elf: Run constructors on cyclic recursive dlopen (bug 31986)

This is conceptually similar to the reported bug, but does not
depend on auditing.  The fix is simple: just complete execution
of the constructors.  This exposed the fact that the link map
for statically linked executables does not have l_init_called
set, even though constructors have run.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

elf/Makefile

@@ -414,6 +414,7 @@ tests += \
   tst-dlmopen1 \
   tst-dlmopen3 \
   tst-dlmopen4 \
+  tst-dlopen-recurse \
   tst-dlopen-self \
   tst-dlopen-tlsmodid \
   tst-dlopen-tlsreinit1 \
@@ -865,6 +866,8 @@ modules-names += \
   tst-dlmopen-twice-mod1 \
   tst-dlmopen-twice-mod2 \
   tst-dlmopen1mod \
+  tst-dlopen-recursemod1 \
+  tst-dlopen-recursemod2 \
   tst-dlopen-tlsreinitmod1 \
   tst-dlopen-tlsreinitmod2 \
   tst-dlopen-tlsreinitmod3 \
@@ -3153,3 +3156,6 @@ $(objpfx)tst-dlopen-tlsreinit3.out: $(objpfx)tst-auditmod1.so
 tst-dlopen-tlsreinit3-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
 $(objpfx)tst-dlopen-tlsreinit4.out: $(objpfx)tst-auditmod1.so
 tst-dlopen-tlsreinit4-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
+
+$(objpfx)tst-dlopen-recurse.out: $(objpfx)tst-dlopen-recursemod1.so
+$(objpfx)tst-dlopen-recursemod1.so: $(objpfx)tst-dlopen-recursemod2.so

elf/dl-open.c

@@ -590,6 +590,14 @@ dl_open_worker_begin (void *a)
         = _dl_debug_update (args->nsid)->r_state;
       assert (r_state == RT_CONSISTENT);
 
+      /* Do not return without calling the (supposedly new) map's
+	 constructor.  This case occurs if a dependency of a directly
+	 opened map has a constructor that calls dlopen again on the
+	 initially opened map.  The new map is initialized last, so
+	 checking only it is enough.  */
+      if (!new->l_init_called)
+	_dl_catch_exception (NULL, call_dl_init, args);
+
       return;
     }
 

elf/dl-support.c

@@ -99,6 +99,7 @@ static struct link_map _dl_main_map =
     .l_used = 1,
     .l_tls_offset = NO_TLS_OFFSET,
     .l_serial = 1,
+    .l_init_called = 1,
   };
 
 /* Namespace information.  */

elf/tst-dlopen-recurse.c

@@ -0,0 +1,34 @@
+/* Test that recursive dlopen runs constructors before return (bug 31986).
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <support/check.h>
+#include <support/xdlfcn.h>
+
+static int
+do_test (void)
+{
+  void *handle = xdlopen ("tst-dlopen-recursemod1.so", RTLD_NOW);
+  int *status = dlsym (handle, "recursemod1_status");
+  printf ("info: recursemod1_status == %d (from main)\n", *status);
+  TEST_COMPARE (*status, 2);
+  xdlclose (handle);
+  return 0;
+}
+
+#include <support/test-driver.c>

elf/tst-dlopen-recursemod1.c

@@ -0,0 +1,50 @@
+/* Directly opened test module that gets recursively opened again.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <support/xdlfcn.h>
+
+int recursemod1_status;
+
+/* Force linking against st-dlopen-recursemod2.so.  Also allows
+   checking for relocation.  */
+extern int recursemod2_status;
+int *force_recursemod2_reference = &recursemod2_status;
+
+static void __attribute__ ((constructor))
+init (void)
+{
+  ++recursemod1_status;
+  printf ("info: tst-dlopen-recursemod1.so constructor called (status %d)\n",
+          recursemod1_status);
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+  /* The recursemod1_status variable was incremented in the
+     tst-dlopen-recursemod2.so constructor.  */
+  printf ("info: tst-dlopen-recursemod1.so destructor called (status %d)\n",
+          recursemod1_status);
+  if (recursemod1_status != 2)
+    {
+      puts ("error: recursemod1_status == 2 expected");
+      exit (1);
+    }
+}

elf/tst-dlopen-recursemod2.c

@@ -0,0 +1,66 @@
+/* Indirectly opened module that recursively opens the directly opened module.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int recursemod2_status;
+
+static void __attribute__ ((constructor))
+init (void)
+{
+  ++recursemod2_status;
+  printf ("info: tst-dlopen-recursemod2.so constructor called (status %d)\n",
+          recursemod2_status);
+  void *handle = dlopen ("tst-dlopen-recursemod1.so", RTLD_NOW);
+  if (handle == NULL)
+    {
+      printf ("error: dlopen: %s\n", dlerror ());
+      exit (1);
+    }
+  int *status = dlsym (handle, "recursemod1_status");
+  if (status == NULL)
+    {
+      printf ("error: dlsym: %s\n", dlerror ());
+      exit (1);
+    }
+  printf ("info: recursemod1_status == %d\n", *status);
+  if (*status != 1)
+    {
+      puts ("error: recursemod1_status == 1 expected");
+      exit (1);
+    }
+  ++*status;
+  printf ("info: recursemod1_status == %d\n", *status);
+
+  int **mod2_status = dlsym (handle, "force_recursemod2_reference");
+  if (mod2_status == NULL || *mod2_status != &recursemod2_status)
+    {
+      puts ("error: invalid recursemod2_status address in"
+            " tst-dlopen-recursemod1.so");
+      exit (1);
+    }
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+  printf  ("info: tst-dlopen-recursemod2.so destructor called (status %d)\n",
+           recursemod2_status);
+}