[PATCH v2] wic: if we can't get from ioctl, try from os.stat()

[PATCH v2] wic: if we can't get from ioctl, try from os.stat()

[Dogukan Ergun]

Under some conditions, ioctl FIGETBSZ can't return real value.
We can try to use fallback via os.stat() to get block size.

Source of patch:
https://github.com/intel/bmap-tools/commit/17365f4fe9089df7ee9800a2a0ced177ec4798a4

Signed-off-by: Dogukan Ergun <dogukan.ergun@gmail.com>
---
 scripts/lib/wic/filemap.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py
index 77e32b9..a72fa09 100644
--- a/scripts/lib/wic/filemap.py
+++ b/scripts/lib/wic/filemap.py
@@ -37,7 +37,15 @@ def get_block_size(file_obj):
     # Get the block size of the host file-system for the image file by calling
     # the FIGETBSZ ioctl (number 2).
     binary_data = fcntl.ioctl(file_obj, 2, struct.pack('I', 0))
-    return struct.unpack('I', binary_data)[0]
+    bsize = struct.unpack('I', binary_data)[0]
+    if not bsize:
+        import os
+        stat = os.fstat(file_obj.fileno())
+        if hasattr(stat, 'st_blksize'):
+            bsize = stat.st_blksize
+        else:
+            raise IOError("Unable to determine block size")
+    return bsize
 
 class ErrorNotSupp(Exception):
     """
-- 
2.7.4

Re: [PATCH v2] wic: if we can't get from ioctl, try from os.stat()

[Ed Bartosh]

On Tue, Jan 09, 2018 at 04:35:24PM +0300, Dogukan Ergun wrote:
> Under some conditions, ioctl FIGETBSZ can't return real value.
> We can try to use fallback via os.stat() to get block size.
> 

Thank you for the patch!

+1


> Source of patch:
> https://github.com/intel/bmap-tools/commit/17365f4fe9089df7ee9800a2a0ced177ec4798a4
> 
> Signed-off-by: Dogukan Ergun <dogukan.ergun@gmail.com>
> ---
>  scripts/lib/wic/filemap.py | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py
> index 77e32b9..a72fa09 100644
> --- a/scripts/lib/wic/filemap.py
> +++ b/scripts/lib/wic/filemap.py
> @@ -37,7 +37,15 @@ def get_block_size(file_obj):
>      # Get the block size of the host file-system for the image file by calling
>      # the FIGETBSZ ioctl (number 2).
>      binary_data = fcntl.ioctl(file_obj, 2, struct.pack('I', 0))
> -    return struct.unpack('I', binary_data)[0]
> +    bsize = struct.unpack('I', binary_data)[0]
> +    if not bsize:
> +        import os
> +        stat = os.fstat(file_obj.fileno())
> +        if hasattr(stat, 'st_blksize'):
> +            bsize = stat.st_blksize
> +        else:
> +            raise IOError("Unable to determine block size")
> +    return bsize
>  
>  class ErrorNotSupp(Exception):
>      """
> -- 
> 2.7.4
> 
> -- 
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> Openembedded-core mailing list
> Openembedded-core@lists.openembedded.org
> http://lists.openembedded.org/mailman/listinfo/openembedded-core

-- 
--
Regards,
Ed