MemorySanitizer patch for libaio

libaio-msan.patch

x86_64 only patch to build libaio under MemorySanitzer. Based against libaio git repo from
https://git.fedorahosted.org/cgit/libaio.git/ and using the information provided by Evgeniy Stepanov in
https://github.com/google/sanitizers/issues/688#issuecomment-225403581 .

diff --git a/src/Makefile b/src/Makefile
index eadb336..c839c9c 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2,8 +2,8 @@ prefix=/usr
 includedir=$(prefix)/include
 libdir=$(prefix)/lib
 
-CFLAGS ?= -g -fomit-frame-pointer -O2
-CFLAGS += -nostdlib -nostartfiles -Wall -I. -fPIC
+CFLAGS ?= -g -fomit-frame-pointer -O2 -fsanitize=memory
+CFLAGS += -nostdlib -nostartfiles -Wall -I. -fPIC -fsanitize=memory
 SO_CFLAGS=-shared $(CFLAGS)
 L_CFLAGS=$(CFLAGS)
 LINK_FLAGS=
diff --git a/src/syscall-generic.h b/src/syscall-generic.h
index 24d7c7c..ffb35e0 100644
--- a/src/syscall-generic.h
+++ b/src/syscall-generic.h
@@ -1,10 +1,16 @@
 #include <errno.h>
 #include <unistd.h>
 #include <sys/syscall.h>
+#include <sanitizer/linux_syscall_hooks.h>
+
+#define PRE(name, ...) __sanitizer_syscall_pre_##name(__VA_ARGS__)
+#define POST(name, res, ...) __sanitizer_syscall_post_##name(res, __VA_ARGS__)
 
 #define _body_io_syscall(sname, args...) \
 { \
+	PRE(sname, ## args); \
 	int ret = syscall(__NR_##sname, ## args); \
+	POST(sname, ret, ## args); \
 	return ret < 0 ? -errno : ret; \
 }
 
diff --git a/src/syscall-x86_64.h b/src/syscall-x86_64.h
index 9361856..21beef2 100644
--- a/src/syscall-x86_64.h
+++ b/src/syscall-x86_64.h
@@ -1,3 +1,5 @@
+#include <sanitizer/linux_syscall_hooks.h>
+
 #define __NR_io_setup		206
 #define __NR_io_destroy		207
 #define __NR_io_getevents	208
@@ -7,13 +9,18 @@
 #define __syscall_clobber "r11","rcx","memory" 
 #define __syscall "syscall"
 
+#define PRE(name, ...) __sanitizer_syscall_pre_##name(__VA_ARGS__)
+#define POST(name, res, ...) __sanitizer_syscall_post_##name(res, __VA_ARGS__)
+
 #define io_syscall1(type,fname,sname,type1,arg1)			\
 type fname(type1 arg1)							\
 {									\
 long __res;								\
+PRE(sname, arg1); 							\
 __asm__ volatile (__syscall						\
 	: "=a" (__res)							\
 	: "0" (__NR_##sname),"D" ((long)(arg1)) : __syscall_clobber );	\
+POST(sname, __res, arg1);						\
 return __res;								\
 }
 
@@ -21,9 +28,11 @@ return __res;								\
 type fname(type1 arg1,type2 arg2)					\
 {									\
 long __res;								\
+PRE(sname, arg1, arg2);							\
 __asm__ volatile (__syscall						\
 	: "=a" (__res)							\
 	: "0" (__NR_##sname),"D" ((long)(arg1)),"S" ((long)(arg2)) : __syscall_clobber ); \
+POST(sname, __res, arg1, arg2);						\
 return __res;								\
 }
 
@@ -31,10 +40,12 @@ return __res;								\
 type fname(type1 arg1,type2 arg2,type3 arg3)				\
 {									\
 long __res;								\
+PRE(sname, arg1, arg2, arg3);						\
 __asm__ volatile (__syscall						\
 	: "=a" (__res)							\
 	: "0" (__NR_##sname),"D" ((long)(arg1)),"S" ((long)(arg2)),	\
 		  "d" ((long)(arg3)) : __syscall_clobber);		\
+POST(sname, __res, arg1, arg2, arg3);					\
 return __res;								\
 }
 
@@ -42,10 +53,12 @@ return __res;								\
 type fname (type1 arg1, type2 arg2, type3 arg3, type4 arg4)		\
 {									\
 long __res;								\
+PRE(sname, arg1, arg2, arg3, arg4);					\
 __asm__ volatile ("movq %5,%%r10 ;" __syscall				\
 	: "=a" (__res)							\
 	: "0" (__NR_##sname),"D" ((long)(arg1)),"S" ((long)(arg2)),	\
 	  "d" ((long)(arg3)),"g" ((long)(arg4)) : __syscall_clobber,"r10" ); \
+POST(sname, __res, arg1, arg2, arg3, arg4);				\
 return __res;								\
 } 
 
@@ -54,10 +67,12 @@ return __res;								\
 type fname (type1 arg1,type2 arg2,type3 arg3,type4 arg4,type5 arg5)	\
 {									\
 long __res;								\
+PRE(sname, arg1, arg2, arg3, arg4, arg5);				\
 __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " __syscall		\
 	: "=a" (__res)							\
 	: "0" (__NR_##sname),"D" ((long)(arg1)),"S" ((long)(arg2)),	\
 	  "d" ((long)(arg3)),"g" ((long)(arg4)),"g" ((long)(arg5)) :	\
 	__syscall_clobber,"r8","r10" );					\
+POST(sname, __res, arg1, arg2, arg3, arg4, arg5);			\
 return __res;								\
 }