diff --git a/libc/stdio/tmpfile.c b/libc/stdio/tmpfile.c
index 66d4be90..b2197e46 100644
--- a/libc/stdio/tmpfile.c
+++ b/libc/stdio/tmpfile.c
@@ -16,10 +16,14 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/safemacros.internal.h"
 #include "libc/calls/calls.h"
 #include "libc/fmt/fmt.h"
+#include "libc/macros.internal.h"
+#include "libc/runtime/runtime.h"
 #include "libc/stdio/stdio.h"
 #include "libc/stdio/temp.h"
+#include "libc/str/str.h"
 
 /**
  * Creates a temporary file.
@@ -28,7 +32,13 @@
  */
 FILE *tmpfile(void) {
   int fd;
-  char template[] = "/tmp/tmp.XXXXXX";
-  if ((fd = mkostemps(template, 0, 0)) == -1) return NULL;
-  return fdopen(fd, "w+");
+  char *tmp, *sep, tpl[PATH_MAX];
+  tmp = firstnonnull(getenv("TMPDIR"), kTmpPath);
+  sep = !isempty(tmp) && !endswith(tmp, "/") ? "/" : "";
+  if (snprintf(tpl, PATH_MAX, "%s%stmp.XXXXXX", tmp, sep) < PATH_MAX) {
+    if ((fd = mkostemps(tpl, 0, 0)) != -1) {
+      return fdopen(fd, "w+");
+    }
+  }
+  return NULL;
 }
diff --git a/test/libc/stdio/tmpfile_test.c b/test/libc/stdio/tmpfile_test.c
new file mode 100644
index 00000000..0a373b83
--- /dev/null
+++ b/test/libc/stdio/tmpfile_test.c
@@ -0,0 +1,40 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/errno.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/stdio.h"
+#include "libc/stdio/temp.h"
+#include "libc/testlib/testlib.h"
+
+char testlib_enable_tmp_setup_teardown;
+
+TEST(tmpfile, test) {
+  FILE *f;
+  mkdir("doge", 0755);
+  setenv("TMPDIR", "doge", true);
+  f = tmpfile();
+  EXPECT_NE(-1, fputc('t', f));
+  EXPECT_NE(-1, fflush(f));
+  rewind(f);
+  EXPECT_EQ('t', fgetc(f));
+  EXPECT_NE(-1, fclose(f));
+  /* EXPECT_EQ(-1, rmdir("doge")); */
+  /* EXPECT_EQ(ENOTEMPTY, errno); */
+}
diff --git a/third_party/lua/loslib.c b/third_party/lua/loslib.c
index 10bd451f..92f60255 100644
--- a/third_party/lua/loslib.c
+++ b/third_party/lua/loslib.c
@@ -10,6 +10,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/weirdtypes.h"
 #include "libc/errno.h"
+#include "libc/runtime/runtime.h"
 #include "libc/stdio/temp.h"
 #include "libc/sysv/consts/exit.h"
 #include "libc/time/struct/tm.h"
@@ -114,12 +115,9 @@
 
 #define LUA_TMPNAMBUFSIZE	32
 
-#if !defined(LUA_TMPNAMTEMPLATE)
-#define LUA_TMPNAMTEMPLATE	"/tmp/lua_XXXXXX"
-#endif
-
 #define lua_tmpnam(b,e) { \
-        strcpy(b, LUA_TMPNAMTEMPLATE); \
+        strcpy(b, kTmpPath); \
+        strcat(b, "lua_XXXXXX"); \
         e = mkstemp(b); \
         if (e != -1) close(e); \
         e = (e == -1); }