Re: [PATCH v3 0/9] Split fsverity-utils into a shared library

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Mar 12, 2020 at 05:47:49PM -0400, Jes Sorensen wrote:
> From: Jes Sorensen <jsorensen@fb.com>
> 
> Hi,
> 
> This is an updated version of my patches to split fsverity-utils into
> a shared library. This version addresses most of the comments I
> received in the last version:
> 
> 1) Document the API
> 2) Verified ran xfstest against the build
> 3) Make struct fsverity_descriptor private
> 4) Reviewed (and documented) error codes
> 5) Improved validation of input parameters, and return error if any
>    reserved field is not zero.
> 
> I left struct fsverity_hash_alg in the public API, because it adds
> useful information to the user, in particular providing the digest
> size, and allows the caller to walk the list to obtain the supported
> algorithms. The alternative is to introduce a
> libverity_get_digest_size() call.
> 
> I still need to add some self-tests to the build and deal with the
> soname stuff.
> 
> Next up is rpm support.
> 
> Cheers,
> Jes
> 
> 
> Jes Sorensen (9):
>   Build basic shared library framework
>   Change compute_file_measurement() to take a file descriptor as
>     argument
>   Move fsverity_descriptor definition to libfsverity.h
>   Move hash algorithm code to shared library
>   Create libfsverity_compute_digest() and adapt cmd_sign to use it
>   Introduce libfsverity_sign_digest()
>   Validate input arguments to libfsverity_compute_digest()
>   Validate input parameters for libfsverity_sign_digest()
>   Document API of libfsverity
> 
>  Makefile              |  18 +-
>  cmd_enable.c          |  11 +-
>  cmd_measure.c         |   4 +-
>  cmd_sign.c            | 526 +++------------------------------------
>  fsverity.c            |  16 +-
>  hash_algs.c           |  26 +-
>  hash_algs.h           |  27 --
>  libfsverity.h         | 127 ++++++++++
>  libfsverity_private.h |  33 +++
>  libverity.c           | 559 ++++++++++++++++++++++++++++++++++++++++++
>  util.h                |   2 +
>  11 files changed, 801 insertions(+), 548 deletions(-)
>  create mode 100644 libfsverity.h
>  create mode 100644 libfsverity_private.h
>  create mode 100644 libverity.c

Have you tried using the library?  It doesn't work for me because it uses
functions from util.c which aren't compiled in:

test.c:

	#include "libfsverity.h"

	int main() { }

$ gcc test.c -L. -lfsverity

/usr/bin/ld: ./libfsverity.so: undefined reference to `do_error_msg'
/usr/bin/ld: ./libfsverity.so: undefined reference to `error_msg_errno'
/usr/bin/ld: ./libfsverity.so: undefined reference to `error_msg'
/usr/bin/ld: ./libfsverity.so: undefined reference to `fatal_error'
/usr/bin/ld: ./libfsverity.so: undefined reference to `assertion_failed'
/usr/bin/ld: ./libfsverity.so: undefined reference to `xmalloc'
/usr/bin/ld: ./libfsverity.so: undefined reference to `xzalloc'
/usr/bin/ld: ./libfsverity.so: undefined reference to `xmemdup'

- Eric