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

Browse Source 
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>
This commit is contained in:
Joachim Nilsson
2012-09-17 10:41:18 +02:00
parent 4657d9713a
commit b0aec188bc
5 changed files with 222 additions and 130 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Makefile
+1 -1
View File
@@ -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
+16 -115
View File
@@ -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)));
static void sig_init(void);
static int debug = 0;
static char sdown[CMD_SIZE] = "";
int debug = 0;
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
+19 -12
View File
@@ -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
+2 -2
View File
@@ -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
+184
View File
@@ -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:
*/