Sindbad~EG File Manager

// task information tapset
// Copyright (C) 2006 Intel Corporation.
// Copyright (C) 2010-2017 Red Hat Inc.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

%{
#include <linux/version.h>
#include <linux/file.h>
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,25)
#include <linux/fdtable.h>
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0)
#include <linux/sched/rt.h>
#endif
#ifndef STAPCONF_TASK_UID
#include <linux/cred.h>
#endif
#include <linux/fs_struct.h>
#include <linux/mm.h>
%}

/**
 * sfunction task_current - The current task_struct of the current task
 *
 * Description: This function returns the task_struct representing the current process.
 * This address can be passed to the various task_*() functions to extract
 * more task-specific data.
 */
function task_current:long () {
    return & @task(%{ /* pure */ (unsigned long)current %})
}

@__private30 function _task_rlimit_cur:long (task:long, nd_limit:long)
{
    if (nd_limit < 0 || nd_limit >= @const("RLIM_NLIMITS")) {
        return -1;
    }
    sig = @task(task)->signal;
    return @cast(sig, "signal_struct", "kernel")->rlim[nd_limit]->rlim_cur;
}

/* sfunction task_rlimit - The current resource limit of the task
 *
 * @task: task_struct pointer
 * @lim_str: String representing limit.
 *
 * Description: Little bit slower way how ger resource limits of
 * process.
 * There is need translate string into number for each call.
 */
function task_rlimit:long (task:long, lim_str:string)
{
    lim = rlimit_from_str(lim_str);
    if (lim == -1) { return -1; }
    return _task_rlimit_cur(task, lim);
}

/* Fast and "safe" way how to do it. */

function task_rlimit_cpu:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_CPU") );
}

function task_rlimit_fsize:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_FSIZE"));
}

function task_rlimit_data:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_DATA"));
}

function task_rlimit_stack:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_STACK"));
}

function task_rlimit_core:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_CORE"));
}

function task_rlimit_rss:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_RSS"));
}

function task_rlimit_nproc:long (task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_NPROC"));
}

function task_rlimit_nofile:long(task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_NOFILE"));
}

function task_rlimit_memlock:long(task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_MEMLOCK"));
}

function task_rlimit_as:long(task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_AS"));
}

function task_rlimit_locks:long(task:long)
{
    return _task_rlimit_cur(task, @const("RLIMIT_LOCKS"));
}

function task_rlimit_sigpending:long(task:long)
{
    %( kernel_v >= "2.6.8" %?
        return _task_rlimit_cur(task, @const("RLIMIT_SIGPENDING"));
    %:
        return -1
    %)
}

function task_rlimit_msgqueue:long(task:long)
{
    %( kernel_v >= "2.6.8" %?
        return _task_rlimit_cur(task, @const("RLIMIT_MSGQUEUE"));
    %:
        return -1
    %)
}

function task_rlimit_nice:long(task:long)
{
    %( kernel_v >= "2.6.12" %?
        return _task_rlimit_cur(task, @const("RLIMIT_NICE"));
    %:
        return -1
    %)
}

function task_rlimit_rtprio:long(task:long)
{
    %( kernel_v >= "2.6.12" %?
        return _task_rlimit_cur(task, @const("RLIMIT_RTPRIO"));
    %:
        return -1
    %)
}

function task_rlimit_rttime:long(task:long)
{
    %( kernel_v >= "2.6.25" %?
        return _task_rlimit_cur(task, @const("RLIMIT_RTTIME"));
    %:
        return -1
    %)
}

/**
 * sfunction task_parent - The task_struct of the parent task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the parent task_struct of
 * the given task. This address can be passed to the various 
 * task_*() functions to extract more task-specific data.
 */
function task_parent:long(task:long)
{
    return @choose_defined(@task(task)->real_parent, @task(task)->parent)
}

/**
 * sfunction task_state - The state of the task
 *
 * @task: task_struct pointer
 *
 * Description: Return the state of the given task, one of:
 * TASK_RUNNING (0), TASK_INTERRUPTIBLE (1), TASK_UNINTERRUPTIBLE (2),
 * TASK_STOPPED (4), TASK_TRACED (8), EXIT_ZOMBIE (16), or EXIT_DEAD (32).
 */
function task_state:long (task:long)
{
  return @choose_defined(@task(task)->state,@task(task)->__state)
}

/**
 * sfunction task_execname - The name of the task
 *
 * @task: task_struct pointer
 *
 * Description: Return the name of the given task.
 */
function task_execname:string (task:long)
{
    return kernel_string(@task(task)->comm)
}

/**
 * sfunction task_pid - The process identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This fucntion returns the process id of the given task.
 */
function task_pid:long (task:long)
{
    return @task(task)->tgid
}

/**
 * sfunction task_ns_pid - The process identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This fucntion returns the process id of the given task based on
 * the specified pid namespace..
 */
function task_ns_pid:long (task:long) %{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_pid_ns(t, PID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}

/**
 * sfunction pid2task - The task_struct of the given process identifier
 *
 * @pid: process identifier
 *
 * Description: Return the task struct of the given process id.
 */
function pid2task:long (pid:long) {
    return & @task(%{ /* pure */ ({
        struct task_struct *t = NULL;
        pid_t t_pid  = (pid_t)(long)STAP_ARG_pid;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,31)
        struct pid *p_pid = find_get_pid(t_pid);
        rcu_read_lock();
        t = pid_task(p_pid, PIDTYPE_PID);
        put_pid(p_pid);
#else
        rcu_read_lock();
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
        t = find_task_by_vpid (t_pid);
#else
        t = find_task_by_pid (t_pid);
#endif /* 2.6.24 */
#endif /* 2.6.31 */
        rcu_read_unlock();
        (unsigned long)t;
    }) %})
}

/**
 * sfunction pid2execname - The name of the given process identifier
 *
 * @pid: process identifier
 *
 * Description: Return the name of the given process id.
 */
function pid2execname:string (pid:long) { 
    tsk = pid2task(pid)
    if (tsk)
	return task_execname(tsk)
    return ""
}

/**
 * sfunction task_tid - The thread identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the thread id of the given task.
 */
function task_tid:long (task:long)
{
    return @task(task)->pid
}

/**
 * sfunction task_ns_tid - The thread identifier of the task as seen in a namespace
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the thread id of the given task as seen 
 * in the pid namespace.
 */
function task_ns_tid:long (task:long)%{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_pid_ns(t, TID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_gid - The group identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the group id of the given task.
 */
function task_gid:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#ifdef STAPCONF_TASK_UID
    STAP_RETVALUE = kread(&(t->gid));
#else
#ifdef STAPCONF_FROM_KUID_MUNGED
    struct user_namespace *user_ns;
#endif

    /* We can't easily kread the task_struct's rcu-protected
     * credential fields. So, let's just make sure the entire
     * task_struct is valid to read. */
    (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

    /* If task_gid() isn't defined, make our own. */
#if !defined(task_gid) && defined(task_cred_xxx)
#define task_gid(task)		(task_cred_xxx((task), gid))
#endif

#ifdef STAPCONF_FROM_KUID_MUNGED
    /* We also need to validate the namespace structure. */
    user_ns = task_cred_xxx(t, user_ns);
    (void)kderef_buffer(NULL, user_ns, sizeof(struct user_namespace));
    STAP_RETVALUE = from_kgid_munged(user_ns, task_gid(t));
#else
    STAP_RETVALUE = task_gid (t);
#endif
#endif
    CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_ns_gid - The group identifier of the task as seen in a namespace
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the group id of the given task as seen in
 * in the given user namespace.
*/
function task_ns_gid:long (task:long) %{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_user_ns(t, GID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_egid - The effective group identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the effective group id of the given task.
 */
function task_egid:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#ifdef STAPCONF_TASK_UID
    STAP_RETVALUE = kread(&(t->egid));
#else
#ifdef STAPCONF_FROM_KUID_MUNGED
    struct user_namespace *user_ns;
#endif

    /* We can't easily kread the task_struct's rcu-protected
     * credential fields. So, let's just make sure the entire
     * task_struct is valid to read. */
    (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

    /* If task_egid() isn't defined, make our own. */
#if !defined(task_egid) && defined(task_cred_xxx)
#define task_egid(task)		(task_cred_xxx((task), egid))
#endif

#ifdef STAPCONF_FROM_KUID_MUNGED
    /* We also need to validate the namespace structure. */
    user_ns = task_cred_xxx(t, user_ns);
    (void)kderef_buffer(NULL, user_ns, sizeof(struct user_namespace));
    STAP_RETVALUE = from_kgid_munged(user_ns, task_egid(t));
#else
    STAP_RETVALUE = task_egid (t);
#endif
#endif
    CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_ns_egid - The effective group identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the effective group id of the given task.
 */
function task_ns_egid:long (task:long) %{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_user_ns(current, EGID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_uid - The user identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the user id of the given task.
 */
function task_uid:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#ifdef STAPCONF_TASK_UID
    STAP_RETVALUE = kread(&(t->uid));
#else
#ifdef STAPCONF_FROM_KUID_MUNGED
    struct user_namespace *user_ns;
#endif

    /* We can't easily kread the task_struct's rcu-protected
     * credential fields. So, let's just make sure the entire
     * task_struct is valid to read. */
    (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

#ifdef STAPCONF_FROM_KUID_MUNGED
    /* We also need to validate the namespace structure. */
    user_ns = task_cred_xxx(t, user_ns);
    (void)kderef_buffer(NULL, user_ns, sizeof(struct user_namespace));
    STAP_RETVALUE = from_kuid_munged(user_ns, task_uid(t));
#else
    STAP_RETVALUE = task_uid (t);
#endif
#endif
    CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_ns_uid - The user identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the user id of the given task.
 */
function task_ns_uid:long (task:long) %{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_user_ns(current, UID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_euid - The effective user identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the effective user id of the given task.
 */
function task_euid:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#ifdef STAPCONF_TASK_UID
    STAP_RETVALUE = kread(&(t->euid));
#else
#ifdef STAPCONF_FROM_KUID_MUNGED
    struct user_namespace *user_ns;
#endif

    /* We can't easily kread the task_struct's rcu-protected
     * credential fields. So, let's just make sure the entire
     * task_struct is valid to read. */
    (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

#ifdef STAPCONF_FROM_KUID_MUNGED
    /* We also need to validate the namespace structure. */
    user_ns = task_cred_xxx(t, user_ns);
    (void)kderef_buffer(NULL, user_ns, sizeof(struct user_namespace));
    STAP_RETVALUE = from_kuid_munged(user_ns, task_euid(t));
#else
    STAP_RETVALUE = task_euid (t);
#endif
#endif
    CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_ns_euid - The effective user identifier of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the effective user id of the given task.
 */
function task_ns_euid:long (task:long) %{ /* pure */ /* guru */
  struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
  int64_t rc;

  /* Before using the task_struct pointer, make sure it is valid to
   * read. */
  (void)kderef_buffer(NULL, t, sizeof(struct task_struct));

  rc = from_target_user_ns(current, EUID);
  if (rc < 0)
    STAP_ERROR ("cannot resolve id in namespace");
  else
    STAP_RETURN (rc);
  CATCH_DEREF_FAULT();
%}


/**
 * sfunction task_prio - The priority value of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the priority value of the given task.
 */
function task_prio:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
    STAP_RETVALUE =  kread(&(t->prio)) - MAX_RT_PRIO;
    CATCH_DEREF_FAULT();
%}


/**
 * sfunction task_nice - The nice value of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the nice value of the given task.
 */
function task_nice:long (task:long) %{ /* pure */
    struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
    STAP_RETVALUE = kread(&(t->static_prio)) - MAX_RT_PRIO - 20;
    CATCH_DEREF_FAULT();
%}

/**
 * sfunction task_cpu - The scheduled cpu of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the scheduled cpu for the given task.
 */
function task_cpu:long (task:long)
{
  if (@defined(@task(task)->cpu))
      return @task(task)->cpu
  else
      {
        ti = @choose_defined(@task(task)->stack, @task(task)->thread_info);
        return @cast(ti, "thread_info", "kernel<linux/sched.h>")->cpu
      }
}

/**
 * sfunction task_open_file_handles - The number of open files of the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the number of open file handlers for the given task.
 */
function task_open_file_handles:long (task:long)
%{ /* pure */
    int locked = 0;
    unsigned int count=0, fd, max;
    struct task_struct *t;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
    /* Older kernels */
    struct files_struct *f;
#else
    struct files_struct *fs;
    struct fdtable *f;
#endif
    t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
    /* Older kernels */
    f = kread(&(t->files));
#else
    fs = kread(&(t->files));
    f = kread(&(fs->fdt));
#endif
    rcu_read_lock();
    locked = 1;
    max = kread(&(f->max_fds));
    for (fd = 0; fd < max; fd++) {
                if ( kread(&(f->fd[fd])) != NULL)
                        count ++;
        }
    STAP_RETVALUE = count;
    CATCH_DEREF_FAULT();
    if (locked)
        rcu_read_unlock();
%}

/**
 * sfunction task_max_file_handles - The max number of open files for the task
 *
 * @task: task_struct pointer
 *
 * Description: This function returns the maximum number of file handlers for the given task.
 */
function task_max_file_handles:long (task:long)
%{ /* pure */
    int locked = 0;
    struct task_struct *t;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
    struct files_struct *f;
#else
    struct files_struct *fs;
    struct fdtable *f;
#endif
    t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
    f = kread(&(t->files));
#else
    fs = kread (&(t->files));
    f = kread(&(fs->fdt));
#endif
    rcu_read_lock();
    locked = 1;
    STAP_RETVALUE = kread(&(f->max_fds));
    CATCH_DEREF_FAULT();
    if (locked)
        rcu_read_unlock();
%}

/**
 *   sfunction task_fd_lookup - get the file struct for a task's fd
 *
 *   @task: task_struct pointer.
 *   @fd: file descriptor number.
 *
 *   Description: Returns the file struct pointer for a task's file
 *   descriptor.
 */
function task_fd_lookup:long(task:long, fd:long)
%{ /* pure */
	struct task_struct *t = (struct task_struct *)(uintptr_t)STAP_ARG_task;
	struct files_struct *files = NULL;
	unsigned int fd = (unsigned int)(unsigned long)STAP_ARG_fd;
	struct file *file = NULL;
    
	/* Before using the task_struct pointer, make sure it is valid
	 * to read.
	 *
	 * Note that originally we called
	 * get_task_struct()/put_task_struct() here. However, just
	 * because the task_struct memory is valid to read, doesn't
	 * mean it is valid to *write* to this memory, which
	 * get_task_struct() does. So, we won't bother with
	 * get_task_struct()/put_task_struct(). */
	(void)kderef_buffer(NULL, t, sizeof(struct task_struct));

	// We should be calling get_files_struct() here, but it isn't
	// exported. This means that we can't lock the
	// files_struct.
	files = t->files;
	if (files) {
		/* Before using the files_struct pointer, make sure it is
		 * valid to read. */
		(void)kderef_buffer(NULL, files, sizeof(struct files_struct));

		spin_lock(&files->file_lock);
#ifdef STAPCONF_FILES_LOOKUP_FD_RAW
		file = files_lookup_fd_raw(files, fd);
#else
		file = fcheck_files(files, fd);
#endif
		spin_unlock(&files->file_lock);
	}

	if (file) {
		// Note that we're returning a pointer which isn't
		// locked or has had its usage count increased. There
		// is nothing keeping this pointer valid until we use
		// it. So, before using it, it must be validated by
		// callers.
		STAP_RETURN((unsigned long)file);
	}
	else {
		STAP_ERROR ("cannot find file in task");
	}
	
	CATCH_DEREF_FAULT();
%}

/**
 *   sfunction task_cwd_path - get the path struct pointer for a task's current working directory
 *
 *   @task: task_struct pointer.
 */
function task_cwd_path:long(task:long)
%{ /* pure */
	struct task_struct *task
		= (struct task_struct *)(uintptr_t)STAP_ARG_task;
	int put_task_struct_needed = 0;

	// Before using the task_struct pointer, make sure it is valid
	// to read.
	(void)kderef_buffer(NULL, task, sizeof(struct task_struct));

	// OK, we now know it is valid to read. But, is it really a
	// task struct?
	if (!_stp_task_struct_valid(task)) {
		STAP_ERROR ("invalid task struct pointer");
	}

	get_task_struct(task);
	put_task_struct_needed = 1;

	// The kernel calls get_fs_pwd() here, which is an inlined
	// function in include/linux/fs_struct.h. This function
	// doesn't return a path pointer, but assumes the caller has
	// allocated storage for the struct path. Instead, we're going
	// to return a pointer to task->fs->pwd.
	if (task->fs) {
		// Sigh. On kernels before 2.6.25, the task->fs->pwd
		// structure exists, but isn't a 'path'
		// structure. Instead it is a 'dentry' structure. The
		// 'pwd' and 'pwdmnt' (which is a 'vfsmount'
		// structure) variables would both be needed to get a
		// pathname. However, this function can't return 2
		// items or really declare a static 'path' structure
		// to put the 2 pointers in.
		//
		// So, on those RHEL5-era kernels, we'll just return
		// NULL here.
#ifdef STAPCONF_DPATH_PATH
		// Before using the task->fs pointer, let's be
		// paranoid and make sure it is valid to read.
		(void)kderef_buffer(NULL, task->fs, sizeof(struct fs_struct));
		if (put_task_struct_needed)
			put_task_struct(task);
		STAP_RETURN((unsigned long)&task->fs->pwd);
#endif
	}
	CATCH_DEREF_FAULT();
	if (put_task_struct_needed)
		put_task_struct(task);
%}

/**
 *   sfunction current_exe_file - get the file struct pointer for the current task's executable file
 *
 * Description: This function returns the file struct pointer for the
 * current task's executable file. Note that the file struct pointer
 * isn't locked on return. The return value of this function can be
 * passed to fullpath_struct_file() to get the path from the file
 * struct.
 */
function current_exe_file:long()
%{ /* pure */
	struct file *exe_file = NULL;

	if (current == NULL) {
		STAP_ERROR ("No current task");
	}

	// Since we're stopped inside current, it isn't going away. So
	// don't bother incrementing the task's usage count by calling
	// get_task_struct()/put_task_struct(). We also don't need to
	// bother to try to lock current->mm.
	if (current->mm) {
		exe_file = stap_find_exe_file(current->mm);
		if (exe_file) {
			STAP_RETVALUE = (unsigned long)exe_file;
			fput(exe_file);
		}
	}
%}

%(systemtap_v <= "3.2" %?
/**
 *   sfunction task_exe_file - get the file struct pointer for a task's executable file
 *
 *   @task: task_struct pointer.
 */
function task_exe_file:long(task:long)
{
	if (task == task_current()) {
		return current_exe_file()
	}
	error("Only the exe file for the current task can be returned")
}
%)