buffer: Change buf_prepend and buf_advance to accept ssize_t for length

We already have tests to make sure the value is sane.
Changing the argument to ssize_t allows to use it in
more places without needing to do a cast before the
checks.

Change-Id: I123002255b37160d48ef6481f68a89d03073236b
Signed-off-by: Frank Lichtenheld <[email protected]>
Acked-by: Gert Doering <[email protected]>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1437
Message-Id: <[email protected]>
URL: https://www.mail-archive.com/[email protected]/msg35099.html
Signed-off-by: Gert Doering <[email protected]>

Author: flichtenheld

src/openvpn/buffer.c

@@ -789,7 +789,7 @@ buf_string_compare_advance(struct buffer *src, const char *match)
 {
     if (buf_string_match_head_str(src, match))
     {
-        buf_advance(src, (int)strlen(match));
+        buf_advance(src, strlen(match));
         return true;
     }
     else
@@ -1312,7 +1312,7 @@ buffer_list_pop(struct buffer_list *ol)
 }
 
 void
-buffer_list_advance(struct buffer_list *ol, int n)
+buffer_list_advance(struct buffer_list *ol, ssize_t n)
 {
     if (ol->head)
     {

src/openvpn/buffer.h

@@ -601,26 +601,26 @@ buf_inc_len(struct buffer *buf, int inc)
  */
 
 static inline uint8_t *
-buf_prepend(struct buffer *buf, int size)
+buf_prepend(struct buffer *buf, ssize_t size)
 {
     if (!buf_valid(buf) || size < 0 || size > buf->offset)
     {
         return NULL;
     }
-    buf->offset -= size;
-    buf->len += size;
+    buf->offset -= (int)size;
+    buf->len += (int)size;
     return BPTR(buf);
 }
 
 static inline bool
-buf_advance(struct buffer *buf, int size)
+buf_advance(struct buffer *buf, ssize_t size)
 {
     if (!buf_valid(buf) || size < 0 || buf->len < size)
     {
         return false;
     }
-    buf->offset += size;
-    buf->len -= size;
+    buf->offset += (int)size;
+    buf->len -= (int)size;
     return true;
 }
 
@@ -1187,7 +1187,7 @@ struct buffer_entry *buffer_list_push_data(struct buffer_list *ol, const void *d
  */
 struct buffer *buffer_list_peek(struct buffer_list *ol);
 
-void buffer_list_advance(struct buffer_list *ol, int n);
+void buffer_list_advance(struct buffer_list *ol, ssize_t n);
 
 void buffer_list_pop(struct buffer_list *ol);
 

src/openvpn/ps.c

@@ -596,7 +596,7 @@ proxy_connection_io_send(struct proxy_connection *pc, int *bytes_sent)
         {
             dmsg(D_PS_PROXY_DEBUG, "PORT SHARE PROXY: partial write[%d], tried=%d got=%zd", (int)sd,
                  pc->buf.len, status);
-            buf_advance(&pc->buf, (int)status);
+            buf_advance(&pc->buf, status);
             return IOSTAT_EAGAIN_ON_WRITE;
         }
         else