321 lines
6.5 KiB
C
321 lines
6.5 KiB
C
/*
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* Copyright (C) 2000-2003, Axis Communications AB.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/errno.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/signal.h>
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#include <linux/security.h>
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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/*
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* Determines which bits in DCCR the user has access to.
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* 1 = access, 0 = no access.
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*/
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#define DCCR_MASK 0x0000001f /* XNZVC */
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/*
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* Get contents of register REGNO in task TASK.
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*/
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inline long get_reg(struct task_struct *task, unsigned int regno)
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{
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/* USP is a special case, it's not in the pt_regs struct but
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* in the tasks thread struct
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*/
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if (regno == PT_USP)
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return task->thread.usp;
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else if (regno < PT_MAX)
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return ((unsigned long *)user_regs(task->thread_info))[regno];
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else
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return 0;
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}
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/*
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* Write contents of register REGNO in task TASK.
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*/
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inline int put_reg(struct task_struct *task, unsigned int regno,
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unsigned long data)
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{
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if (regno == PT_USP)
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task->thread.usp = data;
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else if (regno < PT_MAX)
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((unsigned long *)user_regs(task->thread_info))[regno] = data;
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else
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return -1;
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return 0;
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}
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/*
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* Called by kernel/ptrace.c when detaching.
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*
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* Make sure the single step bit is not set.
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*/
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void
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ptrace_disable(struct task_struct *child)
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{
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/* Todo - pending singlesteps? */
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}
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/*
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* Note that this implementation of ptrace behaves differently from vanilla
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* ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
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* PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
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* ignored. Instead, the data variable is expected to point at a location
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* (in user space) where the result of the ptrace call is written (instead of
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* being returned).
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*/
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asmlinkage int
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sys_ptrace(long request, long pid, long addr, long data)
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{
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struct task_struct *child;
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int ret;
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unsigned long __user *datap = (unsigned long __user *)data;
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lock_kernel();
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ret = -EPERM;
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if (request == PTRACE_TRACEME) {
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/* are we already being traced? */
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if (current->ptrace & PT_PTRACED)
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goto out;
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ret = security_ptrace(current->parent, current);
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if (ret)
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goto out;
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/* set the ptrace bit in the process flags. */
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current->ptrace |= PT_PTRACED;
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ret = 0;
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goto out;
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}
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ret = -ESRCH;
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read_lock(&tasklist_lock);
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child = find_task_by_pid(pid);
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if (child)
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get_task_struct(child);
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read_unlock(&tasklist_lock);
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if (!child)
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goto out;
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ret = -EPERM;
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if (pid == 1) /* Leave the init process alone! */
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goto out_tsk;
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if (request == PTRACE_ATTACH) {
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ret = ptrace_attach(child);
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goto out_tsk;
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}
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ret = ptrace_check_attach(child, request == PTRACE_KILL);
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if (ret < 0)
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goto out_tsk;
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switch (request) {
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/* Read word at location address. */
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case PTRACE_PEEKTEXT:
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case PTRACE_PEEKDATA: {
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unsigned long tmp;
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int copied;
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copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
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ret = -EIO;
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if (copied != sizeof(tmp))
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break;
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ret = put_user(tmp,datap);
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break;
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}
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/* Read the word at location address in the USER area. */
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case PTRACE_PEEKUSR: {
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unsigned long tmp;
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ret = -EIO;
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if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
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break;
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tmp = get_reg(child, addr >> 2);
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ret = put_user(tmp, datap);
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break;
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}
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/* Write the word at location address. */
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case PTRACE_POKETEXT:
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case PTRACE_POKEDATA:
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ret = 0;
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if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
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break;
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ret = -EIO;
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break;
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/* Write the word at location address in the USER area. */
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case PTRACE_POKEUSR:
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ret = -EIO;
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if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
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break;
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addr >>= 2;
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if (addr == PT_DCCR) {
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/* don't allow the tracing process to change stuff like
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* interrupt enable, kernel/user bit, dma enables etc.
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*/
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data &= DCCR_MASK;
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data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
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}
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if (put_reg(child, addr, data))
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break;
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ret = 0;
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break;
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case PTRACE_SYSCALL:
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case PTRACE_CONT:
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ret = -EIO;
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if (!valid_signal(data))
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break;
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if (request == PTRACE_SYSCALL) {
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set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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}
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else {
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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}
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child->exit_code = data;
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/* TODO: make sure any pending breakpoint is killed */
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wake_up_process(child);
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ret = 0;
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break;
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/* Make the child exit by sending it a sigkill. */
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case PTRACE_KILL:
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ret = 0;
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if (child->exit_state == EXIT_ZOMBIE)
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break;
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child->exit_code = SIGKILL;
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/* TODO: make sure any pending breakpoint is killed */
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wake_up_process(child);
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break;
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/* Set the trap flag. */
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case PTRACE_SINGLESTEP:
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ret = -EIO;
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if (!valid_signal(data))
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break;
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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/* TODO: set some clever breakpoint mechanism... */
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child->exit_code = data;
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wake_up_process(child);
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ret = 0;
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break;
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case PTRACE_DETACH:
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ret = ptrace_detach(child, data);
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break;
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/* Get all GP registers from the child. */
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case PTRACE_GETREGS: {
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int i;
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unsigned long tmp;
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for (i = 0; i <= PT_MAX; i++) {
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tmp = get_reg(child, i);
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if (put_user(tmp, datap)) {
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ret = -EFAULT;
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goto out_tsk;
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}
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data += sizeof(long);
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}
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ret = 0;
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break;
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}
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/* Set all GP registers in the child. */
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case PTRACE_SETREGS: {
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int i;
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unsigned long tmp;
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for (i = 0; i <= PT_MAX; i++) {
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if (get_user(tmp, datap)) {
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ret = -EFAULT;
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goto out_tsk;
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}
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if (i == PT_DCCR) {
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tmp &= DCCR_MASK;
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tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
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}
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put_reg(child, i, tmp);
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data += sizeof(long);
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}
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ret = 0;
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break;
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}
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default:
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ret = ptrace_request(child, request, addr, data);
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break;
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}
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out_tsk:
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put_task_struct(child);
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out:
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unlock_kernel();
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return ret;
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}
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void do_syscall_trace(void)
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{
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if (!test_thread_flag(TIF_SYSCALL_TRACE))
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return;
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if (!(current->ptrace & PT_PTRACED))
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return;
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/* the 0x80 provides a way for the tracing parent to distinguish
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between a syscall stop and SIGTRAP delivery */
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ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
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? 0x80 : 0));
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/*
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* This isn't the same as continuing with a signal, but it will do for
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* normal use.
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*/
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if (current->exit_code) {
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send_sig(current->exit_code, current, 1);
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current->exit_code = 0;
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}
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}
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