Commit 6e9d5164 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

sysctl: Add support for register sysctl tables with a normal cstring path. 



Make __register_sysctl_table the core sysctl registration operation and
make it take a char * string as path.

Now that binary paths have been banished into the real of backwards
compatibility in kernel/binary_sysctl.c where they can be safely
ignored there is no longer a need to use struct ctl_path to represent
path names when registering ctl_tables.

Start the transition to using normal char * strings to represent
pathnames when registering sysctl tables.  Normal strings are easier
to deal with both in the internal sysctl implementation and for
programmers registering sysctl tables.

__register_sysctl_paths is turned into a backwards compatibility wrapper
that converts a ctl_path array into a normal char * string.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent f05e53a7

fs/proc/proc_sysctl.c

+84 −10
Original line number Diff line number Diff line
@@ -882,7 +882,7 @@ static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *tabl 
#endif /* CONFIG_SYSCTL_SYSCALL_CHECK */



/**

 * __register_sysctl_paths - register a sysctl hierarchy

 * __register_sysctl_table - register a 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.
@@ -934,21 +934,34 @@ static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *tabl 
 * 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_header *__register_sysctl_table(

	struct ctl_table_root *root,

	struct nsproxy *namespaces,

	const struct ctl_path *path, struct ctl_table *table)

	const char *path, struct ctl_table *table)

{

	struct ctl_table_header *header;

	struct ctl_table *new, **prevp;

	unsigned int n, npath;

	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 (npath = 0; path[npath].procname; ++npath)

		path_bytes += strlen(path[npath].procname) + 1;

	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.
@@ -968,9 +981,20 @@ struct ctl_table_header *__register_sysctl_paths( 


	/* Now connect the dots */

	prevp = &header->ctl_table;

	for (n = 0; n < npath; ++n, ++path) {

		/* Copy the procname */

		strcpy(new_name, path->procname);

	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;
@@ -978,7 +1002,7 @@ struct ctl_table_header *__register_sysctl_paths( 
		prevp = &new->child;



		new += 2;

		new_name += strlen(new_name) + 1;

		new_name += namelen + 1;

	}

	*prevp = table;

	header->ctl_table_arg = table;
@@ -1022,6 +1046,56 @@ struct ctl_table_header *__register_sysctl_paths( 
	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;

}



/**

 * __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_header *header = NULL;

	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;

	}

	header = __register_sysctl_table(root, namespaces, new_path, table);

out:

	kfree(new_path);

	return header;

}



/**

 * register_sysctl_table_path - register a sysctl table hierarchy

 * @path: The path to the directory the sysctl table is in.

include/linux/sysctl.h

+3 −0
Original line number Diff line number Diff line
@@ -1073,6 +1073,9 @@ extern void setup_sysctl_set(struct ctl_table_set *p, 
extern void retire_sysctl_set(struct ctl_table_set *set);



void register_sysctl_root(struct ctl_table_root *root);

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 *__register_sysctl_paths(

	struct ctl_table_root *root, struct nsproxy *namespaces,

	const struct ctl_path *path, struct ctl_table *table);

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