Further cleanup, move signal setup to a file of its own.

finit.c:
        o Perform signal setup as soon as possible, no need to do any
          mounting of /proc or /sys beforehand
        o Move signal setup and callbacks to a file of its own
        o Use more #defines for hard coded strings
        o Use a more neutral default hostname

signal.c:
        o New file, for setup and signal handlers
        o Add support for SIGSTOP/SIGSTP and SIGCONT.  This pauses finit
          respawning of xinit/shell.  Useful for, e.g., debugging
        o Document each ignored and handled signal better
        o Disable SIGUSR1 and SIGUSR2 for now, will be reenabled later

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Makefile

@@ -28,7 +28,7 @@ ROOTDIR    ?= $(shell pwd)
 VERSION     = 1.0-pre
 PKG	    = finit-$(VERSION)
 EXEC        = finit
-OBJS        = finit.o helpers.o initctl.o
+OBJS        = finit.o helpers.o initctl.o signal.o
 SRCS        = $(OBJS:.o=.c)
 DEPS        = $(addprefix .,$(SRCS:.c=.d))
 CPPFLAGS   += -DVERSION=\"$(VERSION)\" -DWHOAMI=\"`whoami`@`hostname`\"

finit.c

@@ -22,31 +22,18 @@
   THE SOFTWARE.
 */
 
-#include <stdio.h>
 #include <string.h>
-#include <stdlib.h>
 #include <ctype.h>
 #include <sys/mount.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
 #include <dirent.h>
-#include <errno.h>
-#include <signal.h>
-#include <unistd.h>
-#include <sys/reboot.h>
-#include <sys/wait.h>
 #include <linux/fs.h>
 #include <utmp.h>
 
 #include "finit.h"
 #include "helpers.h"
 
-static void chld_handler(int sig __attribute__ ((unused)));
+int debug = 0;
-static void sig_init(void);
+char sdown[CMD_SIZE] = "";
-
-static int debug = 0;
-static char sdown[CMD_SIZE] = "";
 
 
 static void build_cmd(char *cmd, char *x, int len)
@@ -57,7 +44,7 @@ static void build_cmd(char *cmd, char *x, int len)
 	c = cmd + strlen(cmd);
 
 	/* skip spaces */
-	for (; *x && (*x == ' ' || *x == '\t'); x++) ;
+	for (; *x && (*x == ' ' || *x == '\t'); x++);
 
 	/* copy next arg */
 	for (l = 0; *x && *x != '#' && *x != '\t' && l < len; l++)
@@ -72,7 +59,7 @@ int main(void)
 	FILE *f;
 	char line[LINE_SIZE];
 	char username[USERNAME_SIZE] = DEFUSER;
-	char hostname[HOSTNAME_SIZE] = "eviltwin";
+	char hostname[HOSTNAME_SIZE] = DEFHOST;
 	char cmd[CMD_SIZE];
 	char startx[CMD_SIZE] = "xinit";
 #ifdef USE_ETC_RESOLVCONF_RUN
@@ -86,15 +73,15 @@ int main(void)
 	int fd;
 #endif
 
+	/* Setup signals */
+	sig_init();
+
 	chdir("/");
 	umask(022);
 
 	mount("none", "/proc", "proc", 0, NULL);
 	mount("none", "/sys", "sysfs", 0, NULL);
 
-	/* Setup signals */
-	sig_init();
-
 	/*
 	 * Parse kernel parameters
 	 */
@@ -119,7 +106,8 @@ int main(void)
 	if ((f = fopen("/etc/finit.conf", "r")) != NULL) {
 		char *x;
 		while (!feof(f)) {
-			fgets(line, LINE_SIZE, f);
+			if (!fgets(line, LINE_SIZE, f))
+				continue;
 			chomp(line);
 
 			_d("conf: %s", line);
@@ -308,6 +296,7 @@ int main(void)
 	touch("/etc/network/run/ifstate");
 #endif
 
+	/* Set initial hostname. */
 	if ((f = fopen("/etc/hostname", "r")) != NULL) {
 		fgets(hostname, HOSTNAME_SIZE, f);
 		chomp(hostname);
@@ -401,7 +390,12 @@ int main(void)
 		/* ConsoleKit needs this */
 		setenv("DISPLAY", ":0", 1);
 
-		while (!fexist("/tmp/shutdown")) {
+		while (!fexist(SYNC_SHUTDOWN)) {
+			if (fexist(SYNC_STOPPED)) {
+				sleep(2);
+				continue;
+			}
+
 			_d("start X as %s\n", username);
 			if (debug) {
 				snprintf(line, LINE_SIZE,
@@ -434,99 +428,6 @@ int main(void)
 	return 0;
 }
 
-/*
- * Shut down on INT USR1 USR2
- */
-void shutdown_handler(int sig)
-{
-	touch("/tmp/shutdown");
-	if (sdown[0] != 0) {
-		system(sdown);
-	}
-
-	kill(-1, SIGTERM);
-
-	write(1, "\033[?25l\033[30;40m", 14);
-	copyfile("/boot/shutdown.fb", "/dev/fb/0", 0);
-	sleep(2);
-
-	system("/usr/sbin/alsactl store > /dev/null 2>&1");
-	system("/sbin/hwclock --systohc");
-
-	kill(-1, SIGKILL);
-
-	sync();
-	sync();
-	system("/bin/umount -a;/bin/mount -n -o remount,ro /");
-	//system("/sbin/unionctl.static / --remove / > /dev/null 2>&1");
-
-	if (sig == SIGINT || sig == SIGUSR1)
-		reboot(RB_AUTOBOOT);
-
-	reboot(RB_POWER_OFF);
-}
-
-/*
- * SIGCHLD: one of our children has died
- */
-static void chld_handler(int sig __attribute__ ((unused)))
-{
-	int status;
-
-	while (waitpid(-1, &status, WNOHANG) != 0) {
-		if (errno == ECHILD)
-			break;
-	}
-}
-
-/*
- * Signal management - Be conservative with what finit responds to!
- *
- * The standard SysV init only responds to the following signals:
- *	 SIGHUP
- *	      Has the same effect as telinit q.
- *
- *	 SIGUSR1
- *	      On receipt of this signals, init closes and re-opens  its	 control
- *	      fifo, /dev/initctl. Useful for bootscripts when /dev is remounted.
- *
- *	 SIGINT
- *	      Normally the kernel sends this signal to init when CTRL-ALT-DEL is
- *	      pressed. It activates the ctrlaltdel action.
- *
- *	 SIGWINCH
- *	      The kernel sends this signal when the KeyboardSignal key	is  hit.
- *	      It activates the kbrequest action.
- */
-static void sig_init(void)
-{
-	int i;
-	sigset_t nmask;
-	struct sigaction sa;
-
-	for (i = 1; i < NSIG; i++)
-		SETSIG(sa, i, SIG_IGN, SA_RESTART);
-
-	SETSIG(sa, SIGINT, shutdown_handler, 0);
-	SETSIG(sa, SIGPWR, SIG_IGN, 0);
-	SETSIG(sa, SIGUSR1, shutdown_handler, 0);
-	SETSIG(sa, SIGUSR2, shutdown_handler, 0);
-	SETSIG(sa, SIGTERM, SIG_IGN, 0);
-	SETSIG(sa, SIGALRM, SIG_IGN, 0);
-	SETSIG(sa, SIGHUP, SIG_IGN, 0);
-	SETSIG(sa, SIGCONT, SIG_IGN, SA_RESTART);
-	SETSIG(sa, SIGCHLD, chld_handler, SA_RESTART);
-
-	/* Block sigchild while forking */
-	sigemptyset(&nmask);
-	sigaddset(&nmask, SIGCHLD);
-	sigprocmask(SIG_BLOCK, &nmask, NULL);
-
-	/* Disable CTRL-ALT-DELETE from kernel, we handle shutdown gracefully with SIGINT */
-	reboot(RB_DISABLE_CAD);
-	setsid();
-}
-
 /**
  * Local Variables:
  *  version-control: t

finit.h

@@ -25,6 +25,15 @@
 #ifndef FINIT_H__
 #define FINIT_H__
 
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
 #include <syslog.h>
 #define DO_LOG(level, fmt, args...)				\
 {								\
@@ -71,26 +80,21 @@
 #define USE_ETC_RESOLVCONF_RUN
 #endif
 
+#define SYNC_SHUTDOWN   "/var/lock/finit.shutdown"
+#define SYNC_STOPPED    "/var/lock/finit.stopped"
+
 #ifndef DEFUSER
 #define DEFUSER "user"
 #endif
+#ifndef DEFHOST
+#define DEFHOST "noname"
+#endif
 
 #define LINE_SIZE 1024
 #define CMD_SIZE 256
 #define USERNAME_SIZE 16
 #define HOSTNAME_SIZE 32
 
-/* From sysvinit */
-/* Set a signal handler. */
-#define SETSIG(sa, sig, fun, flags)		\
-	do {					\
-		sa.sa_handler = fun;		\
-		sa.sa_flags = flags;		\
-		sigemptyset(&sa.sa_mask);	\
-		sigaction(sig, &sa, NULL);	\
-	} while (0)
-
-
 #ifndef touch
 #define touch(x) mknod((x), S_IFREG|0644, 0)
 #endif
@@ -110,7 +114,10 @@
 
 #define _d(fmt, args...) do { if (debug) { fprintf(stderr, "%s(): " fmt "\n", __func__, ##args); } } while (0)
 
-void shutdown_handler(int sig);
+extern int debug;
+
+void do_shutdown(int sig);
+void sig_init(void);
 void listen_initctl(void);
 
 #endif /* FINIT_H__ */

initctl.c

@@ -72,10 +72,10 @@ void listen_initctl(void)
 			if (request.cmd == INIT_CMD_RUNLVL) {
 				switch (request.runlevel) {
 				case '0':
-					shutdown_handler(SIGUSR2);
+					do_shutdown(SIGUSR2);
 					break;
 				case '6':
-					shutdown_handler(SIGUSR1);
+					do_shutdown(SIGUSR1);
 				}
 			}
 		}

signal.c

@@ -0,0 +1,184 @@
+/*
+  Improved fast init
+
+  Copyright (c) 2008 Claudio Matsuoka
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#include <signal.h>
+#include <sys/reboot.h>
+
+#include "finit.h"
+#include "helpers.h"
+
+#define SETSIG(sa, sig, fun, flags)			\
+	do {						\
+		sa.sa_sigaction = fun;			\
+		sa.sa_flags = SA_SIGINFO | flags;	\
+		sigemptyset(&sa.sa_mask);		\
+		sigaction(sig, &sa, NULL);		\
+	} while (0)
+
+#define IGNSIG(sa, sig, flags)			\
+	do {					\
+		sa.sa_handler = SIG_IGN;	\
+		sa.sa_flags = flags;		\
+		sigemptyset(&sa.sa_mask);	\
+		sigaction(sig, &sa, NULL);	\
+	} while (0)
+
+static int stopped = 0;
+extern char *sdown;
+
+void do_shutdown (int sig)
+{
+	touch(SYNC_SHUTDOWN);
+	if (sdown[0] != 0) {
+		system(sdown);
+	}
+
+	kill(-1, SIGTERM);
+
+	write(1, "\033[?25l\033[30;40m", 14);
+	copyfile("/boot/shutdown.fb", "/dev/fb/0", 0);
+	sleep(2);
+
+	system("/usr/sbin/alsactl store > /dev/null 2>&1");
+	system("/sbin/hwclock --systohc");
+
+	kill(-1, SIGKILL);
+
+	sync();
+	sync();
+	system("/bin/umount -a;/bin/mount -n -o remount,ro /");
+	//system("/sbin/unionctl.static / --remove / > /dev/null 2>&1");
+
+	if (sig == SIGINT || sig == SIGUSR1)
+		reboot(RB_AUTOBOOT);
+
+	reboot(RB_POWER_OFF);
+}
+
+/*
+ * Shut down on INT USR1 USR2
+ */
+static void shutdown_handler(int sig, siginfo_t *info, void *ctx __attribute__ ((unused)))
+{
+	_d("finit: Rebooting on signal %d from pid %d with code %d", sig, info->si_pid, info->si_code);
+
+	do_shutdown(sig);
+}
+
+/*
+ * SIGCHLD: one of our children has died
+ */
+static void chld_handler(int sig, siginfo_t *info, void *ctx __attribute__ ((unused)))
+{
+	int status;
+
+	_d("finit: Child died, harvesting... signal %d from pid %d with code %d", sig, info->si_pid, info->si_code);
+	while (waitpid(-1, &status, WNOHANG) != 0) {
+		if (errno == ECHILD)
+			break;
+	}
+}
+
+/*
+ * SIGSTOP: Paused by user or netflash
+ */
+static void sigstop_handler(int sig, siginfo_t *info, void *ctx __attribute__ ((unused)))
+{
+	_d("finit: Received SIGSTOP(%d) from pid %d with code %d", sig, info->si_pid, info->si_code);
+	touch(SYNC_STOPPED);
+	stopped ++;
+}
+static void sigcont_handler(int sig, siginfo_t *info, void *ctx __attribute__ ((unused)))
+{
+	_d("finit: Received SIGCONT(%d) from pid %d with code %d", sig, info->si_pid, info->si_code);
+	stopped = 0;
+	remove(SYNC_STOPPED);
+}
+
+/*
+ * Signal management - Be conservative with what finit responds to!
+ *
+ * The standard SysV init only responds to the following signals:
+ *	 SIGHUP
+ *	      Has the same effect as telinit q.
+ *
+ *	 SIGUSR1
+ *	      On receipt of this signals, init closes and re-opens  its	 control
+ *	      fifo, /dev/initctl. Useful for bootscripts when /dev is remounted.
+ *
+ *	 SIGINT
+ *	      Normally the kernel sends this signal to init when CTRL-ALT-DEL is
+ *	      pressed. It activates the ctrlaltdel action.
+ *
+ *	 SIGWINCH
+ *	      The kernel sends this signal when the KeyboardSignal key	is  hit.
+ *	      It activates the kbrequest action.
+ */
+void sig_init(void)
+{
+	int i;
+	sigset_t nmask;
+	struct sigaction sa;
+
+	for (i = 1; i < NSIG; i++)
+		IGNSIG(sa, i, SA_RESTART);
+
+	SETSIG(sa, SIGINT,  shutdown_handler, 0); /* Standard SysV init calls ctrl-alt-delete handler */
+	SETSIG(sa, SIGPWR,  shutdown_handler, 0);
+
+	/* Ignore SIGUSR1/2 for now, only BusyBox init implements them as reboot+halt. */
+//	  SETSIG2(sa, SIGUSR1, reopen_initctl, 0);
+//	  SETSIG2(sa, SIGUSR2, pwrdwn_handler, 0);
+
+	/* Init must ignore SIGTERM. May otherwise get false SIGTERM in forked children! */
+	IGNSIG(sa, SIGTERM, 0);
+
+	/* Some C APIs may need SIGALRM for implementing timers. */
+	IGNSIG(sa, SIGALRM, 0);
+
+	/* We don't have any /etc/inittab yet, reread finit.conf? */
+	IGNSIG(sa, SIGHUP, 0);
+
+	/* Stopping init is a bit tricky. */
+	SETSIG(sa, SIGSTOP, sigstop_handler, 0);
+	SETSIG(sa, SIGTSTP, sigstop_handler, 0);
+	SETSIG(sa, SIGCONT, sigcont_handler, 0);
+	SETSIG(sa, SIGCHLD, chld_handler, SA_RESTART);
+
+	/* Block SIGCHLD while forking */
+	sigemptyset(&nmask);
+	sigaddset(&nmask, SIGCHLD);
+	sigprocmask(SIG_BLOCK, &nmask, NULL);
+
+	/* Disable CTRL-ALT-DELETE from kernel, we handle shutdown gracefully with SIGINT */
+	reboot(RB_DISABLE_CAD);
+	setsid();
+}
+
+/**
+ * Local Variables:
+ *  version-control: t
+ *  c-file-style: "ellemtel"
+ * End:
+ */