Tue Nov 7 12:29:46 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>

	* elf/linux-compat.c: New file.
	* elf/Makefile (distribute): Add linux-compat.c.
	(generated): Add librtld.so.
	[$(config-os)=linux*] (extra-objs): Add linux-compat.so.
	[$(config-os)=linux*] (extra-objs): Add ld-linux.so.1.
	(librtld.so): New target.
	(ld.so, ld-linux.so.1): Make from librtld.so.

	* elf/rtld.c (dl_main): Instead of weak call to _dl_compat_init,
	call our own DT_INIT if we have one (and then clear it).
	(__dgettext): New weak function.

	* intl/localealias.c (read_alias_file): Avoid sprintf; use memcpy
	by hand instead.

	* sysdeps/generic/_strerror.c (_strerror_internal): Use _itoa
	instead of snprintf.

	* sysdeps/mach/_strerror.c (_strerror_internal): Don't write
	BUF[BUFLEN].

	* elf/rtld.c (rtld_map): New static variable.
	(_dl_start): Use a differently named local BOOTSTRAP_MAP for the
	bootstrapping.  Then copy data into `rtld_map'.
	(dl_main): Finish filling in rtld_map and link it into the chain,
	instead of allocating a new structure.
	(dl_main): Call _dl_compat_init if it is defined (use weak ref).

	* elf/dlsym.c: Fix last change: move REF out of `doit'.


	control.
	using it.

	and cwdir ports.
	functions.
	these.
	$(libdir)(rtld-installed-name).

	leading zeroes.

	in the rhs.
	pattern rule.


	never know.
	(fork): Use symbol_set_* macros for _hurd_fork_locks.
	* sysdeps/unix/sysv/sysv4/linux/i386/sysdep.S (__syscall_error):
 	instead of unix/sysv.

	-dynamic-linker.

	(__printf_fp): Last arg ARGS is now `const void **const';

	locale/C-ctype.c.
	* sysdeps/mach/hurd/sigsuspend.c: Likewise.
	* sysdeps/mach/hurd/mips/sigreturn.c: Likewise.
	alias gethostname.
	setitmr
	setpgrp
	(_S_msg_get_exec_flags, _S_msg_set_exec_flags,
	(abort_thread, abort_rpcs): Take same new arg and pass it through.

4 files changed, 120 insertions, 26 deletions

diff --git a/elf/Makefile b/elf/Makefile
index 21d2fc5..314289b 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -31,24 +31,42 @@ libdl-inhibit-o	= $(filter-out .so,$(object-suffixes)) # Build only shared.
 rtld-routines	:= rtld $(addprefix dl-,load lookup object reloc	\
 				        runtime sysdep error init fini)
 distribute	= $(rtld-routines:=.c) dynamic-link.h do-rel.h \
-		  soinit.c sofini.c ldd.sh.in
+		  soinit.c sofini.c ldd.sh.in linux-compat.c
 
 include ../Makeconfig
 
 ifeq (yes,$(build-shared))
 extra-objs	= $(rtld-routines:=.so) soinit.so sofini.so
+generated	= librtld.so
 install-others	= $(libdir)/$(rtld-installed-name)
 install-bin	= ldd
+
+ifneq (,$(filter linux%,$(config-os)))
+extra-objs	+= linux-compat.so
+install-lib	+= ld-linux.so.1
+endif
 endif
 
 include ../Rules
 
-$(objpfx)ld.so: $(rtld-routines:%=$(objpfx)%.so) \
-		$(patsubst %,$(common-objpfx)lib%_pic.a,\
-			   elf c $(LDLIBS-c.so:-l%=%))
-	$(LINK.o) -nostdlib -nostartfiles -shared -o $@ \
+
+# Link together the dynamic linker into a single relocatable object.
+# We use this to produce both the ABI-compliant and Linux-compatible
+# dynamic linker shared objects below.
+$(objpfx)librtld.so: $(rtld-routines:%=$(objpfx)%.so) \
+		     $(patsubst %,$(common-objpfx)lib%_pic.a,\
+				elf c $(LDLIBS-c.so:-l%=%))
+	$(LINK.o) -nostdlib -nostartfiles -r -o $@ \
 		  '-Wl,-(' $^ -lgcc '-Wl,-)'
 
+$(objpfx)ld.so $(objpfx)ld-linux.so.1: $(objpfx)librtld.so
+	$(LINK.o) -nostdlib -nostartfiles -shared -o $@ $^
+
+# The Linux-compatible dynamic linker shared object is just the same
+# with one object file of compatibility initialization code added.
+$(objpfx)ld-linux.so.1: $(objpfx)linux-compat.so
+
+
 $(objpfx)libdl.so: $(objpfx)libdl_pic.a $(common-objpfx)libc.so $(objpfx)ld.so
 	$(patsubst %/,cd %;,$(objpfx)) \
 	$(LINK.o) -shared -o $(@:$(objpfx)%=%) \
diff --git a/elf/dlsym.c b/elf/dlsym.c
index 8277ca3..0441e54 100644
--- a/elf/dlsym.c
+++ b/elf/dlsym.c
@@ -29,10 +29,10 @@ dlsym (void *handle, const char *name)
   struct link_map *map = handle;
   struct link_map *real_next;
   Elf32_Addr loadbase;
+  const Elf32_Sym *ref = NULL;
   int lose;
   void doit (void)
     {
-      const Elf32_Sym *ref = NULL;
       loadbase = _dl_lookup_symbol (name, &ref, map, map->l_name, 1);
     }
 
diff --git a/elf/linux-compat.c b/elf/linux-compat.c
new file mode 100644
index 0000000..ed1595e
--- /dev/null
+++ b/elf/linux-compat.c
@@ -0,0 +1,40 @@
+/* Initializer for Linux-compatible dynamic linker `/lib/ld-linux.so.1'.
+Copyright (C) 1995 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <link.h>
+#include <stdlib.h>
+
+/* This function will be the DT_INIT initializer for the ld-linux.so.1
+   shared object.  This is called from rtld.c before shlib initializers.
+
+   The old Linux ELF startup code expects the dynamic linker to magically
+   call atexit to arrange for shared object finalizers to run.  (The
+   ABI-compliant startup code does this itself.)  We build a compatible
+   version of the dynamic linker to install as /lib/ld-linux.so.1, the
+   name old Linux ELF binaries use.  */
+
+void
+_init (void)
+{
+  const Elf32_Sym *ref = NULL;
+  Elf32_Addr loadbase = _dl_lookup_symbol ("atexit", &ref, _dl_loaded,
+					   "<ld-linux.so.1 initialization>",
+					   1);
+  (*(__typeof (atexit) *) (loadbase + ref->st_value)) (&_dl_fini);
+}
diff --git a/elf/rtld.c b/elf/rtld.c
index 19f5439..9a822a8 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -50,22 +50,24 @@ static void dl_main (const Elf32_Phdr *phdr,
 		     Elf32_Word phent,
 		     Elf32_Addr *user_entry);
 
+static struct link_map rtld_map;
+
 Elf32_Addr
 _dl_start (void *arg)
 {
-  struct link_map rtld_map;
+  struct link_map bootstrap_map;
 
   /* Figure out the run-time load address of the dynamic linker itself.  */
-  rtld_map.l_addr = elf_machine_load_address ();
+  bootstrap_map.l_addr = elf_machine_load_address ();
 
   /* Read our own dynamic section and fill in the info array.
      Conveniently, the first element of the GOT contains the
      offset of _DYNAMIC relative to the run-time load address.  */
-  rtld_map.l_ld = (void *) rtld_map.l_addr + *elf_machine_got ();
-  elf_get_dynamic_info (rtld_map.l_ld, rtld_map.l_info);
+  bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + *elf_machine_got ();
+  elf_get_dynamic_info (bootstrap_map.l_ld, bootstrap_map.l_info);
 
 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
-  ELF_MACHINE_BEFORE_RTLD_RELOC (rtld_map.l_info);
+  ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info);
 #endif
 
   /* Relocate ourselves so we can do normal function calls and
@@ -77,8 +79,8 @@ _dl_start (void *arg)
      bootstrapping, so it must anti-perform each bootstrapping relocation
      before applying the final relocation when ld.so is linked in as
      normal a shared library.  */
-  rtld_map.l_type = lt_library;
-  ELF_DYNAMIC_RELOCATE (&rtld_map, 0, NULL);
+  bootstrap_map.l_type = lt_library;
+  ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, NULL);
 
 
   /* Now life is sane; we can call functions and access global data.
@@ -86,7 +88,12 @@ _dl_start (void *arg)
      the operating system's program loader where to find the program
      header table in core.  */
 
-  dl_r_debug.r_ldbase = rtld_map.l_addr; /* Record our load address.  */
+
+  /* Transfer data about ourselves to the permanent link_map structure.  */
+  rtld_map.l_addr = bootstrap_map.l_addr;
+  rtld_map.l_ld = bootstrap_map.l_ld;
+  memcpy (rtld_map.l_info, bootstrap_map.l_info, sizeof rtld_map.l_info);
+
 
   /* Call the OS-dependent function to set up life so we can do things like
      file access.  It will call `dl_main' (below) to do all the real work
@@ -122,9 +129,9 @@ dl_main (const Elf32_Phdr *phdr,
 	     itself!  This means someone ran ld.so as a command.  Well, that
 	     might be convenient to do sometimes.  We support it by
 	     interpreting the args like this:
-	     
+
 	     ld.so PROGRAM ARGS...
-	     
+
 	     The first argument is the name of a file containing an ELF
 	     executable we will load and run with the following arguments.
 	     To simplify life here, PROGRAM is searched for using the
@@ -228,8 +235,14 @@ of this helper program; chances are you did not intend to run this program.\n",
 	   will set up later to communicate with the debugger.  */
 	l->l_info[DT_DEBUG]->d_un.d_ptr = (Elf32_Addr) &dl_r_debug;
 
-      l = _dl_new_object ((char *) interpreter_name, interpreter_name,
-			  lt_interpreter);
+      /* Put the link_map for ourselves on the chain so it can be found by
+	 name.  */
+      rtld_map.l_name = (char *) rtld_map.l_libname = interpreter_name;
+      rtld_map.l_type = lt_interpreter;
+      while (l->l_next)
+	l = l->l_next;
+      l->l_next = &rtld_map;
+      rtld_map.l_prev = l;
 
       /* Now process all the DT_NEEDED entries and map in the objects.
 	 Each new link_map will go on the end of the chain, so we will
@@ -248,16 +261,13 @@ of this helper program; chances are you did not intend to run this program.\n",
 	  l->l_deps_loaded = 1;
 	}
 
-      l = _dl_loaded->l_next;
-      while (l->l_type != lt_interpreter)
-	l = l->l_next;
-      if (l->l_opencount == 0)
+      if (rtld_map.l_opencount == 0)
 	{
 	  /* No DT_NEEDED entry referred to the interpreter object itself.
 	     Remove it from the maps we will use for symbol resolution.  */
-	  l->l_prev->l_next = l->l_next;
-	  if (l->l_next)
-	    l->l_next->l_prev = l->l_prev;
+	  rtld_map.l_prev->l_next = rtld_map.l_next;
+	  if (rtld_map.l_next)
+	    rtld_map.l_next->l_prev = rtld_map.l_prev;
 	}
 
       lazy = !_dl_secure && *(getenv ("LD_BIND_NOW") ?: "") == '\0';
@@ -276,6 +286,7 @@ of this helper program; chances are you did not intend to run this program.\n",
 
       /* Tell the debugger where to find the map of loaded objects.  */
       dl_r_debug.r_version = 1	/* R_DEBUG_VERSION XXX */;
+      dl_r_debug.r_ldbase = rtld_map.l_addr; /* Record our load address.  */
       dl_r_debug.r_map = _dl_loaded;
       dl_r_debug.r_brk = (Elf32_Addr) &_dl_r_debug_state;
 
@@ -301,6 +312,19 @@ of this helper program; chances are you did not intend to run this program.\n",
 
 	  _exit (0);
 	}
+
+      if (rtld_map.l_info[DT_INIT])
+	{
+	  /* Call the initializer for the compatibility version of the
+	     dynamic linker.  There is no additional initialization
+	     required for the ABI-compliant dynamic linker.  */
+
+	  (*(void (*) (void)) (rtld_map.l_addr +
+			       rtld_map.l_info[DT_INIT]->d_un.d_ptr)) ();
+
+	  /* Clear the field so a future dlopen won't run it again.  */
+	  rtld_map.l_info[DT_INIT] = NULL;
+	}
     }
   const char *errstring;
   const char *errobj;
@@ -318,13 +342,25 @@ of this helper program; chances are you did not intend to run this program.\n",
      the DT_INIT functions and then *USER_ENTRY.  */
 }
 
-/* This function exists solely to have a breakpoint set on it by the 
+/* This function exists solely to have a breakpoint set on it by the
    debugger.  */
 void
 _dl_r_debug_state (void)
 {
 }
 
+/* Define our own stub for the localization function used by strerror.
+   English-only in the dynamic linker keeps it smaller.  */
+
+char *
+__dgettext (const char *domainname, const char *msgid)
+{
+  assert (domainname == _libc_intl_domainname);
+  return (char *) msgid;
+}
+weak_symbol (__dgettext)
+weak_alias (__dgettext, dgettext)
+
 #ifndef NDEBUG
 
 /* Define (weakly) our own assert failure function which doesn't use stdio.