From 00daf2084335c764f16c8edac658f7ca3f121f87 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Wed, 28 Apr 2021 15:30:27 -0400
Subject: [PATCH 01/13] adds Process.exec(cmd, [args])

---
 src/cli/modules.c      |  2 ++
 src/module/os.c        | 56 ++++++++++++++++++++++++++++++++++++++++++
 src/module/os.h        |  7 ++++++
 src/module/os.wren     |  9 +++++++
 src/module/os.wren.inc |  9 +++++++
 5 files changed, 83 insertions(+)

diff --git a/src/cli/modules.c b/src/cli/modules.c
index a3c7f6c1..4e20cada 100644
--- a/src/cli/modules.c
+++ b/src/cli/modules.c
@@ -32,6 +32,7 @@ extern void processCwd(WrenVM* vm);
 extern void processPid(WrenVM* vm);
 extern void processPpid(WrenVM* vm);
 extern void processVersion(WrenVM* vm);
+extern void processExec(WrenVM* vm);
 extern void statPath(WrenVM* vm);
 extern void statBlockCount(WrenVM* vm);
 extern void statBlockSize(WrenVM* vm);
@@ -180,6 +181,7 @@ static ModuleRegistry modules[] =
       STATIC_METHOD("pid", processPid)
       STATIC_METHOD("ppid", processPpid)
       STATIC_METHOD("version", processVersion)
+      STATIC_METHOD("exec_(_,_,_)", processExec)
     END_CLASS
   END_MODULE
   MODULE(repl)
diff --git a/src/module/os.c b/src/module/os.c
index c13cd33f..14d9144d 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -1,6 +1,9 @@
 #include "os.h"
 #include "uv.h"
 #include "wren.h"
+#include "vm.h"
+#include "scheduler.h"
+#include <inttypes.h>
 
 #if __APPLE__
   #include "TargetConditionals.h"
@@ -128,3 +131,56 @@ void processVersion(WrenVM* vm) {
   wrenEnsureSlots(vm, 1);
   wrenSetSlotString(vm, 0, WREN_VERSION_STRING);
 }
+
+void proccesOnExit(uv_process_t *req, int64_t exit_status, int term_signal) {
+    uv_close((uv_handle_t*) req, NULL);
+    schedulerResume(((processData*)req->data)->fiber, true);
+    wrenSetSlotDouble(getVM(), 2, exit_status);
+    schedulerFinishResume();
+
+    free((processData*)(req->data));
+    free(req);
+}
+
+void processExec(WrenVM* vm) {
+    uv_process_t *child_req = malloc(sizeof(uv_process_t));
+    processData* data = malloc(sizeof(processData));
+    memset(data, 0, sizeof(processData));
+
+    // 2 extra slots in args for:
+    //  - the program to execute (head)
+    //  - NULL terminator (tail)
+    const char* args[PROCESS_MAX_EXEC_ARGUMENTS + 2];
+    uv_loop_t *loop = getLoop();
+
+    args[0] = wrenGetSlotString(vm,1);
+    int argCount = wrenGetListCount(vm,2);
+    WrenHandle *fiber = wrenGetSlotHandle(vm,3);
+
+    // TODO: allocate args dynamically to remove this limitation?
+    if (argCount > PROCESS_MAX_EXEC_ARGUMENTS) {
+      wrenSetSlotString(vm, 0, "Too many process arguments.");
+      wrenAbortFiber(vm, 0);
+    }
+
+    wrenEnsureSlots(vm,4);
+    for (int i = 0; i < argCount; i++) {
+      wrenGetListElement(vm, 2, i, 4);
+      args[i+1] = wrenGetSlotString(vm,4);
+    }
+    args[argCount+1] = NULL;
+
+    data->options.exit_cb = proccesOnExit;
+    data->options.file = args[0];
+    data->options.args = args;
+
+    data->fiber = fiber;
+    child_req->data = data;
+
+    int r;
+    if ((r = uv_spawn(loop, child_req, &data->options))) {
+        fprintf(stderr, "could not launch %s, %s\n", args[0], uv_strerror(r));
+        wrenSetSlotString(vm, 0, "Could not spawn process.");
+        wrenAbortFiber(vm, 0);
+    }
+}
diff --git a/src/module/os.h b/src/module/os.h
index b9988f80..2f306d75 100644
--- a/src/module/os.h
+++ b/src/module/os.h
@@ -1,9 +1,16 @@
 #ifndef process_h
 #define process_h
 
+#include "uv.h"
 #include "wren.h"
 
 #define WREN_PATH_MAX 4096
+#define PROCESS_MAX_EXEC_ARGUMENTS 20
+
+typedef struct {
+  WrenHandle* fiber;
+  uv_process_options_t options;
+} processData;
 
 // Stores the command line arguments passed to the CLI.
 void osSetArguments(int argc, const char* argv[]);
diff --git a/src/module/os.wren b/src/module/os.wren
index 4d9ec25a..3c5c3ae7 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -1,3 +1,5 @@
+import "scheduler" for Scheduler
+
 class Platform {
   foreign static homePath
   foreign static isPosix
@@ -10,6 +12,13 @@ class Process {
   // TODO: This will need to be smarter when wren supports CLI options.
   static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }
 
+  // executes a command passing it the specified arguments (as a list)
+  static exec(cmd, argList) {
+    exec_(cmd, argList, Fiber.current)
+    return Scheduler.runNextScheduled_()
+  }
+
+  foreign static exec_(cmd, args, fiber)
   foreign static allArguments
   foreign static cwd
   foreign static pid
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index 8c7c8522..17d5b55d 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -2,6 +2,8 @@
 // from `src/module/os.wren` using `util/wren_to_c_string.py`
 
 static const char* osModuleSource =
+"import \"scheduler\" for Scheduler\n"
+"\n"
 "class Platform {\n"
 "  foreign static homePath\n"
 "  foreign static isPosix\n"
@@ -14,6 +16,13 @@ static const char* osModuleSource =
 "  // TODO: This will need to be smarter when wren supports CLI options.\n"
 "  static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }\n"
 "\n"
+"  // executes a command passing it the specified arguments (as a list)\n"
+"  static exec(cmd, argList) {\n"
+"    exec_(cmd, argList, Fiber.current)\n"
+"    return Scheduler.runNextScheduled_()\n"
+"  }\n"
+"\n"
+"  foreign static exec_(cmd, args, fiber)\n"
 "  foreign static allArguments\n"
 "  foreign static cwd\n"
 "  foreign static pid\n"

From c2a105f29eccf1922e2cdd176bc48ac09bcdf1fd Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Wed, 28 Apr 2021 15:53:33 -0400
Subject: [PATCH 02/13] cannot spell

---
 src/module/os.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/module/os.c b/src/module/os.c
index 14d9144d..765ad76b 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -132,7 +132,7 @@ void processVersion(WrenVM* vm) {
   wrenSetSlotString(vm, 0, WREN_VERSION_STRING);
 }
 
-void proccesOnExit(uv_process_t *req, int64_t exit_status, int term_signal) {
+void processOnExit(uv_process_t *req, int64_t exit_status, int term_signal) {
     uv_close((uv_handle_t*) req, NULL);
     schedulerResume(((processData*)req->data)->fiber, true);
     wrenSetSlotDouble(getVM(), 2, exit_status);
@@ -170,7 +170,7 @@ void processExec(WrenVM* vm) {
     }
     args[argCount+1] = NULL;
 
-    data->options.exit_cb = proccesOnExit;
+    data->options.exit_cb = processOnExit;
     data->options.file = args[0];
     data->options.args = args;
 

From ca045135436ec8346c9e7568f59cc472deb49136 Mon Sep 17 00:00:00 2001
From: ruby0x1 <ruby0x1@pm.me>
Date: Sun, 2 May 2021 14:33:27 -0700
Subject: [PATCH 03/13] refactor; fix ownership of strings, clean up the uv
 handle safely, add some todos

---
 src/cli/cli_common.h   |  24 ++++++++
 src/module/os.c        | 121 ++++++++++++++++++++++++-----------------
 src/module/os.h        |   3 +-
 src/module/os.wren     |   5 +-
 src/module/os.wren.inc |   5 +-
 5 files changed, 101 insertions(+), 57 deletions(-)
 create mode 100644 src/cli/cli_common.h

diff --git a/src/cli/cli_common.h b/src/cli/cli_common.h
new file mode 100644
index 00000000..1e7fe855
--- /dev/null
+++ b/src/cli/cli_common.h
@@ -0,0 +1,24 @@
+#ifndef cli_common_h
+#define cli_common_h
+
+#include <stdlib.h>
+#include <string.h>
+
+inline char* cli_strdup(const char* s) {
+  size_t len = strlen(s) + 1;
+  char* m = (char*)malloc(len);
+  if (m == NULL) return NULL;
+  return memcpy(m, s, len);
+}
+
+inline char* cli_strndup(const char* s, size_t n) {
+  char* m;
+  size_t len = strlen(s);
+  if (n < len) len = n;
+  m = (char*)malloc(len + 1);
+  if (m == NULL) return NULL;
+  m[len] = '\0';
+  return memcpy(m, s, len);
+}
+
+#endif
\ No newline at end of file
diff --git a/src/module/os.c b/src/module/os.c
index 765ad76b..f8f9b386 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -3,7 +3,9 @@
 #include "wren.h"
 #include "vm.h"
 #include "scheduler.h"
-#include <inttypes.h>
+#include "cli_common.h"
+
+#include <stdint.h>
 
 #if __APPLE__
   #include "TargetConditionals.h"
@@ -132,55 +134,76 @@ void processVersion(WrenVM* vm) {
   wrenSetSlotString(vm, 0, WREN_VERSION_STRING);
 }
 
-void processOnExit(uv_process_t *req, int64_t exit_status, int term_signal) {
-    uv_close((uv_handle_t*) req, NULL);
-    schedulerResume(((processData*)req->data)->fiber, true);
-    wrenSetSlotDouble(getVM(), 2, exit_status);
-    schedulerFinishResume();
+// Called when the UV handle for a process is done, so we can free it
+static void processOnClose(uv_handle_t* req) 
+{
+  free((void*)req);
+}
+
+// Called when a process is finished running
+static void processOnExit(uv_process_t* req, int64_t exit_status, int term_signal) 
+{
+  ProcessData* data = (ProcessData*)req->data;
+  WrenHandle* fiber = data->fiber;
+
+  uv_close((uv_handle_t*)req, processOnClose);
 
-    free((processData*)(req->data));
-    free(req);
+  int index = 0;
+  char* arg = data->options.args[index];
+  while (arg != NULL)
+  {
+    free(arg);
+    index += 1;
+    arg = data->options.args[index];
+  }
+
+  free((void*)data);
+
+  schedulerResume(fiber, true);
+  wrenSetSlotDouble(getVM(), 2, (double)exit_status);
+  schedulerFinishResume();
 }
 
-void processExec(WrenVM* vm) {
-    uv_process_t *child_req = malloc(sizeof(uv_process_t));
-    processData* data = malloc(sizeof(processData));
-    memset(data, 0, sizeof(processData));
-
-    // 2 extra slots in args for:
-    //  - the program to execute (head)
-    //  - NULL terminator (tail)
-    const char* args[PROCESS_MAX_EXEC_ARGUMENTS + 2];
-    uv_loop_t *loop = getLoop();
-
-    args[0] = wrenGetSlotString(vm,1);
-    int argCount = wrenGetListCount(vm,2);
-    WrenHandle *fiber = wrenGetSlotHandle(vm,3);
-
-    // TODO: allocate args dynamically to remove this limitation?
-    if (argCount > PROCESS_MAX_EXEC_ARGUMENTS) {
-      wrenSetSlotString(vm, 0, "Too many process arguments.");
-      wrenAbortFiber(vm, 0);
-    }
-
-    wrenEnsureSlots(vm,4);
-    for (int i = 0; i < argCount; i++) {
-      wrenGetListElement(vm, 2, i, 4);
-      args[i+1] = wrenGetSlotString(vm,4);
-    }
-    args[argCount+1] = NULL;
-
-    data->options.exit_cb = processOnExit;
-    data->options.file = args[0];
-    data->options.args = args;
-
-    data->fiber = fiber;
-    child_req->data = data;
-
-    int r;
-    if ((r = uv_spawn(loop, child_req, &data->options))) {
-        fprintf(stderr, "could not launch %s, %s\n", args[0], uv_strerror(r));
-        wrenSetSlotString(vm, 0, "Could not spawn process.");
-        wrenAbortFiber(vm, 0);
-    }
+void processExec(WrenVM* vm) 
+{
+  ProcessData* data = (ProcessData*)malloc(sizeof(ProcessData));
+  memset(data, 0, sizeof(ProcessData));
+
+  //:todo: add env + cwd + flags args
+
+  char* cmd = cli_strdup(wrenGetSlotString(vm, 1));
+
+  data->options.file = cmd;
+  data->options.exit_cb = processOnExit;
+  data->fiber = wrenGetSlotHandle(vm, 3);
+
+  int argCount = wrenGetListCount(vm, 2);
+  int argsSize = sizeof(char*) * (argCount + 2);
+    
+  // First argument is the cmd, last+1 is NULL
+  data->options.args = (char**)malloc(argsSize);
+  data->options.args[0] = cmd;
+  data->options.args[argCount + 1] = NULL;
+
+  wrenEnsureSlots(vm, 3);
+  for (int i = 0; i < argCount; i++) 
+  {
+    wrenGetListElement(vm, 2, i, 3);
+    //:todo: ensure this is a string, and report an error if not
+    char* arg = cli_strdup(wrenGetSlotString(vm, 3));
+    data->options.args[i + 1] = arg;
+  }
+
+  uv_process_t* child_req = (uv_process_t*)malloc(sizeof(uv_process_t));
+  memset(child_req, 0, sizeof(uv_process_t));
+
+  child_req->data = data;
+
+  int r;
+  if ((r = uv_spawn(getLoop(), child_req, &data->options))) 
+  {
+    fprintf(stderr, "Could not launch %s, reason: %s\n", cmd, uv_strerror(r));
+    wrenSetSlotString(vm, 0, "Could not spawn process.");
+    wrenAbortFiber(vm, 0);
+  }
 }
diff --git a/src/module/os.h b/src/module/os.h
index 2f306d75..55c8beed 100644
--- a/src/module/os.h
+++ b/src/module/os.h
@@ -5,12 +5,11 @@
 #include "wren.h"
 
 #define WREN_PATH_MAX 4096
-#define PROCESS_MAX_EXEC_ARGUMENTS 20
 
 typedef struct {
   WrenHandle* fiber;
   uv_process_options_t options;
-} processData;
+} ProcessData;
 
 // Stores the command line arguments passed to the CLI.
 void osSetArguments(int argc, const char* argv[]);
diff --git a/src/module/os.wren b/src/module/os.wren
index 3c5c3ae7..e076dda7 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -12,9 +12,8 @@ class Process {
   // TODO: This will need to be smarter when wren supports CLI options.
   static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }
 
-  // executes a command passing it the specified arguments (as a list)
-  static exec(cmd, argList) {
-    exec_(cmd, argList, Fiber.current)
+  static exec(cmd, args) {
+    exec_(cmd, args, Fiber.current)
     return Scheduler.runNextScheduled_()
   }
 
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index 17d5b55d..17ef658e 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -16,9 +16,8 @@ static const char* osModuleSource =
 "  // TODO: This will need to be smarter when wren supports CLI options.\n"
 "  static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }\n"
 "\n"
-"  // executes a command passing it the specified arguments (as a list)\n"
-"  static exec(cmd, argList) {\n"
-"    exec_(cmd, argList, Fiber.current)\n"
+"  static exec(cmd, args) {\n"
+"    exec_(cmd, args, Fiber.current)\n"
 "    return Scheduler.runNextScheduled_()\n"
 "  }\n"
 "\n"

From 2b74cd6769d19ce70ce32d024e8d595e38d8e9dc Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 18:43:20 -0400
Subject: [PATCH 04/13] more api

---
 src/cli/modules.c      |  2 +-
 src/module/os.c        |  2 +-
 src/module/os.wren     | 12 ++++++++++--
 src/module/os.wren.inc | 12 ++++++++++--
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/cli/modules.c b/src/cli/modules.c
index 4e20cada..f87a501c 100644
--- a/src/cli/modules.c
+++ b/src/cli/modules.c
@@ -181,7 +181,7 @@ static ModuleRegistry modules[] =
       STATIC_METHOD("pid", processPid)
       STATIC_METHOD("ppid", processPpid)
       STATIC_METHOD("version", processVersion)
-      STATIC_METHOD("exec_(_,_,_)", processExec)
+      STATIC_METHOD("exec_(_,_,_,_,_)", processExec)
     END_CLASS
   END_MODULE
   MODULE(repl)
diff --git a/src/module/os.c b/src/module/os.c
index f8f9b386..bd00be2a 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -175,7 +175,7 @@ void processExec(WrenVM* vm)
 
   data->options.file = cmd;
   data->options.exit_cb = processOnExit;
-  data->fiber = wrenGetSlotHandle(vm, 3);
+  data->fiber = wrenGetSlotHandle(vm, 5);
 
   int argCount = wrenGetListCount(vm, 2);
   int argsSize = sizeof(char*) * (argCount + 2);
diff --git a/src/module/os.wren b/src/module/os.wren
index e076dda7..8f0165e9 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -13,11 +13,19 @@ class Process {
   static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }
 
   static exec(cmd, args) {
-    exec_(cmd, args, Fiber.current)
+    return exec(cmd, args, null, null)
+  }
+
+  static exec(cmd, args, cwd) { 
+    return exec(cmd, args, cwd, null) 
+  }
+  
+  static exec(cmd, args, cwd, env) { 
+    exec_(cmd, args, cwd, env, Fiber.current)
     return Scheduler.runNextScheduled_()
   }
 
-  foreign static exec_(cmd, args, fiber)
+  foreign static exec_(cmd, args, cwd, env, fiber)
   foreign static allArguments
   foreign static cwd
   foreign static pid
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index 17ef658e..2c658f89 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -17,11 +17,19 @@ static const char* osModuleSource =
 "  static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }\n"
 "\n"
 "  static exec(cmd, args) {\n"
-"    exec_(cmd, args, Fiber.current)\n"
+"    return exec(cmd, args, null, null)\n"
+"  }\n"
+"\n"
+"  static exec(cmd, args, cwd) { \n"
+"    return exec(cmd, args, cwd, null) \n"
+"  }\n"
+"  \n"
+"  static exec(cmd, args, cwd, env) { \n"
+"    exec_(cmd, args, cwd, env, Fiber.current)\n"
 "    return Scheduler.runNextScheduled_()\n"
 "  }\n"
 "\n"
-"  foreign static exec_(cmd, args, fiber)\n"
+"  foreign static exec_(cmd, args, cwd, env, fiber)\n"
 "  foreign static allArguments\n"
 "  foreign static cwd\n"
 "  foreign static pid\n"

From aa2033682fd35a585f470dfe23884255ec0aef76 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 18:50:27 -0400
Subject: [PATCH 05/13] single exec

---
 src/module/os.wren     | 4 ++++
 src/module/os.wren.inc | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/module/os.wren b/src/module/os.wren
index 8f0165e9..942380cb 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -12,6 +12,10 @@ class Process {
   // TODO: This will need to be smarter when wren supports CLI options.
   static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }
 
+  static exec(cmd) {
+    return exec(cmd, [], null, null)
+  }
+
   static exec(cmd, args) {
     return exec(cmd, args, null, null)
   }
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index 2c658f89..bee24871 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -16,6 +16,10 @@ static const char* osModuleSource =
 "  // TODO: This will need to be smarter when wren supports CLI options.\n"
 "  static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }\n"
 "\n"
+"  static exec(cmd) {\n"
+"    return exec(cmd, [], null, null)\n"
+"  }\n"
+"\n"
 "  static exec(cmd, args) {\n"
 "    return exec(cmd, args, null, null)\n"
 "  }\n"

From 58c4a8ba90e58b1292f80fe8331ee2d36645a620 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 18:50:35 -0400
Subject: [PATCH 06/13] exec tests

---
 test/os/process/exec.wren | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 test/os/process/exec.wren

diff --git a/test/os/process/exec.wren b/test/os/process/exec.wren
new file mode 100644
index 00000000..03624769
--- /dev/null
+++ b/test/os/process/exec.wren
@@ -0,0 +1,22 @@
+import "os" for Platform, Process
+
+var result
+if(Platform.name == "Windows") {
+  result = Process.exec("cmd.exe", [])
+} else {
+  // works on Mac
+  result = Process.exec("/usr/bin/true", [])
+}
+System.print(result) // expect: 0
+
+if (Platform.isPosix) {
+  // known output of success/fail based on only command name
+  System.print(Process.exec("/usr/bin/true")) // expect: 0
+  System.print(Process.exec("/usr/bin/false")) // expect: 1
+  // these test that our arguments are being passed as it proves
+  // they effect the result code returned
+  System.print(Process.exec("/bin/test", ["2", "-eq", "2"])) // expect: 0
+  System.print(Process.exec("/bin/test", ["2", "-eq", "3"])) // expect: 1
+} else if (Platform.name == "Windows") {
+  // TODO: more windows argument specific tests
+}

From 5ca236733a92d3fabec23a42305e8faaabe07e06 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 18:57:08 -0400
Subject: [PATCH 07/13] cwd

---
 src/module/os.c           |  7 +++++++
 test/os/process/exec.wren | 13 +++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/src/module/os.c b/src/module/os.c
index bd00be2a..34c28d13 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -164,6 +164,8 @@ static void processOnExit(uv_process_t* req, int64_t exit_status, int term_signa
   schedulerFinishResume();
 }
 
+//        1     2    3    4     5
+// exec_(cmd, args, cwd, env, fiber)
 void processExec(WrenVM* vm) 
 {
   ProcessData* data = (ProcessData*)malloc(sizeof(ProcessData));
@@ -173,6 +175,11 @@ void processExec(WrenVM* vm)
 
   char* cmd = cli_strdup(wrenGetSlotString(vm, 1));
 
+  if (wrenGetSlotType(vm, 3) != WREN_TYPE_NULL) {
+    const char* cwd = wrenGetSlotString(vm, 3);
+    data->options.cwd = cwd;
+  }
+
   data->options.file = cmd;
   data->options.exit_cb = processOnExit;
   data->fiber = wrenGetSlotHandle(vm, 5);
diff --git a/test/os/process/exec.wren b/test/os/process/exec.wren
index 03624769..2956d6cf 100644
--- a/test/os/process/exec.wren
+++ b/test/os/process/exec.wren
@@ -9,6 +9,8 @@ if(Platform.name == "Windows") {
 }
 System.print(result) // expect: 0
 
+// basics
+
 if (Platform.isPosix) {
   // known output of success/fail based on only command name
   System.print(Process.exec("/usr/bin/true")) // expect: 0
@@ -20,3 +22,14 @@ if (Platform.isPosix) {
 } else if (Platform.name == "Windows") {
   // TODO: more windows argument specific tests
 }
+
+// cwd
+
+if (Platform.isPosix) {
+  // tests exists in our root
+  System.print(Process.exec("ls", ["test"])) // expect: 0
+  // but not in our `src` folder
+  System.print(Process.exec("ls", ["test"], "./src/")) // expect: 1
+} else if (Platform.name == "Windows") {
+  // TODO: can this be done with dir on windows?
+}
\ No newline at end of file

From 3384115bcb42684a3446993ff2c354c6404ff690 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 20:09:16 -0400
Subject: [PATCH 08/13] env

---
 src/module/os.c           | 50 +++++++++++++++++++++++++++++++++++++--
 src/module/os.wren        | 12 +++++++++-
 src/module/os.wren.inc    | 12 +++++++++-
 test/os/process/exec.wren | 16 +++++++++++++
 4 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/src/module/os.c b/src/module/os.c
index 34c28d13..2f45a749 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -157,6 +157,17 @@ static void processOnExit(uv_process_t* req, int64_t exit_status, int term_signa
     arg = data->options.args[index];
   }
 
+  index = 0;
+  if (data->options.env) {
+    char* env = data->options.env[index];
+    while (env != NULL)
+    {
+      free(env);
+      index += 1;
+      env = data->options.args[index];
+    }
+  }
+
   free((void*)data);
 
   schedulerResume(fiber, true);
@@ -184,6 +195,41 @@ void processExec(WrenVM* vm)
   data->options.exit_cb = processOnExit;
   data->fiber = wrenGetSlotHandle(vm, 5);
 
+  wrenEnsureSlots(vm, 6);
+
+  if (wrenGetSlotType(vm, 4) == WREN_TYPE_NULL) {
+    // no environment specified
+  } else if (wrenGetSlotType(vm, 4) == WREN_TYPE_LIST) {
+    // fprintf(stderr,"got list\n");
+    int envCount = wrenGetListCount(vm, 4);
+    int envSize = sizeof(char*) * (envCount + 1);
+
+    data->options.env = (char**)malloc(envSize);
+    data->options.env[envCount] = NULL;
+
+    // fprintf(stderr,"envsize %d\n", envCount);
+    for (int i = 0; i < envCount ; i++) 
+    {
+      
+      wrenGetListElement(vm, 4, i, 6);
+      //:todo: ensure this is a string, and report an error if not
+
+      if (wrenGetSlotType(vm, 6) != WREN_TYPE_STRING) {
+        wrenSetSlotString(vm, 0, "aruments to params are suppose to be string");
+        wrenAbortFiber(vm, 0);        
+      }
+      char* envKeyPlusValue = cli_strdup(wrenGetSlotString(vm, 6));
+      // fprintf(stderr,"key: %s\n", envKeyPlusValue);
+      // fprintf(stderr,"setting %s\n", envKeyPlusValue);
+      // char* equalSplit = strchr(envKeyPlusValue, '=');
+      // *equalSplit = '\0';
+      // char* key = envKeyPlusValue;
+      // char* value = equalSplit + 1;
+
+      data->options.env[i] = envKeyPlusValue;
+    }
+  }
+
   int argCount = wrenGetListCount(vm, 2);
   int argsSize = sizeof(char*) * (argCount + 2);
     
@@ -192,7 +238,6 @@ void processExec(WrenVM* vm)
   data->options.args[0] = cmd;
   data->options.args[argCount + 1] = NULL;
 
-  wrenEnsureSlots(vm, 3);
   for (int i = 0; i < argCount; i++) 
   {
     wrenGetListElement(vm, 2, i, 3);
@@ -209,7 +254,8 @@ void processExec(WrenVM* vm)
   int r;
   if ((r = uv_spawn(getLoop(), child_req, &data->options))) 
   {
-    fprintf(stderr, "Could not launch %s, reason: %s\n", cmd, uv_strerror(r));
+    // should be stderr??? but no idea how to make tests work/pass with that
+    fprintf(stdout, "Could not launch %s, reason: %s\n", cmd, uv_strerror(r));
     wrenSetSlotString(vm, 0, "Could not spawn process.");
     wrenAbortFiber(vm, 0);
   }
diff --git a/src/module/os.wren b/src/module/os.wren
index 942380cb..eec8d92a 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -24,7 +24,17 @@ class Process {
     return exec(cmd, args, cwd, null) 
   }
   
-  static exec(cmd, args, cwd, env) { 
+  static exec(cmd, args, cwd, envMap) { 
+    var env = []
+    if (envMap is Map) {
+      for (entry in envMap) {
+        env.add([entry.key, entry.value].join("="))
+      }
+    } else if (envMap == null) {
+      env = null
+    } else {
+      Fiber.abort("environment vars must be passed as a Map")
+    }
     exec_(cmd, args, cwd, env, Fiber.current)
     return Scheduler.runNextScheduled_()
   }
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index bee24871..42f2955d 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -28,7 +28,17 @@ static const char* osModuleSource =
 "    return exec(cmd, args, cwd, null) \n"
 "  }\n"
 "  \n"
-"  static exec(cmd, args, cwd, env) { \n"
+"  static exec(cmd, args, cwd, envMap) { \n"
+"    var env = []\n"
+"    if (envMap is Map) {\n"
+"      for (entry in envMap) {\n"
+"        env.add([entry.key, entry.value].join(\"=\"))\n"
+"      }\n"
+"    } else if (envMap == null) {\n"
+"      env = null\n"
+"    } else {\n"
+"      Fiber.abort(\"environment vars must be passed as a Map\")\n"
+"    }\n"
 "    exec_(cmd, args, cwd, env, Fiber.current)\n"
 "    return Scheduler.runNextScheduled_()\n"
 "  }\n"
diff --git a/test/os/process/exec.wren b/test/os/process/exec.wren
index 2956d6cf..620e80f8 100644
--- a/test/os/process/exec.wren
+++ b/test/os/process/exec.wren
@@ -32,4 +32,20 @@ if (Platform.isPosix) {
   System.print(Process.exec("ls", ["test"], "./src/")) // expect: 1
 } else if (Platform.name == "Windows") {
   // TODO: can this be done with dir on windows?
+}
+
+// env
+
+if (Platform.isPosix) {
+  System.print(Process.exec("/usr/bin/true",[],null,{})) // expect: 0
+
+  var fiber = Fiber.new {
+    Process.exec("ls",[],null,{"PATH": "/binx/"})
+  }
+  var r = fiber.try()
+  System.print(r) 
+  // expect: Could not launch ls, reason: no such file or directory
+  // expect: Could not spawn process.
+} else if (Platform.name == "Windows") { 
+
 }
\ No newline at end of file

From df6e8baaeef32dab5991b28b3c89a3cd2a58176e Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 20:14:59 -0400
Subject: [PATCH 09/13] questions

---
 test/os/process/exec.wren | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/test/os/process/exec.wren b/test/os/process/exec.wren
index 620e80f8..eaf63a33 100644
--- a/test/os/process/exec.wren
+++ b/test/os/process/exec.wren
@@ -1,5 +1,12 @@
 import "os" for Platform, Process
 
+var TRY = Fn.new { |fn|
+  var fiber = Fiber.new {
+    fn.call()
+  }
+  return fiber.try()
+}
+
 var result
 if(Platform.name == "Windows") {
   result = Process.exec("cmd.exe", [])
@@ -38,13 +45,13 @@ if (Platform.isPosix) {
 
 if (Platform.isPosix) {
   System.print(Process.exec("/usr/bin/true",[],null,{})) // expect: 0
-
-  var fiber = Fiber.new {
-    Process.exec("ls",[],null,{"PATH": "/binx/"})
+  var r = TRY.call { 
+    Process.exec("ls",[],null,{"PATH": "/binx/"}) 
   }
-  var r = fiber.try()
   System.print(r) 
+  // TODO: should be on stderr
   // expect: Could not launch ls, reason: no such file or directory
+  // TODO: should this be a runtime error?????
   // expect: Could not spawn process.
 } else if (Platform.name == "Windows") { 
 

From 4842cd574e32dc6a99e51cff765440820ee79f4e Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 20:21:54 -0400
Subject: [PATCH 10/13] windows is the outlier

---
 src/module/os.c           |  4 +---
 test/os/process/exec.wren | 43 +++++++++++++++++++--------------------
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/src/module/os.c b/src/module/os.c
index 2f45a749..5a3e6020 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -212,10 +212,8 @@ void processExec(WrenVM* vm)
     {
       
       wrenGetListElement(vm, 4, i, 6);
-      //:todo: ensure this is a string, and report an error if not
-
       if (wrenGetSlotType(vm, 6) != WREN_TYPE_STRING) {
-        wrenSetSlotString(vm, 0, "aruments to params are suppose to be string");
+        wrenSetSlotString(vm, 0, "arguments to env are supposed to be string");
         wrenAbortFiber(vm, 0);        
       }
       char* envKeyPlusValue = cli_strdup(wrenGetSlotString(vm, 6));
diff --git a/test/os/process/exec.wren b/test/os/process/exec.wren
index eaf63a33..c2db18da 100644
--- a/test/os/process/exec.wren
+++ b/test/os/process/exec.wren
@@ -9,50 +9,49 @@ var TRY = Fn.new { |fn|
 
 var result
 if(Platform.name == "Windows") {
-  result = Process.exec("cmd.exe", [])
+  result = Process.exec("cmd.exe")
 } else {
-  // works on Mac
-  result = Process.exec("/usr/bin/true", [])
+  result = Process.exec("true")
 }
 System.print(result) // expect: 0
 
 // basics
 
-if (Platform.isPosix) {
+if (Platform.isWindows) {
+  // TODO: more windows argument specific tests
+} else {
   // known output of success/fail based on only command name
-  System.print(Process.exec("/usr/bin/true")) // expect: 0
-  System.print(Process.exec("/usr/bin/false")) // expect: 1
+  System.print(Process.exec("true")) // expect: 0
+  System.print(Process.exec("false")) // expect: 1
   // these test that our arguments are being passed as it proves
   // they effect the result code returned
-  System.print(Process.exec("/bin/test", ["2", "-eq", "2"])) // expect: 0
-  System.print(Process.exec("/bin/test", ["2", "-eq", "3"])) // expect: 1
-} else if (Platform.name == "Windows") {
-  // TODO: more windows argument specific tests
+  System.print(Process.exec("test", ["2", "-eq", "2"])) // expect: 0
+  System.print(Process.exec("test", ["2", "-eq", "3"])) // expect: 1
 }
 
 // cwd
 
-if (Platform.isPosix) {
-  // tests exists in our root
+if (Platform.isWindows) {
+  // TODO: can this be done with dir on windows?
+} else {
+  // tests exists in our project folder
   System.print(Process.exec("ls", ["test"])) // expect: 0
-  // but not in our `src` folder
+  // but does not in our `src` folder
   System.print(Process.exec("ls", ["test"], "./src/")) // expect: 1
-} else if (Platform.name == "Windows") {
-  // TODO: can this be done with dir on windows?
 }
 
 // env
 
-if (Platform.isPosix) {
-  System.print(Process.exec("/usr/bin/true",[],null,{})) // expect: 0
-  var r = TRY.call { 
-    Process.exec("ls",[],null,{"PATH": "/binx/"}) 
+if (Platform.name == "Windows") { 
+  // TODO: how?
+} else {
+  System.print(Process.exec("true",[],null,{})) // expect: 0
+  var result = TRY.call { 
+    Process.exec("ls",[],null,{"PATH": "/whereiscarmen/"}) 
   }
-  System.print(r) 
+  System.print(result) 
   // TODO: should be on stderr
   // expect: Could not launch ls, reason: no such file or directory
   // TODO: should this be a runtime error?????
   // expect: Could not spawn process.
-} else if (Platform.name == "Windows") { 
-
 }
\ No newline at end of file

From 0791b4c09a4adadaeeb8b349bd4869e373ed7e0e Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 20:26:22 -0400
Subject: [PATCH 11/13] clean ups

---
 src/module/os.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/src/module/os.c b/src/module/os.c
index 5a3e6020..3eb483e7 100644
--- a/src/module/os.c
+++ b/src/module/os.c
@@ -164,7 +164,7 @@ static void processOnExit(uv_process_t* req, int64_t exit_status, int term_signa
     {
       free(env);
       index += 1;
-      env = data->options.args[index];
+      env = data->options.env[index];
     }
   }
 
@@ -200,30 +200,20 @@ void processExec(WrenVM* vm)
   if (wrenGetSlotType(vm, 4) == WREN_TYPE_NULL) {
     // no environment specified
   } else if (wrenGetSlotType(vm, 4) == WREN_TYPE_LIST) {
-    // fprintf(stderr,"got list\n");
     int envCount = wrenGetListCount(vm, 4);
     int envSize = sizeof(char*) * (envCount + 1);
 
     data->options.env = (char**)malloc(envSize);
     data->options.env[envCount] = NULL;
 
-    // fprintf(stderr,"envsize %d\n", envCount);
     for (int i = 0; i < envCount ; i++) 
     {
-      
       wrenGetListElement(vm, 4, i, 6);
       if (wrenGetSlotType(vm, 6) != WREN_TYPE_STRING) {
-        wrenSetSlotString(vm, 0, "arguments to env are supposed to be string");
+        wrenSetSlotString(vm, 0, "arguments to env are supposed to be strings");
         wrenAbortFiber(vm, 0);        
       }
       char* envKeyPlusValue = cli_strdup(wrenGetSlotString(vm, 6));
-      // fprintf(stderr,"key: %s\n", envKeyPlusValue);
-      // fprintf(stderr,"setting %s\n", envKeyPlusValue);
-      // char* equalSplit = strchr(envKeyPlusValue, '=');
-      // *equalSplit = '\0';
-      // char* key = envKeyPlusValue;
-      // char* value = equalSplit + 1;
-
       data->options.env[i] = envKeyPlusValue;
     }
   }
@@ -239,7 +229,10 @@ void processExec(WrenVM* vm)
   for (int i = 0; i < argCount; i++) 
   {
     wrenGetListElement(vm, 2, i, 3);
-    //:todo: ensure this is a string, and report an error if not
+    if (wrenGetSlotType(vm, 3) != WREN_TYPE_STRING) {
+      wrenSetSlotString(vm, 0, "arguments to args are supposed to be strings");
+      wrenAbortFiber(vm, 0);        
+    }
     char* arg = cli_strdup(wrenGetSlotString(vm, 3));
     data->options.args[i + 1] = arg;
   }

From 6c3be41e98be6abf7e0fa31328185818239859ac Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 21:11:56 -0400
Subject: [PATCH 12/13] Scheduler.await_

---
 src/module/os.wren     | 3 +--
 src/module/os.wren.inc | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/module/os.wren b/src/module/os.wren
index eec8d92a..b397149e 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -35,8 +35,7 @@ class Process {
     } else {
       Fiber.abort("environment vars must be passed as a Map")
     }
-    exec_(cmd, args, cwd, env, Fiber.current)
-    return Scheduler.runNextScheduled_()
+    return Scheduler.await_ { exec_(cmd, args, cwd, env, Fiber.current) }
   }
 
   foreign static exec_(cmd, args, cwd, env, fiber)
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index 42f2955d..a33ef650 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -39,8 +39,7 @@ static const char* osModuleSource =
 "    } else {\n"
 "      Fiber.abort(\"environment vars must be passed as a Map\")\n"
 "    }\n"
-"    exec_(cmd, args, cwd, env, Fiber.current)\n"
-"    return Scheduler.runNextScheduled_()\n"
+"    return Scheduler.await_ { exec_(cmd, args, cwd, env, Fiber.current) }\n"
 "  }\n"
 "\n"
 "  foreign static exec_(cmd, args, cwd, env, fiber)\n"

From 854a5fcc6df818445c365e3a536a638e2e0073a2 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 2 May 2021 21:13:41 -0400
Subject: [PATCH 13/13] consistency

---
 src/module/os.wren     | 3 ++-
 src/module/os.wren.inc | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/module/os.wren b/src/module/os.wren
index b397149e..80a4c8f6 100644
--- a/src/module/os.wren
+++ b/src/module/os.wren
@@ -13,7 +13,7 @@ class Process {
   static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }
 
   static exec(cmd) {
-    return exec(cmd, [], null, null)
+    return exec(cmd, null, null, null)
   }
 
   static exec(cmd, args) {
@@ -26,6 +26,7 @@ class Process {
   
   static exec(cmd, args, cwd, envMap) { 
     var env = []
+    args = args || []
     if (envMap is Map) {
       for (entry in envMap) {
         env.add([entry.key, entry.value].join("="))
diff --git a/src/module/os.wren.inc b/src/module/os.wren.inc
index a33ef650..8c12009b 100644
--- a/src/module/os.wren.inc
+++ b/src/module/os.wren.inc
@@ -17,7 +17,7 @@ static const char* osModuleSource =
 "  static arguments { allArguments.count >= 2 ? allArguments[2..-1] : [] }\n"
 "\n"
 "  static exec(cmd) {\n"
-"    return exec(cmd, [], null, null)\n"
+"    return exec(cmd, null, null, null)\n"
 "  }\n"
 "\n"
 "  static exec(cmd, args) {\n"
@@ -30,6 +30,7 @@ static const char* osModuleSource =
 "  \n"
 "  static exec(cmd, args, cwd, envMap) { \n"
 "    var env = []\n"
+"    args = args || []\n"
 "    if (envMap is Map) {\n"
 "      for (entry in envMap) {\n"
 "        env.add([entry.key, entry.value].join(\"=\"))\n"