From 13b32a48b15d0fcfc3b8b9e0691a782f590e165f Mon Sep 17 00:00:00 2001
From: tyrolyean <tyrolyean@tyrolyean.net>
Date: Wed, 29 Apr 2020 03:00:12 +0200
Subject: [PATCH] Added boundary retrieval

Signed-off-by: tyrolyean <tyrolyean@tyrolyean.net>
---
 include/attach.h |  3 ++-
 include/mail.h   |  2 ++
 include/tools.h  |  2 ++
 src/attach.c     | 24 ++++++++++++++++++++++--
 src/tools.c      | 37 +++++++++++++++++++++++++++++++++++++
 5 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/include/attach.h b/include/attach.h
index 599fceb..4db4ac2 100644
--- a/include/attach.h
+++ b/include/attach.h
@@ -25,7 +25,8 @@
 
 struct email_t mail_from_text(char* message, size_t length);
 void redetect_body_head(struct email_t* mail);
-
+void unravel_multipart_mail(struct email_t* mail, char* boundary,
+	size_t boundary_len);
 
 char* attach_files(char* message, size_t len);
 
diff --git a/include/mail.h b/include/mail.h
index c0ea07b..328e9fa 100644
--- a/include/mail.h
+++ b/include/mail.h
@@ -39,4 +39,6 @@ struct email_t{
 int append_header(struct email_t* mail, const char* key, const char* value);
 int append_to_header(struct email_t* mail, const char* pair);
 
+#define MULTIPART_MIME "multipart/"
+
 #endif /* MAIL_H */
diff --git a/include/tools.h b/include/tools.h
index 75c2f4e..60494eb 100644
--- a/include/tools.h
+++ b/include/tools.h
@@ -29,4 +29,6 @@ char* search_header_key(struct email_t* mail, const char* key);
 char* get_value_from_key(size_t* val_len, size_t key_offset, 
 	struct email_t* mail);
 
+char* get_multipart_boundary(char* content_type, size_t content_len,
+	size_t* boundary_len);
 #endif /* TOOLS_H */
diff --git a/src/attach.c b/src/attach.c
index de1659f..54c481a 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -48,8 +48,21 @@ struct email_t mail_from_text(char* message, size_t length){
 		char * mime_type = get_value_from_key(&value_length, 
 			cont_type - mail.message, &mail);
 		if(mime_type != NULL){
-			printf("Found message mime type: [%.*s]\n",
-				(int)value_length, mime_type);
+			if(strncasecmp(mime_type, MULTIPART_MIME, 
+				strlen(MULTIPART_MIME)) == 0){
+				/* We have multiple messages cramped inside this
+				 * one. Let's unravel em!
+				 */
+				 size_t bd_len = 0;
+				char* bd = get_multipart_boundary(
+					mime_type, value_length, &bd_len);
+				if(bd != NULL){
+					printf("Received boundary: [%.*s]\n",
+						(int)bd_len, bd);
+				}
+				unravel_multipart_mail(&mail, bd, bd_len);
+
+			}
 		}
 	}
 
@@ -93,6 +106,13 @@ void redetect_body_head(struct email_t* mail){
 	
 }
 
+void unravel_multipart_mail(struct email_t* mail, char* boundary, 
+	size_t boundary_len){
+
+	return;
+
+}
+
 /* Message is required to be a null terminated string, length is the mail body.
  * One may leave something behind the body. len is without the '\0'
  * Attempts to replace files inside the email with links to it on a webserver
diff --git a/src/tools.c b/src/tools.c
index 7657cc7..f076ddf 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -113,3 +113,40 @@ char* get_value_from_key(size_t* val_len, size_t key_offset,
 
 	return val;
 }
+
+char* get_multipart_boundary(char* content_type, size_t content_len, 
+	size_t* boundary_len){
+
+	if(content_type == NULL || boundary_len == NULL){
+		return NULL;
+	}
+	
+	char* bd = "boundary";
+	char* boundary_begin = NULL;
+	size_t bd_len = strlen(bd);
+	long boundary_offset = -1;
+
+	for(size_t i = 0; i < (content_len - bd_len);i++){
+		if(strncasecmp(&content_type[i], bd, bd_len) == 0){
+			boundary_offset = i+bd_len;
+			break;
+		}
+	}
+	
+	if(boundary_offset < 0){
+		*boundary_len = 0;
+		return NULL;
+	}
+	
+	for(size_t i = boundary_offset; i < content_len;i++){
+		if(content_type[i] == '"' && boundary_begin == NULL){
+			boundary_begin = &content_type[i+1];
+		}else  if(content_type[i] == '"'){
+			*boundary_len = &content_type[i] - boundary_begin ;
+			return boundary_begin;
+		}
+	}
+	
+	*boundary_len = 0;
+	return NULL;
+}