72 lines
1.1 KiB
C
72 lines
1.1 KiB
C
/* allow_oversubscribe.c COPYRIGHT FUJITSU LIMITED 2018 */
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#include <stdio.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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#include <stdlib.h>
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#define PROG "/usr/bin/date"
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static int
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do_fork(int proc_num)
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{
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int i;
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for (i = 0; i < proc_num; i += 1) {
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pid_t pid = fork();
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if (pid < 0) {
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perror("fork failed");
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return -1;
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}
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else if (0 == pid) {
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printf("%d: in child (%d/%d)\n",
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getpid(), (i+1), proc_num);
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execl(PROG, PROG, NULL);
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exit(0);
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/* NOTREACHED */
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}
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}
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return 0;
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}
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static int
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do_wait(int proc_num)
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{
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pid_t mypid = getpid();
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int i;
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printf("%d: in parent\n", mypid);
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for (i = 0; i < proc_num; i += 1) {
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int status;
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pid_t pid = waitpid(-1, &status, 0);
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if (pid < 0) {
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perror("waitpid failed");
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return -1;
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}
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printf("%d: waited %d (%d/%d)\n",
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mypid, pid, (i+1), proc_num);
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}
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printf("%d: all done\n", mypid);
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return 0;
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}
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int
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main(int argc, char *argv[])
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{
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int result = 0;
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int proc_num = atoi(argv[1]);
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if (do_fork(proc_num)) {
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result = -1;
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}
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if (do_wait(proc_num)) {
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result = -1;
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}
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return result;
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}
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