arch/ppc64/kernel/ptrace.c - third_party/linux - Git at Google

 /*
  *  linux/arch/ppc64/kernel/ptrace.c
  *
  *  PowerPC version
  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  *
  *  Derived from "arch/m68k/kernel/ptrace.c"
  *  Copyright (C) 1994 by Hamish Macdonald
  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  *
  * Modified by Cort Dougan (cort@hq.fsmlabs.com)
  * and Paul Mackerras (paulus@linuxcare.com.au).
  *
  * This file is subject to the terms and conditions of the GNU General
  * Public License.  See the file README.legal in the main directory of
  * this archive for more details.
  */

 #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 <linux/security.h>
 #include <linux/audit.h>
 #include <linux/seccomp.h>

 #include <asm/uaccess.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/ptrace-common.h>

 /*
  * does not yet catch signals sent when the child dies.
  * in exit.c or in signal.c.
  */

 /*
  * Called by kernel/ptrace.c when detaching..
  *
  * Make sure single step bits etc are not set.
  */
 void ptrace_disable(struct task_struct *child)
 {
 	/* make sure the single step bit is not set. */
 	clear_single_step(child);
 }

 int sys_ptrace(long request, long pid, long addr, long data)
 {
 	struct task_struct *child;
 	int ret = -EPERM;

 	lock_kernel();
 	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,(unsigned long __user *) data);
 		break;
 	}

 	/* read the word at location addr in the USER area. */
 	case PTRACE_PEEKUSR: {
 		unsigned long index;
 		unsigned long tmp;

 		ret = -EIO;
 		/* convert to index and check */
 		index = (unsigned long) addr >> 3;
 		if ((addr & 7) || (index > PT_FPSCR))
 			break;

 		if (index < PT_FPR0) {
 			tmp = get_reg(child, (int)index);
 		} else {
 			flush_fp_to_thread(child);
 			tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 		}
 		ret = put_user(tmp,(unsigned long __user *) data);
 		break;
 	}

 	/* If 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;

 	/* write the word at location addr in the USER area */
 	case PTRACE_POKEUSR: {
 		unsigned long index;

 		ret = -EIO;
 		/* convert to index and check */
 		index = (unsigned long) addr >> 3;
 		if ((addr & 7) || (index > PT_FPSCR))
 			break;

 		if (index == PT_ORIG_R3)
 			break;
 		if (index < PT_FPR0) {
 			ret = put_reg(child, index, data);
 		} else {
 			flush_fp_to_thread(child);
 			((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 			ret = 0;
 		}
 		break;
 	}

 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 	case PTRACE_CONT: { /* restart after signal. */
 		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;
 		/* make sure the single step bit is not set. */
 		clear_single_step(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_single_step(child);
 		wake_up_process(child);
 		break;
 	}

 	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 		ret = -EIO;
 		if ((unsigned long) data > _NSIG)
 			break;
 		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		set_single_step(child);
 		child->exit_code = data;
 		/* give it a chance to run. */
 		wake_up_process(child);
 		ret = 0;
 		break;
 	}

 	case PTRACE_DETACH:
 		ret = ptrace_detach(child, data);
 		break;

 	case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 		int i;
 		unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 		unsigned long __user *tmp = (unsigned long __user *)addr;

 		for (i = 0; i < 32; i++) {
 			ret = put_user(*reg, tmp);
 			if (ret)
 				break;
 			reg++;
 			tmp++;
 		}
 		break;
 	}

 	case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 		int i;
 		unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 		unsigned long __user *tmp = (unsigned long __user *)addr;

 		for (i = 0; i < 32; i++) {
 			ret = get_user(*reg, tmp);
 			if (ret)
 				break;
 			reg++;
 			tmp++;
 		}
 		break;
 	}

 	case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 		int i;
 		unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 		unsigned long __user *tmp = (unsigned long __user *)addr;

 		flush_fp_to_thread(child);

 		for (i = 0; i < 32; i++) {
 			ret = put_user(*reg, tmp);
 			if (ret)
 				break;
 			reg++;
 			tmp++;
 		}
 		break;
 	}

 	case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 		int i;
 		unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 		unsigned long __user *tmp = (unsigned long __user *)addr;

 		flush_fp_to_thread(child);

 		for (i = 0; i < 32; i++) {
 			ret = get_user(*reg, tmp);
 			if (ret)
 				break;
 			reg++;
 			tmp++;
 		}
 		break;
 	}

 	default:
 		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
 	put_task_struct(child);
 out:
 	unlock_kernel();
 	return ret;
 }

 static void do_syscall_trace(void)
 {
 	/* 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.  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;
 	}
 }

 void do_syscall_trace_enter(struct pt_regs *regs)
 {
 	if (unlikely(current->audit_context))
 		audit_syscall_entry(current, regs->gpr[0],
 				    regs->gpr[3], regs->gpr[4],
 				    regs->gpr[5], regs->gpr[6]);

 	if (test_thread_flag(TIF_SYSCALL_TRACE)
 	    && (current->ptrace & PT_PTRACED))
 		do_syscall_trace();
 }

 void do_syscall_trace_leave(struct pt_regs *regs)
 {
 	secure_computing(regs->gpr[0]);

 	if (unlikely(current->audit_context))
 		audit_syscall_exit(current, regs->result);

 	if ((test_thread_flag(TIF_SYSCALL_TRACE)
 	     || test_thread_flag(TIF_SINGLESTEP))
 	    && (current->ptrace & PT_PTRACED))
 		do_syscall_trace();
 }
	/*
	* linux/arch/ppc64/kernel/ptrace.c
	*
	* PowerPC version
	* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
	*
	* Derived from "arch/m68k/kernel/ptrace.c"
	* Copyright (C) 1994 by Hamish Macdonald
	* Taken from linux/kernel/ptrace.c and modified for M680x0.
	* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
	*
	* Modified by Cort Dougan (cort@hq.fsmlabs.com)
	* and Paul Mackerras (paulus@linuxcare.com.au).
	*
	* This file is subject to the terms and conditions of the GNU General
	* Public License. See the file README.legal in the main directory of
	* this archive for more details.
	*/

	#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 <linux/security.h>
	#include <linux/audit.h>
	#include <linux/seccomp.h>

	#include <asm/uaccess.h>
	#include <asm/page.h>
	#include <asm/pgtable.h>
	#include <asm/system.h>
	#include <asm/ptrace-common.h>

	/*
	* does not yet catch signals sent when the child dies.
	* in exit.c or in signal.c.
	*/

	/*
	* Called by kernel/ptrace.c when detaching..
	*
	* Make sure single step bits etc are not set.
	*/
	void ptrace_disable(struct task_struct *child)
	{
	/* make sure the single step bit is not set. */
	clear_single_step(child);
	}

	int sys_ptrace(long request, long pid, long addr, long data)
	{
	struct task_struct *child;
	int ret = -EPERM;

	lock_kernel();
	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,(unsigned long __user *) data);
	break;
	}

	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR: {
	unsigned long index;
	unsigned long tmp;

	ret = -EIO;
	/* convert to index and check */
	index = (unsigned long) addr >> 3;
	if ((addr & 7) \|\| (index > PT_FPSCR))
	break;

	if (index < PT_FPR0) {
	tmp = get_reg(child, (int)index);
	} else {
	flush_fp_to_thread(child);
	tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
	}
	ret = put_user(tmp,(unsigned long __user *) data);
	break;
	}

	/* If 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;

	/* write the word at location addr in the USER area */
	case PTRACE_POKEUSR: {
	unsigned long index;

	ret = -EIO;
	/* convert to index and check */
	index = (unsigned long) addr >> 3;
	if ((addr & 7) \|\| (index > PT_FPSCR))
	break;

	if (index == PT_ORIG_R3)
	break;
	if (index < PT_FPR0) {
	ret = put_reg(child, index, data);
	} else {
	flush_fp_to_thread(child);
	((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
	ret = 0;
	}
	break;
	}

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
	case PTRACE_CONT: { /* restart after signal. */
	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;
	/* make sure the single step bit is not set. */
	clear_single_step(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_single_step(child);
	wake_up_process(child);
	break;
	}

	case PTRACE_SINGLESTEP: { /* set the trap flag. */
	ret = -EIO;
	if ((unsigned long) data > _NSIG)
	break;
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	set_single_step(child);
	child->exit_code = data;
	/* give it a chance to run. */
	wake_up_process(child);
	ret = 0;
	break;
	}

	case PTRACE_DETACH:
	ret = ptrace_detach(child, data);
	break;

	case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
	int i;
	unsigned long reg = &((unsigned long )child->thread.regs)[0];
	unsigned long __user tmp = (unsigned long __user )addr;

	for (i = 0; i < 32; i++) {
	ret = put_user(*reg, tmp);
	if (ret)
	break;
	reg++;
	tmp++;
	}
	break;
	}

	case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
	int i;
	unsigned long reg = &((unsigned long )child->thread.regs)[0];
	unsigned long __user tmp = (unsigned long __user )addr;

	for (i = 0; i < 32; i++) {
	ret = get_user(*reg, tmp);
	if (ret)
	break;
	reg++;
	tmp++;
	}
	break;
	}

	case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
	int i;
	unsigned long reg = &((unsigned long )child->thread.fpr)[0];
	unsigned long __user tmp = (unsigned long __user )addr;

	flush_fp_to_thread(child);

	for (i = 0; i < 32; i++) {
	ret = put_user(*reg, tmp);
	if (ret)
	break;
	reg++;
	tmp++;
	}
	break;
	}

	case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
	int i;
	unsigned long reg = &((unsigned long )child->thread.fpr)[0];
	unsigned long __user tmp = (unsigned long __user )addr;

	flush_fp_to_thread(child);

	for (i = 0; i < 32; i++) {
	ret = get_user(*reg, tmp);
	if (ret)
	break;
	reg++;
	tmp++;
	}
	break;
	}

	default:
	ret = ptrace_request(child, request, addr, data);
	break;
	}
	out_tsk:
	put_task_struct(child);
	out:
	unlock_kernel();
	return ret;
	}

	static void do_syscall_trace(void)
	{
	/* 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. 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;
	}
	}

	void do_syscall_trace_enter(struct pt_regs *regs)
	{
	if (unlikely(current->audit_context))
	audit_syscall_entry(current, regs->gpr[0],
	regs->gpr[3], regs->gpr[4],
	regs->gpr[5], regs->gpr[6]);

	if (test_thread_flag(TIF_SYSCALL_TRACE)
	&& (current->ptrace & PT_PTRACED))
	do_syscall_trace();
	}

	void do_syscall_trace_leave(struct pt_regs *regs)
	{
	secure_computing(regs->gpr[0]);

	if (unlikely(current->audit_context))
	audit_syscall_exit(current, regs->result);

	if ((test_thread_flag(TIF_SYSCALL_TRACE)
	\|\| test_thread_flag(TIF_SINGLESTEP))
	&& (current->ptrace & PT_PTRACED))
	do_syscall_trace();
	}