50 lines
726 B
C
50 lines
726 B
C
#include <sys/stat.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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const char default_path[] = "hello.txt";
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int
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main(int argc, char *argv[])
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{
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char buf[2] = {0x41, 0x0a};
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char *pathname = (char *)default_path;
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int fd = -1;
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if (argc > 1) {
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pathname = argv[1];
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}
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fd = open(pathname, O_WRONLY|O_CREAT, S_IWUSR|S_IRUSR);
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if (fd == -1) {
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perror("open");
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exit(1);
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}
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pid_t pid = fork();
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if (pid < 0) {
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perror("fork");
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exit(1);
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}
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else if (pid > 0) {
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for (int i = 0; i < 5; i++) {
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write(fd, buf, 2);
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sleep(1);
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}
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}
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else {
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buf[0] = 0x42;
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for (int i = 0; i < 5; i++) {
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write(fd, buf, 2);
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sleep(1);
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}
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}
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close(fd);
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exit(0);
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}
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