[glibc] dlfcn: Eliminate GLIBC_PRIVATE dependency from tststatic2

[glibc] dlfcn: Eliminate GLIBC_PRIVATE dependency from tststatic2

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9c76debc983e1a16e2e723b36526826713a671af

commit 9c76debc983e1a16e2e723b36526826713a671af
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Jun 3 08:26:04 2021 +0200

    dlfcn: Eliminate GLIBC_PRIVATE dependency from tststatic2
    
    The test appears to use _dlfcn_hook@@GLIBC_PRIVATE as a way to
    test dlvsym without having to know the appropriate symbol version.
    With <first-versions.h>, we can use a public symbol and the symbol
    version at which it was defined first.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 dlfcn/modstatic2.c | 10 +++++++++-
 dlfcn/tststatic2.c | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/dlfcn/modstatic2.c b/dlfcn/modstatic2.c
index 9b5aae8b9f..02d561a7b0 100644
--- a/dlfcn/modstatic2.c
+++ b/dlfcn/modstatic2.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <gnu/lib-names.h>
+#include <first-versions.h>
 
 int test (FILE *out, int a);
 
@@ -117,11 +118,18 @@ test (FILE *out, int a)
       exit (1);
     }
 
-  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
+  /* _exit is very unlikely to receive a second symbol version.  */
+  void *exit_ptr = dlvsym (handle2, "_exit", FIRST_VERSION_libc__exit_STRING);
+  if (exit_ptr == NULL)
     {
       fprintf (out, "dlvsym: %s\n", dlerror ());
       exit (1);
     }
+  if (exit_ptr != dlsym (handle2, "_exit"))
+    {
+      fprintf (out, "dlvsym for _exit does not match dlsym\n");
+      exit (1);
+    }
 
   void *(*dlsymfn) (void *, const char *);
   dlsymfn = dlsym (handle2, "dlsym");
diff --git a/dlfcn/tststatic2.c b/dlfcn/tststatic2.c
index f8cd5a964b..5d8a7831b2 100644
--- a/dlfcn/tststatic2.c
+++ b/dlfcn/tststatic2.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <gnu/lib-names.h>
+#include <first-versions.h>
 
 static int
 do_test (void)
@@ -115,11 +116,18 @@ do_test (void)
       exit (1);
     }
 
-  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
+  /* _exit is very unlikely to receive a second symbol version.  */
+  void *exit_ptr = dlvsym (handle2, "_exit", FIRST_VERSION_libc__exit_STRING);
+  if (exit_ptr == NULL)
     {
       printf ("dlvsym: %s\n", dlerror ());
       exit (1);
     }
+  if (exit_ptr != dlsym (handle2, "_exit"))
+    {
+      printf ("dlvsym for _exit does not match dlsym\n");
+      exit (1);
+    }
 
   void *(*dlsymfn) (void *, const char *);
   dlsymfn = dlsym (handle2, "dlsym");