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nagios-plugins  1.4.16
Functions | Variables
child_test.c File Reference
#include <unistd.h>
#include <sys/wait.h>
#include <stdio.h>
#include <sys/types.h>
#include <signal.h>

Go to the source code of this file.

Functions

void popen_sigchld_handler (int)
int main ()

Variables

int childtermd

Function Documentation

int main ( )

Definition at line 11 of file child_test.c.

          {
 char str[1024];
 int pipefd[2];
 pid_t pid;
 int status, died;

        if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) {
                printf ("Cannot catch SIGCHLD\n");
              _exit(-1);
        }

  pipe (pipefd);
  switch(pid=fork()){
   case -1: 
           printf("can't fork\n");
            _exit(-1);
   
   case 0 : /* this is the code the child runs */
            close(1);      /* close stdout */
            /* pipefd[1] is for writing to the pipe. We want the output
             * that used to go to the standard output (file descriptor 1)
             * to be written to the pipe. The following command does this,
             * creating a new file descripter 1 (the lowest available) 
             * that writes where pipefd[1] goes. */
            dup (pipefd[1]); /* points pipefd at file descriptor */
            /* the child isn't going to read from the pipe, so
             * pipefd[0] can be closed */
            close (pipefd[0]);

           /* These are the commands to run, with success commented. dig and nslookup only problems */
            /*execl ("/bin/date","date",0);*/                  /* 100% */
           /*execl ("/bin/cat", "cat", "/etc/hosts", 0);*/     /* 100% */
           /*execl ("/usr/bin/dig", "dig", "redhat.com", 0);*/ /* 69% */
           /*execl("/bin/sleep", "sleep", "1", 0);*/           /* 100% */
            execl ("/usr/bin/nslookup","nslookup","redhat.com",0); /* 90% (after 100 tests), 40% (after 10 tests) */
            /*execl ("/bin/ping","ping","-c","1","localhost",0);*/    /* 100% */
            /*execl ("/bin/ping","ping","-c","1","192.168.10.32",0);*/       /* 100% */
           _exit(0);

   default: /* this is the code the parent runs */

            close(0); /* close stdin */
            /* Set file descriptor 0 (stdin) to read from the pipe */
            dup (pipefd[0]);
            /* the parent isn't going to write to the pipe */
            close (pipefd[1]);
            /* Now read from the pipe */
            fgets(str, 1023, stdin);
            /*printf("1st line output is %s\n", str);*/

           /*while (!childtermd);*/  /* Uncomment this line to fix */

            died= wait(&status);
           /*printf("died=%d status=%d\n", died, status);*/
           if (died > 0) _exit(0);
           else          _exit(1);
   }
}

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void popen_sigchld_handler ( int  signo)

Definition at line 71 of file child_test.c.

{
        if (signo == SIGCHLD) {
                /*printf("Caught sigchld\n");*/
                childtermd = 1;
        }
}

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Variable Documentation

Definition at line 9 of file child_test.c.