commit f3d451b81c4caa8cce7f55af6463ec685e79e227
Author: Gerd Stolpmann <gerd@gerd-stolpmann.de>
Date:   Sun Feb 26 21:04:49 2017 +0100

    ocaml-4.05: support for O_KEEPEXEC

diff --git a/code/src/netsys/Makefile b/code/src/netsys/Makefile
index cbc1ce2..cb70a09 100644
--- a/code/src/netsys/Makefile
+++ b/code/src/netsys/Makefile
@@ -56,7 +56,7 @@ OCAMLC_OPTIONS_FOR_netsys_c_xdr.c = -ccopt -O
 OCAMLC_OPTIONS += $(STRING_OPTS)
 OCAMLOPT_OPTIONS += $(STRING_OPTS)
 
-PP_OPTIONS = -pp "$(CPPO) $(DEF_O_SHARE_DELETE) $(DEF_O_CLOEXEC) $(PP_BYTES) $(PP_DEPRECATED)"
+PP_OPTIONS = -pp "$(CPPO) $(DEF_O_SHARE_DELETE) $(DEF_O_CLOEXEC) $(DEF_O_KEEPEXEC) $(PP_BYTES) $(PP_DEPRECATED)"
 
 INSTALL_EXTRA += netsys_c_event.h $(OOH_OBJECT)
 
diff --git a/code/src/netsys/configure b/code/src/netsys/configure
index 1325843..f4dbc09 100755
--- a/code/src/netsys/configure
+++ b/code/src/netsys/configure
@@ -437,6 +437,21 @@ else
     echo "no"
 fi
 
+######################################################################
+
+printf "Checking for O_KEEPEXEC... "
+mkdir -p tmp
+cat <<_EOF_ >tmp/t.ml
+let x = Unix.O_KEEPEXEC;;
+_EOF_
+
+def_o_keepexec="-D NO_O_KEEPEXEC"
+if ocaml unix.cma tmp/t.ml >/dev/null 2>/dev/null; then
+    echo "yes"
+    def_o_keepexec="-D HAVE_O_KEEPEXEC"
+else
+    echo "no"
+fi
 
 ######################################################################
 
@@ -445,6 +460,7 @@ cat <<EOF >Makefile.conf
 NETSYS_LINK_OPTIONS = $netsys_link_options
 DEF_O_SHARE_DELETE = $def_o_share_delete
 DEF_O_CLOEXEC = $def_o_cloexec
+DEF_O_KEEPEXEC = $def_o_keepexec
 OOH_OBJECT = $def_ooh_object
 EOF
 
diff --git a/code/src/netsys/netsys_c.c b/code/src/netsys/netsys_c.c
index a8b16be..4c30873 100644
--- a/code/src/netsys/netsys_c.c
+++ b/code/src/netsys/netsys_c.c
@@ -448,32 +448,43 @@ static int at_flags_table[] = {
 #ifndef O_RSYNC
 #define O_RSYNC 0
 #endif
-#ifndef O_CLOEXEC
-#define NEED_CLOEXEC_EMULATION
-#define O_CLOEXEC 0
-#endif
 
 static int open_flag_table[] = {
   O_RDONLY, O_WRONLY, O_RDWR, O_NONBLOCK, O_APPEND, O_CREAT, O_TRUNC, O_EXCL, 
-  O_NOCTTY, O_DSYNC, O_SYNC, O_RSYNC, 0 /* O_SHARE_DELETE */, O_CLOEXEC
+  O_NOCTTY, O_DSYNC, O_SYNC, O_RSYNC,
+  0 /* O_SHARE_DELETE */, 0 /* O_CLOEXEC */, 0 /* O_KEEPEXEC */
 };
 
-#ifdef NEED_CLOEXEC_EMULATION
+enum { CLOEXEC = 1, KEEPEXEC = 2 };
+
 static int open_cloexec_table[] = {
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, CLOEXEC, KEEPEXEC
 };
+#ifndef HAVE_O_KEEPEXEC
+#define unix_cloexec_default 0
 #endif
+
 #endif
 
 CAMLprim value netsys_openat(value dirfd, value path, value flags, value perm)
 {
 #ifdef HAVE_AT
     CAMLparam4(dirfd, path, flags, perm);
-    int ret, cv_flags;
+    int ret, cv_flags, clo_flags, cloexec;
     char * p;
 
     /* shamelessly copied from ocaml distro */
     cv_flags = convert_flag_list(flags, open_flag_table);
+    clo_flags = convert_flag_list(flags, open_cloexec_table);
+    if (clo_flags & CLOEXEC)
+        cloexec = 1;
+    else if (clo_flags & KEEPEXEC)
+        cloexec = 0;
+    else
+        cloexec = unix_cloexec_default;
+#if defined(O_CLOEXEC)
+    if (cloexec) cv_flags |= O_CLOEXEC;
+#endif
     p = stat_alloc(string_length(path) + 1);
     strcpy(p, String_val(path));
     enter_blocking_section();
@@ -481,8 +492,8 @@ CAMLprim value netsys_openat(value dirfd, value path, value flags, value perm)
     leave_blocking_section();
     stat_free(p);
     if (ret == -1) uerror("openat", path);
-#if defined(NEED_CLOEXEC_EMULATION) && defined(FD_CLOEXEC)
-    if (convert_flag_list(flags, open_cloexec_table) != 0) {
+#if !defined(O_CLOEXEC)
+    {
         int flags = fcntl(Int_val(dirfd), F_GETFD, 0);
         if (flags == -1 || fcntl(Int_val(dirfd), F_SETFD, flags | FD_CLOEXEC) == -1)
           uerror("openat", path);
diff --git a/code/src/netsys/netsys_posix.ml b/code/src/netsys/netsys_posix.ml
index 602ceae..3bf3e7c 100644
--- a/code/src/netsys/netsys_posix.ml
+++ b/code/src/netsys/netsys_posix.ml
@@ -715,6 +715,12 @@ type at_flag = AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_SYMLINK_FOLLOW |
                AT_REMOVEDIR
 
 (* The stubs assume these type definitions: *)
+#ifdef HAVE_O_KEEPEXEC
+type open_flag1 = Unix.open_flag =
+    O_RDONLY | O_WRONLY | O_RDWR | O_NONBLOCK | O_APPEND | O_CREAT | O_TRUNC
+  | O_EXCL | O_NOCTTY | O_DSYNC | O_SYNC | O_RSYNC | O_SHARE_DELETE
+  | O_CLOEXEC | O_KEEPEXEC
+#else
 #ifdef HAVE_O_CLOEXEC
 type open_flag1 = Unix.open_flag =
     O_RDONLY | O_WRONLY | O_RDWR | O_NONBLOCK | O_APPEND | O_CREAT | O_TRUNC
@@ -731,6 +737,7 @@ type open_flag1 = Unix.open_flag =
   | O_EXCL | O_NOCTTY | O_DSYNC | O_SYNC | O_RSYNC
 #endif
 #endif
+#endif
 
 type access_permission1 = Unix.access_permission =
     R_OK | W_OK | X_OK | F_OK