refactor(utils): centralize executable lookup

build-ubunturepo

@@ -363,6 +363,7 @@ then
                         #3 symbolic link can't work during package
                         if [ $file_low = "xcat-probe" ]; then
                             mkdir -p ${CURDIR}/lib/perl/xCAT/
+                            cp -f ${CURDIR}/../perl-xCAT/xCAT/CommandUtils.pm ${CURDIR}/lib/perl/xCAT/
                             cp -f ${CURDIR}/../perl-xCAT/xCAT/NetworkUtils.pm ${CURDIR}/lib/perl/xCAT/
                             cp -f ${CURDIR}/../perl-xCAT/xCAT/GlobalDef.pm ${CURDIR}/lib/perl/xCAT/
                             cp -f ${CURDIR}/../perl-xCAT/xCAT/ServiceNodeUtils.pm ${CURDIR}/lib/perl/xCAT/

build-utils/lib/XCAT/BuildUtils.pm

@@ -141,6 +141,7 @@ sub usage {
 }
 
 use constant XCAT_PROBE_HELPERS => qw(
+    CommandUtils.pm
     GlobalDef.pm
     NetworkUtils.pm
     ServiceNodeUtils.pm

buildrpms.pl

@@ -65,6 +65,7 @@ system('mkdir', '-p', map { "$ENV{HOME}/rpmbuild/$_" } qw(SOURCES SPECS BUILD BU
 my $VERSION = read_line("Version") // die "Cannot read Version\n";
 my $PWD = Cwd::cwd();
 my @XCAT_PROBE_HELPERS = qw(
+    CommandUtils.pm
     GlobalDef.pm
     NetworkUtils.pm
     ServiceNodeUtils.pm

perl-xCAT/xCAT/CommandUtils.pm

@@ -0,0 +1,54 @@
+package xCAT::CommandUtils;
+
+use strict;
+use warnings;
+
+our @SYSTEM_FALLBACK_DIRS = qw(
+  /usr/sbin
+  /usr/bin
+  /sbin
+  /bin
+);
+
+=head1 NAME
+
+xCAT::CommandUtils - dependency-light command lookup helpers
+
+=head1 FUNCTIONS
+
+=head2 find_executable
+
+Find an executable by searching PATH in order, followed by the standard system
+directories. Pass C<path =E<gt> $value> to search that value instead of the
+process PATH. Like the callers this function replaces, empty entries and an
+entry named C<0> are ignored. Pass C<fallback_dirs =E<gt> []> to disable the
+standard fallbacks, or supply an array reference to replace them. The matching
+candidate path is returned, or undef when none is found.
+
+=cut
+
+sub find_executable {
+    my ( $command, %args ) = @_;
+
+    return unless defined($command) && length($command);
+
+    my $path = exists( $args{path} ) ? $args{path} : $ENV{PATH};
+    foreach my $dir ( split /:/, $path || '' ) {
+        next unless $dir;
+        my $candidate = "$dir/$command";
+        return $candidate if -x $candidate;
+    }
+
+    my $fallback_dirs = exists( $args{fallback_dirs} )
+      ? $args{fallback_dirs}
+      : \@SYSTEM_FALLBACK_DIRS;
+    foreach my $dir ( @{ $fallback_dirs || [] } ) {
+        next unless defined($dir) && length($dir);
+        my $candidate = "$dir/$command";
+        return $candidate if -x $candidate;
+    }
+
+    return;
+}
+
+1;

perl-xCAT/xCAT/DHCP/Backend.pm

@@ -3,6 +3,7 @@ package xCAT::DHCP::Backend;
 use strict;
 use warnings;
 
+use xCAT::CommandUtils;
 use xCAT::StringUtils qw(trim);
 
 my %valid_backend = map { $_ => 1 } qw(auto isc kea);
@@ -142,18 +143,7 @@ sub _osver {
 
 sub _command_exists {
     my ($command) = @_;
-
-    foreach my $dir ( split /:/, $ENV{PATH} || '' ) {
-        next unless $dir;
-        my $path = "$dir/$command";
-        return 1 if -x $path;
-    }
-
-    foreach my $path ( "/usr/sbin/$command", "/usr/bin/$command", "/sbin/$command", "/bin/$command" ) {
-        return 1 if -x $path;
-    }
-
-    return 0;
+    return xCAT::CommandUtils::find_executable($command) ? 1 : 0;
 }
 
 1;

perl-xCAT/xCAT/DHCP/Backend/Kea.pm

@@ -8,6 +8,7 @@ use File::Basename;
 use File::Path qw/make_path/;
 use Math::BigInt;
 use Text::ParseWords qw/shellwords/;
+use xCAT::CommandUtils;
 use xCAT::DHCP::Range;
 use xCAT::NetworkUtils;
 
@@ -1206,18 +1207,7 @@ sub _expand_kea_build_path {
 
 sub _command_path {
     my ($command) = @_;
-
-    foreach my $dir ( split /:/, $ENV{PATH} || '' ) {
-        next unless $dir;
-        my $path = "$dir/$command";
-        return $path if -x $path;
-    }
-
-    foreach my $path ( "/usr/sbin/$command", "/usr/bin/$command", "/sbin/$command", "/bin/$command" ) {
-        return $path if -x $path;
-    }
-
-    return;
+    return xCAT::CommandUtils::find_executable($command);
 }
 
 sub _shell_quote {

xCAT-probe/lib/perl/probe_utils.pm

@@ -8,6 +8,7 @@ use File::Copy;
 use Time::Local;
 use Socket;
 use List::Util qw/sum/;
+use xCAT::CommandUtils;
 
 #-----------------------------------------
 
@@ -175,11 +176,7 @@ sub _netplan_get {
 
 sub _command_available {
     my $cmd = shift;
-    for my $dir (split /:/, $ENV{PATH} || '') {
-        next unless $dir;
-        return 1 if -x "$dir/$cmd";
-    }
-    return 0;
+    return xCAT::CommandUtils::find_executable( $cmd, fallback_dirs => [] ) ? 1 : 0;
 }
 
 sub _capture_command {

xCAT-server/lib/xcat/plugins/dhcp.pm

@@ -24,6 +24,7 @@ use Getopt::Long;
 Getopt::Long::Configure("bundling");
 Getopt::Long::Configure("pass_through");
 use Socket;
+use xCAT::CommandUtils;
 my $candoipv6 = eval {
     require Socket6;
     1;
@@ -3185,18 +3186,7 @@ sub local_ipv4_routes
 sub kea_command_path
 {
     my ($command) = @_;
-
-    foreach my $dir (split /:/, $ENV{PATH} || '') {
-        next unless $dir;
-        my $path = "$dir/$command";
-        return $path if -x $path;
-    }
-
-    foreach my $path ( "/usr/sbin/$command", "/usr/bin/$command", "/sbin/$command", "/bin/$command" ) {
-        return $path if -x $path;
-    }
-
-    return;
+    return xCAT::CommandUtils::find_executable($command);
 }
 
 sub kea_subnet4_intent