libdl: dlopen() mustn't forget RTLD_NODELETE flag

If RTLD_NODELETE is passed to dlopen() rather than set on shared
library itself, flag propagation to rtld_flags is missed.

Test-case taken from glibc.

Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>
Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>

ldso/libdl/libdl.c

@@ -394,7 +394,7 @@ static void *do_dlopen(const char *libname, int flag, ElfW(Addr) from)
 	dyn_chain = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
 	memset(dyn_chain, 0, sizeof(struct dyn_elf));
 	dyn_chain->dyn = tpnt;
-	tpnt->rtld_flags |= (flag & RTLD_GLOBAL);
+	tpnt->rtld_flags |= (flag & (RTLD_GLOBAL|RTLD_NODELETE));
 
 	dyn_chain->next_handle = _dl_handles;
 	_dl_handles = dyn_ptr = dyn_chain;
@@ -407,7 +407,7 @@ static void *do_dlopen(const char *libname, int flag, ElfW(Addr) from)
 				dyn_chain->init_fini.init_fini = handle->init_fini.init_fini;
 				dyn_chain->init_fini.nlist = handle->init_fini.nlist;
 				for (i = 0; i < dyn_chain->init_fini.nlist; i++)
-					dyn_chain->init_fini.init_fini[i]->rtld_flags |= (flag & RTLD_GLOBAL);
+					dyn_chain->init_fini.init_fini[i]->rtld_flags |= (flag & (RTLD_GLOBAL|RTLD_NODELETE));
 				dyn_chain->next = handle->next;
 				break;
 			}
@@ -439,7 +439,7 @@ static void *do_dlopen(const char *libname, int flag, ElfW(Addr) from)
 				if (!tpnt1)
 					goto oops;
 
-				tpnt1->rtld_flags |= (flag & RTLD_GLOBAL);
+				tpnt1->rtld_flags |= (flag & (RTLD_GLOBAL|RTLD_NODELETE));
 
 				/* This list is for dlsym() and relocation */
 				dyn_ptr->next = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));

test/dlopen/Makefile.in

@@ -5,7 +5,7 @@
 export UCLIBC_ONLY := 1
 
 TESTS := dltest dltest2 dlstatic test1 test2 test3 dlundef dlafk dladdr \
-	testscope
+	testscope nodelete
 
 ifneq ($(HAVE_SHARED),y)
 TESTS_DISABLED := test3
@@ -63,3 +63,10 @@ LDFLAGS_libtest3.so := -lpthread -Wl,-rpath,.
 LDFLAGS_libC.so := -ldl
 LDFLAGS_libB.so := ./libC.so -Wl,-rpath,.
 LDFLAGS_libA.so := ./libB.so -Wl,-rpath,.
+
+nodelete: nodelmod1.so nodelmod2.so nodelmod3.so
+nodelmod3.so: nodelmod4.so
+LDFLAGS_nodelete := -rdynamic -ldl
+LDFLAGS_nodelmod1.so := -Wl,-z,nodelete
+LDFLAGS_nodelmod3.so := ./nodelmod4.so
+LDFLAGS_nodelmod4.so := -Wl,-z,nodelete

test/dlopen/nodelete.c

@@ -0,0 +1,205 @@
+#include <dlfcn.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+
+static sigjmp_buf jmpbuf;
+
+
+int fini_ran;
+
+
+static void
+__attribute__ ((noreturn))
+handler (int sig)
+{
+  siglongjmp (jmpbuf, 1);
+}
+
+
+#define TEST_FUNCTION do_test ()
+static int
+do_test (void)
+{
+  /* We are testing the two possibilities to mark an object as not deletable:
+     - marked on the linker commandline with `-z nodelete'
+     - with the RTLD_NODELETE flag at dlopen()-time.
+
+     The test we are performing should be safe.  We are loading the objects,
+     get the address of variables in the respective object, unload the object
+     and then try to read the variable.  If the object is unloaded this
+     should lead to an segmentation fault.  */
+  void *p;
+  struct sigaction sa;
+
+  sa.sa_handler = handler;
+  sigfillset (&sa.sa_mask);
+  sa.sa_flags = SA_RESTART;
+
+  if (sigaction (SIGSEGV, &sa, NULL) == -1)
+    puts ("cannot install signal handler: %m");
+
+  p = dlopen ("nodelmod1.so", RTLD_LAZY);
+  if (p == NULL)
+    {
+      printf ("failed to load \"nodelmod1.so\": %s\n", dlerror ());
+      exit (1);
+    }
+  else
+    {
+      int *varp;
+
+      varp = dlsym (p, "var1");
+      if (varp == NULL)
+	{
+	  puts ("failed to get address of \"var1\" in \"nodelmod1.so\"");
+	  exit (1);
+	}
+      else
+	{
+	  *varp = 20000720;
+
+	  /* Now close the object.  */
+	  fini_ran = 0;
+	  if (dlclose (p) != 0)
+	    {
+	      puts ("failed to close \"nodelmod1.so\"");
+	      exit (1);
+	    }
+	  else if (! sigsetjmp (jmpbuf, 1))
+	    {
+	      /* Access the variable again.  */
+	      if (*varp != 20000720)
+		{
+		  puts ("\"var1\" value not correct");
+		  exit (1);
+		}
+	      else if (fini_ran != 0)
+		{
+		  puts ("destructor of \"nodelmod1.so\" ran");
+		  exit (1);
+		}
+	      else
+		puts ("-z nodelete test succeeded");
+	    }
+	  else
+	    {
+	      /* We caught an segmentation fault.  */
+	      puts ("\"nodelmod1.so\" got deleted!");
+	      exit (1);
+	    }
+	}
+    }
+
+  p = dlopen ("nodelmod2.so", RTLD_LAZY | RTLD_NODELETE);
+  if (p == NULL)
+    {
+      printf ("failed to load \"nodelmod2.so\": %s\n", dlerror ());
+      exit (1);
+    }
+  else
+    {
+      int *varp;
+
+      varp = dlsym (p, "var2");
+      if (varp == NULL)
+	{
+	  puts ("failed to get address of \"var2\" in \"nodelmod2.so\"");
+	  exit (1);
+	}
+      else
+	{
+	  *varp = 42;
+
+	  /* Now close the object.  */
+	  fini_ran = 0;
+	  if (dlclose (p) != 0)
+	    {
+	      puts ("failed to close \"nodelmod2.so\"");
+	      exit (1);
+	    }
+	  else if (! sigsetjmp (jmpbuf, 1))
+	    {
+	      /* Access the variable again.  */
+	      if (*varp != 42)
+		{
+		  puts ("\"var2\" value not correct");
+		  exit (1);
+		}
+	      else if (fini_ran != 0)
+		{
+		  puts ("destructor of \"nodelmod2.so\" ran");
+		  exit (1);
+		}
+	      else
+		puts ("RTLD_NODELETE test succeeded");
+	    }
+	  else
+	    {
+	      /* We caught an segmentation fault.  */
+	      puts ("\"nodelmod2.so\" got deleted!");
+	      exit (1);
+	    }
+	}
+    }
+
+  p = dlopen ("nodelmod3.so", RTLD_LAZY);
+  if (p == NULL)
+    {
+      printf ("failed to load \"nodelmod3.so\": %s\n", dlerror ());
+      exit (1);
+    }
+  else
+    {
+      int *(*fctp) (void);
+
+      fctp = dlsym (p, "addr");
+      if (fctp == NULL)
+	{
+	  puts ("failed to get address of \"addr\" in \"nodelmod3.so\"");
+	  exit (1);
+	}
+      else
+	{
+	  int *varp = fctp ();
+
+	  *varp = -1;
+
+	  /* Now close the object.  */
+	  fini_ran = 0;
+	  if (dlclose (p) != 0)
+	    {
+	      puts ("failed to close \"nodelmod3.so\"");
+	      exit (1);
+	    }
+	  else if (! sigsetjmp (jmpbuf, 1))
+	    {
+	      /* Access the variable again.  */
+	      if (*varp != -1)
+		{
+		  puts ("\"var_in_mod4\" value not correct");
+		  exit (1);
+		}
+	      else if (fini_ran != 0)
+		{
+		  puts ("destructor of \"nodelmod4.so\" ran");
+		  exit (1);
+		}
+	      else
+		puts ("-z nodelete in dependency succeeded");
+	    }
+	  else
+	    {
+	      /* We caught an segmentation fault.  */
+	      puts ("\"nodelmod4.so\" got deleted!");
+	      exit (1);
+	    }
+	}
+    }
+
+  return 0;
+}
+
+#include "../test-skeleton.c"

test/dlopen/nodelmod1.c

@@ -0,0 +1,10 @@
+extern int fini_ran;
+
+int var1 = 42;
+
+static void
+__attribute__ ((__destructor__))
+destr (void)
+{
+  fini_ran = 1;
+}

test/dlopen/nodelmod2.c

@@ -0,0 +1,10 @@
+extern int fini_ran;
+
+int var2 = 100;
+
+static void
+__attribute__ ((__destructor__))
+destr (void)
+{
+  fini_ran = 1;
+}

test/dlopen/nodelmod3.c

@@ -0,0 +1,8 @@
+extern int var_in_mod4;
+extern int *addr (void);
+
+int *
+addr (void)
+{
+  return &var_in_mod4;
+}

test/dlopen/nodelmod4.c

@@ -0,0 +1,10 @@
+extern int fini_ran;
+
+int var_in_mod4 = 99;
+
+static void
+__attribute__ ((__destructor__))
+destr (void)
+{
+  fini_ran = 1;
+}