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Diffstat (limited to 'src/src/arlib.c')
| -rw-r--r-- | src/src/arlib.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/src/src/arlib.c b/src/src/arlib.c new file mode 100644 index 00000000..bcf9344b --- /dev/null +++ b/src/src/arlib.c @@ -0,0 +1,280 @@ +/* Functions to handle creation of Linux archives. + Copyright (C) 2007-2012 Red Hat, Inc. + Written by Ulrich Drepper <drepper@redhat.com>, 2007. + + 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 <assert.h> +#include <error.h> +#include <gelf.h> +#include <libintl.h> +#include <stdio.h> +#include <stdlib.h> +#include <time.h> + +#include <system.h> + +#include "arlib.h" + + +/* The one symbol table we hanble. */ +struct arlib_symtab symtab; + + +/* Initialize ARLIB_SYMTAB structure. */ +void +arlib_init (void) +{ +#define obstack_chunk_alloc xmalloc +#define obstack_chunk_free free + obstack_init (&symtab.symsoffob); + obstack_init (&symtab.symsnameob); + obstack_init (&symtab.longnamesob); + + /* We add the archive header here as well, that avoids allocating + another memory block. */ + struct ar_hdr ar_hdr; + memcpy (ar_hdr.ar_name, "/ ", sizeof (ar_hdr.ar_name)); + /* Using snprintf here has a problem: the call always wants to add a + NUL byte. We could use a trick whereby we specify the target + buffer size longer than it is and this would not actually fail, + since all the fields are consecutive and we fill them in + sequence (i.e., the NUL byte gets overwritten). But + _FORTIFY_SOURCE=2 would not let us play these games. Therefore + we play it safe. */ + char tmpbuf[sizeof (ar_hdr.ar_date) + 1]; + memcpy (ar_hdr.ar_date, tmpbuf, + snprintf (tmpbuf, sizeof (tmpbuf), "%-*lld", + (int) sizeof (ar_hdr.ar_date), + (arlib_deterministic_output ? 0 + : (long long int) time (NULL)))); + assert ((sizeof (struct ar_hdr) % sizeof (uint32_t)) == 0); + + /* Note the string for the ar_uid and ar_gid cases is longer than + necessary. This does not matter since we copy only as much as + necessary but it helps the compiler to use the same string for + the ar_mode case. */ + memcpy (ar_hdr.ar_uid, "0 ", sizeof (ar_hdr.ar_uid)); + memcpy (ar_hdr.ar_gid, "0 ", sizeof (ar_hdr.ar_gid)); + memcpy (ar_hdr.ar_mode, "0 ", sizeof (ar_hdr.ar_mode)); + memcpy (ar_hdr.ar_fmag, ARFMAG, sizeof (ar_hdr.ar_fmag)); + + /* Add the archive header to the file content. */ + obstack_grow (&symtab.symsoffob, &ar_hdr, sizeof (ar_hdr)); + + /* The first word in the offset table specifies the size. Create + such an entry now. The real value will be filled-in later. For + all supported platforms the following is true. */ + assert (sizeof (uint32_t) == sizeof (int)); + obstack_int_grow (&symtab.symsoffob, 0); + + /* The long name obstack also gets its archive header. As above, + some of the input strings are longer than required but we only + copy the necessary part. */ + memcpy (ar_hdr.ar_name, "// ", sizeof (ar_hdr.ar_name)); + memcpy (ar_hdr.ar_date, " ", sizeof (ar_hdr.ar_date)); + memcpy (ar_hdr.ar_uid, " ", sizeof (ar_hdr.ar_uid)); + memcpy (ar_hdr.ar_gid, " ", sizeof (ar_hdr.ar_gid)); + memcpy (ar_hdr.ar_mode, " ", sizeof (ar_hdr.ar_mode)); + /* The ar_size field will be filled in later and ar_fmag is already OK. */ + obstack_grow (&symtab.longnamesob, &ar_hdr, sizeof (ar_hdr)); + + /* All other members are zero. */ + symtab.symsofflen = 0; + symtab.symsoff = NULL; + symtab.symsnamelen = 0; + symtab.symsname = NULL; +} + + +/* Finalize ARLIB_SYMTAB content. */ +void +arlib_finalize (void) +{ + char tmpbuf[sizeof (((struct ar_hdr *) NULL)->ar_size) + 1]; + + symtab.longnameslen = obstack_object_size (&symtab.longnamesob); + if (symtab.longnameslen != sizeof (struct ar_hdr)) + { + if ((symtab.longnameslen & 1) != 0) + { + /* Add one more byte to make length even. */ + obstack_grow (&symtab.longnamesob, "\n", 1); + ++symtab.longnameslen; + } + + symtab.longnames = obstack_finish (&symtab.longnamesob); + + memcpy (&((struct ar_hdr *) symtab.longnames)->ar_size, tmpbuf, + snprintf (tmpbuf, sizeof (tmpbuf), "%-*zu", + (int) sizeof (((struct ar_hdr *) NULL)->ar_size), + symtab.longnameslen - sizeof (struct ar_hdr))); + } + + symtab.symsofflen = obstack_object_size (&symtab.symsoffob); + assert (symtab.symsofflen % sizeof (uint32_t) == 0); + if (symtab.symsofflen != 0) + { + symtab.symsoff = (uint32_t *) obstack_finish (&symtab.symsoffob); + + /* Fill in the number of offsets now. */ + symtab.symsoff[AR_HDR_WORDS] = le_bswap_32 ((symtab.symsofflen + - sizeof (struct ar_hdr)) + / sizeof (uint32_t) - 1); + } + + symtab.symsnamelen = obstack_object_size (&symtab.symsnameob); + if ((symtab.symsnamelen & 1) != 0) + { + /* Add one more NUL byte to make length even. */ + obstack_grow (&symtab.symsnameob, "", 1); + ++symtab.symsnamelen; + } + symtab.symsname = obstack_finish (&symtab.symsnameob); + + /* Determine correction for the offsets in the symbol table. */ + off_t disp = 0; + if (symtab.symsnamelen > 0) + disp = symtab.symsofflen + symtab.symsnamelen; + if (symtab.longnameslen > sizeof (struct ar_hdr)) + disp += symtab.longnameslen; + + if (disp != 0 && symtab.symsoff != NULL) + { + uint32_t nsyms = le_bswap_32 (symtab.symsoff[AR_HDR_WORDS]); + + for (uint32_t cnt = 1; cnt <= nsyms; ++cnt) + { + uint32_t val = le_bswap_32 (symtab.symsoff[AR_HDR_WORDS + cnt]); + val += disp; + symtab.symsoff[AR_HDR_WORDS + cnt] = le_bswap_32 (val); + } + } + + /* See comment for ar_date above. */ + memcpy (&((struct ar_hdr *) symtab.symsoff)->ar_size, tmpbuf, + snprintf (tmpbuf, sizeof (tmpbuf), "%-*zu", + (int) sizeof (((struct ar_hdr *) NULL)->ar_size), + symtab.symsofflen + symtab.symsnamelen + - sizeof (struct ar_hdr))); +} + + +/* Free resources for ARLIB_SYMTAB. */ +void +arlib_fini (void) +{ + obstack_free (&symtab.symsoffob, NULL); + obstack_free (&symtab.symsnameob, NULL); + obstack_free (&symtab.longnamesob, NULL); +} + + +/* Add name a file offset of a symbol. */ +void +arlib_add_symref (const char *symname, off_t symoff) +{ + /* For all supported platforms the following is true. */ + assert (sizeof (uint32_t) == sizeof (int)); + obstack_int_grow (&symtab.symsoffob, (int) le_bswap_32 (symoff)); + + size_t symname_len = strlen (symname) + 1; + obstack_grow (&symtab.symsnameob, symname, symname_len); +} + + +/* Add symbols from ELF with value OFFSET to the symbol table SYMTAB. */ +void +arlib_add_symbols (Elf *elf, const char *arfname, const char *membername, + off_t off) +{ + if (sizeof (off) > sizeof (uint32_t) && off > ~((uint32_t) 0)) + /* The archive is too big. */ + error (EXIT_FAILURE, 0, gettext ("the archive '%s' is too large"), + arfname); + + /* We only add symbol tables for ELF files. It makes not much sense + to add symbols from executables but we do so for compatibility. + For DSOs and executables we use the dynamic symbol table, for + relocatable files all the DT_SYMTAB tables. */ + if (elf_kind (elf) != ELF_K_ELF) + return; + + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); + if (ehdr == NULL) + error (EXIT_FAILURE, 0, gettext ("cannot read ELF header of %s(%s): %s"), + arfname, membername, elf_errmsg (-1)); + + GElf_Word symtype; + if (ehdr->e_type == ET_REL) + symtype = SHT_SYMTAB; + else if (ehdr->e_type == ET_EXEC || ehdr->e_type == ET_DYN) + symtype = SHT_DYNSYM; + else + /* We do not handle that type. */ + return; + + /* Iterate over all sections. */ + Elf_Scn *scn = NULL; + while ((scn = elf_nextscn (elf, scn)) != NULL) + { + /* Get the section header. */ + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + continue; + + if (shdr->sh_type != symtype) + continue; + + Elf_Data *data = elf_getdata (scn, NULL); + if (data == NULL) + continue; + + int nsyms = shdr->sh_size / shdr->sh_entsize; + for (int ndx = shdr->sh_info; ndx < nsyms; ++ndx) + { + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (data, ndx, &sym_mem); + if (sym == NULL) + continue; + + /* Ignore undefined symbols. */ + if (sym->st_shndx == SHN_UNDEF) + continue; + + /* Use this symbol. */ + const char *symname = elf_strptr (elf, shdr->sh_link, sym->st_name); + if (symname != NULL) + arlib_add_symref (symname, off); + } + + /* Only relocatable files can have more than one symbol table. */ + if (ehdr->e_type != ET_REL) + break; + } +} |