From 23576d58fb6c789d5e6daaeaecae88dade7122a4 Mon Sep 17 00:00:00 2001
From: Leonid Pliushch <sylirre@gmail.com>
Date: Sun, 7 Aug 2022 20:14:04 +0300
Subject: [PATCH 1/3] scripts: add option to suppress read failures for
 termux-backup

In certain cases $PREFIX may contain files that can't be read, but it
is acceptable to drop them from backup. The newly added option allows
to suppress read permission errors reported by tar.
---
 scripts/termux-backup.in | 75 ++++++++++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 22 deletions(-)

diff --git a/scripts/termux-backup.in b/scripts/termux-backup.in
index abcd1c9..8dd9bca 100644
--- a/scripts/termux-backup.in
+++ b/scripts/termux-backup.in
@@ -39,55 +39,86 @@ msg() {
 
 show_usage() {
 	msg
-	msg "Usage: termux-backup [output file]"
+	msg "Usage: termux-backup [options] [output file]"
 	msg
 	msg "Script for backing up Termux installation directory, \$PREFIX."
 	msg "It WILL NOT backup your home directory."
 	msg
+	msg "Options:"
+	msg
+	msg " -h, --help             Show this information."
+	msg " --ignore-read-failure  Suppress read permission denials."
+	msg
 	msg "Backup is performed as TAR archive. Compression is determined"
 	msg "by output file extension. If file name is '-', then tarball is"
 	msg "written to stdout and is uncompressed."
 	msg
 }
 
-if [ $# -lt 1 ]; then
-	msg
-	msg "[!] Output file path is not specified."
-	show_usage
+if [ ! -d "$PREFIX" ]; then
+	msg "[!] $PREFIX: directory does not exist."
 	exit 1
 fi
 
-if [ $# -gt 1 ]; then
-	shift 1
+if [ $# -lt 1 ]; then
 	msg
-	msg "[!] Got extra arguments: $*"
+	msg "[!] Not enough arguments."
 	show_usage
 	exit 1
 fi
 
-if [ ! -d "$PREFIX" ]; then
-	msg "[!] $PREFIX: directory does not exist."
-	exit 1
-fi
+BACKUP_FILE_PATH=
+TAR_EXTRA_OPTS=
+while (($# >= 1)); do
+	case "$1" in
+		--) shift 1; break;;
+		-\?|-h|--help|--usage)
+			show_usage
+			exit 0
+			;;
+		--ignore-read-failure)
+			TAR_EXTRA_OPTS="--ignore-failed-read --warning=no-failed-read"
+			;;
+		*)
+			if [ -z "$1" ]; then
+				msg
+				msg "[!] Backup file path should not be an empty string."
+				show_usage
+				exit 1
+			fi
+
+			# Filter all previously unrecognized options except '-', which is
+			# a valid backup output specification.
+			if [[ $1 =~ ^-.+ ]]; then
+				msg
+				msg "[!] Unknown option passed: ${1}"
+				show_usage
+				exit 1
+			fi
 
-case "$1" in
-	-\?|-h|--help|--usage) show_usage; exit 0;;
-	*) BACKUP_FILE_PATH=$1;;
-esac
+			if [ -z "$BACKUP_FILE_PATH" ]; then
+				BACKUP_FILE_PATH=$1
+			else
+				msg
+				msg "[!] Redundant backup file path specified: ${1}"
+				show_usage
+				exit 1
+			fi
+			;;
+	esac
+	shift 1
+done
 
 if [ "$BACKUP_FILE_PATH" != "-" ]; then
-	CAN_AUTOCOMPRESS=yes
+	TAR_EXTRA_OPTS="$TAR_EXTRA_OPTS --auto-compress"
 	if [ -e "$BACKUP_FILE_PATH" ]; then
 		msg
 		msg "[!] Refusing to overwrite already existing file '$BACKUP_FILE_PATH'."
 		msg
 		exit 1
 	fi
-else
-	CAN_AUTOCOMPRESS=
 fi
 
 msg "Backing up installed packages..."
-tar --warning=no-file-ignored -f "$BACKUP_FILE_PATH" \
-	-c ${CAN_AUTOCOMPRESS+--auto-compress} \
-	-C "@TERMUX_BASE_DIR@" ./usr
+tar --warning=no-file-ignored $TAR_EXTRA_OPTS -c \
+	-f "$BACKUP_FILE_PATH" -C "@TERMUX_BASE_DIR@" ./usr

From bff189fcccfdb572d763ceed790fdc809b00f7bb Mon Sep 17 00:00:00 2001
From: Leonid Pliushch <sylirre@gmail.com>
Date: Sun, 7 Aug 2022 20:18:39 +0300
Subject: [PATCH 2/3] scripts: detect when termux-backup is writing data to
 console

---
 scripts/termux-backup.in | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/termux-backup.in b/scripts/termux-backup.in
index 8dd9bca..3fab9b0 100644
--- a/scripts/termux-backup.in
+++ b/scripts/termux-backup.in
@@ -117,6 +117,13 @@ if [ "$BACKUP_FILE_PATH" != "-" ]; then
 		msg
 		exit 1
 	fi
+else
+	if [ -t 1 ]; then
+		msg
+		msg "[!] Refusing to write archive data to console."
+		msg
+		exit 1
+	fi
 fi
 
 msg "Backing up installed packages..."

From effe7e519470e9425b941fb50cb9683db5202a43 Mon Sep 17 00:00:00 2001
From: Leonid Pliushch <sylirre@gmail.com>
Date: Sun, 7 Aug 2022 20:34:49 +0300
Subject: [PATCH 3/3] scripts: add termux-backup option to allow overwrites

---
 scripts/termux-backup.in | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/scripts/termux-backup.in b/scripts/termux-backup.in
index 3fab9b0..54d54a0 100644
--- a/scripts/termux-backup.in
+++ b/scripts/termux-backup.in
@@ -47,6 +47,7 @@ show_usage() {
 	msg "Options:"
 	msg
 	msg " -h, --help             Show this information."
+	msg " -f, --force            Force write operations."
 	msg " --ignore-read-failure  Suppress read permission denials."
 	msg
 	msg "Backup is performed as TAR archive. Compression is determined"
@@ -69,6 +70,7 @@ fi
 
 BACKUP_FILE_PATH=
 TAR_EXTRA_OPTS=
+FORCE_WRITE=false
 while (($# >= 1)); do
 	case "$1" in
 		--) shift 1; break;;
@@ -76,6 +78,9 @@ while (($# >= 1)); do
 			show_usage
 			exit 0
 			;;
+		-f|--force)
+			FORCE_WRITE=true
+			;;
 		--ignore-read-failure)
 			TAR_EXTRA_OPTS="--ignore-failed-read --warning=no-failed-read"
 			;;
@@ -111,9 +116,9 @@ done
 
 if [ "$BACKUP_FILE_PATH" != "-" ]; then
 	TAR_EXTRA_OPTS="$TAR_EXTRA_OPTS --auto-compress"
-	if [ -e "$BACKUP_FILE_PATH" ]; then
+	if [ -e "$BACKUP_FILE_PATH" ] && ! $FORCE_WRITE; then
 		msg
-		msg "[!] Refusing to overwrite already existing file '$BACKUP_FILE_PATH'."
+		msg "[!] Refusing to overwrite existing file without --force option: '$BACKUP_FILE_PATH'."
 		msg
 		exit 1
 	fi