Update netsnmp-sendmail-setup

* netsnmp-sendmail-setup: Add --deconfigure option: remove previosly
added configuration statements.

1 files changed, 153 insertions, 60 deletions

diff --git a/netsnmp-sendmail-setup b/netsnmp-sendmail-setup
index 86e8002..5e49ad6 100755
--- a/netsnmp-sendmail-setup
+++ b/netsnmp-sendmail-setup
@@ -3,3 +3,3 @@
 # This file is part of NetSNMP::Sendmail
-# Copyright (C) 2019 Sergey Poznyakoff <gray@gnu.org>
+# Copyright (C) 2019-2020 Sergey Poznyakoff <gray@gnu.org>
 #
@@ -37,2 +37,4 @@ sub addts {
 
+my $my_ts_rx = qr{^# Line added by $0 at };
+
 use constant {
@@ -44,5 +46,9 @@ use constant {
 
+use constant {
+    CMD_SETUP => 0,
+    CMD_REMOVE => 1
+};
+
 my $suppress_level = 0;
 my $dry_run;
-my $changed = 0;
 my @updated_services;
@@ -56,3 +62,3 @@ use constant {
 
-use constant MAX_SUPPRESS_LEVEL => L_NOTICE;
+use constant MAX_SUPPRESS_LEVEL => L_WARN;
 
@@ -98,2 +104,37 @@ sub restart_service {
 
+sub file_replace {
+    my ($file, $newfile) = @_;
+    my $bk = "$file~";
+    unlink $bk if -e $bk;
+    rename $file, $bk or die "can't rename $file to $bk: $!";
+    unless (rename $newfile, $file) {
+	printlog(L_WARN,
+		 "can't rename $newfile to $file: $!; restoring from backup");
+	unless (rename $bk, $file) {
+	    printlog(L_ERR, "failed to rename $bk to $file: $!");
+	    exit(EX_FATAL);
+	}
+    }
+}
+
+sub file_remline {
+    my ($file, $fd, $line, $endline) = @_;
+    $endline //= $line;
+    printlog(L_NOTICE,
+	     ($endline == $line) ? "editing $file: removing line $line"
+	     : "editing $file: removing lines $line-$endline");
+    return if $dry_run;
+    my $ofd = File::Temp->new(DIR => dirname($file), UNLINK => $dry_run);
+    seek($fd, 0, SEEK_SET) or die "seek $file: $!";
+    my $ln = 0;
+    while (<$fd>) {
+	$ln++;
+	next if ($line <= $ln && $ln <= $endline);
+	print $ofd $_;
+    }
+    close $ofd;
+    close $fd;
+    file_replace($file, $ofd->filename);
+}
+
 sub scan_snmpd_conf {
@@ -109,6 +150,16 @@ sub scan_snmpd_conf {
 	s/^\s+//;
+	
+	if (/$my_ts_rx/) {
+	    $comline = $line;
+	    next;
+	}
+	
 	if (/^perl\s+use\s+NetSNMP::Sendmail/) {
-	    printlog(L_INFO, "$file:$line: NetSNMP::Sendmail already enabled");
-	    return;
+	    if ($comline && $comline + 1 == $line) {
+		return (1, $comline, $line);
+	    } else {
+		return (1, $line);
+	    }
 	}
+	
 	if (/^perl\s+use/) {
@@ -117,3 +168,3 @@ sub scan_snmpd_conf {
     }
-    return $insert_line || $line + 1;
+    return (0, $insert_line || $line + 1);
 }
@@ -142,4 +193,4 @@ sub update_snmpd_conf {
     }
-    $changed++;
-    return $ofd;
+    close $ofd;
+    file_replace($ifile, $ofd->filename) unless ($dry_run);
 }
@@ -147,21 +198,16 @@ sub update_snmpd_conf {
 sub edit_snmpd_conf {
-    my ($name, $stmt) = @_;
+    my ($command, $name, $stmt) = @_;
     my $u = umask(077);
     if (open(my $fd, '<', $name)) {
-	if (defined(my $insert_line = scan_snmpd_conf($name, $fd))) {
-	    my $fh = update_snmpd_conf($name, $fd, $insert_line, $stmt);
-	    unless ($dry_run) {
-		my $bk = "$name~";
-		unlink $bk if -e $bk;
-		rename $name, $bk or die "can't rename $name to $bk: $!";
-		unless (rename $fh->filename, $name) {
-		    printlog(L_WARN,
-			     "can't rename ".$fh->filename." to $name: $!; restoring from backup");
-		    unless (rename $bk, $name) {
-			printlog(L_ERR, "failed to rename $bk to $name: $!");
-			exit(EX_FATAL);
-		    }
-		}
+	my ($found, $line, $endline) = scan_snmpd_conf($name, $fd);
+	if ($command == CMD_SETUP) {
+	    if ($found) {
+		printlog(L_INFO, "$name:".($endline ? $endline : $line).": NetSNMP::Sendmail already enabled");
+	    } else {
+		update_snmpd_conf($name, $fd, $line, $stmt);
+	        push @updated_services, 'snmpd';
 	    }
-	    push @updated_services, 'snmpd';
+	} elsif ($found) {
+	    file_remline($name, $fd, $line, $endline);
+            push @updated_services, 'snmpd';
 	}
@@ -212,10 +258,21 @@ sub scan_sendmail_mc {
     my $last_nl;
+    my $comline;
+    my $line = 0;
     while (<$fd>) {
+	$line++;
 	$last_nl = chomp;
 	s/^\s+//;
+
+	if (/$my_ts_rx/) {
+	    $comline = $line;
+	    next;
+	}
 	if (/^define\(\s*`?STATUS_FILE'?\s*,\s*`?(.+?)'?\s*\)/) {
 	    $name = $1;
+	    last
 	}
     }
-    return ($name, $last_nl);
+
+    return ($name, $last_nl,
+	    ($comline && $comline + 1 == $line) ? ($comline, $line) : ($line));
 }
@@ -223,35 +280,47 @@ sub scan_sendmail_mc {
 sub edit_sendmail_mc {
-    my $file = shift;
+    my ($command, $file, $default_statfile) = @_;
     if (open(my $fd, '+<', $file)) {
 	my $need_make;
-	my ($statfile, $last_nl) = scan_sendmail_mc($fd);
-	if ($statfile) {
-	    printlog(L_INFO, "status file $statfile");
-	} else {
-	    $statfile = shift;
-	    printlog(L_NOTICE, "editing $file");
-	    unless ($dry_run) {
-		seek($fd, 0, SEEK_END) or die "seek: $!";
-		print $fd "\n" unless $last_nl;
-		addts $fd;
-		print $fd "define(`STATUS_FILE', `$statfile')\n";
+	my ($statfile, $last_nl, $line, $endline) = scan_sendmail_mc($fd);
+	if ($command == CMD_SETUP) {
+	    if ($statfile) {
+		printlog(L_INFO,
+			 "$file:".($endline ? $endline : $line).
+			 ": status file $statfile already enabled");
+	    } else {
+		$statfile = $default_statfile;
+		printlog(L_NOTICE, "editing $file");
+		unless ($dry_run) {
+		    seek($fd, 0, SEEK_END) or die "seek: $!";
+		    print $fd "\n" unless $last_nl;
+		    addts $fd;
+		    print $fd "define(`STATUS_FILE', `$statfile')\n";
+		}
+	        push @updated_services, 'sendmail';
+	        $need_make = !$dry_run;
 	    }
-	    push @updated_services, 'sendmail';
-	    $need_make = 1;
-	    $changed++;
-	}
-	close $fd;
 
-	if (-f $statfile) {
-	    printlog(L_INFO, "$statfile exists");
-	} else {
-	    printlog(L_NOTICE, "creating $statfile");
-	    unless ($dry_run) {
-		if (open($fd, '>', $statfile)) {
-		    close($fd);
-		} else {
-		    warn "failed to create $statfile: $!";
+	    if (-f $statfile) {
+		printlog(L_INFO, "$statfile exists");
+	    } else {
+	        printlog(L_NOTICE, "creating $statfile");
+	        unless ($dry_run) {
+		    if (open($fd, '>', $statfile)) {
+			close($fd);
+		    } else {
+		        warn "failed to create $statfile: $!";
+		    }
 		}
 	    }
+	} elsif ($statfile) {
+	    if ($endline) {
+		file_remline($file, $fd, $line, $endline);
+   	        push @updated_services, 'sendmail';
+	        $need_make = !$dry_run;
+	    } else {
+		printlog(L_INFO,
+			 "$file:$line: retaining status file setup: not configured by $0");
+	    }
 	}
+	close $fd;
 
@@ -276,2 +345,4 @@ my $sendmail_bindir;
 
+my $command = CMD_SETUP;
+
 GetOptions('quiet|q+' => \$suppress_level,
@@ -281,5 +352,7 @@ GetOptions('quiet|q+' => \$suppress_level,
 	   'restart=s' => sub {
-	       my ($name,$command) = split /=/, $_[1], 2;
-	       $restart_override{$name} = $command;
+	       my ($name,$cmd) = split /=/, $_[1], 2;
+	       $restart_override{$name} = $cmd;
 	   },
+	   'configure' => sub { $command = CMD_SETUP },
+	   'deconfigure' => sub { $command = CMD_REMOVE },
 	   'help' => sub {
@@ -300,5 +373,5 @@ if ($suppress_level > MAX_SUPPRESS_LEVEL) {
 check_module;
-check_file $snmpd_conf;
-check_file $sendmail_mc;
-check_file '/etc/mail/Makefile';
+check_file($snmpd_conf);
+check_file($sendmail_mc);
+check_file('/etc/mail/Makefile');
 
@@ -316,4 +389,4 @@ $stmt .= ';';
 
-edit_sendmail_mc($sendmail_mc, $sendmail_statfile);
-edit_snmpd_conf($snmpd_conf, $stmt);
+edit_sendmail_mc($command, $sendmail_mc, $sendmail_statfile);
+edit_snmpd_conf($command, $snmpd_conf, $stmt);
 
@@ -321,3 +394,3 @@ map { restart_service($_) } @updated_services;
 
-exit($changed ? EX_OK : EX_UNCHANGED);
+exit(@updated_services ? EX_OK : EX_UNCHANGED);
 
@@ -333,2 +406,4 @@ B<netsnmp-sendmail-setup>
 [B<--bindir=I<DIR>>]
+[B<--configure>]
+[B<--deconfigure>]
 [B<--dry-run>]
@@ -337,3 +412,3 @@ B<netsnmp-sendmail-setup>
 [B<--restart=I<service>=I<command>>]
-
+    
 B<netsnmp-sendmail-setup> B<--help> | B<--usage>
@@ -348,2 +423,11 @@ directory. Finally, the file F</etc/snmp/snmpd.conf> is scanned for the
 B<perl use NetSNMP::Sendmail> statement. It is added if not already present.
+Each added configuration line is preceded by a comment stating that it
+was added by the script.
+
+When run with the B<--deconfigure> option, the reverse operation is
+performed.  The B<NetSNMP::Sendmail> configuration statement is removed
+from the snmpd configuration unconditionally.  The B<STATUS_FILE> clause
+is removed from F</etc/mail/sendmail.mc> only if it is preceded by the
+B<netsnmp-sendmail-setup> comment marker.  The status file itself is
+never removed.
 
@@ -362,2 +446,11 @@ directory is picked up automatically.
 
+=item B<--configure>
+
+A no-op option included for symmetry with B<--deconfigure>.    
+
+=item B<--deconfigure>
+
+Remove the configuration statements previously added to the snmdp and
+sendmail configuration files.    
+    
 =item B<-n>, B<--dry-run>