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Diffstat (limited to 'init/init.c')
| -rw-r--r-- | init/init.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/init/init.c b/init/init.c index 5c0d114..340731b 100644 --- a/init/init.c +++ b/init/init.c @@ -9,6 +9,237 @@ * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ +//applet:IF_INIT(APPLET(init, _BB_DIR_SBIN, _BB_SUID_DROP)) +//applet:IF_FEATURE_INITRD(APPLET_ODDNAME(linuxrc, init, _BB_DIR_ROOT, _BB_SUID_DROP, linuxrc)) + +//kbuild:lib-$(CONFIG_INIT) += init.o + +//config:config INIT +//config: bool "init" +//config: default y +//config: select FEATURE_SYSLOG +//config: help +//config: init is the first program run when the system boots. +//config: +//config:config FEATURE_USE_INITTAB +//config: bool "Support reading an inittab file" +//config: default y +//config: depends on INIT +//config: help +//config: Allow init to read an inittab file when the system boot. +//config: +//config:config FEATURE_KILL_REMOVED +//config: bool "Support killing processes that have been removed from inittab" +//config: default n +//config: depends on FEATURE_USE_INITTAB +//config: help +//config: When respawn entries are removed from inittab and a SIGHUP is +//config: sent to init, this option will make init kill the processes +//config: that have been removed. +//config: +//config:config FEATURE_KILL_DELAY +//config: int "How long to wait between TERM and KILL (0 - send TERM only)" if FEATURE_KILL_REMOVED +//config: range 0 1024 +//config: default 0 +//config: depends on FEATURE_KILL_REMOVED +//config: help +//config: With nonzero setting, init sends TERM, forks, child waits N +//config: seconds, sends KILL and exits. Setting it too high is unwise +//config: (child will hang around for too long and could actually kill +//config: the wrong process!) +//config: +//config:config FEATURE_INIT_SCTTY +//config: bool "Run commands with leading dash with controlling tty" +//config: default y +//config: depends on INIT +//config: help +//config: If this option is enabled, init will try to give a controlling +//config: tty to any command which has leading hyphen (often it's "-/bin/sh"). +//config: More precisely, init will do "ioctl(STDIN_FILENO, TIOCSCTTY, 0)". +//config: If device attached to STDIN_FILENO can be a ctty but is not yet +//config: a ctty for other session, it will become this process' ctty. +//config: This is not the traditional init behavour, but is often what you want +//config: in an embedded system where the console is only accessed during +//config: development or for maintenance. +//config: NB: using cttyhack applet may work better. +//config: +//config:config FEATURE_INIT_SYSLOG +//config: bool "Enable init to write to syslog" +//config: default y +//config: depends on INIT +//config: +//config:config FEATURE_EXTRA_QUIET +//config: bool "Be _extra_ quiet on boot" +//config: default y +//config: depends on INIT +//config: help +//config: Prevent init from logging some messages to the console during boot. +//config: +//config:config FEATURE_INIT_COREDUMPS +//config: bool "Support dumping core for child processes (debugging only)" +//config: default y +//config: depends on INIT +//config: help +//config: If this option is enabled and the file /.init_enable_core +//config: exists, then init will call setrlimit() to allow unlimited +//config: core file sizes. If this option is disabled, processes +//config: will not generate any core files. +//config: +//config:config FEATURE_INITRD +//config: bool "Support running init from within an initrd (not initramfs)" +//config: default y +//config: depends on INIT +//config: help +//config: Legacy support for running init under the old-style initrd. Allows +//config: the name linuxrc to act as init, and it doesn't assume init is PID 1. +//config: +//config: This does not apply to initramfs, which runs /init as PID 1 and +//config: requires no special support. +//config: +//config:config INIT_TERMINAL_TYPE +//config: string "Initial terminal type" +//config: default "linux" +//config: depends on INIT +//config: help +//config: This is the initial value set by init for the TERM environment +//config: variable. This variable is used by programs which make use of +//config: extended terminal capabilities. +//config: +//config: Note that on Linux, init attempts to detect serial terminal and +//config: sets TERM to "vt102" if one is found. + +//usage:#define init_trivial_usage +//usage: "" +//usage:#define init_full_usage "\n\n" +//usage: "Init is the parent of all processes" +//usage: +//usage:#define init_notes_usage +//usage: "This version of init is designed to be run only by the kernel.\n" +//usage: "\n" +//usage: "BusyBox init doesn't support multiple runlevels. The runlevels field of\n" +//usage: "the /etc/inittab file is completely ignored by BusyBox init. If you want\n" +//usage: "runlevels, use sysvinit.\n" +//usage: "\n" +//usage: "BusyBox init works just fine without an inittab. If no inittab is found,\n" +//usage: "it has the following default behavior:\n" +//usage: "\n" +//usage: " ::sysinit:/etc/init.d/rcS\n" +//usage: " ::askfirst:/bin/sh\n" +//usage: " ::ctrlaltdel:/sbin/reboot\n" +//usage: " ::shutdown:/sbin/swapoff -a\n" +//usage: " ::shutdown:/bin/umount -a -r\n" +//usage: " ::restart:/sbin/init\n" +//usage: "\n" +//usage: "if it detects that /dev/console is _not_ a serial console, it will also run:\n" +//usage: "\n" +//usage: " tty2::askfirst:/bin/sh\n" +//usage: " tty3::askfirst:/bin/sh\n" +//usage: " tty4::askfirst:/bin/sh\n" +//usage: "\n" +//usage: "If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n" +//usage: "\n" +//usage: " <id>:<runlevels>:<action>:<process>\n" +//usage: "\n" +//usage: " <id>:\n" +//usage: "\n" +//usage: " WARNING: This field has a non-traditional meaning for BusyBox init!\n" +//usage: " The id field is used by BusyBox init to specify the controlling tty for\n" +//usage: " the specified process to run on. The contents of this field are\n" +//usage: " appended to \"/dev/\" and used as-is. There is no need for this field to\n" +//usage: " be unique, although if it isn't you may have strange results. If this\n" +//usage: " field is left blank, the controlling tty is set to the console. Also\n" +//usage: " note that if BusyBox detects that a serial console is in use, then only\n" +//usage: " entries whose controlling tty is either the serial console or /dev/null\n" +//usage: " will be run. BusyBox init does nothing with utmp. We don't need no\n" +//usage: " stinkin' utmp.\n" +//usage: "\n" +//usage: " <runlevels>:\n" +//usage: "\n" +//usage: " The runlevels field is completely ignored.\n" +//usage: "\n" +//usage: " <action>:\n" +//usage: "\n" +//usage: " Valid actions include: sysinit, respawn, askfirst, wait,\n" +//usage: " once, restart, ctrlaltdel, and shutdown.\n" +//usage: "\n" +//usage: " The available actions can be classified into two groups: actions\n" +//usage: " that are run only once, and actions that are re-run when the specified\n" +//usage: " process exits.\n" +//usage: "\n" +//usage: " Run only-once actions:\n" +//usage: "\n" +//usage: " 'sysinit' is the first item run on boot. init waits until all\n" +//usage: " sysinit actions are completed before continuing. Following the\n" +//usage: " completion of all sysinit actions, all 'wait' actions are run.\n" +//usage: " 'wait' actions, like 'sysinit' actions, cause init to wait until\n" +//usage: " the specified task completes. 'once' actions are asynchronous,\n" +//usage: " therefore, init does not wait for them to complete. 'restart' is\n" +//usage: " the action taken to restart the init process. By default this should\n" +//usage: " simply run /sbin/init, but can be a script which runs pivot_root or it\n" +//usage: " can do all sorts of other interesting things. The 'ctrlaltdel' init\n" +//usage: " actions are run when the system detects that someone on the system\n" +//usage: " console has pressed the CTRL-ALT-DEL key combination. Typically one\n" +//usage: " wants to run 'reboot' at this point to cause the system to reboot.\n" +//usage: " Finally the 'shutdown' action specifies the actions to taken when\n" +//usage: " init is told to reboot. Unmounting filesystems and disabling swap\n" +//usage: " is a very good here.\n" +//usage: "\n" +//usage: " Run repeatedly actions:\n" +//usage: "\n" +//usage: " 'respawn' actions are run after the 'once' actions. When a process\n" +//usage: " started with a 'respawn' action exits, init automatically restarts\n" +//usage: " it. Unlike sysvinit, BusyBox init does not stop processes from\n" +//usage: " respawning out of control. The 'askfirst' actions acts just like\n" +//usage: " respawn, except that before running the specified process it\n" +//usage: " displays the line \"Please press Enter to activate this console.\"\n" +//usage: " and then waits for the user to press enter before starting the\n" +//usage: " specified process.\n" +//usage: "\n" +//usage: " Unrecognized actions (like initdefault) will cause init to emit an\n" +//usage: " error message, and then go along with its business. All actions are\n" +//usage: " run in the order they appear in /etc/inittab.\n" +//usage: "\n" +//usage: " <process>:\n" +//usage: "\n" +//usage: " Specifies the process to be executed and its command line.\n" +//usage: "\n" +//usage: "Example /etc/inittab file:\n" +//usage: "\n" +//usage: " # This is run first except when booting in single-user mode\n" +//usage: " #\n" +//usage: " ::sysinit:/etc/init.d/rcS\n" +//usage: " \n" +//usage: " # /bin/sh invocations on selected ttys\n" +//usage: " #\n" +//usage: " # Start an \"askfirst\" shell on the console (whatever that may be)\n" +//usage: " ::askfirst:-/bin/sh\n" +//usage: " # Start an \"askfirst\" shell on /dev/tty2-4\n" +//usage: " tty2::askfirst:-/bin/sh\n" +//usage: " tty3::askfirst:-/bin/sh\n" +//usage: " tty4::askfirst:-/bin/sh\n" +//usage: " \n" +//usage: " # /sbin/getty invocations for selected ttys\n" +//usage: " #\n" +//usage: " tty4::respawn:/sbin/getty 38400 tty4\n" +//usage: " tty5::respawn:/sbin/getty 38400 tty5\n" +//usage: " \n" +//usage: " \n" +//usage: " # Example of how to put a getty on a serial line (for a terminal)\n" +//usage: " #\n" +//usage: " #::respawn:/sbin/getty -L ttyS0 9600 vt100\n" +//usage: " #::respawn:/sbin/getty -L ttyS1 9600 vt100\n" +//usage: " #\n" +//usage: " # Example how to put a getty on a modem line\n" +//usage: " #::respawn:/sbin/getty 57600 ttyS2\n" +//usage: " \n" +//usage: " # Stuff to do when restarting the init process\n" +//usage: " ::restart:/sbin/init\n" +//usage: " \n" +//usage: " # Stuff to do before rebooting\n" +//usage: " ::ctrlaltdel:/sbin/reboot\n" +//usage: " ::shutdown:/bin/umount -a -r\n" +//usage: " ::shutdown:/sbin/swapoff -a\n" + #include "libbb.h" #include <syslog.h> #include <paths.h> |