libsandbox: add x32 ABI supportv2.6

We can trace x32 when the host is x86_64 or x32, but x32 cannot trace
x86_64 due to limitations in the kernel interface -- all pointers get
truncated to 32bits.  We'll have to add external ptrace helpers in the
future to make this work, but for now, we'll just let x86_64 code run
unchecked :(.

URL: https://bugs.gentoo.org/394179
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/libsandbox/trace.c b/libsandbox/trace.c
index f2071e0..ea769fd 100644
--- a/libsandbox/trace.c
+++ b/libsandbox/trace.c
@@ -11,6 +11,7 @@
 
 static long _do_ptrace(enum __ptrace_request request, const char *srequest, void *addr, void *data);
 #define do_ptrace(request, addr, data) _do_ptrace(request, #request, addr, data)
+#define _trace_possible(data) true
 
 #ifdef DEBUG
 # define SBDEBUG 1
@@ -485,6 +486,16 @@ void trace_main(const char *filename, char *const argv[])
 
 #else
 
+#undef _trace_possible
+#define _trace_possible(data) false
+
+void trace_main(const char *filename, char *const argv[])
+{
+	/* trace_possible() triggers a warning for us */
+}
+
+#endif
+
 static char *flatten_args(char *const argv[])
 {
 	char *ret;
@@ -512,11 +523,13 @@ static char *flatten_args(char *const argv[])
 	return ret;
 }
 
-void trace_main(const char *filename, char *const argv[])
+bool trace_possible(const char *filename, char *const argv[], const void *data)
 {
+	if (_trace_possible(data))
+		return true;
+
 	char *args = flatten_args(argv);
-	sb_eqawarn("Static ELF: %s: %s\n", filename, args);
+	sb_eqawarn("Unable to trace static ELF: %s: %s\n", filename, args);
 	free(args);
+	return false;
 }
-
-#endif