diff options
Diffstat (limited to 'src/strip.c')
| -rw-r--r-- | src/strip.c | 1884 |
1 files changed, 1884 insertions, 0 deletions
diff --git a/src/strip.c b/src/strip.c new file mode 100644 index 0000000..99374eb --- /dev/null +++ b/src/strip.c @@ -0,0 +1,1884 @@ +/* Discard section not used at runtime from object files. + Copyright (C) 2000-2011 Red Hat, Inc. + This file is part of Red Hat elfutils. + Written by Ulrich Drepper <drepper@redhat.com>, 2000. + + Red Hat elfutils is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by the + Free Software Foundation; version 2 of the License. + + Red Hat elfutils 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License along + with Red Hat elfutils; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. + + Red Hat elfutils is an included package of the Open Invention Network. + An included package of the Open Invention Network is a package for which + Open Invention Network licensees cross-license their patents. No patent + license is granted, either expressly or impliedly, by designation as an + included package. Should you wish to participate in the Open Invention + Network licensing program, please visit www.openinventionnetwork.com + <http://www.openinventionnetwork.com>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <argp.h> +#include <assert.h> +#include <byteswap.h> +#include <endian.h> +#include <error.h> +#include <fcntl.h> +#include <gelf.h> +#include <libelf.h> +#include <libintl.h> +#include <locale.h> +#include <mcheck.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdio_ext.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/param.h> +#include <sys/stat.h> +#include <sys/time.h> + +#include <elf-knowledge.h> +#include <libebl.h> +#include <system.h> + + +/* Name and version of program. */ +static void print_version (FILE *stream, struct argp_state *state); +ARGP_PROGRAM_VERSION_HOOK_DEF = print_version; + +/* Bug report address. */ +ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT; + + +/* Values for the parameters which have no short form. */ +#define OPT_REMOVE_COMMENT 0x100 +#define OPT_PERMISSIVE 0x101 +#define OPT_STRIP_SECTIONS 0x102 + + +/* Definitions of arguments for argp functions. */ +static const struct argp_option options[] = +{ + { NULL, 0, NULL, 0, N_("Output selection:"), 0 }, + { "output", 'o', "FILE", 0, N_("Place stripped output into FILE"), 0 }, + { NULL, 'f', "FILE", 0, N_("Extract the removed sections into FILE"), 0 }, + { NULL, 'F', "FILE", 0, N_("Embed name FILE instead of -f argument"), 0 }, + + { NULL, 0, NULL, 0, N_("Output options:"), 0 }, + { "strip-all", 's', NULL, OPTION_HIDDEN, NULL, 0 }, + { "strip-debug", 'g', NULL, 0, N_("Remove all debugging symbols"), 0 }, + { NULL, 'd', NULL, OPTION_ALIAS, NULL, 0 }, + { NULL, 'S', NULL, OPTION_ALIAS, NULL, 0 }, + { "strip-sections", OPT_STRIP_SECTIONS, NULL, 0, + N_("Remove section headers (not recommended)"), 0 }, + { "preserve-dates", 'p', NULL, 0, + N_("Copy modified/access timestamps to the output"), 0 }, + { "remove-comment", OPT_REMOVE_COMMENT, NULL, 0, + N_("Remove .comment section"), 0 }, + { "remove-section", 'R', "SECTION", OPTION_HIDDEN, NULL, 0 }, + { "permissive", OPT_PERMISSIVE, NULL, 0, + N_("Relax a few rules to handle slightly broken ELF files"), 0 }, + { NULL, 0, NULL, 0, NULL, 0 } +}; + +/* Short description of program. */ +static const char doc[] = N_("Discard symbols from object files."); + +/* Strings for arguments in help texts. */ +static const char args_doc[] = N_("[FILE...]"); + +/* Prototype for option handler. */ +static error_t parse_opt (int key, char *arg, struct argp_state *state); + +/* Data structure to communicate with argp functions. */ +static struct argp argp = +{ + options, parse_opt, args_doc, doc, NULL, NULL, NULL +}; + + +/* Print symbols in file named FNAME. */ +static int process_file (const char *fname); + +/* Handle one ELF file. */ +static int handle_elf (int fd, Elf *elf, const char *prefix, + const char *fname, mode_t mode, struct timeval tvp[2]); + +/* Handle all files contained in the archive. */ +static int handle_ar (int fd, Elf *elf, const char *prefix, const char *fname, + struct timeval tvp[2]); + +#define INTERNAL_ERROR(fname) \ + error (EXIT_FAILURE, 0, gettext ("%s: INTERNAL ERROR %d (%s-%s): %s"), \ + fname, __LINE__, PACKAGE_VERSION, __DATE__, elf_errmsg (-1)) + + +/* Name of the output file. */ +static const char *output_fname; + +/* Name of the debug output file. */ +static const char *debug_fname; + +/* Name to pretend the debug output file has. */ +static const char *debug_fname_embed; + +/* If true output files shall have same date as the input file. */ +static bool preserve_dates; + +/* If true .comment sections will be removed. */ +static bool remove_comment; + +/* If true remove all debug sections. */ +static bool remove_debug; + +/* If true remove all section headers. */ +static bool remove_shdrs; + +/* If true relax some ELF rules for input files. */ +static bool permissive; + + +int +main (int argc, char *argv[]) +{ + int remaining; + int result = 0; + + /* Make memory leak detection possible. */ + mtrace (); + + /* We use no threads here which can interfere with handling a stream. */ + __fsetlocking (stdin, FSETLOCKING_BYCALLER); + __fsetlocking (stdout, FSETLOCKING_BYCALLER); + __fsetlocking (stderr, FSETLOCKING_BYCALLER); + + /* Set locale. */ + setlocale (LC_ALL, ""); + + /* Make sure the message catalog can be found. */ + bindtextdomain (PACKAGE_TARNAME, LOCALEDIR); + + /* Initialize the message catalog. */ + textdomain (PACKAGE_TARNAME); + + /* Parse and process arguments. */ + if (argp_parse (&argp, argc, argv, 0, &remaining, NULL) != 0) + return EXIT_FAILURE; + + /* Tell the library which version we are expecting. */ + elf_version (EV_CURRENT); + + if (remaining == argc) + /* The user didn't specify a name so we use a.out. */ + result = process_file ("a.out"); + else + { + /* If we have seen the '-o' or '-f' option there must be exactly one + input file. */ + if ((output_fname != NULL || debug_fname != NULL) + && remaining + 1 < argc) + error (EXIT_FAILURE, 0, gettext ("\ +Only one input file allowed together with '-o' and '-f'")); + + /* Process all the remaining files. */ + do + result |= process_file (argv[remaining]); + while (++remaining < argc); + } + + return result; +} + + +/* Print the version information. */ +static void +print_version (FILE *stream, struct argp_state *state __attribute__ ((unused))) +{ + fprintf (stream, "strip (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION); + fprintf (stream, gettext ("\ +Copyright (C) %s Red Hat, Inc.\n\ +This is free software; see the source for copying conditions. There is NO\n\ +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\ +"), "2009"); + fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper"); +} + + +/* Handle program arguments. */ +static error_t +parse_opt (int key, char *arg, struct argp_state *state) +{ + switch (key) + { + case 'f': + if (debug_fname != NULL) + { + error (0, 0, gettext ("-f option specified twice")); + return EINVAL; + } + debug_fname = arg; + break; + + case 'F': + if (debug_fname_embed != NULL) + { + error (0, 0, gettext ("-F option specified twice")); + return EINVAL; + } + debug_fname_embed = arg; + break; + + case 'o': + if (output_fname != NULL) + { + error (0, 0, gettext ("-o option specified twice")); + return EINVAL; + } + output_fname = arg; + break; + + case 'p': + preserve_dates = true; + break; + + case OPT_REMOVE_COMMENT: + remove_comment = true; + break; + + case 'R': + if (!strcmp (arg, ".comment")) + remove_comment = true; + else + { + argp_error (state, + gettext ("-R option supports only .comment section")); + return EINVAL; + } + break; + + case 'g': + case 'd': + case 'S': + remove_debug = true; + break; + + case OPT_STRIP_SECTIONS: + remove_shdrs = true; + break; + + case OPT_PERMISSIVE: + permissive = true; + break; + + case 's': /* Ignored for compatibility. */ + break; + + default: + return ARGP_ERR_UNKNOWN; + } + return 0; +} + + +static int +process_file (const char *fname) +{ + /* If we have to preserve the modify and access timestamps get them + now. We cannot use fstat() after opening the file since the open + would change the access time. */ + struct stat64 pre_st; + struct timeval tv[2]; + again: + if (preserve_dates) + { + if (stat64 (fname, &pre_st) != 0) + { + error (0, errno, gettext ("cannot stat input file '%s'"), fname); + return 1; + } + + /* If we have to preserve the timestamp, we need it in the + format utimes() understands. */ + TIMESPEC_TO_TIMEVAL (&tv[0], &pre_st.st_atim); + TIMESPEC_TO_TIMEVAL (&tv[1], &pre_st.st_mtim); + } + + /* Open the file. */ + int fd = open (fname, output_fname == NULL ? O_RDWR : O_RDONLY); + if (fd == -1) + { + error (0, errno, gettext ("while opening '%s'"), fname); + return 1; + } + + /* We always use fstat() even if we called stat() before. This is + done to make sure the information returned by stat() is for the + same file. */ + struct stat64 st; + if (fstat64 (fd, &st) != 0) + { + error (0, errno, gettext ("cannot stat input file '%s'"), fname); + return 1; + } + /* Paranoid mode on. */ + if (preserve_dates + && (st.st_ino != pre_st.st_ino || st.st_dev != pre_st.st_dev)) + { + /* We detected a race. Try again. */ + close (fd); + goto again; + } + + /* Now get the ELF descriptor. */ + Elf *elf = elf_begin (fd, output_fname == NULL ? ELF_C_RDWR : ELF_C_READ, + NULL); + int result; + switch (elf_kind (elf)) + { + case ELF_K_ELF: + result = handle_elf (fd, elf, NULL, fname, st.st_mode & ACCESSPERMS, + preserve_dates ? tv : NULL); + break; + + case ELF_K_AR: + /* It is not possible to strip the content of an archive direct + the output to a specific file. */ + if (unlikely (output_fname != NULL || debug_fname != NULL)) + { + error (0, 0, gettext ("%s: cannot use -o or -f when stripping archive"), + fname); + result = 1; + } + else + result = handle_ar (fd, elf, NULL, fname, preserve_dates ? tv : NULL); + break; + + default: + error (0, 0, gettext ("%s: File format not recognized"), fname); + result = 1; + break; + } + + if (unlikely (elf_end (elf) != 0)) + INTERNAL_ERROR (fname); + + close (fd); + + return result; +} + + +/* Maximum size of array allocated on stack. */ +#define MAX_STACK_ALLOC (400 * 1024) + +static int +handle_elf (int fd, Elf *elf, const char *prefix, const char *fname, + mode_t mode, struct timeval tvp[2]) +{ + size_t prefix_len = prefix == NULL ? 0 : strlen (prefix); + size_t fname_len = strlen (fname) + 1; + char *fullname = alloca (prefix_len + 1 + fname_len); + char *cp = fullname; + Elf *debugelf = NULL; + char *tmp_debug_fname = NULL; + int result = 0; + size_t shdridx = 0; + size_t shstrndx; + struct shdr_info + { + Elf_Scn *scn; + GElf_Shdr shdr; + Elf_Data *data; + Elf_Data *debug_data; + const char *name; + Elf32_Word idx; /* Index in new file. */ + Elf32_Word old_sh_link; /* Original value of shdr.sh_link. */ + Elf32_Word symtab_idx; + Elf32_Word version_idx; + Elf32_Word group_idx; + Elf32_Word group_cnt; + Elf_Scn *newscn; + struct Ebl_Strent *se; + Elf32_Word *newsymidx; + } *shdr_info = NULL; + Elf_Scn *scn; + size_t cnt; + size_t idx; + bool changes; + GElf_Ehdr newehdr_mem; + GElf_Ehdr *newehdr; + GElf_Ehdr debugehdr_mem; + GElf_Ehdr *debugehdr; + struct Ebl_Strtab *shst = NULL; + Elf_Data debuglink_crc_data; + bool any_symtab_changes = false; + Elf_Data *shstrtab_data = NULL; + + /* Create the full name of the file. */ + if (prefix != NULL) + { + cp = mempcpy (cp, prefix, prefix_len); + *cp++ = ':'; + } + memcpy (cp, fname, fname_len); + + /* If we are not replacing the input file open a new file here. */ + if (output_fname != NULL) + { + fd = open (output_fname, O_RDWR | O_CREAT, mode); + if (unlikely (fd == -1)) + { + error (0, errno, gettext ("cannot open '%s'"), output_fname); + return 1; + } + } + + int debug_fd = -1; + + /* Get the EBL handling. The -g option is currently the only reason + we need EBL so don't open the backend unless necessary. */ + Ebl *ebl = NULL; + if (remove_debug) + { + ebl = ebl_openbackend (elf); + if (ebl == NULL) + { + error (0, errno, gettext ("cannot open EBL backend")); + result = 1; + goto fail; + } + } + + /* Open the additional file the debug information will be stored in. */ + if (debug_fname != NULL) + { + /* Create a temporary file name. We do not want to overwrite + the debug file if the file would not contain any + information. */ + size_t debug_fname_len = strlen (debug_fname); + tmp_debug_fname = (char *) alloca (debug_fname_len + sizeof (".XXXXXX")); + strcpy (mempcpy (tmp_debug_fname, debug_fname, debug_fname_len), + ".XXXXXX"); + + debug_fd = mkstemp (tmp_debug_fname); + if (unlikely (debug_fd == -1)) + { + error (0, errno, gettext ("cannot open '%s'"), debug_fname); + result = 1; + goto fail; + } + } + + /* Get the information from the old file. */ + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); + if (ehdr == NULL) + INTERNAL_ERROR (fname); + + /* Get the section header string table index. */ + if (unlikely (elf_getshdrstrndx (elf, &shstrndx) < 0)) + error (EXIT_FAILURE, 0, + gettext ("cannot get section header string table index")); + + /* We now create a new ELF descriptor for the same file. We + construct it almost exactly in the same way with some information + dropped. */ + Elf *newelf; + if (output_fname != NULL) + newelf = elf_begin (fd, ELF_C_WRITE_MMAP, NULL); + 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, ehdr->e_phnum) == 0))) + { + error (0, 0, gettext ("cannot create new file '%s': %s"), + output_fname, elf_errmsg (-1)); + goto fail; + } + + /* Copy over the old program header if needed. */ + if (ehdr->e_type != ET_REL) + for (cnt = 0; cnt < ehdr->e_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 (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, ehdr->e_phnum) == 0))) + { + error (0, 0, gettext ("cannot create new 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 < ehdr->e_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. */ + size_t shnum; + if (unlikely (elf_getshdrnum (elf, &shnum) < 0)) + { + error (0, 0, gettext ("cannot determine number of sections: %s"), + elf_errmsg (-1)); + goto fail_close; + } + + /* Storage for section information. We leave room for two more + entries since we unconditionally create a section header string + table. Maybe some weird tool created an ELF file without one. + The other one is used for the debug link section. */ + if ((shnum + 2) * sizeof (struct shdr_info) > MAX_STACK_ALLOC) + shdr_info = (struct shdr_info *) xcalloc (shnum + 2, + sizeof (struct shdr_info)); + else + { + shdr_info = (struct shdr_info *) alloca ((shnum + 2) + * sizeof (struct shdr_info)); + memset (shdr_info, '\0', (shnum + 2) * sizeof (struct shdr_info)); + } + + /* Prepare section information data structure. */ + scn = NULL; + cnt = 1; + while ((scn = elf_nextscn (elf, scn)) != NULL) + { + /* This should always be true (i.e., there should not be any + holes in the numbering). */ + assert (elf_ndxscn (scn) == cnt); + + shdr_info[cnt].scn = scn; + + /* Get the header. */ + if (gelf_getshdr (scn, &shdr_info[cnt].shdr) == NULL) + INTERNAL_ERROR (fname); + + /* Get the name of the section. */ + shdr_info[cnt].name = elf_strptr (elf, shstrndx, + shdr_info[cnt].shdr.sh_name); + if (shdr_info[cnt].name == NULL) + { + error (0, 0, gettext ("illformed file '%s'"), fname); + goto fail_close; + } + + /* Mark them as present but not yet investigated. */ + shdr_info[cnt].idx = 1; + + /* Remember the shdr.sh_link value. */ + shdr_info[cnt].old_sh_link = shdr_info[cnt].shdr.sh_link; + + /* Sections in files other than relocatable object files which + are not loaded can be freely moved by us. In relocatable + object files everything can be moved. */ + if (ehdr->e_type == ET_REL + || (shdr_info[cnt].shdr.sh_flags & SHF_ALLOC) == 0) + shdr_info[cnt].shdr.sh_offset = 0; + + /* If this is an extended section index table store an + appropriate reference. */ + if (unlikely (shdr_info[cnt].shdr.sh_type == SHT_SYMTAB_SHNDX)) + { + assert (shdr_info[shdr_info[cnt].shdr.sh_link].symtab_idx == 0); + shdr_info[shdr_info[cnt].shdr.sh_link].symtab_idx = cnt; + } + else if (unlikely (shdr_info[cnt].shdr.sh_type == SHT_GROUP)) + { + /* Cross-reference the sections contained in the section + group. */ + shdr_info[cnt].data = elf_getdata (shdr_info[cnt].scn, NULL); + if (shdr_info[cnt].data == NULL) + INTERNAL_ERROR (fname); + + /* XXX Fix for unaligned access. */ + Elf32_Word *grpref = (Elf32_Word *) shdr_info[cnt].data->d_buf; + size_t inner; + for (inner = 1; + inner < shdr_info[cnt].data->d_size / sizeof (Elf32_Word); + ++inner) + shdr_info[grpref[inner]].group_idx = cnt; + + if (inner == 1 || (inner == 2 && (grpref[0] & GRP_COMDAT) == 0)) + /* If the section group contains only one element and this + is n COMDAT section we can drop it right away. */ + shdr_info[cnt].idx = 0; + else + shdr_info[cnt].group_cnt = inner - 1; + } + else if (unlikely (shdr_info[cnt].shdr.sh_type == SHT_GNU_versym)) + { + assert (shdr_info[shdr_info[cnt].shdr.sh_link].version_idx == 0); + shdr_info[shdr_info[cnt].shdr.sh_link].version_idx = cnt; + } + + /* If this section is part of a group make sure it is not + discarded right away. */ + if ((shdr_info[cnt].shdr.sh_flags & SHF_GROUP) != 0) + { + assert (shdr_info[cnt].group_idx != 0); + + if (shdr_info[shdr_info[cnt].group_idx].idx == 0) + { + /* The section group section will be removed. */ + shdr_info[cnt].group_idx = 0; + shdr_info[cnt].shdr.sh_flags &= ~SHF_GROUP; + } + } + + /* Increment the counter. */ + ++cnt; + } + + /* Now determine which sections can go away. The general rule is that + all sections which are not used at runtime are stripped out. But + there are a few exceptions: + + - special sections named ".comment" and ".note" are kept + - OS or architecture specific sections are kept since we might not + know how to handle them + - if a section is referred to from a section which is not removed + in the sh_link or sh_info element it cannot be removed either + */ + for (cnt = 1; cnt < shnum; ++cnt) + /* Check whether the section can be removed. */ + if (remove_shdrs ? !(shdr_info[cnt].shdr.sh_flags & SHF_ALLOC) + : ebl_section_strip_p (ebl, ehdr, &shdr_info[cnt].shdr, + shdr_info[cnt].name, remove_comment, + remove_debug)) + { + /* For now assume this section will be removed. */ + shdr_info[cnt].idx = 0; + + idx = shdr_info[cnt].group_idx; + while (idx != 0) + { + /* The section group data is already loaded. */ + assert (shdr_info[idx].data != NULL); + + /* If the references section group is a normal section + group and has one element remaining, or if it is an + empty COMDAT section group it is removed. */ + bool is_comdat = (((Elf32_Word *) shdr_info[idx].data->d_buf)[0] + & GRP_COMDAT) != 0; + + --shdr_info[idx].group_cnt; + if ((!is_comdat && shdr_info[idx].group_cnt == 1) + || (is_comdat && shdr_info[idx].group_cnt == 0)) + { + shdr_info[idx].idx = 0; + /* Continue recursively. */ + idx = shdr_info[idx].group_idx; + } + else + break; + } + } + + /* Mark the SHT_NULL section as handled. */ + shdr_info[0].idx = 2; + + + /* Handle exceptions: section groups and cross-references. We might + have to repeat this a few times since the resetting of the flag + might propagate. */ + do + { + changes = false; + + for (cnt = 1; cnt < shnum; ++cnt) + { + if (shdr_info[cnt].idx == 0) + { + /* If a relocation section is marked as being removed make + sure the section it is relocating is removed, too. */ + if ((shdr_info[cnt].shdr.sh_type == SHT_REL + || shdr_info[cnt].shdr.sh_type == SHT_RELA) + && shdr_info[shdr_info[cnt].shdr.sh_info].idx != 0) + shdr_info[cnt].idx = 1; + } + + if (shdr_info[cnt].idx == 1) + { + /* The content of symbol tables we don't remove must not + reference any section which we do remove. Otherwise + we cannot remove the section. */ + if (debug_fname != NULL + && shdr_info[cnt].debug_data == NULL + && (shdr_info[cnt].shdr.sh_type == SHT_DYNSYM + || shdr_info[cnt].shdr.sh_type == SHT_SYMTAB)) + { + /* Make sure the data is loaded. */ + if (shdr_info[cnt].data == NULL) + { + shdr_info[cnt].data + = elf_getdata (shdr_info[cnt].scn, NULL); + if (shdr_info[cnt].data == NULL) + INTERNAL_ERROR (fname); + } + Elf_Data *symdata = shdr_info[cnt].data; + + /* If there is an extended section index table load it + as well. */ + if (shdr_info[cnt].symtab_idx != 0 + && shdr_info[shdr_info[cnt].symtab_idx].data == NULL) + { + assert (shdr_info[cnt].shdr.sh_type == SHT_SYMTAB); + + shdr_info[shdr_info[cnt].symtab_idx].data + = elf_getdata (shdr_info[shdr_info[cnt].symtab_idx].scn, + NULL); + if (shdr_info[shdr_info[cnt].symtab_idx].data == NULL) + INTERNAL_ERROR (fname); + } + Elf_Data *xndxdata + = shdr_info[shdr_info[cnt].symtab_idx].data; + + /* Go through all symbols and make sure the section they + reference is not removed. */ + size_t elsize = gelf_fsize (elf, ELF_T_SYM, 1, + ehdr->e_version); + + for (size_t inner = 0; + inner < shdr_info[cnt].data->d_size / elsize; + ++inner) + { + GElf_Sym sym_mem; + Elf32_Word xndx; + GElf_Sym *sym = gelf_getsymshndx (symdata, xndxdata, + inner, &sym_mem, + &xndx); + if (sym == NULL) + INTERNAL_ERROR (fname); + + size_t scnidx = sym->st_shndx; + if (scnidx == SHN_UNDEF || scnidx >= shnum + || (scnidx >= SHN_LORESERVE + && scnidx <= SHN_HIRESERVE + && scnidx != SHN_XINDEX) + /* Don't count in the section symbols. */ + || GELF_ST_TYPE (sym->st_info) == STT_SECTION) + /* This is no section index, leave it alone. */ + continue; + else if (scnidx == SHN_XINDEX) + scnidx = xndx; + + if (shdr_info[scnidx].idx == 0) + /* This symbol table has a real symbol in + a discarded section. So preserve the + original table in the debug file. */ + shdr_info[cnt].debug_data = symdata; + } + } + + /* Cross referencing happens: + - for the cases the ELF specification says. That are + + SHT_DYNAMIC in sh_link to string table + + SHT_HASH in sh_link to symbol table + + SHT_REL and SHT_RELA in sh_link to symbol table + + SHT_SYMTAB and SHT_DYNSYM in sh_link to string table + + SHT_GROUP in sh_link to symbol table + + SHT_SYMTAB_SHNDX in sh_link to symbol table + Other (OS or architecture-specific) sections might as + well use this field so we process it unconditionally. + - references inside section groups + - specially marked references in sh_info if the SHF_INFO_LINK + flag is set + */ + + if (shdr_info[shdr_info[cnt].shdr.sh_link].idx == 0) + { + shdr_info[shdr_info[cnt].shdr.sh_link].idx = 1; + changes |= shdr_info[cnt].shdr.sh_link < cnt; + } + + /* Handle references through sh_info. */ + if (SH_INFO_LINK_P (&shdr_info[cnt].shdr) + && shdr_info[shdr_info[cnt].shdr.sh_info].idx == 0) + { + shdr_info[shdr_info[cnt].shdr.sh_info].idx = 1; + changes |= shdr_info[cnt].shdr.sh_info < cnt; + } + + /* Mark the section as investigated. */ + shdr_info[cnt].idx = 2; + } + + if (debug_fname != NULL + && (shdr_info[cnt].idx == 0 || shdr_info[cnt].debug_data != NULL)) + { + /* This section is being preserved in the debug file. + Sections it refers to must be preserved there too. + + In this pass we mark sections to be preserved in both + files by setting the .debug_data pointer to the original + file's .data pointer. Below, we'll copy the section + contents. */ + + inline void check_preserved (size_t i) + { + if (i != 0 && shdr_info[i].idx != 0 + && shdr_info[i].debug_data == NULL) + { + if (shdr_info[i].data == NULL) + shdr_info[i].data = elf_getdata (shdr_info[i].scn, NULL); + if (shdr_info[i].data == NULL) + INTERNAL_ERROR (fname); + + shdr_info[i].debug_data = shdr_info[i].data; + changes |= i < cnt; + } + } + + check_preserved (shdr_info[cnt].shdr.sh_link); + if (SH_INFO_LINK_P (&shdr_info[cnt].shdr)) + check_preserved (shdr_info[cnt].shdr.sh_info); + } + } + } + while (changes); + + /* Copy the removed sections to the debug output file. + The ones that are not removed in the stripped file are SHT_NOBITS. */ + if (debug_fname != NULL) + { + for (cnt = 1; cnt < shnum; ++cnt) + { + scn = elf_newscn (debugelf); + if (scn == NULL) + error (EXIT_FAILURE, 0, + gettext ("while generating output file: %s"), + elf_errmsg (-1)); + + bool discard_section = (shdr_info[cnt].idx > 0 + && shdr_info[cnt].debug_data == NULL + && shdr_info[cnt].shdr.sh_type != SHT_NOTE + && cnt != ehdr->e_shstrndx); + + /* Set the section header in the new file. */ + GElf_Shdr debugshdr = shdr_info[cnt].shdr; + if (discard_section) + debugshdr.sh_type = SHT_NOBITS; + + if (unlikely (gelf_update_shdr (scn, &debugshdr) == 0)) + /* There cannot be any overflows. */ + INTERNAL_ERROR (fname); + + /* Get the data from the old file if necessary. */ + if (shdr_info[cnt].data == NULL) + { + shdr_info[cnt].data = elf_getdata (shdr_info[cnt].scn, NULL); + if (shdr_info[cnt].data == NULL) + INTERNAL_ERROR (fname); + } + + /* Set the data. This is done by copying from the old file. */ + Elf_Data *debugdata = elf_newdata (scn); + if (debugdata == NULL) + INTERNAL_ERROR (fname); + + /* Copy the structure. This data may be modified in place + before we write out the file. */ + *debugdata = *shdr_info[cnt].data; + if (discard_section) + debugdata->d_buf = NULL; + else if (shdr_info[cnt].debug_data != NULL) + { + /* Copy the original data before it gets modified. */ + shdr_info[cnt].debug_data = debugdata; + debugdata->d_buf = memcpy (xmalloc (debugdata->d_size), + debugdata->d_buf, debugdata->d_size); + } + } + + /* Finish the ELF header. Fill in the fields not handled by + libelf from the old file. */ + debugehdr = gelf_getehdr (debugelf, &debugehdr_mem); + if (debugehdr == NULL) + INTERNAL_ERROR (fname); + + memcpy (debugehdr->e_ident, ehdr->e_ident, EI_NIDENT); + debugehdr->e_type = ehdr->e_type; + debugehdr->e_machine = ehdr->e_machine; + debugehdr->e_version = ehdr->e_version; + debugehdr->e_entry = ehdr->e_entry; + debugehdr->e_flags = ehdr->e_flags; + debugehdr->e_shstrndx = ehdr->e_shstrndx; + + if (unlikely (gelf_update_ehdr (debugelf, debugehdr) == 0)) + { + error (0, 0, gettext ("%s: error while creating ELF header: %s"), + debug_fname, elf_errmsg (-1)); + result = 1; + goto fail_close; + } + } + + /* Mark the section header string table as unused, we will create + a new one. */ + shdr_info[shstrndx].idx = 0; + + /* We need a string table for the section headers. */ + shst = ebl_strtabinit (true); + if (shst == NULL) + error (EXIT_FAILURE, errno, gettext ("while preparing output for '%s'"), + output_fname ?: fname); + + /* Assign new section numbers. */ + shdr_info[0].idx = 0; + for (cnt = idx = 1; cnt < shnum; ++cnt) + if (shdr_info[cnt].idx > 0) + { + shdr_info[cnt].idx = idx++; + + /* Create a new section. */ + shdr_info[cnt].newscn = elf_newscn (newelf); + if (shdr_info[cnt].newscn == NULL) + error (EXIT_FAILURE, 0, gettext ("while generating output file: %s"), + elf_errmsg (-1)); + + assert (elf_ndxscn (shdr_info[cnt].newscn) == shdr_info[cnt].idx); + + /* Add this name to the section header string table. */ + shdr_info[cnt].se = ebl_strtabadd (shst, shdr_info[cnt].name, 0); + } + + /* Test whether we are doing anything at all. */ + if (cnt == idx) + /* Nope, all removable sections are already gone. */ + goto fail_close; + + /* Create the reference to the file with the debug info. */ + if (debug_fname != NULL && !remove_shdrs) + { + /* Add the section header string table section name. */ + shdr_info[cnt].se = ebl_strtabadd (shst, ".gnu_debuglink", 15); + shdr_info[cnt].idx = idx++; + + /* Create the section header. */ + shdr_info[cnt].shdr.sh_type = SHT_PROGBITS; + shdr_info[cnt].shdr.sh_flags = 0; + shdr_info[cnt].shdr.sh_addr = 0; + shdr_info[cnt].shdr.sh_link = SHN_UNDEF; + shdr_info[cnt].shdr.sh_info = SHN_UNDEF; + shdr_info[cnt].shdr.sh_entsize = 0; + shdr_info[cnt].shdr.sh_addralign = 4; + /* We set the offset to zero here. Before we write the ELF file the + field must have the correct value. This is done in the final + loop over all section. Then we have all the information needed. */ + shdr_info[cnt].shdr.sh_offset = 0; + + /* Create the section. */ + shdr_info[cnt].newscn = elf_newscn (newelf); + if (shdr_info[cnt].newscn == NULL) + error (EXIT_FAILURE, 0, + gettext ("while create section header section: %s"), + elf_errmsg (-1)); + assert (elf_ndxscn (shdr_info[cnt].newscn) == shdr_info[cnt].idx); + + shdr_info[cnt].data = elf_newdata (shdr_info[cnt].newscn); + if (shdr_info[cnt].data == NULL) + error (EXIT_FAILURE, 0, gettext ("cannot allocate section data: %s"), + elf_errmsg (-1)); + + char *debug_basename = basename (debug_fname_embed ?: debug_fname); + off_t crc_offset = strlen (debug_basename) + 1; + /* Align to 4 byte boundary */ + crc_offset = ((crc_offset - 1) & ~3) + 4; + + shdr_info[cnt].data->d_align = 4; + shdr_info[cnt].shdr.sh_size = shdr_info[cnt].data->d_size + = crc_offset + 4; + shdr_info[cnt].data->d_buf = xcalloc (1, shdr_info[cnt].data->d_size); + + strcpy (shdr_info[cnt].data->d_buf, debug_basename); + + /* Cache this Elf_Data describing the CRC32 word in the section. + We'll fill this in when we have written the debug file. */ + debuglink_crc_data = *shdr_info[cnt].data; + debuglink_crc_data.d_buf = ((char *) debuglink_crc_data.d_buf + + crc_offset); + debuglink_crc_data.d_size = 4; + + /* One more section done. */ + ++cnt; + } + + /* Index of the section header table in the shdr_info array. */ + shdridx = cnt; + + /* Add the section header string table section name. */ + shdr_info[cnt].se = ebl_strtabadd (shst, ".shstrtab", 10); + shdr_info[cnt].idx = idx; + + /* Create the section header. */ + shdr_info[cnt].shdr.sh_type = SHT_STRTAB; + shdr_info[cnt].shdr.sh_flags = 0; + shdr_info[cnt].shdr.sh_addr = 0; + shdr_info[cnt].shdr.sh_link = SHN_UNDEF; + shdr_info[cnt].shdr.sh_info = SHN_UNDEF; + shdr_info[cnt].shdr.sh_entsize = 0; + /* We set the offset to zero here. Before we write the ELF file the + field must have the correct value. This is done in the final + loop over all section. Then we have all the information needed. */ + shdr_info[cnt].shdr.sh_offset = 0; + shdr_info[cnt].shdr.sh_addralign = 1; + + /* Create the section. */ + shdr_info[cnt].newscn = elf_newscn (newelf); + if (shdr_info[cnt].newscn == NULL) + error (EXIT_FAILURE, 0, + gettext ("while create section header section: %s"), + elf_errmsg (-1)); + assert (elf_ndxscn (shdr_info[cnt].newscn) == idx); + + /* Finalize the string table and fill in the correct indices in the + section headers. */ + shstrtab_data = elf_newdata (shdr_info[cnt].newscn); + if (shstrtab_data == NULL) + error (EXIT_FAILURE, 0, + gettext ("while create section header string table: %s"), + elf_errmsg (-1)); + ebl_strtabfinalize (shst, shstrtab_data); + + /* We have to set the section size. */ + shdr_info[cnt].shdr.sh_size = shstrtab_data->d_size; + + /* Update the section information. */ + GElf_Off lastoffset = 0; + for (cnt = 1; cnt <= shdridx; ++cnt) + if (shdr_info[cnt].idx > 0) + { + Elf_Data *newdata; + + scn = elf_getscn (newelf, shdr_info[cnt].idx); + assert (scn != NULL); + + /* Update the name. */ + shdr_info[cnt].shdr.sh_name = ebl_strtaboffset (shdr_info[cnt].se); + + /* Update the section header from the input file. Some fields + might be section indeces which now have to be adjusted. */ + if (shdr_info[cnt].shdr.sh_link != 0) + shdr_info[cnt].shdr.sh_link = + shdr_info[shdr_info[cnt].shdr.sh_link].idx; + + if (shdr_info[cnt].shdr.sh_type == SHT_GROUP) + { + assert (shdr_info[cnt].data != NULL); + + Elf32_Word *grpref = (Elf32_Word *) shdr_info[cnt].data->d_buf; + for (size_t inner = 0; + inner < shdr_info[cnt].data->d_size / sizeof (Elf32_Word); + ++inner) + grpref[inner] = shdr_info[grpref[inner]].idx; + } + + /* Handle the SHT_REL, SHT_RELA, and SHF_INFO_LINK flag. */ + if (SH_INFO_LINK_P (&shdr_info[cnt].shdr)) + shdr_info[cnt].shdr.sh_info = + shdr_info[shdr_info[cnt].shdr.sh_info].idx; + + /* Get the data from the old file if necessary. We already + created the data for the section header string table. */ + if (cnt < shnum) + { + if (shdr_info[cnt].data == NULL) + { + shdr_info[cnt].data = elf_getdata (shdr_info[cnt].scn, NULL); + if (shdr_info[cnt].data == NULL) + INTERNAL_ERROR (fname); + } + + /* Set the data. This is done by copying from the old file. */ + newdata = elf_newdata (scn); + if (newdata == NULL) + INTERNAL_ERROR (fname); + + /* Copy the structure. */ + *newdata = *shdr_info[cnt].data; + + /* We know the size. */ + shdr_info[cnt].shdr.sh_size = shdr_info[cnt].data->d_size; + + /* We have to adjust symbol tables. The st_shndx member might + have to be updated. */ + if (shdr_info[cnt].shdr.sh_type == SHT_DYNSYM + || shdr_info[cnt].shdr.sh_type == SHT_SYMTAB) + { + Elf_Data *versiondata = NULL; + Elf_Data *shndxdata = NULL; + + size_t elsize = gelf_fsize (elf, ELF_T_SYM, 1, + ehdr->e_version); + + if (shdr_info[cnt].symtab_idx != 0) + { + assert (shdr_info[cnt].shdr.sh_type == SHT_SYMTAB_SHNDX); + /* This section has extended section information. + We have to modify that information, too. */ + shndxdata = elf_getdata (shdr_info[shdr_info[cnt].symtab_idx].scn, + NULL); + + assert ((versiondata->d_size / sizeof (Elf32_Word)) + >= shdr_info[cnt].data->d_size / elsize); + } + + if (shdr_info[cnt].version_idx != 0) + { + assert (shdr_info[cnt].shdr.sh_type == SHT_DYNSYM); + /* This section has associated version + information. We have to modify that + information, too. */ + versiondata = elf_getdata (shdr_info[shdr_info[cnt].version_idx].scn, + NULL); + + assert ((versiondata->d_size / sizeof (GElf_Versym)) + >= shdr_info[cnt].data->d_size / elsize); + } + + shdr_info[cnt].newsymidx + = (Elf32_Word *) xcalloc (shdr_info[cnt].data->d_size + / elsize, sizeof (Elf32_Word)); + + bool last_was_local = true; + size_t destidx; + size_t inner; + for (destidx = inner = 1; + inner < shdr_info[cnt].data->d_size / elsize; + ++inner) + { + Elf32_Word sec; + GElf_Sym sym_mem; + Elf32_Word xshndx; + GElf_Sym *sym = gelf_getsymshndx (shdr_info[cnt].data, + shndxdata, inner, + &sym_mem, &xshndx); + if (sym == NULL) + INTERNAL_ERROR (fname); + + if (sym->st_shndx == SHN_UNDEF + || (sym->st_shndx >= shnum + && sym->st_shndx != SHN_XINDEX)) + { + /* This is no section index, leave it alone + unless it is moved. */ + if (destidx != inner + && gelf_update_symshndx (shdr_info[cnt].data, + shndxdata, + destidx, sym, + xshndx) == 0) + INTERNAL_ERROR (fname); + + shdr_info[cnt].newsymidx[inner] = destidx++; + + if (last_was_local + && GELF_ST_BIND (sym->st_info) != STB_LOCAL) + { + last_was_local = false; + shdr_info[cnt].shdr.sh_info = destidx - 1; + } + + continue; + } + + /* Get the full section index, if necessary from the + XINDEX table. */ + if (sym->st_shndx != SHN_XINDEX) + sec = shdr_info[sym->st_shndx].idx; + else + { + assert (shndxdata != NULL); + + sec = shdr_info[xshndx].idx; + } + + if (sec != 0) + { + GElf_Section nshndx; + Elf32_Word nxshndx; + + if (sec < SHN_LORESERVE) + { + nshndx = sec; + nxshndx = 0; + } + else + { + nshndx = SHN_XINDEX; + nxshndx = sec; + } + + assert (sec < SHN_LORESERVE || shndxdata != NULL); + + if ((inner != destidx || nshndx != sym->st_shndx + || (shndxdata != NULL && nxshndx != xshndx)) + && (sym->st_shndx = nshndx, + gelf_update_symshndx (shdr_info[cnt].data, + shndxdata, + destidx, sym, + nxshndx) == 0)) + INTERNAL_ERROR (fname); + + shdr_info[cnt].newsymidx[inner] = destidx++; + + if (last_was_local + && GELF_ST_BIND (sym->st_info) != STB_LOCAL) + { + last_was_local = false; + shdr_info[cnt].shdr.sh_info = destidx - 1; + } + } + else if (debug_fname == NULL + || shdr_info[cnt].debug_data == NULL) + /* This is a section symbol for a section which has + been removed. */ + assert (GELF_ST_TYPE (sym->st_info) == STT_SECTION); + } + + if (destidx != inner) + { + /* The size of the symbol table changed. */ + shdr_info[cnt].shdr.sh_size = newdata->d_size + = destidx * elsize; + any_symtab_changes = true; + } + else + { + /* The symbol table didn't really change. */ + free (shdr_info[cnt].newsymidx); + shdr_info[cnt].newsymidx = NULL; + } + } + } + + /* If we have to, compute the offset of the section. */ + if (shdr_info[cnt].shdr.sh_offset == 0) + shdr_info[cnt].shdr.sh_offset + = ((lastoffset + shdr_info[cnt].shdr.sh_addralign - 1) + & ~((GElf_Off) (shdr_info[cnt].shdr.sh_addralign - 1))); + + /* Set the section header in the new file. */ + if (unlikely (gelf_update_shdr (scn, &shdr_info[cnt].shdr) == 0)) + /* There cannot be any overflows. */ + INTERNAL_ERROR (fname); + + /* Remember the last section written so far. */ + GElf_Off filesz = (shdr_info[cnt].shdr.sh_type != SHT_NOBITS + ? shdr_info[cnt].shdr.sh_size : 0); + if (lastoffset < shdr_info[cnt].shdr.sh_offset + filesz) + lastoffset = shdr_info[cnt].shdr.sh_offset + filesz; + } + + /* Adjust symbol references if symbol tables changed. */ + if (any_symtab_changes) + /* Find all relocation sections which use this symbol table. */ + for (cnt = 1; cnt <= shdridx; ++cnt) + { + /* Update section headers when the data size has changed. + We also update the SHT_NOBITS section in the debug + file so that the section headers match in sh_size. */ + inline void update_section_size (const Elf_Data *newdata) + { + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + shdr->sh_size = newdata->d_size; + (void) gelf_update_shdr (scn, shdr); + if (debugelf != NULL) + { + /* libelf will use d_size to set sh_size. */ + Elf_Data *debugdata = elf_getdata (elf_getscn (debugelf, + cnt), NULL); + debugdata->d_size = newdata->d_size; + } + } + + if (shdr_info[cnt].idx == 0 && debug_fname == NULL) + /* Ignore sections which are discarded. When we are saving a + relocation section in a separate debug file, we must fix up + the symbol table references. */ + continue; + + const Elf32_Word symtabidx = shdr_info[cnt].old_sh_link; + const Elf32_Word *const newsymidx = shdr_info[symtabidx].newsymidx; + switch (shdr_info[cnt].shdr.sh_type) + { + inline bool no_symtab_updates (void) + { + /* If the symbol table hasn't changed, do not do anything. */ + if (shdr_info[symtabidx].newsymidx == NULL) + return true; + + /* If the symbol table is not discarded, but additionally + duplicated in the separate debug file and this section + is discarded, don't adjust anything. */ + return (shdr_info[cnt].idx == 0 + && shdr_info[symtabidx].debug_data != NULL); + } + + case SHT_REL: + case SHT_RELA: + if (no_symtab_updates ()) + break; + + Elf_Data *d = elf_getdata (shdr_info[cnt].idx == 0 + ? elf_getscn (debugelf, cnt) + : elf_getscn (newelf, + shdr_info[cnt].idx), + NULL); + assert (d != NULL); + size_t nrels = (shdr_info[cnt].shdr.sh_size + / shdr_info[cnt].shdr.sh_entsize); + + if (shdr_info[cnt].shdr.sh_type == SHT_REL) + for (size_t relidx = 0; relidx < nrels; ++relidx) + { + GElf_Rel rel_mem; + if (gelf_getrel (d, relidx, &rel_mem) == NULL) + INTERNAL_ERROR (fname); + + size_t symidx = GELF_R_SYM (rel_mem.r_info); + if (newsymidx[symidx] != symidx) + { + rel_mem.r_info + = GELF_R_INFO (newsymidx[symidx], + GELF_R_TYPE (rel_mem.r_info)); + + if (gelf_update_rel (d, relidx, &rel_mem) == 0) + INTERNAL_ERROR (fname); + } + } + else + for (size_t relidx = 0; relidx < nrels; ++relidx) + { + GElf_Rela rel_mem; + if (gelf_getrela (d, relidx, &rel_mem) == NULL) + INTERNAL_ERROR (fname); + + size_t symidx = GELF_R_SYM (rel_mem.r_info); + if (newsymidx[symidx] != symidx) + { + rel_mem.r_info + = GELF_R_INFO (newsymidx[symidx], + GELF_R_TYPE (rel_mem.r_info)); + + if (gelf_update_rela (d, relidx, &rel_mem) == 0) + INTERNAL_ERROR (fname); + } + } + break; + + case SHT_HASH: + if (no_symtab_updates ()) + break; + + /* We have to recompute the hash table. */ + + assert (shdr_info[cnt].idx > 0); + + /* The hash section in the new file. */ + scn = elf_getscn (newelf, shdr_info[cnt].idx); + + /* The symbol table data. */ + Elf_Data *symd = elf_getdata (elf_getscn (newelf, + shdr_info[symtabidx].idx), + NULL); + assert (symd != NULL); + + /* The hash table data. */ + Elf_Data *hashd = elf_getdata (scn, NULL); + assert (hashd != NULL); + + if (shdr_info[cnt].shdr.sh_entsize == sizeof (Elf32_Word)) + { + /* Sane arches first. */ + Elf32_Word *bucket = (Elf32_Word *) hashd->d_buf; + + size_t strshndx = shdr_info[symtabidx].old_sh_link; + size_t elsize = gelf_fsize (elf, ELF_T_SYM, 1, + ehdr->e_version); + + /* Adjust the nchain value. The symbol table size + changed. We keep the same size for the bucket array. */ + bucket[1] = symd->d_size / elsize; + Elf32_Word nbucket = bucket[0]; + bucket += 2; + Elf32_Word *chain = bucket + nbucket; + + /* New size of the section. */ + hashd->d_size = ((2 + symd->d_size / elsize + nbucket) + * sizeof (Elf32_Word)); + update_section_size (hashd); + + /* Clear the arrays. */ + memset (bucket, '\0', + (symd->d_size / elsize + nbucket) + * sizeof (Elf32_Word)); + + for (size_t inner = shdr_info[symtabidx].shdr.sh_info; + inner < symd->d_size / elsize; ++inner) + { + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symd, inner, &sym_mem); + assert (sym != NULL); + + const char *name = elf_strptr (elf, strshndx, + sym->st_name); + assert (name != NULL); + size_t hidx = elf_hash (name) % nbucket; + + if (bucket[hidx] == 0) + bucket[hidx] = inner; + else + { + hidx = bucket[hidx]; + + while (chain[hidx] != 0) + hidx = chain[hidx]; + + chain[hidx] = inner; + } + } + } + else + { + /* Alpha and S390 64-bit use 64-bit SHT_HASH entries. */ + assert (shdr_info[cnt].shdr.sh_entsize + == sizeof (Elf64_Xword)); + + Elf64_Xword *bucket = (Elf64_Xword *) hashd->d_buf; + + size_t strshndx = shdr_info[symtabidx].old_sh_link; + size_t elsize = gelf_fsize (elf, ELF_T_SYM, 1, + ehdr->e_version); + + /* Adjust the nchain value. The symbol table size + changed. We keep the same size for the bucket array. */ + bucket[1] = symd->d_size / elsize; + Elf64_Xword nbucket = bucket[0]; + bucket += 2; + Elf64_Xword *chain = bucket + nbucket; + + /* New size of the section. */ + hashd->d_size = ((2 + symd->d_size / elsize + nbucket) + * sizeof (Elf64_Xword)); + update_section_size (hashd); + + /* Clear the arrays. */ + memset (bucket, '\0', + (symd->d_size / elsize + nbucket) + * sizeof (Elf64_Xword)); + + for (size_t inner = shdr_info[symtabidx].shdr.sh_info; + inner < symd->d_size / elsize; ++inner) + { + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symd, inner, &sym_mem); + assert (sym != NULL); + + const char *name = elf_strptr (elf, strshndx, + sym->st_name); + assert (name != NULL); + size_t hidx = elf_hash (name) % nbucket; + + if (bucket[hidx] == 0) + bucket[hidx] = inner; + else + { + hidx = bucket[hidx]; + + while (chain[hidx] != 0) + hidx = chain[hidx]; + + chain[hidx] = inner; + } + } + } + break; + + case SHT_GNU_versym: + /* If the symbol table changed we have to adjust the entries. */ + if (no_symtab_updates ()) + break; + + assert (shdr_info[cnt].idx > 0); + + /* The symbol version section in the new file. */ + scn = elf_getscn (newelf, shdr_info[cnt].idx); + + /* The symbol table data. */ + symd = elf_getdata (elf_getscn (newelf, shdr_info[symtabidx].idx), + NULL); + assert (symd != NULL); + + /* The version symbol data. */ + Elf_Data *verd = elf_getdata (scn, NULL); + assert (verd != NULL); + + /* The symbol version array. */ + GElf_Half *verstab = (GElf_Half *) verd->d_buf; + + /* Walk through the list and */ + size_t elsize = gelf_fsize (elf, verd->d_type, 1, + ehdr->e_version); + for (size_t inner = 1; inner < verd->d_size / elsize; ++inner) + if (newsymidx[inner] != 0) + /* Overwriting the same array works since the + reordering can only move entries to lower indices + in the array. */ + verstab[newsymidx[inner]] = verstab[inner]; + + /* New size of the section. */ + verd->d_size = gelf_fsize (newelf, verd->d_type, + symd->d_size + / gelf_fsize (elf, symd->d_type, 1, + ehdr->e_version), + ehdr->e_version); + update_section_size (verd); + break; + + case SHT_GROUP: + if (no_symtab_updates ()) + break; + + /* Yes, the symbol table changed. + Update the section header of the section group. */ + scn = elf_getscn (newelf, shdr_info[cnt].idx); + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + assert (shdr != NULL); + + shdr->sh_info = newsymidx[shdr->sh_info]; + + (void) gelf_update_shdr (scn, shdr); + break; + } + } + + /* Now that we have done all adjustments to the data, + we can actually write out the debug file. */ + if (debug_fname != NULL) + { + /* Finally write the file. */ + if (unlikely (elf_update (debugelf, ELF_C_WRITE) == -1)) + { + error (0, 0, gettext ("while writing '%s': %s"), + debug_fname, elf_errmsg (-1)); + result = 1; + goto fail_close; + } + + /* Create the real output file. First rename, then change the + mode. */ + if (rename (tmp_debug_fname, debug_fname) != 0 + || fchmod (debug_fd, mode) != 0) + { + error (0, errno, gettext ("while creating '%s'"), debug_fname); + result = 1; + goto fail_close; + } + + /* The temporary file does not exist anymore. */ + tmp_debug_fname = NULL; + + if (!remove_shdrs) + { + uint32_t debug_crc; + Elf_Data debug_crc_data = + { + .d_type = ELF_T_WORD, + .d_buf = &debug_crc, + .d_size = sizeof (debug_crc), + .d_version = EV_CURRENT + }; + + /* Compute the checksum which we will add to the executable. */ + if (crc32_file (debug_fd, &debug_crc) != 0) + { + error (0, errno, gettext ("\ +while computing checksum for debug information")); + unlink (debug_fname); + result = 1; + goto fail_close; + } + + /* Store it in the debuglink section data. */ + if (unlikely (gelf_xlatetof (newelf, &debuglink_crc_data, + &debug_crc_data, ehdr->e_ident[EI_DATA]) + != &debuglink_crc_data)) + INTERNAL_ERROR (fname); + } + } + + /* Finally finish the ELF header. Fill in the fields not handled by + libelf from the old file. */ + newehdr = gelf_getehdr (newelf, &newehdr_mem); + if (newehdr == NULL) + INTERNAL_ERROR (fname); + + memcpy (newehdr->e_ident, ehdr->e_ident, EI_NIDENT); + newehdr->e_type = ehdr->e_type; + newehdr->e_machine = ehdr->e_machine; + newehdr->e_version = ehdr->e_version; + newehdr->e_entry = ehdr->e_entry; + newehdr->e_flags = ehdr->e_flags; + newehdr->e_phoff = ehdr->e_phoff; + + /* 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) + & ~((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 + { + /* 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; + } + + if (gelf_update_ehdr (newelf, newehdr) == 0) + { + error (0, 0, gettext ("%s: error while creating ELF header: %s"), + fname, elf_errmsg (-1)); + return 1; + } + + /* We have everything from the old file. */ + if (elf_cntl (elf, ELF_C_FDDONE) != 0) + { + error (0, 0, gettext ("%s: error while reading the file: %s"), + fname, elf_errmsg (-1)); + return 1; + } + + /* 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) + | (permissive ? ELF_F_PERMISSIVE : 0)); + + /* Finally write the file. */ + if (elf_update (newelf, ELF_C_WRITE) == -1) + { + error (0, 0, gettext ("while writing '%s': %s"), + fname, elf_errmsg (-1)); + result = 1; + } + + if (remove_shdrs) + { + /* libelf can't cope without the section headers being properly intact. + So we just let it write them normally, and then we nuke them later. */ + + if (newehdr->e_ident[EI_CLASS] == ELFCLASS32) + { + assert (offsetof (Elf32_Ehdr, e_shentsize) + sizeof (Elf32_Half) + == offsetof (Elf32_Ehdr, e_shnum)); + assert (offsetof (Elf32_Ehdr, e_shnum) + sizeof (Elf32_Half) + == offsetof (Elf32_Ehdr, e_shstrndx)); + const Elf32_Off zero_off = 0; + const Elf32_Half zero[3] = { 0, 0, SHN_UNDEF }; + if (pwrite_retry (fd, &zero_off, sizeof zero_off, + offsetof (Elf32_Ehdr, e_shoff)) != sizeof zero_off + || (pwrite_retry (fd, zero, sizeof zero, + offsetof (Elf32_Ehdr, e_shentsize)) + != sizeof zero) + || ftruncate64 (fd, shdr_info[shdridx].shdr.sh_offset) < 0) + { + error (0, errno, gettext ("while writing '%s'"), + fname); + result = 1; + } + } + else + { + assert (offsetof (Elf64_Ehdr, e_shentsize) + sizeof (Elf64_Half) + == offsetof (Elf64_Ehdr, e_shnum)); + assert (offsetof (Elf64_Ehdr, e_shnum) + sizeof (Elf64_Half) + == offsetof (Elf64_Ehdr, e_shstrndx)); + const Elf64_Off zero_off = 0; + const Elf64_Half zero[3] = { 0, 0, SHN_UNDEF }; + if (pwrite_retry (fd, &zero_off, sizeof zero_off, + offsetof (Elf64_Ehdr, e_shoff)) != sizeof zero_off + || (pwrite_retry (fd, zero, sizeof zero, + offsetof (Elf64_Ehdr, e_shentsize)) + != sizeof zero) + || ftruncate64 (fd, shdr_info[shdridx].shdr.sh_offset) < 0) + { + error (0, errno, gettext ("while writing '%s'"), + fname); + result = 1; + } + } + } + + fail_close: + if (shdr_info != NULL) + { + /* For some sections we might have created an table to map symbol + table indices. */ + if (any_symtab_changes) + for (cnt = 1; cnt <= shdridx; ++cnt) + { + free (shdr_info[cnt].newsymidx); + if (shdr_info[cnt].debug_data != NULL) + free (shdr_info[cnt].debug_data->d_buf); + } + + /* Free the memory. */ + if ((shnum + 2) * sizeof (struct shdr_info) > MAX_STACK_ALLOC) + free (shdr_info); + } + + /* Free other resources. */ + if (shstrtab_data != NULL) + free (shstrtab_data->d_buf); + if (shst != NULL) + ebl_strtabfree (shst); + + /* That was it. Close the descriptors. */ + if (elf_end (newelf) != 0) + { + error (0, 0, gettext ("error while finishing '%s': %s"), fname, + elf_errmsg (-1)); + result = 1; + } + + if (debugelf != NULL && elf_end (debugelf) != 0) + { + error (0, 0, gettext ("error while finishing '%s': %s"), debug_fname, + elf_errmsg (-1)); + result = 1; + } + + fail: + /* Close the EBL backend. */ + if (ebl != NULL) + ebl_closebackend (ebl); + + /* Close debug file descriptor, if opened */ + if (debug_fd >= 0) + { + if (tmp_debug_fname != NULL) + unlink (tmp_debug_fname); + close (debug_fd); + } + + /* If requested, preserve the timestamp. */ + if (tvp != NULL) + { + if (futimes (fd, tvp) != 0) + { + error (0, errno, gettext ("\ +cannot set access and modification date of '%s'"), + output_fname ?: fname); + result = 1; + } + } + + /* Close the file descriptor if we created a new file. */ + if (output_fname != NULL) + close (fd); + + return result; +} + + +static int +handle_ar (int fd, Elf *elf, const char *prefix, const char *fname, + struct timeval tvp[2]) +{ + size_t prefix_len = prefix == NULL ? 0 : strlen (prefix); + size_t fname_len = strlen (fname) + 1; + char new_prefix[prefix_len + 1 + fname_len]; + char *cp = new_prefix; + + /* Create the full name of the file. */ + if (prefix != NULL) + { + cp = mempcpy (cp, prefix, prefix_len); + *cp++ = ':'; + } + memcpy (cp, fname, fname_len); + + + /* Process all the files contained in the archive. */ + Elf *subelf; + Elf_Cmd cmd = ELF_C_RDWR; + int result = 0; + while ((subelf = elf_begin (fd, cmd, elf)) != NULL) + { + /* The the header for this element. */ + Elf_Arhdr *arhdr = elf_getarhdr (subelf); + + if (elf_kind (subelf) == ELF_K_ELF) + result |= handle_elf (fd, subelf, new_prefix, arhdr->ar_name, 0, NULL); + else if (elf_kind (subelf) == ELF_K_AR) + result |= handle_ar (fd, subelf, new_prefix, arhdr->ar_name, NULL); + + /* Get next archive element. */ + cmd = elf_next (subelf); + if (unlikely (elf_end (subelf) != 0)) + INTERNAL_ERROR (fname); + } + + if (tvp != NULL) + { + if (unlikely (futimes (fd, tvp) != 0)) + { + error (0, errno, gettext ("\ +cannot set access and modification date of '%s'"), fname); + result = 1; + } + } + + if (unlikely (close (fd) != 0)) + error (EXIT_FAILURE, errno, gettext ("while closing '%s'"), fname); + + return result; +} + + +#include "debugpred.h" |