[v3,1/3] buildman: Support building within a Python venv

The Python virtualenv tool sets up a few things in the environment,
putting its path first in the PATH environment variable and setting up
a sys.prefix different from the sys.base_prefix value.

At present buildman puts the toolchain path first in PATH so that it can
be found easily during the build. For sandbox this causes problems since
/usr/bin/gcc (for example) results in '/usr/bin' being prepended to the
PATH variable. As a result, the venv is partially disabled.

The result is that sandbox builds within a venv ignore the venv, e.g.
when looking for packages.

Correct this by detecting the venv and adding the toolchain path after
the venv path.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

(no changes since v2)

Changes in v2:
- Fix 'envronment' typo

 tools/buildman/bsettings.py |  3 ++
 tools/buildman/test.py      | 84 +++++++++++++++++++++++++++++++++++++
 tools/buildman/toolchain.py | 31 ++++++++++++--
 3 files changed, 114 insertions(+), 4 deletions(-)

Hi Tom,

On Thu, 15 Aug 2024 at 13:57, Simon Glass <sjg@chromium.org> wrote:
>
> The Python virtualenv tool sets up a few things in the environment,
> putting its path first in the PATH environment variable and setting up
> a sys.prefix different from the sys.base_prefix value.
>
> At present buildman puts the toolchain path first in PATH so that it can
> be found easily during the build. For sandbox this causes problems since
> /usr/bin/gcc (for example) results in '/usr/bin' being prepended to the
> PATH variable. As a result, the venv is partially disabled.
>
> The result is that sandbox builds within a venv ignore the venv, e.g.
> when looking for packages.
>
> Correct this by detecting the venv and adding the toolchain path after
> the venv path.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
> (no changes since v2)
>
> Changes in v2:
> - Fix 'envronment' typo
>
>  tools/buildman/bsettings.py |  3 ++
>  tools/buildman/test.py      | 84 +++++++++++++++++++++++++++++++++++++
>  tools/buildman/toolchain.py | 31 ++++++++++++--
>  3 files changed, 114 insertions(+), 4 deletions(-)
>
> diff --git a/tools/buildman/bsettings.py b/tools/buildman/bsettings.py
> index aea724fc559..a7358cfc08a 100644
> --- a/tools/buildman/bsettings.py
> +++ b/tools/buildman/bsettings.py
> @@ -31,6 +31,9 @@ def setup(fname=''):
>  def add_file(data):
>      settings.read_file(io.StringIO(data))
>
> +def add_section(name):
> +    settings.add_section(name)
> +
>  def get_items(section):
>      """Get the items from a section of the config.
>
> diff --git a/tools/buildman/test.py b/tools/buildman/test.py
> index bfad3093030..6191af95445 100644
> --- a/tools/buildman/test.py
> +++ b/tools/buildman/test.py
> @@ -148,6 +148,7 @@ class TestBuild(unittest.TestCase):
>          self.toolchains.Add('arm-linux-gcc', test=False)
>          self.toolchains.Add('sparc-linux-gcc', test=False)
>          self.toolchains.Add('powerpc-linux-gcc', test=False)
> +        self.toolchains.Add('/path/to/aarch64-linux-gcc', test=False)
>          self.toolchains.Add('gcc', test=False)
>
>          # Avoid sending any output
> @@ -868,6 +869,89 @@ class TestBuild(unittest.TestCase):
>              self.assertEqual([4, 5], control.read_procs(tmpdir))
>              self.assertEqual(self.finish_time, self.cur_time)
>
> +    def call_make_environment(self, tchn, full_path, in_env=None):
> +        """Call Toolchain.MakeEnvironment() and process the result
> +
> +        Args:
> +            tchn (Toolchain): Toolchain to use
> +            full_path (bool): True to return the full path in CROSS_COMPILE
> +                rather than adding it to the PATH variable
> +            in_env (dict): Input environment to use, None to use current env
> +
> +        Returns:
> +            tuple:
> +                dict: Changes that MakeEnvironment has made to the environment
> +                    key: Environment variable that was changed
> +                    value: New value (for PATH this only includes components
> +                        which were added)
> +                str: Full value of the new PATH variable
> +        """
> +        env = tchn.MakeEnvironment(full_path, env=in_env)
> +
> +        # Get the original environment
> +        orig_env = dict(os.environb if in_env is None else in_env)
> +        orig_path = orig_env[b'PATH'].split(b':')
> +
> +        # Find new variables
> +        diff = dict((k, env[k]) for k in env if orig_env.get(k) != env[k])
> +
> +        # Find new / different path components
> +        diff_path = None
> +        new_path = None
> +        if b'PATH' in diff:
> +            new_path = diff[b'PATH'].split(b':')
> +            diff_paths = [p for p in new_path if p not in orig_path]
> +            diff_path = b':'.join(p for p in new_path if p not in orig_path)
> +            if diff_path:
> +                diff[b'PATH'] = diff_path
> +            else:
> +                del diff[b'PATH']
> +        return diff, new_path
> +
> +    def test_toolchain_env(self):
> +        """Test PATH and other environment settings for toolchains"""
> +        # Use a toolchain which has a path, so that full_path makes a difference
> +        tchn = self.toolchains.Select('aarch64')
> +
> +        # Normal cases
> +        diff = self.call_make_environment(tchn, full_path=False)[0]
> +        self.assertEqual(
> +            {b'CROSS_COMPILE': b'aarch64-linux-', b'LC_ALL': b'C',
> +             b'PATH': b'/path/to'}, diff)
> +
> +        diff = self.call_make_environment(tchn, full_path=True)[0]
> +        self.assertEqual(
> +            {b'CROSS_COMPILE': b'/path/to/aarch64-linux-', b'LC_ALL': b'C'},
> +            diff)
> +
> +        # When overriding the toolchain, only LC_ALL should be set
> +        tchn.override_toolchain = True
> +        diff = self.call_make_environment(tchn, full_path=True)[0]
> +        self.assertEqual({b'LC_ALL': b'C'}, diff)
> +
> +        # Test that virtualenv is handled correctly
> +        tchn.override_toolchain = False
> +        sys.prefix = '/some/venv'
> +        env = dict(os.environb)
> +        env[b'PATH'] = b'/some/venv/bin:other/things'
> +        tchn.path = '/my/path'
> +        diff, diff_path = self.call_make_environment(tchn, False, env)
> +
> +        self.assertIn(b'PATH', diff)
> +        self.assertEqual([b'/some/venv/bin', b'/my/path', b'other/things'],
> +                         diff_path)
> +        self.assertEqual(
> +            {b'CROSS_COMPILE': b'aarch64-linux-', b'LC_ALL': b'C',
> +             b'PATH': b'/my/path'}, diff)
> +
> +        # Handle a toolchain wrapper
> +        tchn.path = ''
> +        bsettings.add_section('toolchain-wrapper')
> +        bsettings.set_item('toolchain-wrapper', 'my-wrapper', 'fred')
> +        diff = self.call_make_environment(tchn, full_path=True)[0]
> +        self.assertEqual(
> +            {b'CROSS_COMPILE': b'fred aarch64-linux-', b'LC_ALL': b'C'}, diff)
> +
>
>  if __name__ == "__main__":
>      unittest.main()
> diff --git a/tools/buildman/toolchain.py b/tools/buildman/toolchain.py
> index 324ad0e0821..6ca79c2c0f9 100644
> --- a/tools/buildman/toolchain.py
> +++ b/tools/buildman/toolchain.py
> @@ -172,13 +172,14 @@ class Toolchain:
>          else:
>              raise ValueError('Unknown arg to GetEnvArgs (%d)' % which)
>
> -    def MakeEnvironment(self, full_path):
> +    def MakeEnvironment(self, full_path, env=None):
>          """Returns an environment for using the toolchain.
>
>          This takes the current environment and adds CROSS_COMPILE so that
>          the tool chain will operate correctly. This also disables localized
>          output and possibly Unicode encoded output of all build tools by
> -        adding LC_ALL=C.
> +        adding LC_ALL=C. For the case where full_path is False, it prepends
> +        the toolchain to PATH
>
>          Note that os.environb is used to obtain the environment, since in some
>          cases the environment many contain non-ASCII characters and we see
> @@ -187,15 +188,21 @@ class Toolchain:
>            UnicodeEncodeError: 'utf-8' codec can't encode characters in position
>               569-570: surrogates not allowed
>
> +        When running inside a Python venv, care is taken not to put the
> +        toolchain path before the venv path, so that builds initiated by
> +        buildman will still respect the venv.
> +
>          Args:
>              full_path: Return the full path in CROSS_COMPILE and don't set
>                  PATH
> +            env (dict of bytes): Original environment, used for testing
>          Returns:
>              Dict containing the (bytes) environment to use. This is based on the
>              current environment, with changes as needed to CROSS_COMPILE, PATH
>              and LC_ALL.
>          """
> -        env = dict(os.environb)
> +        env = dict(env or os.environb)
> +
>          wrapper = self.GetWrapper()
>
>          if self.override_toolchain:
> @@ -206,7 +213,23 @@ class Toolchain:
>                  wrapper + os.path.join(self.path, self.cross))
>          else:
>              env[b'CROSS_COMPILE'] = tools.to_bytes(wrapper + self.cross)
> -            env[b'PATH'] = tools.to_bytes(self.path) + b':' + env[b'PATH']
> +
> +            # Detect a Python virtualenv and avoid defeating it
> +            if sys.prefix != sys.base_prefix:
> +                paths = env[b'PATH'].split(b':')
> +                new_paths = []
> +                to_insert = tools.to_bytes(self.path)
> +                insert_after = tools.to_bytes(sys.prefix)
> +                for path in paths:
> +                    new_paths.append(path)
> +                    if to_insert and path.startswith(insert_after):
> +                        new_paths.append(to_insert)
> +                        to_insert = None
> +                if to_insert:
> +                    new_paths.append(to_insert)
> +                env[b'PATH'] = b':'.join(new_paths)
> +            else:
> +                env[b'PATH'] = tools.to_bytes(self.path) + b':' + env[b'PATH']
>
>          env[b'LC_ALL'] = b'C'
>
> --
> 2.34.1
>

Can this one be picked up please? It fixes something and Jerome's
series should really go on top of it.

Regards,
Simon