Update.

* elf/elf.h: Add various DF_1_*, DTF_1_*, and DF_P1_* entries. * elf/dl-close.c (_dl_close): Don't close an object if it is marked with nodelete. * elf/dl-open.c (dl_open_worker): Pass RTLD_NOLOAD as new parameter to _dl_map_object. Return immediately if no object loaded. Set DF_1_NODELETE bit in l_flags_1 if RTLD_NODELETE was passed. * elf/dynamic-link.h (elf_get_dynamic_info): Copy DT_FLAGS_1 entry if it exists into l_flags_1 word. * elf/dl-load.c (_dl_map_object_from_fd): Take no parameter and use it to determine whether loading is wanted or not. (_dl_map_object): Likewise. Call _dl_map_object_from_fd with new parameter. * sysdeps/generic/ldsodefs.h: Update prototype. * elf/dl-deps.c: Add new parameter to _dl_map_object calls. * elf/rtld.c: Likewise. * elf/Makefile (tests): Add noload. Add rules to generate noload. * elf/noload.c: New file. * include/link.h (struct link_map): Add l_feature_1 and l_flags_1. * sysdeps/generic/bits/dlfcn.h: Define RTLD_NOLOAD and RTLD_NODELETE. * sysdeps/mips/bits/dlfcn.h: Likewise.
2024-09-19 16:10:01 +00:00 · 2000-07-20 22:53:54 +00:00 · 2000-07-20 22:53:54 +00:00 · bf8b3e74bf
commit bf8b3e74bf
parent 5e61ef8848
14 changed files with 179 additions and 27 deletions
--- a/21
+++ b/21
@ -1,5 +1,26 @@
 2000-07-20  Ulrich Drepper  <drepper@redhat.com>

+	* elf/elf.h: Add various DF_1_*, DTF_1_*, and DF_P1_* entries.
+	* elf/dl-close.c (_dl_close): Don't close an object if it is marked
+	with nodelete.
+	* elf/dl-open.c (dl_open_worker): Pass RTLD_NOLOAD as new parameter
+	to _dl_map_object.  Return immediately if no object loaded.
+	Set DF_1_NODELETE bit in l_flags_1 if RTLD_NODELETE was passed.
+	* elf/dynamic-link.h (elf_get_dynamic_info): Copy DT_FLAGS_1 entry
+	if it exists into l_flags_1 word.
+	* elf/dl-load.c (_dl_map_object_from_fd): Take no parameter and use
+	it to determine whether loading is wanted or not.
+	(_dl_map_object): Likewise.
+	Call _dl_map_object_from_fd with new parameter.
+	* sysdeps/generic/ldsodefs.h: Update prototype.
+	* elf/dl-deps.c: Add new parameter to _dl_map_object calls.
+	* elf/rtld.c: Likewise.
+	* elf/Makefile (tests): Add noload.  Add rules to generate noload.
+	* elf/noload.c: New file.
+	* include/link.h (struct link_map): Add l_feature_1 and l_flags_1.
+	* sysdeps/generic/bits/dlfcn.h: Define RTLD_NOLOAD and RTLD_NODELETE.
+	* sysdeps/mips/bits/dlfcn.h: Likewise.
+
 	* libio/Makefile (tests): Add tst_wprintf2.
 	(tst_wprintf2-ARGS): Define.
 	* libio/tst_wprintf2.c: New file.
--- a/bits/dlfcn.h
+++ b/bits/dlfcn.h
@ -22,20 +22,24 @@
 #endif

 /* The MODE argument to `dlopen' contains one of the following: */
-#define RTLD_LAZY	0x001	/* Lazy function call binding.  */
-#define RTLD_NOW	0x002	/* Immediate function call binding.  */
-#define	RTLD_BINDING_MASK 0x3	/* Mask of binding time value.  */
+#define RTLD_LAZY	0x00001	/* Lazy function call binding.  */
+#define RTLD_NOW	0x00002	/* Immediate function call binding.  */
+#define	RTLD_BINDING_MASK   0x3	/* Mask of binding time value.  */
+#define RTLD_NOLOAD	0x00004	/* Do not load the object.  */

 /* If the following bit is set in the MODE argument to `dlopen',
   the symbols of the loaded object and its dependencies are made
   visible as if the object were linked directly into the program.  */
-#define RTLD_GLOBAL	0x100
+#define RTLD_GLOBAL	0x00100

 /* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
   The implementation does this by default and so we can define the
   value to zero.  */
 #define RTLD_LOCAL	0

+/* Do not delete object when closed.  */
+#define RTLD_NODELETE	0x01000
+
 #ifdef __USE_GNU
 /* To support profiling of shared objects it is a good idea to call
   the function found using `dlsym' using the following macro since
--- a/elf/dl-close.c
+++ b/elf/dl-close.c
@ -48,6 +48,11 @@ _dl_close (void *_map)
  unsigned int nrellist;
  unsigned int i;

+  /* First see whether we can remove the object at all.  */
+  if (map->l_flags_1 & DF_1_NODELETE)
+    /* Nope.  Do nothing.  */
+    return;
+
  if (map->l_opencount == 0)
    _dl_signal_error (0, map->l_name, N_("shared object not open"));

@ -112,7 +117,8 @@ _dl_close (void *_map)
     points to, the 0th elt being MAP itself.  Decrement the reference
     counts on all the objects MAP depends on.  */
  for (i = 0; i < nsearchlist; ++i)
-    --list[i]->l_opencount;
+    if (! (list[i]->l_flags_1 & DF_1_NODELETE))
+      --list[i]->l_opencount;

  /* Check each element of the search list to see if all references to
     it are gone.  */
--- a/elf/dl-deps.c
+++ b/elf/dl-deps.c
@ -67,7 +67,7 @@ openaux (void *a)
  args->aux = _dl_map_object (args->map, args->name, 0,
 			      (args->map->l_type == lt_executable
 			       ? lt_library : args->map->l_type),
-			      args->trace_mode);
+			      args->trace_mode, 0);
 }


@ -232,7 +232,7 @@ _dl_map_object_deps (struct link_map *map,

 		dep = _dl_map_object (l, name, 0,
 				      l->l_type == lt_executable ? lt_library :
-				      l->l_type, trace_mode);
+				      l->l_type, trace_mode, 0);

 		/* Add it in any case to the duplicate list.  */
 		newp = alloca (sizeof (struct list));
@ -316,7 +316,7 @@ _dl_map_object_deps (struct link_map *map,
 		    args.aux = _dl_map_object (l, name, 0,
 					       (l->l_type == lt_executable
 						? lt_library : l->l_type),
-					       trace_mode);
+					       trace_mode, 0);
 		  }

 		/* The auxiliary object is actually available.
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@ -688,7 +688,7 @@ static
 #endif
 struct link_map *
 _dl_map_object_from_fd (const char *name, int fd, char *realname,
-			struct link_map *loader, int l_type)
+			struct link_map *loader, int l_type, int noload)
 {
  /* This is the expected ELF header.  */
 #define ELF32_CLASS ELFCLASS32
@ -752,6 +752,11 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname,
 	return l;
      }

+  if (noload)
+    /* We are not supposed to load the object unless it is already
+       loaded.  So return now.  */
+    return NULL;
+
  /* Print debugging message.  */
  if (__builtin_expect (_dl_debug_files, 0))
    _dl_debug_message (1, "file=", name, ";  generating link map\n", NULL);
@ -1301,7 +1306,7 @@ open_path (const char *name, size_t namelen, int preloaded,
 struct link_map *
 internal_function
 _dl_map_object (struct link_map *loader, const char *name, int preloaded,
-		int type, int trace_mode)
+		int type, int trace_mode, int noload)
 {
  int fd;
  char *realname;
@ -1501,5 +1506,5 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded,
 	_dl_signal_error (errno, name, N_("cannot open shared object file"));
    }

-  return _dl_map_object_from_fd (name, fd, realname, loader, type);
+  return _dl_map_object_from_fd (name, fd, realname, loader, type, noload);
 }
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@ -144,7 +144,17 @@ dl_open_worker (void *a)
    }

  /* Load the named object.  */
-  args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0);
+  args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0,
+				    mode & RTLD_NOLOAD);
+
+  /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
+     set and the object is not already loaded.  */
+  if (new == NULL)
+    {
+      assert (mode & RTLD_NOLOAD);
+      return;
+    }
+
  if (new->l_searchlist.r_list)
    /* It was already open.  */
    return;
@ -279,6 +289,11 @@ dl_open_worker (void *a)
      /* XXX Do we have to add something to r_dupsearchlist???  --drepper */
    }

+  /* Mark the object as not deletable if the RTLD_NODELETE flags was
+     passed.  */
+  if (__builtin_expect (mode & RTLD_NODELETE, 0))
+    new->l_flags_1 |= DF_1_NODELETE;
+
  if (_dl_sysdep_start == NULL)
    /* We must be the static _dl_open in libc.a.  A static program that
       has loaded a dynamic object now has competition.  */
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@ -114,6 +114,8 @@ elf_get_dynamic_info (struct link_map *l)
      if (flags & DF_BIND_NOW)
 	info[DT_BIND_NOW] = info[DT_FLAGS];
    }
+  if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
+    l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
  if (info[DT_RUNPATH] != NULL)
    /* If both RUNPATH and RPATH are given, the latter is ignored.  */
    info[DT_RPATH] = NULL;
--- a/elf/elf.h
+++ b/elf/elf.h
@ -622,7 +622,7 @@ typedef struct
 #define DT_PLTPADSZ	0x6ffffdf9
 #define DT_MOVEENT	0x6ffffdfa
 #define DT_MOVESZ	0x6ffffdfb
-#define DT_FEATURE_1	0x6ffffdfc
+#define DT_FEATURE_1	0x6ffffdfc	/* Feature selection (DTF_*).  */
 #define DT_POSFLAG_1	0x6ffffdfd	/* Flags for DT_* entries, effecting
 					   the following DT_* entry.  */
 #define DT_SYMINSZ	0x6ffffdfe	/* Size of syminfo table (in bytes) */
@ -678,6 +678,23 @@ typedef struct
 #define DF_1_LOADFLTR	0x00000010	/* Trigger filtee loading at runtime.*/
 #define DF_1_INITFIRST	0x00000020	/* Set RTLD_INITFIRST for this object*/
 #define DF_1_NOOPEN	0x00000040	/* Set RTLD_NOOPEN for this object.  */
+#define DF_1_ORIGIN	0x00000080	/* $ORIGIN must be handled.  */
+#define DF_1_DIRECT	0x00000100	/* Direct binding enabled.  */
+#define DF_1_TRANS	0x00000200
+#define DF_1_INTERPOSE	0x00000400	/* Object is used to interpose.  */
+#define DF_1_NODEFLIB	0x00000800	/* Ignore default lib search path.  */
+#define DF_1_NODUMP	0x00001000
+#define DF_1_CONFALT	0x00002000
+#define DF_1_ENDFILTEE	0x00004000
+
+/* Flags for the feature selection in DT_FEATURE_1.  */
+#define DTF_1_PARINIT	0x00000001
+#define DTF_1_CONFEXP	0x00000002
+
+/* Flags in the DT_POSFLAG_1 entry effecting only the next DT_* entry.  */
+#define DF_P1_LAZYLOAD	0x00000001	/* Lazyload following object.  */
+#define DF_P1_GROUPPERM	0x00000002	/* Symbols from next object are not
+					   generally available.  */

 /* Version definition sections.  */

--- a/elf/noload.c
+++ b/elf/noload.c
@ -0,0 +1,70 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int
+main (void)
+{
+  int result = 0;
+
+  /* First try to load an object which is a dependency.  This should
+     succeed.  */
+  if (dlopen ("testobj1.so", RTLD_LAZY | RTLD_NOLOAD) == NULL)
+    {
+      printf ("cannot open \"testobj1.so\": %s\n", dlerror ());
+      result = 1;
+    }
+  else
+    puts ("loading \"testobj1.so\" succeeded, OK");
+
+  /* Now try loading an object which is not already loaded.  */
+  if (dlopen ("testobj5.so", RTLD_LAZY | RTLD_NOLOAD) != NULL)
+    {
+      puts ("succeeded in loading \"testobj5.so\"");
+      result = 1;
+    }
+  else
+    {
+      /* Load the object and run the same test again.  */
+      void *p;
+
+      puts ("\"testobj5.so\" wasn't loaded and RTLD_NOLOAD prevented it, OK");
+
+      p = dlopen ("testobj5.so", RTLD_LAZY);
+
+      if (p == NULL)
+	{
+	  printf ("cannot open \"testobj5.so\" without RTLD_NOLOAD: %s\n",
+		  dlerror ());
+	  result = 1;
+	}
+      else
+	{
+	  puts ("loading \"testobj5.so\" succeeded, OK");
+
+	  if (dlopen ("testobj5.so", RTLD_LAZY | RTLD_NOLOAD) == NULL)
+	    {
+	      printf ("cannot open \"testobj5.so\": %s\n", dlerror ());
+	      result = 1;
+	    }
+	  else
+	    puts ("loading \"testobj5.so\" with RTLD_NOLOAD succeeded, OK");
+
+	  if (dlclose (p) != 0)
+	    {
+	      printf ("cannot close \"testobj5.so\": %s\n", dlerror ());
+	      result = 1;
+	    }
+	  else
+	    puts ("closing \"testobj5.so\" succeeded, OK");
+	}
+    }
+
+  return result;
+}
+
+
+int
+foo (int a)
+{
+  return 42 + a;
+}
--- a/elf/rtld.c
+++ b/elf/rtld.c
@ -313,7 +313,7 @@ static void
 map_doit (void *a)
 {
  struct map_args *args = (struct map_args *) a;
-  args->main_map = _dl_map_object (NULL, args->str, 0, lt_library, 0);
+  args->main_map = _dl_map_object (NULL, args->str, 0, lt_library, 0, 0);
 }

 static void
@ -514,7 +514,7 @@ of this helper program; chances are you did not intend to run this program.\n\
      else
 	{
 	  HP_TIMING_NOW (start);
-	  _dl_map_object (NULL, _dl_argv[0], 0, lt_library, 0);
+	  _dl_map_object (NULL, _dl_argv[0], 0, lt_library, 0, 0);
 	  HP_TIMING_NOW (stop);

 	  HP_TIMING_DIFF (load_time, start, stop);
@ -694,7 +694,7 @@ of this helper program; chances are you did not intend to run this program.\n\
 		|| strchr (p, '/') == NULL))
 	  {
 	    struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
-						       lt_library, 0);
+						       lt_library, 0, 0);
 	    if (new_map->l_opencount == 1)
 	      /* It is no duplicate.  */
 	      ++npreloads;
@ -762,7 +762,7 @@ of this helper program; chances are you did not intend to run this program.\n\
 	    if (p[0] != '\0')
 	      {
 		struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
-							   lt_library, 0);
+							   lt_library, 0, 0);
 		if (new_map->l_opencount == 1)
 		  /* It is no duplicate.  */
 		  ++npreloads;
@ -773,7 +773,7 @@ of this helper program; chances are you did not intend to run this program.\n\
 	{
 	  char *p = strndupa (problem, file_size - (problem - file));
 	  struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
-						     lt_library, 0);
+						     lt_library, 0, 0);
 	  if (new_map->l_opencount == 1)
 	    /* It is no duplicate.  */
 	    ++npreloads;
--- a/include/link.h
+++ b/include/link.h
@ -214,6 +214,10 @@ struct link_map
    unsigned int l_reldepsmax;
    unsigned int l_reldepsact;
    struct link_map **l_reldeps;
+
+    /* Various flag words.  */
+    ElfW(Word) l_feature_1;
+    ElfW(Word) l_flags_1;
  };

 #endif /* link.h */
--- a/sysdeps/generic/bits/dlfcn.h
+++ b/sysdeps/generic/bits/dlfcn.h
@ -22,20 +22,24 @@
 #endif

 /* The MODE argument to `dlopen' contains one of the following: */
-#define RTLD_LAZY	0x001	/* Lazy function call binding.  */
-#define RTLD_NOW	0x002	/* Immediate function call binding.  */
-#define	RTLD_BINDING_MASK 0x3	/* Mask of binding time value.  */
+#define RTLD_LAZY	0x00001	/* Lazy function call binding.  */
+#define RTLD_NOW	0x00002	/* Immediate function call binding.  */
+#define	RTLD_BINDING_MASK   0x3	/* Mask of binding time value.  */
+#define RTLD_NOLOAD	0x00004	/* Do not load the object.  */

 /* If the following bit is set in the MODE argument to `dlopen',
   the symbols of the loaded object and its dependencies are made
   visible as if the object were linked directly into the program.  */
-#define RTLD_GLOBAL	0x100
+#define RTLD_GLOBAL	0x00100

 /* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
   The implementation does this by default and so we can define the
   value to zero.  */
 #define RTLD_LOCAL	0

+/* Do not delete object when closed.  */
+#define RTLD_NODELETE	0x01000
+
 #ifdef __USE_GNU
 /* To support profiling of shared objects it is a good idea to call
   the function found using `dlsym' using the following macro since
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@ -271,7 +271,7 @@ extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
   value to allow additional security checks.  */
 extern struct link_map *_dl_map_object (struct link_map *loader,
 					const char *name, int preloaded,
-					int type, int trace_mode)
+					int type, int trace_mode, int noload)
     internal_function;

 /* Call _dl_map_object on the dependencies of MAP, and set up
--- a/sysdeps/mips/bits/dlfcn.h
+++ b/sysdeps/mips/bits/dlfcn.h
@ -22,20 +22,24 @@
 #endif

 /* The MODE argument to `dlopen' contains one of the following: */
-#define RTLD_LAZY	0x001	/* Lazy function call binding.  */
-#define RTLD_NOW	0x002	/* Immediate function call binding.  */
-#define	RTLD_BINDING_MASK 0x3	/* Mask of binding time value.  */
+#define RTLD_LAZY	0x0001	/* Lazy function call binding.  */
+#define RTLD_NOW	0x0002	/* Immediate function call binding.  */
+#define	RTLD_BINDING_MASK  0x3	/* Mask of binding time value.  */
+#define RTLD_NOLOAD	0x00008	/* Do not load the object.  */

 /* If the following bit is set in the MODE argument to `dlopen',
   the symbols of the loaded object and its dependencies are made
   visible as if the object were linked directly into the program.  */
-#define RTLD_GLOBAL	0x004
+#define RTLD_GLOBAL	0x0004

 /* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
   The implementation does this by default and so we can define the
   value to zero.  */
 #define RTLD_LOCAL      0

+/* Do not delete object when closed.  */
+#define RTLD_NODELETE	0x01000
+
 #ifdef __USE_GNU
 /* To support profiling of shared objects it is a good idea to call
   the function found using `dlsym' using the following macro since