| /* |
| * 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 <linux/uaccess.h> |
| #include <linux/seq_file.h> |
| #include <linux/mm.h> |
| |
| #include "sysfs.h" |
| |
| /* |
| * There's one sysfs_open_file for each open file and one sysfs_open_dirent |
| * for each sysfs_dirent with one or more open files. |
| * |
| * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is |
| * protected by sysfs_open_dirent_lock. |
| * |
| * filp->private_data points to seq_file whose ->private points to |
| * sysfs_open_file. sysfs_open_files are chained at |
| * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex. |
| */ |
| static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
| static DEFINE_MUTEX(sysfs_open_file_mutex); |
| |
| struct sysfs_open_dirent { |
| atomic_t refcnt; |
| atomic_t event; |
| wait_queue_head_t poll; |
| struct list_head files; /* goes through sysfs_open_file.list */ |
| }; |
| |
| struct sysfs_open_file { |
| struct sysfs_dirent *sd; |
| struct file *file; |
| struct mutex mutex; |
| int event; |
| struct list_head list; |
| |
| bool mmapped; |
| const struct vm_operations_struct *vm_ops; |
| }; |
| |
| static bool sysfs_is_bin(struct sysfs_dirent *sd) |
| { |
| return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR; |
| } |
| |
| static struct sysfs_open_file *sysfs_of(struct file *file) |
| { |
| return ((struct seq_file *)file->private_data)->private; |
| } |
| |
| /* |
| * Determine ktype->sysfs_ops for the given sysfs_dirent. This function |
| * must be called while holding an active reference. |
| */ |
| static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) |
| { |
| struct kobject *kobj = sd->s_parent->priv; |
| |
| if (!sysfs_ignore_lockdep(sd)) |
| lockdep_assert_held(sd); |
| return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; |
| } |
| |
| /* |
| * Reads on sysfs are handled through seq_file, which takes care of hairy |
| * details like buffering and seeking. The following function pipes |
| * sysfs_ops->show() result through seq_file. |
| */ |
| static int sysfs_kf_seq_show(struct seq_file *sf, void *v) |
| { |
| struct sysfs_open_file *of = sf->private; |
| struct kobject *kobj = of->sd->s_parent->priv; |
| const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
| ssize_t count; |
| char *buf; |
| |
| /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
| count = seq_get_buf(sf, &buf); |
| if (count < PAGE_SIZE) { |
| seq_commit(sf, -1); |
| return 0; |
| } |
| |
| /* |
| * Invoke show(). Control may reach here via seq file lseek even |
| * if @ops->show() isn't implemented. |
| */ |
| if (ops->show) { |
| count = ops->show(kobj, of->sd->priv, buf); |
| if (count < 0) |
| return count; |
| } |
| |
| /* |
| * 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; |
| } |
| seq_commit(sf, count); |
| return 0; |
| } |
| |
| static ssize_t sysfs_kf_bin_read(struct sysfs_open_file *of, char *buf, |
| size_t count, loff_t pos) |
| { |
| struct bin_attribute *battr = of->sd->priv; |
| struct kobject *kobj = of->sd->s_parent->priv; |
| loff_t size = file_inode(of->file)->i_size; |
| |
| if (!count) |
| return 0; |
| |
| if (size) { |
| if (pos > size) |
| return 0; |
| if (pos + count > size) |
| count = size - pos; |
| } |
| |
| if (!battr->read) |
| return -EIO; |
| |
| return battr->read(of->file, kobj, battr, buf, pos, count); |
| } |
| |
| static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) |
| { |
| struct sysfs_open_file *of = sf->private; |
| |
| /* |
| * @of->mutex nests outside active ref and is just to ensure that |
| * the ops aren't called concurrently for the same open file. |
| */ |
| mutex_lock(&of->mutex); |
| if (!sysfs_get_active(of->sd)) |
| return ERR_PTR(-ENODEV); |
| |
| /* |
| * The same behavior and code as single_open(). Returns !NULL if |
| * pos is at the beginning; otherwise, NULL. |
| */ |
| return NULL + !*ppos; |
| } |
| |
| static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) |
| { |
| /* |
| * The same behavior and code as single_open(), always terminate |
| * after the initial read. |
| */ |
| ++*ppos; |
| return NULL; |
| } |
| |
| static void kernfs_seq_stop(struct seq_file *sf, void *v) |
| { |
| struct sysfs_open_file *of = sf->private; |
| |
| sysfs_put_active(of->sd); |
| mutex_unlock(&of->mutex); |
| } |
| |
| static int kernfs_seq_show(struct seq_file *sf, void *v) |
| { |
| struct sysfs_open_file *of = sf->private; |
| |
| of->event = atomic_read(&of->sd->s_attr.open->event); |
| |
| return sysfs_kf_seq_show(sf, v); |
| } |
| |
| static const struct seq_operations kernfs_seq_ops = { |
| .start = kernfs_seq_start, |
| .next = kernfs_seq_next, |
| .stop = kernfs_seq_stop, |
| .show = kernfs_seq_show, |
| }; |
| |
| /* |
| * As reading a bin file can have side-effects, the exact offset and bytes |
| * specified in read(2) call should be passed to the read callback making |
| * it difficult to use seq_file. Implement simplistic custom buffering for |
| * bin files. |
| */ |
| static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, |
| char __user *user_buf, size_t count, |
| loff_t *ppos) |
| { |
| ssize_t len = min_t(size_t, count, PAGE_SIZE); |
| char *buf; |
| |
| buf = kmalloc(len, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| /* |
| * @of->mutex nests outside active ref and is just to ensure that |
| * the ops aren't called concurrently for the same open file. |
| */ |
| mutex_lock(&of->mutex); |
| if (!sysfs_get_active(of->sd)) { |
| len = -ENODEV; |
| mutex_unlock(&of->mutex); |
| goto out_free; |
| } |
| |
| len = sysfs_kf_bin_read(of, buf, len, *ppos); |
| |
| sysfs_put_active(of->sd); |
| mutex_unlock(&of->mutex); |
| |
| if (len < 0) |
| goto out_free; |
| |
| if (copy_to_user(user_buf, buf, len)) { |
| len = -EFAULT; |
| goto out_free; |
| } |
| |
| *ppos += len; |
| |
| out_free: |
| kfree(buf); |
| return len; |
| } |
| |
| /** |
| * kernfs_file_read - kernfs vfs read callback |
| * @file: file pointer |
| * @user_buf: data to write |
| * @count: number of bytes |
| * @ppos: starting offset |
| */ |
| static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct sysfs_open_file *of = sysfs_of(file); |
| |
| if (sysfs_is_bin(of->sd)) |
| return kernfs_file_direct_read(of, user_buf, count, ppos); |
| else |
| return seq_read(file, user_buf, count, ppos); |
| } |
| |
| /* kernfs write callback for regular sysfs files */ |
| static ssize_t sysfs_kf_write(struct sysfs_open_file *of, char *buf, |
| size_t count, loff_t pos) |
| { |
| const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
| struct kobject *kobj = of->sd->s_parent->priv; |
| |
| if (!count) |
| return 0; |
| |
| return ops->store(kobj, of->sd->priv, buf, count); |
| } |
| |
| /* kernfs write callback for bin sysfs files */ |
| static ssize_t sysfs_kf_bin_write(struct sysfs_open_file *of, char *buf, |
| size_t count, loff_t pos) |
| { |
| struct bin_attribute *battr = of->sd->priv; |
| struct kobject *kobj = of->sd->s_parent->priv; |
| loff_t size = file_inode(of->file)->i_size; |
| |
| if (size) { |
| if (size <= pos) |
| return 0; |
| count = min_t(ssize_t, count, size - pos); |
| } |
| if (!count) |
| return 0; |
| |
| if (!battr->write) |
| return -EIO; |
| |
| return battr->write(of->file, kobj, battr, buf, pos, count); |
| } |
| |
| /** |
| * kernfs_file_write - kernfs vfs write callback |
| * @file: file pointer |
| * @user_buf: data to write |
| * @count: number of bytes |
| * @ppos: starting offset |
| * |
| * Copy data in from userland and pass it to the matching kernfs write |
| * operation. |
| * |
| * 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 kernfs_file_write(struct file *file, const char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct sysfs_open_file *of = sysfs_of(file); |
| ssize_t len = min_t(size_t, count, PAGE_SIZE); |
| char *buf; |
| |
| buf = kmalloc(len + 1, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| if (copy_from_user(buf, user_buf, len)) { |
| len = -EFAULT; |
| goto out_free; |
| } |
| buf[len] = '\0'; /* guarantee string termination */ |
| |
| /* |
| * @of->mutex nests outside active ref and is just to ensure that |
| * the ops aren't called concurrently for the same open file. |
| */ |
| mutex_lock(&of->mutex); |
| if (!sysfs_get_active(of->sd)) { |
| mutex_unlock(&of->mutex); |
| len = -ENODEV; |
| goto out_free; |
| } |
| |
| if (sysfs_is_bin(of->sd)) |
| len = sysfs_kf_bin_write(of, buf, len, *ppos); |
| else |
| len = sysfs_kf_write(of, buf, len, *ppos); |
| |
| sysfs_put_active(of->sd); |
| mutex_unlock(&of->mutex); |
| |
| if (len > 0) |
| *ppos += len; |
| out_free: |
| kfree(buf); |
| return len; |
| } |
| |
| static void sysfs_bin_vma_open(struct vm_area_struct *vma) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| |
| if (!of->vm_ops) |
| return; |
| |
| if (!sysfs_get_active(of->sd)) |
| return; |
| |
| if (of->vm_ops->open) |
| of->vm_ops->open(vma); |
| |
| sysfs_put_active(of->sd); |
| } |
| |
| static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| int ret; |
| |
| if (!of->vm_ops) |
| return VM_FAULT_SIGBUS; |
| |
| if (!sysfs_get_active(of->sd)) |
| return VM_FAULT_SIGBUS; |
| |
| ret = VM_FAULT_SIGBUS; |
| if (of->vm_ops->fault) |
| ret = of->vm_ops->fault(vma, vmf); |
| |
| sysfs_put_active(of->sd); |
| return ret; |
| } |
| |
| static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma, |
| struct vm_fault *vmf) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| int ret; |
| |
| if (!of->vm_ops) |
| return VM_FAULT_SIGBUS; |
| |
| if (!sysfs_get_active(of->sd)) |
| return VM_FAULT_SIGBUS; |
| |
| ret = 0; |
| if (of->vm_ops->page_mkwrite) |
| ret = of->vm_ops->page_mkwrite(vma, vmf); |
| else |
| file_update_time(file); |
| |
| sysfs_put_active(of->sd); |
| return ret; |
| } |
| |
| static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr, |
| void *buf, int len, int write) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| int ret; |
| |
| if (!of->vm_ops) |
| return -EINVAL; |
| |
| if (!sysfs_get_active(of->sd)) |
| return -EINVAL; |
| |
| ret = -EINVAL; |
| if (of->vm_ops->access) |
| ret = of->vm_ops->access(vma, addr, buf, len, write); |
| |
| sysfs_put_active(of->sd); |
| return ret; |
| } |
| |
| #ifdef CONFIG_NUMA |
| static int sysfs_bin_set_policy(struct vm_area_struct *vma, |
| struct mempolicy *new) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| int ret; |
| |
| if (!of->vm_ops) |
| return 0; |
| |
| if (!sysfs_get_active(of->sd)) |
| return -EINVAL; |
| |
| ret = 0; |
| if (of->vm_ops->set_policy) |
| ret = of->vm_ops->set_policy(vma, new); |
| |
| sysfs_put_active(of->sd); |
| return ret; |
| } |
| |
| static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma, |
| unsigned long addr) |
| { |
| struct file *file = vma->vm_file; |
| struct sysfs_open_file *of = sysfs_of(file); |
| struct mempolicy *pol; |
| |
| if (!of->vm_ops) |
| return vma->vm_policy; |
| |
| if (!sysfs_get_active(of->sd)) |
| return vma->vm_policy; |
| |
| pol = vma->vm_policy; |
| if (of->vm_ops->get_policy) |
| pol = of->vm_ops->get_policy(vma, addr); |
| |
| sysfs_put_active(of->sd); |
| return pol; |
| } |
| |
| static int sysfs_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 sysfs_open_file *of = sysfs_of(file); |
| int ret; |
| |
| if (!of->vm_ops) |
| return 0; |
| |
| if (!sysfs_get_active(of->sd)) |
| return 0; |
| |
| ret = 0; |
| if (of->vm_ops->migrate) |
| ret = of->vm_ops->migrate(vma, from, to, flags); |
| |
| sysfs_put_active(of->sd); |
| return ret; |
| } |
| #endif |
| |
| static const struct vm_operations_struct sysfs_bin_vm_ops = { |
| .open = sysfs_bin_vma_open, |
| .fault = sysfs_bin_fault, |
| .page_mkwrite = sysfs_bin_page_mkwrite, |
| .access = sysfs_bin_access, |
| #ifdef CONFIG_NUMA |
| .set_policy = sysfs_bin_set_policy, |
| .get_policy = sysfs_bin_get_policy, |
| .migrate = sysfs_bin_migrate, |
| #endif |
| }; |
| |
| static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| struct sysfs_open_file *of = sysfs_of(file); |
| struct bin_attribute *battr = of->sd->priv; |
| struct kobject *kobj = of->sd->s_parent->priv; |
| int rc; |
| |
| mutex_lock(&of->mutex); |
| |
| /* need of->sd for battr, its parent for kobj */ |
| rc = -ENODEV; |
| if (!sysfs_get_active(of->sd)) |
| goto out_unlock; |
| |
| if (!battr->mmap) |
| goto out_put; |
| |
| rc = battr->mmap(file, kobj, battr, 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 (of->mmapped && of->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; |
| of->mmapped = 1; |
| of->vm_ops = vma->vm_ops; |
| vma->vm_ops = &sysfs_bin_vm_ops; |
| out_put: |
| sysfs_put_active(of->sd); |
| out_unlock: |
| mutex_unlock(&of->mutex); |
| |
| return rc; |
| } |
| |
| /** |
| * sysfs_get_open_dirent - get or create sysfs_open_dirent |
| * @sd: target sysfs_dirent |
| * @of: sysfs_open_file for this instance of open |
| * |
| * If @sd->s_attr.open exists, increment its reference count; |
| * otherwise, create one. @of is chained to the files 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_open_file *of) |
| { |
| struct sysfs_open_dirent *od, *new_od = NULL; |
| |
| retry: |
| mutex_lock(&sysfs_open_file_mutex); |
| 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(&of->list, &od->files); |
| } |
| |
| spin_unlock_irq(&sysfs_open_dirent_lock); |
| mutex_unlock(&sysfs_open_file_mutex); |
| |
| 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->files); |
| goto retry; |
| } |
| |
| /** |
| * sysfs_put_open_dirent - put sysfs_open_dirent |
| * @sd: target sysfs_dirent |
| * @of: associated sysfs_open_file |
| * |
| * Put @sd->s_attr.open and unlink @of from the files list. If |
| * reference count reaches zero, disassociate and free it. |
| * |
| * LOCKING: |
| * None. |
| */ |
| static void sysfs_put_open_dirent(struct sysfs_dirent *sd, |
| struct sysfs_open_file *of) |
| { |
| struct sysfs_open_dirent *od = sd->s_attr.open; |
| unsigned long flags; |
| |
| mutex_lock(&sysfs_open_file_mutex); |
| spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
| |
| if (of) |
| list_del(&of->list); |
| |
| if (atomic_dec_and_test(&od->refcnt)) |
| sd->s_attr.open = NULL; |
| else |
| od = NULL; |
| |
| spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
| mutex_unlock(&sysfs_open_file_mutex); |
| |
| 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->priv; |
| struct sysfs_open_file *of; |
| bool has_read, has_write, has_mmap; |
| int error = -EACCES; |
| |
| /* need attr_sd for attr and ops, its parent for kobj */ |
| if (!sysfs_get_active(attr_sd)) |
| return -ENODEV; |
| |
| if (sysfs_is_bin(attr_sd)) { |
| struct bin_attribute *battr = attr_sd->priv; |
| |
| has_read = battr->read || battr->mmap; |
| has_write = battr->write || battr->mmap; |
| has_mmap = battr->mmap; |
| } else { |
| const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); |
| |
| /* every kobject with an attribute needs a ktype assigned */ |
| if (WARN(!ops, KERN_ERR |
| "missing sysfs attribute operations for kobject: %s\n", |
| kobject_name(kobj))) |
| goto err_out; |
| |
| has_read = ops->show; |
| has_write = ops->store; |
| has_mmap = false; |
| } |
| |
| /* check perms and supported operations */ |
| if ((file->f_mode & FMODE_WRITE) && |
| (!(inode->i_mode & S_IWUGO) || !has_write)) |
| goto err_out; |
| |
| if ((file->f_mode & FMODE_READ) && |
| (!(inode->i_mode & S_IRUGO) || !has_read)) |
| goto err_out; |
| |
| /* allocate a sysfs_open_file for the file */ |
| error = -ENOMEM; |
| of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
| if (!of) |
| goto err_out; |
| |
| /* |
| * The following is done to give a different lockdep key to |
| * @of->mutex for files which implement mmap. This is a rather |
| * crude way to avoid false positive lockdep warning around |
| * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and |
| * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under |
| * which mm->mmap_sem nests, while holding @of->mutex. As each |
| * open file has a separate mutex, it's okay as long as those don't |
| * happen on the same file. At this point, we can't easily give |
| * each file a separate locking class. Let's differentiate on |
| * whether the file has mmap or not for now. |
| */ |
| if (has_mmap) |
| mutex_init(&of->mutex); |
| else |
| mutex_init(&of->mutex); |
| |
| of->sd = attr_sd; |
| of->file = file; |
| |
| /* |
| * Always instantiate seq_file even if read access doesn't use |
| * seq_file or is not requested. This unifies private data access |
| * and readable regular files are the vast majority anyway. |
| */ |
| if (sysfs_is_bin(attr_sd)) |
| error = seq_open(file, NULL); |
| else |
| error = seq_open(file, &kernfs_seq_ops); |
| if (error) |
| goto err_free; |
| |
| ((struct seq_file *)file->private_data)->private = of; |
| |
| /* seq_file clears PWRITE unconditionally, restore it if WRITE */ |
| if (file->f_mode & FMODE_WRITE) |
| file->f_mode |= FMODE_PWRITE; |
| |
| /* make sure we have open dirent struct */ |
| error = sysfs_get_open_dirent(attr_sd, of); |
| if (error) |
| goto err_close; |
| |
| /* open succeeded, put active references */ |
| sysfs_put_active(attr_sd); |
| return 0; |
| |
| err_close: |
| seq_release(inode, file); |
| err_free: |
| kfree(of); |
| 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_open_file *of = sysfs_of(filp); |
| |
| sysfs_put_open_dirent(sd, of); |
| seq_release(inode, filp); |
| kfree(of); |
| |
| return 0; |
| } |
| |
| void sysfs_unmap_bin_file(struct sysfs_dirent *sd) |
| { |
| struct sysfs_open_dirent *od; |
| struct sysfs_open_file *of; |
| |
| if (!sysfs_is_bin(sd)) |
| return; |
| |
| spin_lock_irq(&sysfs_open_dirent_lock); |
| od = sd->s_attr.open; |
| if (od) |
| atomic_inc(&od->refcnt); |
| spin_unlock_irq(&sysfs_open_dirent_lock); |
| if (!od) |
| return; |
| |
| mutex_lock(&sysfs_open_file_mutex); |
| list_for_each_entry(of, &od->files, list) { |
| struct inode *inode = file_inode(of->file); |
| unmap_mapping_range(inode->i_mapping, 0, 0, 1); |
| } |
| mutex_unlock(&sysfs_open_file_mutex); |
| |
| sysfs_put_open_dirent(sd, NULL); |
| } |
| |
| /* 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_open_file *of = sysfs_of(filp); |
| 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 (of->event != atomic_read(&od->event)) |
| goto trigger; |
| |
| return DEFAULT_POLLMASK; |
| |
| trigger: |
| 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); |
| |
| if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
| 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, dir, NULL); |
| if (sd && attr) |
| sd = sysfs_find_dirent(sd, attr, NULL); |
| if (sd) |
| sysfs_notify_dirent(sd); |
| |
| mutex_unlock(&sysfs_mutex); |
| } |
| EXPORT_SYMBOL_GPL(sysfs_notify); |
| |
| const struct file_operations sysfs_file_operations = { |
| .read = kernfs_file_read, |
| .write = kernfs_file_write, |
| .llseek = generic_file_llseek, |
| .open = sysfs_open_file, |
| .release = sysfs_release, |
| .poll = sysfs_poll, |
| }; |
| |
| const struct file_operations sysfs_bin_operations = { |
| .read = kernfs_file_read, |
| .write = kernfs_file_write, |
| .llseek = generic_file_llseek, |
| .mmap = sysfs_bin_mmap, |
| .open = sysfs_open_file, |
| .release = sysfs_release, |
| .poll = sysfs_poll, |
| }; |
| |
| int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
| const struct attribute *attr, int type, |
| umode_t amode, const void *ns) |
| { |
| umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
| struct sysfs_addrm_cxt acxt; |
| struct sysfs_dirent *sd; |
| int rc; |
| |
| sd = sysfs_new_dirent(attr->name, mode, type); |
| if (!sd) |
| return -ENOMEM; |
| |
| sd->s_ns = ns; |
| sd->priv = (void *)attr; |
| sysfs_dirent_init_lockdep(sd); |
| |
| sysfs_addrm_start(&acxt); |
| rc = sysfs_add_one(&acxt, sd, dir_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_ns(dir_sd, attr, type, attr->mode, NULL); |
| } |
| |
| /** |
| * sysfs_create_file_ns - create an attribute file for an object with custom ns |
| * @kobj: object we're creating for |
| * @attr: attribute descriptor |
| * @ns: namespace the new file should belong to |
| */ |
| int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
| const void *ns) |
| { |
| BUG_ON(!kobj || !kobj->sd || !attr); |
| |
| return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
| attr->mode, ns); |
| |
| } |
| EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
| |
| 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; |
| } |
| EXPORT_SYMBOL_GPL(sysfs_create_files); |
| |
| /** |
| * 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, 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; |
| int rc; |
| |
| sd = sysfs_get_dirent(kobj->sd, attr->name); |
| if (!sd) |
| return -ENOENT; |
| |
| newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
| newattrs.ia_valid = ATTR_MODE; |
| |
| rc = kernfs_setattr(sd, &newattrs); |
| |
| sysfs_put(sd); |
| return rc; |
| } |
| EXPORT_SYMBOL_GPL(sysfs_chmod_file); |
| |
| /** |
| * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
| * @kobj: object we're acting for |
| * @attr: attribute descriptor |
| * @ns: namespace tag of the file to remove |
| * |
| * Hash the attribute name and namespace tag and kill the victim. |
| */ |
| void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
| const void *ns) |
| { |
| struct sysfs_dirent *dir_sd = kobj->sd; |
| |
| kernfs_remove_by_name_ns(dir_sd, attr->name, ns); |
| } |
| EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
| |
| 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]); |
| } |
| EXPORT_SYMBOL_GPL(sysfs_remove_files); |
| |
| /** |
| * 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, group); |
| else |
| dir_sd = sysfs_get(kobj->sd); |
| if (dir_sd) { |
| kernfs_remove_by_name(dir_sd, attr->name); |
| sysfs_put(dir_sd); |
| } |
| } |
| EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); |
| |
| /** |
| * 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); |
| } |
| EXPORT_SYMBOL_GPL(sysfs_create_bin_file); |
| |
| /** |
| * 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) |
| { |
| kernfs_remove_by_name(kobj->sd, attr->attr.name); |
| } |
| EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); |
| |
| 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); |