2 files changed, 149 insertions, 46 deletions

diff --git a/hyper/process/main.go b/hyper/process/main.go
index 5420f681..214dade9 100644
--- a/hyper/process/main.go
+++ b/hyper/process/main.go
@@ -10,68 +10,68 @@ import "bytes"
 
 import "hyper/process"
 
-var proc = map[string] *hyper.Process{}
+var proc = map[string]*hyper.Process{}
 
 // TODO Retrieve Process, Write, Kill [autokill], get exit code
 
 func RespondJSON(res http.ResponseWriter, v interface{}) os.Error {
-  content, err := json.Marshal(v)
-  if err == nil {
-    log.Printf("< %s", content)
-    res.Header().Set("Content-Type", "application/json; charset=\"utf-8\"")
-    res.WriteHeader(http.StatusOK)
-    res.Write(content)
-  } else {
-    log.Printf("%s while json.Marshal(%s)", err, v)
-  }
-  return err
+	content, err := json.Marshal(v)
+	if err == nil {
+		log.Printf("< %s", content)
+		res.Header().Set("Content-Type", "application/json; charset=\"utf-8\"")
+		res.WriteHeader(http.StatusOK)
+		res.Write(content)
+	} else {
+		log.Printf("%s while json.Marshal(%s)", err, v)
+	}
+	return err
 }
 
 func CreateProcessHandler(res http.ResponseWriter, req *http.Request) {
-  if p, err := hyper.NewProcess(req); err == nil {
-    id := p.Id()
-    proc[id] = p
-    RespondJSON(res, &map[string]string{
-      "path": fmt.Sprintf("/proc/%s", id),
-    })
-  } else {
-    log.Printf("%s", err)
-    res.WriteHeader(http.StatusInternalServerError)
-  }
+	if p, err := hyper.NewProcess(req); err == nil {
+		id := p.Id()
+		proc[id] = p
+		RespondJSON(res, &map[string]string{
+			"path": fmt.Sprintf("/proc/%s", id),
+		})
+	} else {
+		log.Printf("%s", err)
+		res.WriteHeader(http.StatusInternalServerError)
+	}
 }
 
 func RetrieveProcess(res http.ResponseWriter, req *http.Request) {
-  if p := proc[mux.Vars(req)["id"]]; p != nil {
-    RespondJSON(res, p)
-  } else {
-    res.WriteHeader(http.StatusNotFound)
-  }
+	if p := proc[mux.Vars(req)["id"]]; p != nil {
+		RespondJSON(res, p)
+	} else {
+		res.WriteHeader(http.StatusNotFound)
+	}
 }
 
 func FeedProcess(res http.ResponseWriter, req *http.Request) {
-  if p := proc[mux.Vars(req)["id"]]; p != nil {
-    body := make([]byte, 4096)
-    if _, err := req.Body.Read(body); err == nil {
-      body = bytes.TrimRight(body, string([]byte{0}))
-      p.Write(body)
-      //if err := p.Write(body); err == nil {
-        RespondJSON(res, true)
-      //}
-    }
-  } else {
-    res.WriteHeader(http.StatusNotFound)
-  }
+	if p := proc[mux.Vars(req)["id"]]; p != nil {
+		body := make([]byte, 4096)
+		if _, err := req.Body.Read(body); err == nil {
+			body = bytes.TrimRight(body, string([]byte{0}))
+			p.Write(body)
+			//if err := p.Write(body); err == nil {
+			RespondJSON(res, true)
+			//}
+		}
+	} else {
+		res.WriteHeader(http.StatusNotFound)
+	}
 }
 
 func main() {
 
-  // Gorilla
-  mux.HandleFunc("/proc", CreateProcessHandler).Methods("POST")
-  mux.HandleFunc("/proc/{id}", RetrieveProcess).Methods("GET")
-  mux.HandleFunc("/proc/{id}", FeedProcess).Methods("POST")
+	// Gorilla
+	mux.HandleFunc("/proc", CreateProcessHandler).Methods("POST")
+	mux.HandleFunc("/proc/{id}", RetrieveProcess).Methods("GET")
+	mux.HandleFunc("/proc/{id}", FeedProcess).Methods("POST")
 
-  err := http.ListenAndServe("0.0.0.0:8888", mux.DefaultRouter)
-  if err != nil {
-    log.Fatal("ListenAndServe: ", err.String())
-  }
+	err := http.ListenAndServe("0.0.0.0:8888", mux.DefaultRouter)
+	if err != nil {
+		log.Fatal("ListenAndServe: ", err.String())
+	}
 }
diff --git a/hyper/process/spawn b/hyper/process/spawn
new file mode 100755
index 00000000..65e94d86
--- /dev/null
+++ b/hyper/process/spawn
@@ -0,0 +1,103 @@
+#! /bin/sh
+#
+# [sh -x] spawn [command [argument ...]]
+#
+# export id to create&destroy or reuse the working directory //proc/$id/.
+# this feature is for debug only and marked as deprecated, so don't rely
+# on it too hard.
+#
+spawn() {
+  set -euf
+
+  # establish working subdirectory in //proc.  we're mking only
+  # transient dirs, i.e. if we mkdir, then we also defer rmdir.
+  if test -n "${id-}"; then
+    : "using id=$id from env"
+    wd=$pd/$id
+    if ! test -d $wd; then
+      : "make transient $wd/"
+      mkdir $wd
+      defer rmdir $wd
+    elif ! test `ls $wd | wc -l` = 0; then
+      : "$wd/ is not empty!"
+      exit 23
+    else
+      : "reuse existing $wd/"
+    fi
+  else
+    id=`cd $pd && mktemp -d XXXXXXXXXXXXXXXX`
+    wd=$pd/$id
+    defer rmdir $wd
+    : "made transient $wd/"
+  fi
+
+  # change to //proc working directory
+  cwd="$PWD"
+  cd $wd
+  defer cd $cwd
+
+  # create named pipes for the child process's stdio
+  mkfifo 0 1 2
+  defer rm 0 1 2
+
+  # spawn child process
+  ( : "in $PWD/ spawn ${*:-nothing}"
+    set +x # disable debug output so we don't clobber 2
+    exec 0>&- 1>&- 2>&- 0<>0 1<>1 2<>2
+    cd "$cwd"
+    exec "$@") &
+  pid=$!
+
+  # setup a trap to kill the child process if this (parent) process dies
+  defer kill $pid
+
+  # store misc. info.
+  ln -snf $cwd cwd
+  echo $id >id
+  echo $$ >ppid
+  echo $pid >pid
+  defer rm cwd id pid ppid
+
+  # wait for the child process's 
+  set +e
+  wait $pid
+  code=$?
+  set -e
+
+  # the child is already dead
+  cancel kill $pid
+
+  # return the same way wait did
+  (exit $code)
+}
+
+#
+# defer [command [argument ...]]
+#
+# Defer execution of a command.  Deferred commands are executed in LIFO
+# order immediately before the script terminates.  See (golang's defer
+# statement for more information how this should work).
+#
+defer() {
+  defer="$*${defer+
+$defer}"
+}
+
+#
+# cancel [command [argument ...]]
+#
+# Cancel a deferred command.  The arguments have to match exactly a
+# prior defer call or else chaos and mayhem shall haunt thee and shi-
+#
+cancel() {
+  defer="`echo "$defer" | grep -Fxv "$*"`"
+}
+
+# setup //proc directory
+pd=/tmp/krebs/proc
+mkdir -p $pd
+test -w $pd
+
+# setup deferred execution and spawn command
+trap 'eval "${defer-}"; defer=' EXIT INT TERM
+spawn "$@"