| /* |
| * fs/sysfs/dir.c - sysfs core and dir operation implementation |
| * |
| * Copyright (c) 2001-3 Patrick Mochel |
| * Copyright (c) 2007 SUSE Linux Products GmbH |
| * Copyright (c) 2007 Tejun Heo <teheo@suse.de> |
| * |
| * This file is released under the GPLv2. |
| * |
| * Please see Documentation/filesystems/sysfs.txt for more information. |
| */ |
| |
| #undef DEBUG |
| |
| #include <linux/fs.h> |
| #include <linux/mount.h> |
| #include <linux/module.h> |
| #include <linux/kobject.h> |
| #include <linux/namei.h> |
| #include <linux/idr.h> |
| #include <linux/completion.h> |
| #include <linux/mutex.h> |
| #include <linux/slab.h> |
| #include <linux/security.h> |
| #include <linux/hash.h> |
| #include "sysfs.h" |
| |
| DEFINE_MUTEX(sysfs_mutex); |
| DEFINE_SPINLOCK(sysfs_assoc_lock); |
| |
| #define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb) |
| |
| static DEFINE_SPINLOCK(sysfs_ino_lock); |
| static DEFINE_IDA(sysfs_ino_ida); |
| |
| /** |
| * sysfs_name_hash |
| * @name: Null terminated string to hash |
| * @ns: Namespace tag to hash |
| * |
| * Returns 31 bit hash of ns + name (so it fits in an off_t ) |
| */ |
| static unsigned int sysfs_name_hash(const char *name, const void *ns) |
| { |
| unsigned long hash = init_name_hash(); |
| unsigned int len = strlen(name); |
| while (len--) |
| hash = partial_name_hash(*name++, hash); |
| hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); |
| hash &= 0x7fffffffU; |
| /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ |
| if (hash < 1) |
| hash += 2; |
| if (hash >= INT_MAX) |
| hash = INT_MAX - 1; |
| return hash; |
| } |
| |
| static int sysfs_name_compare(unsigned int hash, const char *name, |
| const void *ns, const struct sysfs_dirent *sd) |
| { |
| if (hash != sd->s_hash) |
| return hash - sd->s_hash; |
| if (ns != sd->s_ns) |
| return ns - sd->s_ns; |
| return strcmp(name, sd->s_name); |
| } |
| |
| static int sysfs_sd_compare(const struct sysfs_dirent *left, |
| const struct sysfs_dirent *right) |
| { |
| return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns, |
| right); |
| } |
| |
| /** |
| * sysfs_link_sibling - link sysfs_dirent into sibling rbtree |
| * @sd: sysfs_dirent of interest |
| * |
| * Link @sd into its sibling rbtree which starts from |
| * sd->s_parent->s_dir.children. |
| * |
| * Locking: |
| * mutex_lock(sysfs_mutex) |
| * |
| * RETURNS: |
| * 0 on susccess -EEXIST on failure. |
| */ |
| static int sysfs_link_sibling(struct sysfs_dirent *sd) |
| { |
| struct rb_node **node = &sd->s_parent->s_dir.children.rb_node; |
| struct rb_node *parent = NULL; |
| |
| if (sysfs_type(sd) == SYSFS_DIR) |
| sd->s_parent->s_dir.subdirs++; |
| |
| while (*node) { |
| struct sysfs_dirent *pos; |
| int result; |
| |
| pos = to_sysfs_dirent(*node); |
| parent = *node; |
| result = sysfs_sd_compare(sd, pos); |
| if (result < 0) |
| node = &pos->s_rb.rb_left; |
| else if (result > 0) |
| node = &pos->s_rb.rb_right; |
| else |
| return -EEXIST; |
| } |
| /* add new node and rebalance the tree */ |
| rb_link_node(&sd->s_rb, parent, node); |
| rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children); |
| |
| /* if @sd has ns tag, mark the parent to enable ns filtering */ |
| if (sd->s_ns) |
| sd->s_parent->s_flags |= SYSFS_FLAG_HAS_NS; |
| |
| return 0; |
| } |
| |
| /** |
| * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree |
| * @sd: sysfs_dirent of interest |
| * |
| * Unlink @sd from its sibling rbtree which starts from |
| * sd->s_parent->s_dir.children. |
| * |
| * Locking: |
| * mutex_lock(sysfs_mutex) |
| */ |
| static void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
| { |
| if (sysfs_type(sd) == SYSFS_DIR) |
| sd->s_parent->s_dir.subdirs--; |
| |
| rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children); |
| |
| /* |
| * Either all or none of the children have tags. Clearing HAS_NS |
| * when there's no child left is enough to keep the flag synced. |
| */ |
| if (RB_EMPTY_ROOT(&sd->s_parent->s_dir.children)) |
| sd->s_parent->s_flags &= ~SYSFS_FLAG_HAS_NS; |
| } |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| |
| /* Test for attributes that want to ignore lockdep for read-locking */ |
| static bool ignore_lockdep(struct sysfs_dirent *sd) |
| { |
| return sysfs_type(sd) == SYSFS_KOBJ_ATTR && |
| sd->s_attr.attr->ignore_lockdep; |
| } |
| |
| #else |
| |
| static inline bool ignore_lockdep(struct sysfs_dirent *sd) |
| { |
| return true; |
| } |
| |
| #endif |
| |
| /** |
| * sysfs_get_active - get an active reference to sysfs_dirent |
| * @sd: sysfs_dirent to get an active reference to |
| * |
| * Get an active reference of @sd. This function is noop if @sd |
| * is NULL. |
| * |
| * RETURNS: |
| * Pointer to @sd on success, NULL on failure. |
| */ |
| struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) |
| { |
| if (unlikely(!sd)) |
| return NULL; |
| |
| if (!atomic_inc_unless_negative(&sd->s_active)) |
| return NULL; |
| |
| if (likely(!ignore_lockdep(sd))) |
| rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); |
| return sd; |
| } |
| |
| /** |
| * sysfs_put_active - put an active reference to sysfs_dirent |
| * @sd: sysfs_dirent to put an active reference to |
| * |
| * Put an active reference to @sd. This function is noop if @sd |
| * is NULL. |
| */ |
| void sysfs_put_active(struct sysfs_dirent *sd) |
| { |
| int v; |
| |
| if (unlikely(!sd)) |
| return; |
| |
| if (likely(!ignore_lockdep(sd))) |
| rwsem_release(&sd->dep_map, 1, _RET_IP_); |
| v = atomic_dec_return(&sd->s_active); |
| if (likely(v != SD_DEACTIVATED_BIAS)) |
| return; |
| |
| /* atomic_dec_return() is a mb(), we'll always see the updated |
| * sd->u.completion. |
| */ |
| complete(sd->u.completion); |
| } |
| |
| /** |
| * sysfs_deactivate - deactivate sysfs_dirent |
| * @sd: sysfs_dirent to deactivate |
| * |
| * Deny new active references and drain existing ones. |
| */ |
| static void sysfs_deactivate(struct sysfs_dirent *sd) |
| { |
| DECLARE_COMPLETION_ONSTACK(wait); |
| int v; |
| |
| BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED)); |
| |
| if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) |
| return; |
| |
| sd->u.completion = (void *)&wait; |
| |
| rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); |
| /* atomic_add_return() is a mb(), put_active() will always see |
| * the updated sd->u.completion. |
| */ |
| v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
| |
| if (v != SD_DEACTIVATED_BIAS) { |
| lock_contended(&sd->dep_map, _RET_IP_); |
| wait_for_completion(&wait); |
| } |
| |
| lock_acquired(&sd->dep_map, _RET_IP_); |
| rwsem_release(&sd->dep_map, 1, _RET_IP_); |
| } |
| |
| static int sysfs_alloc_ino(unsigned int *pino) |
| { |
| int ino, rc; |
| |
| retry: |
| spin_lock(&sysfs_ino_lock); |
| rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); |
| spin_unlock(&sysfs_ino_lock); |
| |
| if (rc == -EAGAIN) { |
| if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) |
| goto retry; |
| rc = -ENOMEM; |
| } |
| |
| *pino = ino; |
| return rc; |
| } |
| |
| static void sysfs_free_ino(unsigned int ino) |
| { |
| spin_lock(&sysfs_ino_lock); |
| ida_remove(&sysfs_ino_ida, ino); |
| spin_unlock(&sysfs_ino_lock); |
| } |
| |
| void release_sysfs_dirent(struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent *parent_sd; |
| |
| repeat: |
| /* Moving/renaming is always done while holding reference. |
| * sd->s_parent won't change beneath us. |
| */ |
| parent_sd = sd->s_parent; |
| |
| WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED), |
| "sysfs: free using entry: %s/%s\n", |
| parent_sd ? parent_sd->s_name : "", sd->s_name); |
| |
| if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
| sysfs_put(sd->s_symlink.target_sd); |
| if (sysfs_type(sd) & SYSFS_COPY_NAME) |
| kfree(sd->s_name); |
| if (sd->s_iattr && sd->s_iattr->ia_secdata) |
| security_release_secctx(sd->s_iattr->ia_secdata, |
| sd->s_iattr->ia_secdata_len); |
| kfree(sd->s_iattr); |
| sysfs_free_ino(sd->s_ino); |
| kmem_cache_free(sysfs_dir_cachep, sd); |
| |
| sd = parent_sd; |
| if (sd && atomic_dec_and_test(&sd->s_count)) |
| goto repeat; |
| } |
| |
| static int sysfs_dentry_delete(const struct dentry *dentry) |
| { |
| struct sysfs_dirent *sd = dentry->d_fsdata; |
| return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
| } |
| |
| static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
| { |
| struct sysfs_dirent *sd; |
| |
| if (flags & LOOKUP_RCU) |
| return -ECHILD; |
| |
| sd = dentry->d_fsdata; |
| mutex_lock(&sysfs_mutex); |
| |
| /* The sysfs dirent has been deleted */ |
| if (sd->s_flags & SYSFS_FLAG_REMOVED) |
| goto out_bad; |
| |
| /* The sysfs dirent has been moved? */ |
| if (dentry->d_parent->d_fsdata != sd->s_parent) |
| goto out_bad; |
| |
| /* The sysfs dirent has been renamed */ |
| if (strcmp(dentry->d_name.name, sd->s_name) != 0) |
| goto out_bad; |
| |
| /* The sysfs dirent has been moved to a different namespace */ |
| if (sd->s_ns && sd->s_ns != sysfs_info(dentry->d_sb)->ns) |
| goto out_bad; |
| |
| mutex_unlock(&sysfs_mutex); |
| out_valid: |
| return 1; |
| out_bad: |
| /* Remove the dentry from the dcache hashes. |
| * If this is a deleted dentry we use d_drop instead of d_delete |
| * so sysfs doesn't need to cope with negative dentries. |
| * |
| * If this is a dentry that has simply been renamed we |
| * use d_drop to remove it from the dcache lookup on its |
| * old parent. If this dentry persists later when a lookup |
| * is performed at its new name the dentry will be readded |
| * to the dcache hashes. |
| */ |
| mutex_unlock(&sysfs_mutex); |
| |
| /* If we have submounts we must allow the vfs caches |
| * to lie about the state of the filesystem to prevent |
| * leaks and other nasty things. |
| */ |
| if (check_submounts_and_drop(dentry) != 0) |
| goto out_valid; |
| |
| return 0; |
| } |
| |
| static void sysfs_dentry_release(struct dentry *dentry) |
| { |
| sysfs_put(dentry->d_fsdata); |
| } |
| |
| const struct dentry_operations sysfs_dentry_ops = { |
| .d_revalidate = sysfs_dentry_revalidate, |
| .d_delete = sysfs_dentry_delete, |
| .d_release = sysfs_dentry_release, |
| }; |
| |
| struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
| { |
| char *dup_name = NULL; |
| struct sysfs_dirent *sd; |
| |
| if (type & SYSFS_COPY_NAME) { |
| name = dup_name = kstrdup(name, GFP_KERNEL); |
| if (!name) |
| return NULL; |
| } |
| |
| sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
| if (!sd) |
| goto err_out1; |
| |
| if (sysfs_alloc_ino(&sd->s_ino)) |
| goto err_out2; |
| |
| atomic_set(&sd->s_count, 1); |
| atomic_set(&sd->s_active, 0); |
| |
| sd->s_name = name; |
| sd->s_mode = mode; |
| sd->s_flags = type | SYSFS_FLAG_REMOVED; |
| |
| return sd; |
| |
| err_out2: |
| kmem_cache_free(sysfs_dir_cachep, sd); |
| err_out1: |
| kfree(dup_name); |
| return NULL; |
| } |
| |
| /** |
| * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
| * @acxt: pointer to sysfs_addrm_cxt to be used |
| * |
| * This function is called when the caller is about to add or remove |
| * sysfs_dirent. This function acquires sysfs_mutex. @acxt is used |
| * to keep and pass context to other addrm functions. |
| * |
| * LOCKING: |
| * Kernel thread context (may sleep). sysfs_mutex is locked on |
| * return. |
| */ |
| void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt) |
| __acquires(sysfs_mutex) |
| { |
| memset(acxt, 0, sizeof(*acxt)); |
| |
| mutex_lock(&sysfs_mutex); |
| } |
| |
| /** |
| * __sysfs_add_one - add sysfs_dirent to parent without warning |
| * @acxt: addrm context to use |
| * @sd: sysfs_dirent to be added |
| * @parent_sd: the parent sysfs_dirent to add @sd to |
| * |
| * Get @parent_sd and set @sd->s_parent to it and increment nlink of |
| * the 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, |
| struct sysfs_dirent *parent_sd) |
| { |
| struct sysfs_inode_attrs *ps_iattr; |
| int ret; |
| |
| sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); |
| sd->s_parent = sysfs_get(parent_sd); |
| |
| ret = sysfs_link_sibling(sd); |
| if (ret) |
| return ret; |
| |
| /* Update timestamps on the parent */ |
| ps_iattr = 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; |
| } |
| |
| /* Mark the entry added into directory tree */ |
| sd->s_flags &= ~SYSFS_FLAG_REMOVED; |
| |
| return 0; |
| } |
| |
| /** |
| * sysfs_pathname - return full path to sysfs dirent |
| * @sd: sysfs_dirent whose path we want |
| * @path: caller allocated buffer of size PATH_MAX |
| * |
| * Gives the name "/" to the sysfs_root entry; any path returned |
| * is relative to wherever sysfs is mounted. |
| */ |
| static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) |
| { |
| if (sd->s_parent) { |
| sysfs_pathname(sd->s_parent, path); |
| strlcat(path, "/", PATH_MAX); |
| } |
| strlcat(path, sd->s_name, PATH_MAX); |
| return path; |
| } |
| |
| /** |
| * sysfs_add_one - add sysfs_dirent to parent |
| * @acxt: addrm context to use |
| * @sd: sysfs_dirent to be added |
| * @parent_sd: the parent sysfs_dirent to add @sd to |
| * |
| * Get @parent_sd and set @sd->s_parent to it and increment nlink of |
| * the 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, |
| struct sysfs_dirent *parent_sd) |
| { |
| int ret; |
| |
| ret = __sysfs_add_one(acxt, sd, parent_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(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(). |
| */ |
| static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, |
| struct sysfs_dirent *sd) |
| { |
| struct sysfs_inode_attrs *ps_iattr; |
| |
| /* |
| * Removal can be called multiple times on the same node. Only the |
| * first invocation is effective and puts the base ref. |
| */ |
| if (sd->s_flags & SYSFS_FLAG_REMOVED) |
| return; |
| |
| sysfs_unlink_sibling(sd); |
| |
| /* Update timestamps on the parent */ |
| ps_iattr = sd->s_parent->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) |
| __releases(sysfs_mutex) |
| { |
| /* 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 |
| * @ns: the namespace tag to use |
| * |
| * 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 unsigned char *name, |
| const void *ns) |
| { |
| struct rb_node *node = parent_sd->s_dir.children.rb_node; |
| unsigned int hash; |
| |
| hash = sysfs_name_hash(name, ns); |
| while (node) { |
| struct sysfs_dirent *sd; |
| int result; |
| |
| sd = to_sysfs_dirent(node); |
| result = sysfs_name_compare(hash, name, ns, sd); |
| if (result < 0) |
| node = node->rb_left; |
| else if (result > 0) |
| node = node->rb_right; |
| else |
| return sd; |
| } |
| return NULL; |
| } |
| |
| /** |
| * sysfs_get_dirent_ns - find and get sysfs_dirent with the given name |
| * @parent_sd: sysfs_dirent to search under |
| * @name: name to look for |
| * @ns: the namespace tag to use |
| * |
| * 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_ns(struct sysfs_dirent *parent_sd, |
| const unsigned char *name, |
| const void *ns) |
| { |
| struct sysfs_dirent *sd; |
| |
| mutex_lock(&sysfs_mutex); |
| sd = sysfs_find_dirent(parent_sd, name, ns); |
| sysfs_get(sd); |
| mutex_unlock(&sysfs_mutex); |
| |
| return sd; |
| } |
| EXPORT_SYMBOL_GPL(sysfs_get_dirent_ns); |
| |
| static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
| const char *name, const void *ns, |
| 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_ns = ns; |
| sd->s_dir.kobj = kobj; |
| |
| /* link in */ |
| sysfs_addrm_start(&acxt); |
| rc = sysfs_add_one(&acxt, sd, parent_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, name, NULL, p_sd); |
| } |
| |
| /** |
| * sysfs_create_dir_ns - create a directory for an object with a namespace tag |
| * @kobj: object we're creating directory for |
| * @ns: the namespace tag to use |
| */ |
| int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) |
| { |
| struct sysfs_dirent *parent_sd, *sd; |
| int error = 0; |
| |
| BUG_ON(!kobj); |
| |
| if (kobj->parent) |
| parent_sd = kobj->parent->sd; |
| else |
| parent_sd = &sysfs_root; |
| |
| if (!parent_sd) |
| return -ENOENT; |
| |
| error = create_dir(kobj, parent_sd, kobject_name(kobj), ns, &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; |
| const void *ns = NULL; |
| |
| mutex_lock(&sysfs_mutex); |
| |
| if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS) |
| ns = sysfs_info(dir->i_sb)->ns; |
| |
| sd = sysfs_find_dirent(parent_sd, dentry->d_name.name, ns); |
| |
| /* 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 struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos) |
| { |
| struct sysfs_dirent *last; |
| |
| while (true) { |
| struct rb_node *rbn; |
| |
| last = pos; |
| |
| if (sysfs_type(pos) != SYSFS_DIR) |
| break; |
| |
| rbn = rb_first(&pos->s_dir.children); |
| if (!rbn) |
| break; |
| |
| pos = to_sysfs_dirent(rbn); |
| } |
| |
| return last; |
| } |
| |
| /** |
| * sysfs_next_descendant_post - find the next descendant for post-order walk |
| * @pos: the current position (%NULL to initiate traversal) |
| * @root: sysfs_dirent whose descendants to walk |
| * |
| * Find the next descendant to visit for post-order traversal of @root's |
| * descendants. @root is included in the iteration and the last node to be |
| * visited. |
| */ |
| static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos, |
| struct sysfs_dirent *root) |
| { |
| struct rb_node *rbn; |
| |
| lockdep_assert_held(&sysfs_mutex); |
| |
| /* if first iteration, visit leftmost descendant which may be root */ |
| if (!pos) |
| return sysfs_leftmost_descendant(root); |
| |
| /* if we visited @root, we're done */ |
| if (pos == root) |
| return NULL; |
| |
| /* if there's an unvisited sibling, visit its leftmost descendant */ |
| rbn = rb_next(&pos->s_rb); |
| if (rbn) |
| return sysfs_leftmost_descendant(to_sysfs_dirent(rbn)); |
| |
| /* no sibling left, visit parent */ |
| return pos->s_parent; |
| } |
| |
| void __sysfs_remove(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent *pos, *next; |
| |
| if (!sd) |
| return; |
| |
| pr_debug("sysfs %s: removing\n", sd->s_name); |
| |
| next = NULL; |
| do { |
| pos = next; |
| next = sysfs_next_descendant_post(pos, sd); |
| if (pos) |
| sysfs_remove_one(acxt, pos); |
| } while (next); |
| } |
| |
| /** |
| * sysfs_remove - remove a sysfs_dirent recursively |
| * @sd: the sysfs_dirent to remove |
| * |
| * Remove @sd along with all its subdirectories and files. |
| */ |
| void sysfs_remove(struct sysfs_dirent *sd) |
| { |
| struct sysfs_addrm_cxt acxt; |
| |
| sysfs_addrm_start(&acxt); |
| __sysfs_remove(&acxt, sd); |
| sysfs_addrm_finish(&acxt); |
| } |
| |
| /** |
| * 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); |
| |
| if (sd) { |
| WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR); |
| sysfs_remove(sd); |
| } |
| } |
| |
| int sysfs_rename(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd, |
| const char *new_name, const void *new_ns) |
| { |
| 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_name, new_ns)) |
| 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_name, sd->s_ns); |
| sd->s_parent = new_parent_sd; |
| sysfs_link_sibling(sd); |
| |
| error = 0; |
| out: |
| mutex_unlock(&sysfs_mutex); |
| return error; |
| } |
| |
| int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name, |
| const void *new_ns) |
| { |
| struct sysfs_dirent *parent_sd = kobj->sd->s_parent; |
| |
| return sysfs_rename(kobj->sd, parent_sd, new_name, new_ns); |
| } |
| |
| int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, |
| const void *new_ns) |
| { |
| struct sysfs_dirent *sd = kobj->sd; |
| struct sysfs_dirent *new_parent_sd; |
| |
| BUG_ON(!sd->s_parent); |
| new_parent_sd = new_parent_kobj && new_parent_kobj->sd ? |
| new_parent_kobj->sd : &sysfs_root; |
| |
| return sysfs_rename(sd, new_parent_sd, sd->s_name, new_ns); |
| } |
| |
| /* 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 *file, struct dir_context *ctx) |
| { |
| struct dentry *dentry = file->f_path.dentry; |
| struct sysfs_dirent *parent_sd = dentry->d_fsdata; |
| struct sysfs_dirent *pos = file->private_data; |
| const void *ns = NULL; |
| |
| if (!dir_emit_dots(file, ctx)) |
| return 0; |
| mutex_lock(&sysfs_mutex); |
| |
| if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS) |
| ns = sysfs_info(dentry->d_sb)->ns; |
| |
| for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos); |
| pos; |
| pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) { |
| const char *name = pos->s_name; |
| unsigned int type = dt_type(pos); |
| int len = strlen(name); |
| ino_t ino = pos->s_ino; |
| ctx->pos = pos->s_hash; |
| file->private_data = sysfs_get(pos); |
| |
| mutex_unlock(&sysfs_mutex); |
| if (!dir_emit(ctx, name, len, ino, type)) |
| return 0; |
| mutex_lock(&sysfs_mutex); |
| } |
| mutex_unlock(&sysfs_mutex); |
| file->private_data = NULL; |
| ctx->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, |
| .iterate = sysfs_readdir, |
| .release = sysfs_dir_release, |
| .llseek = sysfs_dir_llseek, |
| }; |