--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff