base.c 56.4 KB
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/*
 *  linux/fs/proc/base.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  proc base directory handling functions
 *
 *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
 *  Instead of using magical inumbers to determine the kind of object
 *  we allocate and fill in-core inodes upon lookup. They don't even
 *  go into icache. We cache the reference to task_struct upon lookup too.
 *  Eventually it should become a filesystem in its own. We don't use the
 *  rest of procfs anymore.
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 *
 *
 *  Changelog:
 *  17-Jan-2005
 *  Allan Bezerra
 *  Bruna Moreira <bruna.moreira@indt.org.br>
 *  Edjard Mota <edjard.mota@indt.org.br>
 *  Ilias Biris <ilias.biris@indt.org.br>
 *  Mauricio Lin <mauricio.lin@indt.org.br>
 *
 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
 *
 *  A new process specific entry (smaps) included in /proc. It shows the
 *  size of rss for each memory area. The maps entry lacks information
 *  about physical memory size (rss) for each mapped file, i.e.,
 *  rss information for executables and library files.
 *  This additional information is useful for any tools that need to know
 *  about physical memory consumption for a process specific library.
 *
 *  Changelog:
 *  21-Feb-2005
 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
 *  Pud inclusion in the page table walking.
 *
 *  ChangeLog:
 *  10-Mar-2005
 *  10LE Instituto Nokia de Tecnologia - INdT:
 *  A better way to walks through the page table as suggested by Hugh Dickins.
 *
 *  Simo Piiroinen <simo.piiroinen@nokia.com>:
 *  Smaps information related to shared, private, clean and dirty pages.
 *
 *  Paul Mundt <paul.mundt@nokia.com>:
 *  Overall revision about smaps.
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 */

#include <asm/uaccess.h>

#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
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#include <linux/capability.h>
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#include <linux/file.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/namei.h>
#include <linux/namespace.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
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#include <linux/rcupdate.h>
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#include <linux/kallsyms.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/seccomp.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
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#include <linux/poll.h>
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#include "internal.h"

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/* NOTE:
 *	Implementing inode permission operations in /proc is almost
 *	certainly an error.  Permission checks need to happen during
 *	each system call not at open time.  The reason is that most of
 *	what we wish to check for permissions in /proc varies at runtime.
 *
 *	The classic example of a problem is opening file descriptors
 *	in /proc for a task before it execs a suid executable.
 */

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/*
 * For hysterical raisins we keep the same inumbers as in the old procfs.
 * Feel free to change the macro below - just keep the range distinct from
 * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
 * As soon as we'll get a separate superblock we will be able to forget
 * about magical ranges too.
 */

#define fake_ino(pid,ino) (((pid)<<16)|(ino))

enum pid_directory_inos {
	PROC_TGID_INO = 2,
	PROC_TGID_TASK,
	PROC_TGID_STATUS,
	PROC_TGID_MEM,
#ifdef CONFIG_SECCOMP
	PROC_TGID_SECCOMP,
#endif
	PROC_TGID_CWD,
	PROC_TGID_ROOT,
	PROC_TGID_EXE,
	PROC_TGID_FD,
	PROC_TGID_ENVIRON,
	PROC_TGID_AUXV,
	PROC_TGID_CMDLINE,
	PROC_TGID_STAT,
	PROC_TGID_STATM,
	PROC_TGID_MAPS,
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	PROC_TGID_NUMA_MAPS,
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	PROC_TGID_MOUNTS,
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	PROC_TGID_MOUNTSTATS,
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	PROC_TGID_WCHAN,
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#ifdef CONFIG_MMU
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	PROC_TGID_SMAPS,
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#endif
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#ifdef CONFIG_SCHEDSTATS
	PROC_TGID_SCHEDSTAT,
#endif
#ifdef CONFIG_CPUSETS
	PROC_TGID_CPUSET,
#endif
#ifdef CONFIG_SECURITY
	PROC_TGID_ATTR,
	PROC_TGID_ATTR_CURRENT,
	PROC_TGID_ATTR_PREV,
	PROC_TGID_ATTR_EXEC,
	PROC_TGID_ATTR_FSCREATE,
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	PROC_TGID_ATTR_KEYCREATE,
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	PROC_TGID_ATTR_SOCKCREATE,
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#endif
#ifdef CONFIG_AUDITSYSCALL
	PROC_TGID_LOGINUID,
#endif
	PROC_TGID_OOM_SCORE,
	PROC_TGID_OOM_ADJUST,
	PROC_TID_INO,
	PROC_TID_STATUS,
	PROC_TID_MEM,
#ifdef CONFIG_SECCOMP
	PROC_TID_SECCOMP,
#endif
	PROC_TID_CWD,
	PROC_TID_ROOT,
	PROC_TID_EXE,
	PROC_TID_FD,
	PROC_TID_ENVIRON,
	PROC_TID_AUXV,
	PROC_TID_CMDLINE,
	PROC_TID_STAT,
	PROC_TID_STATM,
	PROC_TID_MAPS,
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	PROC_TID_NUMA_MAPS,
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	PROC_TID_MOUNTS,
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	PROC_TID_MOUNTSTATS,
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	PROC_TID_WCHAN,
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#ifdef CONFIG_MMU
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	PROC_TID_SMAPS,
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#endif
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#ifdef CONFIG_SCHEDSTATS
	PROC_TID_SCHEDSTAT,
#endif
#ifdef CONFIG_CPUSETS
	PROC_TID_CPUSET,
#endif
#ifdef CONFIG_SECURITY
	PROC_TID_ATTR,
	PROC_TID_ATTR_CURRENT,
	PROC_TID_ATTR_PREV,
	PROC_TID_ATTR_EXEC,
	PROC_TID_ATTR_FSCREATE,
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	PROC_TID_ATTR_KEYCREATE,
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	PROC_TID_ATTR_SOCKCREATE,
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#endif
#ifdef CONFIG_AUDITSYSCALL
	PROC_TID_LOGINUID,
#endif
	PROC_TID_OOM_SCORE,
	PROC_TID_OOM_ADJUST,
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	/* Add new entries before this */
	PROC_TID_FD_DIR = 0x8000,	/* 0x8000-0xffff */
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};

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/* Worst case buffer size needed for holding an integer. */
#define PROC_NUMBUF 10

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struct pid_entry {
	int type;
	int len;
	char *name;
	mode_t mode;
};

#define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}

static struct pid_entry tgid_base_stuff[] = {
	E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
	E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
	E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
	E(PROC_TGID_AUXV,      "auxv",	  S_IFREG|S_IRUSR),
	E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
	E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
	E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
	E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
	E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
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#ifdef CONFIG_NUMA
	E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
#endif
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	E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
#ifdef CONFIG_SECCOMP
	E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
#endif
	E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
	E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
	E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
	E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
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	E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
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#ifdef CONFIG_MMU
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	E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
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#endif
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#ifdef CONFIG_SECURITY
	E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
#endif
#ifdef CONFIG_KALLSYMS
	E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_SCHEDSTATS
	E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_CPUSETS
	E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
#endif
	E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
	E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
#ifdef CONFIG_AUDITSYSCALL
	E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
	{0,0,NULL,0}
};
static struct pid_entry tid_base_stuff[] = {
	E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
	E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
	E(PROC_TID_AUXV,       "auxv",	  S_IFREG|S_IRUSR),
	E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
	E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
	E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
	E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
	E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
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#ifdef CONFIG_NUMA
	E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
#endif
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	E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
#ifdef CONFIG_SECCOMP
	E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
#endif
	E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
	E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
	E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
	E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
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#ifdef CONFIG_MMU
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	E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
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#endif
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#ifdef CONFIG_SECURITY
	E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
#endif
#ifdef CONFIG_KALLSYMS
	E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_SCHEDSTATS
	E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_CPUSETS
	E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
#endif
	E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
	E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
#ifdef CONFIG_AUDITSYSCALL
	E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
	{0,0,NULL,0}
};

#ifdef CONFIG_SECURITY
static struct pid_entry tgid_attr_stuff[] = {
	E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
	E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
	E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
	E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
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	E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
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	E(PROC_TGID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
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	{0,0,NULL,0}
};
static struct pid_entry tid_attr_stuff[] = {
	E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
	E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
	E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
	E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
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	E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
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	E(PROC_TID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
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	{0,0,NULL,0}
};
#endif

#undef E

static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
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	struct task_struct *task = get_proc_task(inode);
	struct files_struct *files = NULL;
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	struct file *file;
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	int fd = proc_fd(inode);
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	if (task) {
		files = get_files_struct(task);
		put_task_struct(task);
	}
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	if (files) {
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		/*
		 * We are not taking a ref to the file structure, so we must
		 * hold ->file_lock.
		 */
		spin_lock(&files->file_lock);
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		file = fcheck_files(files, fd);
		if (file) {
			*mnt = mntget(file->f_vfsmnt);
			*dentry = dget(file->f_dentry);
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			spin_unlock(&files->file_lock);
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			put_files_struct(files);
			return 0;
		}
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		spin_unlock(&files->file_lock);
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		put_files_struct(files);
	}
	return -ENOENT;
}

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static struct fs_struct *get_fs_struct(struct task_struct *task)
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{
	struct fs_struct *fs;
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	task_lock(task);
	fs = task->fs;
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	if(fs)
		atomic_inc(&fs->count);
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	task_unlock(task);
	return fs;
}

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static int get_nr_threads(struct task_struct *tsk)
{
	/* Must be called with the rcu_read_lock held */
	unsigned long flags;
	int count = 0;

	if (lock_task_sighand(tsk, &flags)) {
		count = atomic_read(&tsk->signal->count);
		unlock_task_sighand(tsk, &flags);
	}
	return count;
}

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static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
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	struct task_struct *task = get_proc_task(inode);
	struct fs_struct *fs = NULL;
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	int result = -ENOENT;
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	if (task) {
		fs = get_fs_struct(task);
		put_task_struct(task);
	}
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	if (fs) {
		read_lock(&fs->lock);
		*mnt = mntget(fs->pwdmnt);
		*dentry = dget(fs->pwd);
		read_unlock(&fs->lock);
		result = 0;
		put_fs_struct(fs);
	}
	return result;
}

static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
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	struct task_struct *task = get_proc_task(inode);
	struct fs_struct *fs = NULL;
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	int result = -ENOENT;
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	if (task) {
		fs = get_fs_struct(task);
		put_task_struct(task);
	}
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	if (fs) {
		read_lock(&fs->lock);
		*mnt = mntget(fs->rootmnt);
		*dentry = dget(fs->root);
		read_unlock(&fs->lock);
		result = 0;
		put_fs_struct(fs);
	}
	return result;
}

#define MAY_PTRACE(task) \
	(task == current || \
	(task->parent == current && \
	(task->ptrace & PT_PTRACED) && \
	 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
	 security_ptrace(current,task) == 0))

static int proc_pid_environ(struct task_struct *task, char * buffer)
{
	int res = 0;
	struct mm_struct *mm = get_task_mm(task);
	if (mm) {
		unsigned int len = mm->env_end - mm->env_start;
		if (len > PAGE_SIZE)
			len = PAGE_SIZE;
		res = access_process_vm(task, mm->env_start, buffer, len, 0);
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		if (!ptrace_may_attach(task))
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			res = -ESRCH;
		mmput(mm);
	}
	return res;
}

static int proc_pid_cmdline(struct task_struct *task, char * buffer)
{
	int res = 0;
	unsigned int len;
	struct mm_struct *mm = get_task_mm(task);
	if (!mm)
		goto out;
	if (!mm->arg_end)
		goto out_mm;	/* Shh! No looking before we're done */

 	len = mm->arg_end - mm->arg_start;
 
	if (len > PAGE_SIZE)
		len = PAGE_SIZE;
 
	res = access_process_vm(task, mm->arg_start, buffer, len, 0);

	// If the nul at the end of args has been overwritten, then
	// assume application is using setproctitle(3).
	if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
		len = strnlen(buffer, res);
		if (len < res) {
		    res = len;
		} else {
			len = mm->env_end - mm->env_start;
			if (len > PAGE_SIZE - res)
				len = PAGE_SIZE - res;
			res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
			res = strnlen(buffer, res);
		}
	}
out_mm:
	mmput(mm);
out:
	return res;
}

static int proc_pid_auxv(struct task_struct *task, char *buffer)
{
	int res = 0;
	struct mm_struct *mm = get_task_mm(task);
	if (mm) {
		unsigned int nwords = 0;
		do
			nwords += 2;
		while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
		res = nwords * sizeof(mm->saved_auxv[0]);
		if (res > PAGE_SIZE)
			res = PAGE_SIZE;
		memcpy(buffer, mm->saved_auxv, res);
		mmput(mm);
	}
	return res;
}


#ifdef CONFIG_KALLSYMS
/*
 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 * Returns the resolved symbol.  If that fails, simply return the address.
 */
static int proc_pid_wchan(struct task_struct *task, char *buffer)
{
	char *modname;
	const char *sym_name;
	unsigned long wchan, size, offset;
	char namebuf[KSYM_NAME_LEN+1];

	wchan = get_wchan(task);

	sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
	if (sym_name)
		return sprintf(buffer, "%s", sym_name);
	return sprintf(buffer, "%lu", wchan);
}
#endif /* CONFIG_KALLSYMS */

#ifdef CONFIG_SCHEDSTATS
/*
 * Provides /proc/PID/schedstat
 */
static int proc_pid_schedstat(struct task_struct *task, char *buffer)
{
	return sprintf(buffer, "%lu %lu %lu\n",
			task->sched_info.cpu_time,
			task->sched_info.run_delay,
			task->sched_info.pcnt);
}
#endif

/* The badness from the OOM killer */
unsigned long badness(struct task_struct *p, unsigned long uptime);
static int proc_oom_score(struct task_struct *task, char *buffer)
{
	unsigned long points;
	struct timespec uptime;

	do_posix_clock_monotonic_gettime(&uptime);
	points = badness(task, uptime.tv_sec);
	return sprintf(buffer, "%lu\n", points);
}

/************************************************************************/
/*                       Here the fs part begins                        */
/************************************************************************/

/* permission checks */
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static int proc_fd_access_allowed(struct inode *inode)
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{
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	struct task_struct *task;
	int allowed = 0;
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	/* Allow access to a task's file descriptors if it is us or we
	 * may use ptrace attach to the process and find out that
	 * information.
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	 */
	task = get_proc_task(inode);
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	if (task) {
		allowed = ptrace_may_attach(task);
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		put_task_struct(task);
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	}
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	return allowed;
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}

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static int proc_setattr(struct dentry *dentry, struct iattr *attr)
{
	int error;
	struct inode *inode = dentry->d_inode;

	if (attr->ia_valid & ATTR_MODE)
		return -EPERM;

	error = inode_change_ok(inode, attr);
	if (!error) {
		error = security_inode_setattr(dentry, attr);
		if (!error)
			error = inode_setattr(inode, attr);
	}
	return error;
}

static struct inode_operations proc_def_inode_operations = {
	.setattr	= proc_setattr,
};

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extern struct seq_operations mounts_op;
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struct proc_mounts {
	struct seq_file m;
	int event;
};

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static int mounts_open(struct inode *inode, struct file *file)
{
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	struct task_struct *task = get_proc_task(inode);
	struct namespace *namespace = NULL;
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	struct proc_mounts *p;
	int ret = -EINVAL;
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	if (task) {
		task_lock(task);
		namespace = task->namespace;
		if (namespace)
			get_namespace(namespace);
		task_unlock(task);
		put_task_struct(task);
	}
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	if (namespace) {
		ret = -ENOMEM;
		p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
		if (p) {
			file->private_data = &p->m;
			ret = seq_open(file, &mounts_op);
			if (!ret) {
				p->m.private = namespace;
				p->event = namespace->event;
				return 0;
			}
			kfree(p);
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		}
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		put_namespace(namespace);
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	}
	return ret;
}

static int mounts_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = file->private_data;
	struct namespace *namespace = m->private;
	put_namespace(namespace);
	return seq_release(inode, file);
}

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static unsigned mounts_poll(struct file *file, poll_table *wait)
{
	struct proc_mounts *p = file->private_data;
	struct namespace *ns = p->m.private;
	unsigned res = 0;

	poll_wait(file, &ns->poll, wait);

	spin_lock(&vfsmount_lock);
	if (p->event != ns->event) {
		p->event = ns->event;
		res = POLLERR;
	}
	spin_unlock(&vfsmount_lock);

	return res;
}

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static struct file_operations proc_mounts_operations = {
	.open		= mounts_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
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	.poll		= mounts_poll,
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};

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extern struct seq_operations mountstats_op;
static int mountstats_open(struct inode *inode, struct file *file)
{
	int ret = seq_open(file, &mountstats_op);

	if (!ret) {
		struct seq_file *m = file->private_data;
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		struct namespace *namespace = NULL;
		struct task_struct *task = get_proc_task(inode);

		if (task) {
			task_lock(task);
			namespace = task->namespace;
			if (namespace)
				get_namespace(namespace);
			task_unlock(task);
			put_task_struct(task);
		}
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		if (namespace)
			m->private = namespace;
		else {
			seq_release(inode, file);
			ret = -EINVAL;
		}
	}
	return ret;
}

static struct file_operations proc_mountstats_operations = {
	.open		= mountstats_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
};

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#define PROC_BLOCK_SIZE	(3*1024)		/* 4K page size but our output routines use some slack for overruns */

static ssize_t proc_info_read(struct file * file, char __user * buf,
			  size_t count, loff_t *ppos)
{
	struct inode * inode = file->f_dentry->d_inode;
	unsigned long page;
	ssize_t length;
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	struct task_struct *task = get_proc_task(inode);

	length = -ESRCH;
	if (!task)
		goto out_no_task;
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	if (count > PROC_BLOCK_SIZE)
		count = PROC_BLOCK_SIZE;
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	length = -ENOMEM;
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	if (!(page = __get_free_page(GFP_KERNEL)))
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		goto out;
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	length = PROC_I(inode)->op.proc_read(task, (char*)page);

	if (length >= 0)
		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
	free_page(page);
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out:
	put_task_struct(task);
out_no_task:
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	return length;
}

static struct file_operations proc_info_file_operations = {
	.read		= proc_info_read,
};

static int mem_open(struct inode* inode, struct file* file)
{
	file->private_data = (void*)((long)current->self_exec_id);
	return 0;
}

static ssize_t mem_read(struct file * file, char __user * buf,
			size_t count, loff_t *ppos)
{
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	struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
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	char *page;
	unsigned long src = *ppos;
	int ret = -ESRCH;
	struct mm_struct *mm;

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	if (!task)
		goto out_no_task;

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	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
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		goto out;

	ret = -ENOMEM;
	page = (char *)__get_free_page(GFP_USER);
	if (!page)
		goto out;

	ret = 0;
 
	mm = get_task_mm(task);
	if (!mm)
		goto out_free;

	ret = -EIO;
 
	if (file->private_data != (void*)((long)current->self_exec_id))
		goto out_put;

	ret = 0;
 
	while (count > 0) {
		int this_len, retval;

		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
		retval = access_process_vm(task, src, page, this_len, 0);
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		if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
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			if (!ret)
				ret = -EIO;
			break;
		}

		if (copy_to_user(buf, page, retval)) {
			ret = -EFAULT;
			break;
		}
 
		ret += retval;
		src += retval;
		buf += retval;
		count -= retval;
	}
	*ppos = src;

out_put:
	mmput(mm);
out_free:
	free_page((unsigned long) page);
out:
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	put_task_struct(task);
out_no_task:
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	return ret;
}

#define mem_write NULL

#ifndef mem_write
/* This is a security hazard */
static ssize_t mem_write(struct file * file, const char * buf,
			 size_t count, loff_t *ppos)
{
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	int copied;
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	char *page;
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	struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
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	unsigned long dst = *ppos;

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	copied = -ESRCH;
	if (!task)
		goto out_no_task;

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	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
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		goto out;
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	copied = -ENOMEM;
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	page = (char *)__get_free_page(GFP_USER);
	if (!page)
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		goto out;
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	copied = 0;
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	while (count > 0) {
		int this_len, retval;

		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
		if (copy_from_user(page, buf, this_len)) {
			copied = -EFAULT;
			break;
		}
		retval = access_process_vm(task, dst, page, this_len, 1);
		if (!retval) {
			if (!copied)
				copied = -EIO;
			break;
		}
		copied += retval;
		buf += retval;
		dst += retval;
		count -= retval;			
	}
	*ppos = dst;
	free_page((unsigned long) page);
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out:
	put_task_struct(task);
out_no_task:
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	return copied;
}
#endif

static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
{
	switch (orig) {
	case 0:
		file->f_pos = offset;
		break;
	case 1:
		file->f_pos += offset;
		break;
	default:
		return -EINVAL;
	}
	force_successful_syscall_return();
	return file->f_pos;
}

static struct file_operations proc_mem_operations = {
	.llseek		= mem_lseek,
	.read		= mem_read,
	.write		= mem_write,
	.open		= mem_open,
};

static ssize_t oom_adjust_read(struct file *file, char __user *buf,
				size_t count, loff_t *ppos)
{
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	struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
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	char buffer[PROC_NUMBUF];
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	size_t len;
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	int oom_adjust;
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	loff_t __ppos = *ppos;

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	if (!task)
		return -ESRCH;
	oom_adjust = task->oomkilladj;
	put_task_struct(task);

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	len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
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	if (__ppos >= len)
		return 0;
	if (count > len-__ppos)
		count = len-__ppos;
	if (copy_to_user(buf, buffer + __ppos, count))
		return -EFAULT;
	*ppos = __ppos + count;
	return count;
}

static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
				size_t count, loff_t *ppos)
{
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	struct task_struct *task;
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	char buffer[PROC_NUMBUF], *end;
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	int oom_adjust;

	if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;
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	memset(buffer, 0, sizeof(buffer));
	if (count > sizeof(buffer) - 1)
		count = sizeof(buffer) - 1;
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	if (copy_from_user(buffer, buf, count))
		return -EFAULT;
	oom_adjust = simple_strtol(buffer, &end, 0);
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	if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
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		return -EINVAL;
	if (*end == '\n')
		end++;
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	task = get_proc_task(file->f_dentry->d_inode);
	if (!task)
		return -ESRCH;
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	task->oomkilladj = oom_adjust;
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	put_task_struct(task);
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	if (end - buffer == 0)
		return -EIO;
	return end - buffer;
}

static struct file_operations proc_oom_adjust_operations = {
	.read		= oom_adjust_read,
	.write		= oom_adjust_write,
};

#ifdef CONFIG_AUDITSYSCALL
#define TMPBUFLEN 21
static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
				  size_t count, loff_t *ppos)
{
	struct inode * inode = file->f_dentry->d_inode;
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	struct task_struct *task = get_proc_task(inode);
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	ssize_t length;
	char tmpbuf[TMPBUFLEN];

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	if (!task)
		return -ESRCH;
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	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
				audit_get_loginuid(task->audit_context));
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	put_task_struct(task);
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	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
				   size_t count, loff_t *ppos)
{
	struct inode * inode = file->f_dentry->d_inode;
	char *page, *tmp;
	ssize_t length;
	uid_t loginuid;

	if (!capable(CAP_AUDIT_CONTROL))
		return -EPERM;

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	if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
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		return -EPERM;

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	if (count >= PAGE_SIZE)
		count = PAGE_SIZE - 1;
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	if (*ppos != 0) {
		/* No partial writes. */
		return -EINVAL;
	}
	page = (char*)__get_free_page(GFP_USER);
	if (!page)
		return -ENOMEM;
	length = -EFAULT;
	if (copy_from_user(page, buf, count))
		goto out_free_page;

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	page[count] = '\0';
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	loginuid = simple_strtoul(page, &tmp, 10);
	if (tmp == page) {
		length = -EINVAL;
		goto out_free_page;

	}
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	length = audit_set_loginuid(current, loginuid);
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	if (likely(length == 0))
		length = count;

out_free_page:
	free_page((unsigned long) page);
	return length;
}

static struct file_operations proc_loginuid_operations = {
	.read		= proc_loginuid_read,
	.write		= proc_loginuid_write,
};
#endif

#ifdef CONFIG_SECCOMP
static ssize_t seccomp_read(struct file *file, char __user *buf,
			    size_t count, loff_t *ppos)
{
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	struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
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	char __buf[20];
	loff_t __ppos = *ppos;
	size_t len;

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	if (!tsk)
		return -ESRCH;
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	/* no need to print the trailing zero, so use only len */
	len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
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	put_task_struct(tsk);
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	if (__ppos >= len)
		return 0;
	if (count > len - __ppos)
		count = len - __ppos;
	if (copy_to_user(buf, __buf + __ppos, count))
		return -EFAULT;
	*ppos = __ppos + count;
	return count;
}

static ssize_t seccomp_write(struct file *file, const char __user *buf,
			     size_t count, loff_t *ppos)
{
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	struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
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	char __buf[20], *end;
	unsigned int seccomp_mode;
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	ssize_t result;

	result = -ESRCH;
	if (!tsk)
		goto out_no_task;
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	/* can set it only once to be even more secure */
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	result = -EPERM;
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	if (unlikely(tsk->seccomp.mode))
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		goto out;
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	result = -EFAULT;
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	memset(__buf, 0, sizeof(__buf));
	count = min(count, sizeof(__buf) - 1);
	if (copy_from_user(__buf, buf, count))
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		goto out;

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	seccomp_mode = simple_strtoul(__buf, &end, 0);
	if (*end == '\n')
		end++;
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	result = -EINVAL;
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	if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
		tsk->seccomp.mode = seccomp_mode;
		set_tsk_thread_flag(tsk, TIF_SECCOMP);
	} else
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		goto out;
	result = -EIO;
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	if (unlikely(!(end - __buf)))
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		goto out;
	result = end - __buf;
out:
	put_task_struct(tsk);
out_no_task:
	return result;
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}

static struct file_operations proc_seccomp_operations = {
	.read		= seccomp_read,
	.write		= seccomp_write,
};
#endif /* CONFIG_SECCOMP */

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static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
	struct inode *inode = dentry->d_inode;
	int error = -EACCES;

	/* We don't need a base pointer in the /proc filesystem */
	path_release(nd);

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	/* Are we allowed to snoop on the tasks file descriptors? */
	if (!proc_fd_access_allowed(inode))
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		goto out;

	error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
	nd->last_type = LAST_BIND;
out:
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	return ERR_PTR(error);
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}

static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
			    char __user *buffer, int buflen)
{
	struct inode * inode;
	char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
	int len;

	if (!tmp)
		return -ENOMEM;
		
	inode = dentry->d_inode;
	path = d_path(dentry, mnt, tmp, PAGE_SIZE);
	len = PTR_ERR(path);
	if (IS_ERR(path))
		goto out;
	len = tmp + PAGE_SIZE - 1 - path;

	if (len > buflen)
		len = buflen;
	if (copy_to_user(buffer, path, len))
		len = -EFAULT;
 out:
	free_page((unsigned long)tmp);
	return len;
}

static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
{
	int error = -EACCES;
	struct inode *inode = dentry->d_inode;
	struct dentry *de;
	struct vfsmount *mnt = NULL;

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	/* Are we allowed to snoop on the tasks file descriptors? */
	if (!proc_fd_access_allowed(inode))
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		goto out;

	error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
	if (error)
		goto out;

	error = do_proc_readlink(de, mnt, buffer, buflen);
	dput(de);
	mntput(mnt);
out:
	return error;
}

static struct inode_operations proc_pid_link_inode_operations = {
	.readlink	= proc_pid_readlink,
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	.follow_link	= proc_pid_follow_link,
	.setattr	= proc_setattr,
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};

static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
{
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	struct dentry *dentry = filp->f_dentry;
	struct inode *inode = dentry->d_inode;
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	struct task_struct *p = get_proc_task(inode);
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	unsigned int fd, tid, ino;
	int retval;
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	char buf[PROC_NUMBUF];
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	struct files_struct * files;
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	struct fdtable *fdt;
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	retval = -ENOENT;
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	if (!p)
		goto out_no_task;
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	retval = 0;
	tid = p->pid;

	fd = filp->f_pos;
	switch (fd) {
		case 0:
			if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
				goto out;
			filp->f_pos++;
		case 1:
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			ino = parent_ino(dentry);
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			if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
				goto out;
			filp->f_pos++;
		default:
			files = get_files_struct(p);
			if (!files)
				goto out;
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			rcu_read_lock();
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			fdt = files_fdtable(files);
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			for (fd = filp->f_pos-2;
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			     fd < fdt->max_fds;
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			     fd++, filp->f_pos++) {
				unsigned int i,j;

				if (!fcheck_files(files, fd))
					continue;
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				rcu_read_unlock();
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				j = PROC_NUMBUF;
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				i = fd;
				do {
					j--;
					buf[j] = '0' + (i % 10);
					i /= 10;
				} while (i);

				ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
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				if (filldir(dirent, buf+j, PROC_NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
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					rcu_read_lock();
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					break;
				}
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				rcu_read_lock();
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			}
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			rcu_read_unlock();
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			put_files_struct(files);
	}
out:
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	put_task_struct(p);
out_no_task:
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	return retval;
}

static int proc_pident_readdir(struct file *filp,
		void *dirent, filldir_t filldir,
		struct pid_entry *ents, unsigned int nents)
{
	int i;
	int pid;
	struct dentry *dentry = filp->f_dentry;
	struct inode *inode = dentry->d_inode;
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	struct task_struct *task = get_proc_task(inode);
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	struct pid_entry *p;
	ino_t ino;
	int ret;

	ret = -ENOENT;
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	if (!task)
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		goto out;

	ret = 0;
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	pid = task->pid;
	put_task_struct(task);
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	i = filp->f_pos;
	switch (i) {
	case 0:
		ino = inode->i_ino;
		if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
			goto out;
		i++;
		filp->f_pos++;
		/* fall through */
	case 1:
		ino = parent_ino(dentry);
		if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
			goto out;
		i++;
		filp->f_pos++;
		/* fall through */
	default:
		i -= 2;
		if (i >= nents) {
			ret = 1;
			goto out;
		}
		p = ents + i;
		while (p->name) {
			if (filldir(dirent, p->name, p->len, filp->f_pos,
				    fake_ino(pid, p->type), p->mode >> 12) < 0)
				goto out;
			filp->f_pos++;
			p++;
		}
	}

	ret = 1;
out:
	return ret;
}

static int proc_tgid_base_readdir(struct file * filp,
			     void * dirent, filldir_t filldir)
{
	return proc_pident_readdir(filp,dirent,filldir,
				   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
}

static int proc_tid_base_readdir(struct file * filp,
			     void * dirent, filldir_t filldir)
{
	return proc_pident_readdir(filp,dirent,filldir,
				   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
}

/* building an inode */

static int task_dumpable(struct task_struct *task)
{
	int dumpable = 0;
	struct mm_struct *mm;

	task_lock(task);
	mm = task->mm;
	if (mm)
		dumpable = mm->dumpable;
	task_unlock(task);
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	if(dumpable == 1)
		return 1;
	return 0;
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}


static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
{
	struct inode * inode;
	struct proc_inode *ei;

	/* We need a new inode */
	
	inode = new_inode(sb);
	if (!inode)
		goto out;

	/* Common stuff */
	ei = PROC_I(inode);
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	inode->i_ino = fake_ino(task->pid, ino);
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	inode->i_op = &proc_def_inode_operations;
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	/*
	 * grab the reference to task.
	 */
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	ei->pid = get_pid(task->pids[PIDTYPE_PID].pid);
	if (!ei->pid)
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		goto out_unlock;

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	inode->i_uid = 0;
	inode->i_gid = 0;
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	if (task_dumpable(task)) {
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		inode->i_uid = task->euid;
		inode->i_gid = task->egid;
	}
	security_task_to_inode(task, inode);

out:
	return inode;

out_unlock:
	iput(inode);
	return NULL;
}

/* dentry stuff */

/*
 *	Exceptional case: normally we are not allowed to unhash a busy
 * directory. In this case, however, we can do it - no aliasing problems
 * due to the way we treat inodes.
 *
 * Rewrite the inode's ownerships here because the owning task may have
 * performed a setuid(), etc.
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 *
 * Before the /proc/pid/status file was created the only way to read
 * the effective uid of a /process was to stat /proc/pid.  Reading
 * /proc/pid/status is slow enough that procps and other packages
 * kept stating /proc/pid.  To keep the rules in /proc simple I have
 * made this apply to all per process world readable and executable
 * directories.
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 */
static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	struct inode *inode = dentry->d_inode;
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	struct task_struct *task = get_proc_task(inode);
	if (task) {
		if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
		    task_dumpable(task)) {
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			inode->i_uid = task->euid;
			inode->i_gid = task->egid;
		} else {
			inode->i_uid = 0;
			inode->i_gid = 0;
		}
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		inode->i_mode &= ~(S_ISUID | S_ISGID);
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		security_task_to_inode(task, inode);
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		put_task_struct(task);
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		return 1;
	}
	d_drop(dentry);
	return 0;
}

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static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
	struct inode *inode = dentry->d_inode;
	struct task_struct *task;
	generic_fillattr(inode, stat);

	rcu_read_lock();
	stat->uid = 0;
	stat->gid = 0;
	task = pid_task(proc_pid(inode), PIDTYPE_PID);
	if (task) {
		if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
		    task_dumpable(task)) {
			stat->uid = task->euid;
			stat->gid = task->egid;
		}
	}
	rcu_read_unlock();
	return 0;
}

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static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	struct inode *inode = dentry->d_inode;
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	struct task_struct *task = get_proc_task(inode);
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	int fd = proc_fd(inode);
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	struct files_struct *files;

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	if (task) {
		files = get_files_struct(task);
		if (files) {
			rcu_read_lock();
			if (fcheck_files(files, fd)) {
				rcu_read_unlock();
				put_files_struct(files);
				if (task_dumpable(task)) {
					inode->i_uid = task->euid;
					inode->i_gid = task->egid;
				} else {
					inode->i_uid = 0;
					inode->i_gid = 0;
				}
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				inode->i_mode &= ~(S_ISUID | S_ISGID);
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				security_task_to_inode(task, inode);
				put_task_struct(task);
				return 1;
			}
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			rcu_read_unlock();
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			put_files_struct(files);
		}
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		put_task_struct(task);
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	}
	d_drop(dentry);
	return 0;
}

static int pid_delete_dentry(struct dentry * dentry)
{
	/* Is the task we represent dead?
	 * If so, then don't put the dentry on the lru list,
	 * kill it immediately.
	 */
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	return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
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}

static struct dentry_operations tid_fd_dentry_operations =
{
	.d_revalidate	= tid_fd_revalidate,
	.d_delete	= pid_delete_dentry,
};

static struct dentry_operations pid_dentry_operations =
{
	.d_revalidate	= pid_revalidate,
	.d_delete	= pid_delete_dentry,
};

/* Lookups */

static unsigned name_to_int(struct dentry *dentry)
{
	const char *name = dentry->d_name.name;
	int len = dentry->d_name.len;
	unsigned n = 0;

	if (len > 1 && *name == '0')
		goto out;
	while (len-- > 0) {
		unsigned c = *name++ - '0';
		if (c > 9)
			goto out;
		if (n >= (~0U-9)/10)
			goto out;
		n *= 10;
		n += c;
	}
	return n;
out:
	return ~0U;
}

/* SMP-safe */
static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
{
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	struct task_struct *task = get_proc_task(dir);
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	unsigned fd = name_to_int(dentry);
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	struct dentry *result = ERR_PTR(-ENOENT);
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	struct file * file;
	struct files_struct * files;
	struct inode *inode;
	struct proc_inode *ei;

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	if (!task)
		goto out_no_task;
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	if (fd == ~0U)
		goto out;

	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
	if (!inode)
		goto out;
	ei = PROC_I(inode);
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	ei->fd = fd;
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	files = get_files_struct(task);
	if (!files)
		goto out_unlock;
	inode->i_mode = S_IFLNK;
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	/*
	 * We are not taking a ref to the file structure, so we must
	 * hold ->file_lock.
	 */
	spin_lock(&files->file_lock);
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	file = fcheck_files(files, fd);
	if (!file)
		goto out_unlock2;
	if (file->f_mode & 1)
		inode->i_mode |= S_IRUSR | S_IXUSR;
	if (file->f_mode & 2)
		inode->i_mode |= S_IWUSR | S_IXUSR;
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	spin_unlock(&files->file_lock);
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	put_files_struct(files);
	inode->i_op = &proc_pid_link_inode_operations;
	inode->i_size = 64;
	ei->op.proc_get_link = proc_fd_link;
	dentry->d_op = &tid_fd_dentry_operations;
	d_add(dentry, inode);
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	/* Close the race of the process dying before we return the dentry */
	if (tid_fd_revalidate(dentry, NULL))
		result = NULL;
out:
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	put_task_struct(task);
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	return result;
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out_unlock2:
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	spin_unlock(&files->file_lock);
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	put_files_struct(files);
out_unlock:
	iput(inode);
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	goto out;
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}

static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
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static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
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static struct file_operations proc_fd_operations = {
	.read		= generic_read_dir,
	.readdir	= proc_readfd,
};

static struct file_operations proc_task_operations = {
	.read		= generic_read_dir,
	.readdir	= proc_task_readdir,
};

/*
 * proc directories can do almost nothing..
 */
static struct inode_operations proc_fd_inode_operations = {
	.lookup		= proc_lookupfd,
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	.setattr	= proc_setattr,
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};

static struct inode_operations proc_task_inode_operations = {
	.lookup		= proc_task_lookup,
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	.getattr	= proc_task_getattr,
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	.setattr	= proc_setattr,
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};

#ifdef CONFIG_SECURITY
static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
				  size_t count, loff_t *ppos)
{
	struct inode * inode = file->f_dentry->d_inode;
	unsigned long page;
	ssize_t length;
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	struct task_struct *task = get_proc_task(inode);

	length = -ESRCH;
	if (!task)
		goto out_no_task;
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	if (count > PAGE_SIZE)
		count = PAGE_SIZE;
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	length = -ENOMEM;
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	if (!(page = __get_free_page(GFP_KERNEL)))
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		goto out;
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	length = security_getprocattr(task, 
				      (char*)file->f_dentry->d_name.name, 
				      (void*)page, count);
	if (length >= 0)
		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
	free_page(page);
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out:
	put_task_struct(task);
out_no_task:
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	return length;
}

static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
				   size_t count, loff_t *ppos)
{ 
	struct inode * inode = file->f_dentry->d_inode;
	char *page; 
	ssize_t length; 
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	struct task_struct *task = get_proc_task(inode);
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	length = -ESRCH;
	if (!task)
		goto out_no_task;
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	if (count > PAGE_SIZE) 
		count = PAGE_SIZE; 
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	/* No partial writes. */
	length = -EINVAL;
	if (*ppos != 0)
		goto out;

	length = -ENOMEM;
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	page = (char*)__get_free_page(GFP_USER); 
	if (!page) 
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		goto out;

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	length = -EFAULT; 
	if (copy_from_user(page, buf, count)) 
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		goto out_free;
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	length = security_setprocattr(task, 
				      (char*)file->f_dentry->d_name.name, 
				      (void*)page, count);