linux-imx

/*

 * 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/capability.h>

#include <linux/export.h>

#include <linux/sched.h>

#include <linux/sched/mm.h>

#include <linux/sched/coredump.h>

#include <linux/sched/task.h>

#include <linux/errno.h>

#include <linux/mm.h>

#include <linux/highmem.h>

#include <linux/pagemap.h>

#include <linux/ptrace.h>

#include <linux/security.h>

#include <linux/signal.h>

#include <linux/uio.h>

#include <linux/audit.h>

#include <linux/pid_namespace.h>

#include <linux/syscalls.h>

#include <linux/uaccess.h>

#include <linux/regset.h>

#include <linux/hw_breakpoint.h>

#include <linux/cn_proc.h>

#include <linux/compat.h>

#include <linux/sched/signal.h>

​

/*

 * Access another process' address space via ptrace.

 * Source/target buffer must be kernel space,

 * Do not walk the page table directly, use get_user_pages

 */

int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,

             void *buf, int len, unsigned int gup_flags)

{

    struct mm_struct *mm;

    int ret;

​

    mm = get_task_mm(tsk);

    if (!mm)

        return 0;

​

    if (!tsk->ptrace ||

        (current != tsk->parent) ||

        ((get_dumpable(mm) != SUID_DUMP_USER) &&

         !ptracer_capable(tsk, mm->user_ns))) {

        mmput(mm);

        return 0;

    }

​

    ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);

    mmput(mm);

​

    return ret;

}

​

​

void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,

           const struct cred *ptracer_cred)

{

    BUG_ON(!list_empty(&child->ptrace_entry));

    list_add(&child->ptrace_entry, &new_parent->ptraced);

    child->parent = new_parent;

    child->ptracer_cred = get_cred(ptracer_cred);

}

​

/*

 * ptrace a task: make the debugger its new parent and

 * move it to the ptrace list.

 *

 * Must be called with the tasklist lock write-held.

 */

static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)

{

    rcu_read_lock();

    __ptrace_link(child, new_parent, __task_cred(new_parent));

    rcu_read_unlock();

}

​

/**

 * __ptrace_unlink - unlink ptracee and restore its execution state

 * @child: ptracee to be unlinked

 *

 * Remove @child from the ptrace list, move it back to the original parent,

 * and restore the execution state so that it conforms to the group stop

 * state.