diff options
Diffstat (limited to 'init/init.c')
| -rw-r--r-- | init/init.c | 50 |
1 files changed, 31 insertions, 19 deletions
diff --git a/init/init.c b/init/init.c index a82b45b7c..13410ac39 100644 --- a/init/init.c +++ b/init/init.c @@ -117,11 +117,13 @@ static void loop_forever(void) } /* Print a message to the specified device. - * Device may be bitwise-or'd from L_LOG | L_CONSOLE */ + * "where" may be bitwise-or'd from L_LOG | L_CONSOLE + * NB: careful, we can be called after vfork! + */ #define messageD(...) do { if (ENABLE_DEBUG_INIT) message(__VA_ARGS__); } while (0) -static void message(int device, const char *fmt, ...) +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; @@ -137,7 +139,7 @@ static void message(int device, const char *fmt, ...) if (ENABLE_FEATURE_INIT_SYSLOG) { /* Log the message to syslogd */ - if (device & L_LOG) { + if (where & L_LOG) { /* don't out "\r" */ openlog(applet_name, 0, LOG_DAEMON); syslog(LOG_INFO, "init: %s", msg + 1); @@ -157,20 +159,20 @@ static void message(int device, const char *fmt, ...) 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) return; /* don't print dup messages */ } } - if (device & L_CONSOLE) { + if (where & L_CONSOLE) { /* Send console messages to console so people will see them. */ full_write(2, msg, l); } @@ -233,7 +235,8 @@ static void console_init(void) putenv((char*)"TERM=linux"); } -/* 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; @@ -270,7 +273,8 @@ static void set_sane_term(void) tcsetattr(STDIN_FILENO, TCSANOW, &tty); } -/* Open the new terminal device */ +/* Open the new terminal device. + * NB: careful, we can be called after vfork! */ static void open_stdio_to_tty(const char* tty_name, int exit_on_failure) { /* empty tty_name means "use init's tty", else... */ @@ -286,6 +290,8 @@ static void open_stdio_to_tty(const char* tty_name, int exit_on_failure) _exit(1); if (ENABLE_DEBUG_INIT) _exit(2); + /* NB: we don't reach this if we were called after vfork. + * Thus halt_reboot_pwoff() itself need not be vfork-safe. */ halt_reboot_pwoff(SIGUSR1); /* halt the system */ } dup2(0, 1); @@ -294,22 +300,24 @@ static void open_stdio_to_tty(const char* tty_name, int exit_on_failure) set_sane_term(); } -/* wrapper around exec: - * takes string (max COMMAND_SIZE chars) - * runs [-]/bin/sh -c "exec ......." if '>' etc detected. - * otherwise splits words on whitespace and deals with leading dash. +/* 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] == '-'); + int dash = (command[0] == '-' /* maybe? && command[1] == '/' */); /* See if any special /bin/sh requiring characters are present */ if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) { strcpy(buf, "exec "); strcpy(buf + 5, command + dash); /* excluding "-" */ - /* LIBBB_DEFAULT_LOGIN_SHELL has leading dash */ + /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */ cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash); cmd[1] = (char*)"-c"; cmd[2] = buf; @@ -351,7 +359,7 @@ static pid_t run(const struct init_action *a) sigemptyset(&nmask); sigaddset(&nmask, SIGCHLD); sigprocmask(SIG_BLOCK, &nmask, &omask); - pid = fork(); + pid = vfork(); sigprocmask(SIG_SETMASK, &omask, NULL); if (pid < 0) @@ -379,8 +387,9 @@ static pid_t run(const struct init_action *a) setsid(); /* Open the new terminal device */ - open_stdio_to_tty(a->terminal, 1 /* - exit if open fails*/); + open_stdio_to_tty(a->terminal, 1 /* - exit if open fails */); +// NB: do not enable unless you change vfork to fork above #ifdef BUT_RUN_ACTIONS_ALREADY_DOES_WAITING /* If the init Action requires us to wait, then force the * supplied terminal to be the controlling tty. */ @@ -424,7 +433,9 @@ static pid_t run(const struct init_action *a) /* Child - fall though to actually execute things */ } #endif - if (a->action_type & ASKFIRST) { + + /* NB: on NOMMU we can't wait for input in child */ + if (BB_MMU && (a->action_type & ASKFIRST)) { static const char press_enter[] ALIGN1 = #ifdef CUSTOMIZED_BANNER #include CUSTOMIZED_BANNER @@ -809,7 +820,8 @@ static void reload_signal(int sig ATTRIBUTE_UNUSED) } } #if CONFIG_FEATURE_KILL_DELAY - if (fork() == 0) { /* child */ + /* 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) { pid_t pid = a->pid; |