int main(void)
{
pid_t p;
int status;
fprintf(stderr, "Parent, PID = %ld: Creating child...\n",
(long)getpid());
p = fork();
if (p < 0) {
/* fork failed */
perror("fork");
exit(1);
}
if (p == 0) {
/* In child process */
change_pname("child");
sleep(SLEEP_SEC);
exit(101);
}
change_pname("father");
/*
* In parent process. Wait for the child to terminate
* and report its termination status.
*/
printf("Parent, PID = %ld: Created child with PID = %ld, waiting for it to terminate...\n",
(long)getpid(), (long)p);
p = wait(&status);
explain_wait_status(p, status);
printf("Parent: All done, exiting...\n");
return 0;
}
pid_t make_proc_tree(struct tree_node *node)
{
int status,i;
pid_t pid;
pid = fork();
if (pid<0){ /*Error*/
printf("%s :",node->name);
perror("fork");
exit(-1);
}
if (pid==0){
change_pname(node->name); /*Change the process name*/
printf("%s : Created \n", node->name); /*Message "created"*/
for (i=0; i<node->nr_children; i++)
make_proc_tree(node->children+i); /*recursion to create children*/
if (node->nr_children==0){ /*if leaf sleep*/
printf("%s: Sleeping...\n", node->name);
sleep(SLEEP_PROC_SEC);
printf("%s: Exiting...\n", node->name);
exit(0);
}
else {
printf("%s: Waiting...\n", node->name); /*else procedure is father of other procedures*/
for(i=0; i<node->nr_children; i++){
pid = wait(&status); /*Waiting for children to be terminated*/
explain_wait_status(pid, status);
}
printf("%s: Exiting...\n", node->name);
exit(0);
}
}
return pid;
}
//--FUNCTIONS--
void create_ptree(node_type *cur, size_t lvl) {
int status;
pid_t *CHILDREN=NULL; //Children PID array.
if (cur->nr_children>0) { //Allocation of children PID array memory.
CHILDREN=(pid_t *)malloc((cur->nr_children)*sizeof(pid_t));
if (CHILDREN==NULL) {
alloc_err;
exit(EXIT_FAILURE);
}
}
pid_t par=getpid(), child=0, retv=0;
change_pname(cur->name); //Change name.
// proc_enter(par); //Enter message.
size_t i=0;
for (i=0; i<cur->nr_children; i++) { //Create heirs.
// fprintf(stderr, "FORK LV: %u - IT: %u\n", lvl, i); //DEBUG
child=fork();
if (child<0) { //Sanity.
fork_err(cur);
exit(EXIT_FAILURE);
}
if (child==0) { //Recursion for child:
create_ptree(&cur->children[i], lvl+1);
//...
} else { //Rest of parent:
CHILDREN[i]=child;
continue;
}
}
if (cur->nr_children>0) { //Node: //Wait for heirs to sleep.
wait_for_ready_children(cur->nr_children);
} //else //Leaf: Fall-through.
if (raise(SIGSTOP)) { //Sleep yourself.
sign_err(par, "0");
exit(EXIT_FAILURE);
}
actual_msg(par, cur->name); //Wake-up and print awake message.
// fprintf(stderr, "i=%u, child=%ld, CHILDREN[i]=%ld\n", i, (long)child, (long)CHILDREN[i]);
if (cur->nr_children>0) {
for (i=0; i<cur->nr_children; i++) {//Parents continue and bury their children 1 by 1.
cont_msg(cur->name, CHILDREN[i]);
if ((kill(CHILDREN[i], SIGCONT))==-1) {
sign_err(par, "1");
exit(EXIT_FAILURE);
}
// wait_for_ready_children(1); //NEEDs DEBUGGING: Doesn't work with this instead of the 2 next commands.
retv=wait(&status); //Wait the just awoken child to terminate before you wake up the next (condition for the depth first traversal).
bury_msg(cur->name, retv); //Bury message.
}
} //else //Fall-through.
// proc_exit(par); //Exit message.
// kill(par, SIGKILL);
exit(EXIT_SUCCESS); //Children and parents who buried theirs, just roll off and die.
}
void fork_procs(struct tree_node *root)
{
pid_t child ;
int i,status ;
pid_t* children;
children = (pid_t*)malloc((sizeof(pid_t)*root->nr_children));
if (children == NULL){
fprintf(stderr, "allocate children failed\n");
exit(1);
}
printf("PID = %ld, name %s, starting...\n",(long)getpid(), root->name);
change_pname(root->name);
for (i = 0 ; i < root->nr_children; i++){
printf("%s:Creating child %s...\n",root->name,root->children[i].name);
child = fork();
if (child < 0) {
perror("child fork");
exit(1);
}
if (child == 0) {
/* Child */
fork_procs(&root->children[i]);
}
/* Father saves child's pid ! */
children[i] = child;
}
wait_for_ready_children(root->nr_children);
printf("%s: All children ready ! Suspending with SIGSTOP...\n",root->name);
/*
* Suspend Self
*/
raise(SIGSTOP);
printf("PID = %ld, name = %s is awake\n",(long)getpid(), root->name);
for (i = 0 ; i < root->nr_children;i++){
printf("%s: Activating child %s...\n",root->name,root->children[i].name);
kill(children[i],SIGCONT);
children[i] = wait(&status);
explain_wait_status(children[i],status);
}
printf("%s: Exiting...\n",root->name);
free(children);
exit(0);
}
void fork_procs(struct tree_node *current){
pid_t p_new[20];
int status;
int i;
struct tree_node *temp;
change_pname(current->name);
printf("%s:Starting..\n",current->name);
for(i=0;i<current->nr_children;i++){
p_new[i]=fork();
if(p_new[i]<0){
perror("fork");
exit(2);
}
else if(p_new[i]==0){
fork_procs(current->children+i);
}
}
wait_for_ready_children(current->nr_children);
printf("%s:I gave birth to %d childs and then suspended myself..\n",current->name,current->nr_children);
raise(SIGSTOP);
printf("%s:Before you know,awake!..\n",current->name);
for(i=0;i<current->nr_children;i++){
temp=current->children+i;
printf("I, %s , am your father %s,and i say wake!\n",current->name,temp->name);
kill(p_new[i],SIGCONT);
p_new[i]=wait(&status);
explain_wait_status(p_new[i],status);
}
printf("%s:Exiting..\n",current->name);
exit(3);
}
