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);
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389 | }
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390 |
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391 | /* Wrapper around exec:
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392 | * Takes string (max COMMAND_SIZE chars).
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393 | * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
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394 | * Otherwise splits words on whitespace, deals with leading dash,
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395 | * and uses plain exec().
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396 | * NB: careful, we can be called after vfork!
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397 | */
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398 | static void init_exec(const char *command)
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399 | {
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400 | char *cmd[COMMAND_SIZE / 2];
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401 | char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
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402 | int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
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403 |
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404 | /* See if any special /bin/sh requiring characters are present */
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405 | if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
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406 | strcpy(buf, "exec ");
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407 | strcpy(buf + 5, command + dash); /* excluding "-" */
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408 | /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
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409 | cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
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410 | cmd[1] = (char*)"-c";
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411 | cmd[2] = buf;
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412 | cmd[3] = NULL;
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413 | } else {
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414 | /* Convert command (char*) into cmd (char**, one word per string) */
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415 | char *word, *next;
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416 | int i = 0;
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417 | next = strcpy(buf, command); /* including "-" */
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418 | while ((word = strsep(&next, " \t")) != NULL) {
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419 | if (*word != '\0') { /* not two spaces/tabs together? */
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420 | cmd[i] = word;
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421 | i++;
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422 | }
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423 | }
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424 | cmd[i] = NULL;
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425 | }
|
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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"
|
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1257 | //usage: "\n"
|
---|
1258 | //usage: " # This is run first except when booting in single-user mode\n"
|
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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"
|
---|