From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 11 Oct 2019 23:30:02 +0000 (+0100)
Subject: test: udp-preload: Proof of concept wrapping (2)
X-Git-Tag: v0.5.0~118
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=06a209482573a4f259803517fcc22b5721309d4a;p=secnet.git

test: udp-preload: Proof of concept wrapping (2)

  gcc -D_REENTRANT -fPIC -c udp-preload.c && \
  ld -shared -soname foo.so.1 udp-preload.o -o udp-preload.so -ldl -lc

produces a library with which

  LD_PRELOAD=test/udp-preload.so test/invoke

still works.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/test/udp-preload.c b/test/udp-preload.c
index 8c7d18c..ba9b7a4 100644
--- a/test/udp-preload.c
+++ b/test/udp-preload.c
@@ -72,7 +72,7 @@ WRAPS(DEF_OLD)
 #define WRAP(fn) int fn(fn##_args)
 
 WRAP(socket) {
-    errno=EMSGSIZE;  return -1;
+    return old_socket(domain,type,protocol);
 }
 
 #if 0