diff options
Diffstat (limited to 'src/strip.c')
| -rw-r--r-- | src/strip.c | 874 |
1 files changed, 558 insertions, 316 deletions
diff --git a/src/strip.c b/src/strip.c index a85a2306..15a43ff7 100644 --- a/src/strip.c +++ b/src/strip.c @@ -1,5 +1,5 @@ /* Discard section not used at runtime from object files. - Copyright (C) 2000-2012, 2014, 2015, 2016, 2017 Red Hat, Inc. + Copyright (C) 2000-2012, 2014, 2015, 2016, 2017, 2018 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper <drepper@redhat.com>, 2000. @@ -61,6 +61,7 @@ ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT; #define OPT_STRIP_SECTIONS 0x102 #define OPT_RELOC_DEBUG 0x103 #define OPT_KEEP_SECTION 0x104 +#define OPT_RELOC_DEBUG_ONLY 0x105 /* Definitions of arguments for argp functions. */ @@ -82,6 +83,8 @@ static const struct argp_option options[] = N_("Copy modified/access timestamps to the output"), 0 }, { "reloc-debug-sections", OPT_RELOC_DEBUG, NULL, 0, N_("Resolve all trivial relocations between debug sections if the removed sections are placed in a debug file (only relevant for ET_REL files, operation is not reversable, needs -f)"), 0 }, + { "reloc-debug-sections-only", OPT_RELOC_DEBUG_ONLY, NULL, 0, + N_("Similar to --reloc-debug-sections, but resolve all trivial relocations between debug sections in place. No other stripping is performed (operation is not reversable, incompatible with -f, -g, --remove-comment and --remove-section)"), 0 }, { "remove-comment", OPT_REMOVE_COMMENT, NULL, 0, N_("Remove .comment section"), 0 }, { "remove-section", 'R', "SECTION", 0, N_("Remove the named section. SECTION is an extended wildcard pattern. May be given more than once. Only non-allocated sections can be removed."), 0 }, @@ -159,6 +162,9 @@ static bool permissive; /* If true perform relocations between debug sections. */ static bool reloc_debug; +/* If true perform relocations between debug sections only. */ +static bool reloc_debug_only; + /* Sections the user explicitly wants to keep or remove. */ struct section_pattern { @@ -240,6 +246,12 @@ main (int argc, char *argv[]) error (EXIT_FAILURE, 0, gettext ("--reloc-debug-sections used without -f")); + if (reloc_debug_only && + (debug_fname != NULL || remove_secs != NULL + || remove_comment == true || remove_debug == true)) + error (EXIT_FAILURE, 0, + gettext ("--reloc-debug-sections-only incompatible with -f, -g, --remove-comment and --remove-section")); + /* Tell the library which version we are expecting. */ elf_version (EV_CURRENT); @@ -307,6 +319,10 @@ parse_opt (int key, char *arg, struct argp_state *state) reloc_debug = true; break; + case OPT_RELOC_DEBUG_ONLY: + reloc_debug_only = true; + break; + case OPT_REMOVE_COMMENT: remove_comment = true; break; @@ -354,6 +370,345 @@ 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. */ +static int +update_shdrstrndx (Elf *elf, size_t shdrstrndx) +{ + GElf_Ehdr ehdr; + if (gelf_getehdr (elf, &ehdr) == 0) + return 1; + + if (shdrstrndx < SHN_LORESERVE) + ehdr.e_shstrndx = shdrstrndx; + else + { + ehdr.e_shstrndx = SHN_XINDEX; + Elf_Scn *scn0 = elf_getscn (elf, 0); + GElf_Shdr shdr0_mem; + GElf_Shdr *shdr0 = gelf_getshdr (scn0, &shdr0_mem); + if (shdr0 == NULL) + return 1; + + shdr0->sh_link = shdrstrndx; + if (gelf_update_shdr (scn0, shdr0) == 0) + return 1; + } + + if (unlikely (gelf_update_ehdr (elf, &ehdr) == 0)) + return 1; + + return 0; +} + +/* 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->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->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 (strncmp (tname, ".zdebug", strlen ("zdebug")) == 0) + { + 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); + + /* Apply one relocation. Returns true when trivial + relocation actually done. */ + bool relocate (GElf_Addr offset, const GElf_Sxword addend, + bool is_rela, int rtype, int symndx) + { + /* R_*_NONE relocs can always just be removed. */ + if (rtype == 0) + return true; + + /* We only do simple absolute relocations. */ + int addsub = 0; + Elf_Type type = ebl_reloc_simple_type (ebl, rtype, &addsub); + if (type == ELF_T_NUM) + return false; + + /* 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) + + /* 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); + Elf32_Word sec = (sym->st_shndx == SHN_XINDEX + ? xndx : sym->st_shndx); + + if (ebl_debugscn_p (ebl, secndx_name (elf, sec))) + { + 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_FAILURE, 0, gettext ("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, + ehdr->e_ident[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, + ehdr->e_ident[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, + ehdr->e_ident[EI_DATA]); + if (s == NULL) + INTERNAL_ERROR (fname); + assert (s == &rdata); + + return true; + } + return false; + } + + if (shdr->sh_entsize == 0) + INTERNAL_ERROR (fname); + + size_t nrels = shdr->sh_size / shdr->sh_entsize; + size_t next = 0; + if (shdr->sh_type == SHT_REL) + for (size_t relidx = 0; relidx < nrels; ++relidx) + { + GElf_Rel rel_mem; + GElf_Rel *r = gelf_getrel (reldata, relidx, &rel_mem); + if (! relocate (r->r_offset, 0, false, + GELF_R_TYPE (r->r_info), + GELF_R_SYM (r->r_info))) + { + if (relidx != next) + gelf_update_rel (reldata, next, r); + ++next; + } + } + else + for (size_t relidx = 0; relidx < nrels; ++relidx) + { + GElf_Rela rela_mem; + GElf_Rela *r = gelf_getrela (reldata, relidx, &rela_mem); + if (! relocate (r->r_offset, r->r_addend, true, + GELF_R_TYPE (r->r_info), + GELF_R_SYM (r->r_info))) + { + if (relidx != next) + gelf_update_rela (reldata, next, r); + ++next; + } + } + + nrels = next; + shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize; + gelf_update_shdr (scn, shdr); + + 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) @@ -444,6 +799,116 @@ process_file (const char *fname) return result; } +/* Processing for --reloc-debug-sections-only. */ +static int +handle_debug_relocs (Elf *elf, Ebl *ebl, Elf *new_elf, + GElf_Ehdr *ehdr, const char *fname, size_t shstrndx, + GElf_Off *last_offset, GElf_Xword *last_size) +{ + + /* Copy over the ELF header. */ + if (gelf_update_ehdr (new_elf, ehdr) == 0) + { + error (0, 0, "couldn't update new ehdr: %s", elf_errmsg (-1)); + return 1; + } + + /* Copy over sections and record end of allocated sections. */ + GElf_Off lastoffset = 0; + Elf_Scn *scn = NULL; + while ((scn = elf_nextscn (elf, scn)) != NULL) + { + /* Get the header. */ + GElf_Shdr shdr; + if (gelf_getshdr (scn, &shdr) == NULL) + { + error (0, 0, "couldn't get shdr: %s", elf_errmsg (-1)); + return 1; + } + + /* Create new section. */ + Elf_Scn *new_scn = elf_newscn (new_elf); + if (new_scn == NULL) + { + error (0, 0, "couldn't create new section: %s", elf_errmsg (-1)); + return 1; + } + + if (gelf_update_shdr (new_scn, &shdr) == 0) + { + error (0, 0, "couldn't update shdr: %s", elf_errmsg (-1)); + return 1; + } + + /* Copy over section data. */ + Elf_Data *data = NULL; + while ((data = elf_getdata (scn, data)) != NULL) + { + Elf_Data *new_data = elf_newdata (new_scn); + if (new_data == NULL) + { + error (0, 0, "couldn't create new section data: %s", + elf_errmsg (-1)); + return 1; + } + *new_data = *data; + } + + /* Record last offset of allocated section. */ + if ((shdr.sh_flags & SHF_ALLOC) != 0) + { + GElf_Off filesz = (shdr.sh_type != SHT_NOBITS + ? shdr.sh_size : 0); + if (lastoffset < shdr.sh_offset + filesz) + lastoffset = shdr.sh_offset + filesz; + } + } + + /* Make sure section header name table is setup correctly, we'll + need it to determine whether to relocate sections. */ + if (update_shdrstrndx (new_elf, shstrndx) != 0) + { + error (0, 0, "error updating shdrstrndx: %s", elf_errmsg (-1)); + return 1; + } + + /* Adjust the relocation sections. */ + remove_debug_relocations (ebl, new_elf, ehdr, fname, shstrndx); + + /* Adjust the offsets of the non-allocated sections, so they come after + the allocated sections. */ + scn = NULL; + while ((scn = elf_nextscn (new_elf, scn)) != NULL) + { + /* Get the header. */ + GElf_Shdr shdr; + if (gelf_getshdr (scn, &shdr) == NULL) + { + error (0, 0, "couldn't get shdr: %s", elf_errmsg (-1)); + return 1; + } + + /* Adjust non-allocated section offsets to be after any allocated. */ + if ((shdr.sh_flags & SHF_ALLOC) == 0) + { + shdr.sh_offset = ((lastoffset + shdr.sh_addralign - 1) + & ~((GElf_Off) (shdr.sh_addralign - 1))); + if (gelf_update_shdr (scn, &shdr) == 0) + { + error (0, 0, "couldn't update shdr: %s", elf_errmsg (-1)); + return 1; + } + + GElf_Off filesz = (shdr.sh_type != SHT_NOBITS + ? shdr.sh_size : 0); + lastoffset = shdr.sh_offset + filesz; + *last_offset = shdr.sh_offset; + *last_size = filesz; + } + } + + return 0; +} /* Maximum size of array allocated on stack. */ #define MAX_STACK_ALLOC (400 * 1024) @@ -460,6 +925,8 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, tmp_debug_fname = NULL; int result = 0; size_t shdridx = 0; + GElf_Off lastsec_offset = 0; + Elf64_Xword lastsec_size = 0; size_t shstrndx; struct shdr_info { @@ -518,7 +985,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, the --reloc-debug-sections option are currently the only reasons we need EBL so don't open the backend unless necessary. */ Ebl *ebl = NULL; - if (remove_debug || reloc_debug) + if (remove_debug || reloc_debug || reloc_debug_only) { ebl = ebl_openbackend (elf); if (ebl == NULL) @@ -580,49 +1047,75 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, else newelf = elf_clone (elf, ELF_C_EMPTY); - if (unlikely (gelf_newehdr (newelf, gelf_getclass (elf)) == 0) - || (ehdr->e_type != ET_REL - && unlikely (gelf_newphdr (newelf, phnum) == 0))) + if (unlikely (gelf_newehdr (newelf, gelf_getclass (elf)) == 0)) { - error (0, 0, gettext ("cannot create new file '%s': %s"), + error (0, 0, gettext ("cannot create new ehdr for file '%s': %s"), output_fname ?: fname, elf_errmsg (-1)); goto fail; } /* Copy over the old program header if needed. */ - if (ehdr->e_type != ET_REL) - for (cnt = 0; cnt < phnum; ++cnt) - { - GElf_Phdr phdr_mem; - GElf_Phdr *phdr = gelf_getphdr (elf, cnt, &phdr_mem); - if (phdr == NULL - || unlikely (gelf_update_phdr (newelf, cnt, phdr) == 0)) - INTERNAL_ERROR (fname); - } + if (phnum > 0) + { + if (unlikely (gelf_newphdr (newelf, phnum) == 0)) + { + error (0, 0, gettext ("cannot create new phdr for file '%s': %s"), + output_fname ?: fname, elf_errmsg (-1)); + goto fail; + } + + for (cnt = 0; cnt < phnum; ++cnt) + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr = gelf_getphdr (elf, cnt, &phdr_mem); + if (phdr == NULL + || unlikely (gelf_update_phdr (newelf, cnt, phdr) == 0)) + INTERNAL_ERROR (fname); + } + } + + if (reloc_debug_only) + { + if (handle_debug_relocs (elf, ebl, newelf, ehdr, fname, shstrndx, + &lastsec_offset, &lastsec_size) != 0) + { + result = 1; + goto fail_close; + } + idx = shstrndx; + goto done; /* Skip all actual stripping operations. */ + } if (debug_fname != NULL) { /* Also create an ELF descriptor for the debug file */ debugelf = elf_begin (debug_fd, ELF_C_WRITE_MMAP, NULL); - if (unlikely (gelf_newehdr (debugelf, gelf_getclass (elf)) == 0) - || (ehdr->e_type != ET_REL - && unlikely (gelf_newphdr (debugelf, phnum) == 0))) + if (unlikely (gelf_newehdr (debugelf, gelf_getclass (elf)) == 0)) { - error (0, 0, gettext ("cannot create new file '%s': %s"), + error (0, 0, gettext ("cannot create new ehdr for file '%s': %s"), debug_fname, elf_errmsg (-1)); goto fail_close; } /* Copy over the old program header if needed. */ - if (ehdr->e_type != ET_REL) - for (cnt = 0; cnt < phnum; ++cnt) - { - GElf_Phdr phdr_mem; - GElf_Phdr *phdr = gelf_getphdr (elf, cnt, &phdr_mem); - if (phdr == NULL - || unlikely (gelf_update_phdr (debugelf, cnt, phdr) == 0)) - INTERNAL_ERROR (fname); - } + if (phnum > 0) + { + if (unlikely (gelf_newphdr (debugelf, phnum) == 0)) + { + error (0, 0, gettext ("cannot create new phdr for file '%s': %s"), + debug_fname, elf_errmsg (-1)); + goto fail_close; + } + + for (cnt = 0; cnt < phnum; ++cnt) + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr = gelf_getphdr (elf, cnt, &phdr_mem); + if (phdr == NULL + || unlikely (gelf_update_phdr (debugelf, cnt, phdr) == 0)) + INTERNAL_ERROR (fname); + } + } } /* Number of sections. */ @@ -730,7 +1223,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, to keep the layout of all allocated sections as similar as possible to the original file. In relocatable object files everything can be moved. */ - if (ehdr->e_type == ET_REL + if (phnum == 0 || (shdr_info[cnt].shdr.sh_flags & SHF_ALLOC) == 0) shdr_info[cnt].shdr.sh_offset = 0; @@ -784,9 +1277,13 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, if (shdr_info[shdr_info[cnt].group_idx].idx == 0) { - /* The section group section will be removed. */ + /* The section group section might be removed. + Don't remove the SHF_GROUP flag. The section is + either also removed, in which case the flag doesn't matter. + Or it moves with the group into the debug file, then + it will be reconnected with the new group and should + still have the flag set. */ shdr_info[cnt].group_idx = 0; - shdr_info[cnt].shdr.sh_flags &= ~SHF_GROUP; } } @@ -1127,6 +1624,14 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, debugehdr->e_entry = ehdr->e_entry; debugehdr->e_flags = ehdr->e_flags; + if (unlikely (gelf_update_ehdr (debugelf, debugehdr) == 0)) + { + error (0, 0, gettext ("%s: error while updating ELF header: %s"), + debug_fname, elf_errmsg (-1)); + result = 1; + goto fail_close; + } + size_t shdrstrndx; if (elf_getshdrstrndx (elf, &shdrstrndx) < 0) { @@ -1136,36 +1641,9 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, goto fail_close; } - if (shstrndx < SHN_LORESERVE) - debugehdr->e_shstrndx = shdrstrndx; - else + if (update_shdrstrndx (debugelf, shdrstrndx) != 0) { - debugehdr->e_shstrndx = SHN_XINDEX; - Elf_Scn *scn0 = elf_getscn (debugelf, 0); - GElf_Shdr shdr0_mem; - GElf_Shdr *shdr0 = gelf_getshdr (scn0, &shdr0_mem); - if (shdr0 == NULL) - { - error (0, 0, gettext ("%s: error getting zero section: %s"), - debug_fname, elf_errmsg (-1)); - result = 1; - goto fail_close; - } - - shdr0->sh_link = shdrstrndx; - if (gelf_update_shdr (scn0, shdr0) == 0) - { - error (0, 0, gettext ("%s: error while updating zero section: %s"), - debug_fname, elf_errmsg (-1)); - result = 1; - goto fail_close; - } - - } - - if (unlikely (gelf_update_ehdr (debugelf, debugehdr) == 0)) - { - error (0, 0, gettext ("%s: error while creating ELF header: %s"), + error (0, 0, gettext ("%s: error updating shdrstrndx: %s"), debug_fname, elf_errmsg (-1)); result = 1; goto fail_close; @@ -1360,7 +1838,9 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, && shdr_info[cnt].data->d_buf != NULL); Elf32_Word *grpref = (Elf32_Word *) shdr_info[cnt].data->d_buf; - for (size_t inner = 0; + /* First word is the section group flag. + Followed by section indexes, that need to be renumbered. */ + for (size_t inner = 1; inner < shdr_info[cnt].data->d_size / sizeof (Elf32_Word); ++inner) if (grpref[inner] < shnum) @@ -1950,240 +2430,7 @@ 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) - { - scn = NULL; - cnt = 0; - while ((scn = elf_nextscn (debugelf, scn)) != NULL) - { - cnt++; - /* We need the actual section and header from the debugelf - 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->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 (debugelf, shdr->sh_info); - GElf_Shdr tshdr_mem; - GElf_Shdr *tshdr = gelf_getshdr (tscn, &tshdr_mem); - if (tshdr->sh_type == SHT_NOBITS - || tshdr->sh_size == 0 - || (tshdr->sh_flags & SHF_ALLOC) != 0) - continue; - - const char *tname = elf_strptr (debugelf, 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; - 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_assert (symt < shnum + 2); - elf_assert (shdr_info[symt].symtab_idx < shnum + 2); - symdata = (shdr_info[symt].debug_data - ?: shdr_info[symt].data); - xndxdata = (shdr_info[shdr_info[symt].symtab_idx].debug_data - ?: shdr_info[shdr_info[symt].symtab_idx].data); - - /* Apply one relocation. Returns true when trivial - relocation actually done. */ - bool relocate (GElf_Addr offset, const GElf_Sxword addend, - bool is_rela, int rtype, int symndx) - { - /* R_*_NONE relocs can always just be removed. */ - if (rtype == 0) - return true; - - /* We only do simple absolute relocations. */ - Elf_Type type = ebl_reloc_simple_type (ebl, rtype); - if (type == ELF_T_NUM) - return false; - - /* 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) - - /* 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); - Elf32_Word sec = (sym->st_shndx == SHN_XINDEX - ? xndx : sym->st_shndx); - if (sec >= shnum + 2) - INTERNAL_ERROR (fname); - - if (ebl_debugscn_p (ebl, shdr_info[sec].name)) - { - 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_FAILURE, 0, gettext ("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; - } - 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 (debugelf, &tmpdata, - &rdata, - ehdr->e_ident[EI_DATA]); - if (d == NULL) - INTERNAL_ERROR (fname); - assert (d == &tmpdata); - } - - switch (type) - { -#define DO_TYPE(NAME, Name) \ - case ELF_T_##NAME: \ - tmpbuf.Name += (GElf_##Name) value; \ - break; - TYPES; -#undef DO_TYPE - default: - abort (); - } - - /* Now finally put in the new value. */ - Elf_Data *s = gelf_xlatetof (debugelf, &rdata, - &tmpdata, - ehdr->e_ident[EI_DATA]); - if (s == NULL) - INTERNAL_ERROR (fname); - assert (s == &rdata); - - return true; - } - return false; - } - - if (shdr->sh_entsize == 0) - INTERNAL_ERROR (fname); - - size_t nrels = shdr->sh_size / shdr->sh_entsize; - size_t next = 0; - if (shdr->sh_type == SHT_REL) - for (size_t relidx = 0; relidx < nrels; ++relidx) - { - GElf_Rel rel_mem; - GElf_Rel *r = gelf_getrel (reldata, relidx, &rel_mem); - if (! relocate (r->r_offset, 0, false, - GELF_R_TYPE (r->r_info), - GELF_R_SYM (r->r_info))) - { - if (relidx != next) - gelf_update_rel (reldata, next, r); - ++next; - } - } - else - for (size_t relidx = 0; relidx < nrels; ++relidx) - { - GElf_Rela rela_mem; - GElf_Rela *r = gelf_getrela (reldata, relidx, &rela_mem); - if (! relocate (r->r_offset, r->r_addend, true, - GELF_R_TYPE (r->r_info), - GELF_R_SYM (r->r_info))) - { - if (relidx != next) - gelf_update_rela (reldata, next, r); - ++next; - } - } - - nrels = next; - shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize; - gelf_update_shdr (scn, shdr); - - if (tcompress_type != 0) - if (elf_compress (tscn, tcompress_type, ELF_CHF_FORCE) != 1) - INTERNAL_ERROR (fname); - } - } - } + remove_debug_relocations (ebl, debugelf, ehdr, fname, shstrndx); /* Now that we have done all adjustments to the data, we can actually write out the debug file. */ @@ -2247,6 +2494,10 @@ while computing checksum for debug information")); } } + lastsec_offset = shdr_info[shdridx].shdr.sh_offset; + lastsec_size = shdr_info[shdridx].shdr.sh_size; + + done: /* Finally finish the ELF header. Fill in the fields not handled by libelf from the old file. */ newehdr = gelf_getehdr (newelf, &newehdr_mem); @@ -2263,31 +2514,22 @@ while computing checksum for debug information")); /* We need to position the section header table. */ const size_t offsize = gelf_fsize (elf, ELF_T_OFF, 1, EV_CURRENT); - newehdr->e_shoff = ((shdr_info[shdridx].shdr.sh_offset - + shdr_info[shdridx].shdr.sh_size + offsize - 1) + newehdr->e_shoff = ((lastsec_offset + lastsec_size + offsize - 1) & ~((GElf_Off) (offsize - 1))); newehdr->e_shentsize = gelf_fsize (elf, ELF_T_SHDR, 1, EV_CURRENT); - /* The new section header string table index. */ - if (likely (idx < SHN_HIRESERVE) && likely (idx != SHN_XINDEX)) - newehdr->e_shstrndx = idx; - else + if (gelf_update_ehdr (newelf, newehdr) == 0) { - /* The index does not fit in the ELF header field. */ - shdr_info[0].scn = elf_getscn (elf, 0); - - if (gelf_getshdr (shdr_info[0].scn, &shdr_info[0].shdr) == NULL) - INTERNAL_ERROR (fname); - - shdr_info[0].shdr.sh_link = idx; - (void) gelf_update_shdr (shdr_info[0].scn, &shdr_info[0].shdr); - - newehdr->e_shstrndx = SHN_XINDEX; + error (0, 0, gettext ("%s: error while creating ELF header: %s"), + output_fname ?: fname, elf_errmsg (-1)); + cleanup_debug (); + return 1; } - if (gelf_update_ehdr (newelf, newehdr) == 0) + /* The new section header string table index. */ + if (update_shdrstrndx (newelf, idx) != 0) { - error (0, 0, gettext ("%s: error while creating ELF header: %s"), + error (0, 0, gettext ("%s: error updating shdrstrndx: %s"), output_fname ?: fname, elf_errmsg (-1)); cleanup_debug (); return 1; @@ -2305,7 +2547,7 @@ while computing checksum for debug information")); /* The ELF library better follows our layout when this is not a relocatable object file. */ elf_flagelf (newelf, ELF_C_SET, - (ehdr->e_type != ET_REL ? ELF_F_LAYOUT : 0) + (phnum > 0 ? ELF_F_LAYOUT : 0) | (permissive ? ELF_F_PERMISSIVE : 0)); /* Finally write the file. */ @@ -2334,7 +2576,7 @@ while computing checksum for debug information")); || (pwrite_retry (fd, zero, sizeof zero, offsetof (Elf32_Ehdr, e_shentsize)) != sizeof zero) - || ftruncate (fd, shdr_info[shdridx].shdr.sh_offset) < 0) + || ftruncate (fd, lastsec_offset) < 0) { error (0, errno, gettext ("while writing '%s'"), output_fname ?: fname); @@ -2354,7 +2596,7 @@ while computing checksum for debug information")); || (pwrite_retry (fd, zero, sizeof zero, offsetof (Elf64_Ehdr, e_shentsize)) != sizeof zero) - || ftruncate (fd, shdr_info[shdridx].shdr.sh_offset) < 0) + || ftruncate (fd, lastsec_offset) < 0) { error (0, errno, gettext ("while writing '%s'"), output_fname ?: fname); |