From 1fc72276f91c7d378f14dfd0bb6b0ca8667e4bc5 Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Fri, 9 Aug 2019 13:34:20 +0200
Subject: [PATCH] win: fix uv_spawn() ENOMEM on empty env

Commit ba780231 ("unix,win: handle zero-sized allocations uniformly")
makes `uv__malloc()` return NULL when `size == 0`.

That's exactly the size that is passed to it when uv_spawn() tries to
spawn a process with an empty environment so handle that edge case.

Fixes: https://github.com/nodejs/node/issues/29008
PR-URL: https://github.com/libuv/libuv/pull/2408
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jameson Nash <vtjnash+github@gmail.com>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
---
 src/win/process.c |  4 ++--
 test/test-list.h  |  2 ++
 test/test-spawn.c | 28 ++++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/win/process.c b/src/win/process.c
index f9c53de0..9b7fdc1d 100644
--- a/src/win/process.c
+++ b/src/win/process.c
@@ -714,7 +714,7 @@ int make_program_env(char* env_block[], WCHAR** dst_ptr) {
 
   /* second pass: copy to UTF-16 environment block */
   dst_copy = (WCHAR*)uv__malloc(env_len * sizeof(WCHAR));
-  if (!dst_copy) {
+  if (dst_copy == NULL && env_len > 0) {
     return ERROR_OUTOFMEMORY;
   }
   env_copy = alloca(env_block_count * sizeof(WCHAR*));
@@ -739,7 +739,7 @@ int make_program_env(char* env_block[], WCHAR** dst_ptr) {
     }
   }
   *ptr_copy = NULL;
-  assert(env_len == (size_t) (ptr - dst_copy));
+  assert(env_len == 0 || env_len == (size_t) (ptr - dst_copy));
 
   /* sort our (UTF-16) copy */
   qsort(env_copy, env_block_count-1, sizeof(wchar_t*), qsort_wcscmp);
diff --git a/test/test-list.h b/test/test-list.h
index 3f94360f..6eb8ecad 100644
--- a/test/test-list.h
+++ b/test/test-list.h
@@ -264,6 +264,7 @@ TEST_DECLARE   (spawn_fails)
 #ifndef _WIN32
 TEST_DECLARE   (spawn_fails_check_for_waitpid_cleanup)
 #endif
+TEST_DECLARE   (spawn_empty_env)
 TEST_DECLARE   (spawn_exit_code)
 TEST_DECLARE   (spawn_stdout)
 TEST_DECLARE   (spawn_stdin)
@@ -829,6 +830,7 @@ TASK_LIST_START
 #ifndef _WIN32
   TEST_ENTRY  (spawn_fails_check_for_waitpid_cleanup)
 #endif
+  TEST_ENTRY  (spawn_empty_env)
   TEST_ENTRY  (spawn_exit_code)
   TEST_ENTRY  (spawn_stdout)
   TEST_ENTRY  (spawn_stdin)
diff --git a/test/test-spawn.c b/test/test-spawn.c
index fea1165d..fec610bf 100644
--- a/test/test-spawn.c
+++ b/test/test-spawn.c
@@ -232,6 +232,34 @@ TEST_IMPL(spawn_fails_check_for_waitpid_cleanup) {
 #endif
 
 
+TEST_IMPL(spawn_empty_env) {
+  char* env[1];
+
+  /* The autotools dynamic library build requires the presence of
+   * DYLD_LIBARY_PATH (macOS) or LD_LIBRARY_PATH (other Unices)
+   * in the environment, but of course that doesn't work with
+   * the empty environment that we're testing here.
+   */
+  if (NULL != getenv("DYLD_LIBARY_PATH") ||
+      NULL != getenv("LD_LIBRARY_PATH")) {
+    RETURN_SKIP("doesn't work with DYLD_LIBRARY_PATH/LD_LIBRARY_PATH");
+  }
+
+  init_process_options("spawn_helper1", exit_cb);
+  options.env = env;
+  env[0] = NULL;
+
+  ASSERT(0 == uv_spawn(uv_default_loop(), &process, &options));
+  ASSERT(0 == uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  ASSERT(exit_cb_called == 1);
+  ASSERT(close_cb_called == 1);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}
+
+
 TEST_IMPL(spawn_exit_code) {
   int r;