You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
248 lines
6.2 KiB
248 lines
6.2 KiB
/*
|
|
* linux/kernel/fork.c
|
|
*
|
|
* (C) 1991 Linus Torvalds
|
|
*/
|
|
|
|
/*
|
|
* 'fork.c' contains the help-routines for the 'fork' system call
|
|
* (see also system_call.s), and some misc functions ('verify_area').
|
|
* Fork is rather simple, once you get the hang of it, but the memory
|
|
* management can be a bitch. See 'mm/mm.c': 'copy_page_tables()'
|
|
*/
|
|
#include <errno.h>
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/kernel.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/system.h>
|
|
|
|
extern void write_verify(unsigned long address);
|
|
|
|
long last_pid=0;
|
|
|
|
void verify_area(void * addr,int size)
|
|
{
|
|
unsigned long start;
|
|
|
|
start = (unsigned long) addr;
|
|
size += start & 0xfff;
|
|
start &= 0xfffff000;
|
|
start += get_base(current->ldt[2]);
|
|
while (size>0) {
|
|
size -= 4096;
|
|
write_verify(start);
|
|
start += 4096;
|
|
}
|
|
}
|
|
|
|
int copy_mem(int nr,struct task_struct * p)
|
|
{
|
|
unsigned long old_data_base,new_data_base,data_limit;
|
|
unsigned long old_code_base,new_code_base,code_limit;
|
|
|
|
code_limit=get_limit(0x0f);
|
|
data_limit=get_limit(0x17);
|
|
old_code_base = get_base(current->ldt[1]);
|
|
old_data_base = get_base(current->ldt[2]);
|
|
if (old_data_base != old_code_base)
|
|
panic("We don't support separate I&D");
|
|
if (data_limit < code_limit)
|
|
panic("Bad data_limit");
|
|
new_data_base = new_code_base = nr * 0x4000000;
|
|
p->start_code = new_code_base;
|
|
set_base(p->ldt[1],new_code_base);
|
|
set_base(p->ldt[2],new_data_base);
|
|
if (copy_page_tables(old_data_base,new_data_base,data_limit)) {
|
|
free_page_tables(new_data_base,data_limit);
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Ok, this is the main fork-routine. It copies the system process
|
|
* information (task[nr]) and sets up the necessary registers. It
|
|
* also copies the data segment in it's entirety.
|
|
*/
|
|
int copy_process(int nr,long ebp,long edi,long esi,long gs,long none,
|
|
long ebx,long ecx,long edx,
|
|
long fs,long es,long ds,
|
|
long eip,long cs,long eflags,long esp,long ss)
|
|
{
|
|
struct task_struct *p;
|
|
int i;
|
|
struct file *f;
|
|
|
|
p = (struct task_struct *) get_free_page();
|
|
if (!p)
|
|
return -EAGAIN;
|
|
task[nr] = p;
|
|
__asm__ volatile ("cld"); /* by wyj */
|
|
*p = *current; /* NOTE! this doesn't copy the supervisor stack */
|
|
p->state = TASK_UNINTERRUPTIBLE;
|
|
p->pid = last_pid;
|
|
p->father = current->pid;
|
|
p->counter = p->priority;
|
|
p->signal = 0;
|
|
p->alarm = 0;
|
|
p->leader = 0; /* process leadership doesn't inherit */
|
|
p->utime = p->stime = 0;
|
|
p->cutime = p->cstime = 0;
|
|
p->start_time = jiffies;
|
|
p->tss.back_link = 0;
|
|
p->tss.esp0 = PAGE_SIZE + (long) p;
|
|
p->tss.ss0 = 0x10;
|
|
p->tss.eip = eip;
|
|
p->tss.eflags = eflags;
|
|
p->tss.eax = 0;
|
|
p->tss.ecx = ecx;
|
|
p->tss.edx = edx;
|
|
p->tss.ebx = ebx;
|
|
p->tss.esp = esp;
|
|
p->tss.ebp = ebp;
|
|
p->tss.esi = esi;
|
|
p->tss.edi = edi;
|
|
p->tss.es = es & 0xffff;
|
|
p->tss.cs = cs & 0xffff;
|
|
p->tss.ss = ss & 0xffff;
|
|
p->tss.ds = ds & 0xffff;
|
|
p->tss.fs = fs & 0xffff;
|
|
p->tss.gs = gs & 0xffff;
|
|
p->tss.ldt = _LDT(nr);
|
|
p->tss.trace_bitmap = 0x80000000;
|
|
if (last_task_used_math == current)
|
|
__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
|
|
if (copy_mem(nr,p)) {
|
|
task[nr] = NULL;
|
|
free_page((long) p);
|
|
return -EAGAIN;
|
|
}
|
|
for (i=0; i<NR_OPEN;i++)
|
|
if (f=p->filp[i])
|
|
f->f_count++;
|
|
if (current->pwd)
|
|
current->pwd->i_count++;
|
|
if (current->root)
|
|
current->root->i_count++;
|
|
if (current->executable)
|
|
current->executable->i_count++;
|
|
set_tss_desc(gdt+(nr<<1)+FIRST_TSS_ENTRY,&(p->tss));
|
|
set_ldt_desc(gdt+(nr<<1)+FIRST_LDT_ENTRY,&(p->ldt));
|
|
p->state = TASK_RUNNING; /* do this last, just in case */
|
|
return last_pid;
|
|
}
|
|
int copy_mem1(int nr,struct task_struct * p)
|
|
{
|
|
unsigned long old_data_base,new_data_base,data_limit;
|
|
unsigned long old_code_base,new_code_base,code_limit;
|
|
|
|
code_limit=get_limit(0x0f);
|
|
data_limit=get_limit(0x17);
|
|
old_code_base = get_base(current->ldt[1]);
|
|
old_data_base = get_base(current->ldt[2]);
|
|
if (old_data_base != old_code_base)
|
|
panic("We don't support separate I&D");
|
|
if (data_limit < code_limit)
|
|
panic("Bad data_limit");
|
|
new_data_base = new_code_base = nr * 0x4000000;
|
|
p->start_code = new_code_base;
|
|
set_base(p->ldt[1],new_code_base);
|
|
set_base(p->ldt[2],new_data_base);
|
|
if (copy_page_tables1(old_data_base,new_data_base,data_limit)) {
|
|
free_page_tables(new_data_base,data_limit);
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
int copy_clone(int nr,long ebp,long edi,long esi,long gs,long none,
|
|
long ebx,long ecx,long edx,
|
|
long fs,long es,long ds,
|
|
long eip,long cs,long eflags,long esp,long ss)
|
|
{
|
|
struct task_struct *p;
|
|
int i;
|
|
struct file *f;
|
|
|
|
p = (struct task_struct *) get_free_page();
|
|
if (!p)
|
|
return -EAGAIN;
|
|
task[nr] = p;
|
|
__asm__ volatile ("cld"); /* by wyj */
|
|
*p = *current; /* NOTE! this doesn't copy the supervisor stack */
|
|
p->state = TASK_UNINTERRUPTIBLE;
|
|
p->pid = last_pid;
|
|
p->father = current->pid;
|
|
p->counter = p->priority;
|
|
p->signal = 0;
|
|
p->alarm = 0;
|
|
p->leader = 0; /* process leadership doesn't inherit */
|
|
p->utime = p->stime = 0;
|
|
p->cutime = p->cstime = 0;
|
|
p->start_time = jiffies;
|
|
p->tss.back_link = 0;
|
|
p->tss.esp0 = PAGE_SIZE + (long) p;
|
|
p->tss.ss0 = 0x10;
|
|
p->tss.eip = ebx;
|
|
p->tss.eflags = eflags;
|
|
p->tss.eax = 0;
|
|
p->tss.ecx = ecx;
|
|
p->tss.edx = edx;
|
|
p->tss.ebx = ebx;
|
|
p->tss.esp = ecx;
|
|
p->tss.ebp = ebp;
|
|
p->tss.esi = esi;
|
|
p->tss.edi = edi;
|
|
p->tss.es = es & 0xffff;
|
|
p->tss.cs = cs & 0xffff;
|
|
p->tss.ss = ss & 0xffff;
|
|
p->tss.ds = ds & 0xffff;
|
|
p->tss.fs = fs & 0xffff;
|
|
p->tss.gs = gs & 0xffff;
|
|
p->tss.ldt = _LDT(nr);
|
|
p->tss.trace_bitmap = 0x80000000;
|
|
if (last_task_used_math == current)
|
|
__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
|
|
if(edx&0x100){
|
|
if (copy_mem1(nr,p)) {
|
|
task[nr] = NULL;
|
|
free_page((long) p);
|
|
return -EAGAIN;
|
|
}
|
|
}
|
|
else{
|
|
if (copy_mem(nr,p)) {
|
|
task[nr] = NULL;
|
|
free_page((long) p);
|
|
return -EAGAIN;
|
|
}
|
|
}
|
|
for (i=0; i<NR_OPEN;i++)
|
|
if (f=p->filp[i])
|
|
f->f_count++;
|
|
if (current->pwd)
|
|
current->pwd->i_count++;
|
|
if (current->root)
|
|
current->root->i_count++;
|
|
if (current->executable)
|
|
current->executable->i_count++;
|
|
set_tss_desc(gdt+(nr<<1)+FIRST_TSS_ENTRY,&(p->tss));
|
|
set_ldt_desc(gdt+(nr<<1)+FIRST_LDT_ENTRY,&(p->ldt));
|
|
p->state = TASK_RUNNING; /* do this last, just in case */
|
|
return last_pid;
|
|
}
|
|
|
|
int find_empty_process(void)
|
|
{
|
|
int i;
|
|
|
|
repeat:
|
|
if ((++last_pid)<0) last_pid=1;
|
|
for(i=0 ; i<NR_TASKS ; i++)
|
|
if (task[i] && task[i]->pid == last_pid) goto repeat;
|
|
for(i=1 ; i<NR_TASKS ; i++)
|
|
if (!task[i])
|
|
return i;
|
|
return -EAGAIN;
|
|
}
|