diff options
Diffstat (limited to 'sysdeps/stub')
| -rw-r--r-- | sysdeps/stub/dl-machine.h | 115 | ||||
| -rw-r--r-- | sysdeps/stub/dl-runtime.c | 64 |
2 files changed, 179 insertions, 0 deletions
diff --git a/sysdeps/stub/dl-machine.h b/sysdeps/stub/dl-machine.h new file mode 100644 index 0000000000..d9227233e4 --- /dev/null +++ b/sysdeps/stub/dl-machine.h @@ -0,0 +1,115 @@ +/* Machine-dependent ELF dynamic relocation inline functions. Stub 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. */ + +#define ELF_MACHINE_NAME "stub" + +#include <assert.h> +#include <string.h> +#include <link.h> + + +/* Return nonzero iff E_MACHINE is compatible with the running host. */ +static inline int +elf_machine_matches_host (Elf32_Half e_machine) +{ + switch (e_machine) + { + default: + return 0; + } +} + + +/* Return the run-time address of the _GLOBAL_OFFSET_TABLE_. */ +static inline Elf32_Addr * +elf_machine_got (void) +{ +#error "GOT not got" +} + + +/* Return the run-time load address of the shared object. */ +static inline Elf32_Addr +elf_machine_load_address (void) +{ +#error "Where am I?" +} + +/* This can modify DYNAMIC_INFO to avoid relocating code in + the functions above if they are doing bizarre magic. */ +#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */ + +/* Perform the relocation specified by RELOC and SYM (which is fully resolved). + LOADADDR is the load address of the object; INFO is an array indexed + by DT_* of the .dynamic section info. */ + +static inline void +elf_machine_rel (Elf32_Addr loadaddr, Elf32_Dyn *info[DT_NUM], + const Elf32_Rel *reloc, + Elf32_Addr sym_loadaddr, const Elf32_Sym *sym) +{ + Elf32_Addr *const reloc_addr = (Elf32_Addr *) reloc->r_offset; + const Elf32_Addr sym_value = sym_loadaddr + sym->st_value; + + switch (ELF32_R_TYPE (reloc->r_info)) + { + case R_MACHINE_COPY: + memcpy (reloc_addr, (void *) sym_value, sym->st_size); + break; + default: + assert (! "unexpected dynamic reloc type"); + break; + } +} + + +static inline void +elf_machine_rela (Elf32_Addr loadaddr, Elf32_Dyn *info[DT_NUM], + const Elf32_Rela *reloc, + Elf32_Addr sym_loadaddr, const Elf32_Sym *sym) +{ + _dl_signal_error (0, "Elf32_Rela relocation requested -- unused on " + ELF_MACHINE_NAME); +} + + +/* Set up the loaded object described by L so its unrelocated PLT + entries will jump to the on-demand fixup code in dl-runtime.c. */ + +static inline void +elf_machine_runtime_setup (struct link_map *l) +{ + extern void _dl_runtime_resolve (Elf32_Word); + /* The GOT entries for functions in the PLT have not yet been filled + in. Their initial contents will arrange when called to push an + offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1], + and then jump to _GLOBAL_OFFSET_TABLE[2]. */ + Elf32_Addr *got = (Elf32_Addr *) l->l_info[DT_PLTGOT]->d_un.d_ptr; + got[1] = (Elf32_Addr) l; /* Identify this shared object. */ + /* This function will get called to fix up the GOT entry indicated by + the offset on the stack, and then jump to the resolved address. */ + got[2] = (Elf32_Addr) &_dl_runtime_resolve; +} + + +/* Initial entry point code for the dynamic linker. + The C function `_dl_start' is the real entry point; + its return value is the user program's entry point. */ + +#define RTLD_START #error need some startup code diff --git a/sysdeps/stub/dl-runtime.c b/sysdeps/stub/dl-runtime.c new file mode 100644 index 0000000000..f660ef2197 --- /dev/null +++ b/sysdeps/stub/dl-runtime.c @@ -0,0 +1,64 @@ +/* On-demand PLT fixup for shared objects. Stub 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. */ + +#include <link.h> +#include "dynamic-link.h" + +/* This function is not called in the normal way. The PLT jumps here, not + using a call. */ +void +_dl_runtime_resolve () +{ + struct link_map *l = ???; + Elf32_Word reloc_offset = ???; + + 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); +} |