Write a test for child process cleanup on VM crash

TODO: Needs to be tested on win32

erts/emulator/test/port_SUITE.erl

@@ -130,6 +130,7 @@
     stream_small/1,
     t_binary/1,
     t_exit/1,
+    terminate_children/1,
     tps_16_bytes/1,
     tps_1K/1,
     unregister_name/1,
@@ -178,6 +179,7 @@ all() ->
      mix_up_ports, otp_5112, otp_5119,
      exit_status_multi_scheduling_block, ports, spawn_driver,
      spawn_executable, close_deaf_port, unregister_name,
+     terminate_children,
      port_setget_data,
      parallelism_option,
      mon_port_invalid_type,
@@ -1699,6 +1701,37 @@ spawn_executable(Config) when is_list(Config) ->
     end,
     ok.
 
+
+terminate_children(Config) when is_list(Config) ->
+    DataDir = proplists:get_value(data_dir, Config),
+    PrivDir = proplists:get_value(priv_dir, Config),
+    FileWhileAlive = os:find_executable("file_while_alive", DataDir),
+    TmpFile = filename:join(PrivDir, "file_while_alive_file"),
+    % TODO: Is this guaranteed to find the erl under test?
+    Port = open_port({spawn_executable, os:find_executable("erl")}, [
+        {args, [
+            "-noshell",
+            "-eval",
+            "Port_1 = open_port(" ++
+                "{spawn_executable, \"" ++ FileWhileAlive ++ "\"}," ++
+                "[{args, [\"" ++ TmpFile ++ "\"]}, use_stdio, in])," ++
+            "receive {Port_1, {data, \"waiting.\"}} -> ok " ++
+            "after 10000 -> error(no_child) end," ++
+            "halt()."
+        ]},
+        exit_status, in
+    ]),
+    true = is_port(Port),
+    receive
+        {Port, {exit_status, 0}} -> ok;
+        {Port, {exit_status, 1}} -> ?assert(false)
+    after 10000 -> ?assert(false) end,
+    % TODO: receive "removed." message rather than sleep.
+    receive after 1000 -> ok end,
+    {error, enoent} = file:read_file(TmpFile),
+    ok.
+
+
 unregister_name(Config) when is_list(Config) ->
     Cmd = case os:getenv("WSLENV") of
               false -> "sleep 5";

erts/emulator/test/port_SUITE_data/Makefile.src

@@ -3,7 +3,7 @@ LD = @LD@
 CFLAGS = @CFLAGS@ -I@erl_include@ @DEFS@
 CROSSLDFLAGS = @CROSSLDFLAGS@
 
-PROGS = port_test@exe@ echo_args@exe@ dead_port@exe@
+PROGS = port_test@exe@ echo_args@exe@ dead_port@exe@ file_while_alive@exe@
 DRIVERS = echo_drv@dll@ exit_drv@dll@ failure_drv@dll@ sleep_failure_drv@dll@
 
 all: $(PROGS) $(DRIVERS) port_test.@EMULATOR@
@@ -26,6 +26,12 @@ dead_port@exe@: dead_port@obj@
 dead_port@obj@: dead_port.c
 	$(CC) -c -o dead_port@obj@ $(CFLAGS) dead_port.c
 
+file_while_alive@exe@: file_while_alive@obj@
+	$(LD) $(CROSSLDFLAGS) -o file_while_alive file_while_alive@obj@ @LIBS@
+
+file_while_alive@obj@: file_while_alive.c
+	$(CC) -c -o file_while_alive@obj@ $(CFLAGS) file_while_alive.c
+
 port_test.@EMULATOR@:		port_test.erl
 	@erl_name@ -compile port_test
 

erts/emulator/test/port_SUITE_data/file_while_alive.c

@@ -0,0 +1,86 @@
+/*
+ * Test utility which waits for SIGTERM and responds by deleting a temp file
+ * path.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#ifndef __WIN32__
+#include <unistd.h>
+
+#define O_BINARY 0
+#define _setmode(fd, mode)
+#endif
+
+#ifdef __WIN32__
+#include "windows.h"
+#include "winbase.h"
+#endif
+
+extern int errno;
+
+const char* MSG_WAITING = "waiting.";
+int ERL_FD = 1;
+
+char* tmp_file;
+
+static void handle_sigterm(int sig);
+static void delay(unsigned ms);
+static void write_erl(const char* buf, unsigned size);
+
+int main(int argc, char *argv[]) {
+    if (argc != 2)
+        exit(1);
+
+    tmp_file = argv[1];
+
+    struct sigaction sa;
+    sa.sa_handler = &handle_sigterm;
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+    if (sigaction(SIGTERM, &sa, 0) == -1) {
+        fprintf(stderr, "Failed to set signal handler: %d\n", errno);
+        exit(1);
+    }
+
+    _setmode(ERL_FD, O_BINARY);
+
+    write_erl(MSG_WAITING, sizeof(MSG_WAITING));
+    /* Wait 60s for SIGTERM. */
+    delay(60000);
+
+    fprintf(stderr, "Failure to stop child process.\n");
+
+    return 1;
+}
+
+static void
+write_erl(const char* buf, unsigned size) {
+    if (size != write(ERL_FD, buf, size)) {
+        fprintf(stderr, "Failed to write message to erlang (%d): %s\n", errno, buf);
+        exit(1);
+    }
+}
+
+static void
+handle_sigterm(int sig) {
+    unlink(tmp_file);
+    /* TODO: Ideally we send a message to the grandparent process here. */
+}
+
+static void
+delay(unsigned ms)
+{
+#ifdef __WIN32__
+    Sleep(ms);
+#else
+    struct timeval t;
+    t.tv_sec = ms/1000;
+    t.tv_usec = (ms % 1000) * 1000;
+
+    select(0, NULL, NULL, NULL, &t);
+#endif
+}