[glibc/google/grte/v5-2.27/master] Extend elf/unload8 to test an additional load/unload pattern

[Fangrui Song <maskray@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=282bbfc364e9f0c5a0b006da377af6828e2048d8

commit 282bbfc364e9f0c5a0b006da377af6828e2048d8
Author: Stan Shebs <stanshebs@google.com>
Date:   Thu Jul 15 12:57:50 2021 -0700

    Extend elf/unload8 to test an additional load/unload pattern

Diff:
---
 elf/Makefile      |  2 +-
 elf/unload8.c     | 41 +++++++++++++++++++++++++++++++++++++++++
 elf/unload8mod1.c | 13 +++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/elf/Makefile b/elf/Makefile
index 827fe13178..43604e7d84 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -652,7 +652,7 @@ $(objpfx)unload6mod2.so: $(libdl)
 $(objpfx)unload6mod3.so: $(libdl)
 $(objpfx)unload7mod1.so: $(libdl)
 $(objpfx)unload7mod2.so: $(objpfx)unload7mod1.so
-$(objpfx)unload8mod1.so: $(objpfx)unload8mod2.so
+$(objpfx)unload8mod1.so: $(objpfx)unload8mod2.so $(libdl)
 $(objpfx)unload8mod2.so: $(objpfx)unload8mod3.so
 $(objpfx)unload8mod3.so: $(libdl)
 $(objpfx)tst-initordera2.so: $(objpfx)tst-initordera1.so
diff --git a/elf/unload8.c b/elf/unload8.c
index f984a38098..363af13d54 100644
--- a/elf/unload8.c
+++ b/elf/unload8.c
@@ -27,7 +27,48 @@ main (void)
     }
 
   mod1 ();
+
+  // Additional test to detect when the fastload hash table has bad pointers to
+  // names of unloaded libraries hanging around in it.
+
+  int (*mod1b) (void) = dlsym (h, "mod1b");
+  if (mod1b == NULL)
+    {
+      puts ("dlsym failed");
+      return 1;
+    }
+
+  mod1b ();
+
   dlclose (h);
 
+  void *h2x = dlopen ("$ORIGIN/unload8mod2.so", RTLD_LAZY);
+  if (h2x == NULL)
+    {
+      puts ("dlopen unload8mod2.so failed");
+      return 1;
+    }
+
+
+  void *h2xx = dlopen ("$ORIGIN/unload8mod1x.so", RTLD_LAZY);
+  if (h2xx == NULL)
+    {
+      puts ("dlopen unload8mod1x.so failed");
+      return 1;
+    }
+
+  dlclose (h);
+  dlclose (h2x);
+  dlclose (h2xx);
+
+  void *h3xx = dlopen ("$ORIGIN/unload8mod3.so", RTLD_LAZY);
+  if (h3xx == NULL)
+    {
+      puts ("dlopen unload8mod3.so failed");
+      return 1;
+    }
+
+  dlclose (h3xx);
+
   return 0;
 }
diff --git a/elf/unload8mod1.c b/elf/unload8mod1.c
index fe7e81c1c3..42a4298b6e 100644
--- a/elf/unload8mod1.c
+++ b/elf/unload8mod1.c
@@ -1,3 +1,5 @@
+#include <dlfcn.h>
+
 extern void mod2 (void);
 
 void
@@ -5,3 +7,14 @@ mod1 (void)
 {
   mod2 ();
 }
+
+void
+mod1b (void)
+{
+  void *h = dlopen ("$ORIGIN/unload8mod3.so", RTLD_LAZY);
+  if (h == NULL)
+    {
+      puts ("dlopen unload8mod3.so failed");
+      return 1;
+    }
+}