/* * linux/kernel/ptrace.c * * (C) Copyright 1999 Linus Torvalds * * Common interfaces for "ptrace()" which we do not want * to continually duplicate across every architecture. */#include <linux/sched.h>#include <linux/errno.h>#include <linux/mm.h>#include <linux/highmem.h>#include <linux/smp_lock.h>#include <asm/pgtable.h>#include <asm/uaccess.h>#include <asm/io.h> /* * Check that we have indeed attached to the thing.. */int ptrace_check_attach(struct task_struct *child, int kill){	if (!(child->ptrace & PT_PTRACED))		return -ESRCH;	if (child->p_pptr != current)		return -ESRCH;	if (!kill) {		if (child->state != TASK_STOPPED)			return -ESRCH;#ifdef CONFIG_SMP		wait_task_inactive(child);#endif			}	/* All systems go.. */	return 0;}int ptrace_attach(struct task_struct *task){	task_lock(task);	if (task->pid <= 1)		goto bad;	if (task == current)		goto bad;	if (!task->mm)		goto bad;	if(((current->uid != task->euid) ||	    (current->uid != task->suid) ||	    (current->uid != task->uid) || 	    (current->gid != task->egid) || 	    (current->gid != task->sgid) || 	    (!cap_issubset(task->cap_permitted, current->cap_permitted)) || 	    (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))		goto bad;	rmb();	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))		goto bad;	/* the same process cannot be attached many times */	if (task->ptrace & PT_PTRACED)		goto bad;	/* Go */	task->ptrace |= PT_PTRACED;	if (capable(CAP_SYS_PTRACE))		task->ptrace |= PT_PTRACE_CAP;	task_unlock(task);	write_lock_irq(&tasklist_lock);	if (task->p_pptr != current) {		REMOVE_LINKS(task);		task->p_pptr = current;		SET_LINKS(task);	}	write_unlock_irq(&tasklist_lock);	send_sig(SIGSTOP, task, 1);	return 0;bad:	task_unlock(task);	return -EPERM;}int ptrace_detach(struct task_struct *child, unsigned int data){	if ((unsigned long) data > _NSIG)		return	-EIO;	/* Architecture-specific hardware disable .. */	ptrace_disable(child);	/* .. re-parent .. */	child->ptrace = 0;	child->exit_code = data;	write_lock_irq(&tasklist_lock);	REMOVE_LINKS(child);	child->p_pptr = child->p_opptr;	SET_LINKS(child);	write_unlock_irq(&tasklist_lock);	/* .. and wake it up. */	wake_up_process(child);	return 0;}/* * Access another process' address space. * Source/target buffer must be kernel space,  * Do not walk the page table directly, use get_user_pages */int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write){	struct mm_struct *mm;	struct vm_area_struct *vma;	struct page *page;	void *old_buf = buf;	int xip_untouched = 0;	/* Worry about races with exit() */	task_lock(tsk);	mm = tsk->mm;	if (mm)		atomic_inc(&mm->mm_users);	task_unlock(tsk);	if (!mm)		return 0;	down_read(&mm->mmap_sem);	/* ignore errors, just check how much was sucessfully transfered */	while (len) {		int bytes, ret, offset;		void *maddr;#ifdef CONFIG_XIP_DEBUGGABLE 		extern int xip_enable_debug;		if (!write && xip_enable_debug) {			unsigned long physaddr;			extern int find_xip_untouched_entry(struct mm_struct *mm,							    unsigned long addr,							    unsigned long *physaddr);							ret = find_xip_untouched_entry(mm, addr, &physaddr);			if (ret) {				xip_untouched = 1;				maddr = ioremap(physaddr, PAGE_SIZE);				if (!maddr) 					break;	/* Need to check maddr. */ 				page = NULL;			}		}#endif				if (!xip_untouched) {			ret = get_user_pages(current, mm, addr, 1,								 write, 1, &page, &vma);			if (ret <= 0) 				break;		}		bytes = len;		offset = addr & (PAGE_SIZE-1);		if (bytes > PAGE_SIZE-offset)			bytes = PAGE_SIZE-offset;		if (!xip_untouched) {			flush_cache_page(vma, addr);			maddr = kmap(page);		}		if (write) {			memcpy(maddr + offset, buf, bytes);			if (!xip_untouched) {#ifdef CONFIG_SUPERH				flush_dcache_page(page);#endif				flush_page_to_ram(page);				flush_icache_user_range(vma, page, addr, len);			}		} else {			memcpy(buf, maddr + offset, bytes);			if (!xip_untouched)				flush_page_to_ram(page);		}		if (!xip_untouched) {			kunmap(page);			put_page(page);		} else { 			iounmap(maddr);		}		len -= bytes;		buf += bytes;		addr += bytes;	}	up_read(&mm->mmap_sem);	mmput(mm);		return buf - old_buf;}int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int len){	int copied = 0;	while (len > 0) {		char buf[128];		int this_len, retval;		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;		retval = access_process_vm(tsk, src, buf, this_len, 0);		if (!retval) {			if (copied)				break;			return -EIO;		}		if (copy_to_user(dst, buf, retval))			return -EFAULT;		copied += retval;		src += retval;		dst += retval;		len -= retval;				}	return copied;}int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int len){	int copied = 0;	while (len > 0) {		char buf[128];		int this_len, retval;		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;		if (copy_from_user(buf, src, this_len))			return -EFAULT;		retval = access_process_vm(tsk, dst, buf, this_len, 1);		if (!retval) {			if (copied)				break;			return -EIO;		}		copied += retval;		src += retval;		dst += retval;		len -= retval;				}	return copied;}static int ptrace_setoptions(struct task_struct *child, long data){	if (data & PTRACE_O_TRACESYSGOOD)		child->ptrace |= PT_TRACESYSGOOD;	else		child->ptrace &= ~PT_TRACESYSGOOD;	if (data & PTRACE_O_TRACEFORK)		child->ptrace |= PT_TRACE_FORK;	else		child->ptrace &= ~PT_TRACE_FORK;	if (data & PTRACE_O_TRACEVFORK)		child->ptrace |= PT_TRACE_VFORK;	else		child->ptrace &= ~PT_TRACE_VFORK;	if (data & PTRACE_O_TRACECLONE)		child->ptrace |= PT_TRACE_CLONE;	else		child->ptrace &= ~PT_TRACE_CLONE;	if (data & PTRACE_O_TRACEEXEC)		child->ptrace |= PT_TRACE_EXEC;	else		child->ptrace &= ~PT_TRACE_EXEC;	if ((data & (PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEFORK		    | PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE		    | PTRACE_O_TRACEEXEC))	    != data)		return -EINVAL;	return 0;}int ptrace_request(struct task_struct *child, long request,		   long addr, long data){	int ret = -EIO;	switch (request) {#ifdef PTRACE_OLDSETOPTIONS	case PTRACE_OLDSETOPTIONS:#endif	case PTRACE_SETOPTIONS:		ret = ptrace_setoptions(child, data);		break;	case PTRACE_GETEVENTMSG:		ret = put_user(child->ptrace_message, (unsigned long *) data);		break;	default:		break;	}	return ret;}void ptrace_notify(int exit_code){	if (!(current->ptrace & PT_PTRACED)) BUG ();	/* Let the debugger run.  */	current->exit_code = exit_code;	set_current_state(TASK_STOPPED);	notify_parent(current, SIGCHLD);	schedule();}