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authorlinted <linted@users.noreply.github.com>2022-08-20 16:41:38 -0400
committerWaldemar Brodkorb <wbx@openadk.org>2022-09-07 08:32:47 +0200
commit365da5ab379a3e38e196cad370695c4b300cfe51 (patch)
treeaa4eeb3a03c03dcd11570247b328086f2c9208ac /libc/misc/internals/reloc_static_pie.c
parentd46709504efa46e5b9b52739a48ab61b39fd4971 (diff)
Added support for creation of Static Position-Independent Executables (PIE) on mips
Updated config to allow compilation of rcrt1.o for mips and modified it's crt1.S to perform relocates in __start. The mips architecture performs relocations differently then most other architectures. reloc_static_pie was rewritten, taking code from dl-startup.c, in order to perfrom the additional relocations. Modifications were made to mips' dl-startup.h to allow for the use of contained macros without including _start definition. Signed-off-by: linted <linted@users.noreply.github.com>
Diffstat (limited to 'libc/misc/internals/reloc_static_pie.c')
-rw-r--r--libc/misc/internals/reloc_static_pie.c93
1 files changed, 78 insertions, 15 deletions
diff --git a/libc/misc/internals/reloc_static_pie.c b/libc/misc/internals/reloc_static_pie.c
index 578202d23..c0027de6f 100644
--- a/libc/misc/internals/reloc_static_pie.c
+++ b/libc/misc/internals/reloc_static_pie.c
@@ -15,33 +15,96 @@
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-
+#define IS_IN_rtld // force inline function calls
#include <link.h>
#include <elf.h>
#include <dl-elf.h>
+#include <ldso.h>
+#ifdef __mips__
+#include <dl-startup.h>
+#endif
+
ElfW(Addr) _dl_load_base = NULL;
void
reloc_static_pie (ElfW(Addr) load_addr);
void
-reloc_static_pie (ElfW(Addr) load_addr)
+reloc_static_pie(ElfW(Addr) load_addr)
{
- ElfW(Word) relative_count = 0;
- ElfW(Addr) rel_addr = 0;
- ElfW(Dyn) * dyn_addr = NULL;
- unsigned long dynamic_info[DYNAMIC_SIZE] = {0};
+ int indx;
+ ElfW(Addr) got;
+ ElfW(Dyn) *dpnt;
+ struct elf_resolve tpnt_tmp;
+ struct elf_resolve *tpnt = &tpnt_tmp;
+
+ DL_BOOT_COMPUTE_GOT(got);
+ DL_BOOT_COMPUTE_DYN(dpnt, got, (DL_LOADADDR_TYPE)load_addr);
+
+ _dl_memset(tpnt, 0, sizeof(struct elf_resolve));
+ tpnt->loadaddr = load_addr;
+ tpnt->dynamic_addr = dpnt;
+
+ __dl_parse_dynamic_info(dpnt, tpnt->dynamic_info, NULL, load_addr);
+
+#if defined(PERFORM_BOOTSTRAP_GOT)
+ /* some arches (like MIPS) we have to tweak the GOT before relocations */
+ PERFORM_BOOTSTRAP_GOT(tpnt);
+#endif
+
+
+#if defined(ELF_MACHINE_PLTREL_OVERLAP)
+# define INDX_MAX 1
+#else
+# define INDX_MAX 2
+#endif
+
+ for (indx = 0; indx < INDX_MAX; indx++) {
+ unsigned long rel_addr, rel_size;
+ ElfW(Word) relative_count = tpnt->dynamic_info[DT_RELCONT_IDX];
+
+ rel_addr = (indx ? tpnt->dynamic_info[DT_JMPREL] :
+ tpnt->dynamic_info[DT_RELOC_TABLE_ADDR]);
+ rel_size = (indx ? tpnt->dynamic_info[DT_PLTRELSZ] :
+ tpnt->dynamic_info[DT_RELOC_TABLE_SIZE]);
+
+ if (!rel_addr)
+ continue;
- /* Read our own dynamic section and fill in the info array. */
- dyn_addr = ((void *) load_addr + elf_machine_dynamic ());
+ if((0 == indx) && relative_count) {
+ rel_size -= relative_count * sizeof(ELF_RELOC);
+ elf_machine_relative(load_addr, rel_addr, relative_count);
+ rel_addr += relative_count * sizeof(ELF_RELOC);
+ }
- /* Use the underlying function to avoid TLS access before initialization */
- __dl_parse_dynamic_info(dyn_addr, dynamic_info, NULL, load_addr);
+#ifdef ARCH_NEEDS_BOOTSTRAP_RELOCS
+ {
+ ELF_RELOC *rpnt;
+ unsigned int i;
+ ElfW(Sym) *sym;
+ unsigned long symbol_addr;
+ int symtab_index;
+ unsigned long *reloc_addr;
- /* Perform relocations */
- relative_count = dynamic_info[DT_RELCONT_IDX];
- rel_addr = dynamic_info[DT_RELOC_TABLE_ADDR];
- elf_machine_relative(load_addr, rel_addr, relative_count);
+ /* Now parse the relocation information */
+ rpnt = (ELF_RELOC *) rel_addr;
+ for (i = 0; i < rel_size; i += sizeof(ELF_RELOC), rpnt++) {
+ reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_addr, (unsigned long)rpnt->r_offset);
+ symtab_index = ELF_R_SYM(rpnt->r_info);
+ symbol_addr = 0;
+ sym = NULL;
+ if (symtab_index) {
+ ElfW(Sym) *symtab;
+ symtab = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB];
+ sym = &symtab[symtab_index];
+ symbol_addr = (unsigned long) DL_RELOC_ADDR(load_addr, sym->st_value);
+ }
+ /* Use this machine-specific macro to perform the actual relocation. */
+ PERFORM_BOOTSTRAP_RELOC(rpnt, reloc_addr, symbol_addr, load_addr, sym);
+ }
+ }
+#endif
+ }
_dl_load_base = load_addr;
-}
+} \ No newline at end of file