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Commit 8ce584c7 authored by Al Viro's avatar Al Viro
Browse files

procfs: add proc_remove_subtree() 



just what it sounds like; do that only to procfs subtrees you've
created - doing that to something shared with another driver is
not only antisocial, but might cause interesting races with
proc_create() and its ilk.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 52f21999

fs/proc/generic.c

+89 −30
Original line number Diff line number Diff line
@@ -755,37 +755,8 @@ void pde_put(struct proc_dir_entry *pde) 
		free_proc_entry(pde);

}



/*

 * Remove a /proc entry and free it if it's not currently in use.

 */

void remove_proc_entry(const char *name, struct proc_dir_entry *parent)

static void entry_rundown(struct proc_dir_entry *de)

{

	struct proc_dir_entry **p;

	struct proc_dir_entry *de = NULL;

	const char *fn = name;

	unsigned int len;



	spin_lock(&proc_subdir_lock);

	if (__xlate_proc_name(name, &parent, &fn) != 0) {

		spin_unlock(&proc_subdir_lock);

		return;

	}

	len = strlen(fn);



	for (p = &parent->subdir; *p; p=&(*p)->next ) {

		if (proc_match(len, fn, *p)) {

			de = *p;

			*p = de->next;

			de->next = NULL;

			break;

		}

	}

	spin_unlock(&proc_subdir_lock);

	if (!de) {

		WARN(1, "name '%s'\n", name);

		return;

	}



	spin_lock(&de->pde_unload_lock);

	/*

	 * Stop accepting new callers into module. If you're
@@ -817,6 +788,40 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 
		spin_lock(&de->pde_unload_lock);

	}

	spin_unlock(&de->pde_unload_lock);

}



/*

 * Remove a /proc entry and free it if it's not currently in use.

 */

void remove_proc_entry(const char *name, struct proc_dir_entry *parent)

{

	struct proc_dir_entry **p;

	struct proc_dir_entry *de = NULL;

	const char *fn = name;

	unsigned int len;



	spin_lock(&proc_subdir_lock);

	if (__xlate_proc_name(name, &parent, &fn) != 0) {

		spin_unlock(&proc_subdir_lock);

		return;

	}

	len = strlen(fn);



	for (p = &parent->subdir; *p; p=&(*p)->next ) {

		if (proc_match(len, fn, *p)) {

			de = *p;

			*p = de->next;

			de->next = NULL;

			break;

		}

	}

	spin_unlock(&proc_subdir_lock);

	if (!de) {

		WARN(1, "name '%s'\n", name);

		return;

	}



	entry_rundown(de);



	if (S_ISDIR(de->mode))

		parent->nlink--;
@@ -827,3 +832,57 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 
	pde_put(de);

}

EXPORT_SYMBOL(remove_proc_entry);



int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)

{

	struct proc_dir_entry **p;

	struct proc_dir_entry *root = NULL, *de, *next;

	const char *fn = name;

	unsigned int len;



	spin_lock(&proc_subdir_lock);

	if (__xlate_proc_name(name, &parent, &fn) != 0) {

		spin_unlock(&proc_subdir_lock);

		return -ENOENT;

	}

	len = strlen(fn);



	for (p = &parent->subdir; *p; p=&(*p)->next ) {

		if (proc_match(len, fn, *p)) {

			root = *p;

			*p = root->next;

			root->next = NULL;

			break;

		}

	}

	if (!root) {

		spin_unlock(&proc_subdir_lock);

		return -ENOENT;

	}

	de = root;

	while (1) {

		next = de->subdir;

		if (next) {

			de->subdir = next->next;

			next->next = NULL;

			de = next;

			continue;

		}

		spin_unlock(&proc_subdir_lock);



		entry_rundown(de);

		next = de->parent;

		if (S_ISDIR(de->mode))

			next->nlink--;

		de->nlink = 0;

		if (de == root)

			break;

		pde_put(de);



		spin_lock(&proc_subdir_lock);

		de = next;

	}

	pde_put(root);

	return 0;

}

EXPORT_SYMBOL(remove_proc_subtree);

include/linux/proc_fs.h

+2 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, 
				const struct file_operations *proc_fops,

				void *data);

extern void remove_proc_entry(const char *name, struct proc_dir_entry *parent);

extern int remove_proc_subtree(const char *name, struct proc_dir_entry *parent);



struct pid_namespace;
@@ -202,6 +203,7 @@ static inline struct proc_dir_entry *proc_create_data(const char *name, 
	return NULL;

}

#define remove_proc_entry(name, parent) do {} while (0)

#define remove_proc_subtree(name, parent) do {} while (0)



static inline struct proc_dir_entry *proc_symlink(const char *name,

		struct proc_dir_entry *parent,const char *dest) {return NULL;}