diff options
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/Kconfig | 23 | ||||
| -rw-r--r-- | fs/sysfs/Makefile | 6 | ||||
| -rw-r--r-- | fs/sysfs/bin.c | 506 | ||||
| -rw-r--r-- | fs/sysfs/dir.c | 1049 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 799 | ||||
| -rw-r--r-- | fs/sysfs/group.c | 211 | ||||
| -rw-r--r-- | fs/sysfs/inode.c | 356 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 200 | ||||
| -rw-r--r-- | fs/sysfs/symlink.c | 307 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 241 |
10 files changed, 3698 insertions, 0 deletions
diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig new file mode 100644 index 00000000..8c41feac --- /dev/null +++ b/fs/sysfs/Kconfig @@ -0,0 +1,23 @@ +config SYSFS + bool "sysfs file system support" if EXPERT + default y + help + The sysfs filesystem is a virtual filesystem that the kernel uses to + export internal kernel objects, their attributes, and their + relationships to one another. + + Users can use sysfs to ascertain useful information about the running + kernel, such as the devices the kernel has discovered on each bus and + which driver each is bound to. sysfs can also be used to tune devices + and other kernel subsystems. + + Some system agents rely on the information in sysfs to operate. + /sbin/hotplug uses device and object attributes in sysfs to assist in + delegating policy decisions, like persistently naming devices. + + sysfs is currently used by the block subsystem to mount the root + partition. If sysfs is disabled you must specify the boot device on + the kernel boot command line via its major and minor numbers. For + example, "root=03:01" for /dev/hda1. + + Designers of embedded systems may wish to say N here to conserve space. diff --git a/fs/sysfs/Makefile b/fs/sysfs/Makefile new file mode 100644 index 00000000..7a1ceb94 --- /dev/null +++ b/fs/sysfs/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for the sysfs virtual filesystem +# + +obj-y := inode.o file.o dir.o symlink.o mount.o bin.o \ + group.o diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c new file mode 100644 index 00000000..a4759833 --- /dev/null +++ b/fs/sysfs/bin.c @@ -0,0 +1,506 @@ +/* + * fs/sysfs/bin.c - sysfs binary file implementation + * + * Copyright (c) 2003 Patrick Mochel + * Copyright (c) 2003 Matthew Wilcox + * Copyright (c) 2004 Silicon Graphics, Inc. + * 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/errno.h> +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/mm.h> + +#include <asm/uaccess.h> + +#include "sysfs.h" + +/* + * There's one bin_buffer for each open file. + * + * filp->private_data points to bin_buffer and + * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s + * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock + */ +static DEFINE_MUTEX(sysfs_bin_lock); + +struct bin_buffer { + struct mutex mutex; + void *buffer; + int mmapped; + const struct vm_operations_struct *vm_ops; + struct file *file; + struct hlist_node list; +}; + +static int +fill_read(struct file *file, char *buffer, loff_t off, size_t count) +{ + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + int rc; + + /* need attr_sd for attr, its parent for kobj */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + rc = -EIO; + if (attr->read) + rc = attr->read(file, kobj, attr, buffer, off, count); + + sysfs_put_active(attr_sd); + + return rc; +} + +static ssize_t +read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) +{ + struct bin_buffer *bb = file->private_data; + int size = file->f_path.dentry->d_inode->i_size; + loff_t offs = *off; + int count = min_t(size_t, bytes, PAGE_SIZE); + char *temp; + + if (!bytes) + return 0; + + if (size) { + if (offs > size) + return 0; + if (offs + count > size) + count = size - offs; + } + + temp = kmalloc(count, GFP_KERNEL); + if (!temp) + return -ENOMEM; + + mutex_lock(&bb->mutex); + + count = fill_read(file, bb->buffer, offs, count); + if (count < 0) { + mutex_unlock(&bb->mutex); + goto out_free; + } + + memcpy(temp, bb->buffer, count); + + mutex_unlock(&bb->mutex); + + if (copy_to_user(userbuf, temp, count)) { + count = -EFAULT; + goto out_free; + } + + pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count); + + *off = offs + count; + + out_free: + kfree(temp); + return count; +} + +static int +flush_write(struct file *file, char *buffer, loff_t offset, size_t count) +{ + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + int rc; + + /* need attr_sd for attr, its parent for kobj */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + rc = -EIO; + if (attr->write) + rc = attr->write(file, kobj, attr, buffer, offset, count); + + sysfs_put_active(attr_sd); + + return rc; +} + +static ssize_t write(struct file *file, const char __user *userbuf, + size_t bytes, loff_t *off) +{ + struct bin_buffer *bb = file->private_data; + int size = file->f_path.dentry->d_inode->i_size; + loff_t offs = *off; + int count = min_t(size_t, bytes, PAGE_SIZE); + char *temp; + + if (!bytes) + return 0; + + if (size) { + if (offs > size) + return 0; + if (offs + count > size) + count = size - offs; + } + + temp = memdup_user(userbuf, count); + if (IS_ERR(temp)) + return PTR_ERR(temp); + + mutex_lock(&bb->mutex); + + memcpy(bb->buffer, temp, count); + + count = flush_write(file, bb->buffer, offs, count); + mutex_unlock(&bb->mutex); + + if (count > 0) + *off = offs + count; + + kfree(temp); + return count; +} + +static void bin_vma_open(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + + if (!bb->vm_ops) + return; + + if (!sysfs_get_active(attr_sd)) + return; + + if (bb->vm_ops->open) + bb->vm_ops->open(vma); + + sysfs_put_active(attr_sd); +} + +static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return VM_FAULT_SIGBUS; + + if (!sysfs_get_active(attr_sd)) + return VM_FAULT_SIGBUS; + + ret = VM_FAULT_SIGBUS; + if (bb->vm_ops->fault) + ret = bb->vm_ops->fault(vma, vmf); + + sysfs_put_active(attr_sd); + return ret; +} + +static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return VM_FAULT_SIGBUS; + + if (!sysfs_get_active(attr_sd)) + return VM_FAULT_SIGBUS; + + ret = 0; + if (bb->vm_ops->page_mkwrite) + ret = bb->vm_ops->page_mkwrite(vma, vmf); + + sysfs_put_active(attr_sd); + return ret; +} + +static int bin_access(struct vm_area_struct *vma, unsigned long addr, + void *buf, int len, int write) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return -EINVAL; + + if (!sysfs_get_active(attr_sd)) + return -EINVAL; + + ret = -EINVAL; + if (bb->vm_ops->access) + ret = bb->vm_ops->access(vma, addr, buf, len, write); + + sysfs_put_active(attr_sd); + return ret; +} + +#ifdef CONFIG_NUMA +static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return 0; + + if (!sysfs_get_active(attr_sd)) + return -EINVAL; + + ret = 0; + if (bb->vm_ops->set_policy) + ret = bb->vm_ops->set_policy(vma, new); + + sysfs_put_active(attr_sd); + return ret; +} + +static struct mempolicy *bin_get_policy(struct vm_area_struct *vma, + unsigned long addr) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct mempolicy *pol; + + if (!bb->vm_ops) + return vma->vm_policy; + + if (!sysfs_get_active(attr_sd)) + return vma->vm_policy; + + pol = vma->vm_policy; + if (bb->vm_ops->get_policy) + pol = bb->vm_ops->get_policy(vma, addr); + + sysfs_put_active(attr_sd); + return pol; +} + +static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from, + const nodemask_t *to, unsigned long flags) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return 0; + + if (!sysfs_get_active(attr_sd)) + return 0; + + ret = 0; + if (bb->vm_ops->migrate) + ret = bb->vm_ops->migrate(vma, from, to, flags); + + sysfs_put_active(attr_sd); + return ret; +} +#endif + +static const struct vm_operations_struct bin_vm_ops = { + .open = bin_vma_open, + .fault = bin_fault, + .page_mkwrite = bin_page_mkwrite, + .access = bin_access, +#ifdef CONFIG_NUMA + .set_policy = bin_set_policy, + .get_policy = bin_get_policy, + .migrate = bin_migrate, +#endif +}; + +static int mmap(struct file *file, struct vm_area_struct *vma) +{ + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + int rc; + + mutex_lock(&bb->mutex); + + /* need attr_sd for attr, its parent for kobj */ + rc = -ENODEV; + if (!sysfs_get_active(attr_sd)) + goto out_unlock; + + rc = -EINVAL; + if (!attr->mmap) + goto out_put; + + rc = attr->mmap(file, kobj, attr, vma); + if (rc) + goto out_put; + + /* + * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() + * to satisfy versions of X which crash if the mmap fails: that + * substitutes a new vm_file, and we don't then want bin_vm_ops. + */ + if (vma->vm_file != file) + goto out_put; + + rc = -EINVAL; + if (bb->mmapped && bb->vm_ops != vma->vm_ops) + goto out_put; + + /* + * It is not possible to successfully wrap close. + * So error if someone is trying to use close. + */ + rc = -EINVAL; + if (vma->vm_ops && vma->vm_ops->close) + goto out_put; + + rc = 0; + bb->mmapped = 1; + bb->vm_ops = vma->vm_ops; + vma->vm_ops = &bin_vm_ops; +out_put: + sysfs_put_active(attr_sd); +out_unlock: + mutex_unlock(&bb->mutex); + + return rc; +} + +static int open(struct inode * inode, struct file * file) +{ + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr; + struct bin_buffer *bb = NULL; + int error; + + /* binary file operations requires both @sd and its parent */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + error = -EACCES; + if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap)) + goto err_out; + if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap)) + goto err_out; + + error = -ENOMEM; + bb = kzalloc(sizeof(*bb), GFP_KERNEL); + if (!bb) + goto err_out; + + bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!bb->buffer) + goto err_out; + + mutex_init(&bb->mutex); + bb->file = file; + file->private_data = bb; + + mutex_lock(&sysfs_bin_lock); + hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers); + mutex_unlock(&sysfs_bin_lock); + + /* open succeeded, put active references */ + sysfs_put_active(attr_sd); + return 0; + + err_out: + sysfs_put_active(attr_sd); + kfree(bb); + return error; +} + +static int release(struct inode * inode, struct file * file) +{ + struct bin_buffer *bb = file->private_data; + + mutex_lock(&sysfs_bin_lock); + hlist_del(&bb->list); + mutex_unlock(&sysfs_bin_lock); + + kfree(bb->buffer); + kfree(bb); + return 0; +} + +const struct file_operations bin_fops = { + .read = read, + .write = write, + .mmap = mmap, + .llseek = generic_file_llseek, + .open = open, + .release = release, +}; + + +void unmap_bin_file(struct sysfs_dirent *attr_sd) +{ + struct bin_buffer *bb; + struct hlist_node *tmp; + + if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR) + return; + + mutex_lock(&sysfs_bin_lock); + + hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) { + struct inode *inode = bb->file->f_path.dentry->d_inode; + + unmap_mapping_range(inode->i_mapping, 0, 0, 1); + } + + mutex_unlock(&sysfs_bin_lock); +} + +/** + * sysfs_create_bin_file - create binary file for object. + * @kobj: object. + * @attr: attribute descriptor. + */ + +int sysfs_create_bin_file(struct kobject *kobj, + const struct bin_attribute *attr) +{ + BUG_ON(!kobj || !kobj->sd || !attr); + + return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); +} + + +/** + * sysfs_remove_bin_file - remove binary file for object. + * @kobj: object. + * @attr: attribute descriptor. + */ + +void sysfs_remove_bin_file(struct kobject *kobj, + const struct bin_attribute *attr) +{ + sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name); +} + +EXPORT_SYMBOL_GPL(sysfs_create_bin_file); +EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c new file mode 100644 index 00000000..35a36d39 --- /dev/null +++ b/fs/sysfs/dir.c @@ -0,0 +1,1049 @@ +/* + * 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 + * @ns: Namespace tag to hash + * @name: Null terminated string to hash + * + * Returns 31 bit hash of ns + name (so it fits in an off_t ) + */ +static unsigned int sysfs_name_hash(const void *ns, const char *name) +{ + 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 void *ns, + const char *name, 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_ns, left->s_name, + right); +} + +/** + * sysfs_link_subling - 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); + 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); +} + +/** + * 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; + + while (1) { + int v, t; + + v = atomic_read(&sd->s_active); + if (unlikely(v < 0)) + return NULL; + + t = atomic_cmpxchg(&sd->s_active, v, v + 1); + if (likely(t == v)) { + rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); + return sd; + } + if (t < 0) + return NULL; + + cpu_relax(); + } +} + +/** + * 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; + + 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; + + 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->s_flags & SYSFS_FLAG_REMOVED); +} + +static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + struct sysfs_dirent *sd; + int is_dir; + + if (nd->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; + + 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. + */ + is_dir = (sysfs_type(sd) == SYSFS_DIR); + mutex_unlock(&sysfs_mutex); + if (is_dir) { + /* 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 (have_submounts(dentry)) + goto out_valid; + shrink_dcache_parent(dentry); + } + d_drop(dentry); + return 0; +} + +static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode) +{ + struct sysfs_dirent * sd = dentry->d_fsdata; + + sysfs_put(sd); + iput(inode); +} + +static const struct dentry_operations sysfs_dentry_ops = { + .d_revalidate = sysfs_dentry_revalidate, + .d_delete = sysfs_dentry_delete, + .d_iput = sysfs_dentry_iput, +}; + +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; + + 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 + * @parent_sd: parent sysfs_dirent + * + * This function is called when the caller is about to add or + * remove sysfs_dirent under @parent_sd. 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, + struct sysfs_dirent *parent_sd) +{ + memset(acxt, 0, sizeof(*acxt)); + acxt->parent_sd = parent_sd; + + 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 + * + * 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) +{ + struct sysfs_inode_attrs *ps_iattr; + int ret; + + if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) { + WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", + sysfs_ns_type(acxt->parent_sd)? "required": "invalid", + acxt->parent_sd->s_name, sd->s_name); + return -EINVAL; + } + + sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name); + sd->s_parent = sysfs_get(acxt->parent_sd); + + ret = sysfs_link_sibling(sd); + if (ret) + return ret; + + /* 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; + } + + return 0; +} + +/** + * sysfs_pathname - return full path to sysfs dirent + * @sd: sysfs_dirent whose path we want + * @path: caller allocated buffer + * + * Gives the name "/" to the sysfs_root entry; any path returned + * is relative to wherever sysfs is mounted. + * + * XXX: does no error checking on @path size + */ +static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) +{ + if (sd->s_parent) { + sysfs_pathname(sd->s_parent, path); + strcat(path, "/"); + } + strcat(path, sd->s_name); + return path; +} + +/** + * 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 : + strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), + sd->s_name)); + 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, + struct nameidata *nd) +{ + 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; + } + + /* 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_find_alias(inode); + if (!ret) { + d_set_d_op(dentry, &sysfs_dentry_ops); + dentry->d_fsdata = sysfs_get(sd); + d_add(dentry, inode); + } else { + d_move(ret, dentry); + iput(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) +{ + const char *dup_name = NULL; + 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 = dup_name = kstrdup(new_name, GFP_KERNEL); + if (!new_name) + goto out; + + dup_name = 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); + kfree(dup_name); + 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; + + 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++; + } + 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++; + } + mutex_lock(&sysfs_mutex); + 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); + filp->f_pos = pos->s_hash; + filp->private_data = sysfs_get(pos); + + mutex_unlock(&sysfs_mutex); + ret = filldir(dirent, name, len, filp->f_pos, ino, type); + mutex_lock(&sysfs_mutex); + if (ret < 0) + break; + } + mutex_unlock(&sysfs_mutex); + if ((filp->f_pos > 1) && !pos) { /* EOF */ + filp->f_pos = INT_MAX; + filp->private_data = NULL; + } + return 0; +} + + +const struct file_operations sysfs_dir_operations = { + .read = generic_read_dir, + .readdir = sysfs_readdir, + .release = sysfs_dir_release, + .llseek = generic_file_llseek, +}; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c new file mode 100644 index 00000000..00012e31 --- /dev/null +++ b/fs/sysfs/file.c @@ -0,0 +1,799 @@ +/* + * fs/sysfs/file.c - sysfs regular (text) file 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. + */ + +#include <linux/module.h> +#include <linux/kobject.h> +#include <linux/kallsyms.h> +#include <linux/slab.h> +#include <linux/fsnotify.h> +#include <linux/namei.h> +#include <linux/poll.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/limits.h> +#include <asm/uaccess.h> + +#include "sysfs.h" + +/* + * There's one sysfs_buffer for each open file and one + * sysfs_open_dirent for each sysfs_dirent with one or more open + * files. + * + * filp->private_data points to sysfs_buffer and + * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open + * is protected by sysfs_open_dirent_lock. + */ +static DEFINE_SPINLOCK(sysfs_open_dirent_lock); + +struct sysfs_open_dirent { + atomic_t refcnt; + atomic_t event; + wait_queue_head_t poll; + struct list_head buffers; /* goes through sysfs_buffer.list */ +}; + +struct sysfs_buffer { + size_t count; + loff_t pos; + char * page; + const struct sysfs_ops * ops; + struct mutex mutex; + int needs_read_fill; + int event; + struct list_head list; +}; + +/** + * fill_read_buffer - allocate and fill buffer from object. + * @dentry: dentry pointer. + * @buffer: data buffer for file. + * + * Allocate @buffer->page, if it hasn't been already, then call the + * kobject's show() method to fill the buffer with this attribute's + * data. + * This is called only once, on the file's first read unless an error + * is returned. + */ +static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) +{ + struct sysfs_dirent *attr_sd = dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + const struct sysfs_ops * ops = buffer->ops; + int ret = 0; + ssize_t count; + + if (!buffer->page) + buffer->page = (char *) get_zeroed_page(GFP_KERNEL); + if (!buffer->page) + return -ENOMEM; + + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + buffer->event = atomic_read(&attr_sd->s_attr.open->event); + count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); + + sysfs_put_active(attr_sd); + + /* + * The code works fine with PAGE_SIZE return but it's likely to + * indicate truncated result or overflow in normal use cases. + */ + if (count >= (ssize_t)PAGE_SIZE) { + print_symbol("fill_read_buffer: %s returned bad count\n", + (unsigned long)ops->show); + /* Try to struggle along */ + count = PAGE_SIZE - 1; + } + if (count >= 0) { + buffer->needs_read_fill = 0; + buffer->count = count; + } else { + ret = count; + } + return ret; +} + +/** + * sysfs_read_file - read an attribute. + * @file: file pointer. + * @buf: buffer to fill. + * @count: number of bytes to read. + * @ppos: starting offset in file. + * + * Userspace wants to read an attribute file. The attribute descriptor + * is in the file's ->d_fsdata. The target object is in the directory's + * ->d_fsdata. + * + * We call fill_read_buffer() to allocate and fill the buffer from the + * object's show() method exactly once (if the read is happening from + * the beginning of the file). That should fill the entire buffer with + * all the data the object has to offer for that attribute. + * We then call flush_read_buffer() to copy the buffer to userspace + * in the increments specified. + */ + +static ssize_t +sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + struct sysfs_buffer * buffer = file->private_data; + ssize_t retval = 0; + + mutex_lock(&buffer->mutex); + if (buffer->needs_read_fill || *ppos == 0) { + retval = fill_read_buffer(file->f_path.dentry,buffer); + if (retval) + goto out; + } + pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", + __func__, count, *ppos, buffer->page); + retval = simple_read_from_buffer(buf, count, ppos, buffer->page, + buffer->count); +out: + mutex_unlock(&buffer->mutex); + return retval; +} + +/** + * fill_write_buffer - copy buffer from userspace. + * @buffer: data buffer for file. + * @buf: data from user. + * @count: number of bytes in @userbuf. + * + * Allocate @buffer->page if it hasn't been already, then + * copy the user-supplied buffer into it. + */ + +static int +fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count) +{ + int error; + + if (!buffer->page) + buffer->page = (char *)get_zeroed_page(GFP_KERNEL); + if (!buffer->page) + return -ENOMEM; + + if (count >= PAGE_SIZE) + count = PAGE_SIZE - 1; + error = copy_from_user(buffer->page,buf,count); + buffer->needs_read_fill = 1; + /* if buf is assumed to contain a string, terminate it by \0, + so e.g. sscanf() can scan the string easily */ + buffer->page[count] = 0; + return error ? -EFAULT : count; +} + + +/** + * flush_write_buffer - push buffer to kobject. + * @dentry: dentry to the attribute + * @buffer: data buffer for file. + * @count: number of bytes + * + * Get the correct pointers for the kobject and the attribute we're + * dealing with, then call the store() method for the attribute, + * passing the buffer that we acquired in fill_write_buffer(). + */ + +static int +flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) +{ + struct sysfs_dirent *attr_sd = dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + const struct sysfs_ops * ops = buffer->ops; + int rc; + + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count); + + sysfs_put_active(attr_sd); + + return rc; +} + + +/** + * sysfs_write_file - write an attribute. + * @file: file pointer + * @buf: data to write + * @count: number of bytes + * @ppos: starting offset + * + * Similar to sysfs_read_file(), though working in the opposite direction. + * We allocate and fill the data from the user in fill_write_buffer(), + * then push it to the kobject in flush_write_buffer(). + * There is no easy way for us to know if userspace is only doing a partial + * write, so we don't support them. We expect the entire buffer to come + * on the first write. + * Hint: if you're writing a value, first read the file, modify only the + * the value you're changing, then write entire buffer back. + */ + +static ssize_t +sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +{ + struct sysfs_buffer * buffer = file->private_data; + ssize_t len; + + mutex_lock(&buffer->mutex); + len = fill_write_buffer(buffer, buf, count); + if (len > 0) + len = flush_write_buffer(file->f_path.dentry, buffer, len); + if (len > 0) + *ppos += len; + mutex_unlock(&buffer->mutex); + return len; +} + +/** + * sysfs_get_open_dirent - get or create sysfs_open_dirent + * @sd: target sysfs_dirent + * @buffer: sysfs_buffer for this instance of open + * + * If @sd->s_attr.open exists, increment its reference count; + * otherwise, create one. @buffer is chained to the buffers + * list. + * + * LOCKING: + * Kernel thread context (may sleep). + * + * RETURNS: + * 0 on success, -errno on failure. + */ +static int sysfs_get_open_dirent(struct sysfs_dirent *sd, + struct sysfs_buffer *buffer) +{ + struct sysfs_open_dirent *od, *new_od = NULL; + + retry: + spin_lock_irq(&sysfs_open_dirent_lock); + + if (!sd->s_attr.open && new_od) { + sd->s_attr.open = new_od; + new_od = NULL; + } + + od = sd->s_attr.open; + if (od) { + atomic_inc(&od->refcnt); + list_add_tail(&buffer->list, &od->buffers); + } + + spin_unlock_irq(&sysfs_open_dirent_lock); + + if (od) { + kfree(new_od); + return 0; + } + + /* not there, initialize a new one and retry */ + new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); + if (!new_od) + return -ENOMEM; + + atomic_set(&new_od->refcnt, 0); + atomic_set(&new_od->event, 1); + init_waitqueue_head(&new_od->poll); + INIT_LIST_HEAD(&new_od->buffers); + goto retry; +} + +/** + * sysfs_put_open_dirent - put sysfs_open_dirent + * @sd: target sysfs_dirent + * @buffer: associated sysfs_buffer + * + * Put @sd->s_attr.open and unlink @buffer from the buffers list. + * If reference count reaches zero, disassociate and free it. + * + * LOCKING: + * None. + */ +static void sysfs_put_open_dirent(struct sysfs_dirent *sd, + struct sysfs_buffer *buffer) +{ + struct sysfs_open_dirent *od = sd->s_attr.open; + unsigned long flags; + + spin_lock_irqsave(&sysfs_open_dirent_lock, flags); + + list_del(&buffer->list); + if (atomic_dec_and_test(&od->refcnt)) + sd->s_attr.open = NULL; + else + od = NULL; + + spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); + + kfree(od); +} + +static int sysfs_open_file(struct inode *inode, struct file *file) +{ + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + struct sysfs_buffer *buffer; + const struct sysfs_ops *ops; + int error = -EACCES; + + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active(attr_sd)) + return -ENODEV; + + /* every kobject with an attribute needs a ktype assigned */ + if (kobj->ktype && kobj->ktype->sysfs_ops) + ops = kobj->ktype->sysfs_ops; + else { + WARN(1, KERN_ERR "missing sysfs attribute operations for " + "kobject: %s\n", kobject_name(kobj)); + goto err_out; + } + + /* File needs write support. + * The inode's perms must say it's ok, + * and we must have a store method. + */ + if (file->f_mode & FMODE_WRITE) { + if (!(inode->i_mode & S_IWUGO) || !ops->store) + goto err_out; + } + + /* File needs read support. + * The inode's perms must say it's ok, and we there + * must be a show method for it. + */ + if (file->f_mode & FMODE_READ) { + if (!(inode->i_mode & S_IRUGO) || !ops->show) + goto err_out; + } + + /* No error? Great, allocate a buffer for the file, and store it + * it in file->private_data for easy access. + */ + error = -ENOMEM; + buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); + if (!buffer) + goto err_out; + + mutex_init(&buffer->mutex); + buffer->needs_read_fill = 1; + buffer->ops = ops; + file->private_data = buffer; + + /* make sure we have open dirent struct */ + error = sysfs_get_open_dirent(attr_sd, buffer); + if (error) + goto err_free; + + /* open succeeded, put active references */ + sysfs_put_active(attr_sd); + return 0; + + err_free: + kfree(buffer); + err_out: + sysfs_put_active(attr_sd); + return error; +} + +static int sysfs_release(struct inode *inode, struct file *filp) +{ + struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; + struct sysfs_buffer *buffer = filp->private_data; + + sysfs_put_open_dirent(sd, buffer); + + if (buffer->page) + free_page((unsigned long)buffer->page); + kfree(buffer); + + return 0; +} + +/* Sysfs attribute files are pollable. The idea is that you read + * the content and then you use 'poll' or 'select' to wait for + * the content to change. When the content changes (assuming the + * manager for the kobject supports notification), poll will + * return POLLERR|POLLPRI, and select will return the fd whether + * it is waiting for read, write, or exceptions. + * Once poll/select indicates that the value has changed, you + * need to close and re-open the file, or seek to 0 and read again. + * Reminder: this only works for attributes which actively support + * it, and it is not possible to test an attribute from userspace + * to see if it supports poll (Neither 'poll' nor 'select' return + * an appropriate error code). When in doubt, set a suitable timeout value. + */ +static unsigned int sysfs_poll(struct file *filp, poll_table *wait) +{ + struct sysfs_buffer * buffer = filp->private_data; + struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; + struct sysfs_open_dirent *od = attr_sd->s_attr.open; + + /* need parent for the kobj, grab both */ + if (!sysfs_get_active(attr_sd)) + goto trigger; + + poll_wait(filp, &od->poll, wait); + + sysfs_put_active(attr_sd); + + if (buffer->event != atomic_read(&od->event)) + goto trigger; + + return DEFAULT_POLLMASK; + + trigger: + buffer->needs_read_fill = 1; + return DEFAULT_POLLMASK|POLLERR|POLLPRI; +} + +void sysfs_notify_dirent(struct sysfs_dirent *sd) +{ + struct sysfs_open_dirent *od; + unsigned long flags; + + spin_lock_irqsave(&sysfs_open_dirent_lock, flags); + + od = sd->s_attr.open; + if (od) { + atomic_inc(&od->event); + wake_up_interruptible(&od->poll); + } + + spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); +} +EXPORT_SYMBOL_GPL(sysfs_notify_dirent); + +void sysfs_notify(struct kobject *k, const char *dir, const char *attr) +{ + struct sysfs_dirent *sd = k->sd; + + mutex_lock(&sysfs_mutex); + + if (sd && dir) + sd = sysfs_find_dirent(sd, NULL, dir); + if (sd && attr) + sd = sysfs_find_dirent(sd, NULL, attr); + if (sd) + sysfs_notify_dirent(sd); + + mutex_unlock(&sysfs_mutex); +} +EXPORT_SYMBOL_GPL(sysfs_notify); + +const struct file_operations sysfs_file_operations = { + .read = sysfs_read_file, + .write = sysfs_write_file, + .llseek = generic_file_llseek, + .open = sysfs_open_file, + .release = sysfs_release, + .poll = sysfs_poll, +}; + +int sysfs_attr_ns(struct kobject *kobj, const struct attribute *attr, + const void **pns) +{ + struct sysfs_dirent *dir_sd = kobj->sd; + const struct sysfs_ops *ops; + const void *ns = NULL; + int err; + + if (!dir_sd) { + WARN(1, KERN_ERR "sysfs: kobject %s without dirent\n", + kobject_name(kobj)); + return -ENOENT; + } + + err = 0; + if (!sysfs_ns_type(dir_sd)) + goto out; + + err = -EINVAL; + if (!kobj->ktype) + goto out; + ops = kobj->ktype->sysfs_ops; + if (!ops) + goto out; + if (!ops->namespace) + goto out; + + err = 0; + ns = ops->namespace(kobj, attr); +out: + if (err) { + WARN(1, KERN_ERR "missing sysfs namespace attribute operation for " + "kobject: %s\n", kobject_name(kobj)); + } + *pns = ns; + return err; +} + +int sysfs_add_file_mode(struct sysfs_dirent *dir_sd, + const struct attribute *attr, int type, umode_t amode) +{ + umode_t mode = (amode & S_IALLUGO) | S_IFREG; + struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *sd; + const void *ns; + int rc; + + rc = sysfs_attr_ns(dir_sd->s_dir.kobj, attr, &ns); + if (rc) + return rc; + + sd = sysfs_new_dirent(attr->name, mode, type); + if (!sd) + return -ENOMEM; + + sd->s_ns = ns; + sd->s_attr.attr = (void *)attr; + sysfs_dirent_init_lockdep(sd); + + sysfs_addrm_start(&acxt, dir_sd); + rc = sysfs_add_one(&acxt, sd); + sysfs_addrm_finish(&acxt); + + if (rc) + sysfs_put(sd); + + return rc; +} + + +int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, + int type) +{ + return sysfs_add_file_mode(dir_sd, attr, type, attr->mode); +} + + +/** + * sysfs_create_file - create an attribute file for an object. + * @kobj: object we're creating for. + * @attr: attribute descriptor. + */ + +int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) +{ + BUG_ON(!kobj || !kobj->sd || !attr); + + return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR); + +} + +int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) +{ + int err = 0; + int i; + + for (i = 0; ptr[i] && !err; i++) + err = sysfs_create_file(kobj, ptr[i]); + if (err) + while (--i >= 0) + sysfs_remove_file(kobj, ptr[i]); + return err; +} + +/** + * sysfs_add_file_to_group - add an attribute file to a pre-existing group. + * @kobj: object we're acting for. + * @attr: attribute descriptor. + * @group: group name. + */ +int sysfs_add_file_to_group(struct kobject *kobj, + const struct attribute *attr, const char *group) +{ + struct sysfs_dirent *dir_sd; + int error; + + if (group) + dir_sd = sysfs_get_dirent(kobj->sd, NULL, group); + else + dir_sd = sysfs_get(kobj->sd); + + if (!dir_sd) + return -ENOENT; + + error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); + sysfs_put(dir_sd); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); + +/** + * sysfs_chmod_file - update the modified mode value on an object attribute. + * @kobj: object we're acting for. + * @attr: attribute descriptor. + * @mode: file permissions. + * + */ +int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, + umode_t mode) +{ + struct sysfs_dirent *sd; + struct iattr newattrs; + const void *ns; + int rc; + + rc = sysfs_attr_ns(kobj, attr, &ns); + if (rc) + return rc; + + mutex_lock(&sysfs_mutex); + + rc = -ENOENT; + sd = sysfs_find_dirent(kobj->sd, ns, attr->name); + if (!sd) + goto out; + + newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); + newattrs.ia_valid = ATTR_MODE; + rc = sysfs_sd_setattr(sd, &newattrs); + + out: + mutex_unlock(&sysfs_mutex); + return rc; +} +EXPORT_SYMBOL_GPL(sysfs_chmod_file); + + +/** + * sysfs_remove_file - remove an object attribute. + * @kobj: object we're acting for. + * @attr: attribute descriptor. + * + * Hash the attribute name and kill the victim. + */ + +void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) +{ + const void *ns; + + if (sysfs_attr_ns(kobj, attr, &ns)) + return; + + sysfs_hash_and_remove(kobj->sd, ns, attr->name); +} + +void sysfs_remove_files(struct kobject * kobj, const struct attribute **ptr) +{ + int i; + for (i = 0; ptr[i]; i++) + sysfs_remove_file(kobj, ptr[i]); +} + +/** + * sysfs_remove_file_from_group - remove an attribute file from a group. + * @kobj: object we're acting for. + * @attr: attribute descriptor. + * @group: group name. + */ +void sysfs_remove_file_from_group(struct kobject *kobj, + const struct attribute *attr, const char *group) +{ + struct sysfs_dirent *dir_sd; + + if (group) + dir_sd = sysfs_get_dirent(kobj->sd, NULL, group); + else + dir_sd = sysfs_get(kobj->sd); + if (dir_sd) { + sysfs_hash_and_remove(dir_sd, NULL, attr->name); + sysfs_put(dir_sd); + } +} +EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); + +struct sysfs_schedule_callback_struct { + struct list_head workq_list; + struct kobject *kobj; + void (*func)(void *); + void *data; + struct module *owner; + struct work_struct work; +}; + +static struct workqueue_struct *sysfs_workqueue; +static DEFINE_MUTEX(sysfs_workq_mutex); +static LIST_HEAD(sysfs_workq); +static void sysfs_schedule_callback_work(struct work_struct *work) +{ + struct sysfs_schedule_callback_struct *ss = container_of(work, + struct sysfs_schedule_callback_struct, work); + + (ss->func)(ss->data); + kobject_put(ss->kobj); + module_put(ss->owner); + mutex_lock(&sysfs_workq_mutex); + list_del(&ss->workq_list); + mutex_unlock(&sysfs_workq_mutex); + kfree(ss); +} + +/** + * sysfs_schedule_callback - helper to schedule a callback for a kobject + * @kobj: object we're acting for. + * @func: callback function to invoke later. + * @data: argument to pass to @func. + * @owner: module owning the callback code + * + * sysfs attribute methods must not unregister themselves or their parent + * kobject (which would amount to the same thing). Attempts to do so will + * deadlock, since unregistration is mutually exclusive with driver + * callbacks. + * + * Instead methods can call this routine, which will attempt to allocate + * and schedule a workqueue request to call back @func with @data as its + * argument in the workqueue's process context. @kobj will be pinned + * until @func returns. + * + * Returns 0 if the request was submitted, -ENOMEM if storage could not + * be allocated, -ENODEV if a reference to @owner isn't available, + * -EAGAIN if a callback has already been scheduled for @kobj. + */ +int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), + void *data, struct module *owner) +{ + struct sysfs_schedule_callback_struct *ss, *tmp; + + if (!try_module_get(owner)) + return -ENODEV; + + mutex_lock(&sysfs_workq_mutex); + list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) + if (ss->kobj == kobj) { + module_put(owner); + mutex_unlock(&sysfs_workq_mutex); + return -EAGAIN; + } + mutex_unlock(&sysfs_workq_mutex); + + if (sysfs_workqueue == NULL) { + sysfs_workqueue = create_singlethread_workqueue("sysfsd"); + if (sysfs_workqueue == NULL) { + module_put(owner); + return -ENOMEM; + } + } + + ss = kmalloc(sizeof(*ss), GFP_KERNEL); + if (!ss) { + module_put(owner); + return -ENOMEM; + } + kobject_get(kobj); + ss->kobj = kobj; + ss->func = func; + ss->data = data; + ss->owner = owner; + INIT_WORK(&ss->work, sysfs_schedule_callback_work); + INIT_LIST_HEAD(&ss->workq_list); + mutex_lock(&sysfs_workq_mutex); + list_add_tail(&ss->workq_list, &sysfs_workq); + mutex_unlock(&sysfs_workq_mutex); + queue_work(sysfs_workqueue, &ss->work); + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_schedule_callback); + + +EXPORT_SYMBOL_GPL(sysfs_create_file); +EXPORT_SYMBOL_GPL(sysfs_remove_file); +EXPORT_SYMBOL_GPL(sysfs_remove_files); +EXPORT_SYMBOL_GPL(sysfs_create_files); diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c new file mode 100644 index 00000000..2df555c6 --- /dev/null +++ b/fs/sysfs/group.c @@ -0,0 +1,211 @@ +/* + * fs/sysfs/group.c - Operations for adding/removing multiple files at once. + * + * Copyright (c) 2003 Patrick Mochel + * Copyright (c) 2003 Open Source Development Lab + * + * This file is released undert the GPL v2. + * + */ + +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/dcache.h> +#include <linux/namei.h> +#include <linux/err.h> +#include "sysfs.h" + + +static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj, + const struct attribute_group *grp) +{ + struct attribute *const* attr; + int i; + + for (i = 0, attr = grp->attrs; *attr; i++, attr++) + sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name); +} + +static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj, + const struct attribute_group *grp, int update) +{ + struct attribute *const* attr; + int error = 0, i; + + for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) { + umode_t mode = 0; + + /* in update mode, we're changing the permissions or + * visibility. Do this by first removing then + * re-adding (if required) the file */ + if (update) + sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name); + if (grp->is_visible) { + mode = grp->is_visible(kobj, *attr, i); + if (!mode) + continue; + } + error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR, + (*attr)->mode | mode); + if (unlikely(error)) + break; + } + if (error) + remove_files(dir_sd, kobj, grp); + return error; +} + + +static int internal_create_group(struct kobject *kobj, int update, + const struct attribute_group *grp) +{ + struct sysfs_dirent *sd; + int error; + + BUG_ON(!kobj || (!update && !kobj->sd)); + + /* Updates may happen before the object has been instantiated */ + if (unlikely(update && !kobj->sd)) + return -EINVAL; + if (!grp->attrs) { + WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n", + kobj->name, grp->name ? "" : grp->name); + return -EINVAL; + } + if (grp->name) { + error = sysfs_create_subdir(kobj, grp->name, &sd); + if (error) + return error; + } else + sd = kobj->sd; + sysfs_get(sd); + error = create_files(sd, kobj, grp, update); + if (error) { + if (grp->name) + sysfs_remove_subdir(sd); + } + sysfs_put(sd); + return error; +} + +/** + * sysfs_create_group - given a directory kobject, create an attribute group + * @kobj: The kobject to create the group on + * @grp: The attribute group to create + * + * This function creates a group for the first time. It will explicitly + * warn and error if any of the attribute files being created already exist. + * + * Returns 0 on success or error. + */ +int sysfs_create_group(struct kobject *kobj, + const struct attribute_group *grp) +{ + return internal_create_group(kobj, 0, grp); +} + +/** + * sysfs_update_group - given a directory kobject, update an attribute group + * @kobj: The kobject to update the group on + * @grp: The attribute group to update + * + * This function updates an attribute group. Unlike + * sysfs_create_group(), it will explicitly not warn or error if any + * of the attribute files being created already exist. Furthermore, + * if the visibility of the files has changed through the is_visible() + * callback, it will update the permissions and add or remove the + * relevant files. + * + * The primary use for this function is to call it after making a change + * that affects group visibility. + * + * Returns 0 on success or error. + */ +int sysfs_update_group(struct kobject *kobj, + const struct attribute_group *grp) +{ + return internal_create_group(kobj, 1, grp); +} + + + +void sysfs_remove_group(struct kobject * kobj, + const struct attribute_group * grp) +{ + struct sysfs_dirent *dir_sd = kobj->sd; + struct sysfs_dirent *sd; + + if (grp->name) { + sd = sysfs_get_dirent(dir_sd, NULL, grp->name); + if (!sd) { + WARN(!sd, KERN_WARNING "sysfs group %p not found for " + "kobject '%s'\n", grp, kobject_name(kobj)); + return; + } + } else + sd = sysfs_get(dir_sd); + + remove_files(sd, kobj, grp); + if (grp->name) + sysfs_remove_subdir(sd); + + sysfs_put(sd); +} + +/** + * sysfs_merge_group - merge files into a pre-existing attribute group. + * @kobj: The kobject containing the group. + * @grp: The files to create and the attribute group they belong to. + * + * This function returns an error if the group doesn't exist or any of the + * files already exist in that group, in which case none of the new files + * are created. + */ +int sysfs_merge_group(struct kobject *kobj, + const struct attribute_group *grp) +{ + struct sysfs_dirent *dir_sd; + int error = 0; + struct attribute *const *attr; + int i; + + dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name); + if (!dir_sd) + return -ENOENT; + + for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr)) + error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR); + if (error) { + while (--i >= 0) + sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name); + } + sysfs_put(dir_sd); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_merge_group); + +/** + * sysfs_unmerge_group - remove files from a pre-existing attribute group. + * @kobj: The kobject containing the group. + * @grp: The files to remove and the attribute group they belong to. + */ +void sysfs_unmerge_group(struct kobject *kobj, + const struct attribute_group *grp) +{ + struct sysfs_dirent *dir_sd; + struct attribute *const *attr; + + dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name); + if (dir_sd) { + for (attr = grp->attrs; *attr; ++attr) + sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name); + sysfs_put(dir_sd); + } +} +EXPORT_SYMBOL_GPL(sysfs_unmerge_group); + + +EXPORT_SYMBOL_GPL(sysfs_create_group); +EXPORT_SYMBOL_GPL(sysfs_update_group); +EXPORT_SYMBOL_GPL(sysfs_remove_group); diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c new file mode 100644 index 00000000..feb2d693 --- /dev/null +++ b/fs/sysfs/inode.c @@ -0,0 +1,356 @@ +/* + * fs/sysfs/inode.c - basic sysfs inode and dentry operations + * + * 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/pagemap.h> +#include <linux/namei.h> +#include <linux/backing-dev.h> +#include <linux/capability.h> +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/xattr.h> +#include <linux/security.h> +#include "sysfs.h" + +extern struct super_block * sysfs_sb; + +static const struct address_space_operations sysfs_aops = { + .readpage = simple_readpage, + .write_begin = simple_write_begin, + .write_end = simple_write_end, +}; + +static struct backing_dev_info sysfs_backing_dev_info = { + .name = "sysfs", + .ra_pages = 0, /* No readahead */ + .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, +}; + +static const struct inode_operations sysfs_inode_operations ={ + .permission = sysfs_permission, + .setattr = sysfs_setattr, + .getattr = sysfs_getattr, + .setxattr = sysfs_setxattr, +}; + +int __init sysfs_inode_init(void) +{ + return bdi_init(&sysfs_backing_dev_info); +} + +static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) +{ + struct sysfs_inode_attrs *attrs; + struct iattr *iattrs; + + attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL); + if (!attrs) + return NULL; + iattrs = &attrs->ia_iattr; + + /* assign default attributes */ + iattrs->ia_mode = sd->s_mode; + iattrs->ia_uid = 0; + iattrs->ia_gid = 0; + iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME; + + return attrs; +} + +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) +{ + struct sysfs_inode_attrs *sd_attrs; + struct iattr *iattrs; + unsigned int ia_valid = iattr->ia_valid; + + sd_attrs = sd->s_iattr; + + if (!sd_attrs) { + /* setting attributes for the first time, allocate now */ + sd_attrs = sysfs_init_inode_attrs(sd); + if (!sd_attrs) + return -ENOMEM; + sd->s_iattr = sd_attrs; + } + /* attributes were changed at least once in past */ + iattrs = &sd_attrs->ia_iattr; + + if (ia_valid & ATTR_UID) + iattrs->ia_uid = iattr->ia_uid; + if (ia_valid & ATTR_GID) + iattrs->ia_gid = iattr->ia_gid; + if (ia_valid & ATTR_ATIME) + iattrs->ia_atime = iattr->ia_atime; + if (ia_valid & ATTR_MTIME) + iattrs->ia_mtime = iattr->ia_mtime; + if (ia_valid & ATTR_CTIME) + iattrs->ia_ctime = iattr->ia_ctime; + if (ia_valid & ATTR_MODE) { + umode_t mode = iattr->ia_mode; + iattrs->ia_mode = sd->s_mode = mode; + } + return 0; +} + +int sysfs_setattr(struct dentry *dentry, struct iattr *iattr) +{ + struct inode *inode = dentry->d_inode; + struct sysfs_dirent *sd = dentry->d_fsdata; + int error; + + if (!sd) + return -EINVAL; + + mutex_lock(&sysfs_mutex); + error = inode_change_ok(inode, iattr); + if (error) + goto out; + + error = sysfs_sd_setattr(sd, iattr); + if (error) + goto out; + + /* this ignores size changes */ + setattr_copy(inode, iattr); + +out: + mutex_unlock(&sysfs_mutex); + return error; +} + +static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len) +{ + struct sysfs_inode_attrs *iattrs; + void *old_secdata; + size_t old_secdata_len; + + if (!sd->s_iattr) { + sd->s_iattr = sysfs_init_inode_attrs(sd); + if (!sd->s_iattr) + return -ENOMEM; + } + + iattrs = sd->s_iattr; + old_secdata = iattrs->ia_secdata; + old_secdata_len = iattrs->ia_secdata_len; + + iattrs->ia_secdata = *secdata; + iattrs->ia_secdata_len = *secdata_len; + + *secdata = old_secdata; + *secdata_len = old_secdata_len; + return 0; +} + +int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + void *secdata; + int error; + u32 secdata_len = 0; + + if (!sd) + return -EINVAL; + + if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { + const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; + error = security_inode_setsecurity(dentry->d_inode, suffix, + value, size, flags); + if (error) + goto out; + error = security_inode_getsecctx(dentry->d_inode, + &secdata, &secdata_len); + if (error) + goto out; + + mutex_lock(&sysfs_mutex); + error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len); + mutex_unlock(&sysfs_mutex); + + if (secdata) + security_release_secctx(secdata, secdata_len); + } else + return -EINVAL; +out: + return error; +} + +static inline void set_default_inode_attr(struct inode * inode, umode_t mode) +{ + inode->i_mode = mode; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; +} + +static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) +{ + inode->i_uid = iattr->ia_uid; + inode->i_gid = iattr->ia_gid; + inode->i_atime = iattr->ia_atime; + inode->i_mtime = iattr->ia_mtime; + inode->i_ctime = iattr->ia_ctime; +} + +static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode) +{ + struct sysfs_inode_attrs *iattrs = sd->s_iattr; + + inode->i_mode = sd->s_mode; + if (iattrs) { + /* sysfs_dirent has non-default attributes + * get them from persistent copy in sysfs_dirent + */ + set_inode_attr(inode, &iattrs->ia_iattr); + security_inode_notifysecctx(inode, + iattrs->ia_secdata, + iattrs->ia_secdata_len); + } + + if (sysfs_type(sd) == SYSFS_DIR) + set_nlink(inode, sd->s_dir.subdirs + 2); +} + +int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct inode *inode = dentry->d_inode; + + mutex_lock(&sysfs_mutex); + sysfs_refresh_inode(sd, inode); + mutex_unlock(&sysfs_mutex); + + generic_fillattr(inode, stat); + return 0; +} + +static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) +{ + struct bin_attribute *bin_attr; + + inode->i_private = sysfs_get(sd); + inode->i_mapping->a_ops = &sysfs_aops; + inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; + inode->i_op = &sysfs_inode_operations; + + set_default_inode_attr(inode, sd->s_mode); + sysfs_refresh_inode(sd, inode); + + /* initialize inode according to type */ + switch (sysfs_type(sd)) { + case SYSFS_DIR: + inode->i_op = &sysfs_dir_inode_operations; + inode->i_fop = &sysfs_dir_operations; + break; + case SYSFS_KOBJ_ATTR: + inode->i_size = PAGE_SIZE; + inode->i_fop = &sysfs_file_operations; + break; + case SYSFS_KOBJ_BIN_ATTR: + bin_attr = sd->s_bin_attr.bin_attr; + inode->i_size = bin_attr->size; + inode->i_fop = &bin_fops; + break; + case SYSFS_KOBJ_LINK: + inode->i_op = &sysfs_symlink_inode_operations; + break; + default: + BUG(); + } + + unlock_new_inode(inode); +} + +/** + * sysfs_get_inode - get inode for sysfs_dirent + * @sb: super block + * @sd: sysfs_dirent to allocate inode for + * + * Get inode for @sd. If such inode doesn't exist, a new inode + * is allocated and basics are initialized. New inode is + * returned locked. + * + * LOCKING: + * Kernel thread context (may sleep). + * + * RETURNS: + * Pointer to allocated inode on success, NULL on failure. + */ +struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd) +{ + struct inode *inode; + + inode = iget_locked(sb, sd->s_ino); + if (inode && (inode->i_state & I_NEW)) + sysfs_init_inode(sd, inode); + + return inode; +} + +/* + * The sysfs_dirent serves as both an inode and a directory entry for sysfs. + * To prevent the sysfs inode numbers from being freed prematurely we take a + * reference to sysfs_dirent from the sysfs inode. A + * super_operations.evict_inode() implementation is needed to drop that + * reference upon inode destruction. + */ +void sysfs_evict_inode(struct inode *inode) +{ + struct sysfs_dirent *sd = inode->i_private; + + truncate_inode_pages(&inode->i_data, 0); + end_writeback(inode); + sysfs_put(sd); +} + +int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const char *name) +{ + struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *sd; + + if (!dir_sd) { + WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n", + name); + return -ENOENT; + } + + sysfs_addrm_start(&acxt, dir_sd); + + sd = sysfs_find_dirent(dir_sd, ns, name); + if (sd) + sysfs_remove_one(&acxt, sd); + + sysfs_addrm_finish(&acxt); + + if (sd) + return 0; + else + return -ENOENT; +} + +int sysfs_permission(struct inode *inode, int mask) +{ + struct sysfs_dirent *sd; + + if (mask & MAY_NOT_BLOCK) + return -ECHILD; + + sd = inode->i_private; + + mutex_lock(&sysfs_mutex); + sysfs_refresh_inode(sd, inode); + mutex_unlock(&sysfs_mutex); + + return generic_permission(inode, mask); +} diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c new file mode 100644 index 00000000..52c3bdb6 --- /dev/null +++ b/fs/sysfs/mount.c @@ -0,0 +1,200 @@ +/* + * fs/sysfs/symlink.c - operations for initializing and mounting sysfs + * + * 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. + */ + +#define DEBUG + +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/pagemap.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/magic.h> +#include <linux/slab.h> + +#include "sysfs.h" + + +static struct vfsmount *sysfs_mnt; +struct kmem_cache *sysfs_dir_cachep; + +static const struct super_operations sysfs_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, + .evict_inode = sysfs_evict_inode, +}; + +struct sysfs_dirent sysfs_root = { + .s_name = "", + .s_count = ATOMIC_INIT(1), + .s_flags = SYSFS_DIR | (KOBJ_NS_TYPE_NONE << SYSFS_NS_TYPE_SHIFT), + .s_mode = S_IFDIR | S_IRUGO | S_IXUGO, + .s_ino = 1, +}; + +static int sysfs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + struct dentry *root; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = SYSFS_MAGIC; + sb->s_op = &sysfs_ops; + sb->s_time_gran = 1; + + /* get root inode, initialize and unlock it */ + mutex_lock(&sysfs_mutex); + inode = sysfs_get_inode(sb, &sysfs_root); + mutex_unlock(&sysfs_mutex); + if (!inode) { + pr_debug("sysfs: could not get root inode\n"); + return -ENOMEM; + } + + /* instantiate and link root dentry */ + root = d_make_root(inode); + if (!root) { + pr_debug("%s: could not get root dentry!\n",__func__); + return -ENOMEM; + } + root->d_fsdata = &sysfs_root; + sb->s_root = root; + return 0; +} + +static int sysfs_test_super(struct super_block *sb, void *data) +{ + struct sysfs_super_info *sb_info = sysfs_info(sb); + struct sysfs_super_info *info = data; + enum kobj_ns_type type; + int found = 1; + + for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) { + if (sb_info->ns[type] != info->ns[type]) + found = 0; + } + return found; +} + +static int sysfs_set_super(struct super_block *sb, void *data) +{ + int error; + error = set_anon_super(sb, data); + if (!error) + sb->s_fs_info = data; + return error; +} + +static void free_sysfs_super_info(struct sysfs_super_info *info) +{ + int type; + for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) + kobj_ns_drop(type, info->ns[type]); + kfree(info); +} + +static struct dentry *sysfs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + struct sysfs_super_info *info; + enum kobj_ns_type type; + struct super_block *sb; + int error; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) + info->ns[type] = kobj_ns_grab_current(type); + + sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info); + if (IS_ERR(sb) || sb->s_fs_info != info) + free_sysfs_super_info(info); + if (IS_ERR(sb)) + return ERR_CAST(sb); + if (!sb->s_root) { + sb->s_flags = flags; + error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0); + if (error) { + deactivate_locked_super(sb); + return ERR_PTR(error); + } + sb->s_flags |= MS_ACTIVE; + } + + return dget(sb->s_root); +} + +static void sysfs_kill_sb(struct super_block *sb) +{ + struct sysfs_super_info *info = sysfs_info(sb); + /* Remove the superblock from fs_supers/s_instances + * so we can't find it, before freeing sysfs_super_info. + */ + kill_anon_super(sb); + free_sysfs_super_info(info); +} + +static struct file_system_type sysfs_fs_type = { + .name = "sysfs", + .mount = sysfs_mount, + .kill_sb = sysfs_kill_sb, +}; + +int __init sysfs_init(void) +{ + int err = -ENOMEM; + + sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache", + sizeof(struct sysfs_dirent), + 0, 0, NULL); + if (!sysfs_dir_cachep) + goto out; + + err = sysfs_inode_init(); + if (err) + goto out_err; + + err = register_filesystem(&sysfs_fs_type); + if (!err) { + sysfs_mnt = kern_mount(&sysfs_fs_type); + if (IS_ERR(sysfs_mnt)) { + printk(KERN_ERR "sysfs: could not mount!\n"); + err = PTR_ERR(sysfs_mnt); + sysfs_mnt = NULL; + unregister_filesystem(&sysfs_fs_type); + goto out_err; + } + } else + goto out_err; +out: + return err; +out_err: + kmem_cache_destroy(sysfs_dir_cachep); + sysfs_dir_cachep = NULL; + goto out; +} + +#undef sysfs_get +struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) +{ + return __sysfs_get(sd); +} +EXPORT_SYMBOL_GPL(sysfs_get); + +#undef sysfs_put +void sysfs_put(struct sysfs_dirent *sd) +{ + __sysfs_put(sd); +} +EXPORT_SYMBOL_GPL(sysfs_put); diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c new file mode 100644 index 00000000..a7ac78f8 --- /dev/null +++ b/fs/sysfs/symlink.c @@ -0,0 +1,307 @@ +/* + * fs/sysfs/symlink.c - sysfs symlink 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. + */ + +#include <linux/fs.h> +#include <linux/gfp.h> +#include <linux/mount.h> +#include <linux/module.h> +#include <linux/kobject.h> +#include <linux/namei.h> +#include <linux/mutex.h> +#include <linux/security.h> + +#include "sysfs.h" + +static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target, + const char *name, int warn) +{ + struct sysfs_dirent *parent_sd = NULL; + struct sysfs_dirent *target_sd = NULL; + struct sysfs_dirent *sd = NULL; + struct sysfs_addrm_cxt acxt; + enum kobj_ns_type ns_type; + int error; + + BUG_ON(!name); + + if (!kobj) + parent_sd = &sysfs_root; + else + parent_sd = kobj->sd; + + error = -EFAULT; + if (!parent_sd) + goto out_put; + + /* target->sd can go away beneath us but is protected with + * sysfs_assoc_lock. Fetch target_sd from it. + */ + spin_lock(&sysfs_assoc_lock); + if (target->sd) + target_sd = sysfs_get(target->sd); + spin_unlock(&sysfs_assoc_lock); + + error = -ENOENT; + if (!target_sd) + goto out_put; + + error = -ENOMEM; + sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); + if (!sd) + goto out_put; + + ns_type = sysfs_ns_type(parent_sd); + if (ns_type) + sd->s_ns = target->ktype->namespace(target); + sd->s_symlink.target_sd = target_sd; + target_sd = NULL; /* reference is now owned by the symlink */ + + sysfs_addrm_start(&acxt, parent_sd); + /* Symlinks must be between directories with the same ns_type */ + if (!ns_type || + (ns_type == sysfs_ns_type(sd->s_symlink.target_sd->s_parent))) { + if (warn) + error = sysfs_add_one(&acxt, sd); + else + error = __sysfs_add_one(&acxt, sd); + } else { + error = -EINVAL; + WARN(1, KERN_WARNING + "sysfs: symlink across ns_types %s/%s -> %s/%s\n", + parent_sd->s_name, + sd->s_name, + sd->s_symlink.target_sd->s_parent->s_name, + sd->s_symlink.target_sd->s_name); + } + sysfs_addrm_finish(&acxt); + + if (error) + goto out_put; + + return 0; + + out_put: + sysfs_put(target_sd); + sysfs_put(sd); + return error; +} + +/** + * sysfs_create_link - create symlink between two objects. + * @kobj: object whose directory we're creating the link in. + * @target: object we're pointing to. + * @name: name of the symlink. + */ +int sysfs_create_link(struct kobject *kobj, struct kobject *target, + const char *name) +{ + return sysfs_do_create_link(kobj, target, name, 1); +} + +/** + * sysfs_create_link_nowarn - create symlink between two objects. + * @kobj: object whose directory we're creating the link in. + * @target: object we're pointing to. + * @name: name of the symlink. + * + * This function does the same as sysf_create_link(), but it + * doesn't warn if the link already exists. + */ +int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target, + const char *name) +{ + return sysfs_do_create_link(kobj, target, name, 0); +} + +/** + * sysfs_delete_link - remove symlink in object's directory. + * @kobj: object we're acting for. + * @targ: object we're pointing to. + * @name: name of the symlink to remove. + * + * Unlike sysfs_remove_link sysfs_delete_link has enough information + * to successfully delete symlinks in tagged directories. + */ +void sysfs_delete_link(struct kobject *kobj, struct kobject *targ, + const char *name) +{ + const void *ns = NULL; + spin_lock(&sysfs_assoc_lock); + if (targ->sd && sysfs_ns_type(kobj->sd)) + ns = targ->sd->s_ns; + spin_unlock(&sysfs_assoc_lock); + sysfs_hash_and_remove(kobj->sd, ns, name); +} + +/** + * sysfs_remove_link - remove symlink in object's directory. + * @kobj: object we're acting for. + * @name: name of the symlink to remove. + */ + +void sysfs_remove_link(struct kobject * kobj, const char * name) +{ + struct sysfs_dirent *parent_sd = NULL; + + if (!kobj) + parent_sd = &sysfs_root; + else + parent_sd = kobj->sd; + + sysfs_hash_and_remove(parent_sd, NULL, name); +} + +/** + * sysfs_rename_link - rename symlink in object's directory. + * @kobj: object we're acting for. + * @targ: object we're pointing to. + * @old: previous name of the symlink. + * @new: new name of the symlink. + * + * A helper function for the common rename symlink idiom. + */ +int sysfs_rename_link(struct kobject *kobj, struct kobject *targ, + const char *old, const char *new) +{ + struct sysfs_dirent *parent_sd, *sd = NULL; + const void *old_ns = NULL, *new_ns = NULL; + int result; + + if (!kobj) + parent_sd = &sysfs_root; + else + parent_sd = kobj->sd; + + if (targ->sd) + old_ns = targ->sd->s_ns; + + result = -ENOENT; + sd = sysfs_get_dirent(parent_sd, old_ns, old); + if (!sd) + goto out; + + result = -EINVAL; + if (sysfs_type(sd) != SYSFS_KOBJ_LINK) + goto out; + if (sd->s_symlink.target_sd->s_dir.kobj != targ) + goto out; + + if (sysfs_ns_type(parent_sd)) + new_ns = targ->ktype->namespace(targ); + + result = sysfs_rename(sd, parent_sd, new_ns, new); + +out: + sysfs_put(sd); + return result; +} + +static int sysfs_get_target_path(struct sysfs_dirent *parent_sd, + struct sysfs_dirent *target_sd, char *path) +{ + struct sysfs_dirent *base, *sd; + char *s = path; + int len = 0; + + /* go up to the root, stop at the base */ + base = parent_sd; + while (base->s_parent) { + sd = target_sd->s_parent; + while (sd->s_parent && base != sd) + sd = sd->s_parent; + + if (base == sd) + break; + + strcpy(s, "../"); + s += 3; + base = base->s_parent; + } + + /* determine end of target string for reverse fillup */ + sd = target_sd; + while (sd->s_parent && sd != base) { + len += strlen(sd->s_name) + 1; + sd = sd->s_parent; + } + + /* check limits */ + if (len < 2) + return -EINVAL; + len--; + if ((s - path) + len > PATH_MAX) + return -ENAMETOOLONG; + + /* reverse fillup of target string from target to base */ + sd = target_sd; + while (sd->s_parent && sd != base) { + int slen = strlen(sd->s_name); + + len -= slen; + strncpy(s + len, sd->s_name, slen); + if (len) + s[--len] = '/'; + + sd = sd->s_parent; + } + + return 0; +} + +static int sysfs_getlink(struct dentry *dentry, char * path) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_dirent *parent_sd = sd->s_parent; + struct sysfs_dirent *target_sd = sd->s_symlink.target_sd; + int error; + + mutex_lock(&sysfs_mutex); + error = sysfs_get_target_path(parent_sd, target_sd, path); + mutex_unlock(&sysfs_mutex); + + return error; +} + +static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + int error = -ENOMEM; + unsigned long page = get_zeroed_page(GFP_KERNEL); + if (page) { + error = sysfs_getlink(dentry, (char *) page); + if (error < 0) + free_page((unsigned long)page); + } + nd_set_link(nd, error ? ERR_PTR(error) : (char *)page); + return NULL; +} + +static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) +{ + char *page = nd_get_link(nd); + if (!IS_ERR(page)) + free_page((unsigned long)page); +} + +const struct inode_operations sysfs_symlink_inode_operations = { + .setxattr = sysfs_setxattr, + .readlink = generic_readlink, + .follow_link = sysfs_follow_link, + .put_link = sysfs_put_link, + .setattr = sysfs_setattr, + .getattr = sysfs_getattr, + .permission = sysfs_permission, +}; + + +EXPORT_SYMBOL_GPL(sysfs_create_link); +EXPORT_SYMBOL_GPL(sysfs_remove_link); +EXPORT_SYMBOL_GPL(sysfs_rename_link); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h new file mode 100644 index 00000000..661a9639 --- /dev/null +++ b/fs/sysfs/sysfs.h @@ -0,0 +1,241 @@ +/* + * fs/sysfs/sysfs.h - sysfs internal header file + * + * 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. + */ + +#include <linux/lockdep.h> +#include <linux/kobject_ns.h> +#include <linux/fs.h> +#include <linux/rbtree.h> + +struct sysfs_open_dirent; + +/* type-specific structures for sysfs_dirent->s_* union members */ +struct sysfs_elem_dir { + struct kobject *kobj; + + unsigned long subdirs; + /* children rbtree starts here and goes through sd->s_rb */ + struct rb_root children; +}; + +struct sysfs_elem_symlink { + struct sysfs_dirent *target_sd; +}; + +struct sysfs_elem_attr { + struct attribute *attr; + struct sysfs_open_dirent *open; +}; + +struct sysfs_elem_bin_attr { + struct bin_attribute *bin_attr; + struct hlist_head buffers; +}; + +struct sysfs_inode_attrs { + struct iattr ia_iattr; + void *ia_secdata; + u32 ia_secdata_len; +}; + +/* + * sysfs_dirent - the building block of sysfs hierarchy. Each and + * every sysfs node is represented by single sysfs_dirent. + * + * As long as s_count reference is held, the sysfs_dirent itself is + * accessible. Dereferencing s_elem or any other outer entity + * requires s_active reference. + */ +struct sysfs_dirent { + atomic_t s_count; + atomic_t s_active; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif + struct sysfs_dirent *s_parent; + const char *s_name; + + struct rb_node s_rb; + + union { + struct completion *completion; + struct sysfs_dirent *removed_list; + } u; + + const void *s_ns; /* namespace tag */ + unsigned int s_hash; /* ns + name hash */ + union { + struct sysfs_elem_dir s_dir; + struct sysfs_elem_symlink s_symlink; + struct sysfs_elem_attr s_attr; + struct sysfs_elem_bin_attr s_bin_attr; + }; + + unsigned short s_flags; + umode_t s_mode; + unsigned int s_ino; + struct sysfs_inode_attrs *s_iattr; +}; + +#define SD_DEACTIVATED_BIAS INT_MIN + +#define SYSFS_TYPE_MASK 0x00ff +#define SYSFS_DIR 0x0001 +#define SYSFS_KOBJ_ATTR 0x0002 +#define SYSFS_KOBJ_BIN_ATTR 0x0004 +#define SYSFS_KOBJ_LINK 0x0008 +#define SYSFS_COPY_NAME (SYSFS_DIR | SYSFS_KOBJ_LINK) +#define SYSFS_ACTIVE_REF (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR) + +/* identify any namespace tag on sysfs_dirents */ +#define SYSFS_NS_TYPE_MASK 0xf00 +#define SYSFS_NS_TYPE_SHIFT 8 + +#define SYSFS_FLAG_MASK ~(SYSFS_NS_TYPE_MASK|SYSFS_TYPE_MASK) +#define SYSFS_FLAG_REMOVED 0x02000 + +static inline unsigned int sysfs_type(struct sysfs_dirent *sd) +{ + return sd->s_flags & SYSFS_TYPE_MASK; +} + +/* + * Return any namespace tags on this dirent. + * enum kobj_ns_type is defined in linux/kobject.h + */ +static inline enum kobj_ns_type sysfs_ns_type(struct sysfs_dirent *sd) +{ + return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT; +} + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +#define sysfs_dirent_init_lockdep(sd) \ +do { \ + struct attribute *attr = sd->s_attr.attr; \ + struct lock_class_key *key = attr->key; \ + if (!key) \ + key = &attr->skey; \ + \ + lockdep_init_map(&sd->dep_map, "s_active", key, 0); \ +} while(0) +#else +#define sysfs_dirent_init_lockdep(sd) do {} while(0) +#endif + +/* + * Context structure to be used while adding/removing nodes. + */ +struct sysfs_addrm_cxt { + struct sysfs_dirent *parent_sd; + struct sysfs_dirent *removed; +}; + +/* + * mount.c + */ + +/* + * Each sb is associated with a set of namespace tags (i.e. + * the network namespace of the task which mounted this sysfs + * instance). + */ +struct sysfs_super_info { + void *ns[KOBJ_NS_TYPES]; +}; +#define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info)) +extern struct sysfs_dirent sysfs_root; +extern struct kmem_cache *sysfs_dir_cachep; + +/* + * dir.c + */ +extern struct mutex sysfs_mutex; +extern spinlock_t sysfs_assoc_lock; + +extern const struct file_operations sysfs_dir_operations; +extern const struct inode_operations sysfs_dir_inode_operations; + +struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd); +struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd); +void sysfs_put_active(struct sysfs_dirent *sd); +void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, + struct sysfs_dirent *parent_sd); +int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd); +int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd); +void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd); +void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt); + +struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, + const void *ns, + const unsigned char *name); +struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, + const void *ns, + const unsigned char *name); +struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type); + +void release_sysfs_dirent(struct sysfs_dirent *sd); + +int sysfs_create_subdir(struct kobject *kobj, const char *name, + struct sysfs_dirent **p_sd); +void sysfs_remove_subdir(struct sysfs_dirent *sd); + +int sysfs_rename(struct sysfs_dirent *sd, + struct sysfs_dirent *new_parent_sd, const void *ns, const char *new_name); + +static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd) +{ + if (sd) { + WARN_ON(!atomic_read(&sd->s_count)); + atomic_inc(&sd->s_count); + } + return sd; +} +#define sysfs_get(sd) __sysfs_get(sd) + +static inline void __sysfs_put(struct sysfs_dirent *sd) +{ + if (sd && atomic_dec_and_test(&sd->s_count)) + release_sysfs_dirent(sd); +} +#define sysfs_put(sd) __sysfs_put(sd) + +/* + * inode.c + */ +struct inode *sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd); +void sysfs_evict_inode(struct inode *inode); +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr); +int sysfs_permission(struct inode *inode, int mask); +int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); +int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat); +int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags); +int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const char *name); +int sysfs_inode_init(void); + +/* + * file.c + */ +extern const struct file_operations sysfs_file_operations; + +int sysfs_add_file(struct sysfs_dirent *dir_sd, + const struct attribute *attr, int type); + +int sysfs_add_file_mode(struct sysfs_dirent *dir_sd, + const struct attribute *attr, int type, umode_t amode); +/* + * bin.c + */ +extern const struct file_operations bin_fops; +void unmap_bin_file(struct sysfs_dirent *attr_sd); + +/* + * symlink.c + */ +extern const struct inode_operations sysfs_symlink_inode_operations; 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