int set_proc_mountpoint(char *path)
{
int sfd = get_service_fd(PROC_FD_OFF), fd;
close_proc();
fd = open(path, O_DIRECTORY | O_RDONLY);
if (fd == -1) {
pr_err("Can't open %s\n", path);
return -1;
}
sfd = dup2(fd, sfd);
close(fd);
if (sfd < 0) {
pr_err("Can't set proc fd");
return -1;
}
proc_dir_fd = sfd;
return 0;
}
int main(int argc, char *argv[]) {
if(argc != 2) {
fprintf(stderr, "Error: use %s with one argument.\n", argv[0]);
return 1;
}
char *endptr = NULL;
long int n = strtol(argv[1], &endptr, 10);
if((n == LONG_MAX || n == LONG_MIN) && errno == ERANGE) {
perror("strtol");
return 1;
}
if(argv[1] == endptr) {
fprintf(stderr, "Error: no digits were found.\n");
return 1;
}
if(n <= 0) {
fprintf(stderr, "Error: %ld is'n positive number.\n", n);
return 1;
}
pid_t *pids = (pid_t *)malloc(sizeof(pid_t) * n);
if(pids == NULL) {
perror("malloc");
return 1;
}
for(int i = 0; i < n; ++i)
pids[i] = -1;
key_t key = 11;
int mfd = msgget(key, IPC_CREAT | 0666);
if(mfd == -1) {
perror("msgget");
free(pids);
return 1;
}
struct msgbuf msg;
msg.mtype = 1;
msg.mtext = NULL;
if(msgsnd(mfd, &msg, 0, 0) == -1) {
perror("msgsnd");
free(pids);
msgctl(mfd, IPC_RMID, NULL);
return 1;
}
long int i;
for(i = 1; i <= n; ++i) {
pids[i - 1] = fork();
if(pids[i - 1] < 0) {
perror("fork");
msgctl(mfd, IPC_RMID, NULL);
close_proc(pids, n);
free(pids);
return 1;
} else if(pids[i - 1] == 0) {
free(pids);
struct msgbuf tmp_msg;
if(msgrcv(mfd, &tmp_msg, 0, i, 0) < 0) {
perror("msgrcv");
return 1;
}
printf("%ld ", i);
fflush(stdout);
if(i < n) {
tmp_msg.mtype = i + 1;
if(msgsnd(mfd, &tmp_msg, 0, 0) == -1) {
perror("msgsnd");
return 1;
}
}
return 0;
}
for(int j = 1; j <= i; ++j) {
int w_stat;
pid_t tmp_pid = waitpid(pids[j - 1], &w_stat, WNOHANG);
if(tmp_pid != 0) {
if(WEXITSTATUS(w_stat)) {
close_proc(pids, n);
fprintf(stderr, "Error child process.\n");
free(pids);
msgctl(mfd, IPC_RMID, NULL);
return 1;
}
}
}
}
while(1) {
int status;
pid_t pid = wait(&status);
if(!(pid > 0)) {
break;
}
if(status == 0) {
for(int i = 0; i < n; ++i) {
if (pids[i] == pid) {
pids[i] = -1;
break;
}
}
} else {
fprintf(stderr, "Error child process.\n");
close_proc(pids, n);
free(pids);
msgctl(mfd, IPC_RMID, NULL);
return 1;
break;
}
}
printf("\n");
free(pids);
msgctl(mfd, IPC_RMID, NULL);
return 0;
}
