90 lines
1.4 KiB
C
90 lines
1.4 KiB
C
/* test 4 */
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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pid_t pid0, pid1, pid2, pid3;
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int s, i, fd, nextb;
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char *tempfile = "test4.temp";
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char buf[1024];
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#define MAX_ERROR 2
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#include "common.c"
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int main(void);
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void subr(void);
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void nofork(void);
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void quit(void);
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int main()
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{
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int k;
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start(4);
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creat(tempfile, 0777);
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for (k = 0; k < 20; k++) {
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subr();
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}
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unlink(tempfile);
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quit();
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return(-1); /* impossible */
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}
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void subr()
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{
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if ( (pid0 = fork()) != 0) {
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/* Parent 0 */
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if (pid0 < 0) nofork();
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if ( (pid1 = fork()) != 0) {
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/* Parent 1 */
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if (pid1 < 0) nofork();
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if ( (pid2 = fork()) != 0) {
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/* Parent 2 */
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if (pid2 < 0) nofork();
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if ( (pid3 = fork()) != 0) {
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/* Parent 3 */
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if (pid3 < 0) nofork();
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for (i = 0; i < 10000; i++);
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kill(pid2, 9);
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kill(pid1, 9);
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kill(pid0, 9);
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wait(&s);
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wait(&s);
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wait(&s);
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wait(&s);
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} else {
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fd = open(tempfile, O_RDONLY);
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lseek(fd, 20480L * nextb, 0);
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for (i = 0; i < 10; i++) read(fd, buf, 1024);
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nextb++;
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close(fd);
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exit(0);
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}
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} else {
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while (1) getpid();
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}
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} else {
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while (1) getpid();
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}
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} else {
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while (1) getpid();
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}
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}
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void nofork()
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{
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int e = errno;
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printf("Fork failed: %s (%d)\n",strerror(e),e);
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exit(1);
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}
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