From d2a6c5d29dc34cfea892124ab72b4eb55d2f8a80 Mon Sep 17 00:00:00 2001
From: Casey Dahlin <[email protected]>
Date: Wed, 3 Oct 2007 22:01:49 -0400
Subject: [PATCH] Code style fix for open_exec
Fix a horribly mangled 5 level indent and severe abuse of goto in the
open_exec
function.
Signed-off-by: Casey Dahlin <[email protected]>
diff --git a/fs/exec.c b/fs/exec.c
index c21a8cc..d73da5a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -676,32 +676,32 @@ struct file *open_exec(const char *name)
struct file *file;
err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
FMODE_READ|FMODE_EXEC);
+
+ if (err) return ERR_PTR(err);
+
+ file = ERR_PTR(-EACCES);
+ if ((nd.mnt->mnt_flags & MNT_NOEXEC) ||
+ !S_ISREG(nd.dentry->d_inode->i_mode))
+ goto fail;
+
+ err = vfs_permission(&nd, MAY_EXEC);
file = ERR_PTR(err);
+ if (err) goto fail;
- 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);
+ file = nameidata_to_filp(&nd, O_RDONLY);
+ if (IS_ERR(file)) return file;
+
+ err = deny_write_access(file);
+ if (err) {
+ fput(file);
+ file = ERR_PTR(err);
}
- goto out;
+
+ return file;
+fail:
+ release_open_intent(&nd);
+ path_release(&nd);
+ return file;
}
EXPORT_SYMBOL(open_exec);
On Wed, Oct 03, 2007 at 10:40:25PM -0400, Casey Dahlin wrote:
> From d2a6c5d29dc34cfea892124ab72b4eb55d2f8a80 Mon Sep 17 00:00:00 2001
> From: Casey Dahlin <[email protected]>
> Date: Wed, 3 Oct 2007 22:01:49 -0400
> Subject: [PATCH] Code style fix for open_exec
>
> Fix a horribly mangled 5 level indent and severe abuse of goto in the
> open_exec
> function.
While the function is not nice your version makes it even worse.
Try this one instead which has been in my pending testing tree for a while:
Index: linux-2.6/fs/exec.c
===================================================================
--- linux-2.6.orig/fs/exec.c 2007-09-16 20:29:01.000000000 +0200
+++ linux-2.6/fs/exec.c 2007-09-16 20:29:56.000000000 +0200
@@ -669,41 +669,55 @@ EXPORT_SYMBOL(setup_arg_pages);
#endif /* CONFIG_MMU */
+/**
+ * open_exec - open file for execution
+ * @name: filename to open
+ *
+ * Open the file pointed to by @filename in the current namespace
+ * for execution. Error out if the file is not a regular file or
+ * this mount does not allow executing files on it.
+ */
struct file *open_exec(const char *name)
{
struct nameidata nd;
- int err;
struct file *file;
+ int err;
- err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
- file = ERR_PTR(err);
+ err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
+ FMODE_READ|FMODE_EXEC);
+ if (unlikely(err))
+ goto out;
- 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);
+ err = -EACCES;
+ if (unlikely(nd.mnt->mnt_flags & MNT_NOEXEC))
+ goto out_path_release;
+ if (unlikely(!S_ISREG(nd.dentry->d_inode->i_mode)))
+ goto out_path_release;
+
+ err = vfs_permission(&nd, MAY_EXEC);
+ if (unlikely(err))
+ goto out_path_release;
+
+ file = nameidata_to_filp(&nd, O_RDONLY);
+ if (unlikely(IS_ERR(file))) {
+ err = PTR_ERR(file);
+ goto out;
+ }
+
+ err = deny_write_access(file);
+ if (unlikely(err)) {
+ fput(file);
+ goto out;
}
- goto out;
-}
+ return file;
+
+ out_path_release:
+ release_open_intent(&nd);
+ path_release(&nd);
+ out:
+ return ERR_PTR(err);
+}
EXPORT_SYMBOL(open_exec);
int kernel_read(struct file *file, unsigned long offset,
Christoph Hellwig wrote:
> On Wed, Oct 03, 2007 at 10:40:25PM -0400, Casey Dahlin wrote:
>
>> From d2a6c5d29dc34cfea892124ab72b4eb55d2f8a80 Mon Sep 17 00:00:00 2001
>> From: Casey Dahlin <[email protected]>
>> Date: Wed, 3 Oct 2007 22:01:49 -0400
>> Subject: [PATCH] Code style fix for open_exec
>>
>> Fix a horribly mangled 5 level indent and severe abuse of goto in the
>> open_exec
>> function.
>>
>
> While the function is not nice your version makes it even worse.
>
Ouch :) I don't think I did so bad.
> Try this one instead which has been in my pending testing tree for a while:
>
Pretty much all of the stylistic changes were recommended to me already
off list by Joe Perches. I have that in my branch now, and was waiting
on any further feedback before resubmitting. There's a couple of things
here though (particularly the unlikelys) that are worth having. This is
the better code.
>
>
> Index: linux-2.6/fs/exec.c
> ===================================================================
> --- linux-2.6.orig/fs/exec.c 2007-09-16 20:29:01.000000000 +0200
> +++ linux-2.6/fs/exec.c 2007-09-16 20:29:56.000000000 +0200
> @@ -669,41 +669,55 @@ EXPORT_SYMBOL(setup_arg_pages);
>
> #endif /* CONFIG_MMU */
>
> +/**
> + * open_exec - open file for execution
> + * @name: filename to open
> + *
> + * Open the file pointed to by @filename in the current namespace
> + * for execution. Error out if the file is not a regular file or
> + * this mount does not allow executing files on it.
> + */
> struct file *open_exec(const char *name)
> {
> struct nameidata nd;
> - int err;
> struct file *file;
> + int err;
>
> - err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
> - file = ERR_PTR(err);
> + err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
> + FMODE_READ|FMODE_EXEC);
> + if (unlikely(err))
> + goto out;
>
> - 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);
> + err = -EACCES;
> + if (unlikely(nd.mnt->mnt_flags & MNT_NOEXEC))
> + goto out_path_release;
> + if (unlikely(!S_ISREG(nd.dentry->d_inode->i_mode)))
> + goto out_path_release;
> +
> + err = vfs_permission(&nd, MAY_EXEC);
> + if (unlikely(err))
> + goto out_path_release;
> +
> + file = nameidata_to_filp(&nd, O_RDONLY);
> + if (unlikely(IS_ERR(file))) {
> + err = PTR_ERR(file);
> + goto out;
> + }
> +
> + err = deny_write_access(file);
> + if (unlikely(err)) {
> + fput(file);
> + goto out;
> }
> - goto out;
> -}
>
> + return file;
> +
> + out_path_release:
> + release_open_intent(&nd);
> + path_release(&nd);
> + out:
> + return ERR_PTR(err);
> +}
> EXPORT_SYMBOL(open_exec);
>
> int kernel_read(struct file *file, unsigned long offset,
> -
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