Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
389
kernel/ptrace.c
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389
kernel/ptrace.c
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/*
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* linux/kernel/ptrace.c
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*
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* (C) Copyright 1999 Linus Torvalds
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*
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* Common interfaces for "ptrace()" which we do not want
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* to continually duplicate across every architecture.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include <linux/ptrace.h>
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#include <linux/security.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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/*
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* ptrace a task: make the debugger its new parent and
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* move it to the ptrace list.
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*
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* Must be called with the tasklist lock write-held.
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*/
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void __ptrace_link(task_t *child, task_t *new_parent)
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{
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if (!list_empty(&child->ptrace_list))
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BUG();
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if (child->parent == new_parent)
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return;
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list_add(&child->ptrace_list, &child->parent->ptrace_children);
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REMOVE_LINKS(child);
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child->parent = new_parent;
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SET_LINKS(child);
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}
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/*
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* Turn a tracing stop into a normal stop now, since with no tracer there
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* would be no way to wake it up with SIGCONT or SIGKILL. If there was a
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* signal sent that would resume the child, but didn't because it was in
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* TASK_TRACED, resume it now.
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* Requires that irqs be disabled.
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*/
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void ptrace_untrace(task_t *child)
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{
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spin_lock(&child->sighand->siglock);
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if (child->state == TASK_TRACED) {
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if (child->signal->flags & SIGNAL_STOP_STOPPED) {
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child->state = TASK_STOPPED;
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} else {
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signal_wake_up(child, 1);
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}
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}
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spin_unlock(&child->sighand->siglock);
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}
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/*
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* unptrace a task: move it back to its original parent and
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* remove it from the ptrace list.
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*
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* Must be called with the tasklist lock write-held.
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*/
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void __ptrace_unlink(task_t *child)
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{
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if (!child->ptrace)
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BUG();
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child->ptrace = 0;
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if (!list_empty(&child->ptrace_list)) {
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list_del_init(&child->ptrace_list);
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REMOVE_LINKS(child);
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child->parent = child->real_parent;
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SET_LINKS(child);
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}
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if (child->state == TASK_TRACED)
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ptrace_untrace(child);
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}
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/*
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* Check that we have indeed attached to the thing..
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*/
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int ptrace_check_attach(struct task_struct *child, int kill)
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{
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int ret = -ESRCH;
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/*
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* We take the read lock around doing both checks to close a
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* possible race where someone else was tracing our child and
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* detached between these two checks. After this locked check,
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* we are sure that this is our traced child and that can only
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* be changed by us so it's not changing right after this.
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*/
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read_lock(&tasklist_lock);
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if ((child->ptrace & PT_PTRACED) && child->parent == current &&
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(!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
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&& child->signal != NULL) {
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ret = 0;
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spin_lock_irq(&child->sighand->siglock);
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if (child->state == TASK_STOPPED) {
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child->state = TASK_TRACED;
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} else if (child->state != TASK_TRACED && !kill) {
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ret = -ESRCH;
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}
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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if (!ret && !kill) {
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wait_task_inactive(child);
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}
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/* All systems go.. */
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return ret;
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}
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int ptrace_attach(struct task_struct *task)
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{
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int retval;
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task_lock(task);
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retval = -EPERM;
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if (task->pid <= 1)
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goto bad;
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if (task == current)
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goto bad;
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if (!task->mm)
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goto bad;
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if(((current->uid != task->euid) ||
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(current->uid != task->suid) ||
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(current->uid != task->uid) ||
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(current->gid != task->egid) ||
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(current->gid != task->sgid) ||
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(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
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goto bad;
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rmb();
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if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
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goto bad;
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/* the same process cannot be attached many times */
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if (task->ptrace & PT_PTRACED)
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goto bad;
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retval = security_ptrace(current, task);
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if (retval)
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goto bad;
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/* Go */
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task->ptrace |= PT_PTRACED | ((task->real_parent != current)
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? PT_ATTACHED : 0);
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if (capable(CAP_SYS_PTRACE))
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task->ptrace |= PT_PTRACE_CAP;
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task_unlock(task);
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write_lock_irq(&tasklist_lock);
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__ptrace_link(task, current);
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write_unlock_irq(&tasklist_lock);
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force_sig_specific(SIGSTOP, task);
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return 0;
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bad:
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task_unlock(task);
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return retval;
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}
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int ptrace_detach(struct task_struct *child, unsigned int data)
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{
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if ((unsigned long) data > _NSIG)
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return -EIO;
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/* Architecture-specific hardware disable .. */
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ptrace_disable(child);
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/* .. re-parent .. */
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child->exit_code = data;
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write_lock_irq(&tasklist_lock);
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__ptrace_unlink(child);
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/* .. and wake it up. */
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if (child->exit_state != EXIT_ZOMBIE)
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wake_up_process(child);
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write_unlock_irq(&tasklist_lock);
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return 0;
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}
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/*
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* Access another process' address space.
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* Source/target buffer must be kernel space,
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* Do not walk the page table directly, use get_user_pages
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*/
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int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
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{
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struct mm_struct *mm;
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struct vm_area_struct *vma;
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struct page *page;
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void *old_buf = buf;
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mm = get_task_mm(tsk);
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if (!mm)
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return 0;
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down_read(&mm->mmap_sem);
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/* ignore errors, just check how much was sucessfully transfered */
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while (len) {
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int bytes, ret, offset;
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void *maddr;
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ret = get_user_pages(tsk, mm, addr, 1,
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write, 1, &page, &vma);
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if (ret <= 0)
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break;
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bytes = len;
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offset = addr & (PAGE_SIZE-1);
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if (bytes > PAGE_SIZE-offset)
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bytes = PAGE_SIZE-offset;
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maddr = kmap(page);
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if (write) {
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copy_to_user_page(vma, page, addr,
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maddr + offset, buf, bytes);
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set_page_dirty_lock(page);
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} else {
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copy_from_user_page(vma, page, addr,
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buf, maddr + offset, bytes);
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}
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kunmap(page);
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page_cache_release(page);
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len -= bytes;
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buf += bytes;
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addr += bytes;
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}
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up_read(&mm->mmap_sem);
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mmput(mm);
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return buf - old_buf;
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}
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int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
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{
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int copied = 0;
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while (len > 0) {
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char buf[128];
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int this_len, retval;
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this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
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retval = access_process_vm(tsk, src, buf, this_len, 0);
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if (!retval) {
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if (copied)
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break;
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return -EIO;
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}
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if (copy_to_user(dst, buf, retval))
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return -EFAULT;
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copied += retval;
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src += retval;
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dst += retval;
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len -= retval;
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}
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return copied;
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}
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int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
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{
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int copied = 0;
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while (len > 0) {
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char buf[128];
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int this_len, retval;
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this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
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if (copy_from_user(buf, src, this_len))
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return -EFAULT;
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retval = access_process_vm(tsk, dst, buf, this_len, 1);
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if (!retval) {
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if (copied)
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break;
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return -EIO;
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}
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copied += retval;
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src += retval;
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dst += retval;
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len -= retval;
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}
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return copied;
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}
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static int ptrace_setoptions(struct task_struct *child, long data)
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{
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child->ptrace &= ~PT_TRACE_MASK;
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if (data & PTRACE_O_TRACESYSGOOD)
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child->ptrace |= PT_TRACESYSGOOD;
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if (data & PTRACE_O_TRACEFORK)
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child->ptrace |= PT_TRACE_FORK;
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if (data & PTRACE_O_TRACEVFORK)
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child->ptrace |= PT_TRACE_VFORK;
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if (data & PTRACE_O_TRACECLONE)
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child->ptrace |= PT_TRACE_CLONE;
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if (data & PTRACE_O_TRACEEXEC)
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child->ptrace |= PT_TRACE_EXEC;
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if (data & PTRACE_O_TRACEVFORKDONE)
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child->ptrace |= PT_TRACE_VFORK_DONE;
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if (data & PTRACE_O_TRACEEXIT)
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child->ptrace |= PT_TRACE_EXIT;
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return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
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}
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static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)
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{
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siginfo_t lastinfo;
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int error = -ESRCH;
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read_lock(&tasklist_lock);
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if (likely(child->sighand != NULL)) {
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error = -EINVAL;
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spin_lock_irq(&child->sighand->siglock);
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if (likely(child->last_siginfo != NULL)) {
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lastinfo = *child->last_siginfo;
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error = 0;
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}
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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if (!error)
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return copy_siginfo_to_user(data, &lastinfo);
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return error;
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}
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static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
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{
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siginfo_t newinfo;
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int error = -ESRCH;
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if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
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return -EFAULT;
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read_lock(&tasklist_lock);
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if (likely(child->sighand != NULL)) {
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error = -EINVAL;
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spin_lock_irq(&child->sighand->siglock);
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if (likely(child->last_siginfo != NULL)) {
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*child->last_siginfo = newinfo;
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error = 0;
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}
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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return error;
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}
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int ptrace_request(struct task_struct *child, long request,
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long addr, long data)
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{
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int ret = -EIO;
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switch (request) {
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#ifdef PTRACE_OLDSETOPTIONS
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case PTRACE_OLDSETOPTIONS:
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#endif
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case PTRACE_SETOPTIONS:
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ret = ptrace_setoptions(child, data);
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break;
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case PTRACE_GETEVENTMSG:
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ret = put_user(child->ptrace_message, (unsigned long __user *) data);
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break;
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case PTRACE_GETSIGINFO:
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ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
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break;
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case PTRACE_SETSIGINFO:
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ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
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break;
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default:
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break;
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}
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return ret;
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}
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