[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <47052458.2090600@ncsu.edu>
Date: Thu, 04 Oct 2007 13:35:20 -0400
From: Casey Dahlin <cjdahlin@...u.edu>
To: Christoph Hellwig <hch@...radead.org>,
Casey Dahlin <cjdahlin@...u.edu>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Code style fix for open_exec
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@...u.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,
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists