clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 
 if (request == PTRACE_SYSEMU_SINGLESTEP) set_tsk_thread_flag(child, TIF_SYSCALL_EMU); else clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);  
asmlinkage int sys_ptrace(long request, long pid, long addr, long data){	struct task_struct *child;	struct user * dummy = NULL;	int i, ret;	unsigned long __user *datap = (unsigned long __user *)data;	lock_kernel();	ret = -EPERM;	if (request == PTRACE_TRACEME) {		/* are we already being traced? */		if (current->ptrace & PT_PTRACED)			goto out;		ret = security_ptrace(current->parent, current);		if (ret)			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, datap);		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, datap);		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;			  			  /* Sanity-check data. Take one half-byte at once with			   * check = (val >> (16 + 4*i)) & 0xf. It contains the			   * R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits			   * 2 and 3 are LENi. Given a list of invalid values,			   * we do mask |= 1 << invalid_value, so that			   * (mask >> check) & 1 is a correct test for invalid			   * values.			   *			   * R/Wi contains the type of the breakpoint /			   * watchpoint, LENi contains the length of the watched			   * data in the watchpoint case.			   *			   * The invalid values are:			   * - LENi == 0x10 (undefined), so mask |= 0x0f00.			   * - R/Wi == 0x10 (break on I/O reads or writes), so			   *   mask |= 0x4444.			   * - R/Wi == 0x00 && LENi != 0x00, so we have mask |=			   *   0x1110.			   *			   * Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.			   *			   * See the Intel Manual "System Programming Guide",			   * 15.2.4			   *			   * Note that LENi == 0x10 is defined on x86_64 in long			   * mode (i.e. even for 32-bit userspace software, but			   * 64-bit kernel), so the x86_64 mask value is 0x5454.			   * See the AMD manual no. 24593 (AMD64 System			   * Programming)*/			  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_SYSEMU: /* continue and stop at next syscall, which will not be executed */	case PTRACE_SYSCALL:	/* continue and stop at next (return from) syscall */	case PTRACE_CONT:	/* restart after signal. */		ret = -EIO;		if (!valid_signal(data))			break;		if (request == PTRACE_SYSEMU) {			set_tsk_thread_flag(child, TIF_SYSCALL_EMU);			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);		} else if (request == PTRACE_SYSCALL) {			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);			clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);		} else {			clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);		}		child->exit_code = data;		/* make sure the single step bit is not set. */		clear_singlestep(child);		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:		ret = 0;		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */			break;		child->exit_code = SIGKILL;		/* make sure the single step bit is not set. */		clear_singlestep(child);		wake_up_process(child);		break;	case PTRACE_SINGLESTEP:	/* set the trap flag. */		ret = -EIO;		if (!valid_signal(data))			break;		clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);		set_singlestep(child);		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, datap, FRAME_SIZE*sizeof(long))) {			ret = -EIO;			break;		}		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {			__put_user(getreg(child, i), datap);			datap++;		}		ret = 0;		break;	}	case PTRACE_SETREGS: { /* Set all gp regs in the child. */		unsigned long tmp;	  	if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {			ret = -EIO;			break;		}		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {			__get_user(tmp, datap);			putreg(child, i, tmp);			datap++;		}		ret = 0;		break;	}	case PTRACE_GETFPREGS: { /* Get the child FPU state. */		if (!access_ok(VERIFY_WRITE, datap,			       sizeof(struct user_i387_struct))) {			ret = -EIO;			break;		}		ret = 0;		if (!tsk_used_math(child))			init_fpu(child);		get_fpregs((struct user_i387_struct __user *)data, child);		break;	}	case PTRACE_SETFPREGS: { /* Set the child FPU state. */		if (!access_ok(VERIFY_READ, datap,			       sizeof(struct user_i387_struct))) {			ret = -EIO;			break;		}		set_stopped_child_used_math(child);		set_fpregs(child, (struct user_i387_struct __user *)data);		ret = 0;		break;	}	case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */		if (!access_ok(VERIFY_WRITE, datap,			       sizeof(struct user_fxsr_struct))) {			ret = -EIO;			break;		}		if (!tsk_used_math(child))			init_fpu(child);		ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);		break;	}	case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */		if (!access_ok(VERIFY_READ, datap,			       sizeof(struct user_fxsr_struct))) {			ret = -EIO;			break;		}		set_stopped_child_used_math(child);		ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);		break;	}	case PTRACE_GET_THREAD_AREA:		ret = ptrace_get_thread_area(child, addr,					(struct user_desc __user *) data);		break;	case PTRACE_SET_THREAD_AREA:		ret = ptrace_set_thread_area(child, addr,					(struct user_desc __user *) data);		break;	default:		ret = ptrace_request(child, request, addr, data);		break;	}out_tsk:	put_task_struct(child);out:	unlock_kernel();	return ret;}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/1b38f0064e4e0b9ec626e39f0740b1cf2e295743/ptrace.c/clean/arch/i386/kernel/ptrace.c