/*
 * 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"
#include "skas_ptrace.h"



void user_enable_single_step(struct task_struct *child)
{
        child->ptrace |= PT_DTRACE;
        child->thread.singlestep_syscall = 0;

#ifdef SUBARCH_SET_SINGLESTEPPING
        SUBARCH_SET_SINGLESTEPPING(child, 1);
#endif
}

void user_disable_single_step(struct task_struct *child)
{
        child->ptrace &= ~PT_DTRACE;
        child->thread.singlestep_syscall = 0;

#ifdef SUBARCH_SET_SINGLESTEPPING
        SUBARCH_SET_SINGLESTEPPING(child, 0);
#endif
}

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

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,
                 unsigned long addr, unsigned long data)
{
        int i, ret;
        unsigned long __user *p = (void __user *)data;
        void __user *vp = p;

        switch (request) {
        /* 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 in the USER area */
        case PTRACE_POKEUSR:
                ret = poke_user(child, addr, data);
                break;

        case PTRACE_SYSEMU:
        case PTRACE_SYSEMU_SINGLESTEP:
                ret = -EIO;
                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
        case PTRACE_GET_THREAD_AREA:
                ret = ptrace_get_thread_area(child, addr, vp);
                break;

        case PTRACE_SET_THREAD_AREA:
                ret = ptrace_set_thread_area(child, addr, vp);
                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)) ?
                        -EIO : 0;
                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
        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 (!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(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;
        }
}