Implement a built-in function for bursting RFC 934 digests.

* configure.ac: Require Mailutils 2.99.93

* src/prog.c (_cleanup_destroy) allow for clos->cleanup == NULL.
(env_function_cleanup_del): New function.
* src/prog.h (env_function_cleanup_del): New proto.

* mflib/status.mf (e_format): New exception.

* src/builtin/snarf.m4 (MF_CLR_CLEANUP): New macro.
* src/builtin/burst.bi: New source.
* src/builtin/Makefile.am (BI_FILES): Add burst.bi

* src/builtin/body.bi (current_message): Pass MF_MSG_CURRENT
to bi_message_register.
* src/builtin/mbox.bi (mailbox_get_message): Pass MF_MSG_MAILBOX
to bi_message_register.
* src/builtin/msg.bi (drop_current_message)
(bi_get_current_message): Check for MF_MSG_CURRENT
(bi_close_message): Destroy the message if type is MF_MSG_STANDALONE.
(bi_message_register): Change meaning of the last argument.
* src/builtin/msg.h (MF_MSG_MAILBOX)
(MF_MSG_CURRENT,MF_MSG_STANDALONE): New defines.
(mf_message) <mylist>: Remove.
(mf_message) <current>: Rename to type.
* src/builtin/sieve.bi: Fix a bug introduced in 19f41d6c5b.

* NEWS: Document message_burst.
* doc/functions.texi: Restructure the "Message functions" section.

11 files changed, 462 insertions, 19 deletions

diff --git a/src/builtin/.gitignore b/src/builtin/.gitignore
index e72cf081..b82c6f37 100644
--- a/src/builtin/.gitignore
+++ b/src/builtin/.gitignore
@@ -1,5 +1,6 @@
 builtin.h
 body.c
+burst.c
 callout.c
 ctype.c
 curhdr.c
diff --git a/src/builtin/Makefile.am b/src/builtin/Makefile.am
index 8a93e340..c82079c1 100644
--- a/src/builtin/Makefile.am
+++ b/src/builtin/Makefile.am
@@ -20,6 +20,7 @@ noinst_HEADERS = builtin.h  msg.h
 
 BI_FILES=\
  body.bi\
+ burst.bi\
  callout.bi\
  ctype.bi\
  curhdr.bi\
diff --git a/src/builtin/body.bi b/src/builtin/body.bi
index f684801b..be39da6e 100644
--- a/src/builtin/body.bi
+++ b/src/builtin/body.bi
@@ -45,7 +45,7 @@ MF_DEFUN(current_message, NUMBER)
 	rc = bi_get_current_message(env);
 	if (rc < 0) {
 		msg = MF_STREAM_TO_MESSAGE(mstr);
-		rc = bi_message_register(env, NULL, msg, 1);
+		rc = bi_message_register(env, NULL, msg, MF_MSG_CURRENT);
 		MF_ASSERT(rc >= 0,
 			  mfe_failure,
 			  _("no more message slots available"));
diff --git a/src/builtin/burst.bi b/src/builtin/burst.bi
new file mode 100644
index 00000000..dd9b944b
--- /dev/null
+++ b/src/builtin/burst.bi
@@ -0,0 +1,417 @@
+/* This file is part of Mailfromd.             -*- c -*-
+   Copyright (C) 2011 Sergey Poznyakoff
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+/* Functions for converting RFC-934 digests into MIME messages.
+   Largely inspired by MU's mh/burst.c */
+
+#include "msg.h"
+#include "global.h"
+
+/* Minimal length of encapsulation boundary */
+MF_VAR(burst_eb_min_length, NUMBER, SYM_PRECIOUS);
+
+/* Digest messages */
+
+/* Bursting FSA states accoring to RFC 934:
+   
+      S1 ::   "-" S3
+            | CRLF {CRLF} S1
+            | c {c} S2
+
+      S2 ::   CRLF {CRLF} S1
+            | c {c} S2
+
+      S3 ::   " " S2
+            | c S4     ;; the bursting agent should consider the current
+	               ;; message ended.  
+
+      S4 ::   CRLF S5
+            | c S4
+
+      S5 ::   CRLF S5
+            | c {c} S2 ;; The bursting agent should consider a new
+	               ;; message started
+*/
+
+#define S1 1
+#define S2 2
+#define S3 3
+#define S4 4
+#define S5 5
+
+/* Negative state means no write */
+static int transtab[5][256] = {
+/* S1 */ {  S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S1,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2, -S3,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2 },
+/* S2 */ {  S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S1,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2 },
+/* S3 */ { -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S2, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4 },
+/* S4 */ { -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S5, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4, 
+           -S4, -S4, -S4, -S4, -S4, -S4, -S4, -S4 },
+/* S5 */ {  S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2, -S5,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2, 
+            S2,  S2,  S2,  S2,  S2,  S2,  S2,  S2 }
+};
+
+#define F_FIRST  0x01  /* First part of the message (no EB seen so far) */
+#define F_ENCAPS 0x02  /* Within encapsulated part */
+
+struct burst_stream {
+	mu_mime_t mime;
+	mu_stream_t stream;  /* Output stream */
+	int flags;           /* See F_ flags above */
+	size_t partno;       /* Number of the part within the message */
+};
+
+static inline void
+finish_stream(eval_environ_t env, struct burst_stream *bs)
+{
+	if (bs->stream) {
+		mu_message_t msg;
+      
+		mu_stream_seek(bs->stream, 0, SEEK_SET, NULL);
+		msg = MF_STREAM_TO_MESSAGE(bs->stream);
+		mu_mime_add_part(bs->mime, msg);
+		mu_message_unref(msg);
+		bs->stream = 0;
+		bs->partno++;
+		bs->flags &= ~F_FIRST;
+	}
+}  
+
+static inline void
+flush_stream(eval_environ_t env, struct burst_stream *bs,
+	     char *buf, size_t size)
+{
+	int rc;
+
+	if (size == 0)
+		return;
+	if (!bs->stream) {
+		rc = mu_temp_file_stream_create(&bs->stream, NULL, 0);
+		MF_ASSERT(rc == 0,
+			  mfe_failure,
+			  _("Cannot open temporary file: %s"),
+			  mu_strerror(rc));
+		/*
+		mu_stream_printf(bs->stream, "X-Burst-Part: 0 %lu %02x\n",
+				 (unsigned long) bs->partno, bs->flags);
+		if (!bs->flags)
+			mu_stream_write(bs->stream, "\n", 1, NULL);
+		*/
+	}
+
+	rc = mu_stream_write(bs->stream, buf, size, NULL);
+	MF_ASSERT(rc == 0,
+		  mfe_failure,
+		  _("error writing temporary stream: %s"),
+		  mu_strerror(rc));
+}
+
+static void
+burst_stream_cleanup(void *data)
+{
+	struct burst_stream *bs = data;
+	mu_stream_unref(bs->stream);
+	mu_mime_destroy(&bs->mime);
+	free(bs);
+}
+
+/* Burst an RFC 934 digest.  Return 0 if OK, 1 if the message is not
+   a valid digest.
+   FIXME: On errors, cleanup and return -1.
+*/
+int
+burst_digest(eval_environ_t env, mu_mime_t mime, mu_message_t msg)
+{
+	int rc;
+	mu_body_t body;
+	mu_stream_t is;
+	unsigned char c;
+	size_t n;
+	int state = S1;
+	int eb_length = 0;
+	struct burst_stream *bs;
+	int result = 0;
+
+	int eb_min_length = (int) MF_VAR_REF(burst_eb_min_length);
+	if (eb_min_length <= 0)
+		eb_min_length = 1;
+
+	bs = xmalloc(sizeof(*bs));
+	bs->mime = mime;
+	bs->stream = NULL;
+	bs->flags = F_FIRST;
+	bs->partno = 1;
+	MF_DCL_CLEANUP(bs, burst_stream_cleanup);
+		
+	rc = mu_message_get_body(msg, &body);
+	MF_ASSERT(rc == 0,
+		  mfe_failure,
+		  "mu_message_get_body: %s",
+		  mu_strerror(rc));
+	
+	rc = mu_body_get_streamref(body, &is);
+	MF_ASSERT(rc == 0,
+		  mfe_failure,
+		  "mu_body_get_streamref: %s",
+		  mu_strerror(rc));
+	
+	while (mu_stream_read(is, &c, 1, &n) == 0 && n == 1) {
+		int newstate = transtab[state - 1][c];
+		int silent = 0;
+      
+		if (newstate < 0) {
+			newstate = -newstate;
+			silent = 1;
+		}
+
+		if (state == S1) {
+			/* GNU extension: check if we have seen enough
+			   dashes to constitute a valid encapsulation
+			   boundary. */
+			if (newstate == S3) {
+				eb_length++;
+				if (eb_length < eb_min_length)
+					continue; /* Ignore state change */
+				if (eb_min_length > 1) {
+					newstate = S4;
+					finish_stream(env, bs);
+					bs->flags ^= F_ENCAPS;
+				}
+			} else
+				for (; eb_length; eb_length--)
+					flush_stream(env, bs, "-", 1);
+			eb_length = 0;
+		} else if (state == S5 && newstate == S2) {
+			/* As the automaton traverses from state S5 to S2, the
+			   bursting agent should consider a new message started
+			   and output the first character. */
+			finish_stream(env, bs);
+		} else if (state == S3 && newstate == S4) {
+			/* As the automaton traverses from state S3 to S4, the
+			   bursting agent should consider the current message
+			   ended. */
+			finish_stream(env, bs);
+			bs->flags ^= F_ENCAPS;
+		}
+		state = newstate;
+		if (!silent)
+			flush_stream(env, bs, (char*)&c, 1);
+	}
+	mu_stream_destroy(&is);
+
+	if (bs->flags == F_FIRST) {
+		mu_stream_destroy(&bs->stream);
+		result = 1;
+	} else {
+		if (bs->stream) {
+			mu_off_t size = 0;
+			mu_stream_size(bs->stream, &size);
+			if (size)
+				finish_stream(env, bs);
+			else
+				mu_stream_destroy(&bs->stream);
+		}
+		bs->mime = NULL;
+	}
+	MF_CLEANUP(bs);
+	return result;
+}
+
+MF_DEFUN(message_burst, NUMBER, NUMBER nmsg)
+{
+	int rc;
+	mu_message_t msg;
+	mu_mime_t mime;
+	
+	msg = bi_message_from_descr(env, nmsg);
+	rc = mu_mime_create(&mime, NULL, 0);
+	MF_ASSERT(rc == 0,
+		  mfe_failure,
+		  _("mu_mime_create: %s"),
+		  mu_strerror(rc));
+	rc = burst_digest(env, mime, msg);
+	MF_ASSERT(rc == 0,
+		  mfe_format,
+		  _("message is not a RFC-934 digest"));
+	rc = mu_mime_to_message(mime, &msg);
+	mu_mime_unref(mime);
+	MF_ASSERT(rc == 0,
+		  mfe_failure,
+		  _("mu_mime_get_message: %s"),
+		  mu_strerror(rc));
+	rc = bi_message_register(env, NULL, msg, MF_MSG_STANDALONE);
+	if (rc < 0) {
+		mu_message_destroy(&msg, mu_message_get_owner(msg));
+		MF_THROW(mfe_failure,
+			 _("no more message slots available"));
+	}
+	MF_RETURN(rc);
+}
+END
+
+MF_INIT
diff --git a/src/builtin/mbox.bi b/src/builtin/mbox.bi
index 5ac5b794..03b2227e 100644
--- a/src/builtin/mbox.bi
+++ b/src/builtin/mbox.bi
@@ -223,7 +223,7 @@ MF_DEFUN(mailbox_get_message, NUMBER, NUMBER nmbx, NUMBER msgno)
 		  mfe_failure,
 		  "%s",
 		  mu_strerror(rc));
-	rc = bi_message_register(env, mp->msglist, msg, 0);
+	rc = bi_message_register(env, mp->msglist, msg, MF_MSG_MAILBOX);
 	MF_ASSERT(rc >= 0,
 		  mfe_failure,
 		  _("no more message slots available"));
diff --git a/src/builtin/msg.bi b/src/builtin/msg.bi
index aa25b1f4..369d5e30 100644
--- a/src/builtin/msg.bi
+++ b/src/builtin/msg.bi
@@ -48,7 +48,7 @@ drop_current_message(void *data)
 	int i;
 	struct mf_message *tab = data;
 	for (i = 0; i < nmsgs; i++)
-		if (tab[i].msg && tab[i].current) {
+		if (tab[i].msg && tab[i].type == MF_MSG_CURRENT) {
 			bi_close_message(&tab[i]);
 			break;
 		}
@@ -79,10 +79,9 @@ bi_close_message(struct mf_message *mp)
 	if (mp->msg) {
 		mu_stream_destroy(&mp->mstr);
 		mu_stream_destroy(&mp->bstr);
-		if (mp->mylist) {
-			mu_list_remove(mp->mylist, mp);
-			mu_list_destroy(&mp->mylist);
-		}
+		if (mp->type == MF_MSG_STANDALONE)
+			mu_message_destroy(&mp->msg,
+					   mu_message_get_owner(mp->msg));
 		mu_list_do(mp->msglist, do_msg_close, NULL);
 		mu_list_destroy(&mp->msglist);
 		free(mp->buf);
@@ -92,15 +91,14 @@ bi_close_message(struct mf_message *mp)
 
 int
 bi_message_register(eval_environ_t env,
-		    mu_list_t msglist, mu_message_t msg, int current)
+		    mu_list_t msglist, mu_message_t msg, int type)
 {
 	struct mf_message *msgtab = MF_GET_DATA;
 	int idx = find_slot(msgtab);
 	if (idx >= 0) {
 		struct mf_message *mp = msgtab + idx;
 		mp->msg = msg;
-		mp->current = current;
-		mu_list_create(&mp->mylist);
+		mp->type = type;
 		mu_list_create(&mp->msglist);
 		if (msglist)
 			mu_list_append(msglist, mp);
@@ -114,7 +112,7 @@ bi_get_current_message(eval_environ_t env)
 	int i;
 	struct mf_message *tab = MF_GET_DATA;
 	for (i = 0; i < nmsgs; i++)
-		if (tab[i].msg && tab[i].current)
+		if (tab[i].msg && tab[i].type == MF_MSG_CURRENT)
 			return i;
 	return -1;
 }
@@ -413,7 +411,7 @@ MF_DEFUN(message_get_part, NUMBER, NUMBER nmsg, NUMBER idx)
 		  mfe_failure,
 		  "%s",
 		  mu_strerror(rc));
-	rc = bi_message_register(env, mp->msglist, msg, 0);
+	rc = bi_message_register(env, mp->msglist, msg, MF_MSG_MAILBOX);
 	MF_ASSERT(rc >= 0,
 		  mfe_failure,
 		  _("no more message slots available"));
@@ -593,7 +591,7 @@ MF_DEFUN(message_from_stream, NUMBER, NUMBER fd, OPTIONAL,
 
 	msg = MF_STREAM_TO_MESSAGE(src);
 
-	rc = bi_message_register(env, NULL, msg, 0);
+	rc = bi_message_register(env, NULL, msg, MF_MSG_STANDALONE);
 	if (rc < 0) {
 		mu_message_destroy(&msg, mu_message_get_owner(msg));
 		MF_THROW(mfe_failure,
diff --git a/src/builtin/msg.h b/src/builtin/msg.h
index 05052f85..87fcfdac 100644
--- a/src/builtin/msg.h
+++ b/src/builtin/msg.h
@@ -22,6 +22,10 @@ struct mf_mbox {
 	mu_list_t /* of struct mf_message */ msglist;
 };
 
+#define MF_MSG_MAILBOX    0
+#define MF_MSG_CURRENT    1
+#define MF_MSG_STANDALONE 2
+
 struct mf_message {
 	mu_message_t msg;
 	mu_stream_t mstr;
@@ -31,13 +35,13 @@ struct mf_message {
 	mu_stream_t bstr;
 	char *buf;
 	size_t bufsize;
-	int current;
-	mu_list_t /* of struct mf_message */ mylist, msglist;
+	int type;
+	mu_list_t /* of struct mf_message */ msglist;
 };
 
 void bi_close_message(struct mf_message *msg);
 int bi_message_register(eval_environ_t env, mu_list_t list, mu_message_t msg,
-			int current);
+			int type);
 int bi_get_current_message(eval_environ_t env);
 mu_message_t bi_message_from_descr(eval_environ_t env, int md);
 
diff --git a/src/builtin/sieve.bi b/src/builtin/sieve.bi
index 3b4f5879..528c8762 100644
--- a/src/builtin/sieve.bi
+++ b/src/builtin/sieve.bi
@@ -92,16 +92,18 @@ MF_DEFUN(sieve, NUMBER, NUMBER nmsg, STRING script, OPTIONAL, NUMBER flags,
 
 	mu_sieve_set_data(mach, env);
 
-	if (f & MF_SIEVE_LOG)
-		mu_sieve_set_logger(mach, _sieve_text_action_log);
 	if (f & MF_SIEVE_TEXT) {
 		struct locus locus;
 
 		env_get_locus(env, &locus);
+		if (f & MF_SIEVE_LOG)
+			mu_sieve_set_logger(mach, _sieve_text_action_log);
 		rc = mu_sieve_compile_buffer(mach, script, strlen(script),
 					     MF_OPTVAL(file, locus.file),
 					     MF_OPTVAL(line, locus.line));
 	} else {
+		if (f & MF_SIEVE_LOG)
+			mu_sieve_set_logger(mach, _sieve_file_action_log);
 		rc = mu_sieve_compile(mach, script);
 	}
 
diff --git a/src/builtin/snarf.m4 b/src/builtin/snarf.m4
index b07ee7c8..53dbfc9c 100644
--- a/src/builtin/snarf.m4
+++ b/src/builtin/snarf.m4
@@ -681,6 +681,9 @@ m4_define([<__mf_dataseg>])m4_dnl
 m4_define([<MF_DCL_CLEANUP>],[<env_function_cleanup_add(env, $1, m4_dnl
 m4_ifelse($2,,NULL,$2))>])
 
+/* MF_CLR_CLEANUP(ptr) */
+m4_define([<MF_CLR_CLEANUP>],[<env_function_cleanup_del(env, $1)>])
+
 /* MF_CLEANUP(ptr) */
 m4_define([<MF_CLEANUP>],[<env_function_cleanup_flush(env, $1)>])
 
diff --git a/src/prog.c b/src/prog.c
index 940e9aa1..89482813 100644
--- a/src/prog.c
+++ b/src/prog.c
@@ -423,7 +423,8 @@ static void
 _cleanup_destroy(void *item)
 {
 	struct environ_cleanup_closure *clos = item;
-	clos->cleanup(clos->data);
+	if (clos->cleanup)
+		clos->cleanup(clos->data);
 }
 
 static void
@@ -447,6 +448,21 @@ env_function_cleanup_flush(eval_environ_t env, void *ptr)
 }			
 
 void
+env_function_cleanup_del(eval_environ_t env, void *ptr)
+{
+	int rc;
+	struct environ_cleanup_closure clos, *cptr;
+
+	clos.data = ptr;
+
+	rc = mu_list_locate(env->cleanup_list, &clos, (void**)cptr);
+	if (rc == 0) {
+		cptr->cleanup = NULL;
+		mu_list_remove(env->cleanup_list, &clos);
+	}
+}
+
+void
 env_function_cleanup_add(eval_environ_t env, void *data,
 			 void (*func)(void *))
 {
diff --git a/src/prog.h b/src/prog.h
index 40f91f45..16169364 100644
--- a/src/prog.h
+++ b/src/prog.h
@@ -69,6 +69,7 @@ void env_free_captured(eval_environ_t env);
 
 void env_function_cleanup_add(eval_environ_t env, void *data,
 			      void (*func)(void *));
+void env_function_cleanup_del(eval_environ_t env, void *data);
 void env_function_cleanup_flush(eval_environ_t env, void *ptr);
 
 void ensure_initialized_variable(const char *name, struct value *val);