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authorRoland McGrath <roland@gnu.org>1995-05-02 06:35:55 +0000
committerRoland McGrath <roland@gnu.org>1995-05-02 06:35:55 +0000
commitd66e34cd423425c348bcc83df127dd19711b0b9a (patch)
tree97058e776d3b4fe06ef54bc4951596991652183f /elf/dl-reloc.c
parent08162fa888913a5153d2fcdc4e1a816b57b1fe56 (diff)
* sysdeps/mach/i386/sysdep.h (SNARF_ARGS, CALL_WITH_SP): Rewritten.
* sysdeps/i386/dl-machine.h: New file. * sysdeps/stub/dl-machine.h: New file. * sysdeps/i386/dl-runtime.c: New file. * sysdeps/stub/dl-runtime.c: New file. * sysdeps/i386/elf/start.S: New file. * sysdeps/generic/dl-sysdep.c: New file. * sysdeps/mach/hurd/dl-sysdep.c: New file.
Diffstat (limited to 'elf/dl-reloc.c')
-rw-r--r--elf/dl-reloc.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
new file mode 100644
index 0000000000..8efb3f04a6
--- /dev/null
+++ b/elf/dl-reloc.c
@@ -0,0 +1,115 @@
+/* Relocate a shared object and resolve its references to other loaded objects.
+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 <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include "dynamic-link.h"
+
+
+void
+_dl_relocate_object (struct link_map *l, int lazy)
+{
+ const size_t pagesize = getpagesize ();
+
+ if (l->l_relocated)
+ return;
+
+ if (l->l_info[DT_TEXTREL])
+ {
+ /* Bletch. We must make read-only segments writable
+ long enough to relocate them. */
+ const Elf32_Phdr *ph;
+ for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
+ if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
+ {
+ caddr_t mapstart = ((caddr_t) l->l_addr +
+ (ph->p_vaddr & ~(pagesize - 1)));
+ caddr_t mapend = ((caddr_t) l->l_addr +
+ ((ph->p_vaddr + ph->p_memsz + pagesize - 1)
+ & ~(pagesize - 1)));
+ if (mprotect (mapstart, mapend - mapstart,
+ PROT_READ|PROT_WRITE) < 0)
+ _dl_signal_error (errno,
+ "cannot make segment writable for relocation");
+ }
+ }
+
+ {
+ struct link_map *real_next, *scope;
+
+ const char *strtab
+ = ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
+
+
+ Elf32_Addr resolve (const Elf32_Sym **ref)
+ {
+ return _dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope);
+ }
+
+ 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;
+
+ elf_dynamic_relocate (l->l_info, l->l_addr, lazy, resolve);
+
+ /* Restore list frobnication done above for DT_SYMBOLIC. */
+ l->l_next = real_next;
+ l->l_prev->l_next = l;
+ }
+
+ if (l->l_info[DT_JMPREL] && ! lazy)
+ /* Set up the PLT so its unrelocated entries will
+ jump to _dl_runtime_resolve, which will relocate them. */
+ elf_machine_runtime_setup (l);
+
+ l->l_relocated = 1;
+
+ if (l->l_info[DT_TEXTREL])
+ {
+ /* Undo the protection change we made before relocating. */
+ const Elf32_Phdr *ph;
+ for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
+ if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
+ {
+ caddr_t mapstart = ((caddr_t) l->l_addr +
+ (ph->p_vaddr & ~(pagesize - 1)));
+ caddr_t mapend = ((caddr_t) l->l_addr +
+ ((ph->p_vaddr + ph->p_memsz + pagesize - 1)
+ & ~(pagesize - 1)));
+ int prot = 0;
+ if (ph->p_flags & PF_R)
+ prot |= PROT_READ;
+ if (ph->p_flags & PF_X)
+ prot |= PROT_EXEC;
+ if (mprotect (mapstart, mapend - mapstart, prot) < 0)
+ _dl_signal_error (errno,
+ "can't restore segment prot after reloc");
+ }
+ }
+
+}