[pass] [PATCH] Add support for displaying QR codes.

[Patrick Burroughs (Celti)]

This patch adds support for displaying passwords as QR codes for easy transfer
to any device that can read them, rendered in the terminal with ANSI escape
sequences via qrencode.

---
 man/pass.1            | 10 ++++++++--
 src/password-store.sh | 37 ++++++++++++++++++++++++-------------
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/man/pass.1 b/man/pass.1
index 8ac8ecf..4d44f8a 100644
--- a/man/pass.1
+++ b/man/pass.1
@@ -86,12 +86,15 @@ List names of passwords inside the tree that match \fIpass-names\fP by using the
 .BR tree (1)
 program. This command is alternatively named \fBsearch\fP.
 .TP
-\fBshow\fP [ \fI--clip\fP, \fI-c\fP ] \fIpass-name\fP
+\fBshow\fP [ \fI--clip\fP, \fI-c\fP | \fI--qr\fP, \fI-q\fP ] \fIpass-name\fP
 Decrypt and print a password named \fIpass-name\fP. If \fI--clip\fP or \fI-c\fP
 is specified, do not print the password but instead copy the first line to the
 clipboard using
 .BR xclip (1)
 and then restore the clipboard after 45 (or \fIPASSWORD_STORE_CLIP_TIME\fP) seconds.
+If \fI--qr\fP or \fI-q\fP is specified, do not print the password but instead display the first line as a QR code
+encoded using
+.BR qrencode (1).
 .TP
 \fBinsert\fP [ \fI--echo\fP, \fI-e\fP | \fI--multiline\fP, \fI-m\fP ] [ \fI--force\fP, \fI-f\fP ] \fIpass-name\fP
 Insert a new password into the password store called \fIpass-name\fP. This will
@@ -110,7 +113,7 @@ ensure that temporary files are created in \fI/dev/shm\fP in order to avoid writ
 difficult-to-erase disk sectors. If \fI/dev/shm\fP is not accessible, fallback to
 the ordinary \fITMPDIR\fP location, and print a warning.
 .TP
-\fBgenerate\fP [ \fI--no-symbols\fP, \fI-n\fP ] [ \fI--clip\fP, \fI-c\fP ] [ \fI--in-place\fP, \fI-i\fP | \fI--force\fP, \fI-f\fP ] \fIpass-name pass-length\fP
+\fBgenerate\fP [ \fI--no-symbols\fP, \fI-n\fP ] [ \fI--clip\fP, \fI-c\fP | \fI--qr\fP, \fI-q\fP ] [ \fI--in-place\fP, \fI-i\fP | \fI--force\fP, \fI-f\fP ] \fIpass-name pass-length\fP
 Generate a new password using
 .BR pwgen (1)
 of length \fIpass-length\fP and insert into \fIpass-name\fP. If \fI--no-symbols\fP or \fI-n\fP
@@ -119,6 +122,9 @@ If \fI--clip\fP or \fI-c\fP is specified, do not print the password but instead
 it to the clipboard using
 .BR xclip (1)
 and then restore the clipboard after 45 (or \fIPASSWORD_STORE_CLIP_TIME\fP) seconds.
+If \fI--qr\fP or \fI-q\fP is specified, do not print the password but instead display the first line as a QR code
+encoded using
+.BR qrencode (1).
 Prompt before overwriting an existing password,
 unless \fI--force\fP or \fI-f\fP is specified. If \fI--in-place\fP or \fI-i\fP is
 specified, do not interactively prompt, and only replace the first line of the password
diff --git a/src/password-store.sh b/src/password-store.sh
index e68384b..75b451b 100755
--- a/src/password-store.sh
+++ b/src/password-store.sh
@@ -126,7 +126,10 @@ check_sneaky_paths() {
 		[[ $path =~ /\.\.$ || $path =~ ^\.\./ || $path =~ /\.\./ || $path =~ ^\.\.$ ]] && die "Error: You've attempted to pass a sneaky path to pass. Go home."
 	done
 }
-
+qr_encode() {
+	echo "Displaying $2 as QR code."
+	echo -n "$1" | qrencode --8bit --type=ANSI
+}
 #
 # END helper functions
 #
@@ -222,8 +225,8 @@ cmd_usage() {
 	        List passwords.
 	    $PROGRAM find pass-names...
 	    	List passwords that match pass-names.
-	    $PROGRAM [show] [--clip,-c] pass-name
-	        Show existing password and optionally put it on the clipboard.
+	    $PROGRAM [show] [--clip,-c | --qr,-q] pass-name
+	        Show existing password and optionally put it on the clipboard or display it as a QR code.
 	        If put on the clipboard, it will be cleared in $CLIP_TIME seconds.
 	    $PROGRAM grep search-string
 	        Search for password files containing search-string when decrypted.
@@ -233,9 +236,9 @@ cmd_usage() {
 	        overwriting existing password unless forced.
 	    $PROGRAM edit pass-name
 	        Insert a new password or edit an existing password using ${EDITOR:-vi}.
-	    $PROGRAM generate [--no-symbols,-n] [--clip,-c] [--in-place,-i | --force,-f] pass-name pass-length
+	    $PROGRAM generate [--no-symbols,-n] [--clip,-c | --qr,-q] [--in-place,-i | --force,-f] pass-name pass-length
 	        Generate a new password of pass-length with optionally no symbols.
-	        Optionally put it on the clipboard and clear board after 45 seconds.
+	        Optionally put it on the clipboard and clear board after $CLIP_TIME seconds, or display it as a QR code.
 	        Prompt before overwriting existing password unless forced.
 	        Optionally replace only the first line of an existing file with a new password.
 	    $PROGRAM rm [--recursive,-r] [--force,-f] pass-name
@@ -294,27 +297,32 @@ cmd_init() {
 }
 
 cmd_show() {
-	local opts clip=0
-	opts="$($GETOPT -o c -l clip -n "$PROGRAM" -- "$@")"
+	local opts clip=0 qr=0
+	opts="$($GETOPT -o cq -l clip,qr -n "$PROGRAM" -- "$@")"
 	local err=$?
 	eval set -- "$opts"
 	while true; do case $1 in
 		-c|--clip) clip=1; shift ;;
+		-q|--qr) qr=1; shift ;;
 		--) shift; break ;;
 	esac done
 
-	[[ $err -ne 0 ]] && die "Usage: $PROGRAM $COMMAND [--clip,-c] [pass-name]"
+	[[ $err -ne 0 ]] && die "Usage: $PROGRAM $COMMAND [--clip,-c | --qr,-q] [pass-name]"
 
 	local path="$1"
 	local passfile="$PREFIX/$path.gpg"
 	check_sneaky_paths "$path"
 	if [[ -f $passfile ]]; then
-		if [[ $clip -eq 0 ]]; then
+		if [[ $clip -eq 0 && $qr -eq 0 ]]; then
 			exec $GPG -d "${GPG_OPTS[@]}" "$passfile"
 		else
 			local pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | head -n 1)"
 			[[ -n $pass ]] || exit 1
-			clip "$pass" "$path"
+			if [[ $clip -eq 1 ]]; then
+				clip "$pass" "$path"
+			elif [[ $qr -eq 1 ]]; then
+				qr_encode "$pass" "$path"
+			fi
 		fi
 	elif [[ -d $PREFIX/$path ]]; then
 		if [[ -z $path ]]; then
@@ -435,12 +443,13 @@ cmd_edit() {
 
 cmd_generate() {
 	local opts clip=0 force=0 symbols="-y" inplace=0
-	opts="$($GETOPT -o ncif -l no-symbols,clip,in-place,force -n "$PROGRAM" -- "$@")"
+	opts="$($GETOPT -o ncqif -l no-symbols,clip,qr,in-place,force -n "$PROGRAM" -- "$@")"
 	local err=$?
 	eval set -- "$opts"
 	while true; do case $1 in
 		-n|--no-symbols) symbols=""; shift ;;
 		-c|--clip) clip=1; shift ;;
+		-q|--qr) qr=1; shift ;;
 		-f|--force) force=1; shift ;;
 		-i|--in-place) inplace=1; shift ;;
 		--) shift; break ;;
@@ -474,10 +483,12 @@ cmd_generate() {
 	[[ $inplace -eq 1 ]] && verb="Replace"
 	git_add_file "$passfile" "$verb generated password for ${path}."
 
-	if [[ $clip -eq 0 ]]; then
+	if [[ $clip -eq 0 && $qr -eq 0 ]]; then
 		printf "\e[1m\e[37mThe generated password for \e[4m%s\e[24m is:\e[0m\n\e[1m\e[93m%s\e[0m\n" "$path" "$pass"
-	else
+	elif [[ $clip -eq 1 ]]; then
 		clip "$pass" "$path"
+	elif [[ $qr -eq 1 ]]; then
+		qr_encode "$pass" "$path"
 	fi
 }
 
-- 
2.0.0