diff options
Diffstat (limited to 'fs/proc/generic.c')
| -rw-r--r-- | fs/proc/generic.c | 645 |
1 files changed, 645 insertions, 0 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c new file mode 100644 index 000000000..e5dee5c31 --- /dev/null +++ b/fs/proc/generic.c @@ -0,0 +1,645 @@ +/* + * proc/fs/generic.c --- generic routines for the proc-fs + * + * This file contains generic proc-fs routines for handling + * directories and files. + * + * Copyright (C) 1991, 1992 Linus Torvalds. + * Copyright (C) 1997 Theodore Ts'o + */ + +#include <linux/errno.h> +#include <linux/time.h> +#include <linux/proc_fs.h> +#include <linux/stat.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/printk.h> +#include <linux/mount.h> +#include <linux/init.h> +#include <linux/idr.h> +#include <linux/bitops.h> +#include <linux/spinlock.h> +#include <linux/completion.h> +#include <asm/uaccess.h> + +#include "internal.h" + +static DEFINE_SPINLOCK(proc_subdir_lock); + +static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de) +{ + if (len < de->namelen) + return -1; + if (len > de->namelen) + return 1; + + return memcmp(name, de->name, len); +} + +static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir) +{ + return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry, + subdir_node); +} + +static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir) +{ + return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry, + subdir_node); +} + +static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir, + const char *name, + unsigned int len) +{ + struct rb_node *node = dir->subdir.rb_node; + + while (node) { + struct proc_dir_entry *de = container_of(node, + struct proc_dir_entry, + subdir_node); + int result = proc_match(len, name, de); + + if (result < 0) + node = node->rb_left; + else if (result > 0) + node = node->rb_right; + else + return de; + } + return NULL; +} + +static bool pde_subdir_insert(struct proc_dir_entry *dir, + struct proc_dir_entry *de) +{ + struct rb_root *root = &dir->subdir; + struct rb_node **new = &root->rb_node, *parent = NULL; + + /* Figure out where to put new node */ + while (*new) { + struct proc_dir_entry *this = + container_of(*new, struct proc_dir_entry, subdir_node); + int result = proc_match(de->namelen, de->name, this); + + parent = *new; + if (result < 0) + new = &(*new)->rb_left; + else if (result > 0) + new = &(*new)->rb_right; + else + return false; + } + + /* Add new node and rebalance tree. */ + rb_link_node(&de->subdir_node, parent, new); + rb_insert_color(&de->subdir_node, root); + return true; +} + +static int proc_notify_change(struct dentry *dentry, struct iattr *iattr) +{ + struct inode *inode = d_inode(dentry); + struct proc_dir_entry *de = PDE(inode); + int error; + + error = inode_change_ok(inode, iattr); + if (error) + return error; + + setattr_copy(inode, iattr); + mark_inode_dirty(inode); + + proc_set_user(de, inode->i_uid, inode->i_gid); + de->mode = inode->i_mode; + return 0; +} + +static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry, + struct kstat *stat) +{ + struct inode *inode = d_inode(dentry); + struct proc_dir_entry *de = PDE(inode); + if (de && de->nlink) + set_nlink(inode, de->nlink); + + generic_fillattr(inode, stat); + return 0; +} + +static const struct inode_operations proc_file_inode_operations = { + .setattr = proc_notify_change, +}; + +/* + * This function parses a name such as "tty/driver/serial", and + * returns the struct proc_dir_entry for "/proc/tty/driver", and + * returns "serial" in residual. + */ +static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret, + const char **residual) +{ + const char *cp = name, *next; + struct proc_dir_entry *de; + unsigned int len; + + de = *ret; + if (!de) + de = &proc_root; + + while (1) { + next = strchr(cp, '/'); + if (!next) + break; + + len = next - cp; + de = pde_subdir_find(de, cp, len); + if (!de) { + WARN(1, "name '%s'\n", name); + return -ENOENT; + } + cp += len + 1; + } + *residual = cp; + *ret = de; + return 0; +} + +static int xlate_proc_name(const char *name, struct proc_dir_entry **ret, + const char **residual) +{ + int rv; + + spin_lock(&proc_subdir_lock); + rv = __xlate_proc_name(name, ret, residual); + spin_unlock(&proc_subdir_lock); + return rv; +} + +static DEFINE_IDA(proc_inum_ida); +static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */ + +#define PROC_DYNAMIC_FIRST 0xF0000000U + +/* + * Return an inode number between PROC_DYNAMIC_FIRST and + * 0xffffffff, or zero on failure. + */ +int proc_alloc_inum(unsigned int *inum) +{ + unsigned int i; + int error; + +retry: + if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL)) + return -ENOMEM; + + spin_lock_irq(&proc_inum_lock); + error = ida_get_new(&proc_inum_ida, &i); + spin_unlock_irq(&proc_inum_lock); + if (error == -EAGAIN) + goto retry; + else if (error) + return error; + + if (i > UINT_MAX - PROC_DYNAMIC_FIRST) { + spin_lock_irq(&proc_inum_lock); + ida_remove(&proc_inum_ida, i); + spin_unlock_irq(&proc_inum_lock); + return -ENOSPC; + } + *inum = PROC_DYNAMIC_FIRST + i; + return 0; +} + +void proc_free_inum(unsigned int inum) +{ + unsigned long flags; + spin_lock_irqsave(&proc_inum_lock, flags); + ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST); + spin_unlock_irqrestore(&proc_inum_lock, flags); +} + +/* + * Don't create negative dentries here, return -ENOENT by hand + * instead. + */ +struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir, + struct dentry *dentry) +{ + struct inode *inode; + + spin_lock(&proc_subdir_lock); + de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len); + if (de) { + pde_get(de); + spin_unlock(&proc_subdir_lock); + inode = proc_get_inode(dir->i_sb, de); + if (!inode) + return ERR_PTR(-ENOMEM); + d_set_d_op(dentry, &simple_dentry_operations); + d_add(dentry, inode); + return NULL; + } + spin_unlock(&proc_subdir_lock); + return ERR_PTR(-ENOENT); +} + +struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + return proc_lookup_de(PDE(dir), dir, dentry); +} + +/* + * This returns non-zero if at EOF, so that the /proc + * root directory can use this and check if it should + * continue with the <pid> entries.. + * + * Note that the VFS-layer doesn't care about the return + * value of the readdir() call, as long as it's non-negative + * for success.. + */ +int proc_readdir_de(struct proc_dir_entry *de, struct file *file, + struct dir_context *ctx) +{ + int i; + + if (!dir_emit_dots(file, ctx)) + return 0; + + spin_lock(&proc_subdir_lock); + de = pde_subdir_first(de); + i = ctx->pos - 2; + for (;;) { + if (!de) { + spin_unlock(&proc_subdir_lock); + return 0; + } + if (!i) + break; + de = pde_subdir_next(de); + i--; + } + + do { + struct proc_dir_entry *next; + pde_get(de); + spin_unlock(&proc_subdir_lock); + if (!dir_emit(ctx, de->name, de->namelen, + de->low_ino, de->mode >> 12)) { + pde_put(de); + return 0; + } + spin_lock(&proc_subdir_lock); + ctx->pos++; + next = pde_subdir_next(de); + pde_put(de); + de = next; + } while (de); + spin_unlock(&proc_subdir_lock); + return 1; +} + +int proc_readdir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + + return proc_readdir_de(PDE(inode), file, ctx); +} + +/* + * These are the generic /proc directory operations. They + * use the in-memory "struct proc_dir_entry" tree to parse + * the /proc directory. + */ +static const struct file_operations proc_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate = proc_readdir, +}; + +/* + * proc directories can do almost nothing.. + */ +static const struct inode_operations proc_dir_inode_operations = { + .lookup = proc_lookup, + .getattr = proc_getattr, + .setattr = proc_notify_change, +}; + +static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp) +{ + int ret; + + ret = proc_alloc_inum(&dp->low_ino); + if (ret) + return ret; + + spin_lock(&proc_subdir_lock); + dp->parent = dir; + if (pde_subdir_insert(dir, dp) == false) { + WARN(1, "proc_dir_entry '%s/%s' already registered\n", + dir->name, dp->name); + spin_unlock(&proc_subdir_lock); + proc_free_inum(dp->low_ino); + return -EEXIST; + } + spin_unlock(&proc_subdir_lock); + + return 0; +} + +static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, + const char *name, + umode_t mode, + nlink_t nlink) +{ + struct proc_dir_entry *ent = NULL; + const char *fn; + struct qstr qstr; + + if (xlate_proc_name(name, parent, &fn) != 0) + goto out; + qstr.name = fn; + qstr.len = strlen(fn); + if (qstr.len == 0 || qstr.len >= 256) { + WARN(1, "name len %u\n", qstr.len); + return NULL; + } + if (*parent == &proc_root && name_to_int(&qstr) != ~0U) { + WARN(1, "create '/proc/%s' by hand\n", qstr.name); + return NULL; + } + if (is_empty_pde(*parent)) { + WARN(1, "attempt to add to permanently empty directory"); + return NULL; + } + + ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL); + if (!ent) + goto out; + + memcpy(ent->name, fn, qstr.len + 1); + ent->namelen = qstr.len; + ent->mode = mode; + ent->nlink = nlink; + ent->subdir = RB_ROOT; + atomic_set(&ent->count, 1); + spin_lock_init(&ent->pde_unload_lock); + INIT_LIST_HEAD(&ent->pde_openers); +out: + return ent; +} + +struct proc_dir_entry *proc_symlink(const char *name, + struct proc_dir_entry *parent, const char *dest) +{ + struct proc_dir_entry *ent; + + ent = __proc_create(&parent, name, + (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1); + + if (ent) { + ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL); + if (ent->data) { + strcpy((char*)ent->data,dest); + ent->proc_iops = &proc_link_inode_operations; + if (proc_register(parent, ent) < 0) { + kfree(ent->data); + kfree(ent); + ent = NULL; + } + } else { + kfree(ent); + ent = NULL; + } + } + return ent; +} +EXPORT_SYMBOL(proc_symlink); + +struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode, + struct proc_dir_entry *parent, void *data) +{ + struct proc_dir_entry *ent; + + if (mode == 0) + mode = S_IRUGO | S_IXUGO; + + ent = __proc_create(&parent, name, S_IFDIR | mode, 2); + if (ent) { + ent->data = data; + ent->proc_fops = &proc_dir_operations; + ent->proc_iops = &proc_dir_inode_operations; + parent->nlink++; + if (proc_register(parent, ent) < 0) { + kfree(ent); + parent->nlink--; + ent = NULL; + } + } + return ent; +} +EXPORT_SYMBOL_GPL(proc_mkdir_data); + +struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode, + struct proc_dir_entry *parent) +{ + return proc_mkdir_data(name, mode, parent, NULL); +} +EXPORT_SYMBOL(proc_mkdir_mode); + +struct proc_dir_entry *proc_mkdir(const char *name, + struct proc_dir_entry *parent) +{ + return proc_mkdir_data(name, 0, parent, NULL); +} +EXPORT_SYMBOL(proc_mkdir); + +struct proc_dir_entry *proc_create_mount_point(const char *name) +{ + umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO; + struct proc_dir_entry *ent, *parent = NULL; + + ent = __proc_create(&parent, name, mode, 2); + if (ent) { + ent->data = NULL; + ent->proc_fops = NULL; + ent->proc_iops = NULL; + if (proc_register(parent, ent) < 0) { + kfree(ent); + parent->nlink--; + ent = NULL; + } + } + return ent; +} + +struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, + struct proc_dir_entry *parent, + const struct file_operations *proc_fops, + void *data) +{ + struct proc_dir_entry *pde; + if ((mode & S_IFMT) == 0) + mode |= S_IFREG; + + if (!S_ISREG(mode)) { + WARN_ON(1); /* use proc_mkdir() */ + return NULL; + } + + BUG_ON(proc_fops == NULL); + + if ((mode & S_IALLUGO) == 0) + mode |= S_IRUGO; + pde = __proc_create(&parent, name, mode, 1); + if (!pde) + goto out; + pde->proc_fops = proc_fops; + pde->data = data; + pde->proc_iops = &proc_file_inode_operations; + if (proc_register(parent, pde) < 0) + goto out_free; + return pde; +out_free: + kfree(pde); +out: + return NULL; +} +EXPORT_SYMBOL(proc_create_data); + +void proc_set_size(struct proc_dir_entry *de, loff_t size) +{ + de->size = size; +} +EXPORT_SYMBOL(proc_set_size); + +void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid) +{ + de->uid = uid; + de->gid = gid; +} +EXPORT_SYMBOL(proc_set_user); + +static void free_proc_entry(struct proc_dir_entry *de) +{ + proc_free_inum(de->low_ino); + + if (S_ISLNK(de->mode)) + kfree(de->data); + kfree(de); +} + +void pde_put(struct proc_dir_entry *pde) +{ + if (atomic_dec_and_test(&pde->count)) + free_proc_entry(pde); +} + +/* + * Remove a /proc entry and free it if it's not currently in use. + */ +void remove_proc_entry(const char *name, struct proc_dir_entry *parent) +{ + struct proc_dir_entry *de = NULL; + const char *fn = name; + unsigned int len; + + spin_lock(&proc_subdir_lock); + if (__xlate_proc_name(name, &parent, &fn) != 0) { + spin_unlock(&proc_subdir_lock); + return; + } + len = strlen(fn); + + de = pde_subdir_find(parent, fn, len); + if (de) + rb_erase(&de->subdir_node, &parent->subdir); + spin_unlock(&proc_subdir_lock); + if (!de) { + WARN(1, "name '%s'\n", name); + return; + } + + proc_entry_rundown(de); + + if (S_ISDIR(de->mode)) + parent->nlink--; + de->nlink = 0; + WARN(pde_subdir_first(de), + "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n", + __func__, de->parent->name, de->name, pde_subdir_first(de)->name); + pde_put(de); +} +EXPORT_SYMBOL(remove_proc_entry); + +int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) +{ + struct proc_dir_entry *root = NULL, *de, *next; + const char *fn = name; + unsigned int len; + + spin_lock(&proc_subdir_lock); + if (__xlate_proc_name(name, &parent, &fn) != 0) { + spin_unlock(&proc_subdir_lock); + return -ENOENT; + } + len = strlen(fn); + + root = pde_subdir_find(parent, fn, len); + if (!root) { + spin_unlock(&proc_subdir_lock); + return -ENOENT; + } + rb_erase(&root->subdir_node, &parent->subdir); + + de = root; + while (1) { + next = pde_subdir_first(de); + if (next) { + rb_erase(&next->subdir_node, &de->subdir); + de = next; + continue; + } + spin_unlock(&proc_subdir_lock); + + proc_entry_rundown(de); + next = de->parent; + if (S_ISDIR(de->mode)) + next->nlink--; + de->nlink = 0; + if (de == root) + break; + pde_put(de); + + spin_lock(&proc_subdir_lock); + de = next; + } + pde_put(root); + return 0; +} +EXPORT_SYMBOL(remove_proc_subtree); + +void *proc_get_parent_data(const struct inode *inode) +{ + struct proc_dir_entry *de = PDE(inode); + return de->parent->data; +} +EXPORT_SYMBOL_GPL(proc_get_parent_data); + +void proc_remove(struct proc_dir_entry *de) +{ + if (de) + remove_proc_subtree(de->name, de->parent); +} +EXPORT_SYMBOL(proc_remove); + +void *PDE_DATA(const struct inode *inode) +{ + return __PDE_DATA(inode); +} +EXPORT_SYMBOL(PDE_DATA); |