arch/um/kernel/ptrace.c - linux - Git at Google

 /*
  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */

 #include "linux/audit.h"
 #include "linux/ptrace.h"
 #include "linux/sched.h"
 #include "asm/uaccess.h"
 #ifdef CONFIG_PROC_MM
 #include "proc_mm.h"
 #endif
 #include "skas_ptrace.h"

 static inline void set_singlestepping(struct task_struct *child, int on)
 {
 	if (on)
 		child->ptrace |= PT_DTRACE;
 	else
 		child->ptrace &= ~PT_DTRACE;
 	child->thread.singlestep_syscall = 0;

 #ifdef SUBARCH_SET_SINGLESTEPPING
 	SUBARCH_SET_SINGLESTEPPING(child, on);
 #endif
 }

 /*
  * Called by kernel/ptrace.c when detaching..
  */
 void ptrace_disable(struct task_struct *child)
 {
 	set_singlestepping(child,0);
 }

 extern int peek_user(struct task_struct * child, long addr, long data);
 extern int poke_user(struct task_struct * child, long addr, long data);

 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
 	int i, ret;
 	unsigned long __user *p = (void __user *)(unsigned long)data;

 	switch (request) {
 	/* read word at location addr. */
 	case PTRACE_PEEKTEXT:
 	case PTRACE_PEEKDATA:
 		ret = generic_ptrace_peekdata(child, addr, data);
 		break;

 	/* read the word at location addr in the USER area. */
 	case PTRACE_PEEKUSR:
 		ret = peek_user(child, addr, data);
 		break;

 	/* write the word at location addr. */
 	case PTRACE_POKETEXT:
 	case PTRACE_POKEDATA:
 		ret = generic_ptrace_pokedata(child, addr, data);
 		break;

 	/* write the word at location addr in the USER area */
 	case PTRACE_POKEUSR:
 		ret = poke_user(child, addr, data);
 		break;

 	case PTRACE_SYSEMU:
 	case PTRACE_SYSEMU_SINGLESTEP:
 		ret = -EIO;
 		break;

 	/* continue and stop at next (return from) syscall */
 	case PTRACE_SYSCALL:
 	/* restart after signal. */
 	case PTRACE_CONT: {
 		ret = -EIO;
 		if (!valid_signal(data))
 			break;

 		set_singlestepping(child, 0);
 		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;
 		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;

 		set_singlestepping(child, 0);
 		child->exit_code = SIGKILL;
 		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_TRACE);
 		set_singlestepping(child, 1);
 		child->exit_code = data;
 		/* give it a chance to run. */
 		wake_up_process(child);
 		ret = 0;
 		break;
 	}

 #ifdef PTRACE_GETREGS
 	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 			ret = -EIO;
 			break;
 		}
 		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 			__put_user(getreg(child, i), p);
 			p++;
 		}
 		ret = 0;
 		break;
 	}
 #endif
 #ifdef PTRACE_SETREGS
 	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 		unsigned long tmp = 0;
 		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 			ret = -EIO;
 			break;
 		}
 		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 			__get_user(tmp, p);
 			putreg(child, i, tmp);
 			p++;
 		}
 		ret = 0;
 		break;
 	}
 #endif
 #ifdef PTRACE_GETFPREGS
 	case PTRACE_GETFPREGS: /* Get the child FPU state. */
 		ret = get_fpregs((struct user_i387_struct __user *) data,
 				 child);
 		break;
 #endif
 #ifdef PTRACE_SETFPREGS
 	case PTRACE_SETFPREGS: /* Set the child FPU state. */
 	        ret = set_fpregs((struct user_i387_struct __user *) data,
 				 child);
 		break;
 #endif
 	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;

 	case PTRACE_FAULTINFO: {
 		/*
 		 * Take the info from thread->arch->faultinfo,
 		 * but transfer max. sizeof(struct ptrace_faultinfo).
 		 * On i386, ptrace_faultinfo is smaller!
 		 */
 		ret = copy_to_user(p, &child->thread.arch.faultinfo,
 				   sizeof(struct ptrace_faultinfo));
 		break;
 	}

 #ifdef PTRACE_LDT
 	case PTRACE_LDT: {
 		struct ptrace_ldt ldt;

 		if (copy_from_user(&ldt, p, sizeof(ldt))) {
 			ret = -EIO;
 			break;
 		}

 		/*
 		 * This one is confusing, so just punt and return -EIO for
 		 * now
 		 */
 		ret = -EIO;
 		break;
 	}
 #endif
 #ifdef CONFIG_PROC_MM
 	case PTRACE_SWITCH_MM: {
 		struct mm_struct *old = child->mm;
 		struct mm_struct *new = proc_mm_get_mm(data);

 		if (IS_ERR(new)) {
 			ret = PTR_ERR(new);
 			break;
 		}

 		atomic_inc(&new->mm_users);
 		child->mm = new;
 		child->active_mm = new;
 		mmput(old);
 		ret = 0;
 		break;
 	}
 #endif
 #ifdef PTRACE_ARCH_PRCTL
 	case PTRACE_ARCH_PRCTL:
 		/* XXX Calls ptrace on the host - needs some SMP thinking */
 		ret = arch_prctl(child, data, (void *) addr);
 		break;
 #endif
 	default:
 		ret = ptrace_request(child, request, addr, data);
 		if (ret == -EIO)
 			ret = subarch_ptrace(child, request, addr, data);
 		break;
 	}

 	return ret;
 }

 static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 		  int error_code)
 {
 	struct siginfo info;

 	memset(&info, 0, sizeof(info));
 	info.si_signo = SIGTRAP;
 	info.si_code = TRAP_BRKPT;

 	/* User-mode eip? */
 	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;

 	/* Send us the fake SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }

 /*
  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
  */
 void syscall_trace(struct uml_pt_regs *regs, int entryexit)
 {
 	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 	int tracesysgood;

 	if (unlikely(current->audit_context)) {
 		if (!entryexit)
 			audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
 		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 					UPT_SYSCALL_RET(regs));
 	}

 	/* Fake a debug trap */
 	if (is_singlestep)
 		send_sigtrap(current, regs, 0);

 	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
 	 */
 	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));

 	if (entryexit) /* force do_signal() --> is_syscall() */
 		set_thread_flag(TIF_SIGPENDING);

 	/*
 	 * 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;
 	}
 }
	/*
	* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
	* Licensed under the GPL
	*/

	#include "linux/audit.h"
	#include "linux/ptrace.h"
	#include "linux/sched.h"
	#include "asm/uaccess.h"
	#ifdef CONFIG_PROC_MM
	#include "proc_mm.h"
	#endif
	#include "skas_ptrace.h"

	static inline void set_singlestepping(struct task_struct *child, int on)
	{
	if (on)
	child->ptrace \|= PT_DTRACE;
	else
	child->ptrace &= ~PT_DTRACE;
	child->thread.singlestep_syscall = 0;

	#ifdef SUBARCH_SET_SINGLESTEPPING
	SUBARCH_SET_SINGLESTEPPING(child, on);
	#endif
	}

	/*
	* Called by kernel/ptrace.c when detaching..
	*/
	void ptrace_disable(struct task_struct *child)
	{
	set_singlestepping(child,0);
	}

	extern int peek_user(struct task_struct * child, long addr, long data);
	extern int poke_user(struct task_struct * child, long addr, long data);

	long arch_ptrace(struct task_struct *child, long request, long addr, long data)
	{
	int i, ret;
	unsigned long __user p = (void __user )(unsigned long)data;

	switch (request) {
	/* read word at location addr. */
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
	ret = generic_ptrace_peekdata(child, addr, data);
	break;

	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR:
	ret = peek_user(child, addr, data);
	break;

	/* write the word at location addr. */
	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
	ret = generic_ptrace_pokedata(child, addr, data);
	break;

	/* write the word at location addr in the USER area */
	case PTRACE_POKEUSR:
	ret = poke_user(child, addr, data);
	break;

	case PTRACE_SYSEMU:
	case PTRACE_SYSEMU_SINGLESTEP:
	ret = -EIO;
	break;

	/* continue and stop at next (return from) syscall */
	case PTRACE_SYSCALL:
	/* restart after signal. */
	case PTRACE_CONT: {
	ret = -EIO;
	if (!valid_signal(data))
	break;

	set_singlestepping(child, 0);
	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;
	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;

	set_singlestepping(child, 0);
	child->exit_code = SIGKILL;
	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_TRACE);
	set_singlestepping(child, 1);
	child->exit_code = data;
	/* give it a chance to run. */
	wake_up_process(child);
	ret = 0;
	break;
	}

	#ifdef PTRACE_GETREGS
	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
	if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
	ret = -EIO;
	break;
	}
	for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
	__put_user(getreg(child, i), p);
	p++;
	}
	ret = 0;
	break;
	}
	#endif
	#ifdef PTRACE_SETREGS
	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
	unsigned long tmp = 0;
	if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
	ret = -EIO;
	break;
	}
	for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
	__get_user(tmp, p);
	putreg(child, i, tmp);
	p++;
	}
	ret = 0;
	break;
	}
	#endif
	#ifdef PTRACE_GETFPREGS
	case PTRACE_GETFPREGS: /* Get the child FPU state. */
	ret = get_fpregs((struct user_i387_struct __user *) data,
	child);
	break;
	#endif
	#ifdef PTRACE_SETFPREGS
	case PTRACE_SETFPREGS: /* Set the child FPU state. */
	ret = set_fpregs((struct user_i387_struct __user *) data,
	child);
	break;
	#endif
	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;

	case PTRACE_FAULTINFO: {
	/*
	* Take the info from thread->arch->faultinfo,
	* but transfer max. sizeof(struct ptrace_faultinfo).
	* On i386, ptrace_faultinfo is smaller!
	*/
	ret = copy_to_user(p, &child->thread.arch.faultinfo,
	sizeof(struct ptrace_faultinfo));
	break;
	}

	#ifdef PTRACE_LDT
	case PTRACE_LDT: {
	struct ptrace_ldt ldt;

	if (copy_from_user(&ldt, p, sizeof(ldt))) {
	ret = -EIO;
	break;
	}

	/*
	* This one is confusing, so just punt and return -EIO for
	* now
	*/
	ret = -EIO;
	break;
	}
	#endif
	#ifdef CONFIG_PROC_MM
	case PTRACE_SWITCH_MM: {
	struct mm_struct *old = child->mm;
	struct mm_struct *new = proc_mm_get_mm(data);

	if (IS_ERR(new)) {
	ret = PTR_ERR(new);
	break;
	}

	atomic_inc(&new->mm_users);
	child->mm = new;
	child->active_mm = new;
	mmput(old);
	ret = 0;
	break;
	}
	#endif
	#ifdef PTRACE_ARCH_PRCTL
	case PTRACE_ARCH_PRCTL:
	/* XXX Calls ptrace on the host - needs some SMP thinking */
	ret = arch_prctl(child, data, (void *) addr);
	break;
	#endif
	default:
	ret = ptrace_request(child, request, addr, data);
	if (ret == -EIO)
	ret = subarch_ptrace(child, request, addr, data);
	break;
	}

	return ret;
	}

	static void send_sigtrap(struct task_struct tsk, struct uml_pt_regs regs,
	int error_code)
	{
	struct siginfo info;

	memset(&info, 0, sizeof(info));
	info.si_signo = SIGTRAP;
	info.si_code = TRAP_BRKPT;

	/* User-mode eip? */
	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;

	/* Send us the fake SIGTRAP */
	force_sig_info(SIGTRAP, &info, tsk);
	}

	/*
	* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
	* PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
	*/
	void syscall_trace(struct uml_pt_regs *regs, int entryexit)
	{
	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
	int tracesysgood;

	if (unlikely(current->audit_context)) {
	if (!entryexit)
	audit_syscall_entry(HOST_AUDIT_ARCH,
	UPT_SYSCALL_NR(regs),
	UPT_SYSCALL_ARG1(regs),
	UPT_SYSCALL_ARG2(regs),
	UPT_SYSCALL_ARG3(regs),
	UPT_SYSCALL_ARG4(regs));
	else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
	UPT_SYSCALL_RET(regs));
	}

	/* Fake a debug trap */
	if (is_singlestep)
	send_sigtrap(current, regs, 0);

	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
	*/
	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
	ptrace_notify(SIGTRAP \| (tracesysgood ? 0x80 : 0));

	if (entryexit) /* force do_signal() --> is_syscall() */
	set_thread_flag(TIF_SIGPENDING);

	/*
	* 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;
	}
	}