[devtools/sigparse] Enhance it to make a report

Hm OSH still differs from many shells

devtools/sigparse.sh

@@ -6,21 +6,65 @@
 # https://unix.stackexchange.com/questions/85364/how-can-i-check-what-signals-a-process-is-listening-to
 #
 # Usage:
-#   ./sigparse.sh PID
-
-sigparse () {
-    i=0
-    # bits="$(printf "16i 2o %X p" "0x$1" | dc)" # variant for busybox
-    bits="$(printf "ibase=16; obase=2; %X\n" "0x$1" | bc)"
-    while [ -n "$bits" ] ; do
-        i="$(expr "$i" + 1)"
-        case "$bits" in
-            *1) printf " %s(%s)" "$(kill -l "$i")" "$i" ;;
-        esac
-        bits="${bits%?}"
-    done
+#   devtools/sigparse.sh <function name>
+
+sigparse() {
+  local i=0
+
+  # bits="$(printf "16i 2o %X p" "0x$1" | dc)" # variant for busybox
+
+  # hex to binary.  Could also do this with Python.
+  bits="$(printf "ibase=16; obase=2; %X\n" "0x$1" | bc)"
+  while test -n "$bits"; do
+    i=$((i + 1))
+    case "$bits" in
+      *1)
+        local sig_name=$(kill -l "$i")
+        printf ' %s(%s)' "$sig_name" "$i"
+        ;;
+    esac
+    bits="${bits%?}"
+  done
+}
+
+report() {
+  grep '^Sig...:' "/proc/$1/status" | while read state hex_mask; do
+    printf "%s%s\n" "$state" "$(sigparse "$hex_mask")"
+  done
+}
+
+compare-shells() {
+  local -a shells=(bash dash mksh zsh osh)
+
+  # Hm non-interactive shells have consistency.
+  # SIGCHLD and SIGINT are caught in bash, dash, zsh, mksh.  mksh catches
+  # several more.
+
+  for sh in ${shells[@]}; do
+    echo
+    echo "---- $sh ----"
+    echo
+
+    $sh -c 'script=$1; $script report $$' -- $0
+  done
+
+  echo
+  echo
+
+  for sh in ${shells[@]}; do
+    echo
+    echo "---- $sh -i ----"
+    echo
+
+    # Why does this cause 'stopped' ???  A stray signal.  Similar to spec test
+    # problems.
+    if test $sh = 'osh'; then
+      echo 'SKIPPING INTERACTIVE OSH (TODO: fix)'
+      continue
+    fi
+
+    $sh -i -c 'script=$1; $script report $$' -- $0
+  done
 }
 
-grep "^Sig...:" "/proc/$1/status" | while read a b ; do
-        printf "%s%s\n" "$a" "$(sigparse "$b")"
-    done # | fmt -t  # uncomment for pretty-printing
+"$@"