/* * Mini init implementation for busybox * * * Copyright (C) 1995, 1996 by Bruce Perens . * Adjusted by so many folks, it's impossible to keep track. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include "internal.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for serial_struct */ #include /* for vt_stat */ #include #include #ifdef BB_SYSLOGD #include #endif #if ! defined BB_FEATURE_USE_PROCFS #error Sorry, I depend on the /proc filesystem right now. #endif #ifndef KERNEL_VERSION #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) #endif #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */ #define VT_SECONDARY "/dev/tty2" /* Virtual console */ #define VT_LOG "/dev/tty3" /* Virtual console */ #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */ #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */ #define SHELL "-sh" /* Default shell */ #define INITTAB "/etc/inittab" /* inittab file location */ #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */ #define LOG 0x1 #define CONSOLE 0x2 /* Allowed init action types */ typedef enum { SYSINIT=1, RESPAWN, ASKFIRST, WAIT, ONCE } initActionEnum; /* And now a list of the actions we support in the version of init */ typedef struct initActionType{ const char* name; initActionEnum action; } initActionType; static const struct initActionType actions[] = { {"sysinit", SYSINIT}, {"respawn", RESPAWN}, {"askfirst", ASKFIRST}, {"wait", WAIT}, {"once", ONCE}, {0} }; /* Set up a linked list of initactions, to be read from inittab */ typedef struct initActionTag initAction; struct initActionTag { pid_t pid; char process[256]; char console[256]; initAction *nextPtr; initActionEnum action; }; initAction* initActionList = NULL; static char *console = _PATH_CONSOLE; static char *second_console = VT_SECONDARY; static char *log = VT_LOG; static int kernel_version = 0; /* try to open up the specified device */ int device_open(char *device, int mode) { int m, f, fd = -1; m = mode | O_NONBLOCK; /* Retry up to 5 times */ for (f = 0; f < 5; f++) if ((fd = open(device, m)) >= 0) break; if (fd < 0) return fd; /* Reset original flags. */ if (m != mode) fcntl(fd, F_SETFL, mode); return fd; } /* print a message to the specified device: * device may be bitwise-or'd from LOG | CONSOLE */ void message(int device, char *fmt, ...) { va_list arguments; int fd; #ifdef BB_SYSLOGD /* Log the message to syslogd */ if (device & LOG ) { char msg[1024]; va_start(arguments, fmt); vsnprintf(msg, sizeof(msg), fmt, arguments); va_end(arguments); syslog(LOG_DAEMON|LOG_NOTICE, msg); } #else static int log_fd=-1; /* Take full control of the log tty, and never close it. * It's mine, all mine! Muhahahaha! */ if (log_fd < 0) { if (log == NULL) { /* don't even try to log, because there is no such console */ log_fd = -2; /* log to main console instead */ device = CONSOLE; } else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) { log_fd=-1; fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log); fflush(stderr); return; } } if ( (device & LOG) && (log_fd >= 0) ) { va_start(arguments, fmt); vdprintf(log_fd, fmt, arguments); va_end(arguments); } #endif if (device & CONSOLE) { /* Always send console messages to /dev/console so people will see them. */ if ((fd = device_open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) { va_start(arguments, fmt); vdprintf(fd, fmt, arguments); va_end(arguments); close(fd); } else { fprintf(stderr, "Bummer, can't print: "); va_start(arguments, fmt); vfprintf(stderr, fmt, arguments); fflush(stderr); va_end(arguments); } } } /* Set terminal settings to reasonable defaults */ void set_term( int fd) { struct termios tty; static const char control_characters[] = { '\003', '\034', '\177', '\025', '\004', '\0', '\1', '\0', '\021', '\023', '\032', '\0', '\022', '\017', '\027', '\026', '\0' }; tcgetattr(fd, &tty); /* set control chars */ memcpy(tty.c_cc, control_characters, sizeof(control_characters)); /* use line dicipline 0 */ tty.c_line = 0; /* Make it be sane */ //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD; //tty.c_cflag |= 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(fd, TCSANOW, &tty); } /* How much memory does this machine have? */ static int mem_total() { char s[80]; char *p = "/proc/meminfo"; FILE *f; const char pattern[] = "MemTotal:"; if ((f = fopen(p, "r")) < 0) { message(LOG, "Error opening %s: %s\n", p, strerror( errno)); return -1; } while (NULL != fgets(s, 79, f)) { p = strstr(s, pattern); if (NULL != p) { fclose(f); return (atoi(p + strlen(pattern))); } } return -1; } static void console_init() { int fd; int tried_devcons = 0; int tried_vtprimary = 0; struct serial_struct sr; char *s; if ((s = getenv("CONSOLE")) != NULL) { console = s; } #if #cpu(sparc) /* sparc kernel supports console=tty[ab] parameter which is also * passed to init, so catch it here */ else if ((s = getenv("console")) != NULL) { /* remap tty[ab] to /dev/ttyS[01] */ if (strcmp( s, "ttya" )==0) console = SERIAL_CON0; else if (strcmp( s, "ttyb" )==0) console = SERIAL_CON1; } #endif else { struct vt_stat vt; static char the_console[13]; console = the_console; /* 2.2 kernels: identify the real console backend and try to use it */ if (ioctl(0, TIOCGSERIAL, &sr) == 0) { /* this is a serial console */ snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line ); } else if (ioctl(0, VT_GETSTATE, &vt) == 0) { /* this is linux virtual tty */ snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active ); } else { console = _PATH_CONSOLE; tried_devcons++; } } while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) { /* Can't open selected console -- try /dev/console */ if (!tried_devcons) { tried_devcons++; console = _PATH_CONSOLE; continue; } /* Can't open selected console -- try vt1 */ if (!tried_vtprimary) { tried_vtprimary++; console = VT_PRIMARY; continue; } break; } if (fd < 0) /* Perhaps we should panic here? */ console = "/dev/null"; else { /* check for serial console and disable logging to tty3 & running a * shell to tty2 */ if (ioctl(0,TIOCGSERIAL,&sr) == 0) { message(LOG|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console ); log = NULL; second_console = NULL; } close(fd); } message(LOG, "console=%s\n", console ); } static int waitfor(int pid) { int status, wpid; while (1) { wpid = wait(&status); if (wpid > 0 ) { message(LOG, "pid %d exited, status=0x%x.\n", wpid, status); break; } if (wpid == pid ) break; } return wpid; } static pid_t run(char* command, char *terminal, int get_enter) { int i; pid_t pid; char* tmpCmd; char* cmd[255]; static const char press_enter[] = "\nPlease press Enter to activate this console. "; if ((pid = fork()) == 0) { pid_t shell_pgid = getpid (); /* Clean up */ close(0); close(1); close(2); setsid(); if (device_open(terminal, O_RDWR) < 0) { message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal); exit(1); } dup(0); dup(0); /* Grab control of the terminal. */ if (tcsetpgrp (0, getpgrp()) < 0) { message(LOG|CONSOLE, "tcsetpgrp error: %s\r\n", strerror(errno)); } set_term(0); /* Reset signal handlers set for parent process */ signal(SIGUSR1, SIG_DFL); signal(SIGUSR2, SIG_DFL); signal(SIGINT, SIG_DFL); signal(SIGTERM, SIG_DFL); if (get_enter==TRUE) { /* * 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. */ char c; message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n", command, shell_pgid, terminal ); write(fileno(stdout), press_enter, sizeof(press_enter) - 1); read(fileno(stdin), &c, 1); } /* Convert command (char*) into cmd (char**, one word per string) */ for (tmpCmd=command, i=0; (tmpCmd=strsep(&command, " \t")) != NULL;) { if (*tmpCmd != '\0') { cmd[i] = tmpCmd; tmpCmd++; i++; } } cmd[i] = NULL; /* Log the process name and args */ message(LOG, "Starting pid %d, console %s: '%s'\r\n", shell_pgid, terminal, cmd[0]); /* Now run it. The new program will take over this PID, * so nothing further in init.c should be run. */ execvp(cmd[0], cmd); /* We're still here? Some error happened. */ message(LOG|CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0], strerror(errno)); exit(-1); } return pid; } /* Make sure there is enough memory to do something useful. * * Calls swapon if needed so be sure /proc is mounted. */ static void check_memory() { struct stat statbuf; if (mem_total() > 3500) return; if (stat("/etc/fstab", &statbuf) == 0) { /* Try to turn on swap */ waitfor(run("/bin/swapon swapon -a", log, FALSE)); if (mem_total() < 3500) goto goodnight; } else goto goodnight; return; goodnight: message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n"); while (1) sleep(1); } #ifndef DEBUG_INIT static void shutdown_system(void) { /* Allow Ctrl-Alt-Del to reboot system. */ reboot(RB_ENABLE_CAD); message(CONSOLE, "\r\nThe system is going down NOW !!\r\n"); sync(); /* Send signals to every process _except_ pid 1 */ message(CONSOLE, "Sending SIGHUP to all processes.\r\n"); kill(-1, SIGHUP); sleep(2); sync(); message(CONSOLE, "Sending SIGKILL to all processes.\r\n"); kill(-1, SIGKILL); sleep(1); message(CONSOLE, "Disabling swap.\r\n"); waitfor(run( "swapoff -a", console, FALSE)); message(CONSOLE, "Unmounting filesystems.\r\n"); waitfor(run( "umount -a", console, FALSE)); sync(); if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) { /* bdflush, kupdate not needed for kernels >2.2.11 */ message(CONSOLE, "Flushing buffers.\r\n"); bdflush(1, 0); sync(); } } static void halt_signal(int sig) { shutdown_system(); message(CONSOLE, "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n"); sync(); #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0) if (sig == SIGUSR2) reboot(RB_POWER_OFF); else #endif reboot(RB_HALT_SYSTEM); exit(0); } static void reboot_signal(int sig) { shutdown_system(); message(CONSOLE, "Please stand by while rebooting the system.\r\n"); sync(); reboot(RB_AUTOBOOT); exit(0); } #endif void new_initAction (const struct initActionType *a, char* process, char* cons) { initAction* newAction; /* If BusyBox detects that a serial console is in use, * then entries containing non-empty id fields will _not_ be run. */ if (second_console != NULL && *cons != '\0') return; newAction = calloc ((size_t)(1), sizeof(initAction)); if (!newAction) { fprintf(stderr, "Memory allocation failure\n"); while (1) sleep(1); } newAction->nextPtr = initActionList; initActionList = newAction; strncpy( newAction->process, process, 255); newAction->action = a->action; if (*cons != '\0') strncpy(newAction->console, cons, 255); else strncpy(newAction->console, console, 255); newAction->pid = 0; } void delete_initAction (initAction *action) { initAction *a, *b=NULL; for( a=initActionList ; a; b=a, a=a->nextPtr) { if (a == action && b != NULL) { b->nextPtr=a->nextPtr; free( a); break; } } } /* NOTE that if BB_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 BB_FEATURE_USE_INITTAB * _is_ defined, but /etc/inittab is missing == same * default behavior. * */ void parse_inittab(void) { #ifdef BB_FEATURE_USE_INITTAB FILE* file; char buf[256], buf1[256]; char *p, *q, *r, *s; const struct initActionType *a = actions; int foundIt; file = fopen(INITTAB, "r"); if (file == NULL) { /* No inittab file -- set up some default behavior */ #endif /* Askfirst shell on tty1 */ new_initAction( &(actions[3]), SHELL, console ); /* Askfirst shell on tty2 */ if (second_console != NULL) new_initAction( &(actions[3]), SHELL, second_console ); /* sysinit */ new_initAction( &(actions[0]), INIT_SCRIPT, console ); return; #ifdef BB_FEATURE_USE_INITTAB } while ( fgets(buf, 255, file) != NULL) { foundIt=FALSE; for(p = buf; *p == ' ' || *p == '\t'; p++); if (*p == '#' || *p == '\n') continue; /* Trim the trailing \n */ q = strrchr( p, '\n'); if (q != NULL) *q='\0'; /* Keep a copy around for posterity's sake (and error msgs) */ strcpy(buf1, buf); /* Grab the ID field */ s=p; p = strchr( p, ':'); if ( p != NULL || *(p+1) != '\0' ) { *p='\0'; ++p; } /* Now peal off the process field from the end * of the string */ q = strrchr( p, ':'); if ( q == NULL || *(q+1) == '\0' ) { fprintf(stderr, "Bad inittab entry: %s\n", buf1); continue; } else { *q='\0'; ++q; } /* Now peal off the action field */ r = strrchr( p, ':'); if ( r == NULL || *(r+1) == '\0') { fprintf(stderr, "Bad inittab entry: %s\n", buf1); continue; } else { ++r; } /* Ok, now process it */ a = actions; while (a->name != 0) { if (strcmp(a->name, r) == 0) { new_initAction( a, q, s); foundIt=TRUE; } a++; } if (foundIt==TRUE) continue; else { /* Choke on an unknown action */ fprintf(stderr, "Bad inittab entry: %s\n", buf1); } } return; #endif } extern int init_main(int argc, char **argv) { initAction *a; pid_t wpid; int status; #ifndef DEBUG_INIT /* Expect to be PID 1 iff we are run as init (not linuxrc) */ if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) { usage( "init\n\nInit is the parent of all processes.\n\n" "This version of init is designed to be run only by the kernel\n"); } /* from the controlling terminal */ setsid(); /* Set up sig handlers -- be sure to clear all of these in run() */ signal(SIGUSR1, halt_signal); signal(SIGUSR2, reboot_signal); signal(SIGINT, reboot_signal); signal(SIGTERM, reboot_signal); /* Turn off rebooting via CTL-ALT-DEL -- we get a * SIGINT on CAD so we can shut things down gracefully... */ reboot(RB_DISABLE_CAD); #endif /* Figure out where the default console should be */ console_init(); /* Close whatever files are open, and reset the console. */ close(0); close(1); close(2); set_term(0); /* Make sure PATH is set to something sane */ putenv(_PATH_STDPATH); /* Hello world */ #ifndef DEBUG_INIT message(CONSOLE|LOG, "init started: BusyBox v%s (%s) multi-call binary\r\n", BB_VER, BB_BT); #else message(CONSOLE|LOG, "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n", getpid(), BB_VER, BB_BT); #endif /* Mount /proc */ if (mount ("proc", "/proc", "proc", 0, 0) == 0) { message(CONSOLE|LOG, "Mounting /proc: done.\n"); kernel_version = get_kernel_revision(); } else message(CONSOLE|LOG, "Mounting /proc: failed!\n"); /* Make sure there is enough memory to do something useful. */ check_memory(); /* Check if we are supposed to be in single user mode */ if ( argc > 1 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) { /* Ask first then start a shell on tty2 */ if (second_console != NULL) new_initAction( &(actions[3]), SHELL, second_console); /* Ask first then start a shell on tty1 */ new_initAction( &(actions[3]), SHELL, console); } else { /* Not in single user mode -- see what inittab says */ /* NOTE that if BB_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(); } /* Now run everything that needs to be run */ /* First run the sysinit command */ for( a=initActionList ; a; a=a->nextPtr) { if (a->action == SYSINIT) { waitfor(run(a->process, console, FALSE)); /* Now remove the "sysinit" entry from the list */ delete_initAction( a); } } /* Next run anything that wants to block */ for( a=initActionList ; a; a=a->nextPtr) { if (a->action == WAIT) { waitfor(run(a->process, console, FALSE)); /* Now remove the "wait" entry from the list */ delete_initAction( a); } } /* Next run anything to be run only once */ for( a=initActionList ; a; a=a->nextPtr) { if (a->action == ONCE) { run(a->process, console, FALSE); /* Now remove the "once" entry from the list */ delete_initAction( a); } } /* Now run the looping stuff for the rest of forever */ while (1) { for( a=initActionList ; a; a=a->nextPtr) { /* Only run stuff with pid==0. If they have * a pid, that means they are still running */ if (a->pid == 0) { switch(a->action) { case RESPAWN: /* run the respawn stuff */ a->pid = run(a->process, console, FALSE); break; case ASKFIRST: /* run the askfirst stuff */ a->pid = run(a->process, console, TRUE); break; /* silence the compiler's incessant whining */ default: break; } } } /* Wait for a child process to exit */ wpid = wait(&status); if (wpid > 0 ) { /* Find out who died and clean up their corpse */ for( a=initActionList ; a; a=a->nextPtr) { if (a->pid==wpid) { a->pid=0; message(LOG, "Process '%s' (pid %d) exited. Scheduling it for restart.\n", a->process, wpid); } } } sleep(1); } }