[PATCH common 05/21] systemd: move parse_os_release() helper to PVE::Systemd

[Shannon Sterz <s.sterz@proxmox.com>]

to avoid implementing such a parser multiple times.

Signed-off-by: Shannon Sterz <s.sterz@proxmox.com>
---
 src/PVE/Systemd.pm | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/PVE/Systemd.pm b/src/PVE/Systemd.pm
index 1ed5271..8a75ad3 100644
--- a/src/PVE/Systemd.pm
+++ b/src/PVE/Systemd.pm
@@ -365,4 +365,42 @@ sub notify {
     return;
 }
 
+=head3 parse_os_release()
+
+Allows parsing an C<os-release> file as defined by C<man 5 os-release>.
+
+=cut
+
+# os-release(5):
+#   (...) a newline-separated list of environment-like shell-compatible
+#   variable assignments. (...) beyond mere variable assignments, no shell
+#   features are supported (this means variable expansion is explicitly not
+#   supported) (...). Variable assignment values must be enclosed in double or
+#   single quotes *if* they include spaces, semicolons or other special
+#   characters outside of A-Z, a-z, 0-9. Shell special characters ("$", quotes,
+#   backslash, backtick) must be escaped with backslashes (...). All strings
+#   should be in UTF-8 format, and non-printable characters should not be used.
+#   It is not supported to concatenate multiple individually quoted strings.
+#   Lines beginning with "#" shall be ignored as comments.
+sub parse_os_release {
+    my ($data) = @_;
+    my $variables = {};
+    while (defined($data) && $data =~ /^(.+)$/gm) {
+        next if $1 !~ /^\s*([a-zA-Z_][a-zA-Z0-9_]*)=(.*)$/;
+        my ($var, $content) = ($1, $2);
+        chomp $content;
+
+        if ($content =~ /^'([^']*)'/) {
+            $variables->{$var} = $1;
+        } elsif ($content =~ /^"((?:[^"\\]|\\.)*)"/) {
+            my $s = $1;
+            $s =~ s/(\\["'`nt\$\\])/"\"$1\""/eeg;
+            $variables->{$var} = $s;
+        } elsif ($content =~ /^([A-Za-z0-9]*)/) {
+            $variables->{$var} = $1;
+        }
+    }
+    return $variables;
+}
+
 1;
-- 
2.47.3