implement a public pkgSystem::MultiArchSupported

Some codepaths need to check if the system (in our case usually dpkg)
supports MultiArch or not. We had copy-pasted the check so far into
these paths, but having it as a system check is better for reusability.

1 files changed, 1 insertions, 36 deletions

diff --git a/cmdline/apt-mark.cc b/cmdline/apt-mark.cc
index 02c73fc2e..20166b312 100644
--- a/cmdline/apt-mark.cc
+++ b/cmdline/apt-mark.cc
@@ -201,28 +201,7 @@ static bool DoHold(CommandLine &CmdL)
 	 Args.push_back(Opts->Value.c_str());
       }
    }
-
    size_t const BaseArgs = Args.size();
-   // we need to detect if we can qualify packages with the architecture or not
-   Args.push_back("--assert-multi-arch");
-   Args.push_back(NULL);
-
-
-   pid_t dpkgAssertMultiArch = ExecFork();
-   if (dpkgAssertMultiArch == 0)
-   {
-      std::string const chrootDir = _config->FindDir("DPkg::Chroot-Directory");
-      // redirect everything to the ultimate sink as we only need the exit-status
-      int const nullfd = open("/dev/null", O_RDONLY);
-      dup2(nullfd, STDIN_FILENO);
-      dup2(nullfd, STDOUT_FILENO);
-      dup2(nullfd, STDERR_FILENO);
-      if (chrootDir != "/" && chroot(chrootDir.c_str()) != 0 && chdir("/") != 0)
-	 _error->WarningE("getArchitecture", "Couldn't chroot into %s for dpkg --assert-multi-arch", chrootDir.c_str());
-      execvp(Args[0], (char**) &Args[0]);
-      _error->WarningE("dpkgGo", "Can't detect if dpkg supports multi-arch!");
-      _exit(2);
-   }
 
    APT::PackageList pkgset = APT::PackageList::FromCommandLine(CacheFile, CmdL.FileList + 1);
    if (pkgset.empty() == true)
@@ -244,21 +223,6 @@ static bool DoHold(CommandLine &CmdL)
 	 ++Pkg;
    }
 
-   bool dpkgMultiArch = false;
-   if (dpkgAssertMultiArch > 0)
-   {
-      int Status = 0;
-      while (waitpid(dpkgAssertMultiArch, &Status, 0) != dpkgAssertMultiArch)
-      {
-	 if (errno == EINTR)
-	    continue;
-	 _error->WarningE("dpkgGo", _("Waited for %s but it wasn't there"), "dpkg --assert-multi-arch");
-	 break;
-      }
-      if (WIFEXITED(Status) == true && WEXITSTATUS(Status) == 0)
-	 dpkgMultiArch = true;
-   }
-
    if (pkgset.empty() == true)
       return true;
 
@@ -359,6 +323,7 @@ static bool DoHold(CommandLine &CmdL)
       _exit(2);
    }
 
+   bool const dpkgMultiArch = _system->MultiArchSupported();
    FILE* dpkg = fdopen(external[1], "w");
    for (APT::PackageList::iterator Pkg = pkgset.begin(); Pkg != pkgset.end(); ++Pkg)
    {