82 lines
1.3 KiB
C
82 lines
1.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/wait.h>
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int p[2];
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void sigcont() {
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signal(SIGCONT,sigcont); /* reset signal */
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printf("CHILD: Got SIGCONT\n");
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exit(0);
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}
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void sigstop() {
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signal(SIGSTOP,sigstop); /* reset signal */
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printf("CHILD: Got SIGSTOP\n");
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exit(1);
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}
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void childloop(void)
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{
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signal(SIGCONT,sigcont); /* set function calls */
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signal(SIGSTOP,sigstop); /* set function calls */
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printf("Child going to loop...\n");
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close(p[1]);
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close(p[0]);
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for(;;){
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/* loop for ever */
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printf(".");
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usleep(500);
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}
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exit(0);
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}
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int
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main() {
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int pid, child, cstatus;
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char dummy[1];
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/* get child process */
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if(pipe(p)){
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perror("pipe");
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exit(1);
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}
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if ((pid = fork()) < 0) {
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perror("fork");
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exit(2);
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}
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if (pid == 0) {
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childloop();
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}
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else /* parent */
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{
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close(p[1]);
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if(read(p[0], &dummy, 1) > 0){
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printf("sync read received data");
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exit(EXIT_FAILURE);
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}
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close(p[0]);
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sleep(2);
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printf("PARENT: sending SIGSTOP\n");
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kill(pid,SIGSTOP);
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sleep(4);
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printf("PARENT: sending SIGCONT\n");
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kill(pid,SIGCONT);
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child = wait(&cstatus);
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if(child == pid && cstatus == 0)
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exit(0);
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else
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{
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printf("PARENT: child exited with status %d\n", cstatus);
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exit(1);
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}
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}
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}
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