mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-09 11:56:40 +07:00
bb2b0051d7
It might be a kernel disaster if one sysfs entry is freed but still referenced by sysfs tree. Recently Dave and Sasha reported one use-after-free problem on sysfs entry, and the problem has been troubleshooted with help of debug message added in this patch. Given sysfs_get_dirent/sysfs_put are exported APIs, even inside sysfs they are called in many contexts(kobject/attribe add/delete, inode init/drop, dentry lookup/release, readdir, ...), it is healthful to check the removed flag before freeing one entry and dump message if it is freeing without being removed first. Cc: Dave Jones <davej@redhat.com> Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1084 lines
25 KiB
C
1084 lines
25 KiB
C
/*
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* fs/sysfs/dir.c - sysfs core and dir operation implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#undef DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include <linux/completion.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/hash.h>
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#include "sysfs.h"
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DEFINE_MUTEX(sysfs_mutex);
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DEFINE_SPINLOCK(sysfs_assoc_lock);
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#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb);
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static DEFINE_SPINLOCK(sysfs_ino_lock);
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static DEFINE_IDA(sysfs_ino_ida);
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/**
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* sysfs_name_hash
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* @ns: Namespace tag to hash
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* @name: Null terminated string to hash
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*
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* Returns 31 bit hash of ns + name (so it fits in an off_t )
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*/
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static unsigned int sysfs_name_hash(const void *ns, const char *name)
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{
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unsigned long hash = init_name_hash();
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unsigned int len = strlen(name);
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while (len--)
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hash = partial_name_hash(*name++, hash);
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hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) );
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hash &= 0x7fffffffU;
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/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
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if (hash < 1)
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hash += 2;
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if (hash >= INT_MAX)
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hash = INT_MAX - 1;
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return hash;
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}
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static int sysfs_name_compare(unsigned int hash, const void *ns,
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const char *name, const struct sysfs_dirent *sd)
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{
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if (hash != sd->s_hash)
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return hash - sd->s_hash;
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if (ns != sd->s_ns)
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return ns - sd->s_ns;
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return strcmp(name, sd->s_name);
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}
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static int sysfs_sd_compare(const struct sysfs_dirent *left,
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const struct sysfs_dirent *right)
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{
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return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name,
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right);
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}
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/**
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* sysfs_link_subling - link sysfs_dirent into sibling rbtree
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* @sd: sysfs_dirent of interest
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*
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* Link @sd into its sibling rbtree which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*
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* RETURNS:
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* 0 on susccess -EEXIST on failure.
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*/
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static int sysfs_link_sibling(struct sysfs_dirent *sd)
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{
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struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
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struct rb_node *parent = NULL;
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if (sysfs_type(sd) == SYSFS_DIR)
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sd->s_parent->s_dir.subdirs++;
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while (*node) {
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struct sysfs_dirent *pos;
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int result;
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pos = to_sysfs_dirent(*node);
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parent = *node;
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result = sysfs_sd_compare(sd, pos);
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if (result < 0)
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node = &pos->s_rb.rb_left;
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else if (result > 0)
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node = &pos->s_rb.rb_right;
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else
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return -EEXIST;
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}
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/* add new node and rebalance the tree */
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rb_link_node(&sd->s_rb, parent, node);
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rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
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return 0;
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}
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/**
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* sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
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* @sd: sysfs_dirent of interest
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*
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* Unlink @sd from its sibling rbtree which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*/
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static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
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{
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if (sysfs_type(sd) == SYSFS_DIR)
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sd->s_parent->s_dir.subdirs--;
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rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
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}
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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/* Test for attributes that want to ignore lockdep for read-locking */
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static bool ignore_lockdep(struct sysfs_dirent *sd)
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{
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return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
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sd->s_attr.attr->ignore_lockdep;
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}
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#else
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static inline bool ignore_lockdep(struct sysfs_dirent *sd)
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{
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return true;
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}
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#endif
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/**
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* sysfs_get_active - get an active reference to sysfs_dirent
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* @sd: sysfs_dirent to get an active reference to
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*
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* Get an active reference of @sd. This function is noop if @sd
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* is NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
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{
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if (unlikely(!sd))
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return NULL;
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if (!atomic_inc_unless_negative(&sd->s_active))
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return NULL;
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if (likely(!ignore_lockdep(sd)))
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rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
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return sd;
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}
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/**
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* sysfs_put_active - put an active reference to sysfs_dirent
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* @sd: sysfs_dirent to put an active reference to
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*
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* Put an active reference to @sd. This function is noop if @sd
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* is NULL.
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*/
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void sysfs_put_active(struct sysfs_dirent *sd)
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{
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int v;
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if (unlikely(!sd))
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return;
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if (likely(!ignore_lockdep(sd)))
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rwsem_release(&sd->dep_map, 1, _RET_IP_);
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v = atomic_dec_return(&sd->s_active);
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if (likely(v != SD_DEACTIVATED_BIAS))
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return;
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/* atomic_dec_return() is a mb(), we'll always see the updated
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* sd->u.completion.
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*/
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complete(sd->u.completion);
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}
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/**
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* sysfs_deactivate - deactivate sysfs_dirent
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* @sd: sysfs_dirent to deactivate
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*
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* Deny new active references and drain existing ones.
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*/
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static void sysfs_deactivate(struct sysfs_dirent *sd)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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int v;
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BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
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if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
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return;
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sd->u.completion = (void *)&wait;
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rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated sd->u.completion.
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*/
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v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
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if (v != SD_DEACTIVATED_BIAS) {
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lock_contended(&sd->dep_map, _RET_IP_);
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wait_for_completion(&wait);
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}
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lock_acquired(&sd->dep_map, _RET_IP_);
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rwsem_release(&sd->dep_map, 1, _RET_IP_);
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}
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static int sysfs_alloc_ino(unsigned int *pino)
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{
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int ino, rc;
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retry:
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spin_lock(&sysfs_ino_lock);
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rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
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spin_unlock(&sysfs_ino_lock);
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if (rc == -EAGAIN) {
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if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
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goto retry;
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rc = -ENOMEM;
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}
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*pino = ino;
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return rc;
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}
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static void sysfs_free_ino(unsigned int ino)
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{
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spin_lock(&sysfs_ino_lock);
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ida_remove(&sysfs_ino_ida, ino);
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spin_unlock(&sysfs_ino_lock);
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}
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void release_sysfs_dirent(struct sysfs_dirent * sd)
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{
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struct sysfs_dirent *parent_sd;
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repeat:
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/* Moving/renaming is always done while holding reference.
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* sd->s_parent won't change beneath us.
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*/
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parent_sd = sd->s_parent;
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WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
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"sysfs: free using entry: %s/%s\n",
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parent_sd ? parent_sd->s_name : "", sd->s_name);
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if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
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sysfs_put(sd->s_symlink.target_sd);
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if (sysfs_type(sd) & SYSFS_COPY_NAME)
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kfree(sd->s_name);
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if (sd->s_iattr && sd->s_iattr->ia_secdata)
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security_release_secctx(sd->s_iattr->ia_secdata,
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sd->s_iattr->ia_secdata_len);
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kfree(sd->s_iattr);
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sysfs_free_ino(sd->s_ino);
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kmem_cache_free(sysfs_dir_cachep, sd);
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sd = parent_sd;
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if (sd && atomic_dec_and_test(&sd->s_count))
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goto repeat;
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}
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static int sysfs_dentry_delete(const struct dentry *dentry)
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{
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struct sysfs_dirent *sd = dentry->d_fsdata;
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return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
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}
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static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct sysfs_dirent *sd;
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int is_dir;
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int type;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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sd = dentry->d_fsdata;
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mutex_lock(&sysfs_mutex);
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/* The sysfs dirent has been deleted */
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if (sd->s_flags & SYSFS_FLAG_REMOVED)
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goto out_bad;
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/* The sysfs dirent has been moved? */
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if (dentry->d_parent->d_fsdata != sd->s_parent)
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goto out_bad;
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/* The sysfs dirent has been renamed */
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if (strcmp(dentry->d_name.name, sd->s_name) != 0)
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goto out_bad;
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/* The sysfs dirent has been moved to a different namespace */
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type = KOBJ_NS_TYPE_NONE;
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if (sd->s_parent) {
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type = sysfs_ns_type(sd->s_parent);
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if (type != KOBJ_NS_TYPE_NONE &&
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sysfs_info(dentry->d_sb)->ns[type] != sd->s_ns)
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goto out_bad;
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}
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mutex_unlock(&sysfs_mutex);
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out_valid:
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return 1;
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out_bad:
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/* Remove the dentry from the dcache hashes.
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* If this is a deleted dentry we use d_drop instead of d_delete
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* so sysfs doesn't need to cope with negative dentries.
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*
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* If this is a dentry that has simply been renamed we
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* use d_drop to remove it from the dcache lookup on its
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* old parent. If this dentry persists later when a lookup
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* is performed at its new name the dentry will be readded
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* to the dcache hashes.
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*/
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is_dir = (sysfs_type(sd) == SYSFS_DIR);
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mutex_unlock(&sysfs_mutex);
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if (is_dir) {
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/* If we have submounts we must allow the vfs caches
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* to lie about the state of the filesystem to prevent
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* leaks and other nasty things.
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*/
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if (have_submounts(dentry))
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goto out_valid;
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shrink_dcache_parent(dentry);
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}
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d_drop(dentry);
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return 0;
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}
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static void sysfs_dentry_release(struct dentry *dentry)
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{
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sysfs_put(dentry->d_fsdata);
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}
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const struct dentry_operations sysfs_dentry_ops = {
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.d_revalidate = sysfs_dentry_revalidate,
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.d_delete = sysfs_dentry_delete,
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.d_release = sysfs_dentry_release,
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};
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struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
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{
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char *dup_name = NULL;
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struct sysfs_dirent *sd;
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if (type & SYSFS_COPY_NAME) {
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name = dup_name = kstrdup(name, GFP_KERNEL);
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if (!name)
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return NULL;
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}
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sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
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if (!sd)
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goto err_out1;
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if (sysfs_alloc_ino(&sd->s_ino))
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goto err_out2;
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atomic_set(&sd->s_count, 1);
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atomic_set(&sd->s_active, 0);
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sd->s_name = name;
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sd->s_mode = mode;
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sd->s_flags = type | SYSFS_FLAG_REMOVED;
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return sd;
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err_out2:
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kmem_cache_free(sysfs_dir_cachep, sd);
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err_out1:
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kfree(dup_name);
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return NULL;
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}
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/**
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* sysfs_addrm_start - prepare for sysfs_dirent add/remove
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* @acxt: pointer to sysfs_addrm_cxt to be used
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* @parent_sd: parent sysfs_dirent
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*
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* This function is called when the caller is about to add or
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* remove sysfs_dirent under @parent_sd. This function acquires
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* sysfs_mutex. @acxt is used to keep and pass context to
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* other addrm functions.
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*
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* LOCKING:
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* Kernel thread context (may sleep). sysfs_mutex is locked on
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* return.
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*/
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void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
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struct sysfs_dirent *parent_sd)
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{
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memset(acxt, 0, sizeof(*acxt));
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acxt->parent_sd = parent_sd;
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mutex_lock(&sysfs_mutex);
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}
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/**
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* __sysfs_add_one - add sysfs_dirent to parent without warning
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* @acxt: addrm context to use
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* @sd: sysfs_dirent to be added
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*
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* Get @acxt->parent_sd and set sd->s_parent to it and increment
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* nlink of parent inode if @sd is a directory and link into the
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* children list of the parent.
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*
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* This function should be called between calls to
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* sysfs_addrm_start() and sysfs_addrm_finish() and should be
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* passed the same @acxt as passed to sysfs_addrm_start().
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*
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* LOCKING:
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* Determined by sysfs_addrm_start().
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*
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* RETURNS:
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* 0 on success, -EEXIST if entry with the given name already
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* exists.
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*/
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int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
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{
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struct sysfs_inode_attrs *ps_iattr;
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int ret;
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|
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if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
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WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
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sysfs_ns_type(acxt->parent_sd)? "required": "invalid",
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acxt->parent_sd->s_name, sd->s_name);
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return -EINVAL;
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}
|
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|
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sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
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sd->s_parent = sysfs_get(acxt->parent_sd);
|
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|
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ret = sysfs_link_sibling(sd);
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if (ret)
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return ret;
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = acxt->parent_sd->s_iattr;
|
|
if (ps_iattr) {
|
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struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
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ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
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}
|
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|
|
/* Mark the entry added into directory tree */
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sd->s_flags &= ~SYSFS_FLAG_REMOVED;
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|
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return 0;
|
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}
|
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|
|
/**
|
|
* sysfs_pathname - return full path to sysfs dirent
|
|
* @sd: sysfs_dirent whose path we want
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|
* @path: caller allocated buffer of size PATH_MAX
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*
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* Gives the name "/" to the sysfs_root entry; any path returned
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* is relative to wherever sysfs is mounted.
|
|
*/
|
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static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
|
|
{
|
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if (sd->s_parent) {
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sysfs_pathname(sd->s_parent, path);
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strlcat(path, "/", PATH_MAX);
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}
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strlcat(path, sd->s_name, PATH_MAX);
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return path;
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}
|
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|
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/**
|
|
* sysfs_add_one - add sysfs_dirent to parent
|
|
* @acxt: addrm context to use
|
|
* @sd: sysfs_dirent to be added
|
|
*
|
|
* Get @acxt->parent_sd and set sd->s_parent to it and increment
|
|
* nlink of parent inode if @sd is a directory and link into the
|
|
* children list of the parent.
|
|
*
|
|
* This function should be called between calls to
|
|
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
|
|
* passed the same @acxt as passed to sysfs_addrm_start().
|
|
*
|
|
* LOCKING:
|
|
* Determined by sysfs_addrm_start().
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -EEXIST if entry with the given name already
|
|
* exists.
|
|
*/
|
|
int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
|
|
{
|
|
int ret;
|
|
|
|
ret = __sysfs_add_one(acxt, sd);
|
|
if (ret == -EEXIST) {
|
|
char *path = kzalloc(PATH_MAX, GFP_KERNEL);
|
|
WARN(1, KERN_WARNING
|
|
"sysfs: cannot create duplicate filename '%s'\n",
|
|
(path == NULL) ? sd->s_name
|
|
: (sysfs_pathname(acxt->parent_sd, path),
|
|
strlcat(path, "/", PATH_MAX),
|
|
strlcat(path, sd->s_name, PATH_MAX),
|
|
path));
|
|
kfree(path);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_one - remove sysfs_dirent from parent
|
|
* @acxt: addrm context to use
|
|
* @sd: sysfs_dirent to be removed
|
|
*
|
|
* Mark @sd removed and drop nlink of parent inode if @sd is a
|
|
* directory. @sd is unlinked from the children list.
|
|
*
|
|
* This function should be called between calls to
|
|
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
|
|
* passed the same @acxt as passed to sysfs_addrm_start().
|
|
*
|
|
* LOCKING:
|
|
* Determined by sysfs_addrm_start().
|
|
*/
|
|
void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_inode_attrs *ps_iattr;
|
|
|
|
BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
|
|
|
|
sysfs_unlink_sibling(sd);
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = acxt->parent_sd->s_iattr;
|
|
if (ps_iattr) {
|
|
struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
|
|
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
|
|
}
|
|
|
|
sd->s_flags |= SYSFS_FLAG_REMOVED;
|
|
sd->u.removed_list = acxt->removed;
|
|
acxt->removed = sd;
|
|
}
|
|
|
|
/**
|
|
* sysfs_addrm_finish - finish up sysfs_dirent add/remove
|
|
* @acxt: addrm context to finish up
|
|
*
|
|
* Finish up sysfs_dirent add/remove. Resources acquired by
|
|
* sysfs_addrm_start() are released and removed sysfs_dirents are
|
|
* cleaned up.
|
|
*
|
|
* LOCKING:
|
|
* sysfs_mutex is released.
|
|
*/
|
|
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
|
|
{
|
|
/* release resources acquired by sysfs_addrm_start() */
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
/* kill removed sysfs_dirents */
|
|
while (acxt->removed) {
|
|
struct sysfs_dirent *sd = acxt->removed;
|
|
|
|
acxt->removed = sd->u.removed_list;
|
|
|
|
sysfs_deactivate(sd);
|
|
unmap_bin_file(sd);
|
|
sysfs_put(sd);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* sysfs_find_dirent - find sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd.
|
|
*
|
|
* LOCKING:
|
|
* mutex_lock(sysfs_mutex)
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
|
|
const void *ns,
|
|
const unsigned char *name)
|
|
{
|
|
struct rb_node *node = parent_sd->s_dir.children.rb_node;
|
|
unsigned int hash;
|
|
|
|
if (!!sysfs_ns_type(parent_sd) != !!ns) {
|
|
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
|
|
sysfs_ns_type(parent_sd)? "required": "invalid",
|
|
parent_sd->s_name, name);
|
|
return NULL;
|
|
}
|
|
|
|
hash = sysfs_name_hash(ns, name);
|
|
while (node) {
|
|
struct sysfs_dirent *sd;
|
|
int result;
|
|
|
|
sd = to_sysfs_dirent(node);
|
|
result = sysfs_name_compare(hash, ns, name, sd);
|
|
if (result < 0)
|
|
node = node->rb_left;
|
|
else if (result > 0)
|
|
node = node->rb_right;
|
|
else
|
|
return sd;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_dirent - find and get sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd and get
|
|
* it if found.
|
|
*
|
|
* LOCKING:
|
|
* Kernel thread context (may sleep). Grabs sysfs_mutex.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
|
|
const void *ns,
|
|
const unsigned char *name)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sd = sysfs_find_dirent(parent_sd, ns, name);
|
|
sysfs_get(sd);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
return sd;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_get_dirent);
|
|
|
|
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
|
|
enum kobj_ns_type type, const void *ns, const char *name,
|
|
struct sysfs_dirent **p_sd)
|
|
{
|
|
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
int rc;
|
|
|
|
/* allocate */
|
|
sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
|
|
if (!sd)
|
|
return -ENOMEM;
|
|
|
|
sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
|
|
sd->s_ns = ns;
|
|
sd->s_dir.kobj = kobj;
|
|
|
|
/* link in */
|
|
sysfs_addrm_start(&acxt, parent_sd);
|
|
rc = sysfs_add_one(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (rc == 0)
|
|
*p_sd = sd;
|
|
else
|
|
sysfs_put(sd);
|
|
|
|
return rc;
|
|
}
|
|
|
|
int sysfs_create_subdir(struct kobject *kobj, const char *name,
|
|
struct sysfs_dirent **p_sd)
|
|
{
|
|
return create_dir(kobj, kobj->sd,
|
|
KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
|
|
}
|
|
|
|
/**
|
|
* sysfs_read_ns_type: return associated ns_type
|
|
* @kobj: the kobject being queried
|
|
*
|
|
* Each kobject can be tagged with exactly one namespace type
|
|
* (i.e. network or user). Return the ns_type associated with
|
|
* this object if any
|
|
*/
|
|
static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
|
|
{
|
|
const struct kobj_ns_type_operations *ops;
|
|
enum kobj_ns_type type;
|
|
|
|
ops = kobj_child_ns_ops(kobj);
|
|
if (!ops)
|
|
return KOBJ_NS_TYPE_NONE;
|
|
|
|
type = ops->type;
|
|
BUG_ON(type <= KOBJ_NS_TYPE_NONE);
|
|
BUG_ON(type >= KOBJ_NS_TYPES);
|
|
BUG_ON(!kobj_ns_type_registered(type));
|
|
|
|
return type;
|
|
}
|
|
|
|
/**
|
|
* sysfs_create_dir - create a directory for an object.
|
|
* @kobj: object we're creating directory for.
|
|
*/
|
|
int sysfs_create_dir(struct kobject * kobj)
|
|
{
|
|
enum kobj_ns_type type;
|
|
struct sysfs_dirent *parent_sd, *sd;
|
|
const void *ns = NULL;
|
|
int error = 0;
|
|
|
|
BUG_ON(!kobj);
|
|
|
|
if (kobj->parent)
|
|
parent_sd = kobj->parent->sd;
|
|
else
|
|
parent_sd = &sysfs_root;
|
|
|
|
if (!parent_sd)
|
|
return -ENOENT;
|
|
|
|
if (sysfs_ns_type(parent_sd))
|
|
ns = kobj->ktype->namespace(kobj);
|
|
type = sysfs_read_ns_type(kobj);
|
|
|
|
error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
|
|
if (!error)
|
|
kobj->sd = sd;
|
|
return error;
|
|
}
|
|
|
|
static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct dentry *ret = NULL;
|
|
struct dentry *parent = dentry->d_parent;
|
|
struct sysfs_dirent *parent_sd = parent->d_fsdata;
|
|
struct sysfs_dirent *sd;
|
|
struct inode *inode;
|
|
enum kobj_ns_type type;
|
|
const void *ns;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
type = sysfs_ns_type(parent_sd);
|
|
ns = sysfs_info(dir->i_sb)->ns[type];
|
|
|
|
sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
|
|
|
|
/* no such entry */
|
|
if (!sd) {
|
|
ret = ERR_PTR(-ENOENT);
|
|
goto out_unlock;
|
|
}
|
|
dentry->d_fsdata = sysfs_get(sd);
|
|
|
|
/* attach dentry and inode */
|
|
inode = sysfs_get_inode(dir->i_sb, sd);
|
|
if (!inode) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* instantiate and hash dentry */
|
|
ret = d_materialise_unique(dentry, inode);
|
|
out_unlock:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return ret;
|
|
}
|
|
|
|
const struct inode_operations sysfs_dir_inode_operations = {
|
|
.lookup = sysfs_lookup,
|
|
.permission = sysfs_permission,
|
|
.setattr = sysfs_setattr,
|
|
.getattr = sysfs_getattr,
|
|
.setxattr = sysfs_setxattr,
|
|
};
|
|
|
|
static void remove_dir(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
|
|
sysfs_addrm_start(&acxt, sd->s_parent);
|
|
sysfs_remove_one(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
}
|
|
|
|
void sysfs_remove_subdir(struct sysfs_dirent *sd)
|
|
{
|
|
remove_dir(sd);
|
|
}
|
|
|
|
|
|
static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct rb_node *pos;
|
|
|
|
if (!dir_sd)
|
|
return;
|
|
|
|
pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
|
|
sysfs_addrm_start(&acxt, dir_sd);
|
|
pos = rb_first(&dir_sd->s_dir.children);
|
|
while (pos) {
|
|
struct sysfs_dirent *sd = to_sysfs_dirent(pos);
|
|
pos = rb_next(pos);
|
|
if (sysfs_type(sd) != SYSFS_DIR)
|
|
sysfs_remove_one(&acxt, sd);
|
|
}
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
remove_dir(dir_sd);
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_dir - remove an object's directory.
|
|
* @kobj: object.
|
|
*
|
|
* The only thing special about this is that we remove any files in
|
|
* the directory before we remove the directory, and we've inlined
|
|
* what used to be sysfs_rmdir() below, instead of calling separately.
|
|
*/
|
|
|
|
void sysfs_remove_dir(struct kobject * kobj)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
|
|
spin_lock(&sysfs_assoc_lock);
|
|
kobj->sd = NULL;
|
|
spin_unlock(&sysfs_assoc_lock);
|
|
|
|
__sysfs_remove_dir(sd);
|
|
}
|
|
|
|
int sysfs_rename(struct sysfs_dirent *sd,
|
|
struct sysfs_dirent *new_parent_sd, const void *new_ns,
|
|
const char *new_name)
|
|
{
|
|
int error;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
error = 0;
|
|
if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
|
|
(strcmp(sd->s_name, new_name) == 0))
|
|
goto out; /* nothing to rename */
|
|
|
|
error = -EEXIST;
|
|
if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
|
|
goto out;
|
|
|
|
/* rename sysfs_dirent */
|
|
if (strcmp(sd->s_name, new_name) != 0) {
|
|
error = -ENOMEM;
|
|
new_name = kstrdup(new_name, GFP_KERNEL);
|
|
if (!new_name)
|
|
goto out;
|
|
|
|
kfree(sd->s_name);
|
|
sd->s_name = new_name;
|
|
}
|
|
|
|
/* Move to the appropriate place in the appropriate directories rbtree. */
|
|
sysfs_unlink_sibling(sd);
|
|
sysfs_get(new_parent_sd);
|
|
sysfs_put(sd->s_parent);
|
|
sd->s_ns = new_ns;
|
|
sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
|
|
sd->s_parent = new_parent_sd;
|
|
sysfs_link_sibling(sd);
|
|
|
|
error = 0;
|
|
out:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return error;
|
|
}
|
|
|
|
int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
|
|
{
|
|
struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
|
|
const void *new_ns = NULL;
|
|
|
|
if (sysfs_ns_type(parent_sd))
|
|
new_ns = kobj->ktype->namespace(kobj);
|
|
|
|
return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
|
|
}
|
|
|
|
int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
struct sysfs_dirent *new_parent_sd;
|
|
const void *new_ns = NULL;
|
|
|
|
BUG_ON(!sd->s_parent);
|
|
if (sysfs_ns_type(sd->s_parent))
|
|
new_ns = kobj->ktype->namespace(kobj);
|
|
new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
|
|
new_parent_kobj->sd : &sysfs_root;
|
|
|
|
return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
|
|
}
|
|
|
|
/* Relationship between s_mode and the DT_xxx types */
|
|
static inline unsigned char dt_type(struct sysfs_dirent *sd)
|
|
{
|
|
return (sd->s_mode >> 12) & 15;
|
|
}
|
|
|
|
static int sysfs_dir_release(struct inode *inode, struct file *filp)
|
|
{
|
|
sysfs_put(filp->private_data);
|
|
return 0;
|
|
}
|
|
|
|
static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
|
|
struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
|
|
{
|
|
if (pos) {
|
|
int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
|
|
pos->s_parent == parent_sd &&
|
|
hash == pos->s_hash;
|
|
sysfs_put(pos);
|
|
if (!valid)
|
|
pos = NULL;
|
|
}
|
|
if (!pos && (hash > 1) && (hash < INT_MAX)) {
|
|
struct rb_node *node = parent_sd->s_dir.children.rb_node;
|
|
while (node) {
|
|
pos = to_sysfs_dirent(node);
|
|
|
|
if (hash < pos->s_hash)
|
|
node = node->rb_left;
|
|
else if (hash > pos->s_hash)
|
|
node = node->rb_right;
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
/* Skip over entries in the wrong namespace */
|
|
while (pos && pos->s_ns != ns) {
|
|
struct rb_node *node = rb_next(&pos->s_rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = to_sysfs_dirent(node);
|
|
}
|
|
return pos;
|
|
}
|
|
|
|
static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
|
|
struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
|
|
{
|
|
pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
|
|
if (pos) do {
|
|
struct rb_node *node = rb_next(&pos->s_rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = to_sysfs_dirent(node);
|
|
} while (pos && pos->s_ns != ns);
|
|
return pos;
|
|
}
|
|
|
|
static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
|
|
{
|
|
struct dentry *dentry = filp->f_path.dentry;
|
|
struct sysfs_dirent * parent_sd = dentry->d_fsdata;
|
|
struct sysfs_dirent *pos = filp->private_data;
|
|
enum kobj_ns_type type;
|
|
const void *ns;
|
|
ino_t ino;
|
|
loff_t off;
|
|
|
|
type = sysfs_ns_type(parent_sd);
|
|
ns = sysfs_info(dentry->d_sb)->ns[type];
|
|
|
|
if (filp->f_pos == 0) {
|
|
ino = parent_sd->s_ino;
|
|
if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
|
|
filp->f_pos++;
|
|
else
|
|
return 0;
|
|
}
|
|
if (filp->f_pos == 1) {
|
|
if (parent_sd->s_parent)
|
|
ino = parent_sd->s_parent->s_ino;
|
|
else
|
|
ino = parent_sd->s_ino;
|
|
if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
|
|
filp->f_pos++;
|
|
else
|
|
return 0;
|
|
}
|
|
mutex_lock(&sysfs_mutex);
|
|
off = filp->f_pos;
|
|
for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
|
|
pos;
|
|
pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
|
|
const char * name;
|
|
unsigned int type;
|
|
int len, ret;
|
|
|
|
name = pos->s_name;
|
|
len = strlen(name);
|
|
ino = pos->s_ino;
|
|
type = dt_type(pos);
|
|
off = filp->f_pos = pos->s_hash;
|
|
filp->private_data = sysfs_get(pos);
|
|
|
|
mutex_unlock(&sysfs_mutex);
|
|
ret = filldir(dirent, name, len, off, ino, type);
|
|
mutex_lock(&sysfs_mutex);
|
|
if (ret < 0)
|
|
break;
|
|
}
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
/* don't reference last entry if its refcount is dropped */
|
|
if (!pos) {
|
|
filp->private_data = NULL;
|
|
|
|
/* EOF and not changed as 0 or 1 in read/write path */
|
|
if (off == filp->f_pos && off > 1)
|
|
filp->f_pos = INT_MAX;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
loff_t ret;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
ret = generic_file_llseek(file, offset, whence);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct file_operations sysfs_dir_operations = {
|
|
.read = generic_read_dir,
|
|
.readdir = sysfs_readdir,
|
|
.release = sysfs_dir_release,
|
|
.llseek = sysfs_dir_llseek,
|
|
};
|