dpkg-architecture: Add architecture restriction options for -L

This allows to select specific subsets of all valid known architectures,
matching by wildcard (-W), endianness (-E) or bits (-B). The restricting
options can be combined, or omitted altogether.

Closes: #762635

debian/changelog

@@ -96,6 +96,10 @@ dpkg (1.17.14) UNRELEASED; urgency=low
     if stdin is a pipe instead of the current terminal. Closes: #762391
   * Add a new --hash option to enable generating only specific file checksums
     in dpkg-scanpackages. Requested by Thorsten Glaser <tg@debian.org>.
+  * Add architecture restriction options for dpkg-architecture -L. This allows
+    to select specific subsets of all valid known architectures, matching by
+    wildcard (-W), endianness (-E) or bits (-B). The restricting options can
+    be combined, or omitted altogether. Closes: #762635
 
   [ Raphaël Hertzog ]
   * Explain better in deb-triggers(5) why interest/activate-noawait should be

man/dpkg-architecture.1

@@ -81,6 +81,8 @@ the determined value.
 .TP
 .B \-L
 Print a list of valid architecture names.
+Possibly restricted by one or more of the matching options \fB\-W\fP,
+\fB\-B\fP or \fB\-E\fP (since dpkg 1.17.14).
 .TP
 .BR \-? ", " \-\-help
 Show the usage message and exit.
@@ -104,6 +106,18 @@ run on the host architecture, and to build code for the target architecture.
 .BI \-T gnu-system-type
 Set the target GNU system type.
 .TP
+.BI \-W architecture-wildcard
+Restrict the architectures listed by \fB\-L\fP to ones matching the specified
+architecture wildcard (since dpkg 1.17.14).
+.TP
+.BI \-B architecture-bits
+Restrict the architectures listed by \fB\-L\fP to ones with the specified
+CPU bits (since dpkg 1.17.14). Either \fB32\fP or \fB64\fP.
+.TP
+.BI \-E architecture-endianness
+Restrict the architectures listed by \fB\-L\fP to ones with the specified
+endianness (since dpkg 1.17.14). Either \fBlittle\fP or \fBbig\fP.
+.TP
 .B \-f
 Values set by existing environment variables with the same name as used by
 the scripts are honored (i.e. used by \fBdpkg\-architecture\fP), except if

scripts/dpkg-architecture.pl

@@ -48,7 +48,7 @@ sub usage {
     . "\n\n" . _g(
 'Commands:
   -l                 list variables (default).
-  -L                 list valid architectures.
+  -L                 list valid architectures (matching some criteria).
   -e<debian-arch>    compare with host Debian architecture.
   -i<arch-alias>     check if host Debian architecture is <arch-alias>.
   -q<variable>       prints only the value of <variable>.
@@ -63,6 +63,9 @@ sub usage {
   -t<gnu-system>     set host GNU system type.
   -A<debian-arch>    set target Debian architecture.
   -T<gnu-system>     set target GNU system type.
+  -W<arch-wildcard>  restrict listed architectures matching <arch-wildcard>.
+  -B<arch-bits>      restrict listed architectures matching <arch-bits>.
+  -E<arch-endian>    restrict listed architectures matching <arch-endian>.
   -f                 force flag (override variables set in environment).')
     . "\n", $Dpkg::PROGNAME;
 }
@@ -151,6 +154,9 @@ my $req_target_arch = '';
 my $req_target_gnu_type = '';
 my $req_eq_arch = '';
 my $req_is_arch = '';
+my $req_match_wildcard = '';
+my $req_match_bits = '';
+my $req_match_endian = '';
 my $req_variable_to_print;
 my $action = 'l';
 my $force = 0;
@@ -170,6 +176,12 @@ while (@ARGV) {
 	$req_target_arch = ${^POSTMATCH};
     } elsif (m/^-T/p) {
 	$req_target_gnu_type = ${^POSTMATCH};
+    } elsif (m/^-W/p) {
+	$req_match_wildcard = ${^POSTMATCH};
+    } elsif (m/^-B/p) {
+	$req_match_bits = ${^POSTMATCH};
+    } elsif (m/^-E/p) {
+	$req_match_endian = ${^POSTMATCH};
     } elsif (m/^-e/p) {
 	$req_eq_arch = ${^POSTMATCH};
 	$req_vars = $arch_vars{DEB_HOST_ARCH};
@@ -334,6 +346,12 @@ if ($action eq 'l') {
     print "$v{$req_variable_to_print}\n";
 } elsif ($action eq 'L') {
     foreach my $arch (get_valid_arches()) {
-       print "$arch\n";
+        my ($bits, $endian) = debarch_to_cpuattrs($arch);
+
+        next if $req_match_endian and $endian ne $req_match_endian;
+        next if $req_match_bits and $bits ne $req_match_bits;
+        next if $req_match_wildcard and not debarch_is($arch, $req_match_wildcard);
+
+        print "$arch\n";
     }
 }