// Given a parent process's page table, create a copy
// of it for a child.
// CHANGE: copy on write
pde_t*
copyuvm(pde_t *pgdir, uint sz)
{
pde_t *d;
pte_t *pte;
uint pa, i, flags;
if((d = setupkvm()) == 0)
return 0;
// CHANGE TREINHART TO 4096
for(i = 4096; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void *) i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
*pte = *pte & (~PTE_W);
*pte = *pte | PTE_COW;
pa = PTE_ADDR(*pte);
flags = PTE_FLAGS(*pte);
//CHANGE: update reference counts
if(mappages(d, (void*)i, PGSIZE, pa, flags) < 0)
goto bad;
r_c.ref_count[pa/ 4096] ++;
}
flushtlb();
return d;
bad:
freevm(d);
return 0;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
asynwait(void)
{
struct proc *p;
int pid;
acquire(&ptable.lock);
// Scan through table looking for zombie children.
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
if(p->state == ZOMBIE){
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
freevm(p->pgdir);
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
release(&ptable.lock);
return -1;
}
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz)
{
pde_t *d;
pte_t *pte;
uint pa, i;
char *mem;
if((d = setupkvm()) == 0)
return 0;
for(i = PGSIZE; i < sz; i += PGSIZE) {
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
return d;
bad:
freevm(d);
return 0;
}
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz)
{
pde_t *d;
pte_t *pte;
uint pa, i, flags;
char *mem;
if((d = setupkvm()) == 0)
return 0;
for(i = 0; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void *) i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P)) continue;
// panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
flags = PTE_FLAGS(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)p2v(pa), PGSIZE);
if(mappages(d, (void*)i, PGSIZE, v2p(mem), flags) < 0)
goto bad;
}
return d;
bad:
freevm(d);
return 0;
}
static int restore(struct checkpoint_t *ch)
{
pde_t *d;
uint i;
char *mem;
if((d = setupkvm()) == 0)
return -1;
for(i = 0; i < ch->p.sz; i += PGSIZE){
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (ch->pages) + i, PGSIZE);
if(mappages(d, (char*)i, PGSIZE, v2p(mem), (ch->flags)[i / PGSIZE]) < 0)
goto bad;
}
struct proc np;
struct trapframe tf;
np.pgdir = d;
tf = ch->tf;
*np.tf = tf;
return procload(&np);
bad:
freevm(d);
return -1;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
int found_p = 0, first_p = 0;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
havekids = 1;
if(p->state == ZOMBIE && !p->is_thread && p->num_of_thread_child == 0){
found_p = p->pid;
break;
}
}
if(found_p){ // we found it a zombie procces with zombi kids (adams family)
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->pid != found_p){
continue;
}
if(!first_p)
{
freevm(p->pgdir);
first_p = 1;
}
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->killed = 0;
}
}
if(found_p){
release(&ptable.lock);
return pid;
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz)
{
pde_t *d;
pte_t *pte;
uint pa, i;
char *mem;
if((d = setupkvm()) == 0)
return 0;
//<(-
//CHANGED i = 0, < sz
for(i = PGSIZE; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 1)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P)){
panic("copyuvm: page not present");
}
else{
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
}
cprintf("Last addr copied from code: %x\n", i-PGSIZE);
//copy stack
for(i = USERTOP-proc->stacksz; i < USERTOP; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 1)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P)){
panic("copyuvm: page not present");
}
else{
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
}
cprintf("Last addr copied from code: %x\n", i-PGSIZE);
return d;
bad:
freevm(d);
return 0;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if((p->parent != proc) || (p->parentind > 0))
continue;
havekids = 1;
if((p->state == ZOMBIE)){
// Found one.
pid = p->pid;
cprintf("in wait by %s\n",p->name);
kfree(p->kstack);
p->kstack = 0;
if(!(ptable.proc[p->parentind]).children) {
//only free if p is the last reference to shared memory
cprintf("proc is %s\n",proc->name);
cprintf("freeing %s's pgdir\n",p->name);
freevm(p->pgdir);
}else{
(ptable.proc[p->parentind]).children--;
cprintf("%s children decremented to %d\n",ptable.proc[p->parentind].name,ptable.proc[p->parentind].children);
}
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
havekids = 1;
if(p->state == ZOMBIE){
cprintf("my pid is %d\n", proc->pid);
cprintf("killing my child, process %d\n", p->pid);
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
int j;
for(j = 0; j < 4; j++) {
proc->child_shmems[j] = p->shmems[j];
}
freevm(p->pgdir);
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// TODO(byan23): Copy the stack at the end of addr space.
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz)
{
pde_t *d;
pte_t *pte;
uint pa, i;
char *mem;
if((d = setupkvm()) == 0)
return 0;
// Copy code + heap.
if (proc->pid == 1) i = 0;
else i = PGSIZE;
for(; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
//cprintf("before coping stack from pid %d.\n", proc->pid);
// TODO(byan23): Copy more stack as it grows.
// Copy stack.
i = USERTOP - proc->ssz;
//i = USERTOP - PGSIZE;
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
return d;
bad:
freevm(d);
return 0;
}
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz, uint s_sz)
{
pde_t *d;
pte_t *pte;
uint pa, i, stack_size;
char *mem;
if((d = setupkvm()) == 0)
return 0;
// Start at PGSIZE to make the first page invalid
for(i = PGSIZE; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
// We need to loop again to copy the stack over
stack_size = s_sz;
for(i = stack_size; i < USERTOP; i+= PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
return d;
bad:
freevm(d);
return 0;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
havekids = 1;
if(p->state == ZOMBIE){
// Found one.
pid = p->pid;
// free VM and stack only if child is not a thread
if(p->isthread == 0){
kfree(p->kstack);
freevm(p->pgdir);
}
p->kstack = 0;
p->pgdir = 0;
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
return 0;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
havekids = 1;
if(p->state == ZOMBIE){
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
freevm(p->pgdir);
p->state = UNUSED;
#ifdef USE_CS333_SCHEDULER
addToFreeList(p);
#endif
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
//cprintf("Urmish in wait proc %s\n",proc->name);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != proc)
continue;
havekids = 1;
if(p->state == ZOMBIE){
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
freevm(p->pgdir);
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
//cprintf("Urmish in wait bitiya nahi milat \n");
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
acquire(&ptable.lock);
for(;;){
// Scan through table looking for zombie children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
//going through the process table
if(p->parent != proc || p->clonecalled == 1) //if it is not the parent
continue;
havekids = 1;//means proc has kids
if(p->state == ZOMBIE){//zombie means that it is done running but
//has not terminated
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
freevm(p->pgdir);//frees addr space
p->state = UNUSED;
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || proc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(proc, &ptable.lock); //DOC: wait-sleep
}
}
// Given a parent process's page table, create a copy
// of it for a child.
pgd_t* copyuvm (pgd_t *pgdir, uint sz)
{
pgd_t *d;
pte_t *pte;
uint64 pa, i, ap;
char *mem;
// allocate a new first level page directory
d = kpt_alloc();
if (d == NULL ) {
return NULL ;
}
// copy the whole address space over (no COW)
for (i = 0; i < sz; i += PTE_SZ) {
if ((pte = walkpgdir(pgdir, (void *) i, 0)) == 0) {
panic("copyuvm: pte should exist");
}
if (!(*pte & (ENTRY_PAGE | ENTRY_VALID))) {
panic("copyuvm: page not present");
}
pa = PTE_ADDR (*pte);
ap = PTE_AP (*pte);
if ((mem = alloc_page()) == 0) {
goto bad;
}
memmove(mem, (char*) p2v(pa), PTE_SZ);
if (mappages(d, (void*) i, PTE_SZ, v2p(mem), ap) < 0) {
goto bad;
}
}
return d;
bad: freevm(d);
return 0;
}
// Given a parent process's page table, create a copy
// of it for a child.
pde_t*
copyuvm(pde_t *pgdir, uint sz, uint stack_addr)
{
pde_t *d;
pte_t *pte;
uint pa, i;
char *mem;
if((d = setupkvm()) == 0)
return 0;
for(i = PGSIZE; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void*)i, 0)) == 0)
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
pa = PTE_ADDR(*pte);
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE);
if(mappages(d, (void*)i, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)
goto bad;
}
// Copy the last page which is the new stack
if((pte = walkpgdir(pgdir, (void*)(USERTOP-PGSIZE), 1)) == 0)//undestand what pgdir does
panic("copyuvm: pte should exist");
if(!(*pte & PTE_P))
panic("copyuvm: page not present");
//cprintf(" last page is %d\n",pte);
pa = PTE_ADDR(*pte);// what pa are they getting from pte
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)pa, PGSIZE); // copying some stuff.. figure out what 1 page is and copying it
if(mappages(d, (void*)USERTOP-PGSIZE, PGSIZE, PADDR(mem), PTE_W|PTE_U) < 0)//mapping into new address space and making it valid
goto bad;
return d;
bad:
freevm(d);
return 0;
}
// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
struct proc *p;
int havekids, pid;
struct proc *curproc = myproc();
acquire(&ptable.lock);
for(;;){
// Scan through table looking for exited children.
havekids = 0;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->parent != curproc)
continue;
havekids = 1;
if(p->state == ZOMBIE){
// Found one.
pid = p->pid;
kfree(p->kstack);
p->kstack = 0;
freevm(p->pgdir);
p->pid = 0;
p->parent = 0;
p->name[0] = 0;
p->killed = 0;
p->state = UNUSED;
release(&ptable.lock);
return pid;
}
}
// No point waiting if we don't have any children.
if(!havekids || curproc->killed){
release(&ptable.lock);
return -1;
}
// Wait for children to exit. (See wakeup1 call in proc_exit.)
sleep(curproc, &ptable.lock); //DOC: wait-sleep
}
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz,s_sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
sz = PGSIZE;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate a one-page stack one page away from USERTOP (at bottom
// grow upwards)
s_sz = (USERTOP - PGSIZE);
if((s_sz = allocuvm(pgdir, s_sz, s_sz + PGSIZE)) == 0)
goto bad;
// Push argument strings, prepare rest of stack in ustack.
sp = s_sz;
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp -= strlen(argv[argc]) + 1;
sp &= ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
s_sz = USERTOP - PGSIZE;
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->s_sz =s_sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
// cprintf("finish exec%d\t%d\n",sz,s_sz);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
cprintf("-(%d)exec...\n",proc->pid);
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
// sx: passed Part 1
sz = PGSIZE;//PGSIZW = 4K
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
//no need to modify above/////////////////////////
// Allocate a one-page stack at the next page boundary
sz = PGROUNDUP(sz);
/*
if((sz = allocuvm(pgdir, sz, sz + PGSIZE)) == 0)
goto bad;
sp = sz;
*/
// Push argument strings, prepare rest of stack in ustack.
// sx:tst1/////////////////
int sz_stack= 0;
if((sz_stack = allocuvm(pgdir, USERTOP-PGSIZE, USERTOP))==0)
panic("allocuvm sz_stack failed\n");
sp = sz_stack;
/////////////////////////
cprintf("-exec: sp(%d)\n",sp);
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp -= strlen(argv[argc]) + 1;
sp &= ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
cprintf("-exec:sz(%d)sp(%d)sz-sp(%d)elf.entry(%d)\n",sz,sp,USERTOP-sp,elf.entry);
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz_stack;//current stack bottom
proc->sz_stack = sz_stack-PGSIZE;//current stack top
proc->sz_heap = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
cprintf("-exec end***\n");
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
char tmp_path[MAX_LNK_NAME]; /* A&T */
/* A&T use readlink to de-reference symbolic links */
if (k_readlink(path, tmp_path, MAX_LNK_NAME) != -1) {
if((ip = namei(tmp_path)) == 0)
return -1;
} else {
if((ip = namei(path)) == 0)
return -1;
}
ilock(ip);
//A&T checks if symlink
/* for (i=0;i < 16 ; i++) { //prevents loops ,up to 16 chain links */
/* if (ip->flags & I_SYMLNK) { */
/* if((sym_ip = namei((char*)ip->addrs)) == 0) { */
/* iunlock(ip); */
/* return -1; */
/* } */
/* iunlock(ip); */
/* ip = sym_ip; */
/* ilock(ip); */
/* } else */
/* break; */
/* } */
/* if (i == 16) { */
/* panic("symbolic link exceeds 16 links "); */
/* } */
//A&T - end
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm(kalloc)) == 0)
goto bad;
// Load program into memory.
sz = 0;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
// Skip first page
sz = PGSIZE;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate a one-page stack at the next page boundary
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + PGSIZE)) == 0)
goto bad;
// Push argument strings, prepare rest of stack in ustack.
sp = sz;
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp -= strlen(argv[argc]) + 1;
sp &= ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
// Set end of shared pages address to USERTOP
proc->endSP = USERTOP;
proc->sz = sz;
// For each shared page set the shared page count to the memory count
for (i = 0; i < SHMEM_PAGES; i++) {
proc->shared_count[i] = mem_count[i];
}
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
// namei converts given path into inode
begin_op();
if((ip = namei(path)) == 0){
end_op();
return -1;
}
ilock(ip);
pgdir = 0;
// Check ELF header
// if the file is smaller than the size of an elf header,
// then it doesn't hold an elf header. (ERROR)
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
// do this for each section of the elf file (chunk size dlineated
// by sizeof program header)
// allocate user virtual memory
// load program into user virtual memory
// in linux, run readelf -a /bin/ls and see the the offset and size
// column program section header being loaded
sz = 0;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
end_op();
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz); // This is macro function that jumps to the next page boundary
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
// this makes the inaccessible page
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
// This code is building the stack frame of the application.
// since argc is not passed into this function, to find the max
// num of args, we need to step through the argv string until the
// item returned is NULL or the end of the string.
// This means that we have found all of the arguments.
// Next, we need to copy each argument into the stack and keep
// references to it in a local stack. Once this is done, we can
// set the stack pointer to point to the first argument on the stack.
// now, we can put the return value and the total number of args onto our
// local stack. Then, we must prepare local stack for the copy into the
// real stack. Next, we adjust the real stack pointer to make
// room for our local stack and then we copy our stack that contains
// pointers to each argument onto the stack.
// We need this for quick lookup of each argument -- without the poitners
// we can't efficiently get the args back. we also need the
// the total number of arguments to make sure that we are growing the
// stack properly.
// think about this: int main(int argc, char **argv);
// this code defends why we need a double pointer to a char.
// we are giving an array of char *.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
// explain of ~3 in following line:
// to make memory align with 4 bits, we the two lower order bit
// which are the oly two bits that aren't divisibile by 4.
// this is to keep the compiler aligned with the system
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
// This is getting the real stack ready for the copy
// of the local stack, ustack[]
ustack[2] = sp - (argc+1)*4; // argv pointer
// this is moving the stack pointer to the location of first argument.
sp -= (3+argc+1) * 4;
// This is copying the ustack[] into the real stack
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// done buildng the stack frame
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip){
iunlockput(ip);
end_op();
}
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
begin_op();
if((ip = namei(path)) == 0){
end_op();
return -1;
}
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
sz = 0;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
end_op();
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip){
iunlockput(ip);
end_op();
}
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm(kalloc)) == 0)
goto bad;
// Load program into memory.
// leave first page inaccessible (to make NULL ref fail)
sz = PGSIZE-1;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// hook up the old shared memory to the new addr space
// (no need to change refcount, because the old ref goes away with
// this exec, so it's +1 then -1 => 0 change
if (proc->shared) {
extern void mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm);
mappages(pgdir, (char *)SHARED_V, PGSIZE, v2p(proc->shared->page), PTE_W|PTE_U);
}
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
//// section check (either exist interp section)
//// needed libsample.so.1
if (strcmp("share_main", path) == 0)
{
// share loader process (dummy of load ld-linux.so.2)
//// mmap share library (libsample.so).
sz = 0;
/////// alloc physical memory
cprintf("start %d \n", sz);
ph.vaddr = 0x08048000;
ph.memsz = 0x031a4 + 0x00130;
sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz);
cprintf("start4 %d \n", sz);
/////// map pages to physical memory
ph.off = 0x0;
ph.filesz = 0x21a4 + 0x00124;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
cprintf("start3 %d \n", sz);
iunlockput(ip);
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = 0x80486d4; //.text
proc->tf->esp = sp;
cprintf("start2 %d \n", sz);
switchuvm(proc);
freevm(oldpgdir);
return 0;
//// rewrite bss valiable.
//// stay loader program for delayed load.
}
// Load program into memory.
sz = 0;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate two pages at the next page boundary.
// Make the first inaccessible. Use the second as the user stack.
sz = PGROUNDUP(sz);
if((sz = allocuvm(pgdir, sz, sz + 2*PGSIZE)) == 0)
goto bad;
clearpteu(pgdir, (char*)(sz - 2*PGSIZE));
sp = sz;
// Push argument strings, prepare rest of stack in ustack.
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp = (sp - (strlen(argv[argc]) + 1)) & ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sz_stk, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
sz = PGSIZE;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
sz = PGROUNDUP(sz);
// CHANGE: Allocates the first page of the stack at the end of the user programs address space
if((allocuvm(pgdir, USERTOP - PGSIZE, USERTOP)) == 0)
goto bad;
/* CHANGE: sets the sz_stk field equal to the top address of the stack */
sz_stk = USERTOP - PGSIZE;
// Push argument strings, prepare rest of stack in ustack.
sp = USERTOP; /* CHANGE: sets the stack pointer to the botom of the user space. */
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp -= strlen(argv[argc]) + 1;
sp &= ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// Commit to the user image.
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->sz_stk = sz_stk;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint argc, sz, sp, ustack[3+MAXARG+1];
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad;
if(elf.magic != ELF_MAGIC)
goto bad;
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
sz = PGSIZE;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
if(ph.type != ELF_PROG_LOAD)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
//cprintf("exec: size: %d, phva: %d phvamem:%d \n", sz, ph.va , ph.memsz);
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
ip = 0;
// Allocate a one-page stack at the next page boundary
sz = PGROUNDUP(sz);
//if((sz = allocuvm(pgdir, sz, sz + PGSIZE)) == 0)
// goto bad;
uint stkptr = allocuvm(pgdir, USERTOP - PGSIZE, USERTOP);
if(stkptr == 0) panic("dont know wht to do");
//proc->stkptr = USERTOP-PGSIZE;
//cprintf("stkptr is : %d\n", stkptr);
// Push argument strings, prepare rest of stack in ustack.
sp = stkptr;
for(argc = 0; argv[argc]; argc++) {
if(argc >= MAXARG)
goto bad;
sp -= strlen(argv[argc]) + 1;
sp &= ~3;
if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0)
goto bad;
ustack[3+argc] = sp;
//cprintf("sp value: %d\n",sp);
}
ustack[3+argc] = 0;
ustack[0] = 0xffffffff; // fake return PC
ustack[1] = argc;
ustack[2] = sp - (argc+1)*4; // argv pointer
sp -= (3+argc+1) * 4;
if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0)
goto bad;
// Save program name for debugging.
for(last=s=path; *s; s++)
if(*s == '/')
last = s+1;
safestrcpy(proc->name, last, sizeof(proc->name));
// remzi video change
//uint newstk = allocuvm(pgdir, USERTOP - PGSIZE, USERTOP);
//if(newstk == 0) panic("dont know wht to do");
// Commit to the user image.
proc->stkptr = USERTOP - PGSIZE;
//proc->grdptr = USERTOP - PGSIZE - PGSIZE;
oldpgdir = proc->pgdir;
proc->pgdir = pgdir;
proc->sz = sz;
proc->tf->eip = elf.entry; // main
proc->tf->esp = sp;
switchuvm(proc);
freevm(oldpgdir);
return 0;
bad:
if(pgdir)
freevm(pgdir);
if(ip)
iunlockput(ip);
return -1;
}
