Fix intercept of SYS_open on platforms that only have SYS_openat (e.g. arm64)

4 files changed, 17 insertions, 8 deletions

diff --git a/infrastructure/m4/boxbackup_tests.m4 b/infrastructure/m4/boxbackup_tests.m4
index 849ffd7a..7410159a 100644
--- a/infrastructure/m4/boxbackup_tests.m4
+++ b/infrastructure/m4/boxbackup_tests.m4
@@ -224,6 +224,7 @@ AC_CHECK_DECLS([INFTIM],,, [[#include <poll.h>]])
 AC_CHECK_DECLS([SO_PEERCRED],,, [[#include <sys/socket.h>]])
 AC_CHECK_DECLS([SOL_TCP],,, [[#include <netinet/tcp.h>]])
 AC_CHECK_DECLS([TCP_INFO],,, [[#include <netinet/tcp.h>]])
+AC_CHECK_DECLS([SYS_open, SYS_openat],,, [[#include <sys/syscall.h>]])
 
 if test -n "$have_sys_socket_h"; then
   AC_CHECK_DECLS([SO_SNDBUF],,, [[#include <sys/socket.h>]])
diff --git a/lib/intercept/intercept.cpp b/lib/intercept/intercept.cpp
index ac8c4431..72bd8d4e 100644
--- a/lib/intercept/intercept.cpp
+++ b/lib/intercept/intercept.cpp
@@ -242,6 +242,10 @@ extern "C" int
 	open(const char *path, int flags, ...)
 #endif // DEFINE_ONLY_OPEN64
 {
+	// Some newer architectures don't have an open() syscall, but use openat() instead.
+	// In these cases we will need to call sys_openat() instead of sys_open().
+	// https://chromium.googlesource.com/linux-syscall-support/
+
 	if(intercept_count > 0)
 	{
 		if(intercept_filename != NULL &&
@@ -264,6 +268,8 @@ extern "C" int
 
 #ifdef PLATFORM_NO_SYSCALL
 	int r = TEST_open(path, flags, mode);
+#elif HAVE_DECL_SYS_OPENAT && !HAVE_DECL_SYS_OPEN
+	int r = syscall(SYS_openat, AT_FDCWD, path, flags, mode);
 #else
 	int r = syscall(SYS_open, path, flags, mode);
 #endif
diff --git a/lib/intercept/intercept.h b/lib/intercept/intercept.h
index c0d61638..4de5f9f2 100644
--- a/lib/intercept/intercept.h
+++ b/lib/intercept/intercept.h
@@ -62,5 +62,14 @@ void intercept_setup_stat_post_hook (lstat_post_hook_t hookfn);
 
 void intercept_clear_setup();
 
+// Some newer architectures don't have an open() syscall, but use openat() instead.
+// In these cases we define SYS_open (which is otherwise undefined) to equal SYS_openat
+// (which is defined) so that everywhere else we can call intercept_setup_error(SYS_open)
+// without caring about the difference.
+// https://chromium.googlesource.com/linux-syscall-support/
+#if !HAVE_DECL_SYS_OPEN && HAVE_DECL_SYS_OPENAT
+#	define SYS_open SYS_openat
+#endif
+
 #endif // !PLATFORM_CLIB_FNS_INTERCEPTION_IMPOSSIBLE
 #endif // !INTERCEPT_H
diff --git a/test/raidfile/testraidfile.cpp b/test/raidfile/testraidfile.cpp
index c8150387..d771f23d 100644
--- a/test/raidfile/testraidfile.cpp
+++ b/test/raidfile/testraidfile.cpp
@@ -25,6 +25,7 @@
 #include "RaidFileException.h"
 #include "RaidFileRead.h"
 #include "Guards.h"
+#include "intercept.h"
 
 #include "MemLeakFindOn.h"
 
@@ -37,14 +38,6 @@
 	#define	TRF_CAN_INTERCEPT
 #endif
 
-
-#ifdef TRF_CAN_INTERCEPT
-// function in intercept.cpp for setting up errors
-void intercept_setup_error(const char *filename, unsigned int errorafter, int errortoreturn, int syscalltoerror);
-bool intercept_triggered();
-void intercept_clear_setup();
-#endif
-
 // Nice random data for testing written files
 class R250 {
 public: