+static struct ctl_dir *find_subdir(struct ctl_dir *dir,
+ const char *name, int namelen)
+{
+ struct ctl_table_header *head;
+ struct ctl_table *entry;
+
+ entry = find_entry(&head, dir, name, namelen);
+ if (!entry)
+ return ERR_PTR(-ENOENT);
+ if (!S_ISDIR(entry->mode))
+ return ERR_PTR(-ENOTDIR);
+ return container_of(head, struct ctl_dir, header);
+}
+
+static struct ctl_dir *new_dir(struct ctl_table_set *set,
+ const char *name, int namelen)
+{
+ struct ctl_table *table;
+ struct ctl_dir *new;
+ struct ctl_node *node;
+ char *new_name;
+
+ new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) +
+ sizeof(struct ctl_table)*2 + namelen + 1,
+ GFP_KERNEL);
+ if (!new)
+ return NULL;
+
+ node = (struct ctl_node *)(new + 1);
+ table = (struct ctl_table *)(node + 1);
+ new_name = (char *)(table + 2);
+ memcpy(new_name, name, namelen);
+ new_name[namelen] = '\0';
+ table[0].procname = new_name;
+ table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
+ init_header(&new->header, set->dir.header.root, set, node, table);
+
+ return new;
+}
+
+/**
+ * get_subdir - find or create a subdir with the specified name.
+ * @dir: Directory to create the subdirectory in
+ * @name: The name of the subdirectory to find or create
+ * @namelen: The length of name
+ *
+ * Takes a directory with an elevated reference count so we know that
+ * if we drop the lock the directory will not go away. Upon success
+ * the reference is moved from @dir to the returned subdirectory.
+ * Upon error an error code is returned and the reference on @dir is
+ * simply dropped.
+ */
+static struct ctl_dir *get_subdir(struct ctl_dir *dir,
+ const char *name, int namelen)
+{
+ struct ctl_table_set *set = dir->header.set;
+ struct ctl_dir *subdir, *new = NULL;
+ int err;
+
+ spin_lock(&sysctl_lock);
+ subdir = find_subdir(dir, name, namelen);
+ if (!IS_ERR(subdir))
+ goto found;
+ if (PTR_ERR(subdir) != -ENOENT)
+ goto failed;
+
+ spin_unlock(&sysctl_lock);
+ new = new_dir(set, name, namelen);
+ spin_lock(&sysctl_lock);
+ subdir = ERR_PTR(-ENOMEM);
+ if (!new)
+ goto failed;
+
+ /* Was the subdir added while we dropped the lock? */
+ subdir = find_subdir(dir, name, namelen);
+ if (!IS_ERR(subdir))
+ goto found;
+ if (PTR_ERR(subdir) != -ENOENT)
+ goto failed;
+
+ /* Nope. Use the our freshly made directory entry. */
+ err = insert_header(dir, &new->header);
+ subdir = ERR_PTR(err);
+ if (err)
+ goto failed;
+ subdir = new;
+found:
+ subdir->header.nreg++;
+failed:
+ if (unlikely(IS_ERR(subdir))) {
+ printk(KERN_ERR "sysctl could not get directory: ");
+ sysctl_print_dir(dir);
+ printk(KERN_CONT "/%*.*s %ld\n",
+ namelen, namelen, name, PTR_ERR(subdir));
+ }
+ drop_sysctl_table(&dir->header);
+ if (new)
+ drop_sysctl_table(&new->header);
+ spin_unlock(&sysctl_lock);
+ return subdir;
+}
+
+static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir)
+{
+ struct ctl_dir *parent;
+ const char *procname;
+ if (!dir->header.parent)
+ return &set->dir;
+ parent = xlate_dir(set, dir->header.parent);
+ if (IS_ERR(parent))
+ return parent;
+ procname = dir->header.ctl_table[0].procname;
+ return find_subdir(parent, procname, strlen(procname));
+}
+
+static int sysctl_follow_link(struct ctl_table_header **phead,
+ struct ctl_table **pentry, struct nsproxy *namespaces)
+{
+ struct ctl_table_header *head;
+ struct ctl_table_root *root;
+ struct ctl_table_set *set;
+ struct ctl_table *entry;
+ struct ctl_dir *dir;
+ int ret;
+
+ ret = 0;
+ spin_lock(&sysctl_lock);
+ root = (*pentry)->data;
+ set = lookup_header_set(root, namespaces);
+ dir = xlate_dir(set, (*phead)->parent);
+ if (IS_ERR(dir))
+ ret = PTR_ERR(dir);
+ else {
+ const char *procname = (*pentry)->procname;
+ head = NULL;
+ entry = find_entry(&head, dir, procname, strlen(procname));
+ ret = -ENOENT;
+ if (entry && use_table(head)) {
+ unuse_table(*phead);
+ *phead = head;
+ *pentry = entry;
+ ret = 0;
+ }
+ }
+
+ spin_unlock(&sysctl_lock);
+ return ret;
+}
+
+static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ printk(KERN_ERR "sysctl table check failed: %s/%s %pV\n",
+ path, table->procname, &vaf);
+
+ va_end(args);
+ return -EINVAL;
+}
+
+static int sysctl_check_table(const char *path, struct ctl_table *table)
+{
+ int err = 0;
+ for (; table->procname; table++) {
+ if (table->child)
+ err = sysctl_err(path, table, "Not a file");
+
+ if ((table->proc_handler == proc_dostring) ||
+ (table->proc_handler == proc_dointvec) ||
+ (table->proc_handler == proc_dointvec_minmax) ||
+ (table->proc_handler == proc_dointvec_jiffies) ||
+ (table->proc_handler == proc_dointvec_userhz_jiffies) ||
+ (table->proc_handler == proc_dointvec_ms_jiffies) ||
+ (table->proc_handler == proc_doulongvec_minmax) ||
+ (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
+ if (!table->data)
+ err = sysctl_err(path, table, "No data");
+ if (!table->maxlen)
+ err = sysctl_err(path, table, "No maxlen");
+ }
+ if (!table->proc_handler)
+ err = sysctl_err(path, table, "No proc_handler");
+
+ if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode)
+ err = sysctl_err(path, table, "bogus .mode 0%o",
+ table->mode);
+ }
+ return err;
+}
+
+static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
+ struct ctl_table_root *link_root)
+{
+ struct ctl_table *link_table, *entry, *link;
+ struct ctl_table_header *links;
+ struct ctl_node *node;
+ char *link_name;
+ int nr_entries, name_bytes;
+
+ name_bytes = 0;
+ nr_entries = 0;
+ for (entry = table; entry->procname; entry++) {
+ nr_entries++;
+ name_bytes += strlen(entry->procname) + 1;
+ }
+
+ links = kzalloc(sizeof(struct ctl_table_header) +
+ sizeof(struct ctl_node)*nr_entries +
+ sizeof(struct ctl_table)*(nr_entries + 1) +
+ name_bytes,
+ GFP_KERNEL);
+
+ if (!links)
+ return NULL;
+
+ node = (struct ctl_node *)(links + 1);
+ link_table = (struct ctl_table *)(node + nr_entries);
+ link_name = (char *)&link_table[nr_entries + 1];
+
+ for (link = link_table, entry = table; entry->procname; link++, entry++) {
+ int len = strlen(entry->procname) + 1;
+ memcpy(link_name, entry->procname, len);
+ link->procname = link_name;
+ link->mode = S_IFLNK|S_IRWXUGO;
+ link->data = link_root;
+ link_name += len;
+ }
+ init_header(links, dir->header.root, dir->header.set, node, link_table);
+ links->nreg = nr_entries;
+
+ return links;
+}
+
+static bool get_links(struct ctl_dir *dir,
+ struct ctl_table *table, struct ctl_table_root *link_root)
+{
+ struct ctl_table_header *head;
+ struct ctl_table *entry, *link;
+
+ /* Are there links available for every entry in table? */
+ for (entry = table; entry->procname; entry++) {
+ const char *procname = entry->procname;
+ link = find_entry(&head, dir, procname, strlen(procname));
+ if (!link)
+ return false;
+ if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
+ continue;
+ if (S_ISLNK(link->mode) && (link->data == link_root))
+ continue;
+ return false;
+ }
+
+ /* The checks passed. Increase the registration count on the links */
+ for (entry = table; entry->procname; entry++) {
+ const char *procname = entry->procname;
+ link = find_entry(&head, dir, procname, strlen(procname));
+ head->nreg++;
+ }
+ return true;
+}
+
+static int insert_links(struct ctl_table_header *head)
+{
+ struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+ struct ctl_dir *core_parent = NULL;
+ struct ctl_table_header *links;
+ int err;
+
+ if (head->set == root_set)
+ return 0;
+
+ core_parent = xlate_dir(root_set, head->parent);
+ if (IS_ERR(core_parent))
+ return 0;
+
+ if (get_links(core_parent, head->ctl_table, head->root))
+ return 0;
+
+ core_parent->header.nreg++;
+ spin_unlock(&sysctl_lock);
+
+ links = new_links(core_parent, head->ctl_table, head->root);
+
+ spin_lock(&sysctl_lock);
+ err = -ENOMEM;
+ if (!links)
+ goto out;
+
+ err = 0;
+ if (get_links(core_parent, head->ctl_table, head->root)) {
+ kfree(links);
+ goto out;
+ }
+
+ err = insert_header(core_parent, links);
+ if (err)
+ kfree(links);
+out:
+ drop_sysctl_table(&core_parent->header);
+ return err;
+}
+
+/**
+ * __register_sysctl_table - register a leaf sysctl table
+ * @set: Sysctl tree to register on
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * The members of the &struct ctl_table structure are used as follows:
+ *
+ * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
+ * enter a sysctl file
+ *
+ * data - a pointer to data for use by proc_handler
+ *
+ * maxlen - the maximum size in bytes of the data
+ *
+ * mode - the file permissions for the /proc/sys file
+ *
+ * child - must be %NULL.
+ *
+ * proc_handler - the text handler routine (described below)
+ *
+ * extra1, extra2 - extra pointers usable by the proc handler routines
+ *
+ * Leaf nodes in the sysctl tree will be represented by a single file
+ * under /proc; non-leaf nodes will be represented by directories.
+ *
+ * There must be a proc_handler routine for any terminal nodes.
+ * Several default handlers are available to cover common cases -
+ *
+ * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
+ * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
+ * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
+ *
+ * It is the handler's job to read the input buffer from user memory
+ * and process it. The handler should return 0 on success.
+ *
+ * This routine returns %NULL on a failure to register, and a pointer
+ * to the table header on success.
+ */
+struct ctl_table_header *__register_sysctl_table(
+ struct ctl_table_set *set,
+ const char *path, struct ctl_table *table)
+{
+ struct ctl_table_root *root = set->dir.header.root;
+ struct ctl_table_header *header;
+ const char *name, *nextname;
+ struct ctl_dir *dir;
+ struct ctl_table *entry;
+ struct ctl_node *node;
+ int nr_entries = 0;
+
+ for (entry = table; entry->procname; entry++)
+ nr_entries++;
+
+ header = kzalloc(sizeof(struct ctl_table_header) +
+ sizeof(struct ctl_node)*nr_entries, GFP_KERNEL);
+ if (!header)
+ return NULL;
+
+ node = (struct ctl_node *)(header + 1);
+ init_header(header, root, set, node, table);
+ if (sysctl_check_table(path, table))
+ goto fail;
+
+ spin_lock(&sysctl_lock);
+ dir = &set->dir;
+ /* Reference moved down the diretory tree get_subdir */
+ dir->header.nreg++;
+ spin_unlock(&sysctl_lock);
+
+ /* Find the directory for the ctl_table */
+ for (name = path; name; name = nextname) {
+ int namelen;
+ nextname = strchr(name, '/');
+ if (nextname) {
+ namelen = nextname - name;
+ nextname++;
+ } else {
+ namelen = strlen(name);
+ }
+ if (namelen == 0)
+ continue;
+
+ dir = get_subdir(dir, name, namelen);
+ if (IS_ERR(dir))
+ goto fail;
+ }
+
+ spin_lock(&sysctl_lock);
+ if (insert_header(dir, header))
+ goto fail_put_dir_locked;
+
+ drop_sysctl_table(&dir->header);
+ spin_unlock(&sysctl_lock);
+
+ return header;
+
+fail_put_dir_locked:
+ drop_sysctl_table(&dir->header);
+ spin_unlock(&sysctl_lock);
+fail:
+ kfree(header);
+ dump_stack();
+ return NULL;
+}
+
+/**
+ * register_sysctl - register a sysctl table
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the table structure
+ *
+ * Register a sysctl table. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See __register_sysctl_table for more details.
+ */
+struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
+{
+ return __register_sysctl_table(&sysctl_table_root.default_set,
+ path, table);
+}
+EXPORT_SYMBOL(register_sysctl);
+
+static char *append_path(const char *path, char *pos, const char *name)
+{
+ int namelen;
+ namelen = strlen(name);
+ if (((pos - path) + namelen + 2) >= PATH_MAX)
+ return NULL;
+ memcpy(pos, name, namelen);
+ pos[namelen] = '/';
+ pos[namelen + 1] = '\0';
+ pos += namelen + 1;
+ return pos;
+}
+
+static int count_subheaders(struct ctl_table *table)
+{
+ int has_files = 0;
+ int nr_subheaders = 0;
+ struct ctl_table *entry;
+
+ /* special case: no directory and empty directory */
+ if (!table || !table->procname)
+ return 1;
+
+ for (entry = table; entry->procname; entry++) {
+ if (entry->child)
+ nr_subheaders += count_subheaders(entry->child);
+ else
+ has_files = 1;
+ }
+ return nr_subheaders + has_files;
+}
+
+static int register_leaf_sysctl_tables(const char *path, char *pos,
+ struct ctl_table_header ***subheader, struct ctl_table_set *set,
+ struct ctl_table *table)
+{
+ struct ctl_table *ctl_table_arg = NULL;
+ struct ctl_table *entry, *files;
+ int nr_files = 0;
+ int nr_dirs = 0;
+ int err = -ENOMEM;
+
+ for (entry = table; entry->procname; entry++) {
+ if (entry->child)
+ nr_dirs++;
+ else
+ nr_files++;
+ }
+
+ files = table;
+ /* If there are mixed files and directories we need a new table */
+ if (nr_dirs && nr_files) {
+ struct ctl_table *new;
+ files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1),
+ GFP_KERNEL);
+ if (!files)
+ goto out;
+
+ ctl_table_arg = files;
+ for (new = files, entry = table; entry->procname; entry++) {
+ if (entry->child)
+ continue;
+ *new = *entry;
+ new++;
+ }
+ }
+
+ /* Register everything except a directory full of subdirectories */
+ if (nr_files || !nr_dirs) {
+ struct ctl_table_header *header;
+ header = __register_sysctl_table(set, path, files);
+ if (!header) {
+ kfree(ctl_table_arg);
+ goto out;
+ }
+
+ /* Remember if we need to free the file table */
+ header->ctl_table_arg = ctl_table_arg;
+ **subheader = header;
+ (*subheader)++;
+ }
+
+ /* Recurse into the subdirectories. */
+ for (entry = table; entry->procname; entry++) {
+ char *child_pos;
+
+ if (!entry->child)
+ continue;
+
+ err = -ENAMETOOLONG;
+ child_pos = append_path(path, pos, entry->procname);
+ if (!child_pos)
+ goto out;
+
+ err = register_leaf_sysctl_tables(path, child_pos, subheader,
+ set, entry->child);
+ pos[0] = '\0';
+ if (err)
+ goto out;
+ }
+ err = 0;
+out:
+ /* On failure our caller will unregister all registered subheaders */
+ return err;
+}
+
+/**
+ * __register_sysctl_paths - register a sysctl table hierarchy
+ * @set: Sysctl tree to register on
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See __register_sysctl_table for more details.
+ */
+struct ctl_table_header *__register_sysctl_paths(
+ struct ctl_table_set *set,
+ const struct ctl_path *path, struct ctl_table *table)
+{
+ struct ctl_table *ctl_table_arg = table;
+ int nr_subheaders = count_subheaders(table);
+ struct ctl_table_header *header = NULL, **subheaders, **subheader;
+ const struct ctl_path *component;
+ char *new_path, *pos;
+
+ pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (!new_path)
+ return NULL;
+
+ pos[0] = '\0';
+ for (component = path; component->procname; component++) {
+ pos = append_path(new_path, pos, component->procname);
+ if (!pos)
+ goto out;
+ }
+ while (table->procname && table->child && !table[1].procname) {
+ pos = append_path(new_path, pos, table->procname);
+ if (!pos)
+ goto out;
+ table = table->child;
+ }
+ if (nr_subheaders == 1) {
+ header = __register_sysctl_table(set, new_path, table);
+ if (header)
+ header->ctl_table_arg = ctl_table_arg;
+ } else {
+ header = kzalloc(sizeof(*header) +
+ sizeof(*subheaders)*nr_subheaders, GFP_KERNEL);
+ if (!header)
+ goto out;
+
+ subheaders = (struct ctl_table_header **) (header + 1);
+ subheader = subheaders;
+ header->ctl_table_arg = ctl_table_arg;
+
+ if (register_leaf_sysctl_tables(new_path, pos, &subheader,
+ set, table))
+ goto err_register_leaves;
+ }
+
+out:
+ kfree(new_path);
+ return header;
+
+err_register_leaves:
+ while (subheader > subheaders) {
+ struct ctl_table_header *subh = *(--subheader);
+ struct ctl_table *table = subh->ctl_table_arg;
+ unregister_sysctl_table(subh);
+ kfree(table);
+ }
+ kfree(header);
+ header = NULL;
+ goto out;
+}
+
+/**
+ * register_sysctl_table_path - register a sysctl table hierarchy
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See __register_sysctl_paths for more details.
+ */
+struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
+ struct ctl_table *table)
+{
+ return __register_sysctl_paths(&sysctl_table_root.default_set,
+ path, table);
+}
+EXPORT_SYMBOL(register_sysctl_paths);
+
+/**
+ * register_sysctl_table - register a sysctl table hierarchy
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See register_sysctl_paths for more details.
+ */
+struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
+{
+ static const struct ctl_path null_path[] = { {} };
+
+ return register_sysctl_paths(null_path, table);
+}
+EXPORT_SYMBOL(register_sysctl_table);
+
+static void put_links(struct ctl_table_header *header)
+{
+ struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+ struct ctl_table_root *root = header->root;
+ struct ctl_dir *parent = header->parent;
+ struct ctl_dir *core_parent;
+ struct ctl_table *entry;
+
+ if (header->set == root_set)
+ return;
+
+ core_parent = xlate_dir(root_set, parent);
+ if (IS_ERR(core_parent))
+ return;
+
+ for (entry = header->ctl_table; entry->procname; entry++) {
+ struct ctl_table_header *link_head;
+ struct ctl_table *link;
+ const char *name = entry->procname;
+
+ link = find_entry(&link_head, core_parent, name, strlen(name));
+ if (link &&
+ ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) ||
+ (S_ISLNK(link->mode) && (link->data == root)))) {
+ drop_sysctl_table(link_head);
+ }
+ else {
+ printk(KERN_ERR "sysctl link missing during unregister: ");
+ sysctl_print_dir(parent);
+ printk(KERN_CONT "/%s\n", name);
+ }
+ }
+}
+
+static void drop_sysctl_table(struct ctl_table_header *header)
+{
+ struct ctl_dir *parent = header->parent;
+
+ if (--header->nreg)
+ return;
+
+ put_links(header);
+ start_unregistering(header);
+ if (!--header->count)
+ kfree_rcu(header, rcu);
+
+ if (parent)
+ drop_sysctl_table(&parent->header);
+}
+
+/**
+ * unregister_sysctl_table - unregister a sysctl table hierarchy
+ * @header: the header returned from register_sysctl_table
+ *
+ * Unregisters the sysctl table and all children. proc entries may not
+ * actually be removed until they are no longer used by anyone.
+ */
+void unregister_sysctl_table(struct ctl_table_header * header)
+{
+ int nr_subheaders;
+ might_sleep();
+
+ if (header == NULL)
+ return;
+
+ nr_subheaders = count_subheaders(header->ctl_table_arg);
+ if (unlikely(nr_subheaders > 1)) {
+ struct ctl_table_header **subheaders;
+ int i;
+
+ subheaders = (struct ctl_table_header **)(header + 1);
+ for (i = nr_subheaders -1; i >= 0; i--) {
+ struct ctl_table_header *subh = subheaders[i];
+ struct ctl_table *table = subh->ctl_table_arg;
+ unregister_sysctl_table(subh);
+ kfree(table);
+ }
+ kfree(header);
+ return;
+ }
+
+ spin_lock(&sysctl_lock);
+ drop_sysctl_table(header);
+ spin_unlock(&sysctl_lock);
+}
+EXPORT_SYMBOL(unregister_sysctl_table);
+
+void setup_sysctl_set(struct ctl_table_set *set,
+ struct ctl_table_root *root,
+ int (*is_seen)(struct ctl_table_set *))
+{
+ memset(set, 0, sizeof(*set));
+ set->is_seen = is_seen;
+ init_header(&set->dir.header, root, set, NULL, root_table);
+}
+
+void retire_sysctl_set(struct ctl_table_set *set)
+{
+ WARN_ON(!RB_EMPTY_ROOT(&set->dir.root));
+}
+