[glibc] Fix WAIT_FOR_DEBUGGER for container tests.

[Stefan Liebler <stli@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4a829d70ab3bc9e69f3d186471d043e07e0d78d8

commit 4a829d70ab3bc9e69f3d186471d043e07e0d78d8
Author: Stefan Liebler <stli@linux.ibm.com>
Date:   Thu Sep 28 12:50:40 2023 +0200

    Fix WAIT_FOR_DEBUGGER for container tests.
    
    For container tests, gdb needs to set the sysroot to the corresponding
    testroot.root directory.  The assumption was that PIDs < 3 means that
    we are running within a container.
    
    Starting with commit 2fe64148a81f0d78050c302f34a6853d21f7cae4
    "Allow for unpriviledged nested containers", the default is to use
    the PID namespace of the parent.  Thus support_test_main.c does not
    recognize our container anymore.
    
    This patch now assumes that we are running inside a container if
    test-container.c has set PID_OUTSIDE_CONTAINER and always uses this
    PID independent of having a new PID namespace or not.
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 support/support_test_main.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/support/support_test_main.c b/support/support_test_main.c
index c20c19e774..f19fce5644 100644
--- a/support/support_test_main.c
+++ b/support/support_test_main.c
@@ -195,16 +195,14 @@ run_test_function (int argc, char **argv, const struct test_config *config)
       char *gdb_script_name;
       int inside_container = 0;
 
-      mypid = getpid();
-      if (mypid < 3)
+      const char *outside_pid = getenv("PID_OUTSIDE_CONTAINER");
+      if (outside_pid)
 	{
-	  const char *outside_pid = getenv("PID_OUTSIDE_CONTAINER");
-	  if (outside_pid)
-	    {
-	      mypid = atoi (outside_pid);
-	      inside_container = 1;
-	    }
+	  mypid = atoi (outside_pid);
+	  inside_container = 1;
 	}
+      else
+	mypid = getpid();
 
       gdb_script_name = (char *) xmalloc (strlen (argv[0]) + strlen (".gdb") + 1);
       sprintf (gdb_script_name, "%s.gdb", argv[0]);