[BUG] ROS3 header search is case-sensitive

[berghaus]

Describe the bug Looking up the content length header in the ROS3 VFD is case-sensitive at H5FDs3comms.c:944. That means, ROS3 finds Content-Length: ..., but fails to find content-length: ....

Expected behavior Headers are supposed to be case-insensitive ASCII strings (RFC 7230, RFC 7540). So, both Content-Length: ... and content-length: ... should be matched.

Platform (please complete the following information)

• HDF5 version 1.12.2
• OS and version: Debian 11
• Compiler and version: gcc (Debian 10.2.1-6) 10.2.1 20210110
• Build system: Package: autotools-dev Version: 20180224.1+nmu1
• Any configure options you specified: --enable-ros3_vfd

Additional context Opening files using ROS3 VFD from a Ceph implementation of S3 fails. Opening the same file/object from AWS works. The reported error is that the 'Content-Length' header cannot be found. Indeed, Ceph advertises content-length while AWS advertises Content-Length:

$ curl --head "https://cephs3.../hdf5/snp500.h5"
HTTP/1.1 200 OK
content-length: 113404160
...

$ curl --head "http://aws.../hdf5/snp500.h5"
HTTP/1.1 200 OK
Content-Length: 113404160

It is rather unfortunate that case-insensitive string search is non-standard.

[byrnHDF]

Windows link fails when StrStrIA actually used in S3 code.

[mattjala]

Already fixed in #2101/#2114