/* vi: set sw=4 ts=4: */ /* * Mini init implementation for busybox * * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>. * 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. */ #include "busybox.h" #include <paths.h> #include <signal.h> #include <sys/ioctl.h> #include <sys/wait.h> #include <sys/reboot.h> #if ENABLE_FEATURE_INIT_SYSLOG # include <sys/syslog.h> #endif #define INIT_BUFFS_SIZE 256 #define CONSOLE_NAME_SIZE 32 #define MAXENV 16 /* Number of env. vars */ #ifndef _PATH_STDPATH #define _PATH_STDPATH "/usr/bin:/bin:/usr/sbin:/sbin" #endif #if ENABLE_FEATURE_INIT_COREDUMPS /* * 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.... */ #define CORE_ENABLE_FLAG_FILE "/.init_enable_core" #include <sys/resource.h> #endif #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 /* A mapping between "inittab" action name strings and action type codes. */ struct init_action_type { const char *name; int action; }; static const struct init_action_type actions[] = { {"sysinit", SYSINIT}, {"respawn", RESPAWN}, {"askfirst", ASKFIRST}, {"wait", WAIT}, {"once", ONCE}, {"ctrlaltdel", CTRLALTDEL}, {"shutdown", SHUTDOWN}, {"restart", RESTART}, {0, 0} }; /* Set up a linked list of init_actions, to be read from inittab */ struct init_action { struct init_action *next; int action; pid_t pid; char command[INIT_BUFFS_SIZE]; char terminal[CONSOLE_NAME_SIZE]; }; /* Static variables */ static struct init_action *init_action_list = NULL; #if !ENABLE_FEATURE_INIT_SYSLOG static const char *log_console = VC_5; #endif #if !ENABLE_DEBUG_INIT static sig_atomic_t got_cont = 0; #endif 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=/", "PATH=" _PATH_STDPATH, "SHELL=/bin/sh", "USER=root", NULL }; /* Function prototypes */ static void delete_init_action(struct init_action *a); static int waitfor(const struct init_action *a, pid_t pid); #if !ENABLE_DEBUG_INIT static void shutdown_signal(int sig); #endif #if !ENABLE_DEBUG_INIT static void loop_forever(void) { while (1) sleep(1); } #endif /* Print a message to the specified device. * Device may be bitwise-or'd from L_LOG | L_CONSOLE */ #if ENABLE_DEBUG_INIT #define messageD message #else #define messageD(...) do {} while (0) #endif static void message(int device, const char *fmt, ...) __attribute__ ((format(printf, 2, 3))); static void message(int device, const char *fmt, ...) { #if !ENABLE_FEATURE_INIT_SYSLOG static int log_fd = -1; #endif va_list arguments; int l; char msg[128]; msg[0] = '\r'; va_start(arguments, fmt); vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments); va_end(arguments); msg[sizeof(msg) - 2] = '\0'; l = strlen(msg); #if ENABLE_FEATURE_INIT_SYSLOG /* 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 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; } 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; } else { fcntl(log_fd, F_SETFD, FD_CLOEXEC); } } } if (device & L_LOG) { full_write(log_fd, msg, l); if (log_fd == 2) return; /* don't print dup messages */ } #endif if (device & L_CONSOLE) { /* Send console messages to console so people will see them. */ full_write(2, msg, l); } } /* Set terminal settings to reasonable defaults */ static void set_sane_term(void) { struct termios tty; tcgetattr(STDIN_FILENO, &tty); /* set control chars */ tty.c_cc[VINTR] = 3; /* C-c */ tty.c_cc[VQUIT] = 28; /* C-\ */ tty.c_cc[VERASE] = 127; /* C-? */ tty.c_cc[VKILL] = 21; /* C-u */ tty.c_cc[VEOF] = 4; /* C-d */ tty.c_cc[VSTART] = 17; /* C-q */ tty.c_cc[VSTOP] = 19; /* C-s */ tty.c_cc[VSUSP] = 26; /* C-z */ /* use line dicipline 0 */ tty.c_line = 0; /* Make it be sane */ tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD; tty.c_cflag |= CREAD | HUPCL | CLOCAL; /* input modes */ tty.c_iflag = ICRNL | IXON | IXOFF; /* output modes */ tty.c_oflag = OPOST | ONLCR; /* local modes */ tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN; tcsetattr(STDIN_FILENO, TCSANOW, &tty); } /* 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; char *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--); } messageD(L_LOG, "console='%s'", s); } s = getenv("TERM"); if (ioctl(0, TIOCGSERIAL, &sr) == 0) { /* Force the TERM setting to vt102 for serial console -- * 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; #endif } else if (!s) putenv((char*)"TERM=linux"); } static void fixup_argv(int argc, char **argv, const char *new_argv0) { int len; /* Fix up argv[0] to be certain we claim to be init */ len = strlen(argv[0]); strncpy(argv[0], new_argv0, len); /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */ len = 1; while (argc > len) { memset(argv[len], 0, strlen(argv[len])); len++; } } /* Open the new terminal device */ static void open_stdio_to_tty(const char* tty_name, int fail) { /* 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", tty_name, strerror(errno)); if (fail) _exit(1); #if !ENABLE_DEBUG_INIT shutdown_signal(SIGUSR1); #else _exit(2); #endif } else { dup2(fd, 0); dup2(fd, 1); dup2(fd, 2); if (fd > 2) close(fd); } } set_sane_term(); } static pid_t run(const struct init_action *a) { 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. */ sigemptyset(&nmask); sigaddset(&nmask, SIGCHLD); sigprocmask(SIG_BLOCK, &nmask, &omask); pid = fork(); sigprocmask(SIG_SETMASK, &omask, NULL); if (pid) return pid; /* 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); /* If the init Action requires us to wait, then force the * supplied terminal to be the controlling tty. */ if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) { /* Now fork off another process to just hang around */ if ((pid = fork()) < 0) { message(L_LOG | L_CONSOLE, "Can't fork"); _exit(1); } if (pid > 0) { /* We are the parent -- wait till the child is done */ signal(SIGINT, SIG_IGN); signal(SIGTSTP, SIG_IGN); signal(SIGQUIT, SIG_IGN); signal(SIGCHLD, SIG_DFL); waitfor(NULL, 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. */ if ((pid = fork()) < 0) { message(L_LOG | L_CONSOLE, "Can't fork"); _exit(1); } if (pid == 0) { setsid(); ioctl(0, TIOCSCTTY, 1); _exit(0); } waitfor(NULL, pid); _exit(0); } /* Now fall though to actually execute things */ } /* See if any special /bin/sh requiring characters are present */ if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) { cmd[0] = (char*)DEFAULT_SHELL; cmd[1] = (char*)"-c"; cmd[2] = strcat(strcpy(buf, "exec "), a->command); cmd[3] = NULL; } 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; 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 (*cmdpath == '-') { /* skip over the dash */ ++cmdpath; /* find the last component in the command pathname */ s = bb_get_last_path_component(cmdpath); /* make a new argv[0] */ if ((cmd[0] = malloc(strlen(s) + 2)) == NULL) { message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted); cmd[0] = cmdpath; } else { cmd[0][0] = '-'; strcpy(cmd[0] + 1, s); } #if ENABLE_FEATURE_INIT_SCTTY /* Establish this process as session leader and * (attempt) to make the tty (if any) a controlling tty. */ setsid(); ioctl(0, TIOCSCTTY, 0 /*don't steal it*/); #endif } #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__) if (a->action & ASKFIRST) { static const char press_enter[] = #ifdef CUSTOMIZED_BANNER #include CUSTOMIZED_BANNER #endif "\nPlease press Enter to activate this console. "; char c; /* * Save memory by not exec-ing anything large (like a shell) * before the user wants it. This is critical if swap is not * enabled and the system has low memory. Generally this will * be run on the second virtual console, and the first will * be allowed to start a shell or whatever an init script * specifies. */ messageD(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 (read(0, &c, 1) == 1 && c != '\n') ; } #endif /* Log the process name and args */ message(L_LOG, "starting pid %d, tty '%s': '%s'", getpid(), a->terminal, cmdpath); #if ENABLE_FEATURE_INIT_COREDUMPS { struct stat sb; if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) { struct rlimit limit; limit.rlim_cur = RLIM_INFINITY; limit.rlim_max = RLIM_INFINITY; setrlimit(RLIMIT_CORE, &limit); } } #endif /* Now run it. The new program will take over this PID, * so nothing further in init.c should be run. */ BB_EXECVP(cmdpath, cmd); /* We're still here? Some error happened. */ message(L_LOG | L_CONSOLE, "Cannot run '%s': %s", cmdpath, strerror(errno)); _exit(-1); } static int waitfor(const struct init_action *a, pid_t pid) { int runpid; int status, wpid; runpid = (NULL == a)? pid : run(a); while (1) { wpid = waitpid(runpid, &status, 0); if (wpid == runpid) break; if (wpid == -1 && errno == ECHILD) { /* we missed its termination */ break; } /* FIXME other errors should maybe trigger an error, but allow * the program to continue */ } return wpid; } /* Run all commands of a particular type */ static void run_actions(int action) { struct init_action *a, *tmp; for (a = init_action_list; a; a = tmp) { tmp = a->next; if (a->action == action) { /* a->terminal of "" means "init's console" */ if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) { delete_init_action(a); } else if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) { waitfor(a, 0); 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); } } } } } #if !ENABLE_DEBUG_INIT static void init_reboot(unsigned long 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.... */ pid = vfork(); if (pid == 0) { /* child */ reboot(magic); _exit(0); } waitpid(pid, NULL, 0); } static void shutdown_system(void) { sigset_t block_signals; /* 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); sync(); sleep(1); message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL"); kill(-1, SIGKILL); sync(); sleep(1); } 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); 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(); } } } static void shutdown_signal(int sig) { const char *m; int rb; shutdown_system(); m = "halt"; rb = RB_HALT_SYSTEM; if (sig == SIGTERM) { m = "reboot"; rb = RB_AUTOBOOT; } else if (sig == SIGUSR2) { 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 ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED) { 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(); got_cont = 0; errno = saved_errno; } /* The SIGCONT handler */ static void cont_handler(int sig ATTRIBUTE_UNUSED) { got_cont = 1; } #endif /* !ENABLE_DEBUG_INIT */ static void new_init_action(int action, const char *command, const char *cons) { struct init_action *new_action, *a, *last; if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST)) return; /* 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; 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; } } } /* 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 FILE *file; char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE]; char tmpConsole[CONSOLE_NAME_SIZE]; char *id, *runlev, *action, *command, *eol; const struct init_action_type *a = actions; file = fopen(INITTAB, "r"); if (file == NULL) { /* No inittab file -- set up some default behavior */ #endif /* 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, ""); return; #if ENABLE_FEATURE_USE_INITTAB } while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) { /* Skip leading spaces */ for (id = buf; *id == ' ' || *id == '\t'; id++); /* Skip the line if it's a comment */ if (*id == '#' || *id == '\n') continue; /* Trim the trailing \n */ //XXX: chomp() ? eol = strrchr(id, '\n'); if (eol != NULL) *eol = '\0'; /* Keep a copy around for posterity's sake (and error msgs) */ strcpy(lineAsRead, buf); /* Separate the ID field from the runlevels */ runlev = strchr(id, ':'); if (runlev == NULL || *(runlev + 1) == '\0') { message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead); continue; } else { *runlev = '\0'; ++runlev; } /* Separate the runlevels from the action */ action = strchr(runlev, ':'); if (action == NULL || *(action + 1) == '\0') { message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead); continue; } else { *action = '\0'; ++action; } /* Separate the action from the command */ command = strchr(action, ':'); if (command == NULL || *(command + 1) == '\0') { message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead); continue; } else { *command = '\0'; ++command; } /* Ok, now process it */ for (a = actions; a->name != 0; a++) { if (strcmp(a->name, action) == 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(a->action, command, id); break; } } if (a->name == 0) { /* Choke on an unknown action */ message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead); } } fclose(file); #endif /* FEATURE_USE_INITTAB */ } #if ENABLE_FEATURE_USE_INITTAB static void reload_signal(int sig ATTRIBUTE_UNUSED) { struct init_action *a, *tmp; message(L_LOG, "reloading /etc/inittab"); /* disable old entrys */ for (a = init_action_list; a; a = a->next ) { a->action = ONCE; } parse_inittab(); /* 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); } } run_actions(RESPAWN); } #endif /* FEATURE_USE_INITTAB */ int init_main(int argc, char **argv); int init_main(int argc, char **argv) { struct init_action *a; pid_t wpid; die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */ if (argc > 1 && !strcmp(argv[1], "-q")) { return kill(1, SIGHUP); } #if !ENABLE_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")) ) { bb_show_usage(); } /* 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 * SIGINT on CAD so we can shut things down gracefully... */ init_reboot(RB_DISABLE_CAD); #endif /* Figure out where the default console should be */ console_init(); set_sane_term(); chdir("/"); 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); /* Hello world */ message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_msg_full_version); /* 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) { message(L_CONSOLE, "Low memory, forcing swapon"); /* swapon -a requires /proc typically */ new_init_action(SYSINIT, "mount -t proc proc /proc", ""); /* Try to turn on swap */ new_init_action(SYSINIT, "swapon -a", ""); run_actions(SYSINIT); /* wait and removing */ } } /* 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')) ) { /* Start a shell on console */ new_init_action(RESPAWN, bb_default_login_shell, ""); } else { /* 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 * of "askfirst" shells */ parse_inittab(); } #if ENABLE_SELINUX if (getenv("SELINUX_INIT") == NULL) { int enforce = 0; putenv("SELINUX_INIT=YES"); if (selinux_init_load_policy(&enforce) == 0) { BB_EXECVP(argv[0], argv); } else if (enforce > 0) { /* SELinux in enforcing mode but load_policy failed */ /* At this point, we probably can't open /dev/console, so log() won't work */ message(L_CONSOLE, "Cannot load SELinux Policy. " "Machine is in enforcing mode. Halting now."); exit(1); } } #endif /* CONFIG_SELINUX */ /* Make the command line just say "init" -- thats all, nothing else */ fixup_argv(argc, argv, "init"); /* Now run everything that needs to be run */ /* First run the sysinit command */ run_actions(SYSINIT); /* Next run anything that wants to block */ run_actions(WAIT); /* Next run anything to be run only once */ run_actions(ONCE); #if ENABLE_FEATURE_USE_INITTAB /* Redefine SIGHUP to reread /etc/inittab */ signal(SIGHUP, reload_signal); #else signal(SIGHUP, SIG_IGN); #endif /* FEATURE_USE_INITTAB */ /* Now run the looping stuff for the rest of forever */ while (1) { /* run the respawn stuff */ run_actions(RESPAWN); /* run the askfirst stuff */ run_actions(ASKFIRST); /* Don't consume all CPU time -- sleep a bit */ sleep(1); /* 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); } } /* see if anyone else is waiting to be reaped */ wpid = waitpid(-1, NULL, WNOHANG); } } }