[PATCH v3 3/7] virdnsmasq: Lookup DNSMASQ in PATH

[Andrea Bolognani]

On Wed, Jan 12, 2022 at 09:47:54AM +0100, Michal Privoznik wrote:
> With this code in place, the virFileIsExecutable() check can be
> removed from dnsmasqCapsRefreshInternal() because
> virFindFileInPath() already made sure the binary is executable.
>
> But introducing virFileIsExecutable() means we have to mock it in

I believe you meant virFindFileInPath() here.

> +++ b/src/util/virdnsmasq.c
> @@ -702,14 +692,20 @@ dnsmasqCapsRefreshInternal(dnsmasqCaps *caps, bool force)
>  static dnsmasqCaps *
>  dnsmasqCapsNewEmpty(void)
>  {
> -    dnsmasqCaps *caps;
> +    g_autoptr(dnsmasqCaps) caps = NULL;
>
>      if (dnsmasqCapsInitialize() < 0)
>          return NULL;
>      if (!(caps = virObjectNew(dnsmasqCapsClass)))
>          return NULL;
> -    caps->binaryPath = g_strdup(DNSMASQ);
> -    return caps;
> +
> +    if (!(caps->binaryPath = virFindFileInPath(DNSMASQ))) {
> +        virReportSystemError(ENOENT, "%s",
> +                             _("Unable to find 'dnsmasq' binary in $PATH"));
> +        return NULL;
> +    }
> +
> +    return g_steal_pointer(&caps);
>  }

Can you please squash the g_autoptr conversion into the previous
patch?

> +++ b/tests/networkmock.c
> @@ -0,0 +1,30 @@
> +/*
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library.  If not, see
> + * <http://www.gnu.org/licenses/>.
> + */

Missing copyright information. Also can we have an SPDX tag instead
of the full license blurb? See tests/virhostdevmock.c for an example
of what I have in mind.

> +char *
> +virFindFileInPath(const char *file)
> +{
> +    if (file && g_strrstr(file, "dnsmasq"))
> +        return g_strdup(file);

This mock is somewhat inaccurate because, if dnsmasq was not found at
configure time, then DNSMASQ will be defined to "dnsmasq" and the
mocked function will return that string instead of an absolute path.
Clearly this doesn't break the test case, but it still feels off.

I wonder if we should drop the configure time detection for dnsmasq
altogether, same as we've done for other optional binaries, always
define DNSMASQ to be "dnsmasq", and here do

  if (STREQ_NULLABLE(file, "dnsmasq"))
      return g_strdup("/usr/bin/dnsmasq");

What do you think?

-- 
Andrea Bolognani / Red Hat / Virtualization