kaguya
50 lines
742 B
C
50 lines
742 B
C
#include <assert.h>
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#include <signal.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <sys/wait.h>
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static void noop(int x) {
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(void)x;
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}
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int main() {
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signal(SIGUSR1, &noop);
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int pid;
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switch(pid = fork()) {
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case -1:
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perror("fork");
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abort();
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case 0:
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pause();
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assert(errno == EINTR);
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return 0;
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default:
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while (1) {
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usleep(100);
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kill(pid, SIGUSR1);
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usleep(100);
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int status;
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errno = 0;
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if (waitpid(-1, &status, WNOHANG) <= 0) {
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if (errno && errno != EAGAIN) {
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perror("wait");
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kill(pid, SIGKILL);
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}
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continue;
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}
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if (!WIFEXITED(status)) {
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printf("wait returned %x\n", status);
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abort();
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}
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return WEXITSTATUS(status);
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}
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}
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}
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