diff options
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 502 | 
1 files changed, 4 insertions, 498 deletions
| diff --git a/kernel/sysctl.c b/kernel/sysctl.c index f487f257e05e..d48ff4fd44c3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -58,6 +58,7 @@  #include <linux/oom.h>  #include <linux/kmod.h>  #include <linux/capability.h> +#include <linux/binfmts.h>  #include <asm/uaccess.h>  #include <asm/processor.h> @@ -192,20 +193,6 @@ static int sysrq_sysctl_handler(ctl_table *table, int write,  #endif -static struct ctl_table root_table[]; -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 struct ctl_table kern_table[];  static struct ctl_table vm_table[];  static struct ctl_table fs_table[]; @@ -222,7 +209,7 @@ int sysctl_legacy_va_layout;  /* The default sysctl tables: */ -static struct ctl_table root_table[] = { +static struct ctl_table sysctl_base_table[] = {  	{  		.procname	= "kernel",  		.mode		= 0555, @@ -1559,490 +1546,12 @@ static struct ctl_table dev_table[] = {  	{ }  }; -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); -} - -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); -} - -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; -} - -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; -} - -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; -} - -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; -} - -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 __init int sysctl_init(void) +int __init sysctl_init(void)  { -	sysctl_set_parent(NULL, root_table); -#ifdef CONFIG_SYSCTL_SYSCALL_CHECK -	sysctl_check_table(current->nsproxy, root_table); -#endif +	register_sysctl_table(sysctl_base_table);  	return 0;  } -core_initcall(sysctl_init); - -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; -	} -} - -/** - * __register_sysctl_paths - register a sysctl 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. - * - * 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, and for sysctl(2) - * - * child - a pointer to the child sysctl table if this entry is a directory, or - *         %NULL. - * - * proc_handler - the text handler routine (described below) - * - * de - for internal use by the sysctl routines - * - * 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. - * - * sysctl(2) can automatically manage read and write requests through - * the sysctl table.  The data and maxlen fields of the ctl_table - * struct enable minimal validation of the values being written to be - * performed, and the mode field allows minimal authentication. - * - * There must be a proc_handler routine for any terminal nodes - * mirrored under /proc/sys (non-terminals are handled by a built-in - * directory handler).  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_paths( -	struct ctl_table_root *root, -	struct nsproxy *namespaces, -	const struct ctl_path *path, struct ctl_table *table) -{ -	struct ctl_table_header *header; -	struct ctl_table *new, **prevp; -	unsigned int n, npath; -	struct ctl_table_set *set; - -	/* Count the path components */ -	for (npath = 0; path[npath].procname; ++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) + -			 (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 */  /* @@ -3008,6 +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); | 
