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