A fairly trivial patch that simply improves the readability of the
open_exec() function. It no longer executes primarily inside nested ifs
or has 5 levels of indentation :) Logically it should be no different
from the original. Patch applies to stock 2.6.18 kernel.
Signed-off-by: Casey Dahlin <[email protected]>
---
diff -up exec.c.bak exec.c
--- exec.c.bak 2006-09-19 23:42:06.000000000 -0400
+++ exec.c 2006-10-12 21:42:01.000000000 -0400
@@ -474,36 +474,43 @@ static inline void free_arg_pages(struct
struct file *open_exec(const char *name)
{
struct nameidata nd;
- int err;
+ struct inode *inode;
+ int err, perm_err;
struct file *file;
err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|
FMODE_EXEC);
file = ERR_PTR(err);
- if (!err) {
- struct inode *inode = nd.dentry->d_inode;
- file = ERR_PTR(-EACCES);
- if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
- S_ISREG(inode->i_mode)) {
- int err = vfs_permission(&nd, MAY_EXEC);
- file = ERR_PTR(err);
- if (!err) {
- file = nameidata_to_filp(&nd, O_RDONLY);
- if (!IS_ERR(file)) {
- err = deny_write_access(file);
- if (err) {
- fput(file);
- file = ERR_PTR(err);
- }
- }
-out:
- return file;
- }
- }
- release_open_intent(&nd);
- path_release(&nd);
- }
+ if (err)
+ goto out;
+
+ inode = nd.dentry->d_inode;
+ file = ERR_PTR(-EACCES);
+ if ((nd.mnt->mnt_flags & MNT_NOEXEC) ||
+ !S_ISREG(inode->i_mode))
+ goto cleanup;
+
+ perm_err = vfs_permission(&nd, MAY_EXEC);
+ file = ERR_PTR(perm_err);
+ if (perm_err)
+ goto cleanup;
+
+ file = nameidata_to_filp(&nd, O_RDONLY);
+ if (IS_ERR(file))
+ goto out;
+
+ perm_err = deny_write_access(file);
+ if (perm_err) {
+ fput(file);
+ file = ERR_PTR(err);
+ }
goto out;
+
+cleanup:
+ release_open_intent(&nd);
+ path_release(&nd);
+out:
+ return file;
}
EXPORT_SYMBOL(open_exec);
-
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