[Buildroot] [git commit] support/testing/infra: add img_round_power2() function
Yann E. MORIN
yann.morin.1998 at free.fr
Sat Jun 26 19:27:48 UTC 2021
commit: https://git.buildroot.net/buildroot/commit/?id=37a1af7a74e57e42ff6beefb8a7fdcae01a00ff7
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
Since Qemu 5.1, SD card images must have a size that are a power of
two. While some filesystem (such as ext2/3/4) allow to specify the
expected size of the filesystem, others such as SquashFS do not have
this capability.
We were already extending the size of such images to the next 1 MB
boundary using "truncate -s %1M", but that is no longer sufficient. So
instead, we introduce a helper function that extends the size of an
image to the next power of two.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
[yann.morin.1998 at free.fr:
- use f.trunctate() rather than subprocess.call([truncate,...])
]
Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
---
support/testing/infra/__init__.py | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/support/testing/infra/__init__.py b/support/testing/infra/__init__.py
index 6522a265f3..b10a7601a3 100644
--- a/support/testing/infra/__init__.py
+++ b/support/testing/infra/__init__.py
@@ -112,3 +112,15 @@ def get_elf_prog_interpreter(builddir, prefix, fpath):
continue
return m.group(1)
return None
+
+
+def img_round_power2(img):
+ """
+ Rounds up the size of an image file to the next power of 2
+ """
+ sz = os.stat(img).st_size
+ pow2 = 1
+ while pow2 < sz:
+ pow2 = pow2 << 1
+ with open(img, 'ab') as f:
+ f.truncate(pow2)
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