[PATCH 1/1] devfs: add symlink support

[Jean-Christophe PLAGNIOL-VILLARD]

ping
On 12:35 Sat 16 Feb     , Jean-Christophe PLAGNIOL-VILLARD wrote:
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> ---
>  fs/devfs.c       |   70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/driver.h |    1 +
>  2 files changed, 71 insertions(+)
> 
> diff --git a/fs/devfs.c b/fs/devfs.c
> index f089c6f..c0047e3 100644
> --- a/fs/devfs.c
> +++ b/fs/devfs.c
> @@ -216,6 +216,12 @@ static int devfs_stat(struct device_d *_dev, const char *filename, struct stat *
>  	if (!cdev)
>  		return -ENOENT;
>  
> +	if (cdev->symlink) {
> +		s->st_mode = S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
> +		s->st_size = strlen(cdev->symlink);
> +		return 0;
> +	}
> +
>  	s->st_mode = S_IFCHR;
>  	s->st_size = cdev->size;
>  	if (cdev->ops->write)
> @@ -235,7 +241,69 @@ static void devfs_delete(struct device_d *dev)
>  {
>  }
>  
> +static int devfs_symlink(struct device_d *dev, const char *pathname,
> +		       const char *newpath)
> +{
> +	struct cdev *cdev;
> +	int ret = -ENOMEM;
> +
> +	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
> +	if (!cdev)
> +		return -ENOMEM;
> +
> +	cdev->symlink = strdup(pathname);
> +	if (!cdev->symlink)
> +		goto err;
> +
> +	cdev->name = strdup(newpath + 1);
> +	if (!cdev->name)
> +		goto err_cdev;
> +
> +	ret = devfs_create(cdev);
> +	if (ret)
> +		goto err_create;
> +
> +	return 0;
> +
> +err_create:
> +	kfree(cdev->name);
> +err_cdev:
> +	kfree(cdev->symlink);
> +err:
> +	kfree(cdev);
> +	return ret;
> +}
> +
> +static int devfs_readlink(struct device_d *dev, const char *pathname,
> +			char *buf, size_t bufsiz)
> +{
> +	struct cdev *cdev;
> +	int len;
> +
> +	cdev = cdev_by_name(pathname + 1);
> +	if (!cdev || !cdev->symlink)
> +		return -ENOENT;
> +
> +	len = min(bufsiz, strlen(cdev->symlink));
> +
> +	memcpy(buf, cdev->symlink, len);
> +
> +	return 0;
> +}
> +
> +static int devfs_unlink(struct device_d *dev, const char *pathname)
> +{
> +	struct cdev *cdev;
> +
> +	cdev = cdev_by_name(pathname + 1);
> +	if (!cdev || !cdev->symlink)
> +		return -EPERM;
> +
> +	return devfs_remove(cdev);
> +}
> +
>  static struct fs_driver_d devfs_driver = {
> +	.unlink    = devfs_unlink,
>  	.read      = devfs_read,
>  	.write     = devfs_write,
>  	.lseek     = devfs_lseek,
> @@ -248,6 +316,8 @@ static struct fs_driver_d devfs_driver = {
>  	.truncate  = devfs_truncate,
>  	.closedir  = devfs_closedir,
>  	.stat      = devfs_stat,
> +	.symlink   = devfs_symlink,
> +	.readlink  = devfs_readlink,
>  	.erase     = devfs_erase,
>  	.protect   = devfs_protect,
>  	.memmap    = devfs_memmap,
> diff --git a/include/driver.h b/include/driver.h
> index 151829e..1b0e619 100644
> --- a/include/driver.h
> +++ b/include/driver.h
> @@ -432,6 +432,7 @@ struct cdev {
>  	loff_t size;
>  	unsigned int flags;
>  	int open;
> +	char *symlink;
>  	struct mtd_info *mtd;
>  };
>  
> -- 
> 1.7.10.4
>