1 files changed, 92 insertions, 0 deletions
diff --git a/sysdeps/i386/dl-runtime.c b/sysdeps/i386/dl-runtime.c
new file mode 100644
index 0000000..897524f
--- /dev/null
+++ b/sysdeps/i386/dl-runtime.c
@@ -0,0 +1,92 @@
+/* On-demand PLT fixup for shared objects.  i386 version.
+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.  */
+
+register void *sp asm ("%esp");
+
+#include <link.h>
+#include "dynamic-link.h"
+
+/* This function is not called in the normal way.  The PLT jumps here, not
+   using a call.  The stack looks like this:
+
+-->8(%esp)	address to return to the caller of the function in the PLT
+   4(%esp)	relocation offset for this PLT entry
+   0(%esp)	identifier for this shared object (struct link_map *)
+
+   The user expects the real function the PLT refers to to be entered
+   8(%esp) as the top of stack.  */
+
+void
+_dl_runtime_resolve (Elf32_Word reloc_offset)
+{
+  __label__ return_insn;
+  struct link_map *l = (void *) &(&reloc_offset)[-1];
+
+  const Elf32_Sym *const symtab
+    = (const Elf32_Sym *) l->l_info[DT_SYMTAB]->d_un.d_ptr;
+  const char *strtab
+    = ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
+
+  const Elf32_Rel *const reloc = (void *) (l->l_info[DT_JMPREL]->d_un.d_ptr
+					   + reloc_offset);
+
+  const Elf32_Sym *definer;
+  Elf32_Addr loadbase;
+  struct link_map *scope, *real_next;
+
+  /* Look up the symbol's run-time value.  */
+
+  real_next = l->l_next;
+  if (l->l_info[DT_SYMBOLIC])
+    {
+      l->l_prev->l_next = real_next;
+      l->l_next = _dl_loaded;
+      scope = l;
+    }
+  else
+    scope = _dl_loaded;
+  
+  definer = &symtab[ELF32_R_SYM (reloc->r_info)];
+  loadbase = _dl_lookup_symbol (strtab + definer->st_name, &definer, scope);
+  
+  /* Restore list frobnication done above for DT_SYMBOLIC.  */
+  l->l_next = real_next;
+  l->l_prev->l_next = l;
+
+  /* Apply the relocation with that value.  */
+  elf_machine_rel (l->l_addr, l->l_info, reloc, loadbase, definer);
+
+  /* The top of the stack is the word we set L from; but this location
+     holds the address we will return to.  Store there the address of a
+     "ret" instruction, which will pop the stack and run the code at the
+     address in the next stack word.  */
+  (&reloc_offset)[-1] = (Elf32_Word) &&return_insn;
+
+  /* The next stack word is our argument RELOC_OFFSET; but that "ret" will
+     pop and jump to this location, and the next stack word is the user's
+     return address.  So store here the resolved address of the function
+     referred to by this PLT entry; once "ret" pops this address, the
+     function in the shared object will run with the stack arranged just as
+     when the user entered the PLT.  */
+  (&reloc_offset)[0] = *(Elf32_Word *) reloc->r_offset;
+
+  return;
+
+ return_insn: asm volatile ("ret");
+}