mirror of
https://github.com/Fishwaldo/Star64_linux.git
synced 2025-06-19 13:11:14 +00:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl
Pull sysctl updates from Eric Biederman: - Rewrite of sysctl for speed and clarity. Insert/remove/Lookup in sysctl are all now O(NlogN) operations, and are no longer bottlenecks in the process of adding and removing network devices. sysctl is now focused on being a filesystem instead of system call and the code can all be found in fs/proc/proc_sysctl.c. Hopefully this means the code is now approachable. Much thanks is owed to Lucian Grinjincu for keeping at this until something was found that was usable. - The recent proc_sys_poll oops found by the fuzzer during hibernation is fixed. * git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl: (36 commits) sysctl: protect poll() in entries that may go away sysctl: Don't call sysctl_follow_link unless we are a link. sysctl: Comments to make the code clearer. sysctl: Correct error return from get_subdir sysctl: An easier to read version of find_subdir sysctl: fix memset parameters in setup_sysctl_set() sysctl: remove an unused variable sysctl: Add register_sysctl for normal sysctl users sysctl: Index sysctl directories with rbtrees. sysctl: Make the header lists per directory. sysctl: Move sysctl_check_dups into insert_header sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy sysctl: Replace root_list with links between sysctl_table_sets. sysctl: Add sysctl_print_dir and use it in get_subdir sysctl: Stop requiring explicit management of sysctl directories sysctl: Add a root pointer to ctl_table_set sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry. sysctl: Normalize the root_table data structure. sysctl: Factor out insert_header and erase_header ...
This commit is contained in:
Linus Torvalds
commit
f1d38e423a
8 changed files with 1280 additions and 797 deletions
501
kernel/sysctl.c
501
kernel/sysctl.c
|
|
@ -193,20 +193,6 @@ static int sysrq_sysctl_handler(ctl_table *table, int write,
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#endif
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static struct ctl_table root_table[];
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static struct ctl_table_root sysctl_table_root;
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static struct ctl_table_header root_table_header = {
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{{.count = 1,
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.ctl_table = root_table,
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.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
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.root = &sysctl_table_root,
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.set = &sysctl_table_root.default_set,
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};
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static struct ctl_table_root sysctl_table_root = {
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.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
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.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
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};
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static struct ctl_table kern_table[];
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static struct ctl_table vm_table[];
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static struct ctl_table fs_table[];
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@ -223,7 +209,7 @@ int sysctl_legacy_va_layout;
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/* The default sysctl tables: */
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static struct ctl_table root_table[] = {
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static struct ctl_table sysctl_base_table[] = {
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{
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.procname = "kernel",
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.mode = 0555,
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@ -1560,490 +1546,12 @@ static struct ctl_table dev_table[] = {
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{ }
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};
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static DEFINE_SPINLOCK(sysctl_lock);
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/* called under sysctl_lock */
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static int use_table(struct ctl_table_header *p)
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int __init sysctl_init(void)
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{
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if (unlikely(p->unregistering))
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return 0;
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p->used++;
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return 1;
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}
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/* called under sysctl_lock */
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static void unuse_table(struct ctl_table_header *p)
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{
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if (!--p->used)
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if (unlikely(p->unregistering))
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complete(p->unregistering);
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}
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/* called under sysctl_lock, will reacquire if has to wait */
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static void start_unregistering(struct ctl_table_header *p)
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{
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/*
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* if p->used is 0, nobody will ever touch that entry again;
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* we'll eliminate all paths to it before dropping sysctl_lock
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*/
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if (unlikely(p->used)) {
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struct completion wait;
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init_completion(&wait);
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p->unregistering = &wait;
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spin_unlock(&sysctl_lock);
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wait_for_completion(&wait);
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spin_lock(&sysctl_lock);
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} else {
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/* anything non-NULL; we'll never dereference it */
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p->unregistering = ERR_PTR(-EINVAL);
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}
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/*
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* do not remove from the list until nobody holds it; walking the
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* list in do_sysctl() relies on that.
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*/
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list_del_init(&p->ctl_entry);
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}
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void sysctl_head_get(struct ctl_table_header *head)
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{
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spin_lock(&sysctl_lock);
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head->count++;
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spin_unlock(&sysctl_lock);
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}
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void sysctl_head_put(struct ctl_table_header *head)
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{
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spin_lock(&sysctl_lock);
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if (!--head->count)
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kfree_rcu(head, rcu);
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spin_unlock(&sysctl_lock);
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}
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struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
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{
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if (!head)
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BUG();
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spin_lock(&sysctl_lock);
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if (!use_table(head))
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head = ERR_PTR(-ENOENT);
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spin_unlock(&sysctl_lock);
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return head;
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}
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void sysctl_head_finish(struct ctl_table_header *head)
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{
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if (!head)
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return;
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spin_lock(&sysctl_lock);
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unuse_table(head);
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spin_unlock(&sysctl_lock);
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}
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static struct ctl_table_set *
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lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
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{
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struct ctl_table_set *set = &root->default_set;
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if (root->lookup)
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set = root->lookup(root, namespaces);
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return set;
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}
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static struct list_head *
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lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
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{
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struct ctl_table_set *set = lookup_header_set(root, namespaces);
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return &set->list;
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}
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struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
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struct ctl_table_header *prev)
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{
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struct ctl_table_root *root;
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struct list_head *header_list;
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struct ctl_table_header *head;
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struct list_head *tmp;
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spin_lock(&sysctl_lock);
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if (prev) {
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head = prev;
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tmp = &prev->ctl_entry;
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unuse_table(prev);
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goto next;
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}
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tmp = &root_table_header.ctl_entry;
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for (;;) {
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head = list_entry(tmp, struct ctl_table_header, ctl_entry);
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if (!use_table(head))
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goto next;
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spin_unlock(&sysctl_lock);
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return head;
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next:
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root = head->root;
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tmp = tmp->next;
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header_list = lookup_header_list(root, namespaces);
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if (tmp != header_list)
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continue;
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do {
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root = list_entry(root->root_list.next,
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struct ctl_table_root, root_list);
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if (root == &sysctl_table_root)
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goto out;
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header_list = lookup_header_list(root, namespaces);
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} while (list_empty(header_list));
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tmp = header_list->next;
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}
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out:
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spin_unlock(&sysctl_lock);
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return NULL;
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}
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struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
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{
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return __sysctl_head_next(current->nsproxy, prev);
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}
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void register_sysctl_root(struct ctl_table_root *root)
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{
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spin_lock(&sysctl_lock);
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list_add_tail(&root->root_list, &sysctl_table_root.root_list);
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spin_unlock(&sysctl_lock);
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}
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/*
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* sysctl_perm does NOT grant the superuser all rights automatically, because
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* some sysctl variables are readonly even to root.
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*/
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static int test_perm(int mode, int op)
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{
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if (!current_euid())
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mode >>= 6;
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else if (in_egroup_p(0))
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mode >>= 3;
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if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
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return 0;
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return -EACCES;
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}
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int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
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{
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int mode;
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if (root->permissions)
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mode = root->permissions(root, current->nsproxy, table);
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else
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mode = table->mode;
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return test_perm(mode, op);
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}
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static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
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{
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for (; table->procname; table++) {
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table->parent = parent;
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if (table->child)
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sysctl_set_parent(table, table->child);
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}
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}
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static __init int sysctl_init(void)
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{
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sysctl_set_parent(NULL, root_table);
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#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
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sysctl_check_table(current->nsproxy, root_table);
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#endif
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register_sysctl_table(sysctl_base_table);
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return 0;
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}
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core_initcall(sysctl_init);
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static struct ctl_table *is_branch_in(struct ctl_table *branch,
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struct ctl_table *table)
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{
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struct ctl_table *p;
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const char *s = branch->procname;
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/* branch should have named subdirectory as its first element */
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if (!s || !branch->child)
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return NULL;
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/* ... and nothing else */
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if (branch[1].procname)
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return NULL;
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/* table should contain subdirectory with the same name */
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for (p = table; p->procname; p++) {
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if (!p->child)
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continue;
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if (p->procname && strcmp(p->procname, s) == 0)
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return p;
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}
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return NULL;
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}
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/* see if attaching q to p would be an improvement */
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static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
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{
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struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
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struct ctl_table *next;
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int is_better = 0;
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int not_in_parent = !p->attached_by;
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while ((next = is_branch_in(by, to)) != NULL) {
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if (by == q->attached_by)
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is_better = 1;
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if (to == p->attached_by)
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not_in_parent = 1;
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by = by->child;
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to = next->child;
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}
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if (is_better && not_in_parent) {
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q->attached_by = by;
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q->attached_to = to;
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q->parent = p;
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}
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}
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/**
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* __register_sysctl_paths - register a sysctl hierarchy
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* @root: List of sysctl headers to register on
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* @namespaces: Data to compute which lists of sysctl entries are visible
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* @path: The path to the directory the sysctl table is in.
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* @table: the top-level table structure
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*
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* Register a sysctl table hierarchy. @table should be a filled in ctl_table
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* array. A completely 0 filled entry terminates the table.
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*
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* The members of the &struct ctl_table structure are used as follows:
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*
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* procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
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* enter a sysctl file
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*
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* data - a pointer to data for use by proc_handler
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*
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* maxlen - the maximum size in bytes of the data
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*
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* mode - the file permissions for the /proc/sys file, and for sysctl(2)
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*
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* child - a pointer to the child sysctl table if this entry is a directory, or
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* %NULL.
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*
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* proc_handler - the text handler routine (described below)
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*
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* de - for internal use by the sysctl routines
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*
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* extra1, extra2 - extra pointers usable by the proc handler routines
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*
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* Leaf nodes in the sysctl tree will be represented by a single file
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* under /proc; non-leaf nodes will be represented by directories.
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*
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* sysctl(2) can automatically manage read and write requests through
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* the sysctl table. The data and maxlen fields of the ctl_table
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* struct enable minimal validation of the values being written to be
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* performed, and the mode field allows minimal authentication.
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*
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* There must be a proc_handler routine for any terminal nodes
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* mirrored under /proc/sys (non-terminals are handled by a built-in
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* directory handler). Several default handlers are available to
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* cover common cases -
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*
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* proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
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* proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
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* proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
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*
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* It is the handler's job to read the input buffer from user memory
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* and process it. The handler should return 0 on success.
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*
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||||
* This routine returns %NULL on a failure to register, and a pointer
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* to the table header on success.
|
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*/
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struct ctl_table_header *__register_sysctl_paths(
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struct ctl_table_root *root,
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struct nsproxy *namespaces,
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||||
const struct ctl_path *path, struct ctl_table *table)
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||||
{
|
||||
struct ctl_table_header *header;
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||||
struct ctl_table *new, **prevp;
|
||||
unsigned int n, npath;
|
||||
struct ctl_table_set *set;
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||||
|
||||
/* Count the path components */
|
||||
for (npath = 0; path[npath].procname; ++npath)
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||||
;
|
||||
|
||||
/*
|
||||
* 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) +
|
||||
(2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
|
||||
if (!header)
|
||||
return NULL;
|
||||
|
||||
new = (struct ctl_table *) (header + 1);
|
||||
|
||||
/* Now connect the dots */
|
||||
prevp = &header->ctl_table;
|
||||
for (n = 0; n < npath; ++n, ++path) {
|
||||
/* Copy the procname */
|
||||
new->procname = path->procname;
|
||||
new->mode = 0555;
|
||||
|
||||
*prevp = new;
|
||||
prevp = &new->child;
|
||||
|
||||
new += 2;
|
||||
}
|
||||
*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;
|
||||
for (set = header->set; set; set = set->parent) {
|
||||
struct ctl_table_header *p;
|
||||
list_for_each_entry(p, &set->list, ctl_entry) {
|
||||
if (p->unregistering)
|
||||
continue;
|
||||
try_attach(p, header);
|
||||
}
|
||||
}
|
||||
header->parent->count++;
|
||||
list_add_tail(&header->ctl_entry, &header->set->list);
|
||||
spin_unlock(&sysctl_lock);
|
||||
|
||||
return header;
|
||||
}
|
||||
|
||||
/**
|
||||
* 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);
|
||||
}
|
||||
|
||||
/**
|
||||
* 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);
|
||||
}
|
||||
|
||||
/**
|
||||
* 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)
|
||||
{
|
||||
might_sleep();
|
||||
|
||||
if (header == NULL)
|
||||
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);
|
||||
}
|
||||
|
||||
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;
|
||||
}
|
||||
|
||||
void setup_sysctl_set(struct ctl_table_set *p,
|
||||
struct ctl_table_set *parent,
|
||||
int (*is_seen)(struct ctl_table_set *))
|
||||
{
|
||||
INIT_LIST_HEAD(&p->list);
|
||||
p->parent = parent ? parent : &sysctl_table_root.default_set;
|
||||
p->is_seen = is_seen;
|
||||
}
|
||||
|
||||
#else /* !CONFIG_SYSCTL */
|
||||
struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
|
||||
struct ctl_table *table)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
void unregister_sysctl_table(struct ctl_table_header * table)
|
||||
{
|
||||
}
|
||||
|
||||
void setup_sysctl_set(struct ctl_table_set *p,
|
||||
struct ctl_table_set *parent,
|
||||
int (*is_seen)(struct ctl_table_set *))
|
||||
{
|
||||
}
|
||||
|
||||
void sysctl_head_put(struct ctl_table_header *head)
|
||||
{
|
||||
}
|
||||
|
||||
#endif /* CONFIG_SYSCTL */
|
||||
|
||||
/*
|
||||
|
|
@ -3009,6 +2517,3 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
|
|||
EXPORT_SYMBOL(proc_dostring);
|
||||
EXPORT_SYMBOL(proc_doulongvec_minmax);
|
||||
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
|
||||
EXPORT_SYMBOL(register_sysctl_table);
|
||||
EXPORT_SYMBOL(register_sysctl_paths);
|
||||
EXPORT_SYMBOL(unregister_sysctl_table);
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue