]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - fs/proc/proc_sysctl.c
sysctl: register only tables of sysctl files
[mv-sheeva.git] / fs / proc / proc_sysctl.c
index a6b62173d4c310e4fa4b131a214043667fa67726..6bab2ae9e3952669c59158182c3fcb91d643cb24 100644 (file)
@@ -7,6 +7,7 @@
 #include <linux/proc_fs.h>
 #include <linux/security.h>
 #include <linux/namei.h>
+#include <linux/module.h>
 #include "internal.h"
 
 static const struct dentry_operations proc_sys_dentry_operations;
@@ -24,6 +25,209 @@ void proc_sys_poll_notify(struct ctl_table_poll *poll)
        wake_up_interruptible(&poll->wait);
 }
 
+static struct ctl_table root_table[1];
+static struct ctl_table_root sysctl_table_root;
+static struct ctl_table_header root_table_header = {
+       {{.count = 1,
+       .ctl_table = root_table,
+       .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
+       .root = &sysctl_table_root,
+       .set = &sysctl_table_root.default_set,
+};
+static struct ctl_table_root sysctl_table_root = {
+       .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
+       .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
+};
+
+static DEFINE_SPINLOCK(sysctl_lock);
+
+/* called under sysctl_lock */
+static int use_table(struct ctl_table_header *p)
+{
+       if (unlikely(p->unregistering))
+               return 0;
+       p->used++;
+       return 1;
+}
+
+/* called under sysctl_lock */
+static void unuse_table(struct ctl_table_header *p)
+{
+       if (!--p->used)
+               if (unlikely(p->unregistering))
+                       complete(p->unregistering);
+}
+
+/* called under sysctl_lock, will reacquire if has to wait */
+static void start_unregistering(struct ctl_table_header *p)
+{
+       /*
+        * if p->used is 0, nobody will ever touch that entry again;
+        * we'll eliminate all paths to it before dropping sysctl_lock
+        */
+       if (unlikely(p->used)) {
+               struct completion wait;
+               init_completion(&wait);
+               p->unregistering = &wait;
+               spin_unlock(&sysctl_lock);
+               wait_for_completion(&wait);
+               spin_lock(&sysctl_lock);
+       } else {
+               /* anything non-NULL; we'll never dereference it */
+               p->unregistering = ERR_PTR(-EINVAL);
+       }
+       /*
+        * do not remove from the list until nobody holds it; walking the
+        * list in do_sysctl() relies on that.
+        */
+       list_del_init(&p->ctl_entry);
+}
+
+static void sysctl_head_get(struct ctl_table_header *head)
+{
+       spin_lock(&sysctl_lock);
+       head->count++;
+       spin_unlock(&sysctl_lock);
+}
+
+void sysctl_head_put(struct ctl_table_header *head)
+{
+       spin_lock(&sysctl_lock);
+       if (!--head->count)
+               kfree_rcu(head, rcu);
+       spin_unlock(&sysctl_lock);
+}
+
+static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
+{
+       if (!head)
+               BUG();
+       spin_lock(&sysctl_lock);
+       if (!use_table(head))
+               head = ERR_PTR(-ENOENT);
+       spin_unlock(&sysctl_lock);
+       return head;
+}
+
+static void sysctl_head_finish(struct ctl_table_header *head)
+{
+       if (!head)
+               return;
+       spin_lock(&sysctl_lock);
+       unuse_table(head);
+       spin_unlock(&sysctl_lock);
+}
+
+static struct ctl_table_set *
+lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
+{
+       struct ctl_table_set *set = &root->default_set;
+       if (root->lookup)
+               set = root->lookup(root, namespaces);
+       return set;
+}
+
+static struct list_head *
+lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
+{
+       struct ctl_table_set *set = lookup_header_set(root, namespaces);
+       return &set->list;
+}
+
+static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
+                                               struct ctl_table_header *prev)
+{
+       struct ctl_table_root *root;
+       struct list_head *header_list;
+       struct ctl_table_header *head;
+       struct list_head *tmp;
+
+       spin_lock(&sysctl_lock);
+       if (prev) {
+               head = prev;
+               tmp = &prev->ctl_entry;
+               unuse_table(prev);
+               goto next;
+       }
+       tmp = &root_table_header.ctl_entry;
+       for (;;) {
+               head = list_entry(tmp, struct ctl_table_header, ctl_entry);
+
+               if (!use_table(head))
+                       goto next;
+               spin_unlock(&sysctl_lock);
+               return head;
+       next:
+               root = head->root;
+               tmp = tmp->next;
+               header_list = lookup_header_list(root, namespaces);
+               if (tmp != header_list)
+                       continue;
+
+               do {
+                       root = list_entry(root->root_list.next,
+                                       struct ctl_table_root, root_list);
+                       if (root == &sysctl_table_root)
+                               goto out;
+                       header_list = lookup_header_list(root, namespaces);
+               } while (list_empty(header_list));
+               tmp = header_list->next;
+       }
+out:
+       spin_unlock(&sysctl_lock);
+       return NULL;
+}
+
+static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
+{
+       return __sysctl_head_next(current->nsproxy, prev);
+}
+
+void register_sysctl_root(struct ctl_table_root *root)
+{
+       spin_lock(&sysctl_lock);
+       list_add_tail(&root->root_list, &sysctl_table_root.root_list);
+       spin_unlock(&sysctl_lock);
+}
+
+/*
+ * sysctl_perm does NOT grant the superuser all rights automatically, because
+ * some sysctl variables are readonly even to root.
+ */
+
+static int test_perm(int mode, int op)
+{
+       if (!current_euid())
+               mode >>= 6;
+       else if (in_egroup_p(0))
+               mode >>= 3;
+       if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
+               return 0;
+       return -EACCES;
+}
+
+static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
+{
+       int mode;
+
+       if (root->permissions)
+               mode = root->permissions(root, current->nsproxy, table);
+       else
+               mode = table->mode;
+
+       return test_perm(mode, op);
+}
+
+static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
+{
+       for (; table->procname; table++) {
+               table->parent = parent;
+               if (table->child)
+                       sysctl_set_parent(table, table->child);
+       }
+}
+
+
 static struct inode *proc_sys_make_inode(struct super_block *sb,
                struct ctl_table_header *head, struct ctl_table *table)
 {
@@ -49,7 +253,6 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
                inode->i_fop = &proc_sys_file_operations;
        } else {
                inode->i_mode |= S_IFDIR;
-               clear_nlink(inode);
                inode->i_op = &proc_sys_dir_operations;
                inode->i_fop = &proc_sys_dir_file_operations;
        }
@@ -59,17 +262,11 @@ out:
 
 static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
 {
-       int len;
        for ( ; p->procname; p++) {
-
-               if (!p->procname)
-                       continue;
-
-               len = strlen(p->procname);
-               if (len != name->len)
+               if (strlen(p->procname) != name->len)
                        continue;
 
-               if (memcmp(p->procname, name->name, len) != 0)
+               if (memcmp(p->procname, name->name, name->len) != 0)
                        continue;
 
                /* I have a match */
@@ -266,10 +463,6 @@ static int scan(struct ctl_table_header *head, ctl_table *table,
        for (; table->procname; table++, (*pos)++) {
                int res;
 
-               /* Can't do anything without a proc name */
-               if (!table->procname)
-                       continue;
-
                if (*pos < file->f_pos)
                        continue;
 
@@ -445,6 +638,21 @@ static int proc_sys_delete(const struct dentry *dentry)
        return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
 }
 
+static int sysctl_is_seen(struct ctl_table_header *p)
+{
+       struct ctl_table_set *set = p->set;
+       int res;
+       spin_lock(&sysctl_lock);
+       if (p->unregistering)
+               res = 0;
+       else if (!set->is_seen)
+               res = 1;
+       else
+               res = set->is_seen(set);
+       spin_unlock(&sysctl_lock);
+       return res;
+}
+
 static int proc_sys_compare(const struct dentry *parent,
                const struct inode *pinode,
                const struct dentry *dentry, const struct inode *inode,
@@ -470,6 +678,635 @@ static const struct dentry_operations proc_sys_dentry_operations = {
        .d_compare      = proc_sys_compare,
 };
 
+static struct ctl_table *is_branch_in(struct ctl_table *branch,
+                                     struct ctl_table *table)
+{
+       struct ctl_table *p;
+       const char *s = branch->procname;
+
+       /* branch should have named subdirectory as its first element */
+       if (!s || !branch->child)
+               return NULL;
+
+       /* ... and nothing else */
+       if (branch[1].procname)
+               return NULL;
+
+       /* table should contain subdirectory with the same name */
+       for (p = table; p->procname; p++) {
+               if (!p->child)
+                       continue;
+               if (p->procname && strcmp(p->procname, s) == 0)
+                       return p;
+       }
+       return NULL;
+}
+
+/* see if attaching q to p would be an improvement */
+static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
+{
+       struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
+       struct ctl_table *next;
+       int is_better = 0;
+       int not_in_parent = !p->attached_by;
+
+       while ((next = is_branch_in(by, to)) != NULL) {
+               if (by == q->attached_by)
+                       is_better = 1;
+               if (to == p->attached_by)
+                       not_in_parent = 1;
+               by = by->child;
+               to = next->child;
+       }
+
+       if (is_better && not_in_parent) {
+               q->attached_by = by;
+               q->attached_to = to;
+               q->parent = p;
+       }
+}
+
+#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
+static int sysctl_depth(struct ctl_table *table)
+{
+       struct ctl_table *tmp;
+       int depth;
+
+       depth = 0;
+       for (tmp = table; tmp->parent; tmp = tmp->parent)
+               depth++;
+
+       return depth;
+}
+
+static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
+{
+       int i;
+
+       for (i = 0; table && i < n; i++)
+               table = table->parent;
+
+       return table;
+}
+
+
+static void sysctl_print_path(struct ctl_table *table)
+{
+       struct ctl_table *tmp;
+       int depth, i;
+       depth = sysctl_depth(table);
+       if (table->procname) {
+               for (i = depth; i >= 0; i--) {
+                       tmp = sysctl_parent(table, i);
+                       printk("/%s", tmp->procname?tmp->procname:"");
+               }
+       }
+       printk(" ");
+}
+
+static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
+                                               struct ctl_table *table)
+{
+       struct ctl_table_header *head;
+       struct ctl_table *ref, *test;
+       int depth, cur_depth;
+
+       depth = sysctl_depth(table);
+
+       for (head = __sysctl_head_next(namespaces, NULL); head;
+            head = __sysctl_head_next(namespaces, head)) {
+               cur_depth = depth;
+               ref = head->ctl_table;
+repeat:
+               test = sysctl_parent(table, cur_depth);
+               for (; ref->procname; ref++) {
+                       int match = 0;
+                       if (cur_depth && !ref->child)
+                               continue;
+
+                       if (test->procname && ref->procname &&
+                           (strcmp(test->procname, ref->procname) == 0))
+                                       match++;
+
+                       if (match) {
+                               if (cur_depth != 0) {
+                                       cur_depth--;
+                                       ref = ref->child;
+                                       goto repeat;
+                               }
+                               goto out;
+                       }
+               }
+       }
+       ref = NULL;
+out:
+       sysctl_head_finish(head);
+       return ref;
+}
+
+static void set_fail(const char **fail, struct ctl_table *table, const char *str)
+{
+       if (*fail) {
+               printk(KERN_ERR "sysctl table check failed: ");
+               sysctl_print_path(table);
+               printk(" %s\n", *fail);
+               dump_stack();
+       }
+       *fail = str;
+}
+
+static void sysctl_check_leaf(struct nsproxy *namespaces,
+                               struct ctl_table *table, const char **fail)
+{
+       struct ctl_table *ref;
+
+       ref = sysctl_check_lookup(namespaces, table);
+       if (ref && (ref != table))
+               set_fail(fail, table, "Sysctl already exists");
+}
+
+static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
+{
+       int error = 0;
+       for (; table->procname; table++) {
+               const char *fail = NULL;
+
+               if (table->parent) {
+                       if (!table->parent->procname)
+                               set_fail(&fail, table, "Parent without procname");
+               }
+               if (table->child) {
+                       if (table->data)
+                               set_fail(&fail, table, "Directory with data?");
+                       if (table->maxlen)
+                               set_fail(&fail, table, "Directory with maxlen?");
+                       if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
+                               set_fail(&fail, table, "Writable sysctl directory");
+                       if (table->proc_handler)
+                               set_fail(&fail, table, "Directory with proc_handler");
+                       if (table->extra1)
+                               set_fail(&fail, table, "Directory with extra1");
+                       if (table->extra2)
+                               set_fail(&fail, table, "Directory with extra2");
+               } else {
+                       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)
+                                       set_fail(&fail, table, "No data");
+                               if (!table->maxlen)
+                                       set_fail(&fail, table, "No maxlen");
+                       }
+#ifdef CONFIG_PROC_SYSCTL
+                       if (!table->proc_handler)
+                               set_fail(&fail, table, "No proc_handler");
+#endif
+                       sysctl_check_leaf(namespaces, table, &fail);
+               }
+               if (table->mode > 0777)
+                       set_fail(&fail, table, "bogus .mode");
+               if (fail) {
+                       set_fail(&fail, table, NULL);
+                       error = -EINVAL;
+               }
+               if (table->child)
+                       error |= sysctl_check_table(namespaces, table->child);
+       }
+       return error;
+}
+#endif /* CONFIG_SYSCTL_SYSCALL_CHECK */
+
+/**
+ * __register_sysctl_table - register a leaf sysctl table
+ * @root: List of sysctl headers to register on
+ * @namespaces: Data to compute which lists of sysctl entries are visible
+ * @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_root *root,
+       struct nsproxy *namespaces,
+       const char *path, struct ctl_table *table)
+{
+       struct ctl_table_header *header;
+       struct ctl_table *new, **prevp;
+       const char *name, *nextname;
+       unsigned int npath = 0;
+       struct ctl_table_set *set;
+       size_t path_bytes = 0;
+       char *new_name;
+
+       /* Count the path components */
+       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;
+               path_bytes += namelen + 1;
+               npath++;
+       }
+
+       /*
+        * For each path component, allocate a 2-element ctl_table array.
+        * The first array element will be filled with the sysctl entry
+        * for this, the second will be the sentinel (procname == 0).
+        *
+        * We allocate everything in one go so that we don't have to
+        * worry about freeing additional memory in unregister_sysctl_table.
+        */
+       header = kzalloc(sizeof(struct ctl_table_header) + path_bytes +
+                        (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
+       if (!header)
+               return NULL;
+
+       new = (struct ctl_table *) (header + 1);
+       new_name = (char *)(new + (2 * npath));
+
+       /* Now connect the dots */
+       prevp = &header->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;
+               memcpy(new_name, name, namelen);
+               new_name[namelen] = '\0';
+
+               new->procname = new_name;
+               new->mode     = 0555;
+
+               *prevp = new;
+               prevp = &new->child;
+
+               new += 2;
+               new_name += namelen + 1;
+       }
+       *prevp = table;
+       header->ctl_table_arg = table;
+
+       INIT_LIST_HEAD(&header->ctl_entry);
+       header->used = 0;
+       header->unregistering = NULL;
+       header->root = root;
+       sysctl_set_parent(NULL, header->ctl_table);
+       header->count = 1;
+#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
+       if (sysctl_check_table(namespaces, header->ctl_table)) {
+               kfree(header);
+               return NULL;
+       }
+#endif
+       spin_lock(&sysctl_lock);
+       header->set = lookup_header_set(root, namespaces);
+       header->attached_by = header->ctl_table;
+       header->attached_to = root_table;
+       header->parent = &root_table_header;
+       set = header->set;
+       root = header->root;
+       for (;;) {
+               struct ctl_table_header *p;
+               list_for_each_entry(p, &set->list, ctl_entry) {
+                       if (p->unregistering)
+                               continue;
+                       try_attach(p, header);
+               }
+               if (root == &sysctl_table_root)
+                       break;
+               root = list_entry(root->root_list.prev,
+                                 struct ctl_table_root, root_list);
+               set = lookup_header_set(root, namespaces);
+       }
+       header->parent->count++;
+       list_add_tail(&header->ctl_entry, &header->set->list);
+       spin_unlock(&sysctl_lock);
+
+       return header;
+}
+
+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_root *root, struct nsproxy *namespaces,
+       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(root, namespaces, 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,
+                                                 root, namespaces, 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
+ * @root: List of sysctl headers to register on
+ * @namespaces: Data to compute which lists of sysctl entries are visible
+ * @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_root *root,
+       struct nsproxy *namespaces,
+       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(root, namespaces, 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,
+                                               root, namespaces, 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, current->nsproxy,
+                                       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);
+
+/**
+ * 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);
+       start_unregistering(header);
+       if (!--header->parent->count) {
+               WARN_ON(1);
+               kfree_rcu(header->parent, rcu);
+       }
+       if (!--header->count)
+               kfree_rcu(header, rcu);
+       spin_unlock(&sysctl_lock);
+}
+EXPORT_SYMBOL(unregister_sysctl_table);
+
+void setup_sysctl_set(struct ctl_table_set *p,
+       int (*is_seen)(struct ctl_table_set *))
+{
+       INIT_LIST_HEAD(&p->list);
+       p->is_seen = is_seen;
+}
+
+void retire_sysctl_set(struct ctl_table_set *set)
+{
+       WARN_ON(!list_empty(&set->list));
+}
+
 int __init proc_sys_init(void)
 {
        struct proc_dir_entry *proc_sys_root;
@@ -478,5 +1315,6 @@ int __init proc_sys_init(void)
        proc_sys_root->proc_iops = &proc_sys_dir_operations;
        proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
        proc_sys_root->nlink = 0;
-       return 0;
+
+       return sysctl_init();
 }