[PATCH] erofs-utils: lib: simplify s3erofs_prepare_url logic

[Gao Xiang]

On 2025/9/30 17:25, zhaoyifan (H) wrote:
> 
> On 2025/9/30 17:06, Gao Xiang wrote:
>> Hi Yifan,
>>
>> On 2025/9/30 16:40, Yifan Zhao wrote:
>>> From: zhaoyifan <zhaoyifan28 at huawei.com>
>>>
>>> `mkfs.erofs` failed to generate image from Huawei OBS with the following command:
>>>
>>>     mkfs.erofs --s3=<endpoint>,urlstyle=vhost,sig=2 s3.erofs test-bucket
>>>
>>> because it mistakenly generated a url with repeated '/':
>>>
>>> https://test-bucket.<endpoint>//<keyname>
>>>
>>> In fact, the splitting of bucket name and path has already been performed prior
>>> to the call to `s3erofs_prepare_url`, and this function does not need to handle
>>> this logic. This patch simplifies this part accordingly and fixes the problem.
>>>
>>> Fixes: 29728ba8f6f6 ("erofs-utils: mkfs: support EROFS meta-only image generation from S3")
>>> Signed-off-by: Yifan Zhao <zhaoyifan28 at huawei.com>
>>> ---
>>>   lib/remotes/s3.c | 35 ++++++++++-------------------------
>>>   1 file changed, 10 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/lib/remotes/s3.c b/lib/remotes/s3.c
>>> index 2e7763e..2bd5322 100644
>>> --- a/lib/remotes/s3.c
>>> +++ b/lib/remotes/s3.c
>>> @@ -41,17 +41,16 @@ struct s3erofs_curl_request {
>>>     static int s3erofs_prepare_url(struct s3erofs_curl_request *req,
>>>                      const char *endpoint,
>>> -                   const char *path, const char *key,
>>
>> I really think we should at least add a unittest for this.
>>
> Hi Xiang,
> 
> 
> I agree that adding unit tests is necessary, but the issue is that it's difficult for us to verify the validity of the URL (and accompanying request headers) unless we actually make a request to a remote S3 service. For example, the issue described in this patch only occurs with Huawei Cloud OBS, not with Alibaba Cloud OSS.
> 
> I suggest that as a first step, we could perform basic rule-based validation of the URL in unit tests—such as checking whether the canonical query matches the URI, etc. And I will do it before submitting any patches modifying the url perparation logic in s3erofs implementaion.

I think we could just add some simple basic patterns first,
which we are all in agree that it should be generated as-is
to avoid stupid regression due to code changes.

Otherwise if there is lack of some unit tests, this piece
could be broken later.

Thanks,
Gao Xiang

> 
> In the future, we could integrate tools that simulate an S3 service (e.g., https://github.com/adobe/S3Mock) as part of our CI testing pipeline (although this still isn't sufficient to cover the compatibility differences across various cloud providers' S3 interfaces.... )
> 
> What's your opinion?
> 
> 
> Thanks,
> 
> Yifan
> 
> 
>> you could simply add
>>
>> #ifdef TEST
>> int main(int argc, char argv[])
>> {
>>     testfunc1();        // and use assert() if test fails
>>     testfunc2();
>> }
>> #endif
>>
>> and use gcc -o s3_test -Iinclude -lcurl lib/remote/s3.c to generate a test program.
>>
>> Thanks,
>> Gao Xiang
>>