/*
* Copyright (C) 2000-2003, Axis Communications AB.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
/*
* Determines which bits in DCCR the user has access to.
* 1 = access, 0 = no access.
*/
#define DCCR_MASK 0x0000001f /* XNZVC */
/*
* Get contents of register REGNO in task TASK.
*/
inline long get_reg(struct task_struct *task, unsigned int regno)
{
/* USP is a special case, it's not in the pt_regs struct but
* in the tasks thread struct
*/
if (regno == PT_USP)
return task->thread.usp;
else if (regno < PT_MAX)
return ((unsigned long *)user_regs(task->thread_info))[regno];
else
return 0;
}
/*
* Write contents of register REGNO in task TASK.
*/
inline int put_reg(struct task_struct *task, unsigned int regno,
unsigned long data)
{
if (regno == PT_USP)
task->thread.usp = data;
else if (regno < PT_MAX)
((unsigned long *)user_regs(task->thread_info))[regno] = data;
else
return -1;
return 0;
}
/*
* Called by kernel/ptrace.c when detaching.
*
* Make sure the single step bit is not set.
*/
void
ptrace_disable(struct task_struct *child)
{
/* Todo - pending singlesteps? */
}
/*
* Note that this implementation of ptrace behaves differently from vanilla
* ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
* PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
* ignored. Instead, the data variable is expected to point at a location
* (in user space) where the result of the ptrace call is written (instead of
* being returned).
*/
asmlinkage int
sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
int ret;
unsigned long __user *datap = (unsigned long __user *)data;
lock_kernel();
ret = -EPERM;
if (request == PTRACE_TRACEME) {
if (current->ptrace & PT_PTRACED)
goto out;
current->ptrace |= PT_PTRACED;
ret = 0;
goto out;
}
ret = -ESRCH;
read_lock(&tasklist_lock);
child = find_task_by_pid(pid);
if (child)
get_task_struct(child);
read_unlock(&tasklist_lock);
if (!child)
goto out;
ret = -EPERM;
if (pid == 1) /* Leave the init process alone! */
goto out_tsk;
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
goto out_tsk;
}
ret = ptrace_check_attach(child, request == PTRACE_KILL);
if (ret < 0)
goto out_tsk;
switch (request) {
/* Read word at location address. */
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA: {
unsigned long tmp;
int copied;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
ret = -EIO;
if (copied != sizeof(tmp))
break;
ret = put_user(tmp,datap);
break;
}
/* Read the word at location address in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
break;
tmp = get_reg(child, addr >> 2);
ret = put_user(tmp, datap);
break;
}
/* Write the word at location address. */
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
break;
ret = -EIO;
break;
/* Write the word at location address in the USER area. */
case PTRACE_POKEUSR:
ret = -EIO;
if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
break;
addr >>= 2;
if (addr == PT_DCCR) {
/* don't allow the tracing process to change stuff like
* interrupt enable, kernel/user bit, dma enables etc.
*/
data &= DCCR_MASK;
data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
if (put_reg(child, addr, data))
break;
ret = 0;
break;
case PTRACE_SYSCALL:
case PTRACE_CONT:
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
if (request == PTRACE_SYSCALL) {
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
else {
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
child->exit_code = data;
/* TODO: make sure any pending breakpoint is killed */
wake_up_process(child);
ret = 0;
break;
/* Make the child exit by sending it a sigkill. */
case PTRACE_KILL:
ret = 0;
if (child->state == TASK_ZOMBIE)
break;
child->exit_code = SIGKILL;
/* TODO: make sure any pending breakpoint is killed */
wake_up_process(child);
break;
/* Set the trap flag. */
case PTRACE_SINGLESTEP:
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
/* TODO: set some clever breakpoint mechanism... */
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
/* Get all GP registers from the child. */
case PTRACE_GETREGS: {
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
tmp = get_reg(child, i);
if (put_user(tmp, datap)) {
ret = -EFAULT;
goto out_tsk;
}
data += sizeof(long);
}
ret = 0;
break;
}
/* Set all GP registers in the child. */
case PTRACE_SETREGS: {
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
if (get_user(tmp, datap)) {
ret = -EFAULT;
goto out_tsk;
}
if (i == PT_DCCR) {
tmp &= DCCR_MASK;
tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
put_reg(child, i, tmp);
data += sizeof(long);
}
ret = 0;
break;
}
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
put_task_struct(child);
out:
unlock_kernel();
return ret;
}
void do_syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* This isn't the same as continuing with a signal, but it will do for
* normal use.
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
