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