[giuseppe]

Replace the custom read-file.c/read-file.h (Apache-2.0 licensed) with json-c's json_object_from_file() and json_object_from_fd(), which parse JSON directly from a file path or descriptor without buffering the entire file into memory first.

This resolves the license incompatibility with GPL-2.0 consumers like crun (issue #174).

Closes: #174

[giuseppe]

@jnovy PTAL

[jnovy]

fileno() returns -1 for FILE* streams created by fmemopen(), open_memstream(), or any other non-fd-backed stream. This breaks libocispec's own fuzzer (src/ocispec/validate.c), which uses fmemopen()

Instead of fileno() + json_object_from_fd(), use fread() in a loop to read the stream contents, then parse with json_tokener_parse()?

[giuseppe]

thanks, what do you think of the new version?

[giuseppe]

nevermind, it breaks the CI, taking a look...

[giuseppe]

finally green

[jnovy]

LGTM

I'd add ferror() check after the fread loop (small robustness improvement) Something like this:

  while ((nread = fread (tmp, 1, sizeof (tmp), stream)) > 0)
    { ... }
  if (buf == NULL)  # only checks empty stream, not I/O error

fread() returns 0 on both EOF and error. Without checking ferror(stream) after the loop, an I/O error mid-stream will be silently treated as EOF, and the code will attempt to parse whatever partial data was read. The old fread_file() code did check ferror(stream). Suggested fix:

  if (ferror (stream))
    {
      *err = strdup ("error reading file stream");
      return NULL;
    }

[giuseppe]

good call! Added

[giuseppe]

@jnovy OK with the last version?

[flouthoc]

LGTM

[jnovy]

LGTM