Re: [apparmor] [PATCH 02/11] proc_sysctl: move helper which creates required subdirectories

[John Johansen]

On 3/2/23 12:28, Luis Chamberlain wrote:

Move the code which creates the subdirectories for a ctl table
into a helper routine so to make it easier to review. Document
the goal.

This creates no functional changes.

Signed-off-by: Luis Chamberlain <mcg...@kernel.org>

Reviewed-by: John Johansen <john.johan...@canonical.com>

---
  fs/proc/proc_sysctl.c | 56 ++++++++++++++++++++++++-------------------
  1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 1df0beb50dbe..6b9b2694d430 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1283,6 +1283,35 @@ static int insert_links(struct ctl_table_header *head)
        return err;
  }

+/* Find the directory for the ctl_table. If one is not found create it. */

+static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
+{
+       const char *name, *nextname;
+
+       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;
+
+               /*
+                * namelen ensures if name is "foo/bar/yay" only foo is
+                * registered first. We traverse as if using mkdir -p and
+                * return a ctl_dir for the last directory entry.
+                */
+               dir = get_subdir(dir, name, namelen);
+               if (IS_ERR(dir))
+                       break;
+       }
+       return dir;
+}
+
  /**
   * __register_sysctl_table - register a leaf sysctl table
   * @set: Sysctl tree to register on
@@ -1334,7 +1363,6 @@ struct ctl_table_header *__register_sysctl_table(
  {
        struct ctl_table_root *root = set->dir.header.root;
        struct ctl_table_header *header;
-       const char *name, *nextname;
        struct ctl_dir *dir;
        struct ctl_table *entry;
        struct ctl_node *node;
@@ -1359,29 +1387,9 @@ struct ctl_table_header *__register_sysctl_table(
        dir->header.nreg++;
        spin_unlock(&sysctl_lock);

- /* Find the directory for the ctl_table */

-       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;
-
-               /*
-                * namelen ensures if name is "foo/bar/yay" only foo is
-                * registered first. We traverse as if using mkdir -p and
-                * return a ctl_dir for the last directory entry.
-                */
-               dir = get_subdir(dir, name, namelen);
-               if (IS_ERR(dir))
-                       goto fail;
-       }
-
+       dir = sysctl_mkdir_p(dir, path);
+       if (IS_ERR(dir))
+               goto fail;
        spin_lock(&sysctl_lock);
        if (insert_header(dir, header))
                goto fail_put_dir_locked;