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linux-next/fs/autofs4/autofs_i.h
Sukadev Bhattiprolu 6eaba35b43 autofs4: allow autofs to work outside the initial PID namespace 
Enable autofs4 to work in a "container".  oz_pgrp is converted from
pid_t to struct pid and this is stored at mount time based on the
"pgrp=" option or if the option is missing then the current pgrp.

The "pgrp=" option is interpreted in the PID namespace of the current
process.  This option is flawed in that it doesn't carry the namespace
information, so it should be deprecated.  AFAICS the autofs daemon
always sends the current pgrp, which is the default anyway.

The oz_pgrp is also set from the AUTOFS_DEV_IOCTL_SETPIPEFD_CMD ioctl.
This ioctl sets oz_pgrp to the current pgrp.  It is not allowed to
change the pid namespace.

oz_pgrp is used mainly to determine whether the process traversing the
autofs mount tree is the autofs daemon itself or not.  This function now
compares the pid pointers instead of the pid_t values.

One other use of oz_pgrp is in autofs4_show_options.  There is shows the
virtual pid number (i.e.  the one that is valid inside the PID namespace
of the calling process)

For debugging printk convert oz_pgrp to the value in the initial pid
namespace.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:58 -08:00

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/* -*- c -*- ------------------------------------------------------------- *
*
* linux/fs/autofs/autofs_i.h
*
* Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
* Copyright 2005-2006 Ian Kent <raven@themaw.net>
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/* Internal header file for autofs */
#include <linux/auto_fs4.h>
#include <linux/auto_dev-ioctl.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/list.h>
/* This is the range of ioctl() numbers we claim as ours */
#define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
#define AUTOFS_IOC_COUNT 32
#define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
#define AUTOFS_DEV_IOCTL_IOC_COUNT (AUTOFS_IOC_COUNT - 11)
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/string.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <asm/current.h>
#include <asm/uaccess.h>
/* #define DEBUG */
#define DPRINTK(fmt, ...) \
pr_debug("pid %d: %s: " fmt "\n", \
current->pid, __func__, ##__VA_ARGS__)
#define AUTOFS_WARN(fmt, ...) \
printk(KERN_WARNING "pid %d: %s: " fmt "\n", \
current->pid, __func__, ##__VA_ARGS__)
#define AUTOFS_ERROR(fmt, ...) \
printk(KERN_ERR "pid %d: %s: " fmt "\n", \
current->pid, __func__, ##__VA_ARGS__)
/* Unified info structure. This is pointed to by both the dentry and
inode structures. Each file in the filesystem has an instance of this
structure. It holds a reference to the dentry, so dentries are never
flushed while the file exists. All name lookups are dealt with at the
dentry level, although the filesystem can interfere in the validation
process. Readdir is implemented by traversing the dentry lists. */
struct autofs_info {
struct dentry *dentry;
struct inode *inode;
int flags;
struct completion expire_complete;
struct list_head active;
int active_count;
struct list_head expiring;
struct autofs_sb_info *sbi;
unsigned long last_used;
atomic_t count;
kuid_t uid;
kgid_t gid;
};
#define AUTOFS_INF_EXPIRING (1<<0) /* dentry is in the process of expiring */
#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
struct autofs_wait_queue {
wait_queue_head_t queue;
struct autofs_wait_queue *next;
autofs_wqt_t wait_queue_token;
/* We use the following to see what we are waiting for */
struct qstr name;
u32 dev;
u64 ino;
kuid_t uid;
kgid_t gid;
pid_t pid;
pid_t tgid;
/* This is for status reporting upon return */
int status;
unsigned int wait_ctr;
};
#define AUTOFS_SBI_MAGIC 0x6d4a556d
struct autofs_sb_info {
u32 magic;
int pipefd;
struct file *pipe;
struct pid *oz_pgrp;
int catatonic;
int version;
int sub_version;
int min_proto;
int max_proto;
unsigned long exp_timeout;
unsigned int type;
int reghost_enabled;
int needs_reghost;
struct super_block *sb;
struct mutex wq_mutex;
struct mutex pipe_mutex;
spinlock_t fs_lock;
struct autofs_wait_queue *queues; /* Wait queue pointer */
spinlock_t lookup_lock;
struct list_head active_list;
struct list_head expiring_list;
struct rcu_head rcu;
};
static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
{
return (struct autofs_sb_info *)(sb->s_fs_info);
}
static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
{
return (struct autofs_info *)(dentry->d_fsdata);
}
/* autofs4_oz_mode(): do we see the man behind the curtain? (The
processes which do manipulations for us in user space sees the raw
filesystem without "magic".) */
static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
}
/* Does a dentry have some pending activity? */
static inline int autofs4_ispending(struct dentry *dentry)
{
struct autofs_info *inf = autofs4_dentry_ino(dentry);
if (inf->flags & AUTOFS_INF_PENDING)
return 1;
if (inf->flags & AUTOFS_INF_EXPIRING)
return 1;
return 0;
}
struct inode *autofs4_get_inode(struct super_block *, umode_t);
void autofs4_free_ino(struct autofs_info *);
/* Expiration */
int is_autofs4_dentry(struct dentry *);
int autofs4_expire_wait(struct dentry *dentry);
int autofs4_expire_run(struct super_block *, struct vfsmount *,
struct autofs_sb_info *,
struct autofs_packet_expire __user *);
int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
struct autofs_sb_info *sbi, int when);
int autofs4_expire_multi(struct super_block *, struct vfsmount *,
struct autofs_sb_info *, int __user *);
struct dentry *autofs4_expire_direct(struct super_block *sb,
struct vfsmount *mnt,
struct autofs_sb_info *sbi, int how);
struct dentry *autofs4_expire_indirect(struct super_block *sb,
struct vfsmount *mnt,
struct autofs_sb_info *sbi, int how);
/* Device node initialization */
int autofs_dev_ioctl_init(void);
void autofs_dev_ioctl_exit(void);
/* Operations structures */
extern const struct inode_operations autofs4_symlink_inode_operations;
extern const struct inode_operations autofs4_dir_inode_operations;
extern const struct file_operations autofs4_dir_operations;
extern const struct file_operations autofs4_root_operations;
extern const struct dentry_operations autofs4_dentry_operations;
/* VFS automount flags management functions */
static inline void __managed_dentry_set_automount(struct dentry *dentry)
{
dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
}
static inline void managed_dentry_set_automount(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_set_automount(dentry);
spin_unlock(&dentry->d_lock);
}
static inline void __managed_dentry_clear_automount(struct dentry *dentry)
{
dentry->d_flags &= ~DCACHE_NEED_AUTOMOUNT;
}
static inline void managed_dentry_clear_automount(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_clear_automount(dentry);
spin_unlock(&dentry->d_lock);
}
static inline void __managed_dentry_set_transit(struct dentry *dentry)
{
dentry->d_flags |= DCACHE_MANAGE_TRANSIT;
}
static inline void managed_dentry_set_transit(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_set_transit(dentry);
spin_unlock(&dentry->d_lock);
}
static inline void __managed_dentry_clear_transit(struct dentry *dentry)
{
dentry->d_flags &= ~DCACHE_MANAGE_TRANSIT;
}
static inline void managed_dentry_clear_transit(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_clear_transit(dentry);
spin_unlock(&dentry->d_lock);
}
static inline void __managed_dentry_set_managed(struct dentry *dentry)
{
dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
}
static inline void managed_dentry_set_managed(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_set_managed(dentry);
spin_unlock(&dentry->d_lock);
}
static inline void __managed_dentry_clear_managed(struct dentry *dentry)
{
dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
}
static inline void managed_dentry_clear_managed(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__managed_dentry_clear_managed(dentry);
spin_unlock(&dentry->d_lock);
}
/* Initializing function */
int autofs4_fill_super(struct super_block *, void *, int);
struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
void autofs4_clean_ino(struct autofs_info *);
static inline int autofs_prepare_pipe(struct file *pipe)
{
if (!pipe->f_op->write)
return -EINVAL;
if (!S_ISFIFO(file_inode(pipe)->i_mode))
return -EINVAL;
/* We want a packet pipe */
pipe->f_flags |= O_DIRECT;
return 0;
}
/* Queue management functions */
int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
void autofs4_catatonic_mode(struct autofs_sb_info *);
static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
{
return new_encode_dev(sbi->sb->s_dev);
}
static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
{
return sbi->sb->s_root->d_inode->i_ino;
}
static inline int simple_positive(struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
static inline void __autofs4_add_expiring(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
if (list_empty(&ino->expiring))
list_add(&ino->expiring, &sbi->expiring_list);
}
return;
}
static inline void autofs4_add_expiring(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
spin_lock(&sbi->lookup_lock);
if (list_empty(&ino->expiring))
list_add(&ino->expiring, &sbi->expiring_list);
spin_unlock(&sbi->lookup_lock);
}
return;
}
static inline void autofs4_del_expiring(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
spin_lock(&sbi->lookup_lock);
if (!list_empty(&ino->expiring))
list_del_init(&ino->expiring);
spin_unlock(&sbi->lookup_lock);
}
return;
}
extern void autofs4_kill_sb(struct super_block *);
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