hstow: reduce number of ls(1), dirname(1), rm(1) and rmdir(1) calls

Also improve comment: 'xargs readlink' can be used like 'xargs ls -ld'.

1 files changed, 42 insertions, 0 deletions

diff --git a/lib-src/posix-defuns.sh b/lib-src/posix-defuns.sh
new file mode 100644
index 00000000..edacea49
--- /dev/null
+++ b/lib-src/posix-defuns.sh
@@ -0,0 +1,42 @@
+# POSIX sh-compatible shell functions
+#
+# Copyright (C) 2021, 2023  Sean Whitton <spwhitton@spwhitton.name>
+#
+# 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 3 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/>.
+
+# Copied from src/connection.lisp in Consfigurator, which see for commentary.
+mkstemp () {
+    local template="${1:-${TMPDIR:-/tmp}/tmp.XXXXXX}" err=
+    # Use a subshell in case the parent script is using the third file
+    # descriptor and to avoid changing its umask, though chances are we were
+    # called in a subshell, e.g. "$(mkstemp)", anyway.
+    ( umask 077
+      exec 3>&1
+      if err="$(if command -v m4 >/dev/null; then
+		    echo "mkstemp($template)" | m4 2>&1 1>&3
+		else
+		    mktemp "$template" 2>&1 1>&3
+		fi)"; then
+	  case "$err" in
+	      ?*) printf >&2 "%s\n" "$err"; exit 1 ;;
+	      *)  exit 0 ;;
+	  esac
+      else
+	  case "$err" in
+	      ?*) printf >&2 "%s\n" "$err" ;;
+	  esac
+	  exit 1
+      fi
+    )
+}