win, process: uv_kill improvements

Maps pid 0 to the current process, simulating Linux kill sending signal
to the process group.

Adds detection of invalid signals. If the signum is invalid - below 0
or NSIG or above – UV_EINVAL will be returned instead of UV_ENOSYS.

PR-URL: https://github.com/libuv/libuv/pull/1642
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

src/win/process.c

@@ -1173,6 +1173,10 @@ int uv_spawn(uv_loop_t* loop,
 
 
 static int uv__kill(HANDLE process_handle, int signum) {
+  if (signum < 0 || signum >= NSIG) {
+    return UV_EINVAL;
+  }
+
   switch (signum) {
     case SIGTERM:
     case SIGKILL:
@@ -1237,8 +1241,15 @@ int uv_process_kill(uv_process_t* process, int signum) {
 
 int uv_kill(int pid, int signum) {
   int err;
-  HANDLE process_handle = OpenProcess(PROCESS_TERMINATE |
+  HANDLE process_handle;
-    PROCESS_QUERY_INFORMATION, FALSE, pid);
+
+  if (pid == 0) {
+    process_handle = GetCurrentProcess();
+  } else {
+    process_handle = OpenProcess(PROCESS_TERMINATE | PROCESS_QUERY_INFORMATION,
+                                 FALSE,
+                                 pid);
+  }
 
   if (process_handle == NULL) {
     err = GetLastError();

test/test-list.h

@@ -266,6 +266,7 @@ TEST_DECLARE   (spawn_tcp_server)
 TEST_DECLARE   (fs_poll)
 TEST_DECLARE   (fs_poll_getpath)
 TEST_DECLARE   (kill)
+TEST_DECLARE   (kill_invalid_signum)
 TEST_DECLARE   (fs_file_noent)
 TEST_DECLARE   (fs_file_nametoolong)
 TEST_DECLARE   (fs_file_loop)
@@ -756,6 +757,7 @@ TASK_LIST_START
   TEST_ENTRY  (fs_poll)
   TEST_ENTRY  (fs_poll_getpath)
   TEST_ENTRY  (kill)
+  TEST_ENTRY  (kill_invalid_signum)
 
   TEST_ENTRY  (poll_close_doesnt_corrupt_stack)
   TEST_ENTRY  (poll_closesocket)

test/test-signal.c

@@ -22,6 +22,26 @@
 #include "uv.h"
 #include "task.h"
 
+#ifndef _WIN32
+#include <unistd.h>
+#endif
+
+TEST_IMPL(kill_invalid_signum) {
+  uv_pid_t pid;
+
+  pid = uv_os_getpid();
+
+  ASSERT(uv_kill(pid, -1) == UV_EINVAL);
+#ifdef _WIN32
+  /* NSIG is not available on all platforms. */
+  ASSERT(uv_kill(pid, NSIG) == UV_EINVAL);
+#endif
+  ASSERT(uv_kill(pid, 4096) == UV_EINVAL);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}
+
 /* For Windows we test only signum handling */
 #ifdef _WIN32
 static void signum_test_cb(uv_signal_t* handle, int signum) {