[WIP] Libnethack shared

CMakeLists.txt

@@ -27,6 +27,7 @@ endif()
 
 message(STATUS "Building nle backend version: ${NLE_VERSION}")
 
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 # We use this to decide where the root of the nle/ package is. Normally it
@@ -99,7 +100,7 @@ target_link_directories(nethack PUBLIC /usr/local/lib)
 target_link_libraries(nethack PUBLIC m fcontext bz2)
 
 # dlopen wrapper library
-add_library(nethackdl STATIC "sys/unix/nledl.c")
+add_library(nethackdl STATIC "sys/unix/nledl.c" "sys/unix/nleshared.cc")
 target_include_directories(nethackdl PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 target_link_libraries(nethackdl PUBLIC dl)
 

include/nledl.h

@@ -10,15 +10,9 @@
 #include "nleobs.h"
 
 /* TODO: Don't call this nle_ctx_t as well. */
-typedef struct nledl_ctx {
-    char dlpath[1024];
-    void *dlhandle;
-    void *nle_ctx;
-    void *(*step)(void *, nle_obs *);
-    FILE *ttyrec;
-} nle_ctx_t;
-
-nle_ctx_t *nle_start(const char *, nle_obs *, FILE *, nle_seeds_init_t *);
+typedef struct nledl_ctx nle_ctx_t;
+
+nle_ctx_t *nle_start(const char *, nle_obs *, FILE *, nle_seeds_init_t *, int shared);
 nle_ctx_t *nle_step(nle_ctx_t *, nle_obs *);
 
 void nle_reset(nle_ctx_t *, nle_obs *, FILE *, nle_seeds_init_t *);
@@ -27,4 +21,6 @@ void nle_end(nle_ctx_t *);
 void nle_set_seed(nle_ctx_t *, unsigned long, unsigned long, char);
 void nle_get_seed(nle_ctx_t *, unsigned long *, unsigned long *, char *);
 
+int nle_supports_shared(void);
+
 #endif /* NLEDL_H */

nle/nethack/nethack.py

@@ -75,13 +75,13 @@ def _set_env_vars(options, hackdir, wizkit=None):
     if wizkit is not None:
         os.environ["WIZKIT"] = wizkit
 
+_nhinstances = 0
 
 # TODO: Not thread-safe for many reasons.
 # TODO: On Linux, we could use dlmopen to use different linker namespaces,
 # which should allow several instances of this. On MacOS, that seems
 # a tough call.
 class Nethack:
-    _instances = 0
 
     def __init__(
         self,
@@ -93,34 +93,56 @@ def __init__(
         wizard=False,
         hackdir=HACKDIR,
     ):
+        global _nhinstances
         self._copy = copy
 
+        _nhinstances = _nhinstances + 1
+
         if not os.path.exists(hackdir) or not os.path.exists(
             os.path.join(hackdir, "sysconf")
         ):
             raise FileNotFoundError(
                 "Couldn't find NetHack installation at '%s'." % hackdir
             )
 
-        # Create a HACKDIR for us.
-        self._tempdir = tempfile.TemporaryDirectory(prefix="nle")
-        self._vardir = self._tempdir.name
-
-        # Save cwd and restore later. Currently libnethack changes
-        # directory on loading.
-        self._oldcwd = os.getcwd()
+        self.shared = False;
 
-        # Symlink a few files.
-        for fn in ["nhdat", "sysconf"]:
-            os.symlink(os.path.join(hackdir, fn), os.path.join(self._vardir, fn))
-        # Touch a few files.
-        for fn in ["perm", "logfile", "xlogfile"]:
-            os.close(os.open(os.path.join(self._vardir, fn), os.O_CREAT))
-        os.mkdir(os.path.join(self._vardir, "save"))
+        if _pynethack.supports_shared():
+          # "shared" mode does some hacky things to enable using a
+          # shared libnethack.so, prevents writing to any files, and does
+          # not chdir.
+          self.shared = True
+          dlpath = DLPATH
+          self._hackdir = hackdir
+        else:
 
-        # Hacky AF: Copy our so into this directory to load several copies ...
-        dlpath = os.path.join(self._vardir, "libnethack.so")
-        shutil.copyfile(DLPATH, dlpath)
+          # Create a HACKDIR for us.
+          if os.getenv("SLURM_JOBID"):
+            self._tempdir = None
+            self._vardir = "/scratch/slurm_tmpdir/%s/nle-%d-%d" % (os.getenv("SLURM_JOBID"), os.getpid(), _nhinstances)
+            os.mkdir(self._vardir)
+          else:
+            self._tempdir = tempfile.TemporaryDirectory(prefix="nle")
+            self._vardir = self._tempdir.name
+          print("_vardir is ", self._vardir)
+
+          self._hackdir = self._vardir
+
+          # Save cwd and restore later. Currently libnethack changes
+          # directory on loading.
+          self._oldcwd = os.getcwd()
+
+          # Symlink a few files.
+          for fn in ["nhdat", "sysconf"]:
+              os.symlink(os.path.join(hackdir, fn), os.path.join(self._vardir, fn))
+          # Touch a few files.
+          for fn in ["perm", "logfile", "xlogfile"]:
+              os.close(os.open(os.path.join(self._vardir, fn), os.O_CREAT))
+          os.mkdir(os.path.join(self._vardir, "save"))
+
+          # Hacky AF: Copy our so into this directory to load several copies ...
+          dlpath = os.path.join(self._vardir, "libnethack.so")
+          shutil.copyfile(DLPATH, dlpath)
 
         if options is None:
             options = NETHACKOPTIONS
@@ -129,10 +151,10 @@ def __init__(
             self._options.append("playmode:debug")
         self._wizard = wizard
 
-        _set_env_vars(self._options, self._vardir)
+        _set_env_vars(self._options, self._hackdir)
         self._ttyrec = ttyrec
 
-        self._pynethack = _pynethack.Nethack(dlpath, ttyrec)
+        self._pynethack = _pynethack.Nethack(dlpath, ttyrec, self.shared)
 
         self._obs_buffers = {}
 
@@ -154,6 +176,8 @@ def step(self, action):
         return self._step_return(), self._pynethack.done()
 
     def _write_wizkit_file(self, wizkit_items):
+        if self._vardir is None:
+            raise RuntimeError("FIXME: shared wizkit: can't write to HACKDIR as it is a shared directory")
         # TODO ideally we need to check the validity of the requested items
         with open(os.path.join(self._vardir, WIZKIT_FNAME), "w") as f:
             for item in wizkit_items:
@@ -164,9 +188,9 @@ def reset(self, new_ttyrec=None, wizkit_items=None):
             if not self._wizard:
                 raise ValueError("Set wizard=True to use the wizkit option.")
             self._write_wizkit_file(wizkit_items)
-            _set_env_vars(self._options, self._vardir, wizkit=WIZKIT_FNAME)
+            _set_env_vars(self._options, self._hackdir, wizkit=WIZKIT_FNAME)
         else:
-            _set_env_vars(self._options, self._vardir)
+            _set_env_vars(self._options, self._hackdir)
         if new_ttyrec is None:
             self._pynethack.reset()
         else:
@@ -178,11 +202,13 @@ def reset(self, new_ttyrec=None, wizkit_items=None):
 
     def close(self):
         self._pynethack.close()
-        try:
-            os.chdir(self._oldcwd)
-        except IOError:
-            os.chdir(os.path.dirname(os.path.realpath(__file__)))
-        self._tempdir.cleanup()
+        if not self.shared:
+          try:
+              os.chdir(self._oldcwd)
+          except IOError:
+              os.chdir(os.path.dirname(os.path.realpath(__file__)))
+          if self._tempdir is not None:
+              self._tempdir.cleanup()
 
     def set_initial_seeds(self, core, disp, reseed=False):
         self._pynethack.set_initial_seeds(core, disp, reseed)

sys/unix/nledl.c

@@ -6,74 +6,110 @@
 
 #include "nledl.h"
 
-void
-nledl_init(nle_ctx_t *nledl, nle_obs *obs, nle_seeds_init_t *seed_init)
-{
-    nledl->dlhandle = dlopen(nledl->dlpath, RTLD_LAZY);
-
-    if (!nledl->dlhandle) {
-        fprintf(stderr, "%s\n", dlerror());
-        exit(EXIT_FAILURE);
-    }
-
-    dlerror(); /* Clear any existing error */
-
+void* nleshared_open(const char *dlpath);
+void nleshared_close(void* handle);
+void nleshared_reset(void* handle);
+void* nleshared_sym(void* handle, const char* symname);
+void nleshared_set_current(void* handle);
+int nleshared_supported(void);
+
+typedef struct nledl_ctx {
+    void* shared;
+    char dlpath[1024];
+    void *dlhandle;
+    void *nle_ctx;
     void *(*start)(nle_obs *, FILE *, nle_seeds_init_t *);
-    start = dlsym(nledl->dlhandle, "nle_start");
-    nledl->nle_ctx = start(obs, nledl->ttyrec, seed_init);
+    void *(*step)(void *, nle_obs *);
+    void (*end)(void *);
+    FILE *ttyrec;
+} nle_ctx_t;
 
+static void* sym(nle_ctx_t *nledl, const char* name) {
+  if (nledl->shared) {
+    return nleshared_sym(nledl->shared, name);
+  } else {
+    dlerror(); /* Clear any existing error */
+    void* r = dlsym(nledl->dlhandle, name);
     char *error = dlerror();
     if (error != NULL) {
         fprintf(stderr, "%s\n", error);
         exit(EXIT_FAILURE);
     }
+    return r;
+  }
+}
 
-    nledl->step = dlsym(nledl->dlhandle, "nle_step");
-
-    error = dlerror();
-    if (error != NULL) {
-        fprintf(stderr, "%s\n", error);
+void
+nledl_init(nle_ctx_t *nledl, nle_obs *obs, nle_seeds_init_t *seed_init, int shared)
+{ 
+  nledl->shared = NULL;
+  if (shared) {
+    if (nleshared_supported()) {
+      nledl->shared = nleshared_open(nledl->dlpath);
+      nleshared_set_current(nledl->shared);
+    } else {
+      fprintf(stderr, "Shared mode not supported on this system!\n");
+      exit(EXIT_FAILURE);
+    }
+  } else {
+    nledl->dlhandle = dlopen(nledl->dlpath, RTLD_LAZY);
+    if (!nledl->dlhandle) {
+        fprintf(stderr, "%s\n", dlerror());
         exit(EXIT_FAILURE);
     }
+  }
+
+  nledl->start = sym(nledl, "nle_start");
+  nledl->step = sym(nledl, "nle_step");
+  nledl->end = sym(nledl, "nle_end");
+
+  nledl->nle_ctx = nledl->start(obs, nledl->ttyrec, seed_init);
 }
 
 void
 nledl_close(nle_ctx_t *nledl)
 {
-    void (*end)(void *);
+    if (nledl->shared) {
+      nleshared_set_current(nledl->shared);
+    }
+    nledl->end(nledl->nle_ctx);
 
-    end = dlsym(nledl->dlhandle, "nle_end");
-    end(nledl->nle_ctx);
+    if (nledl->shared) {
+      nleshared_close(nledl->shared);
+    } else {
+      if (dlclose(nledl->dlhandle)) {
+          fprintf(stderr, "Error in dlclose: %s\n", dlerror());
+          exit(EXIT_FAILURE);
+      }
 
-    if (dlclose(nledl->dlhandle)) {
-        fprintf(stderr, "Error in dlclose: %s\n", dlerror());
-        exit(EXIT_FAILURE);
+      dlerror();
     }
-
-    dlerror();
 }
 
 nle_ctx_t *
 nle_start(const char *dlpath, nle_obs *obs, FILE *ttyrec,
-          nle_seeds_init_t *seed_init)
+          nle_seeds_init_t *seed_init, int shared)
 {
     /* TODO: Consider getting ttyrec path from caller? */
     struct nledl_ctx *nledl = malloc(sizeof(struct nledl_ctx));
     nledl->ttyrec = ttyrec;
     strncpy(nledl->dlpath, dlpath, sizeof(nledl->dlpath));
 
-    nledl_init(nledl, obs, seed_init);
+    nledl_init(nledl, obs, seed_init, shared);
     return nledl;
 };
 
 nle_ctx_t *
 nle_step(nle_ctx_t *nledl, nle_obs *obs)
 {
-    if (!nledl || !nledl->dlhandle || !nledl->nle_ctx) {
+    if (!nledl || (!nledl->dlhandle && !nledl->shared) || !nledl->nle_ctx) {
         fprintf(stderr, "Illegal nledl_ctx\n");
         exit(EXIT_FAILURE);
     }
 
+    if (nledl->shared) {
+      nleshared_set_current(nledl->shared);
+    }
     nledl->step(nledl->nle_ctx, obs);
 
     return nledl;
@@ -85,14 +121,25 @@ void
 nle_reset(nle_ctx_t *nledl, nle_obs *obs, FILE *ttyrec,
           nle_seeds_init_t *seed_init)
 {
-    nledl_close(nledl);
-    /* Reset file only if not-NULL. */
-    if (ttyrec)
-        nledl->ttyrec = ttyrec;
-
-    // TODO: Consider refactoring nledl.h such that we expose this init
-    // function but drop reset.
-    nledl_init(nledl, obs, seed_init);
+    if (nledl->shared) {
+      if (nledl->shared) {
+        nleshared_set_current(nledl->shared);
+      }
+      nledl->end(nledl->nle_ctx);
+      nleshared_reset(nledl->shared);
+      if (ttyrec)
+          nledl->ttyrec = ttyrec;
+      nledl->nle_ctx = nledl->start(obs, ttyrec, seed_init);
+    } else {
+      nledl_close(nledl);
+      /* Reset file only if not-NULL. */
+      if (ttyrec)
+          nledl->ttyrec = ttyrec;
+
+      // TODO: Consider refactoring nledl.h such that we expose this init
+      // function but drop reset.
+      nledl_init(nledl, obs, seed_init, 0);
+    }
 }
 
 void
@@ -108,13 +155,7 @@ nle_set_seed(nle_ctx_t *nledl, unsigned long core, unsigned long disp,
 {
     void (*set_seed)(void *, unsigned long, unsigned long, char);
 
-    set_seed = dlsym(nledl->dlhandle, "nle_set_seed");
-
-    char *error = dlerror();
-    if (error != NULL) {
-        fprintf(stderr, "%s\n", error);
-        exit(EXIT_FAILURE);
-    }
+    set_seed = sym(nledl, "nle_set_seed");
 
     set_seed(nledl->nle_ctx, core, disp, reseed);
 }
@@ -125,16 +166,15 @@ nle_get_seed(nle_ctx_t *nledl, unsigned long *core, unsigned long *disp,
 {
     void (*get_seed)(void *, unsigned long *, unsigned long *, char *);
 
-    get_seed = dlsym(nledl->dlhandle, "nle_get_seed");
-
-    char *error = dlerror();
-    if (error != NULL) {
-        fprintf(stderr, "%s\n", error);
-        exit(EXIT_FAILURE);
-    }
+    get_seed = sym(nledl, "nle_get_seed");
 
     /* Careful here. NetHack has different ideas of what a boolean is
      * than C++ (see global.h and SKIP_BOOLEAN). But one byte should be fine.
      */
     get_seed(nledl->nle_ctx, core, disp, reseed);
 }
+
+int
+nle_supports_shared(void) {
+  return nleshared_supported();
+}