Paul Bagyenda wrote:
Hi,
Mbuni MMSC/MMS VAS Gateway makes heavy use of Kannel's GWLIB,
which has resulted partly in some patches to Kannel from our side, to
take care of missing stuff (or stuff we thought looked faulty). Many
of these are now merged into CVS.
One area we've been talking about for a while now is the Kannel
MIME module. With Stipe's help we've managed to narrow down our issues
to one problem: The fact that the layout of the MIMEEntity structure
is exposed in the header file. The potential problems are subtle. In
our case we tripped on the following problem: If you have a multi-part
MIME object that you have constructed manually (as is done for
instance in the Mbuni code that converts an MMS into an MM7/SOAP
message), and you want to extract its header (mime_entity_headers())
and then its body (mime_entity_body()), you end up with a wrong or
missing boundary element for the content type in the header. The
result is that header/body can no longer be combined and parsed!
In discussions with Stipe, it looks like whichever way you cut it,
this kind of problem would arise, as long as users can muck around
with the internal structure of a MIMEEntity. Solution: Hide it and
add additional helper functions for manipulating the structure.
Suggested solution attached as a patch against CVS.
Thanks a lot Paul,
This looks good. I have revised the patch (attached) in terms of
CodingStyle and some slight logic change.
Can you please review and comment if this is still what we want?
Comments from others please... I'm +1 on commiting the suggersted
solution to cvs in order to solve the direct access problematic of the
MIMEEntity object.
Stipe
-------------------------------------------------------------------
Kölner Landstrasse 419
40589 Düsseldorf, NRW, Germany
tolj.org system architecture Kannel Software Foundation (KSF)
http://www.tolj.org/ http://www.kannel.org/
mailto:st_{at}_tolj.org mailto:stolj_{at}_kannel.org
-------------------------------------------------------------------
------------------------------------------------------------------------
### Eclipse Workspace Patch 1.0
#P gateway-cvs
Index: gwlib/mime.c
===================================================================
RCS file: /home/cvs/gateway/gwlib/mime.c,v
retrieving revision 1.12
diff -u -r1.12 mime.c
--- gwlib/mime.c 9 Dec 2005 02:41:14 -0000 1.12
+++ gwlib/mime.c 6 Feb 2006 01:15:35 -0000
@@ -75,6 +75,18 @@
/********************************************************************
+ * Internal data structure types
+ */
+
+struct MIMEEntity {
+ List *headers;
+ List *multiparts;
+ Octstr *body;
+ struct MIMEEntity *start; /* in case multipart/related */
+};
+
+
+/********************************************************************
* Creation and destruction routines.
*/
@@ -150,20 +162,61 @@
}
+/*
+ * This function checks that there is a boundary parameter in the headers
+ * for a multipart MIME object. If not, it is inserted and passed back to
caller
+ * in the variable boundary_elem.
+ */
+static void fix_boundary_element(List *headers, Octstr **boundary_elem)
+{
+ Octstr *value, *boundary;
+
+ if (headers == NULL)
+ return;
+
+ /*
+ * Check if we have an boundary parameter already in the
+ * Content-Type header. If no, add one, otherwise parse which one
+ * we should use.
+ * XXX this can be abstracted as function in gwlib/http.[ch].
+ */
+ value = http_header_value(headers, octstr_imm("Content-Type"));
+ boundary = http_get_header_parameter(value, octstr_imm("boundary"));
+ if (boundary == NULL) {
+ boundary = octstr_format("_boundary_%d_%ld_%c_%c_bd%d",
+ random(), (long)time(NULL), 'A' + (random()%26),
+ 'a'+(random() % 26), random());
+ octstr_format_append(value, "; boundary=%S", boundary);
+
+ http_header_remove_all(headers, "Content-Type");
+ http_header_add(headers, "Content-Type", octstr_get_cstr(value));
+ http_header_add(headers, "MIME-Version", "1.0");
+ }
+ octstr_destroy(value);
+
+ /* if we got a NULL'ed value, throw away, otherwise return */
+ if (boundary_elem)
+ *boundary_elem = boundary;
+ else
+ octstr_destroy(boundary);
+}
+
+
/********************************************************************
* Mapping function from other data types, mainly Octstr and HTTP.
*/
static Octstr *mime_entity_to_octstr_real(MIMEEntity *m, unsigned int level)
{
- Octstr *mime, *value, *boundary;
+ Octstr *mime, *boundary;
List *headers;
long i;
gw_assert(m != NULL && m->headers != NULL);
+ boundary = NULL;
mime = octstr_create("");
-
+
/*
* First of all check if we have further MIME entity dependencies,
* which means we have further MIMEEntities in our m->multiparts
@@ -181,26 +234,9 @@
goto finished;
}
- /*
- * Check if we have an boundary parameter already in the
- * Content-Type header. If no, add one, otherwise parse which one
- * we should use.
- * XXX this can be abstracted as function in gwlib/http.[ch].
- */
+ /* This call ensures boundary exists, and returns it */
+ fix_boundary_element(m->headers, &boundary);
headers = http_header_duplicate(m->headers);
- value = http_header_value(headers, octstr_imm("Content-Type"));
- boundary = http_get_header_parameter(value, octstr_imm("boundary"));
- if (boundary == NULL) {
- boundary = octstr_format("_boundary_%d_%ld_%c_%c_bd%d",
- random(), (long)time(NULL), 'A' + (random()%26),
- 'a'+(random() % 26), random());
- octstr_format_append(value, "; boundary=%S", boundary);
-
- http_header_remove_all(headers, "Content-Type");
- http_header_add(headers, "Content-Type", octstr_get_cstr(value));
- http_header_add(headers, "MIME-Version", "1.0");
- }
- octstr_destroy(value);
/* headers */
for (i = 0; i < gwlist_len(headers); i++) {
@@ -229,8 +265,10 @@
/* add the last boundary statement, but hive an EOL
* if we are on the top of the recursion stack. */
+
/* if (level > 0) */
- octstr_append(mime, octstr_imm("\r\n"));
+ octstr_append(mime, octstr_imm("\r\n"));
+
octstr_append(mime, octstr_imm("\r\n--"));
octstr_append(mime, boundary);
octstr_append(mime, octstr_imm("--\r\n"));
@@ -238,7 +276,6 @@
octstr_destroy(boundary);
finished:
-
return mime;
}
@@ -409,6 +446,9 @@
gw_assert(m != NULL && m->headers != NULL);
+ /* Need a fixup before hand over. */
+ fix_boundary_element(m->headers, NULL);
+
headers = http_header_duplicate(m->headers);
return headers;
@@ -423,6 +463,10 @@
gw_assert(m != NULL && m->headers != NULL);
+ /* For non-multipart, return body directly. */
+ if (mime_entity_num_parts(m) == 0)
+ return octstr_duplicate(m->body);
+
os = mime_entity_to_octstr(m);
context = parse_context_create(os);
e = mime_entity_create();
@@ -447,6 +491,108 @@
}
+MIMEEntity *mime_entity_duplicate(MIMEEntity *e)
+{
+ MIMEEntity *copy = mime_entity_create();
+ int i, n;
+
+ mime_replace_headers(copy, e->headers);
+ copy->body = e->body ? octstr_duplicate(e->body) : NULL;
+
+ for (i = 0, n = gwlist_len(e->multiparts); i < n; i++)
+ gwlist_append(copy->multiparts,
+ mime_entity_duplicate(gwlist_get(e->multiparts, i)));
+ return copy;
+}
+
+
+void mime_replace_headers(MIMEEntity *e, List *headers)
+{
+ gw_assert(e != NULL);
+ gw_assert(headers != NULL);
+
+ http_destroy_headers(e->headers);
+ e->headers = http_header_duplicate(headers);
+}
+
+
+int mime_entity_num_parts(MIMEEntity *e)
+{
+ gw_assert(e != NULL);
+
+ return (e->multiparts ? gwlist_len(e->multiparts) : 0);
+}
+
+
+/*
+ * Append a new part to list of body parts, copy is added.
+ * Note that if it was not multipart, this action makes it so!
+ */
+void mime_entity_add_part(MIMEEntity *e, MIMEEntity *part)
+{
+ gw_assert(e != NULL);
+ gw_assert(part != NULL);
+
+ gwlist_append(e->multiparts, mime_entity_duplicate(part));
+}
+
+
+MIMEEntity *mime_entity_get_part(MIMEEntity *e, int i)
+{
+ MIMEEntity *m;
+ gw_assert(e != NULL);
+ gw_assert(i >= 0);
+ gw_assert(i < gwlist_len(e->multiparts));
+
+ m = gwlist_get(e->multiparts, i);
+ gw_assert(m);
+ return mime_entity_duplicate(m);
+}
+
+
+void mime_entity_remove_part(MIMEEntity *e, int i)
+{
+ MIMEEntity *m;
+
+ gw_assert(e != NULL);
+ gw_assert(i >= 0);
+ gw_assert(i < gwlist_len(e->multiparts));
+
+
+ m = gwlist_get(e->multiparts, i);
+ gwlist_delete(e->multiparts, i, 1);
+
+ mime_entity_destroy(m);
+}
+
+
+void mime_entity_replace_part(MIMEEntity *e, int i, MIMEEntity *newpart)
+{
+
+ MIMEEntity *m;
+
+ gw_assert(e != NULL);
+ gw_assert(i >= 0);
+ gw_assert(i < gwlist_len(e->multiparts));
+
+ m = gwlist_get(e->multiparts, i);
+ gwlist_delete(e->multiparts, i, 1);
+ gwlist_insert(e->multiparts, i, mime_entity_duplicate(newpart));
+
+ mime_entity_destroy(m);
+}
+
+
+void mime_entity_set_body(MIMEEntity *e, Octstr *body)
+{
+ gw_assert(e != NULL);
+ gw_assert(body != NULL);
+
+ octstr_destroy(e->body);
+ e->body = octstr_duplicate(body);
+}
+
+
/********************************************************************
* Routines for debugging purposes.
*/
Index: gwlib/mime.h
===================================================================
RCS file: /home/cvs/gateway/gwlib/mime.h,v
retrieving revision 1.8
diff -u -r1.8 mime.h
--- gwlib/mime.h 11 Feb 2005 15:35:48 -0000 1.8
+++ gwlib/mime.h 6 Feb 2006 01:15:35 -0000
@@ -90,21 +90,54 @@
#include "gwlib/gwlib.h"
-
-/* Define an generic MIME entity structure to be
- * used for MIME multipart parsing. */
-typedef struct MIMEEntity {
- List *headers;
- List *multiparts;
- Octstr *body;
- struct MIMEEntity *start; /* in case multipart/related */
-} MIMEEntity;
+typedef struct MIMEEntity MIMEEntity;
/* create and destroy MIME multipart entity */
MIMEEntity *mime_entity_create(void);
void mime_entity_destroy(MIMEEntity *e);
+/*
+ * Make a copy of a MIME object.
+ */
+MIMEEntity *mime_entity_duplicate(MIMEEntity *e);
+
+/*
+ * Replace top-level MIME headers: Old ones removed completetly
+ */
+void mime_replace_headers(MIMEEntity *e, List *headers);
+
+/*
+ * Get number of body parts. Returns 0 if this is not
+ * a multipart object.
+ */
+int mime_entity_num_parts(MIMEEntity *e);
+
+/*
+ * Append a new part to list of body parts. Copy is added.
+ */
+void mime_entity_add_part(MIMEEntity *e, MIMEEntity *part);
+
+/*
+ * Get part i in list of body parts. Copy is returned.
+ */
+MIMEEntity *mime_entity_get_part(MIMEEntity *e, int i);
+
+/*
+ * Replace part i in list of body parts. Old one will be deleted.
+ */
+void mime_entity_replace_part(MIMEEntity *e, int i, MIMEEntity *newpart);
+
+/*
+ * Remove part i in list of body parts.
+ */
+void mime_entity_remove_part(MIMEEntity *e, int i);
+
+/*
+ * Change body element of non-multipart entity.
+ */
+void mime_entity_set_body(MIMEEntity *e, Octstr *body);
+
/*
* Parse the given Octstr that contains a normative text representation
* of the MIME multipart document into our representation strucuture.
