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