int main (int argc, char *argv[]) {
char buf[BUFSIZE];
pid_t childpid = 0;
int fd;
int i, n;
if (argc != 4){ /* check for valid number of command-line arguments */
fprintf (stderr, "Usage: %s processes log_file atomic_file\n", argv[0]);
return 1;
}
n = atoi(argv[1]); /* create a process chain */
for (i = 1; i < n; i++)
if ( (childpid = fork()) )
break;
if (childpid == -1) {
perror("Failed to fork");
return 1;
}
/* open log file after the fork */
fd = open(argv[2], CREATE_FLAGS, CREATE_PERMS);
if (fd < 0) {
perror("Failed to open file");
return 1;
}
/* open atomic log after fork */
if (atomic_log_open(argv[3]) == -1) {
fprintf(stderr, "Failed to open log file");
return 1;
}
/* write twice to the common log file */
sprintf(buf, "i:%d process:%ld ", i, (long)getpid());
write(fd, buf, strlen(buf));
atomic_log_string(buf);
sprintf(buf, "parent:%ld child:%ld\n", (long)getppid(), (long)childpid);
write(fd, buf, strlen(buf));
atomic_log_string(buf);
/* atomic_log_printf("i:%d process:%ld parent:%ld child:%ld\n", i, (long)getpid(), (long)getppid(), (long)childpid); */
if ( atomic_log_send() == -1 ) {
fprintf(stderr, "Failed to send to log file");
return 1;
}
atomic_log_close();
return 0;
}
main(int argc, char* argv[]){
char *LogFileName; // pathname
int RandSeed = 1; // rand seed
int ChildProcessIndex = 0;
int NumberofChildProcess = 0; // number of process
int NumberofMessage = 1;
double SleepForAWhile = 0;
int fd;
if(argc != 4)
err_quit("usage: hw1 filename seed numberofprocess\n");
pid_t pid;
LogFileName = argv[1];
RandSeed = atoi(argv[2]);
NumberofChildProcess = atoi(argv[3]);
//Set the seed for random number generator
srand(RandSeed);
//At most fork NumberofPorcess childs, and only parent can fork.
while(ChildProcessIndex < NumberofChildProcess){
// At most 200 messages
NumberofMessage = (int)100 * (1.0 + (double)rand()/(RAND_MAX));
// At most sleep for 1 seconds
SleepForAWhile = (double)rand()/(RAND_MAX);
printf("Number of messages for Child Process %c = %d\n",
ChildProcessIndex + 65, NumberofMessage);
printf("sleep_time for Child Process %c = %f\n",
ChildProcessIndex + 65, SleepForAWhile);
fflush(stdout);
// Fork a child process
if ((pid=fork()) < 0)
/*Fork error*/
err_quit("fork error\n");
else if ( pid == 0){
// Child process
//
// We will ask the child process to sleep
// for a while first. Then, it will generate
// a number of log messages, store the messages
// in memory, and send the messages to the log
// file at the end.
int index = 0;
usleep(SleepForAWhile * 1000000);
if((fd = atomic_log_open( LogFileName )) == -1)
err_quit("open/create file error\n");
for (index = 0; index < NumberofMessage; index++){
char LogMessage[40];
sprintf(LogMessage, "Child Process %c: Message-ID: %d \n",
ChildProcessIndex + 65, index);
#ifdef DEBUG
fprintf(stderr, LogMessage);
#endif
if(log_string(LogMessage) < strlen(LogMessage)) {
break;
}
}
atomic_log_send(fd);
_exit(0);
}else
/*Parent Process*/
ChildProcessIndex++;
}
/*Fork successfully*/
exit(0);
}
