/* do_fork - parent process for a new child process
* @clone_flags: used to guide how to clone the child process
* @stack: the parent's user stack pointer. if stack==0, It means to fork a kernel thread.
* @tf: the trapframe info, which will be copied to child process's proc->tf
*/
int
do_fork(uint32_t clone_flags, uintptr_t stack, struct trapframe *tf) {
int ret = -E_NO_FREE_PROC;
struct proc_struct *proc;
if (nr_process >= MAX_PROCESS) {
goto fork_out;
}
ret = -E_NO_MEM;
//LAB4:EXERCISE2 2013011303
/*
* Some Useful MACROs, Functions and DEFINEs, you can use them in below implementation.
* MACROs or Functions:
* alloc_proc: create a proc struct and init fields (lab4:exercise1)
* setup_kstack: alloc pages with size KSTACKPAGE as process kernel stack
* copy_mm: process "proc" duplicate OR share process "current"'s mm according clone_flags
* if clone_flags & CLONE_VM, then "share" ; else "duplicate"
* copy_thread: setup the trapframe on the process's kernel stack top and
* setup the kernel entry point and stack of process
* hash_proc: add proc into proc hash_list
* get_pid: alloc a unique pid for process
* wakup_proc: set proc->state = PROC_RUNNABLE
* VARIABLES:
* proc_list: the process set's list
* nr_process: the number of process set
*/
// 1. call alloc_proc to allocate a proc_struct
// 2. call setup_kstack to allocate a kernel stack for child process
// 3. call copy_mm to dup OR share mm according clone_flag
// 4. call copy_thread to setup tf & context in proc_struct
// 5. insert proc_struct into hash_list && proc_list
// 6. call wakup_proc to make the new child process RUNNABLE
// 7. set ret vaule using child proc's pid
if ((proc = alloc_proc()) == NULL) {
goto fork_out;
}
proc->pid = get_pid();
proc->parent = current;
nr_process++;
if (setup_kstack(proc)) {
goto bad_fork_cleanup_proc;
}
if (copy_mm(clone_flags, proc)) {
goto bad_fork_cleanup_kstack;
}
copy_thread(proc, stack, tf);
hash_proc(proc);
list_add(&proc_list, &(proc->list_link));
wakeup_proc(proc);
ret = proc->pid;
fork_out:
return ret;
bad_fork_cleanup_kstack:
put_kstack(proc);
bad_fork_cleanup_proc:
kfree(proc);
goto fork_out;
}
// do_fork - parent process for a new child process
// 1. call alloc_proc to allocate a proc_struct
// 2. call setup_kstack to allocate a kernel stack for child process
// 3. call copy_mm to dup OR share mm according clone_flag
// 4. call wakup_proc to make the new child process RUNNABLE
int
do_fork(uint32_t clone_flags, uintptr_t stack, struct trapframe *tf) {
int ret = -E_NO_FREE_PROC;
struct proc_struct *proc;
if (nr_process >= MAX_PROCESS) {
goto fork_out;
}
ret = -E_NO_MEM;
if ((proc = alloc_proc()) == NULL) {
goto fork_out;
}
proc->parent = current;
if (setup_kstack(proc) != 0) {
goto bad_fork_cleanup_proc;
}
if (copy_mm(clone_flags, proc) != 0) {
goto bad_fork_cleanup_kstack;
}
copy_thread(proc, stack, tf);
unsigned long intr_flag;
local_irq_save(intr_flag);
{
proc->pid = get_pid();
hash_proc(proc);
list_add(&proc_list, &(proc->list_link));
nr_process ++;
}
local_irq_restore(intr_flag);
wakeup_proc(proc);
ret = proc->pid;
fork_out:
return ret;
bad_fork_cleanup_kstack:
put_kstack(proc);
bad_fork_cleanup_proc:
kfree(proc);
goto fork_out;
}
// do_fork - parent process for a new child process
// 1. call alloc_proc to allocate a proc_struct
// 2. call setup_kstack to allocate a kernel stack for child process
// 3. call copy_mm to dup OR share mm according clone_flag
// 4. call wakup_proc to make the new child process RUNNABLE
int
do_fork(uint32_t clone_flags, uintptr_t stack, struct trapframe *tf) {
int ret = -E_NO_FREE_PROC;
struct proc_struct *proc;
if (nr_process >= MAX_PROCESS) {
goto fork_out;
}
ret = -E_NO_MEM;
if ((proc = alloc_proc()) == NULL) {
goto fork_out;
}
proc->parent = current;
list_init(&(proc->thread_group));
assert(current->wait_state == 0);
assert(current->time_slice >= 0);
proc->time_slice = current->time_slice / 2;
current->time_slice -= proc->time_slice;
if (setup_kstack(proc) != 0) {
goto bad_fork_cleanup_proc;
}
if (copy_sem(clone_flags, proc) != 0) {
goto bad_fork_cleanup_kstack;
}
if (copy_fs(clone_flags, proc) != 0) {
goto bad_fork_cleanup_sem;
}
if ( copy_signal(clone_flags, proc) != 0 ) {
goto bad_fork_cleanup_fs;
}
if ( copy_sighand(clone_flags, proc) != 0 ) {
goto bad_fork_cleanup_signal;
}
if (copy_mm(clone_flags, proc) != 0) {
goto bad_fork_cleanup_sighand;
}
if (copy_thread(clone_flags, proc, stack, tf) != 0) {
goto bad_fork_cleanup_sighand;
}
bool intr_flag;
local_intr_save(intr_flag);
{
proc->pid = get_pid();
proc->tid = proc->pid;
hash_proc(proc);
set_links(proc);
if (clone_flags & CLONE_THREAD) {
list_add_before(&(current->thread_group), &(proc->thread_group));
proc->gid = current->gid;
}else{
proc->gid = proc->pid;
}
}
local_intr_restore(intr_flag);
wakeup_proc(proc);
ret = proc->pid;
fork_out:
return ret;
bad_fork_cleanup_sighand:
put_sighand(proc);
bad_fork_cleanup_signal:
put_signal(proc);
bad_fork_cleanup_fs:
put_fs(proc);
bad_fork_cleanup_sem:
put_sem_queue(proc);
bad_fork_cleanup_kstack:
put_kstack(proc);
bad_fork_cleanup_proc:
kfree(proc);
goto fork_out;
}