From 33ffa727b513afdd7cd4695ab37faf67ccd9d862 Mon Sep 17 00:00:00 2001
From: Stefan Schantl <stefan.schantl@ipfire.org>
Date: Fri, 15 Mar 2024 13:59:32 +0100
Subject: [PATCH] btrfs-functions.pl: New perl functions library

This library will contain functions to deal with BTRFS file systems.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
---
 config/cfgroot/btrfs-functions.pl | 136 ++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 config/cfgroot/btrfs-functions.pl

diff --git a/config/cfgroot/btrfs-functions.pl b/config/cfgroot/btrfs-functions.pl
new file mode 100644
index 000000000..acbb875a3
--- /dev/null
+++ b/config/cfgroot/btrfs-functions.pl
@@ -0,0 +1,136 @@
+#!/usr/bin/perl -w
+###############################################################################
+#                                                                             #
+# IPFire.org - A linux based firewall                                         #
+# Copyright (C) 2007-2024  IPFire Team  <info@ipfire.org>                     #
+#                                                                             #
+# This program is free software: you can redistribute it and/or modify        #
+# it under the terms of the GNU General Public License as published by        #
+# the Free Software Foundation, either version 2 of the License, or           #
+# (at your option) any later version.                                         #
+#                                                                             #
+# This program is distributed in the hope that it will be useful,             #
+# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
+# GNU General Public License for more details.                                #
+#                                                                             #
+# You should have received a copy of the GNU General Public License           #
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
+#                                                                             #
+###############################################################################
+
+package BTRFS;
+
+require '/var/ipfire/general-functions.pl';
+
+# Location where the btrfs binary lives.
+my $btrfs_bin = "/usr/bin/btrfs";
+
+#
+## Function to determine if a given mount path has an underlying BTRFS device.
+##
+## Example: is_btrfs("/")
+#
+sub is_btrfs($) {
+	my ($path) = @_;
+	
+	# Open and read-in the current mounts from the
+	# kernel file system.
+	open(MOUNT, "/proc/mounts");
+
+	# Read-in all currently mounted devices.
+	my @mounts = <MOUNT>;
+
+	# Close file handle.
+	close(MOUNT);
+
+	# Loop through the array of known mounts.
+	foreach my $mount (@mounts) {
+		# Skip mounts which does not belong to a device.
+		next unless ($mount =~ "^/dev");
+
+		# Cut the line into pieces and assign nice variables.
+		my ($dev, $mpoint, $fs, $options, $a, $b) = split(/ /, $mount);
+
+		# Skip lines until we found our given one.
+		next unless($path eq $mpoint);
+
+		# Check if the given path has a BTRFS file system.
+		if(($mpoint eq $path) && ($fs eq "btrfs")) {
+			# Requested path has a BTRFS as file system.
+			return 1;
+		}
+	}
+
+	# Requested path does not exist or does not contain a BTRFS.
+	return;
+}
+
+#
+## Function to get the proper free space of a given BTRFS formated device.
+##
+## Second argument: Output format in size or percent
+#
+sub free_space($$) {
+	my ($path, $format) = @_;
+
+	my $size;
+	my $free;
+
+	# Default to output in size (MB)
+	$format //= "size";
+
+	# Call the privata usage function.
+	my @usage = &_filesystem_usage($path);
+
+	# Loop through the output of the usage function.
+	foreach my $line (@usage) {
+		# Remove any newlines.
+		chomp($line);
+
+		# Split the output line into pieces.
+		my ($item, $value) = split(/:/, $line);
+
+		# Grab the total size of the filesystem.
+		if ($line =~/.*Device size:\s+(.*)MB/) {
+			$size = $1;
+
+		# Grab the available space.
+		} elsif ($line =~/.*Free.*estimated.*:\s+(.*)MB.*min:.*/) {
+			$free = $1;
+		}
+
+		# Break the loop in case the size and free space have been grabbed.
+		last if(($size) && ($free));
+	}
+
+	# Calculate the output in percent if requested.
+	if ($format eq "percent") {
+		my $free_percent = $free * 100 / $size;
+
+		# Return the free space in percent.
+		return sprintf("%.2f", $free_percent);
+	}
+
+	# Return the free space in MB.
+	return "$free";
+}
+
+#
+## Private subfunction which simply calls the filesystem usage of the btrfs tool.
+#
+sub _filesystem_usage($) {
+	my ($path) = @_;
+
+	# Abort if the given path does not exist or does not contain a BTRFS.
+	return unless(&is_btrfs($path));
+
+	# Call btrfs binary to get details about the current filesystem usage.
+	my @output = &General::system_output("$btrfs_bin", "filesystem", "usage", "--si", "-m", "$path");
+
+	# Return the grabbed output.
+	return @output;
+}
+
+
+1;
-- 
2.39.5