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/* ptrace.c */
/* By Ross Biro 1/23/92 */
/*
* Pentium III FXSR, SSE support
* Gareth Hughes <gareth@valinux.com>, May 2000
*/
#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/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/debugreg.h>
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/* determines which flags the user has access to. */
/* 1 = access 0 = no access */
#define FLAG_MASK 0x00044dd5
/* set's the trap flag. */
#define TRAP_FLAG 0x100
/*
* Offset of eflags on child stack..
*/
#define EFL_OFFSET ((EFL-2)*4-sizeof(struct pt_regs))
/*
* this routine will get a word off of the processes privileged stack.
* the offset is how far from the base addr as stored in the TSS.
* this routine assumes that all the privileged stacks are in our
* data space.
*/
static inline int get_stack_long(struct task_struct *task, int offset)
{
unsigned char *stack;
stack = (unsigned char *)task->thread.esp0;
stack += offset;
return (*((int *)stack));
}
/*
* this routine will put a word on the processes privileged stack.
* the offset is how far from the base addr as stored in the TSS.
* this routine assumes that all the privileged stacks are in our
* data space.
*/
static inline int put_stack_long(struct task_struct *task, int offset,
unsigned long data)
{
unsigned char * stack;
stack = (unsigned char *) task->thread.esp0;
stack += offset;
*(unsigned long *) stack = data;
return 0;
}
static int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
{
switch (regno >> 2) {
case FS:
if (value && (value & 3) != 3)
return -EIO;
child->thread.fs = value;
return 0;
case GS:
if (value && (value & 3) != 3)
return -EIO;
child->thread.gs = value;
return 0;
case DS:
case ES:
if (value && (value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case SS:
case CS:
if ((value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case EFL:
value &= FLAG_MASK;
value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
break;
}
if (regno > GS*4)
regno -= 2*4;
put_stack_long(child, regno - sizeof(struct pt_regs), value);
return 0;
}
static unsigned long getreg(struct task_struct *child,
unsigned long regno)
{
unsigned long retval = ~0UL;
switch (regno >> 2) {
case FS:
retval = child->thread.fs;
break;
case GS:
retval = child->thread.gs;
break;
case DS:
case ES:
case SS:
case CS:
retval = 0xffff;
/* fall through */
default:
if (regno > GS*4)
regno -= 2*4;
regno = regno - sizeof(struct pt_regs);
retval &= get_stack_long(child, regno);
}
return retval;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
long tmp;
tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
put_stack_long(child, EFL_OFFSET, tmp);
}
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
struct user * dummy = NULL;
int i, ret;
lock_kernel();
ret = -EPERM;
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->ptrace & PT_PTRACED)
goto out;
/* set the ptrace bit in the process flags. */
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) /* you may not mess with init */
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) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKTEXT: /* read word at location addr. */
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,(unsigned long *) data);
break;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0 ||
addr > sizeof(struct user) - 3)
break;
tmp = 0; /* Default return condition */
if(addr < FRAME_SIZE*sizeof(long))
tmp = getreg(child, addr);
if(addr >= (long) &dummy->u_debugreg[0] &&
addr <= (long) &dummy->u_debugreg[7]){
addr -= (long) &dummy->u_debugreg[0];
addr = addr >> 2;
tmp = child->thread.debugreg[addr];
}
ret = put_user(tmp,(unsigned long *) data);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
break;
ret = -EIO;
break;
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 3) || addr < 0 ||
addr > sizeof(struct user) - 3)
break;
if (addr < FRAME_SIZE*sizeof(long)) {
ret = putreg(child, addr, data);
break;
}
/* We need to be very careful here. We implicitly
want to modify a portion of the task_struct, and we
have to be selective about what portions we allow someone
to modify. */
ret = -EIO;
if(addr >= (long) &dummy->u_debugreg[0] &&
addr <= (long) &dummy->u_debugreg[7]){
if(addr == (long) &dummy->u_debugreg[4]) break;
if(addr == (long) &dummy->u_debugreg[5]) break;
if(addr < (long) &dummy->u_debugreg[4] &&
((unsigned long) data) >= TASK_SIZE-3) break;
if(addr == (long) &dummy->u_debugreg[7]) {
data &= ~DR_CONTROL_RESERVED;
for(i=0; i<4; i++)
if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
goto out_tsk;
}
addr -= (long) &dummy->u_debugreg;
addr = addr >> 2;
child->thread.debugreg[addr] = data;
ret = 0;
}
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
long tmp;
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
if (request == PTRACE_SYSCALL)
child->ptrace |= PT_TRACESYS;
else
child->ptrace &= ~PT_TRACESYS;
child->exit_code = data;
/* make sure the single step bit is not set. */
tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
put_stack_long(child, EFL_OFFSET,tmp);
wake_up_process(child);
ret = 0;
break;
}
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL: {
long tmp;
ret = 0;
if (child->state == TASK_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
put_stack_long(child, EFL_OFFSET, tmp);
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
long tmp;
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
child->ptrace &= ~PT_TRACESYS;
if ((child->ptrace & PT_DTRACE) == 0) {
/* Spurious delayed TF traps may occur */
child->ptrace |= PT_DTRACE;
}
tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;
put_stack_long(child, EFL_OFFSET, tmp);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
}
case PTRACE_DETACH:
/* detach a process that was attached. */
ret = ptrace_detach(child, data);
break;
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
if (!access_ok(VERIFY_WRITE, (unsigned *)data, FRAME_SIZE*sizeof(long))) {
ret = -EIO;
break;
}
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
__put_user(getreg(child, i),(unsigned long *) data);
data += sizeof(long);
}
ret = 0;
break;
}
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
unsigned long tmp;
if (!access_ok(VERIFY_READ, (unsigned *)data, FRAME_SIZE*sizeof(long))) {
ret = -EIO;
break;
}
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
__get_user(tmp, (unsigned long *) data);
putreg(child, i, tmp);
data += sizeof(long);
}
ret = 0;
break;
}
case PTRACE_GETFPREGS: { /* Get the child FPU state. */
if (!access_ok(VERIFY_WRITE, (unsigned *)data,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
ret = 0;
if ( !child->used_math ) {
/* Simulate an empty FPU. */
set_fpu_cwd(child, 0x037f);
set_fpu_swd(child, 0x0000);
set_fpu_twd(child, 0xffff);
}
get_fpregs((struct user_i387_struct *)data, child);
break;
}
case PTRACE_SETFPREGS: { /* Set the child FPU state. */
if (!access_ok(VERIFY_READ, (unsigned *)data,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
child->used_math = 1;
set_fpregs(child, (struct user_i387_struct *)data);
ret = 0;
break;
}
case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
if (!access_ok(VERIFY_WRITE, (unsigned *)data,
sizeof(struct user_fxsr_struct))) {
ret = -EIO;
break;
}
if ( !child->used_math ) {
/* Simulate an empty FPU. */
set_fpu_cwd(child, 0x037f);
set_fpu_swd(child, 0x0000);
set_fpu_twd(child, 0xffff);
set_fpu_mxcsr(child, 0x1f80);
}
ret = get_fpxregs((struct user_fxsr_struct *)data, child);
break;
}
case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
if (!access_ok(VERIFY_READ, (unsigned *)data,
sizeof(struct user_fxsr_struct))) {
ret = -EIO;
break;
}
child->used_math = 1;
ret = set_fpxregs(child, (struct user_fxsr_struct *)data);
break;
}
case PTRACE_SETOPTIONS: {
if (data & PTRACE_O_TRACESYSGOOD)
child->ptrace |= PT_TRACESYSGOOD;
else
child->ptrace &= ~PT_TRACESYSGOOD;
ret = 0;
break;
}
default:
ret = -EIO;
break;
}
out_tsk:
free_task_struct(child);
out:
unlock_kernel();
return ret;
}
asmlinkage void syscall_trace(void)
{
if ((current->ptrace & (PT_PTRACED|PT_TRACESYS)) !=
(PT_PTRACED|PT_TRACESYS))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0);
current->state = TASK_STOPPED;
notify_parent(current, SIGCHLD);
schedule();
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
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