On Thursday 04 September 2008 08:08, Vladimir Dronnikov wrote:
> >
> > and stage 3 is not needed at all - "killall5 -TERM" etc still works,
> > no need to talk to init.
> >
>
> I see. But IMO killall5ing would just makes kernel panic after /sbin/init
> exits, right?
No. Even killall5 -KILL won't. Process with PID 1 is not killed,
even if it is a shell. Kernel will not panic.
Also, killall5 does not kill processes in its session,
so it works just fine to have killall5 in a shutdown shell script.
I mean, killall5 doesn't kill its own parent process (shell) too.
> How to reboot?
hardshutdown -r
See attached.
--
vda
/* Including <unistd.h> makes sure that on a glibc system
<features.h> is included, which again defines __GLIBC__ */
#include <unistd.h>
#include <stdio.h> /* puts */
#include <time.h> /* nanosleep */
#include <errno.h>
#include "linux_reboot.h" /* reboot magic */
#define USE_LIBC
#ifdef USE_LIBC
/* libc version */
#if defined __GLIBC__ && __GLIBC__ >= 2
# include <sys/reboot.h>
# define REBOOT(cmd) reboot(cmd)
#else
extern int reboot(int, int, int);
# define REBOOT(cmd) reboot(LINUX_REBOOT_MAGIC1,LINUX_REBOOT_MAGIC2,(cmd))
#endif
int my_reboot(int cmd) {
return REBOOT(cmd);
}
#else /* no USE_LIBC */
/* direct syscall version */
#include <linux/unistd.h>
#ifdef _syscall3
_syscall3(int, reboot, int, magic, int, magic_too, int, cmd);
#else
/* Let us hope we have a 3-argument reboot here */
extern int reboot(int, int, int);
#endif
int my_reboot(int cmd) {
return reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd);
}
#endif
void do_reboot() {
my_reboot(LINUX_REBOOT_CMD_RESTART);
}
void do_poweroff() {
my_reboot(LINUX_REBOOT_CMD_POWER_OFF);
}
void do_halt() {
my_reboot(LINUX_REBOOT_CMD_HALT);
}
void usage() {
puts(
"Usage: hardshutdown -h|-r|-p [NN]\n"
" NN - seconds to sleep before requested action"
);
exit(1);
}
enum action_t {
SHUTDOWN, // do nothing
HALT,
POWEROFF,
REBOOT
};
int main(int argc, char *argv[]) {
struct timespec t = {0,0};
enum action_t action = SHUTDOWN;
int c, i;
char *prog, *ptr;
//if(*argv[0] == '-') argv[0]++; /* allow shutdown as login shell */
prog = argv[0];
if( (ptr=strrchr(prog,'/')) != 0 ) prog = ptr+1;
for(c=1; c < argc; c++) {
if(argv[c][0] >= '0' && argv[c][0] <= '9') {
t.tv_sec = strtol(argv[c], NULL, 10);
continue;
}
if(argv[c][0] != '-') {
usage();
return 1;
}
for(i=1; argv[c][i]; i++) {
switch(argv[c][i]) {
case 'h':
action = HALT;
break;
case 'p':
action = POWEROFF;
break;
case 'r':
action = REBOOT;
break;
default:
usage();
return 1;
}
}
}
if(action==SHUTDOWN) {
usage();
return 1;
}
chdir("/");
while(nanosleep(&t,&t)<0)
if(errno!=EINTR) break;
switch(action) {
case HALT:
do_halt(); break;
case POWEROFF:
do_poweroff(); break;
case REBOOT:
do_reboot(); break;
}
return 1;
}
/*
* Magic values required to use _reboot() system call.
*/
#define LINUX_REBOOT_MAGIC1 0xfee1dead
#define LINUX_REBOOT_MAGIC2 672274793
#define LINUX_REBOOT_MAGIC2A 85072278
#define LINUX_REBOOT_MAGIC2B 369367448
/*
* Commands accepted by the _reboot() system call.
*
* RESTART Restart system using default command and mode.
* HALT Stop OS and give system control to ROM monitor, if any.
* CAD_ON Ctrl-Alt-Del sequence causes RESTART command.
* CAD_OFF Ctrl-Alt-Del sequence sends SIGINT to init task.
* POWER_OFF Stop OS and remove all power from system, if possible.
* RESTART2 Restart system using given command string.
*/
#define LINUX_REBOOT_CMD_RESTART 0x01234567
#define LINUX_REBOOT_CMD_HALT 0xCDEF0123
#define LINUX_REBOOT_CMD_CAD_ON 0x89ABCDEF
#define LINUX_REBOOT_CMD_CAD_OFF 0x00000000
#define LINUX_REBOOT_CMD_POWER_OFF 0x4321FEDC
#define LINUX_REBOOT_CMD_RESTART2 0xA1B2C3D4
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