diff options
Diffstat (limited to 'fs/sysfs/file.c')
-rw-r--r-- | fs/sysfs/file.c | 344 |
1 files changed, 278 insertions, 66 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 130fc6fbcc03..a12ac0356c69 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -6,7 +6,7 @@ * Copyright (c) 2007 SUSE Linux Products GmbH * Copyright (c) 2007 Tejun Heo <teheo@suse.de> * - * Please see Documentation/filesystems/sysfs.txt for more information. + * Please see Documentation/filesystems/sysfs.rst for more information. */ #include <linux/module.h> @@ -15,6 +15,7 @@ #include <linux/list.h> #include <linux/mutex.h> #include <linux/seq_file.h> +#include <linux/mm.h> #include "sysfs.h" @@ -44,6 +45,9 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v) ssize_t count; char *buf; + if (WARN_ON_ONCE(!ops->show)) + return -EINVAL; + /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */ count = seq_get_buf(sf, &buf); if (count < PAGE_SIZE) { @@ -52,15 +56,9 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v) } memset(buf, 0, PAGE_SIZE); - /* - * 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->kn->priv, buf); - if (count < 0) - return count; - } + count = ops->show(kobj, of->kn->priv, buf); + if (count < 0) + return count; /* * The code works fine with PAGE_SIZE return but it's likely to @@ -169,6 +167,16 @@ static int sysfs_kf_bin_mmap(struct kernfs_open_file *of, return battr->mmap(of->file, kobj, battr, vma); } +static int sysfs_kf_bin_open(struct kernfs_open_file *of) +{ + struct bin_attribute *battr = of->kn->priv; + + if (battr->f_mapping) + of->file->f_mapping = battr->f_mapping(); + + return 0; +} + void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr) { struct kernfs_node *kn = kobj->sd, *tmp; @@ -240,70 +248,86 @@ static const struct kernfs_ops sysfs_bin_kfops_mmap = { .read = sysfs_kf_bin_read, .write = sysfs_kf_bin_write, .mmap = sysfs_kf_bin_mmap, + .open = sysfs_kf_bin_open, }; int sysfs_add_file_mode_ns(struct kernfs_node *parent, - const struct attribute *attr, bool is_bin, - umode_t mode, kuid_t uid, kgid_t gid, const void *ns) + const struct attribute *attr, umode_t mode, kuid_t uid, + kgid_t gid, const void *ns) { + struct kobject *kobj = parent->priv; + const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops; struct lock_class_key *key = NULL; - const struct kernfs_ops *ops; + const struct kernfs_ops *ops = NULL; struct kernfs_node *kn; - loff_t size; - - if (!is_bin) { - struct kobject *kobj = parent->priv; - const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops; - - /* every kobject with an attribute needs a ktype assigned */ - if (WARN(!sysfs_ops, KERN_ERR - "missing sysfs attribute operations for kobject: %s\n", - kobject_name(kobj))) - return -EINVAL; - - if (sysfs_ops->show && sysfs_ops->store) { - if (mode & SYSFS_PREALLOC) - ops = &sysfs_prealloc_kfops_rw; - else - ops = &sysfs_file_kfops_rw; - } else if (sysfs_ops->show) { - if (mode & SYSFS_PREALLOC) - ops = &sysfs_prealloc_kfops_ro; - else - ops = &sysfs_file_kfops_ro; - } else if (sysfs_ops->store) { - if (mode & SYSFS_PREALLOC) - ops = &sysfs_prealloc_kfops_wo; - else - ops = &sysfs_file_kfops_wo; - } else - ops = &sysfs_file_kfops_empty; - - size = PAGE_SIZE; + + /* every kobject with an attribute needs a ktype assigned */ + if (WARN(!sysfs_ops, KERN_ERR + "missing sysfs attribute operations for kobject: %s\n", + kobject_name(kobj))) + return -EINVAL; + + if (mode & SYSFS_PREALLOC) { + if (sysfs_ops->show && sysfs_ops->store) + ops = &sysfs_prealloc_kfops_rw; + else if (sysfs_ops->show) + ops = &sysfs_prealloc_kfops_ro; + else if (sysfs_ops->store) + ops = &sysfs_prealloc_kfops_wo; } else { - struct bin_attribute *battr = (void *)attr; - - if (battr->mmap) - ops = &sysfs_bin_kfops_mmap; - else if (battr->read && battr->write) - ops = &sysfs_bin_kfops_rw; - else if (battr->read) - ops = &sysfs_bin_kfops_ro; - else if (battr->write) - ops = &sysfs_bin_kfops_wo; - else - ops = &sysfs_file_kfops_empty; - - size = battr->size; + if (sysfs_ops->show && sysfs_ops->store) + ops = &sysfs_file_kfops_rw; + else if (sysfs_ops->show) + ops = &sysfs_file_kfops_ro; + else if (sysfs_ops->store) + ops = &sysfs_file_kfops_wo; } + if (!ops) + ops = &sysfs_file_kfops_empty; + #ifdef CONFIG_DEBUG_LOCK_ALLOC if (!attr->ignore_lockdep) key = attr->key ?: (struct lock_class_key *)&attr->skey; #endif kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid, - size, ops, (void *)attr, ns, key); + PAGE_SIZE, ops, (void *)attr, ns, key); + if (IS_ERR(kn)) { + if (PTR_ERR(kn) == -EEXIST) + sysfs_warn_dup(parent, attr->name); + return PTR_ERR(kn); + } + return 0; +} + +int sysfs_add_bin_file_mode_ns(struct kernfs_node *parent, + const struct bin_attribute *battr, umode_t mode, + kuid_t uid, kgid_t gid, const void *ns) +{ + const struct attribute *attr = &battr->attr; + struct lock_class_key *key = NULL; + const struct kernfs_ops *ops; + struct kernfs_node *kn; + + if (battr->mmap) + ops = &sysfs_bin_kfops_mmap; + else if (battr->read && battr->write) + ops = &sysfs_bin_kfops_rw; + else if (battr->read) + ops = &sysfs_bin_kfops_ro; + else if (battr->write) + ops = &sysfs_bin_kfops_wo; + else + ops = &sysfs_file_kfops_empty; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + if (!attr->ignore_lockdep) + key = attr->key ?: (struct lock_class_key *)&attr->skey; +#endif + + kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid, + battr->size, ops, (void *)attr, ns, key); if (IS_ERR(kn)) { if (PTR_ERR(kn) == -EEXIST) sysfs_warn_dup(parent, attr->name); @@ -328,9 +352,7 @@ int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, return -EINVAL; kobject_get_ownership(kobj, &uid, &gid); - return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, - uid, gid, ns); - + return sysfs_add_file_mode_ns(kobj->sd, attr, attr->mode, uid, gid, ns); } EXPORT_SYMBOL_GPL(sysfs_create_file_ns); @@ -373,8 +395,8 @@ int sysfs_add_file_to_group(struct kobject *kobj, return -ENOENT; kobject_get_ownership(kobj, &uid, &gid); - error = sysfs_add_file_mode_ns(parent, attr, false, - attr->mode, uid, gid, NULL); + error = sysfs_add_file_mode_ns(parent, attr, attr->mode, uid, gid, + NULL); kernfs_put(parent); return error; @@ -492,6 +514,7 @@ bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr) kernfs_put(kn); return ret; } +EXPORT_SYMBOL_GPL(sysfs_remove_file_self); void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr) { @@ -542,8 +565,8 @@ int sysfs_create_bin_file(struct kobject *kobj, return -EINVAL; kobject_get_ownership(kobj, &uid, &gid); - return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true, - attr->attr.mode, uid, gid, NULL); + return sysfs_add_bin_file_mode_ns(kobj->sd, attr, attr->attr.mode, uid, + gid, NULL); } EXPORT_SYMBOL_GPL(sysfs_create_bin_file); @@ -558,3 +581,192 @@ void sysfs_remove_bin_file(struct kobject *kobj, kernfs_remove_by_name(kobj->sd, attr->attr.name); } EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); + +static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid, + kgid_t kgid) +{ + struct iattr newattrs = { + .ia_valid = ATTR_UID | ATTR_GID, + .ia_uid = kuid, + .ia_gid = kgid, + }; + return kernfs_setattr(kn, &newattrs); +} + +/** + * sysfs_link_change_owner - change owner of a sysfs file. + * @kobj: object of the kernfs_node the symlink is located in. + * @targ: object of the kernfs_node the symlink points to. + * @name: name of the link. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This function looks up the sysfs symlink entry @name under @kobj and changes + * the ownership to @kuid/@kgid. The symlink is looked up in the namespace of + * @targ. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, + const char *name, kuid_t kuid, kgid_t kgid) +{ + struct kernfs_node *kn = NULL; + int error; + + if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs) + return -EINVAL; + + error = -ENOENT; + kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns); + if (!kn) + goto out; + + error = -EINVAL; + if (kernfs_type(kn) != KERNFS_LINK) + goto out; + if (kn->symlink.target_kn->priv != targ) + goto out; + + error = internal_change_owner(kn, kuid, kgid); + +out: + kernfs_put(kn); + return error; +} + +/** + * sysfs_file_change_owner - change owner of a sysfs file. + * @kobj: object. + * @name: name of the file to change. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This function looks up the sysfs entry @name under @kobj and changes the + * ownership to @kuid/@kgid. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, + kgid_t kgid) +{ + struct kernfs_node *kn; + int error; + + if (!name) + return -EINVAL; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + kn = kernfs_find_and_get(kobj->sd, name); + if (!kn) + return -ENOENT; + + error = internal_change_owner(kn, kuid, kgid); + + kernfs_put(kn); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_file_change_owner); + +/** + * sysfs_change_owner - change owner of the given object. + * @kobj: object. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * Change the owner of the default directory, files, groups, and attributes of + * @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs + * entries for a kobject are added by driver core. In summary, + * sysfs_change_owner() takes care of the default directory entry for @kobj, + * the default attributes associated with the ktype of @kobj and the default + * attributes associated with the ktype of @kobj. + * Additional properties not added by driver core have to be changed by the + * driver or subsystem which created them. This is similar to how + * driver/subsystem specific entries are removed. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid) +{ + int error; + const struct kobj_type *ktype; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + /* Change the owner of the kobject itself. */ + error = internal_change_owner(kobj->sd, kuid, kgid); + if (error) + return error; + + ktype = get_ktype(kobj); + if (ktype) { + /* + * Change owner of the default groups associated with the + * ktype of @kobj. + */ + error = sysfs_groups_change_owner(kobj, ktype->default_groups, + kuid, kgid); + if (error) + return error; + } + + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_change_owner); + +/** + * sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer. + * @buf: start of PAGE_SIZE buffer. + * @fmt: format + * @...: optional arguments to @format + * + * + * Returns number of characters written to @buf. + */ +int sysfs_emit(char *buf, const char *fmt, ...) +{ + va_list args; + int len; + + if (WARN(!buf || offset_in_page(buf), + "invalid sysfs_emit: buf:%p\n", buf)) + return 0; + + va_start(args, fmt); + len = vscnprintf(buf, PAGE_SIZE, fmt, args); + va_end(args); + + return len; +} +EXPORT_SYMBOL_GPL(sysfs_emit); + +/** + * sysfs_emit_at - scnprintf equivalent, aware of PAGE_SIZE buffer. + * @buf: start of PAGE_SIZE buffer. + * @at: offset in @buf to start write in bytes + * @at must be >= 0 && < PAGE_SIZE + * @fmt: format + * @...: optional arguments to @fmt + * + * + * Returns number of characters written starting at &@buf[@at]. + */ +int sysfs_emit_at(char *buf, int at, const char *fmt, ...) +{ + va_list args; + int len; + + if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE, + "invalid sysfs_emit_at: buf:%p at:%d\n", buf, at)) + return 0; + + va_start(args, fmt); + len = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args); + va_end(args); + + return len; +} +EXPORT_SYMBOL_GPL(sysfs_emit_at); |