minix/servers/sm/manager.c
2005-07-26 13:08:57 +00:00

86 lines
2.5 KiB
C

/* This file contains procedures to manage the system processes.
*
* The entry points into this file are
* do_start:
* do_stop:
* do_exit: a child of this server exited
*
* Changes:
* Jul 22, 2005: Created (Jorrit N. Herder)
*/
#include "sm.h"
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
extern int errno;
#define EXEC_FAILED 49 /* recognizable exit status */
/*===========================================================================*
* do_start *
*===========================================================================*/
PUBLIC int do_start(message *m_ptr)
{
pid_t child_pid;
char command[255] = "/usr/sbin/is";
/* Obtain command name and parameters. */
/* Now try to execute the new system service. */
child_pid = fork(); /* normal POSIX fork */
switch(child_pid) {
case 0: /* child process, start system service */
execve(command, NULL, NULL); /* POSIX exec */
report("SM", "warning, exec() failed", errno); /* shouldn't happen */
exit(EXEC_FAILED); /* terminate child */
break;
case -1: /* fork failed, report error */
report("SM", "warning, fork() failed", errno); /* shouldn't happen */
return(errno);
default: /* parent process */
report("SM", "new process forked, pid", child_pid);
/* update tables */
}
return(OK);
}
/*===========================================================================*
* do_stop *
*===========================================================================*/
PUBLIC int do_stop(message *m_ptr)
{
return(ENOSYS);
}
/*===========================================================================*
* do_exit *
*===========================================================================*/
PUBLIC int do_exit(message *m_ptr)
{
pid_t exit_pid;
int exit_status;
printf("SM: got SIGCHLD signal, doing wait to get exited child.\n");
/* See which child exited and what the exit status is. This is done in a
* loop because multiple childs may have exited, all reported by one
* SIGCHLD signal. The WNOHANG options is used to prevent blocking if,
* somehow, no exited child can be found.
*/
while ( (exit_pid = waitpid(-1, &exit_status, WNOHANG)) != 0 ) {
printf("SM: pid %d,", exit_pid);
if (WIFSIGNALED(exit_status)) {
printf("killed, signal number %d\n", WTERMSIG(exit_status));
} else if (WIFEXITED(exit_status)) {
printf("normal exit, status %d\n", WEXITSTATUS(exit_status));
}
}
return(OK);
}