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Date: Thu, 26 Jan 2012 20:51:45 -0800
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: <linux-kernel@...r.kernel.org>
Cc: <linux-fsdevel@...r.kernel.org>, <netdev@...r.kernel.org>,
Lucian Adrian Grijincu <lucian.grijincu@...il.com>,
Damien Millescamps <damien.millescamps@...nd.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 09/29] 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: Eric W. Biederman <ebiederm@...ssion.com>
---
fs/proc/proc_sysctl.c | 94 ++++++++++++++++++++++++++++++++++++++++++-----
include/linux/sysctl.h | 3 ++
2 files changed, 87 insertions(+), 10 deletions(-)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index bcf60fb..5704ff0 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -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.
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 43c36ac..a514e0f 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -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);
--
1.7.2.5
--
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