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* [PATCH] Code style fix for open_exec
@ 2007-10-04  2:40 Casey Dahlin
  2007-10-04  7:08 ` Christoph Hellwig
  0 siblings, 1 reply; 3+ messages in thread
From: Casey Dahlin @ 2007-10-04  2:40 UTC (permalink / raw)
  To: linux-kernel

 From d2a6c5d29dc34cfea892124ab72b4eb55d2f8a80 Mon Sep 17 00:00:00 2001
From: Casey Dahlin <cjdahlin@ncsu.edu>
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 <cjdahlin@ncsu.edu>

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);

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] Code style fix for open_exec
  2007-10-04  2:40 [PATCH] Code style fix for open_exec Casey Dahlin
@ 2007-10-04  7:08 ` Christoph Hellwig
  2007-10-04 17:35   ` Casey Dahlin
  0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2007-10-04  7:08 UTC (permalink / raw)
  To: Casey Dahlin; +Cc: linux-kernel

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 <cjdahlin@ncsu.edu>
> 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,

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] Code style fix for open_exec
  2007-10-04  7:08 ` Christoph Hellwig
@ 2007-10-04 17:35   ` Casey Dahlin
  0 siblings, 0 replies; 3+ messages in thread
From: Casey Dahlin @ 2007-10-04 17:35 UTC (permalink / raw)
  To: Christoph Hellwig, Casey Dahlin, linux-kernel

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 <cjdahlin@ncsu.edu>
>> 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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>   


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-10-04 17:35 UTC | newest]

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2007-10-04  2:40 [PATCH] Code style fix for open_exec Casey Dahlin
2007-10-04  7:08 ` Christoph Hellwig
2007-10-04 17:35   ` Casey Dahlin

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