/*
* Create a new thread based on an existing one.
* The new thread has name NAME, and starts executing in function FUNC.
* DATA1 and DATA2 are passed to FUNC.
*/
int
thread_fork(const char *name,
void *data1, unsigned long data2,
void (*func)(void *, unsigned long),
struct thread **ret)
{
struct thread *newguy;
int s, result;
/* Allocate a thread */
newguy = thread_create(name);
if (newguy==NULL) {
return ENOMEM;
}
/* Allocate a stack */
newguy->t_stack = kmalloc(STACK_SIZE);
if (newguy->t_stack==NULL) {
kfree(newguy->t_name);
kfree(newguy);
return ENOMEM;
}
/* stick a magic number on the bottom end of the stack */
newguy->t_stack[0] = 0xae;
newguy->t_stack[1] = 0x11;
newguy->t_stack[2] = 0xda;
newguy->t_stack[3] = 0x33;
/* Inherit the current directory */
if (curthread->t_cwd != NULL) {
VOP_INCREF(curthread->t_cwd);
newguy->t_cwd = curthread->t_cwd;
}
#if OPT_A2
if(curthread->forkcalled) {
int i, res, spl;
//copy address space
res = as_copy(curthread->t_vmspace,&newguy->t_vmspace);
if (res) {
//kprintf("as_copy failed in thread_fork, curthread_vmspace_addr: %p, newguy_vmspace_addr: %p\n", curthread->t_vmspace, newguy->t_vmspace);
return res;
}
as_activate(curthread->t_vmspace); /* FIXME if wrong comment this out and retry */
//copy vnodes
// spl = splhigh();
for(i=3;i<MAX_OPENED_FILES;i++) {
if(curthread->files[i]!=NULL) {
newguy->files[i] = files_create(kstrdup(curthread->files[i]->filename), curthread->files[i]->vn, curthread->files[i]->flags);
VOP_INCOPEN(newguy->files[i]->vn);
VOP_INCREF(newguy->files[i]->vn);
} else {
break;
}
}
// splx(spl);
curthread->forkcalled = 0;
}
#endif
/* Set up the pcb (this arranges for func to be called) */
md_initpcb(&newguy->t_pcb, newguy->t_stack, data1, data2, func);
/* Interrupts off for atomicity */
s = splhigh();
/*
* Make sure our data structures have enough space, so we won't
* run out later at an inconvenient time.
*/
result = array_preallocate(sleepers, numthreads+1);
if (result) {
goto fail;
}
result = array_preallocate(zombies, numthreads+1);
if (result) {
goto fail;
}
/* Do the same for the scheduler. */
result = scheduler_preallocate(numthreads+1);
if (result) {
goto fail;
}
/* Make the new thread runnable */
result = make_runnable(newguy);
if (result != 0) {
goto fail;
}
/*
* Increment the thread counter. This must be done atomically
* with the preallocate calls; otherwise the count can be
* temporarily too low, which would obviate its reason for
* existence.
*/
numthreads++;
/* Done with stuff that needs to be atomic */
splx(s);
/*
* Return new thread structure if it's wanted. Note that
* using the thread structure from the parent thread should be
* done only with caution, because in general the child thread
* might exit at any time.
*/
if (ret != NULL) {
*ret = newguy;
}
return 0;
fail:
splx(s);
if (newguy->t_cwd != NULL) {
VOP_DECREF(newguy->t_cwd);
}
kfree(newguy->t_stack);
kfree(newguy->t_name);
kfree(newguy);
return result;
}
/* Does most of the work for open(). */
int
vfs_open(char *path, int openflags, struct vnode **ret)
{
int how;
int result;
int canwrite;
struct vnode *vn = NULL;
how = openflags & O_ACCMODE;
switch (how) {
case O_RDONLY:
canwrite=0;
break;
case O_WRONLY:
case O_RDWR:
canwrite=1;
break;
default:
return EINVAL;
}
if (openflags & O_CREAT) {
char name[NAME_MAX+1];
struct vnode *dir;
int excl = (openflags & O_EXCL)!=0;
result = vfs_lookparent(path, &dir, name, sizeof(name));
if (result) {
return result;
}
result = VOP_CREAT(dir, name, excl, &vn);
VOP_DECREF(dir);
}
else {
result = vfs_lookup(path, &vn);
}
if (result) {
return result;
}
assert(vn != NULL);
result = VOP_OPEN(vn, openflags);
if (result) {
VOP_DECREF(vn);
return result;
}
VOP_INCOPEN(vn);
if (openflags & O_TRUNC) {
if (canwrite==0) {
result = EINVAL;
}
else {
result = VOP_TRUNCATE(vn, 0);
}
if (result) {
VOP_DECOPEN(vn);
VOP_DECREF(vn);
return result;
}
}
*ret = vn;
return 0;
}
