* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Adjusted by so many folks, it's impossible to keep track.
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * 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.
+
#include "libbb.h"
+#include <syslog.h>
#include <paths.h>
-#include <sys/reboot.h>
-#include <sys/syslog.h>
+#include <sys/resource.h>
+#ifdef __linux__
+#include <linux/vt.h>
+#endif
+#include "reboot.h" /* reboot() constants */
+
+/* Used only for sanitizing purposes in set_sane_term() below. On systems where
+ * the baud rate is stored in a separate field, we can safely disable them. */
+#ifndef CBAUD
+# define CBAUD 0
+# define CBAUDEX 0
+#endif
+
+/* Was a CONFIG_xxx option. A lot of people were building
+ * not fully functional init by switching it on! */
+#define DEBUG_INIT 0
-#define INIT_BUFFS_SIZE 256
+#define COMMAND_SIZE 256
#define CONSOLE_NAME_SIZE 32
-#define MAXENV 16 /* Number of env. vars */
+/* Default sysinit script. */
+#ifndef INIT_SCRIPT
+#define INIT_SCRIPT "/etc/init.d/rcS"
+#endif
+
+/* Each type of actions can appear many times. They will be
+ * handled in order. RESTART is an exception, only 1st is used.
+ */
+/* Start these actions first and wait for completion */
+#define SYSINIT 0x01
+/* Start these after SYSINIT and wait for completion */
+#define WAIT 0x02
+/* Start these after WAIT and *dont* wait for completion */
+#define ONCE 0x04
/*
- * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
- * before processes are spawned to set core file size as unlimited.
- * This is for debugging only. Don't use this is production, unless
- * you want core dumps lying about....
+ * NB: while SYSINIT/WAIT/ONCE are being processed,
+ * SIGHUP ("reread /etc/inittab") will be processed only after
+ * each group of actions. If new inittab adds, say, a SYSINIT action,
+ * it will not be run, since init is already "past SYSINIT stage".
*/
-#define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
-#include <sys/resource.h>
+/* Start these after ONCE are started, restart on exit */
+#define RESPAWN 0x08
+/* Like RESPAWN, but wait for <Enter> to be pressed on tty */
+#define ASKFIRST 0x10
+/*
+ * Start these on SIGINT, and wait for completion.
+ * Then go back to respawning RESPAWN and ASKFIRST actions.
+ * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
+ */
+#define CTRLALTDEL 0x20
+/*
+ * Start these before killing all processes in preparation for
+ * running RESTART actions or doing low-level halt/reboot/poweroff
+ * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
+ * Wait for completion before proceeding.
+ */
+#define SHUTDOWN 0x40
+/*
+ * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
+ * then all processes are killed, then init exec's 1st RESTART action,
+ * replacing itself by it. If no RESTART action specified,
+ * SIGQUIT has no effect.
+ */
+#define RESTART 0x80
-#define INITTAB "/etc/inittab" /* inittab file location */
-#ifndef INIT_SCRIPT
-#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
-#endif
-/* Allowed init action types */
-#define SYSINIT 0x001
-#define RESPAWN 0x002
-#define ASKFIRST 0x004
-#define WAIT 0x008
-#define ONCE 0x010
-#define CTRLALTDEL 0x020
-#define SHUTDOWN 0x040
-#define RESTART 0x080
-
-#define STR_SYSINIT "\x01"
-#define STR_RESPAWN "\x02"
-#define STR_ASKFIRST "\x04"
-#define STR_WAIT "\x08"
-#define STR_ONCE "\x10"
-#define STR_CTRLALTDEL "\x20"
-#define STR_SHUTDOWN "\x40"
-#define STR_RESTART "\x80"
-
-/* Set up a linked list of init_actions, to be read from inittab */
+/* A linked list of init_actions, to be read from inittab */
struct init_action {
struct init_action *next;
pid_t pid;
- uint8_t action;
+ uint8_t action_type;
char terminal[CONSOLE_NAME_SIZE];
- char command[INIT_BUFFS_SIZE];
+ char command[COMMAND_SIZE];
};
-/* Static variables */
static struct init_action *init_action_list = NULL;
static const char *log_console = VC_5;
-static sig_atomic_t got_cont = 0;
enum {
L_LOG = 0x1,
L_CONSOLE = 0x2,
-
-#if ENABLE_FEATURE_EXTRA_QUIET
- MAYBE_CONSOLE = 0x0,
-#else
- MAYBE_CONSOLE = L_CONSOLE,
-#endif
-
-#ifndef RB_HALT_SYSTEM
- RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
- RB_ENABLE_CAD = 0x89abcdef,
- RB_DISABLE_CAD = 0,
- RB_POWER_OFF = 0x4321fedc,
- RB_AUTOBOOT = 0x01234567,
-#endif
-};
-
-static const char *const environment[] = {
- "HOME=/",
- bb_PATH_root_path,
- "SHELL=/bin/sh",
- "USER=root",
- NULL
};
-/* Function prototypes */
-static void delete_init_action(struct init_action *a);
-static int waitfor(pid_t pid);
-static void shutdown_signal(int sig);
-
-static void loop_forever(void)
-{
- while (1)
- sleep(1);
-}
-
/* Print a message to the specified device.
- * Device may be bitwise-or'd from L_LOG | L_CONSOLE */
-#define messageD(...) do { if (ENABLE_DEBUG_INIT) message(__VA_ARGS__); } while (0)
-static void message(int device, const char *fmt, ...)
+ * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
+ * NB: careful, we can be called after vfork!
+ */
+#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
+static void message(int where, const char *fmt, ...)
__attribute__ ((format(printf, 2, 3)));
-static void message(int device, const char *fmt, ...)
+static void message(int where, const char *fmt, ...)
{
- static int log_fd = -1;
va_list arguments;
- int l;
+ unsigned l;
char msg[128];
msg[0] = '\r';
va_start(arguments, fmt);
- vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
+ l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
+ if (l > sizeof(msg) - 1)
+ l = sizeof(msg) - 1;
va_end(arguments);
- msg[sizeof(msg) - 2] = '\0';
- l = strlen(msg);
- if (ENABLE_FEATURE_INIT_SYSLOG) {
+#if ENABLE_FEATURE_INIT_SYSLOG
+ msg[l] = '\0';
+ if (where & L_LOG) {
/* Log the message to syslogd */
- if (device & L_LOG) {
- /* don't out "\r" */
- openlog(applet_name, 0, LOG_DAEMON);
- syslog(LOG_INFO, "init: %s", msg + 1);
- closelog();
- }
- msg[l++] = '\n';
- msg[l] = '\0';
- } else {
+ openlog(applet_name, 0, LOG_DAEMON);
+ /* don't print "\r" */
+ syslog(LOG_INFO, "%s", msg + 1);
+ closelog();
+ }
+ msg[l++] = '\n';
+ msg[l] = '\0';
+#else
+ {
+ static int log_fd = -1;
+
msg[l++] = '\n';
msg[l] = '\0';
/* Take full control of the log tty, and never close it.
* It's mine, all mine! Muhahahaha! */
if (log_fd < 0) {
if (!log_console) {
- log_fd = 2;
+ log_fd = STDERR_FILENO;
} else {
log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
if (log_fd < 0) {
bb_error_msg("can't log to %s", log_console);
- device = L_CONSOLE;
+ where = L_CONSOLE;
} else {
close_on_exec_on(log_fd);
}
}
}
- if (device & L_LOG) {
+ if (where & L_LOG) {
full_write(log_fd, msg, l);
- if (log_fd == 2)
+ if (log_fd == STDERR_FILENO)
return; /* don't print dup messages */
}
}
+#endif
- if (device & L_CONSOLE) {
+ if (where & L_CONSOLE) {
/* Send console messages to console so people will see them. */
- full_write(2, msg, l);
+ full_write(STDERR_FILENO, msg, l);
}
}
-/* From <linux/serial.h> */
-struct serial_struct {
- int type;
- int line;
- unsigned int port;
- int irq;
- int flags;
- int xmit_fifo_size;
- int custom_divisor;
- int baud_base;
- unsigned short close_delay;
- char io_type;
- char reserved_char[1];
- int hub6;
- unsigned short closing_wait; /* time to wait before closing */
- unsigned short closing_wait2; /* no longer used... */
- unsigned char *iomem_base;
- unsigned short iomem_reg_shift;
- unsigned int port_high;
- unsigned long iomap_base; /* cookie passed into ioremap */
- int reserved[1];
- /* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
- uint32_t bbox_reserved[16];
-};
static void console_init(void)
{
- struct serial_struct sr;
+#ifdef VT_OPENQRY
+ int vtno;
+#endif
char *s;
s = getenv("CONSOLE");
- if (!s) s = getenv("console");
+ if (!s)
+ s = getenv("console");
if (s) {
int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
if (fd >= 0) {
- dup2(fd, 0);
- dup2(fd, 1);
- dup2(fd, 2);
- while (fd > 2) close(fd--);
+ dup2(fd, STDIN_FILENO);
+ dup2(fd, STDOUT_FILENO);
+ xmove_fd(fd, STDERR_FILENO);
}
- messageD(L_LOG, "console='%s'", s);
+ dbg_message(L_LOG, "console='%s'", s);
} else {
- /* Make sure fd 0,1,2 are not closed */
+ /* Make sure fd 0,1,2 are not closed
+ * (so that they won't be used by future opens) */
bb_sanitize_stdio();
+// Users report problems
+// /* Make sure init can't be blocked by writing to stderr */
+// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
}
s = getenv("TERM");
- if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
- /* Force the TERM setting to vt102 for serial console
+#ifdef VT_OPENQRY
+ if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
+ /* Not a linux terminal, probably serial console.
+ * Force the TERM setting to vt102
* if TERM is set to linux (the default) */
if (!s || strcmp(s, "linux") == 0)
putenv((char*)"TERM=vt102");
if (!ENABLE_FEATURE_INIT_SYSLOG)
log_console = NULL;
- } else if (!s)
- putenv((char*)"TERM=linux");
+ } else
+#endif
+ if (!s)
+ putenv((char*)"TERM=" CONFIG_INIT_TERMINAL_TYPE);
}
-/* Set terminal settings to reasonable defaults */
+/* Set terminal settings to reasonable defaults.
+ * NB: careful, we can be called after vfork! */
static void set_sane_term(void)
{
struct termios tty;
tty.c_cc[VSTOP] = 19; /* C-s */
tty.c_cc[VSUSP] = 26; /* C-z */
- /* use line dicipline 0 */
+#ifdef __linux__
+ /* use line discipline 0 */
tty.c_line = 0;
+#endif
/* Make it be sane */
- tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
+#ifndef CRTSCTS
+# define CRTSCTS 0
+#endif
+ /* added CRTSCTS to fix Debian bug 528560 */
+ tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD | CRTSCTS;
tty.c_cflag |= CREAD | HUPCL | CLOCAL;
/* input modes */
tty.c_oflag = OPOST | ONLCR;
/* local modes */
- tty.c_lflag =
- ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
+ tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
- tcsetattr(STDIN_FILENO, TCSANOW, &tty);
+ tcsetattr_stdin_TCSANOW(&tty);
}
-/* Open the new terminal device */
-static void open_stdio_to_tty(const char* tty_name, int fail)
+/* Open the new terminal device.
+ * NB: careful, we can be called after vfork! */
+static int open_stdio_to_tty(const char* tty_name)
{
/* empty tty_name means "use init's tty", else... */
if (tty_name[0]) {
- int fd = device_open(tty_name, O_RDWR);
- if (fd < 0) {
- message(L_LOG | L_CONSOLE, "Can't open %s: %s",
+ int fd;
+
+ close(STDIN_FILENO);
+ /* fd can be only < 0 or 0: */
+ fd = device_open(tty_name, O_RDWR);
+ if (fd) {
+ message(L_LOG | L_CONSOLE, "can't open %s: %s",
tty_name, strerror(errno));
- if (fail)
- _exit(1);
- if (!ENABLE_DEBUG_INIT)
- shutdown_signal(SIGUSR1);
- else
- _exit(2);
- } else {
- dup2(fd, 0);
- dup2(fd, 1);
- dup2(fd, 2);
- if (fd > 2) close(fd);
+ return 0; /* failure */
}
+ dup2(STDIN_FILENO, STDOUT_FILENO);
+ dup2(STDIN_FILENO, STDERR_FILENO);
}
set_sane_term();
+ return 1; /* success */
}
-/* Used only by run_actions */
-static pid_t run(const struct init_action *a)
+static void reset_sighandlers_and_unblock_sigs(void)
{
- int i;
- pid_t pid;
- char *s, *tmpCmd, *cmdpath;
- char *cmd[INIT_BUFFS_SIZE];
- char buf[INIT_BUFFS_SIZE + 6]; /* INIT_BUFFS_SIZE+strlen("exec ")+1 */
- sigset_t nmask, omask;
-
- /* Block sigchild while forking (why?) */
- sigemptyset(&nmask);
- sigaddset(&nmask, SIGCHLD);
- sigprocmask(SIG_BLOCK, &nmask, &omask);
- pid = fork();
- sigprocmask(SIG_SETMASK, &omask, NULL);
-
- if (pid < 0)
- message(L_LOG | L_CONSOLE, "Can't fork");
- if (pid)
- return pid;
-
- /* Child */
-
- /* Reset signal handlers that were set by the parent process */
- signal(SIGUSR1, SIG_DFL);
- signal(SIGUSR2, SIG_DFL);
- signal(SIGINT, SIG_DFL);
- signal(SIGTERM, SIG_DFL);
- signal(SIGHUP, SIG_DFL);
- signal(SIGQUIT, SIG_DFL);
- signal(SIGCONT, SIG_DFL);
- signal(SIGSTOP, SIG_DFL);
- signal(SIGTSTP, SIG_DFL);
-
- /* Create a new session and make ourself the process
- * group leader */
- setsid();
-
- /* Open the new terminal device */
- open_stdio_to_tty(a->terminal, 1 /* - exit if open fails*/);
-
-#ifdef BUT_RUN_ACTIONS_ALREADY_DOES_WAITING
-# define BRAADS 1
-#else
-# define BRAADS 0
-#endif
- /* If the init Action requires us to wait, then force the
- * supplied terminal to be the controlling tty. */
- if (BRAADS && a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
-
- /* Now fork off another process to just hang around */
- pid = fork();
- if (pid < 0) {
- message(L_LOG | L_CONSOLE, "Can't fork");
- _exit(1);
- }
+ bb_signals(0
+ + (1 << SIGUSR1)
+ + (1 << SIGUSR2)
+ + (1 << SIGTERM)
+ + (1 << SIGQUIT)
+ + (1 << SIGINT)
+ + (1 << SIGHUP)
+ + (1 << SIGTSTP)
+ + (1 << SIGSTOP)
+ , SIG_DFL);
+ sigprocmask_allsigs(SIG_UNBLOCK);
+}
- if (pid > 0) {
- /* Parent - wait till the child is done */
- signal(SIGINT, SIG_IGN);
- signal(SIGTSTP, SIG_IGN);
- signal(SIGQUIT, SIG_IGN);
- signal(SIGCHLD, SIG_DFL);
-
- waitfor(pid);
- /* See if stealing the controlling tty back is necessary */
- if (tcgetpgrp(0) != getpid())
- _exit(0);
-
- /* Use a temporary process to steal the controlling tty. */
- pid = fork();
- if (pid < 0) {
- message(L_LOG | L_CONSOLE, "Can't fork");
- _exit(1);
- }
- if (pid == 0) {
- setsid();
- ioctl(0, TIOCSCTTY, 1);
- _exit(0);
- }
- waitfor(pid);
- _exit(0);
- }
+/* Wrapper around exec:
+ * Takes string (max COMMAND_SIZE chars).
+ * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
+ * Otherwise splits words on whitespace, deals with leading dash,
+ * and uses plain exec().
+ * NB: careful, we can be called after vfork!
+ */
+static void init_exec(const char *command)
+{
+ char *cmd[COMMAND_SIZE / 2];
+ char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
+ int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
- /* Child - fall though to actually execute things */
- }
+ command += dash;
/* See if any special /bin/sh requiring characters are present */
- if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
- cmd[0] = (char*)DEFAULT_SHELL;
+ if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
+ sprintf(buf, "exec %s", command); /* excluding "-" */
+ /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
+ cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
cmd[1] = (char*)"-c";
- cmd[2] = strcat(strcpy(buf, "exec "), a->command);
+ cmd[2] = buf;
cmd[3] = NULL;
+ command = LIBBB_DEFAULT_LOGIN_SHELL + 1;
} else {
/* Convert command (char*) into cmd (char**, one word per string) */
- strcpy(buf, a->command);
- s = buf;
- for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
- if (*tmpCmd != '\0') {
- cmd[i] = tmpCmd;
+ char *word, *next;
+ int i = 0;
+ next = strcpy(buf, command - dash); /* command including "-" */
+ while ((word = strsep(&next, " \t")) != NULL) {
+ if (*word != '\0') { /* not two spaces/tabs together? */
+ cmd[i] = word;
i++;
}
}
cmd[i] = NULL;
}
-
- cmdpath = cmd[0];
-
- /*
- * Interactive shells want to see a dash in argv[0]. This
- * typically is handled by login, argv will be setup this
- * way if a dash appears at the front of the command path
- * (like "-/bin/sh").
+ /* If we saw leading "-", it is interactive shell.
+ * Try harder to give it a controlling tty.
*/
- if (*cmdpath == '-') {
- /* skip over the dash */
- ++cmdpath;
+ if (ENABLE_FEATURE_INIT_SCTTY && dash) {
+ /* _Attempt_ to make stdin a controlling tty. */
+ ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
+ }
+ /* Here command never contains the dash, cmd[0] might */
+ BB_EXECVP(command, cmd);
+ message(L_LOG | L_CONSOLE, "can't run '%s': %s", command, strerror(errno));
+ /* returns if execvp fails */
+}
-#ifdef WHY_WE_DO_THIS_SHELL_MUST_HANDLE_THIS_ITSELF
-# define WWDTSMHTI 1
-#else
-# define WWDTSMHTI 0
-#endif
- if (WWDTSMHTI) {
- /* find the last component in the command pathname */
- s = bb_get_last_path_component_nostrip(cmdpath);
- /* make a new argv[0] */
- cmd[0] = malloc(strlen(s) + 2);
- if (cmd[0] == NULL) {
- message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted);
- cmd[0] = cmdpath;
- } else {
- cmd[0][0] = '-';
- strcpy(cmd[0] + 1, s);
- }
- }
+/* Used only by run_actions */
+static pid_t run(const struct init_action *a)
+{
+ pid_t pid;
- /* Establish this process as session leader and
- * _attempt_ to make stdin a controlling tty.
- */
- if (ENABLE_FEATURE_INIT_SCTTY)
- ioctl(0, TIOCSCTTY, 0 /*only try, don't steal*/);
+ /* Careful: don't be affected by a signal in vforked child */
+ sigprocmask_allsigs(SIG_BLOCK);
+ if (BB_MMU && (a->action_type & ASKFIRST))
+ pid = fork();
+ else
+ pid = vfork();
+ if (pid < 0)
+ message(L_LOG | L_CONSOLE, "can't fork");
+ if (pid) {
+ sigprocmask_allsigs(SIG_UNBLOCK);
+ return pid; /* Parent or error */
}
- if (a->action & ASKFIRST) {
+ /* Child */
+
+ /* Reset signal handlers that were set by the parent process */
+ reset_sighandlers_and_unblock_sigs();
+
+ /* Create a new session and make ourself the process group leader */
+ setsid();
+
+ /* Open the new terminal device */
+ if (!open_stdio_to_tty(a->terminal))
+ _exit(EXIT_FAILURE);
+
+ /* NB: on NOMMU we can't wait for input in child, so
+ * "askfirst" will work the same as "respawn". */
+ if (BB_MMU && (a->action_type & ASKFIRST)) {
static const char press_enter[] ALIGN1 =
#ifdef CUSTOMIZED_BANNER
#include CUSTOMIZED_BANNER
* be allowed to start a shell or whatever an init script
* specifies.
*/
- messageD(L_LOG, "waiting for enter to start '%s'"
+ dbg_message(L_LOG, "waiting for enter to start '%s'"
"(pid %d, tty '%s')\n",
- cmdpath, getpid(), a->terminal);
- full_write(1, press_enter, sizeof(press_enter) - 1);
- while (safe_read(0, &c, 1) == 1 && c != '\n')
+ a->command, getpid(), a->terminal);
+ full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
+ while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
continue;
}
- /* Log the process name and args */
- message(L_LOG, "starting pid %d, tty '%s': '%s'",
- getpid(), a->terminal, cmdpath);
-
+ /*
+ * When a file named /.init_enable_core exists, setrlimit is called
+ * before processes are spawned to set core file size as unlimited.
+ * This is for debugging only. Don't use this is production, unless
+ * you want core dumps lying about....
+ */
if (ENABLE_FEATURE_INIT_COREDUMPS) {
- struct stat sb;
- if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
+ if (access("/.init_enable_core", F_OK) == 0) {
struct rlimit limit;
-
limit.rlim_cur = RLIM_INFINITY;
limit.rlim_max = RLIM_INFINITY;
setrlimit(RLIMIT_CORE, &limit);
}
}
+ /* Log the process name and args */
+ message(L_LOG, "starting pid %d, tty '%s': '%s'",
+ getpid(), a->terminal, a->command);
+
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
- BB_EXECVP(cmdpath, cmd);
-
+ init_exec(a->command);
/* We're still here? Some error happened. */
- message(L_LOG | L_CONSOLE, "Cannot run '%s': %s",
- cmdpath, strerror(errno));
_exit(-1);
}
-static int waitfor(pid_t runpid)
+static struct init_action *mark_terminated(pid_t pid)
+{
+ struct init_action *a;
+
+ if (pid > 0) {
+ for (a = init_action_list; a; a = a->next) {
+ if (a->pid == pid) {
+ a->pid = 0;
+ return a;
+ }
+ }
+ update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL,
+ /*username:*/ NULL,
+ /*hostname:*/ NULL);
+ }
+ return NULL;
+}
+
+static void waitfor(pid_t pid)
{
- int status, wpid;
+ /* waitfor(run(x)): protect against failed fork inside run() */
+ if (pid <= 0)
+ return;
+ /* Wait for any child (prevent zombies from exiting orphaned processes)
+ * but exit the loop only when specified one has exited. */
while (1) {
- wpid = waitpid(runpid, &status, 0);
- if (wpid == -1 && errno == EINTR)
- continue;
- break;
+ pid_t wpid = wait(NULL);
+ mark_terminated(wpid);
+ /* Unsafe. SIGTSTP handler might have wait'ed it already */
+ /*if (wpid == pid) break;*/
+ /* More reliable: */
+ if (kill(pid, 0))
+ break;
}
- return wpid;
}
/* Run all commands of a particular type */
-static void run_actions(int action)
+static void run_actions(int action_type)
{
- struct init_action *a, *tmp;
-
- for (a = init_action_list; a; a = tmp) {
- tmp = a->next;
- if (a->action == action) {
- // Pointless: run() will error out if open of device fails.
- ///* a->terminal of "" means "init's console" */
- //if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
- // //message(L_LOG | L_CONSOLE, "Device %s cannot be opened in RW mode", a->terminal /*, strerror(errno)*/);
- // delete_init_action(a);
- //} else
- if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
- waitfor(run(a));
- delete_init_action(a);
- } else if (a->action & ONCE) {
- run(a);
- delete_init_action(a);
- } else if (a->action & (RESPAWN | ASKFIRST)) {
- /* Only run stuff with pid==0. If they have
- * a pid, that means it is still running */
- if (a->pid == 0) {
- a->pid = run(a);
- }
- }
+ struct init_action *a;
+
+ for (a = init_action_list; a; a = a->next) {
+ if (!(a->action_type & action_type))
+ continue;
+
+ if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
+ pid_t pid = run(a);
+ if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
+ waitfor(pid);
+ }
+ if (a->action_type & (RESPAWN | ASKFIRST)) {
+ /* Only run stuff with pid == 0. If pid != 0,
+ * it is already running
+ */
+ if (a->pid == 0)
+ a->pid = run(a);
+ }
+ }
+}
+
+static void new_init_action(uint8_t action_type, const char *command, const char *cons)
+{
+ struct init_action *a, **nextp;
+
+ /* Scenario:
+ * old inittab:
+ * ::shutdown:umount -a -r
+ * ::shutdown:swapoff -a
+ * new inittab:
+ * ::shutdown:swapoff -a
+ * ::shutdown:umount -a -r
+ * On reload, we must ensure entries end up in correct order.
+ * To achieve that, if we find a matching entry, we move it
+ * to the end.
+ */
+ nextp = &init_action_list;
+ while ((a = *nextp) != NULL) {
+ /* Don't enter action if it's already in the list,
+ * This prevents losing running RESPAWNs.
+ */
+ if (strcmp(a->command, command) == 0
+ && strcmp(a->terminal, cons) == 0
+ ) {
+ /* Remove from list */
+ *nextp = a->next;
+ /* Find the end of the list */
+ while (*nextp != NULL)
+ nextp = &(*nextp)->next;
+ a->next = NULL;
+ break;
+ }
+ nextp = &a->next;
+ }
+
+ if (!a)
+ a = xzalloc(sizeof(*a));
+ /* Append to the end of the list */
+ *nextp = a;
+ a->action_type = action_type;
+ safe_strncpy(a->command, command, sizeof(a->command));
+ safe_strncpy(a->terminal, cons, sizeof(a->terminal));
+ dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
+ a->command, a->action_type, a->terminal);
+}
+
+/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
+ * then parse_inittab() simply adds in some default
+ * actions(i.e., runs INIT_SCRIPT and then starts a pair
+ * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
+ * _is_ defined, but /etc/inittab is missing, this
+ * results in the same set of default behaviors.
+ */
+static void parse_inittab(void)
+{
+#if ENABLE_FEATURE_USE_INITTAB
+ char *token[4];
+ parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
+
+ if (parser == NULL)
+#endif
+ {
+ /* No inittab file - set up some default behavior */
+ /* Reboot on Ctrl-Alt-Del */
+ new_init_action(CTRLALTDEL, "reboot", "");
+ /* Umount all filesystems on halt/reboot */
+ new_init_action(SHUTDOWN, "umount -a -r", "");
+ /* Swapoff on halt/reboot */
+ if (ENABLE_SWAPONOFF)
+ new_init_action(SHUTDOWN, "swapoff -a", "");
+ /* Prepare to restart init when a QUIT is received */
+ new_init_action(RESTART, "init", "");
+ /* Askfirst shell on tty1-4 */
+ new_init_action(ASKFIRST, bb_default_login_shell, "");
+//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
+ new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
+ new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
+ new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
+ /* sysinit */
+ new_init_action(SYSINIT, INIT_SCRIPT, "");
+ return;
+ }
+
+#if ENABLE_FEATURE_USE_INITTAB
+ /* optional_tty:ignored_runlevel:action:command
+ * Delims are not to be collapsed and need exactly 4 tokens
+ */
+ while (config_read(parser, token, 4, 0, "#:",
+ PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
+ /* order must correspond to SYSINIT..RESTART constants */
+ static const char actions[] ALIGN1 =
+ "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
+ "ctrlaltdel\0""shutdown\0""restart\0";
+ int action;
+ char *tty = token[0];
+
+ if (!token[3]) /* less than 4 tokens */
+ goto bad_entry;
+ action = index_in_strings(actions, token[2]);
+ if (action < 0 || !token[3][0]) /* token[3]: command */
+ goto bad_entry;
+ /* turn .*TTY -> /dev/TTY */
+ if (tty[0]) {
+ tty = concat_path_file("/dev/", skip_dev_pfx(tty));
}
+ new_init_action(1 << action, token[3], tty);
+ if (tty[0])
+ free(tty);
+ continue;
+ bad_entry:
+ message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
+ parser->lineno);
}
+ config_close(parser);
+#endif
}
-static void init_reboot(unsigned long magic)
+static void pause_and_low_level_reboot(unsigned magic) NORETURN;
+static void pause_and_low_level_reboot(unsigned magic)
{
pid_t pid;
- /* We have to fork here, since the kernel calls do_exit(0) in
- * linux/kernel/sys.c, which can cause the machine to panic when
- * the init process is killed.... */
+
+ /* Allow time for last message to reach serial console, etc */
+ sleep(1);
+
+ /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
+ * in linux/kernel/sys.c, which can cause the machine to panic when
+ * the init process exits... */
pid = vfork();
if (pid == 0) { /* child */
reboot(magic);
- _exit(0);
+ _exit(EXIT_SUCCESS);
}
- waitpid(pid, NULL, 0);
+ while (1)
+ sleep(1);
}
-static void shutdown_system(void)
+static void run_shutdown_and_kill_processes(void)
{
- sigset_t block_signals;
-
- /* run everything to be run at "shutdown". This is done _prior_
+ /* Run everything to be run at "shutdown". This is done _prior_
* to killing everything, in case people wish to use scripts to
* shut things down gracefully... */
run_actions(SHUTDOWN);
- /* first disable all our signals */
- sigemptyset(&block_signals);
- sigaddset(&block_signals, SIGHUP);
- sigaddset(&block_signals, SIGQUIT);
- sigaddset(&block_signals, SIGCHLD);
- sigaddset(&block_signals, SIGUSR1);
- sigaddset(&block_signals, SIGUSR2);
- sigaddset(&block_signals, SIGINT);
- sigaddset(&block_signals, SIGTERM);
- sigaddset(&block_signals, SIGCONT);
- sigaddset(&block_signals, SIGSTOP);
- sigaddset(&block_signals, SIGTSTP);
- sigprocmask(SIG_BLOCK, &block_signals, NULL);
-
message(L_CONSOLE | L_LOG, "The system is going down NOW!");
- /* Allow Ctrl-Alt-Del to reboot system. */
- init_reboot(RB_ENABLE_CAD);
-
/* Send signals to every process _except_ pid 1 */
- message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
kill(-1, SIGTERM);
+ message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
sync();
sleep(1);
- message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL");
kill(-1, SIGKILL);
+ message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
sync();
- sleep(1);
+ /*sleep(1); - callers take care about making a pause */
}
-static void shutdown_signal(int sig)
+/* Signal handling by init:
+ *
+ * For process with PID==1, on entry kernel sets all signals to SIG_DFL
+ * and unmasks all signals. However, for process with PID==1,
+ * default action (SIG_DFL) on any signal is to ignore it,
+ * even for special signals SIGKILL and SIGCONT.
+ * Also, any signal can be caught or blocked.
+ * (but SIGSTOP is still handled specially, at least in 2.6.20)
+ *
+ * We install two kinds of handlers, "immediate" and "delayed".
+ *
+ * Immediate handlers execute at any time, even while, say, sysinit
+ * is running.
+ *
+ * Delayed handlers just set a flag variable. The variable is checked
+ * in the main loop and acted upon.
+ *
+ * halt/poweroff/reboot and restart have immediate handlers.
+ * They only traverse linked list of struct action's, never modify it,
+ * this should be safe to do even in signal handler. Also they
+ * never return.
+ *
+ * SIGSTOP and SIGTSTP have immediate handlers. They just wait
+ * for SIGCONT to happen.
+ *
+ * SIGHUP has a delayed handler, because modifying linked list
+ * of struct action's from a signal handler while it is manipulated
+ * by the program may be disastrous.
+ *
+ * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
+ * it to happen even somewhere inside "sysinit" would be a bit awkward.
+ *
+ * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
+ * and only one will be remembered and acted upon.
+ */
+
+/* The SIGUSR[12]/SIGTERM handler */
+static void halt_reboot_pwoff(int sig) NORETURN;
+static void halt_reboot_pwoff(int sig)
{
const char *m;
- int rb;
+ unsigned rb;
- shutdown_system();
+ /* We may call run() and it unmasks signals,
+ * including the one masked inside this signal handler.
+ * Testcase which would start multiple reboot scripts:
+ * while true; do reboot; done
+ * Preventing it:
+ */
+ reset_sighandlers_and_unblock_sigs();
+
+ run_shutdown_and_kill_processes();
m = "halt";
rb = RB_HALT_SYSTEM;
m = "poweroff";
rb = RB_POWER_OFF;
}
- message(L_CONSOLE | L_LOG, "Requesting system %s", m);
- /* allow time for last message to reach serial console */
- sleep(2);
- init_reboot(rb);
- loop_forever();
-}
-
-static void exec_signal(int sig ATTRIBUTE_UNUSED)
-{
- struct init_action *a, *tmp;
- sigset_t unblock_signals;
-
- for (a = init_action_list; a; a = tmp) {
- tmp = a->next;
- if (a->action & RESTART) {
- shutdown_system();
-
- /* unblock all signals, blocked in shutdown_system() */
- sigemptyset(&unblock_signals);
- sigaddset(&unblock_signals, SIGHUP);
- sigaddset(&unblock_signals, SIGQUIT);
- sigaddset(&unblock_signals, SIGCHLD);
- sigaddset(&unblock_signals, SIGUSR1);
- sigaddset(&unblock_signals, SIGUSR2);
- sigaddset(&unblock_signals, SIGINT);
- sigaddset(&unblock_signals, SIGTERM);
- sigaddset(&unblock_signals, SIGCONT);
- sigaddset(&unblock_signals, SIGSTOP);
- sigaddset(&unblock_signals, SIGTSTP);
- sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
-
- /* Open the new terminal device */
- open_stdio_to_tty(a->terminal, 0 /* - shutdown_signal(SIGUSR1) [halt] if open fails */);
-
- messageD(L_CONSOLE | L_LOG, "Trying to re-exec %s", a->command);
- BB_EXECLP(a->command, a->command, NULL);
-
- message(L_CONSOLE | L_LOG, "Cannot run '%s': %s",
- a->command, strerror(errno));
- sleep(2);
- init_reboot(RB_HALT_SYSTEM);
- loop_forever();
- }
- }
+ message(L_CONSOLE, "Requesting system %s", m);
+ pause_and_low_level_reboot(rb);
+ /* not reached */
}
-static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
+/* Handler for QUIT - exec "restart" action,
+ * else (no such action defined) do nothing */
+static void restart_handler(int sig UNUSED_PARAM)
{
- run_actions(CTRLALTDEL);
-}
-
-/* The SIGSTOP & SIGTSTP handler */
-static void stop_handler(int sig ATTRIBUTE_UNUSED)
-{
- int saved_errno = errno;
-
- got_cont = 0;
- while (!got_cont)
- pause();
+ struct init_action *a;
- errno = saved_errno;
-}
+ for (a = init_action_list; a; a = a->next) {
+ if (!(a->action_type & RESTART))
+ continue;
-/* The SIGCONT handler */
-static void cont_handler(int sig ATTRIBUTE_UNUSED)
-{
- got_cont = 1;
-}
+ /* Starting from here, we won't return.
+ * Thus don't need to worry about preserving errno
+ * and such.
+ */
-static void new_init_action(uint8_t action, const char *command, const char *cons)
-{
- struct init_action *new_action, *a, *last;
+ reset_sighandlers_and_unblock_sigs();
- if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
- return;
+ run_shutdown_and_kill_processes();
- /* Append to the end of the list */
- for (a = last = init_action_list; a; a = a->next) {
- /* don't enter action if it's already in the list,
- * but do overwrite existing actions */
- if ((strcmp(a->command, command) == 0)
- && (strcmp(a->terminal, cons) == 0)
- ) {
- a->action = action;
- return;
- }
- last = a;
- }
-
- new_action = xzalloc(sizeof(struct init_action));
- if (last) {
- last->next = new_action;
- } else {
- init_action_list = new_action;
- }
- strcpy(new_action->command, command);
- new_action->action = action;
- strcpy(new_action->terminal, cons);
- messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
- new_action->command, new_action->action, new_action->terminal);
-}
-
-static void delete_init_action(struct init_action *action)
-{
- struct init_action *a, *b = NULL;
+#ifdef RB_ENABLE_CAD
+ /* Allow Ctrl-Alt-Del to reboot the system.
+ * This is how kernel sets it up for init, we follow suit.
+ */
+ reboot(RB_ENABLE_CAD); /* misnomer */
+#endif
- for (a = init_action_list; a; b = a, a = a->next) {
- if (a == action) {
- if (b == NULL) {
- init_action_list = a->next;
- } else {
- b->next = a->next;
- }
- free(a);
- break;
+ if (open_stdio_to_tty(a->terminal)) {
+ dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
+ /* Theoretically should be safe.
+ * But in practice, kernel bugs may leave
+ * unkillable processes, and wait() may block forever.
+ * Oh well. Hoping "new" init won't be too surprised
+ * by having children it didn't create.
+ */
+ //while (wait(NULL) > 0)
+ // continue;
+ init_exec(a->command);
}
+ /* Open or exec failed */
+ pause_and_low_level_reboot(RB_HALT_SYSTEM);
+ /* not reached */
}
}
-/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
- * then parse_inittab() simply adds in some default
- * actions(i.e., runs INIT_SCRIPT and then starts a pair
- * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
- * _is_ defined, but /etc/inittab is missing, this
- * results in the same set of default behaviors.
+/* The SIGSTOP/SIGTSTP handler
+ * NB: inside it, all signals except SIGCONT are masked
+ * via appropriate setup in sigaction().
*/
-static void parse_inittab(void)
+static void stop_handler(int sig UNUSED_PARAM)
{
- FILE *file;
- char buf[INIT_BUFFS_SIZE];
+ smallint saved_bb_got_signal;
+ int saved_errno;
- if (ENABLE_FEATURE_USE_INITTAB)
- file = fopen(INITTAB, "r");
- else
- file = NULL;
+ saved_bb_got_signal = bb_got_signal;
+ saved_errno = errno;
+ signal(SIGCONT, record_signo);
- /* No inittab file -- set up some default behavior */
- if (file == NULL) {
- /* Reboot on Ctrl-Alt-Del */
- new_init_action(CTRLALTDEL, "reboot", "");
- /* Umount all filesystems on halt/reboot */
- new_init_action(SHUTDOWN, "umount -a -r", "");
- /* Swapoff on halt/reboot */
- if (ENABLE_SWAPONOFF)
- new_init_action(SHUTDOWN, "swapoff -a", "");
- /* Prepare to restart init when a HUP is received */
- new_init_action(RESTART, "init", "");
- /* Askfirst shell on tty1-4 */
- new_init_action(ASKFIRST, bb_default_login_shell, "");
- new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
- new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
- new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
- /* sysinit */
- new_init_action(SYSINIT, INIT_SCRIPT, "");
+ while (1) {
+ pid_t wpid;
- return;
+ if (bb_got_signal == SIGCONT)
+ break;
+ /* NB: this can accidentally wait() for a process
+ * which we waitfor() elsewhere! waitfor() must have
+ * code which is resilient against this.
+ */
+ wpid = wait_any_nohang(NULL);
+ mark_terminated(wpid);
+ sleep(1);
}
- while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
- static const char actions[] =
- STR_SYSINIT "sysinit\0"
- STR_RESPAWN "respawn\0"
- STR_ASKFIRST "askfirst\0"
- STR_WAIT "wait\0"
- STR_ONCE "once\0"
- STR_CTRLALTDEL "ctrlaltdel\0"
- STR_SHUTDOWN "shutdown\0"
- STR_RESTART "restart\0"
- ;
- char tmpConsole[CONSOLE_NAME_SIZE];
- char *id, *runlev, *action, *command;
- const char *a;
-
- /* Skip leading spaces */
- id = skip_whitespace(buf);
- /* Skip the line if it's a comment */
- if (*id == '#' || *id == '\n')
- continue;
- /* Trim the trailing '\n' */
- *strchrnul(id, '\n') = '\0';
-
- /* Line is: "id:runlevel_ignored:action:command" */
- runlev = strchr(id, ':');
- if (runlev == NULL /*|| runlev[1] == '\0' - not needed */)
- goto bad_entry;
- action = strchr(runlev + 1, ':');
- if (action == NULL /*|| action[1] == '\0' - not needed */)
- goto bad_entry;
- command = strchr(action + 1, ':');
- if (command == NULL || command[1] == '\0')
- goto bad_entry;
-
- *command = '\0'; /* action => ":action\0" now */
- for (a = actions; a[0]; a += strlen(a) + 1) {
- if (strcmp(a + 1, action + 1) == 0) {
- *runlev = '\0';
- if (*id != '\0') {
- if (strncmp(id, "/dev/", 5) == 0)
- id += 5;
- strcpy(tmpConsole, "/dev/");
- safe_strncpy(tmpConsole + 5, id,
- sizeof(tmpConsole) - 5);
- id = tmpConsole;
- }
- new_init_action((uint8_t)a[0], command + 1, id);
- goto next_line;
- }
- }
- *command = ':';
- /* Choke on an unknown action */
- bad_entry:
- message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", id);
- next_line: ;
- }
- fclose(file);
+ signal(SIGCONT, SIG_DFL);
+ errno = saved_errno;
+ bb_got_signal = saved_bb_got_signal;
}
-static void reload_signal(int sig ATTRIBUTE_UNUSED)
+#if ENABLE_FEATURE_USE_INITTAB
+static void reload_inittab(void)
{
- struct init_action *a, *tmp;
+ struct init_action *a, **nextp;
message(L_LOG, "reloading /etc/inittab");
- /* disable old entrys */
- for (a = init_action_list; a; a = a->next) {
- a->action = ONCE;
- }
+ /* Disable old entries */
+ for (a = init_action_list; a; a = a->next)
+ a->action_type = 0;
+ /* Append new entries, or modify existing entries
+ * (incl. setting a->action_type) if cmd and device name
+ * match new ones. End result: only entries with
+ * a->action_type == 0 are stale.
+ */
parse_inittab();
- if (ENABLE_FEATURE_KILL_REMOVED) {
- for (a = init_action_list; a; a = a->next) {
- pid_t pid = a->pid;
- if ((a->action & ONCE) && pid != 0) {
- /* Be nice and send SIGTERM first */
- kill(pid, SIGTERM);
- if (CONFIG_FEATURE_KILL_DELAY)
- if (fork() == 0) { /* child */
- sleep(CONFIG_FEATURE_KILL_DELAY);
- kill(pid, SIGKILL);
- _exit(0);
- }
- }
+#if ENABLE_FEATURE_KILL_REMOVED
+ /* Kill stale entries */
+ /* Be nice and send SIGTERM first */
+ for (a = init_action_list; a; a = a->next)
+ if (a->action_type == 0 && a->pid != 0)
+ kill(a->pid, SIGTERM);
+ if (CONFIG_FEATURE_KILL_DELAY) {
+ /* NB: parent will wait in NOMMU case */
+ if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
+ sleep(CONFIG_FEATURE_KILL_DELAY);
+ for (a = init_action_list; a; a = a->next)
+ if (a->action_type == 0 && a->pid != 0)
+ kill(a->pid, SIGKILL);
+ _exit(EXIT_SUCCESS);
}
}
+#endif
- /* remove unused entrys */
- for (a = init_action_list; a; a = tmp) {
- tmp = a->next;
- if ((a->action & (ONCE | SYSINIT | WAIT)) && a->pid == 0) {
- delete_init_action(a);
+ /* Remove stale entries and SYSINIT entries.
+ * We never rerun SYSINIT entries anyway,
+ * removing them too saves a few bytes */
+ nextp = &init_action_list;
+ while ((a = *nextp) != NULL) {
+ if ((a->action_type & ~SYSINIT) == 0) {
+ *nextp = a->next;
+ free(a);
+ } else {
+ nextp = &a->next;
}
}
- run_actions(RESPAWN);
+
+ /* Not needed: */
+ /* run_actions(RESPAWN | ASKFIRST); */
+ /* - we return to main loop, which does this automagically */
}
+#endif
-int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int init_main(int argc, char **argv)
+static int check_delayed_sigs(void)
{
- struct init_action *a;
- pid_t wpid;
+ int sigs_seen = 0;
- die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */
+ while (1) {
+ smallint sig = bb_got_signal;
+
+ if (!sig)
+ return sigs_seen;
+ bb_got_signal = 0;
+ sigs_seen = 1;
+#if ENABLE_FEATURE_USE_INITTAB
+ if (sig == SIGHUP)
+ reload_inittab();
+#endif
+ if (sig == SIGINT)
+ run_actions(CTRLALTDEL);
+ }
+}
- if (argc > 1 && !strcmp(argv[1], "-q")) {
+int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int init_main(int argc UNUSED_PARAM, char **argv)
+{
+ if (argv[1] && strcmp(argv[1], "-q") == 0) {
return kill(1, SIGHUP);
}
- if (!ENABLE_DEBUG_INIT) {
+ if (!DEBUG_INIT) {
/* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
if (getpid() != 1
- && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
+ && (!ENABLE_FEATURE_INITRD || applet_name[0] != 'l') /* not linuxrc? */
) {
- bb_show_usage();
+ bb_error_msg_and_die("must be run as PID 1");
}
- /* Set up sig handlers -- be sure to
- * clear all of these in run() */
- signal(SIGHUP, exec_signal);
- signal(SIGQUIT, exec_signal);
- signal(SIGUSR1, shutdown_signal);
- signal(SIGUSR2, shutdown_signal);
- signal(SIGINT, ctrlaltdel_signal);
- signal(SIGTERM, shutdown_signal);
- signal(SIGCONT, cont_handler);
- signal(SIGSTOP, stop_handler);
- signal(SIGTSTP, stop_handler);
-
- /* Turn off rebooting via CTL-ALT-DEL -- we get a
+#ifdef RB_DISABLE_CAD
+ /* Turn off rebooting via CTL-ALT-DEL - we get a
* SIGINT on CAD so we can shut things down gracefully... */
- init_reboot(RB_DISABLE_CAD);
+ reboot(RB_DISABLE_CAD); /* misnomer */
+#endif
}
+ /* If, say, xmalloc would ever die, we don't want to oops kernel
+ * by exiting.
+ * NB: we set die_sleep *after* PID 1 check and bb_show_usage.
+ * Otherwise, for example, "init u" ("please rexec yourself"
+ * command for sysvinit) will show help text (which isn't too bad),
+ * *and sleep forever* (which is bad!)
+ */
+ die_sleep = 30 * 24*60*60;
+
/* Figure out where the default console should be */
console_init();
set_sane_term();
- chdir("/");
+ xchdir("/");
setsid();
- {
- const char *const *e;
- /* Make sure environs is set to something sane */
- for (e = environment; *e; e++)
- putenv((char *) *e);
- }
- if (argc > 1) setenv("RUNLEVEL", argv[1], 1);
+ /* Make sure environs is set to something sane */
+ putenv((char *) "HOME=/");
+ putenv((char *) bb_PATH_root_path);
+ putenv((char *) "SHELL=/bin/sh");
+ putenv((char *) "USER=root"); /* needed? why? */
+ if (argv[1])
+ xsetenv("RUNLEVEL", argv[1]);
+
+#if !ENABLE_FEATURE_EXTRA_QUIET
/* Hello world */
- message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
+ message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
+#endif
+/* struct sysinfo is linux-specific */
+#ifdef __linux__
/* Make sure there is enough memory to do something useful. */
if (ENABLE_SWAPONOFF) {
struct sysinfo info;
- if (!sysinfo(&info) &&
- (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
- {
+ if (sysinfo(&info) == 0
+ && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024
+ ) {
message(L_CONSOLE, "Low memory, forcing swapon");
/* swapon -a requires /proc typically */
new_init_action(SYSINIT, "mount -t proc proc /proc", "");
run_actions(SYSINIT); /* wait and removing */
}
}
+#endif
/* Check if we are supposed to be in single user mode */
- if (argc > 1
- && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
+ if (argv[1]
+ && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1'))
) {
+ /* ??? shouldn't we set RUNLEVEL="b" here? */
/* Start a shell on console */
new_init_action(RESPAWN, bb_default_login_shell, "");
} else {
- /* Not in single user mode -- see what inittab says */
+ /* Not in single user mode - see what inittab says */
/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
* then parse_inittab() simply adds in some default
- * actions(i.e., runs INIT_SCRIPT and then starts a pair
+ * actions(i.e., INIT_SCRIPT and a pair
* of "askfirst" shells */
parse_inittab();
}
BB_EXECVP(argv[0], argv);
} else if (enforce > 0) {
/* SELinux in enforcing mode but load_policy failed */
- message(L_CONSOLE, "Cannot load SELinux Policy. "
+ message(L_CONSOLE, "can't load SELinux Policy. "
"Machine is in enforcing mode. Halting now.");
- exit(1);
+ return EXIT_FAILURE;
}
}
-#endif /* CONFIG_SELINUX */
+#endif
/* Make the command line just say "init" - thats all, nothing else */
strncpy(argv[0], "init", strlen(argv[0]));
while (*++argv)
memset(*argv, 0, strlen(*argv));
- /* Now run everything that needs to be run */
+ /* Set up signal handlers */
+ if (!DEBUG_INIT) {
+ struct sigaction sa;
+
+ bb_signals(0
+ + (1 << SIGUSR1) /* halt */
+ + (1 << SIGTERM) /* reboot */
+ + (1 << SIGUSR2) /* poweroff */
+ , halt_reboot_pwoff);
+ signal(SIGQUIT, restart_handler); /* re-exec another init */
+
+ /* Stop handler must allow only SIGCONT inside itself */
+ memset(&sa, 0, sizeof(sa));
+ sigfillset(&sa.sa_mask);
+ sigdelset(&sa.sa_mask, SIGCONT);
+ sa.sa_handler = stop_handler;
+ /* NB: sa_flags doesn't have SA_RESTART.
+ * It must be able to interrupt wait().
+ */
+ sigaction_set(SIGTSTP, &sa); /* pause */
+ /* Does not work as intended, at least in 2.6.20.
+ * SIGSTOP is simply ignored by init:
+ */
+ sigaction_set(SIGSTOP, &sa); /* pause */
+
+ /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
+ * setting handler without SA_RESTART flag.
+ */
+ bb_signals_recursive_norestart((1 << SIGINT), record_signo);
+ }
+
+ /* Set up "reread /etc/inittab" handler.
+ * Handler is set up without SA_RESTART, it will interrupt syscalls.
+ */
+ if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
+ bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
+ /* Now run everything that needs to be run */
/* First run the sysinit command */
run_actions(SYSINIT);
-
+ check_delayed_sigs();
/* Next run anything that wants to block */
run_actions(WAIT);
-
+ check_delayed_sigs();
/* Next run anything to be run only once */
run_actions(ONCE);
- /* Redefine SIGHUP to reread /etc/inittab */
- if (ENABLE_FEATURE_USE_INITTAB)
- signal(SIGHUP, reload_signal);
- else
- signal(SIGHUP, SIG_IGN);
-
- /* Now run the looping stuff for the rest of forever */
+ /* Now run the looping stuff for the rest of forever.
+ */
while (1) {
- /* run the respawn stuff */
- run_actions(RESPAWN);
+ int maybe_WNOHANG;
- /* run the askfirst stuff */
- run_actions(ASKFIRST);
+ maybe_WNOHANG = check_delayed_sigs();
- /* Don't consume all CPU time -- sleep a bit */
- sleep(1);
+ /* (Re)run the respawn/askfirst stuff */
+ run_actions(RESPAWN | ASKFIRST);
+ maybe_WNOHANG |= check_delayed_sigs();
- /* Wait for a child process to exit */
- wpid = wait(NULL);
- while (wpid > 0) {
- /* Find out who died and clean up their corpse */
- for (a = init_action_list; a; a = a->next) {
- if (a->pid == wpid) {
- /* Set the pid to 0 so that the process gets
- * restarted by run_actions() */
- a->pid = 0;
- message(L_LOG, "process '%s' (pid %d) exited. "
- "Scheduling it for restart.",
- a->command, wpid);
- }
+ /* Don't consume all CPU time - sleep a bit */
+ sleep(1);
+ maybe_WNOHANG |= check_delayed_sigs();
+
+ /* Wait for any child process(es) to exit.
+ *
+ * If check_delayed_sigs above reported that a signal
+ * was caught, wait will be nonblocking. This ensures
+ * that if SIGHUP has reloaded inittab, respawn and askfirst
+ * actions will not be delayed until next child death.
+ */
+ if (maybe_WNOHANG)
+ maybe_WNOHANG = WNOHANG;
+ while (1) {
+ pid_t wpid;
+ struct init_action *a;
+
+ /* If signals happen _in_ the wait, they interrupt it,
+ * bb_signals_recursive_norestart set them up that way
+ */
+ wpid = waitpid(-1, NULL, maybe_WNOHANG);
+ if (wpid <= 0)
+ break;
+
+ a = mark_terminated(wpid);
+ if (a) {
+ message(L_LOG, "process '%s' (pid %d) exited. "
+ "Scheduling for restart.",
+ a->command, wpid);
}
- /* see if anyone else is waiting to be reaped */
- wpid = waitpid(-1, NULL, WNOHANG);
+ /* See if anyone else is waiting to be reaped */
+ maybe_WNOHANG = WNOHANG;
}
- }
+ } /* while (1) */
}
+
+//usage:#define linuxrc_trivial_usage NOUSAGE_STR
+//usage:#define linuxrc_full_usage ""
+
+//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"
projects / oweals / busybox.git / blobdiff