diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/strip.c | 354 |
1 files changed, 9 insertions, 345 deletions
diff --git a/src/strip.c b/src/strip.c index 403e0f6f..a431ebbe 100644 --- a/src/strip.c +++ b/src/strip.c @@ -367,46 +367,6 @@ parse_opt (int key, char *arg, struct argp_state *state) return 0; } -static const char * -secndx_name (Elf *elf, size_t ndx) -{ - size_t shstrndx; - GElf_Shdr mem; - Elf_Scn *sec = elf_getscn (elf, ndx); - GElf_Shdr *shdr = gelf_getshdr (sec, &mem); - if (shdr == NULL || elf_getshdrstrndx (elf, &shstrndx) < 0) - return "???"; - return elf_strptr (elf, shstrndx, shdr->sh_name) ?: "???"; -} - -/* Get the extended section index table data for a symbol table section. */ -static Elf_Data * -get_xndxdata (Elf *elf, Elf_Scn *symscn) -{ - Elf_Data *xndxdata = NULL; - GElf_Shdr shdr_mem; - GElf_Shdr *shdr = gelf_getshdr (symscn, &shdr_mem); - if (shdr != NULL && shdr->sh_type == SHT_SYMTAB) - { - size_t scnndx = elf_ndxscn (symscn); - Elf_Scn *xndxscn = NULL; - while ((xndxscn = elf_nextscn (elf, xndxscn)) != NULL) - { - GElf_Shdr xndxshdr_mem; - GElf_Shdr *xndxshdr = gelf_getshdr (xndxscn, &xndxshdr_mem); - - if (xndxshdr != NULL - && xndxshdr->sh_type == SHT_SYMTAB_SHNDX - && xndxshdr->sh_link == scnndx) - { - xndxdata = elf_getdata (xndxscn, NULL); - break; - } - } - } - - return xndxdata; -} /* Updates the shdrstrndx for the given Elf by updating the Ehdr and possibly the section zero extension field. Returns zero on success. */ @@ -440,306 +400,6 @@ update_shdrstrndx (Elf *elf, size_t shdrstrndx) } -/* Apply one relocation. Returns true when trivial - relocation actually done. */ -static bool -relocate (Elf *elf, GElf_Addr offset, const GElf_Sxword addend, - Elf_Data *tdata, unsigned int ei_data, const char *fname, - bool is_rela, GElf_Sym *sym, int addsub, Elf_Type type) -{ - /* These are the types we can relocate. */ -#define TYPES DO_TYPE (BYTE, Byte); DO_TYPE (HALF, Half); \ - DO_TYPE (WORD, Word); DO_TYPE (SWORD, Sword); \ - DO_TYPE (XWORD, Xword); DO_TYPE (SXWORD, Sxword) - - size_t size; - -#define DO_TYPE(NAME, Name) GElf_##Name Name; - union { TYPES; } tmpbuf; -#undef DO_TYPE - - switch (type) - { -#define DO_TYPE(NAME, Name) \ - case ELF_T_##NAME: \ - size = sizeof (GElf_##Name); \ - tmpbuf.Name = 0; \ - break; - TYPES; -#undef DO_TYPE - default: - return false; - } - - if (offset > tdata->d_size - || tdata->d_size - offset < size) - { - cleanup_debug (); - error_exit (0, _("bad relocation")); - } - - /* When the symbol value is zero then for SHT_REL - sections this is all that needs to be checked. - The addend is contained in the original data at - the offset already. So if the (section) symbol - address is zero and the given addend is zero - just remove the relocation, it isn't needed - anymore. */ - if (addend == 0 && sym->st_value == 0) - return true; - - Elf_Data tmpdata = - { - .d_type = type, - .d_buf = &tmpbuf, - .d_size = size, - .d_version = EV_CURRENT, - }; - Elf_Data rdata = - { - .d_type = type, - .d_buf = tdata->d_buf + offset, - .d_size = size, - .d_version = EV_CURRENT, - }; - - GElf_Addr value = sym->st_value; - if (is_rela) - { - /* For SHT_RELA sections we just take the - given addend and add it to the value. */ - value += addend; - /* For ADD/SUB relocations we need to fetch the - current section contents. */ - if (addsub != 0) - { - Elf_Data *d = gelf_xlatetom (elf, &tmpdata, - &rdata, - ei_data); - if (d == NULL) - INTERNAL_ERROR (fname); - assert (d == &tmpdata); - } - } - else - { - /* For SHT_REL sections we have to peek at - what is already in the section at the given - offset to get the addend. */ - Elf_Data *d = gelf_xlatetom (elf, &tmpdata, - &rdata, - ei_data); - if (d == NULL) - INTERNAL_ERROR (fname); - assert (d == &tmpdata); - } - - switch (type) - { -#define DO_TYPE(NAME, Name) \ - case ELF_T_##NAME: \ - if (addsub < 0) \ - tmpbuf.Name -= (GElf_##Name) value; \ - else \ - tmpbuf.Name += (GElf_##Name) value; \ - break; - TYPES; -#undef DO_TYPE - default: - abort (); - } - - /* Now finally put in the new value. */ - Elf_Data *s = gelf_xlatetof (elf, &rdata, - &tmpdata, - ei_data); - if (s == NULL) - INTERNAL_ERROR (fname); - assert (s == &rdata); - - return true; -} - -/* Remove any relocations between debug sections in ET_REL - for the debug file when requested. These relocations are always - zero based between the unallocated sections. */ -static void -remove_debug_relocations (Ebl *ebl, Elf *elf, GElf_Ehdr *ehdr, - const char *fname, size_t shstrndx) -{ - Elf_Scn *scn = NULL; - while ((scn = elf_nextscn (elf, scn)) != NULL) - { - /* We need the actual section and header from the elf - not just the cached original in shdr_info because we - might want to change the size. */ - GElf_Shdr shdr_mem; - GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); - if (shdr != NULL - && (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA)) - { - /* Make sure that this relocation section points to a - section to relocate with contents, that isn't - allocated and that is a debug section. */ - Elf_Scn *tscn = elf_getscn (elf, shdr->sh_info); - GElf_Shdr tshdr_mem; - GElf_Shdr *tshdr = gelf_getshdr (tscn, &tshdr_mem); - if (tshdr == NULL - || tshdr->sh_type == SHT_NOBITS - || tshdr->sh_size == 0 - || (tshdr->sh_flags & SHF_ALLOC) != 0) - continue; - - const char *tname = elf_strptr (elf, shstrndx, - tshdr->sh_name); - if (! tname || ! ebl_debugscn_p (ebl, tname)) - continue; - - /* OK, lets relocate all trivial cross debug section - relocations. */ - Elf_Data *reldata = elf_getdata (scn, NULL); - if (reldata == NULL || reldata->d_buf == NULL) - INTERNAL_ERROR (fname); - - /* Make sure we adjust the uncompressed debug data - (and recompress if necessary at the end). */ - GElf_Chdr tchdr; - int tcompress_type = 0; - bool is_gnu_compressed = false; - if (startswith (tname, ".zdebug")) - { - is_gnu_compressed = true; - if (elf_compress_gnu (tscn, 0, 0) != 1) - INTERNAL_ERROR (fname); - } - else - { - if (gelf_getchdr (tscn, &tchdr) != NULL) - { - tcompress_type = tchdr.ch_type; - if (elf_compress (tscn, 0, 0) != 1) - INTERNAL_ERROR (fname); - } - } - - Elf_Data *tdata = elf_getdata (tscn, NULL); - if (tdata == NULL || tdata->d_buf == NULL - || tdata->d_type != ELF_T_BYTE) - INTERNAL_ERROR (fname); - - /* Pick up the symbol table and shndx table to - resolve relocation symbol indexes. */ - Elf64_Word symt = shdr->sh_link; - Elf_Data *symdata, *xndxdata; - Elf_Scn * symscn = elf_getscn (elf, symt); - symdata = elf_getdata (symscn, NULL); - xndxdata = get_xndxdata (elf, symscn); - if (symdata == NULL) - INTERNAL_ERROR (fname); - - if (shdr->sh_entsize == 0) - INTERNAL_ERROR (fname); - - size_t nrels = shdr->sh_size / shdr->sh_entsize; - size_t next = 0; - const bool is_rela = (shdr->sh_type == SHT_RELA); - const unsigned int ei_data = ehdr->e_ident[EI_DATA]; - - for (size_t relidx = 0; relidx < nrels; ++relidx) - { - int rtype, symndx, offset, addend; - union { GElf_Rela rela; GElf_Rel rel; } mem; - void *rel_p; /* Pointer to either rela or rel above */ - - if (is_rela) - { - GElf_Rela *r = gelf_getrela (reldata, relidx, &mem.rela); - if (r == NULL) - INTERNAL_ERROR (fname); - offset = r->r_offset; - addend = r->r_addend; - rtype = GELF_R_TYPE (r->r_info); - symndx = GELF_R_SYM (r->r_info); - rel_p = r; - } - else - { - GElf_Rel *r = gelf_getrel (reldata, relidx, &mem.rel); - if (r == NULL) - INTERNAL_ERROR (fname); - offset = r->r_offset; - addend = 0; - rtype = GELF_R_TYPE (r->r_info); - symndx = GELF_R_SYM (r->r_info); - rel_p = r; - } - - /* R_*_NONE relocs can always just be removed. */ - if (rtype == 0) - continue; - - /* We only do simple absolute relocations. */ - int addsub = 0; - Elf_Type type = ebl_reloc_simple_type (ebl, rtype, &addsub); - if (type == ELF_T_NUM) - goto relocate_failed; - - /* And only for relocations against other debug sections. */ - GElf_Sym sym_mem; - Elf32_Word xndx; - GElf_Sym *sym = gelf_getsymshndx (symdata, xndxdata, - symndx, &sym_mem, - &xndx); - if (sym == NULL) - INTERNAL_ERROR (fname); - Elf32_Word sec = (sym->st_shndx == SHN_XINDEX - ? xndx : sym->st_shndx); - - bool dbg_scn = ebl_debugscn_p (ebl, secndx_name (elf, sec)); - - if (!dbg_scn) - goto relocate_failed; - - if (! relocate (elf, offset, addend, - tdata, ei_data, fname, is_rela, - sym, addsub, type)) - goto relocate_failed; - - continue; /* Next */ - -relocate_failed: - if (relidx != next) - { - int updated; - if (is_rela) - updated = gelf_update_rela (reldata, next, rel_p); - else - updated = gelf_update_rel (reldata, next, rel_p); - if (updated == 0) - INTERNAL_ERROR (fname); - } - ++next; - } - - nrels = next; - shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize; - if (gelf_update_shdr (scn, shdr) == 0) - INTERNAL_ERROR (fname); - - if (is_gnu_compressed) - { - if (elf_compress_gnu (tscn, 1, ELF_CHF_FORCE) != 1) - INTERNAL_ERROR (fname); - } - else if (tcompress_type != 0) - { - if (elf_compress (tscn, tcompress_type, ELF_CHF_FORCE) != 1) - INTERNAL_ERROR (fname); - } - } - } -} - static int process_file (const char *fname) { @@ -839,7 +499,7 @@ process_file (const char *fname) /* Processing for --reloc-debug-sections-only. */ static int -handle_debug_relocs (Elf *elf, Ebl *ebl, Elf *new_elf, +handle_debug_relocs (Elf *elf, Elf *new_elf, GElf_Ehdr *ehdr, const char *fname, size_t shstrndx, GElf_Off *last_offset, GElf_Xword *last_size) { @@ -910,8 +570,9 @@ handle_debug_relocs (Elf *elf, Ebl *ebl, Elf *new_elf, return 1; } - /* Adjust the relocation sections. */ - remove_debug_relocations (ebl, new_elf, ehdr, fname, shstrndx); + /* Remove debug section relocations. */ + if (dwelf_elf_remove_debug_relocations (new_elf) == -1) + INTERNAL_ERROR (fname); /* Adjust the offsets of the non-allocated sections, so they come after the allocated sections. */ @@ -1139,7 +800,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, if (reloc_debug_only) { - if (handle_debug_relocs (elf, ebl, newelf, ehdr, fname, shstrndx, + if (handle_debug_relocs (elf, newelf, ehdr, fname, shstrndx, &lastsec_offset, &lastsec_size) != 0) { result = 1; @@ -2457,7 +2118,10 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, zero based between the unallocated sections. */ if (debug_fname != NULL && removing_sections && reloc_debug && ehdr->e_type == ET_REL) - remove_debug_relocations (ebl, debugelf, ehdr, fname, shstrndx); + { + if (dwelf_elf_remove_debug_relocations (debugelf) == -1) + INTERNAL_ERROR (fname); + } /* Now that we have done all adjustments to the data, we can actually write out the debug file. */ |