git-send-email: ssh/login style password requests

Whilst convenient, it is most unwise to record passwords
in any place but one's brain. Moreover, it is especially
foolish to store them in configuration files, even with
access permissions set accordingly.

git-send-email has been amended, so that if it detects
an smtp username without a password, it promptly prompts
for the password and masks the input for privacy.

Furthermore, the argument to --smtp-pass has been rendered
optional.

The documentation has been updated to reflect these changes.

Signed-off-by: Michael Witten <mfwitten@mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 55 insertions, 9 deletions

diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 0554f2b374..4f4caa402d 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -96,11 +96,40 @@ The --cc option must be repeated for each user you want on the cc list.
 	servers typically listen to smtp port 25 and ssmtp port
 	465).
 
---smtp-user, --smtp-pass::
-	Username and password for SMTP-AUTH. Defaults are the values of
-	the configuration values 'sendemail.smtpuser' and
-	'sendemail.smtppass', but see also 'sendemail.identity'.
-	If not set, authentication is not attempted.
+--smtp-user::
+	Username for SMTP-AUTH. In place of this option, the following
+	configuration variables can be specified:
++
+--
+		* sendemail.smtpuser
+		* sendemail.<identity>.smtpuser (see sendemail.identity).
+--
++
+However, --smtp-user always overrides these variables.
++
+If a username is not specified (with --smtp-user or a
+configuration variable), then authentication is not attempted.
+
+--smtp-pass::
+	Password for SMTP-AUTH. The argument is optional: If no
+	argument is specified, then the empty string is used as
+	the password.
++
+In place of this option, the following configuration variables
+can be specified:
++
+--
+		* sendemail.smtppass
+		* sendemail.<identity>.smtppass (see sendemail.identity).
+--
++
+However, --smtp-pass always overrides these variables.
++
+Furthermore, passwords need not be specified in configuration files
+or on the command line. If a username has been specified (with
+--smtp-user or a configuration variable), but no password has been
+specified (with --smtp-pass or a configuration variable), then the
+user is prompted for a password while the input is masked for privacy.
 
 --smtp-ssl::
 	If set, connects to the SMTP server using SSL.
diff --git a/git-send-email.perl b/git-send-email.perl
index a1a9d14b00..fec55ea2df 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -157,7 +157,7 @@ my $compose_filename = ".msg.$$";
 
 # Variables we fill in automatically, or via prompting:
 my (@to,@cc,@initial_cc,@bcclist,@xh,
-	$initial_reply_to,$initial_subject,@files,$author,$sender,$compose,$time);
+	$initial_reply_to,$initial_subject,@files,$author,$sender,$smtp_authpass,$compose,$time);
 
 my $envelope_sender;
 
@@ -177,7 +177,7 @@ my ($quiet, $dry_run) = (0, 0);
 
 # Variables with corresponding config settings
 my ($thread, $chain_reply_to, $suppress_from, $signed_off_cc, $cc_cmd);
-my ($smtp_server, $smtp_server_port, $smtp_authuser, $smtp_authpass, $smtp_ssl);
+my ($smtp_server, $smtp_server_port, $smtp_authuser, $smtp_ssl);
 my ($identity, $aliasfiletype, @alias_files, @smtp_host_parts);
 my ($no_validate);
 
@@ -214,7 +214,7 @@ my $rc = GetOptions("sender|from=s" => \$sender,
 		    "smtp-server=s" => \$smtp_server,
 		    "smtp-server-port=s" => \$smtp_server_port,
 		    "smtp-user=s" => \$smtp_authuser,
-		    "smtp-pass=s" => \$smtp_authpass,
+		    "smtp-pass:s" => \$smtp_authpass,
 		    "smtp-ssl!" => \$smtp_ssl,
 		    "identity=s" => \$identity,
 		    "compose" => \$compose,
@@ -647,9 +647,26 @@ X-Mailer: git-send-email $gitversion
 			die "Unable to initialize SMTP properly.  Is there something wrong with your config?";
 		}
 
-		if ((defined $smtp_authuser) && (defined $smtp_authpass)) {
+		if (defined $smtp_authuser) {
+
+			if (!defined $smtp_authpass) {
+
+				system "stty -echo";
+
+				do {
+					print "Password: ";
+					$_ = <STDIN>;
+					print "\n";
+				} while (!defined $_);
+
+				chomp($smtp_authpass = $_);
+
+				system "stty echo";
+			}
+
 			$auth ||= $smtp->auth( $smtp_authuser, $smtp_authpass ) or die $smtp->message;
 		}
+
 		$smtp->mail( $raw_from ) or die $smtp->message;
 		$smtp->to( @recipients ) or die $smtp->message;
 		$smtp->data or die $smtp->message;