait,\n"
|
---|
| 1268 | //usage: " once, restart, ctrlaltdel, and shutdown.\n"
|
---|
| 1269 | //usage: "\n"
|
---|
| 1270 | //usage: " The available actions can be classified into two groups: actions\n"
|
---|
| 1271 | //usage: " that are run only once, and actions that are re-run when the specified\n"
|
---|
| 1272 | //usage: " process exits.\n"
|
---|
| 1273 | //usage: "\n"
|
---|
| 1274 | //usage: " Run only-once actions:\n"
|
---|
| 1275 | //usage: "\n"
|
---|
| 1276 | //usage: " 'sysinit' is the first item run on boot. init waits until all\n"
|
---|
| 1277 | //usage: " sysinit actions are completed before continuing. Following the\n"
|
---|
| 1278 | //usage: " completion of all sysinit actions, all 'wait' actions are run.\n"
|
---|
| 1279 | //usage: " 'wait' actions, like 'sysinit' actions, cause init to wait until\n"
|
---|
| 1280 | //usage: " the specified task completes. 'once' actions are asynchronous,\n"
|
---|
| 1281 | //usage: " therefore, init does not wait for them to complete. 'restart' is\n"
|
---|
| 1282 | //usage: " the action taken to restart the init process. By default this should\n"
|
---|
| 1283 | //usage: " simply run /sbin/init, but can be a script which runs pivot_root or it\n"
|
---|
| 1284 | //usage: " can do all sorts of other interesting things. The 'ctrlaltdel' init\n"
|
---|
| 1285 | //usage: " actions are run when the system detects that someone on the system\n"
|
---|
| 1286 | //usage: " console has pressed the CTRL-ALT-DEL key combination. Typically one\n"
|
---|
| 1287 | //usage: " wants to run 'reboot' at this point to cause the system to reboot.\n"
|
---|
| 1288 | //usage: " Finally the 'shutdown' action specifies the actions to taken when\n"
|
---|
| 1289 | //usage: " init is told to reboot. Unmounting filesystems and disabling swap\n"
|
---|
| 1290 | //usage: " is a very good here.\n"
|
---|
| 1291 | //usage: "\n"
|
---|
| 1292 | //usage: " Run repeatedly actions:\n"
|
---|
| 1293 | //usage: "\n"
|
---|
| 1294 | //usage: " 'respawn' actions are run after the 'once' actions. When a process\n"
|
---|
| 1295 | //usage: " started with a 'respawn' action exits, init automatically restarts\n"
|
---|
| 1296 | //usage: " it. Unlike sysvinit, BusyBox init does not stop processes from\n"
|
---|
| 1297 | //usage: " respawning out of control. The 'askfirst' actions acts just like\n"
|
---|
| 1298 | //usage: " respawn, except that before running the specified process it\n"
|
---|
| 1299 | //usage: " displays the line \"Please press Enter to activate this console.\"\n"
|
---|
| 1300 | //usage: " and then waits for the user to press enter before starting the\n"
|
---|
| 1301 | //usage: " specified process.\n"
|
---|
| 1302 | //usage: "\n"
|
---|
| 1303 | //usage: " Unrecognized actions (like initdefault) will cause init to emit an\n"
|
---|
| 1304 | //usage: " error message, and then go along with its business. All actions are\n"
|
---|
| 1305 | //usage: " run in the order they appear in /etc/inittab.\n"
|
---|
| 1306 | //usage: "\n"
|
---|
| 1307 | //usage: " <process>:\n"
|
---|
| 1308 | //usage: "\n"
|
---|
| 1309 | //usage: " Specifies the process to be executed and its command line.\n"
|
---|
| 1310 | //usage: "\n"
|
---|
| 1311 | //usage: "Example /etc/inittab file:\n"
|
---|
| 1312 | //usage: "\n"
|
---|
| 1313 | //usage: " # This is run first except when booting in single-user mode\n"
|
---|
| 1314 | //usage: " #\n"
|
---|
| 1315 | //usage: " ::sysinit:/etc/init.d/rcS\n"
|
---|
| 1316 | //usage: " \n"
|
---|
| 1317 | //usage: " # /bin/sh invocations on selected ttys\n"
|
---|
| 1318 | //usage: " #\n"
|
---|
| 1319 | //usage: " # Start an \"askfirst\" shell on the console (whatever that may be)\n"
|
---|
| 1320 | //usage: " ::askfirst:-/bin/sh\n"
|
---|
| 1321 | //usage: " # Start an \"askfirst\" shell on /dev/tty2-4\n"
|
---|
| 1322 | //usage: " tty2::askfirst:-/bin/sh\n"
|
---|
| 1323 | //usage: " tty3::askfirst:-/bin/sh\n"
|
---|
| 1324 | //usage: " tty4::askfirst:-/bin/sh\n"
|
---|
| 1325 | //usage: " \n"
|
---|
| 1326 | //usage: " # /sbin/getty invocations for selected ttys\n"
|
---|
| 1327 | //usage: " #\n"
|
---|
| 1328 | //usage: " tty4::respawn:/sbin/getty 38400 tty4\n"
|
---|
| 1329 | //usage: " tty5::respawn:/sbin/getty 38400 tty5\n"
|
---|
| 1330 | //usage: " \n"
|
---|
| 1331 | //usage: " \n"
|
---|
| 1332 | //usage: " # Example of how to put a getty on a serial line (for a terminal)\n"
|
---|
| 1333 | //usage: " #\n"
|
---|
| 1334 | //usage: " #::respawn:/sbin/getty -L ttyS0 9600 vt100\n"
|
---|
| 1335 | //usage: " #::respawn:/sbin/getty -L ttyS1 9600 vt100\n"
|
---|
| 1336 | //usage: " #\n"
|
---|
| 1337 | //usage: " # Example how to put a getty on a modem line\n"
|
---|
| 1338 | //usage: " #::respawn:/sbin/getty 57600 ttyS2\n"
|
---|
| 1339 | //usage: " \n"
|
---|
| 1340 | //usage: " # Stuff to do when restarting the init process\n"
|
---|
| 1341 | //usage: " ::restart:/sbin/init\n"
|
---|
| 1342 | //usage: " \n"
|
---|
| 1343 | //usage: " # Stuff to do before rebooting\n"
|
---|
| 1344 | //usage: " ::ctrlaltdel:/sbin/reboot\n"
|
---|
| 1345 | //usage: " ::shutdown:/bin/umount -a -r\n"
|
---|
| 1346 | //usage: " ::shutdown:/sbin/swapoff -a\n"
|
---|