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sysctl: Add size to register_net_sysctl function 

This commit adds size to the register_net_sysctl indirection function to
facilitate the removal of the sentinel elements (last empty markers)
from the ctl_table arrays. Though we don't actually remove any sentinels
in this commit, register_net_sysctl* now has the capability of
forwarding table_size for when that happens.

We create a new function register_net_sysctl_sz with an extra size
argument. A macro replaces the existing register_net_sysctl. The size in
the macro is SIZE_MAX instead of ARRAY_SIZE to avoid compilation errors
while we systematically migrate to register_net_sysctl_sz. Will change
to ARRAY_SIZE in subsequent commits.

Care is taken to add table_size to the stopping criteria in such a way
that when we remove the empty sentinel element, it will continue
stopping in the last element of the ctl_table array.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
Joel Granados 2023-08-09 12:50:00 +02:00 committed by Luis Chamberlain
parent 3bc269cfd3
commit 95d4977876
2 changed files with 19 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/net/net_namespace.h
View File

@ -469,15 +469,17 @@ void unregister_pernet_device(struct pernet_operations *);
struct ctl_table;
#define register_net_sysctl(net, path, table) \
register_net_sysctl_sz(net, path, table, SIZE_MAX)
#ifdef CONFIG_SYSCTL
int net_sysctl_init(void);
struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
struct ctl_table *table);
struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,
struct ctl_table *table, size_t table_size);
void unregister_net_sysctl_table(struct ctl_table_header *header);
#else
static inline int net_sysctl_init(void) { return 0; }
static inline struct ctl_table_header *register_net_sysctl(struct net *net,
const char *path, struct ctl_table *table)
static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,
const char *path, struct ctl_table *table, size_t table_size)
{
return NULL;
}

22
net/sysctl_net.c
View File

@ -122,12 +122,13 @@ out1:
* allocated.
*/
static void ensure_safe_net_sysctl(struct net *net, const char *path,
struct ctl_table *table)
struct ctl_table *table, size_t table_size)
{
struct ctl_table *ent;
pr_debug("Registering net sysctl (net %p): %s\n", net, path);
for (ent = table; ent->procname; ent++) {
ent = table;
for (size_t i = 0; i < table_size && ent->procname; ent++, i++) {
unsigned long addr;
const char *where;
@ -160,21 +161,24 @@ static void ensure_safe_net_sysctl(struct net *net, const char *path,
}
}
struct ctl_table_header *register_net_sysctl(struct net *net,
const char *path, struct ctl_table *table)
struct ctl_table_header *register_net_sysctl_sz(struct net *net,
const char *path,
struct ctl_table *table,
size_t table_size)
{
int count = 0;
int count;
struct ctl_table *entry;
if (!net_eq(net, &init_net))
ensure_safe_net_sysctl(net, path, table);
ensure_safe_net_sysctl(net, path, table, table_size);
for (entry = table; entry->procname; entry++)
count++;
entry = table;
for (count = 0 ; count < table_size && entry->procname; entry++, count++)
;
return __register_sysctl_table(&net->sysctls, path, table, count);
}
EXPORT_SYMBOL_GPL(register_net_sysctl);
EXPORT_SYMBOL_GPL(register_net_sysctl_sz);
void unregister_net_sysctl_table(struct ctl_table_header *header)
{