Re: [PATCH v2 02/12] tests/docker: better handle symlinked libs

[Robert Foley]

Hi,
I was looking at this patch and have a comment about the number of
groups that are expected to be found by this regex.
It seems like the old code expected two groups to be found otherwise
it will not append the library to the found libs.
def _get_so_libs(executable):
    libs = []
    ldd_re = re.compile(r"(/.*/)(\S*)")
    try:
        ldd_output = subprocess.check_output(["ldd",
executable]).decode('utf-8')
        for line in ldd_output.split("\n"):
            search = ldd_re.search(line)
            if search and len(search.groups()) == 2:  <<<<<<<<<<<<<<<
                so_path = search.groups()[0]
                so_lib = search.groups()[1]
                libs.append("%s/%s" % (so_path, so_lib))

I did a bit of experimenting with output from ldd and found a few
strings where the new regex seems
to generate only one group for the entire path+lib rather than one group
for the path and another group for the lib.

$ ldd build/aarch64-softmmu/qemu-system-aarch64
__snip__
      /lib/ld-linux-aarch64.so.1 (0x0000ffff9c41f000)
      libgmodule-2.0.so.0 =>
/usr/lib/aarch64-linux-gnu/libgmodule-2.0.so.0 (0x0000ffff9a96e000)
__snip
$ python3
Python 3.6.8 (default, Oct  7 2019, 12:59:55)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> ldd_re = re.compile(r"(?:\S+ => )?(\S*) \(:?0x[0-9a-f]+\)")
>>> a = "/lib/ld-linux-aarch64.so.1 (0x0000ffff9c41f000)"
>>> b = "libgmodule-2.0.so.0 => /usr/lib/aarch64-linux-gnu/libgmodule-2.0.so.0 
>>> (0x0000ffff9a96e000)"
>>> ldd_re.search(a).groups()
('/lib/ld-linux-aarch64.so.1',)
>>> ldd_re.search(b).groups()
('/usr/lib/aarch64-linux-gnu/libgmodule-2.0.so.0',)
>>> len(ldd_re.search(a).groups())
1
>>> len(ldd_re.search(b).groups())
1
>>> ldd_re_old = re.compile('(/.*/)(\S*)')
>>> ldd_re_old.search(a).groups()
('/lib/', 'ld-linux-aarch64.so.1')
>>> ldd_re_old.search(b).groups()
('/usr/lib/aarch64-linux-gnu/', 'libgmodule-2.0.so.0')
>>> len(ldd_re_old.search(a).groups())
2
>>> len(ldd_re_old.search(b).groups())
2
>>>

Thanks & Regards,
-Rob

On Thu, 30 Jan 2020 at 06:40, Alex Bennée <address@hidden> wrote:
>
> When we are copying we want to ensure we grab the first
> resolution (the found in path section). However even that binary might
> be a symlink so lets make sure we chase the symlinks to copy the right
> binary to where it can be found.
>
> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  tests/docker/docker.py | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> diff --git a/tests/docker/docker.py b/tests/docker/docker.py
> index 31d8adf836..7dfca63fe4 100755
> --- a/tests/docker/docker.py
> +++ b/tests/docker/docker.py
> @@ -109,7 +109,7 @@ def _get_so_libs(executable):
>      ensure theright data is copied."""
>
>      libs = []
> -    ldd_re = re.compile(r"(/.*/)(\S*)")
> +    ldd_re = re.compile(r"(?:\S+ => )?(\S*) \(:?0x[0-9a-f]+\)")
>      try:
>          ldd_output = subprocess.check_output(["ldd", 
> executable]).decode('utf-8')
>          for line in ldd_output.split("\n"):
> @@ -145,7 +145,8 @@ def _copy_binary_with_libs(src, bin_dest, dest_dir):
>      if libs:
>          for l in libs:
>              so_path = os.path.dirname(l)
> -            _copy_with_mkdir(l, dest_dir, so_path)
> +            real_l = os.path.realpath(l)
> +            _copy_with_mkdir(real_l, dest_dir, so_path)
>  def _check_binfmt_misc(executable):
> --
> 2.20.1
>