1 files changed, 46 insertions, 34 deletions
diff --git a/bin/apf b/bin/apf
index 06f7aa6b..956142fe 100755
--- a/bin/apf
+++ b/bin/apf
@@ -1,43 +1,55 @@
-#!/usr/bin/env bash
-# Prepend arguments from a file to a command call
+#!/bin/sh
+# Prepend arguments from a file to the given arguments for a command
 self=apf
 
-# Require at least two arguments, give usage otherwise
-if (($# < 2)) ; then
-    printf '%s: usage: %s ARGFILE COMMAND [ARGS...]\n' \
-        "$self" "$self" >&2
+# Require at least two arguments
+if [ "$#" -lt 2 ] ; then
+    printf >&2 '%s: Need an arguments file and a command\n' "$self"
     exit 2
 fi
 
 # First argument is the file containing the null-delimited arguments
-argfile=$1
-shift
-
-# Check the arguments file makes sense
-if [[ ! -e $argfile ]] ; then
-    printf '%s: %s: No such file or directory\n' \
-        "$self" "$argfile"
-    exit 1
-elif [[ -d $argfile ]] ; then
-    printf '%s: %s: Is a directory\n' \
-        "$self" "$argfile"
-    exit 1
-elif [[ ! -r $argfile ]] ; then
-    printf '%s: %s: Permission denied\n' \
-        "$self" "$argfile"
-    exit 1
-fi
+argf=$1 cmd=$2
+shift 2
+
+# If the file exists, we'll read it. If it doesn't, this is not an error (think
+# personal config files like ~/.vimrc)
+if [ -f "$argf" ] ; then
+
+    # Create a temporary directory with name in $td, and handle POSIX-ish traps to
+    # remove it when the script exits.
+    td=
+    cleanup() {
+        [ -n "$td" ] && rm -fr -- "$td"
+        if [ "$1" != EXIT ] ; then
+            trap - "$1"
+            kill "-$1" "$$"
+        fi
+    }
+    for sig in EXIT HUP INT TERM ; do
+        # shellcheck disable=SC2064
+        trap "cleanup $sig" "$sig"
+    done
+    td=$(mktd "$self") || exit
 
-# Read all the null-delimited arguments from the file
-declare -a args
-while IFS= read -rd '' arg ; do
-    args[${#args[@]}]=$arg
-done < "$argfile"
+    # Write the arguments in reverse to a temporary file
+    revf=$td/revf
+    sed '1!G;$!{h;d}' "$argf" > "$revf" || exit
 
-# Next argument is the command to run
-cmd=$1
-shift
+    # Stack up all the arguments from the file. Skip blank lines and comments.
+    # An empty file is also fine.
+    while IFS= read -r arg ; do
+        case $arg in
+            '#'*) continue ;;
+            *[![:space:]]*) ;;
+            *) continue ;;
+        esac
+        set -- "$arg" "$@"
+    done < "$revf"
+
+    # We can remove the temporary stuff now, which allows us to exec safely
+    cleanup
+fi
 
-# Run the command with the retrieved arguments first, then the rest of the
-# command line as passed to the function
-command "$cmd" "${args[@]}" "$@"
+# Run the command with the changed arguments
+exec "$cmd" "$@"