#include "usg_common.h"
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#include "usg_typedef.h"
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#include <sys/file.h>
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#include <fcntl.h>
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int open_file(char *filename) {
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int fd = open(filename, O_CREAT | O_APPEND | O_RDWR , FILE_MODE);
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return fd;
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}
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void write_to_file_with_no_lock(int fd, int start, int end) {
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int i;
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char buf[1024];
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for(i = start; i< end; i++) {
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sprintf(buf, "%d\n", i);
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if (write(fd, buf, strlen(buf)) == -1) {
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err_exit(errno, "write_to_file");
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}
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}
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}
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void write_to_file_with_lock(int fd, int start, int end) {
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int i;
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char buf[1024];
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for(i = start; i< end; i++) {
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sprintf(buf, "%d\n", i);
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if (flock(fd , LOCK_EX) == -1) {
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err_exit(errno, "LOCK_EX");
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}
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if (write(fd, buf, strlen(buf)) == -1) {
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err_exit(errno, "write_to_file");
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}
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if (flock(fd, LOCK_UN) == -1)
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err_exit(errno, "LOCK_UN");
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}
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}
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void write_to_file(int fd, int start, int end) {
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write_to_file_with_no_lock(fd, start, end);
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//write_to_file_with_lock(fd, start, end);
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}
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void read_from_file(int fd) {
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lseek(fd, 0, SEEK_SET);
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char buf[1024];
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while(read( fd, buf, 1024) > 0) {
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printf("%s", buf);
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}
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}
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int main() {
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int fd = open_file("test.txt");
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int status, i = 0, processors = 4, scale = 100;
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pid_t productors[processors], consumers[processors];
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pid_t pid;
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fd = open_file("stand.txt");
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write_to_file_with_no_lock(fd, 0, processors * scale);
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read_from_file(fd);
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for ( i = 0; i < processors; i++) {
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if ((productors[i] = fork()) == 0) /* Child runs user job */
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{
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fd = open_file("test.txt");
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int start = i * scale, end = i * scale + scale;
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printf("======start=%d, end=%d\n", start, end);
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write_to_file(fd, start, end);
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sleep(1);
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exit(0);
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}
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}
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// for ( i = 0; i < processors; i++) {
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// if ((consumers[i] = fork()) == 0) /* Child runs user job */
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// {
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// // char cmd[1000];
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// // char *argv[] = {"productor", start, end, NULL };
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// const char *cmd = "./consumer >> c.txt";
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// if (execl("/bin/bash", "bash", "-c", cmd, 0) < 0)
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// {
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// err_exit(errno, "consumers execve");
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// }
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// }
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// }
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while ((pid = waitpid(-1, &status, 0)) > 0) {
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if(WIFEXITED(status)) {
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//fprintf(stderr, "child %d terminated normally with exit status=%d\n", pid, WEXITSTATUS(status));
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}else
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fprintf(stderr, "child %d terminated abnormally\n", pid);
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}
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if (errno != ECHILD)
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perror("waitpid error");
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close(fd);
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}
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