From 74b421cc877e412c4eda06757396a1e19fc756ba Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Mon, 15 Jul 2019 11:53:23 +1000
Subject: [PATCH 3/3] (perl #134221) support O_APPEND for open ..., undef on
 VMS
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VMS doesn't allow you to delete an open file like POSIXish systems
do, but you can mark a file to be deleted once it's closed, but
only when you open it.

Since VMS doesn't (yet) have mkostemp() we can add our own flag to
our mkostemp() emulation to pass the necessary magic to open() call
to delete the file on close.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 perlio.c | 10 ++++++----
 util.c   | 15 ++++++++++++++-
 util.h   | 11 +++++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/perlio.c b/perlio.c
index 81ebc156ad..805959f840 100644
--- a/perlio.c
+++ b/perlio.c
@@ -5062,7 +5062,7 @@ PerlIO_tmpfile_flags(int imode)
      const int fd = win32_tmpfd_mode(imode);
      if (fd >= 0)
 	  f = PerlIO_fdopen(fd, "w+b");
-#elif ! defined(VMS) && ! defined(OS2)
+#elif ! defined(OS2)
      int fd = -1;
      char tempname[] = "/tmp/PerlIO_XXXXXX";
      const char * const tmpdir = TAINTING_get ? NULL : PerlEnv_getenv("TMPDIR");
@@ -5073,19 +5073,19 @@ PerlIO_tmpfile_flags(int imode)
 	 /* if TMPDIR is set and not empty, we try that first */
 	 sv = newSVpv(tmpdir, 0);
 	 sv_catpv(sv, tempname + 4);
-	 fd = Perl_my_mkostemp_cloexec(SvPVX(sv), imode);
+	 fd = Perl_my_mkostemp_cloexec(SvPVX(sv), imode | O_VMS_DELETEONCLOSE);
      }
      if (fd < 0) {
 	 SvREFCNT_dec(sv);
 	 sv = NULL;
 	 /* else we try /tmp */
-	 fd = Perl_my_mkostemp_cloexec(tempname, imode);
+	 fd = Perl_my_mkostemp_cloexec(tempname, imode | O_VMS_DELETEONCLOSE);
      }
      if (fd < 0) {
          /* Try cwd */
          sv = newSVpvs(".");
          sv_catpv(sv, tempname + 4);
-         fd = Perl_my_mkostemp_cloexec(SvPVX(sv), imode);
+         fd = Perl_my_mkostemp_cloexec(SvPVX(sv), imode | O_VMS_DELETEONCLOSE);
      }
      umask(old_umask);
      if (fd >= 0) {
@@ -5096,7 +5096,9 @@ PerlIO_tmpfile_flags(int imode)
          f = PerlIO_fdopen(fd, mode);
 	  if (f)
 	       PerlIOBase(f)->flags |= PERLIO_F_TEMP;
+#   ifndef VMS
 	  PerlLIO_unlink(sv ? SvPVX_const(sv) : tempname);
+#   endif
      }
      SvREFCNT_dec(sv);
 #else	/* !HAS_MKSTEMP, fallback to stdio tmpfile(). */
diff --git a/util.c b/util.c
index e6863f6dfe..165d13a39e 100644
--- a/util.c
+++ b/util.c
@@ -5712,6 +5712,11 @@ S_my_mkostemp(char *templte, int flags) {
     STRLEN len = strlen(templte);
     int fd;
     int attempts = 0;
+#ifdef VMS
+    int delete_on_close = flags & O_VMS_DELETEONCLOSE;
+
+    flags &= ~O_VMS_DELETEONCLOSE;
+#endif
 
     if (len < 6 ||
         templte[len-1] != 'X' || templte[len-2] != 'X' || templte[len-3] != 'X' ||
@@ -5725,7 +5730,15 @@ S_my_mkostemp(char *templte, int flags) {
         for (i = 1; i <= 6; ++i) {
             templte[len-i] = TEMP_FILE_CH[(int)(Perl_internal_drand48() * TEMP_FILE_CH_COUNT)];
         }
-        fd = PerlLIO_open3(templte, O_RDWR | O_CREAT | O_EXCL | flags, 0600);
+#ifdef VMS
+        if (delete_on_close) {
+            fd = open(templte, O_RDWR | O_CREAT | O_EXCL | flags, 0600, "fop=dlt");
+        }
+        else
+#endif
+        {
+            fd = PerlLIO_open3(templte, O_RDWR | O_CREAT | O_EXCL | flags, 0600);
+        }
     } while (fd == -1 && errno == EEXIST && ++attempts <= 100);
 
     return fd;
diff --git a/util.h b/util.h
index d8fa3e8396..d9df7b39c6 100644
--- a/util.h
+++ b/util.h
@@ -248,6 +248,17 @@ means arg not present, 1 is empty string/null byte */
 int mkstemp(char*);
 #endif
 
+#ifdef PERL_CORE
+#   if defined(VMS)
+/* only useful for calls to our mkostemp() emulation */
+#       define O_VMS_DELETEONCLOSE 0x40000000
+#       ifdef HAS_MKOSTEMP
+#           error 134221 will need a new solution for VMS
+#       endif
+#   else
+#       define O_VMS_DELETEONCLOSE 0
+#   endif
+#endif
 #if defined(HAS_MKOSTEMP) && defined(PERL_CORE)
 #   define Perl_my_mkostemp(templte, flags) mkostemp(templte, flags)
 #endif
-- 
2.20.1