From: Walter Doekes <walter+asterisk@wjd.nu>
Date: Thu, 2 Jul 2015 11:10:59 +0000 (+0200)
Subject: rtp_engine: Skip useless self-assignment in ast_rtp_engine_unload_format.
X-Git-Tag: 13.5.0-rc1~62^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b835312b4c2e1fcd3f7efb5ae45a0c4d10d4d5f7;p=thirdparty%2Fasterisk.git

rtp_engine: Skip useless self-assignment in ast_rtp_engine_unload_format.

When running valgrind on Asterisk, it complained about:

    ==32423== Source and destination overlap in memcpy(0x85a920, 0x85a920, 304)
    ==32423==    at 0x4C2F71C: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/...)
    ==32423==    by 0x55BA91: ast_rtp_engine_unload_format (rtp_engine.c:2292)
    ==32423==    by 0x4EEFB7: ast_format_attr_unreg_interface (format.c:1437)

The code in question is a struct assignment, which may be performed by
memcpy as a compiler optimization. It is changed to only copy the struct
contents if source and destination are different.

ASTERISK-25219 #close

Change-Id: I6d3546c326b03378ca8e9b8cefd41c16e0088b9a
---

diff --git a/main/rtp_engine.c b/main/rtp_engine.c
index e09dcb88c5..2d61c89b6a 100644
--- a/main/rtp_engine.c
+++ b/main/rtp_engine.c
@@ -1798,7 +1798,9 @@ int ast_rtp_engine_unload_format(struct ast_format *format)
 			rtp_engine_mime_type_cleanup(x);
 			continue;
 		}
-		ast_rtp_mime_types[y] = ast_rtp_mime_types[x];
+		if (x != y) {
+			ast_rtp_mime_types[y] = ast_rtp_mime_types[x];
+		}
 		y++;
 	}
 	mime_types_len = y;