Another fix for TestBatchMode on linux

On locked down systems (such as our buildbot) one needs to do a special dance to allow attaching
to processes. This commit adds this code to the TestBatchMode inferior.

llvm-svn: 257165

lldb/packages/Python/lldbsuite/test/driver/batch_mode/main.c

@@ -2,9 +2,26 @@
 #include <string.h>
 #include <unistd.h>
 
+#if defined(__linux__)
+#include <sys/prctl.h>
+#endif
+
 int 
 main (int argc, char **argv)
 {
+#if defined(__linux__)
+        // Immediately enable any ptracer so that we can allow the stub attach
+        // operation to succeed.  Some Linux kernels are locked down so that
+        // only an ancestor process can be a ptracer of a process.  This disables that
+        // restriction.  Without it, attach-related stub tests will fail.
+#if defined(PR_SET_PTRACER) && defined(PR_SET_PTRACER_ANY)
+        // For now we execute on best effort basis.  If this fails for
+        // some reason, so be it.
+        const int prctl_result = prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0);
+        (void) prctl_result;
+#endif
+#endif
+
     int do_crash = 0;
     int do_wait = 0;