Get tests running on wasm32-wasi

We need to use a fork of splitmix here. We /should/ be able to still
point to the original repo, but Cabal doesn't run a "git fetch" to
download the ref, so you can't point to a commit not on a branch.
This is fixed in latest, but that won't be released for a while.

Author: SquidDev

cabal.project.wasm32-wasi

@@ -0,0 +1,7 @@
+packages: unix-compat.cabal
+
+-- See https://github.com/haskellari/splitmix/pull/73
+source-repository-package
+  type:     git
+  location: https://github.com/amesgen/splitmix.git
+  tag:      cea9e31bdd849eb0c17611bb99e33d590e126164

cbits/mktemp.c

@@ -41,13 +41,21 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+
+#if defined(__wasm__)
+#include <sys/random.h>
+#else
 #include <windows.h>
 #include <wincrypt.h>
 
-static int random(uint32_t *);
+#define open _open
+#define stat _stat
+#endif
+
+static int unixcompat_random(uint32_t *);
 static int _gettemp(char *, int *);
 
-static const unsigned char padchar[] =
+static const char padchar[] =
 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 int unixcompat_mkstemp(char *path)
@@ -64,7 +72,7 @@ static int _gettemp(char *path, int *doopen)
 {
     char *start, *trv, *suffp, *carryp;
     char *pad;
-    struct _stat sbuf;
+    struct stat sbuf;
     int rval;
     uint32_t randidx, randval;
     char carrybuf[MAXPATHLEN];
@@ -84,7 +92,7 @@ static int _gettemp(char *path, int *doopen)
 
     /* Fill space with random characters */
     while (trv >= path && *trv == 'X') {
-        if (!random(&randval)) {
+        if (!unixcompat_random(&randval)) {
             /* this should never happen */
             errno = EIO;
             return 0;
@@ -104,7 +112,7 @@ static int _gettemp(char *path, int *doopen)
         for (; trv > path; --trv) {
             if (*trv == '/') {
                 *trv = '\0';
-                rval = _stat(path, &sbuf);
+                rval = stat(path, &sbuf);
                 *trv = '/';
                 if (rval != 0)
                     return (0);
@@ -120,11 +128,11 @@ static int _gettemp(char *path, int *doopen)
     for (;;) {
         if (doopen) {
             if ((*doopen =
-                _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
+                open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
                 return (1);
             if (errno != EEXIST)
                 return (0);
-        } else if (_stat(path, &sbuf))
+        } else if (stat(path, &sbuf))
             return (errno == ENOENT);
 
         /* If we have a collision, cycle through the space of filenames */
@@ -154,7 +162,14 @@ static int _gettemp(char *path, int *doopen)
     /*NOTREACHED*/
 }
 
-static int random(uint32_t *value)
+#if defined(__wasm__)
+static int unixcompat_random(uint32_t *value)
+{
+    int r = getentropy(value, sizeof(uint32_t));
+    return r == 0 ? 1 : 0;
+}
+#else
+static int unixcompat_random(uint32_t *value)
 {
     /* This handle is never released. Windows will clean up when the process
      * exits. Python takes this approach when emulating /dev/urandom, and if
@@ -171,3 +186,4 @@ static int random(uint32_t *value)
 
     return 1;
 }
+#endif

src/System/PosixCompat/Process.hs

@@ -8,14 +8,21 @@ module System.PosixCompat.Process (
       getProcessID
     ) where
 
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS)
 
 import System.Posix.Types (ProcessID)
 import System.Win32.Process (getCurrentProcessId)
 
 getProcessID :: IO ProcessID
 getProcessID = fromIntegral <$> getCurrentProcessId
 
+#elif defined(wasm32_HOST_ARCH)
+
+import System.Posix.Types (ProcessID)
+
+getProcessID :: IO ProcessID
+getProcessID = pure 1
+
 #else
 
 import System.Posix.Process

src/System/PosixCompat/Temp.hs

@@ -11,13 +11,13 @@ module System.PosixCompat.Temp (
       mkstemp
     ) where
 
-#ifndef mingw32_HOST_OS
+#if !(defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH))
 -- Re-export unix package
 
 import System.Posix.Temp
 
 #elif defined(__GLASGOW_HASKELL__)
--- Windows w/ GHC, we have fdToHandle so we
+-- Window/WASM w/ GHC, we have fdToHandle so we
 -- can use our own implementation of mkstemp.
 
 import System.IO (Handle)

tests/run-wasmtime.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env sh
+
+TMP="$(mktemp -d --suffix=-unix-compat)"
+trap 'rm -rf -- "$TMP"' EXIT
+wasmtime --dir "$TMP::/" "$@"
+exit "$?"

unix-compat.cabal

@@ -69,7 +69,9 @@ Library
 
   else
     build-depends: unix      >= 2.7.2.0  && < 2.9
-    if !arch(wasm32)
+    if arch(wasm32)
+      c-sources: cbits/mktemp.c
+    else
       include-dirs: include
       includes: HsUnixCompat.h
       install-includes: HsUnixCompat.h