Merge branch 'sverker/run_erl-pty-race/OTP-13795' into maint

2 files changed, 39 insertions, 9 deletions

diff --git a/erts/etc/unix/run_erl.c b/erts/etc/unix/run_erl.c
index 30210ac172..6a92e18648 100644
--- a/erts/etc/unix/run_erl.c
+++ b/erts/etc/unix/run_erl.c
@@ -240,6 +240,7 @@ int main(int argc, char **argv)
   int off_argv;
   int calculated_pipename = 0;
   int highest_pipe_num = 0;
+  int sleepy_child = 0;
 
   program_name = argv[0];
 
@@ -250,6 +251,11 @@ int main(int argc, char **argv)
 
   init_outbuf();
 
+  if (!strcmp(argv[1],"-sleepy-child")) {  /* For test purpose only */
+      sleepy_child = 1;
+      ++i;
+  }
+
   if (!strcmp(argv[1],"-daemon")) {
       daemon_init();
       ++i;
@@ -392,6 +398,9 @@ int main(int argc, char **argv)
     exit(1);
   }
   if (childpid == 0) {
+      if (sleepy_child)
+	  sleep(1);
+
     /* Child */
     sf_close(mfd);
     /* disassociate from control terminal */
@@ -904,20 +913,32 @@ static int create_fifo(char *name, int perm)
  * Find a master device, open and return fd and slave device name.
  */
 
+#ifdef HAVE_WORKING_POSIX_OPENPT
+   /*
+    * Use openpty() on OpenBSD even if we have posix_openpt()
+    * as there is a race when read from master pty returns 0
+    * if child has not yet opened slave pty.
+    * (maybe other BSD's have the same problem?)
+    */
+#  if !(defined(__OpenBSD__) && defined(HAVE_OPENPTY))
+#    define TRY_POSIX_OPENPT
+#  endif
+#endif
+
 static int open_pty_master(char **ptyslave, int *sfdp)
 {
   int mfd;
 
 /* Use the posix_openpt if working, as this guarantees creation of the 
    slave device properly. */
-#if defined(HAVE_WORKING_POSIX_OPENPT) || (defined(__sun) && defined(__SVR4))
-#  ifdef HAVE_WORKING_POSIX_OPENPT
-  if ((mfd = posix_openpt(O_RDWR)) >= 0) {
+#if defined(TRY_POSIX_OPENPT) || (defined(__sun) && defined(__SVR4))
+#  ifdef TRY_POSIX_OPENPT
+  mfd = posix_openpt(O_RDWR);
 #  elif defined(__sun) && defined(__SVR4)
   mfd = sf_open("/dev/ptmx", O_RDWR, 0);
+#  endif
 
   if (mfd >= 0) {
-#  endif
       if ((*ptyslave = ptsname(mfd)) != NULL &&
 	  grantpt(mfd) == 0 && 
 	  unlockpt(mfd) == 0) {
diff --git a/erts/test/run_erl_SUITE.erl b/erts/test/run_erl_SUITE.erl
index 47d38bde7c..fe1ccba1e2 100644
--- a/erts/test/run_erl_SUITE.erl
+++ b/erts/test/run_erl_SUITE.erl
@@ -22,6 +22,7 @@
 
 -export([all/0, suite/0]).
 -export([basic/1,heavy/1,heavier/1,defunct/1]).
+-export([sleepy_child/1]).
 -export([ping_me_back/1]).
 
 -include_lib("common_test/include/ct.hrl").
@@ -31,17 +32,17 @@ suite() ->
      {timetrap, {minutes, 2}}].
 
 all() -> 
-    [basic, heavy, heavier, defunct].
+    [basic, sleepy_child, heavy, heavier, defunct].
 
 
 basic(Config) when is_list(Config) ->
     case os:type() of
-	{unix,_} -> basic_1(Config);
+	{unix,_} -> basic_1(Config, "basic", "");
 	_ -> {skip,"Not Unix"}
     end.
 
-basic_1(Config) ->
-    {Node,Pipe} = do_run_erl(Config, "basic"),
+basic_1(Config, Case, Opt) ->
+    {Node,Pipe} = do_run_erl(Config, Case, Opt),
 
     ToErl = open_port({spawn,"to_erl "++Pipe}, []),
     erlang:port_command(ToErl, "halt().\r\n"),
@@ -55,6 +56,12 @@ basic_1(Config) ->
 
     ok.
 
+sleepy_child(Config) when is_list(Config) ->
+    case os:type() of
+	{unix,_} -> basic_1(Config, "sleepy_child", "-sleepy-child ");
+	_ -> {skip,"Not Unix"}
+    end.
+
 heavy(Config) when is_list(Config) ->
     case os:type() of
 	{unix,_} -> heavy_1(Config);
@@ -233,12 +240,14 @@ defunct_2(Config, Perl) ->
 %%% Utilities.
 
 do_run_erl(Config, Case) ->
+    do_run_erl(Config, Case, "").
+do_run_erl(Config, Case, Opt) ->
     Priv = proplists:get_value(priv_dir, Config),
     LogDir = filename:join(Priv, Case),
     ok = file:make_dir(LogDir),
     Pipe = LogDir ++ "/",
     NodeName = "run_erl_node_" ++ Case,
-    Cmd = "run_erl "++Pipe++" "++LogDir++" \"erl -sname " ++ NodeName ++
+    Cmd = "run_erl "++Opt++Pipe++" "++LogDir++" \"erl -sname " ++ NodeName ++
 	" -pa " ++ filename:dirname(code:which(?MODULE)) ++
 	" -s " ++ ?MODULE_STRING ++ " ping_me_back " ++
 	atom_to_list(node()) ++ "\"",