blob: 6248786cc3261cf5800eef8a7d02a06c13df3cc2 [file] [log] [blame]
/* Create descriptor for assembling.
Copyright (C) 2002, 2016 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <>, 2002.
This file is free software; you can redistribute it and/or modify
it under the terms of either
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at
your option) any later version
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at
your option) any later version
or both in parallel, as here.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see <>. */
# include <config.h>
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <gelf.h>
#include "libasmP.h"
#include <system.h>
static AsmCtx_t *
prepare_text_output (AsmCtx_t *result)
if (result->fd == -1)
result->out.file = stdout;
result->out.file = fdopen (result->fd, "a");
if (result->out.file == NULL)
close (result->fd);
free (result);
result = NULL;
__fsetlocking (result->out.file, FSETLOCKING_BYCALLER);
return result;
static AsmCtx_t *
prepare_binary_output (AsmCtx_t *result, Ebl *ebl)
GElf_Ehdr *ehdr;
GElf_Ehdr ehdr_mem;
/* Create the ELF descriptor for the file. */
result->out.elf = elf_begin (result->fd, ELF_C_WRITE_MMAP, NULL);
if (result->out.elf == NULL)
unlink (result->tmp_fname);
close (result->fd);
free (result);
__libasm_seterrno (ASM_E_LIBELF);
return NULL;
/* Create the ELF header for the output file. */
int class = ebl_get_elfclass (ebl);
if (gelf_newehdr (result->out.elf, class) == 0)
goto err_libelf;
ehdr = gelf_getehdr (result->out.elf, &ehdr_mem);
/* If this failed we are in trouble. */
assert (ehdr != NULL);
/* We create an object file. */
ehdr->e_type = ET_REL;
/* Set the ELF version. */
ehdr->e_version = EV_CURRENT;
/* Use the machine, class, and endianess values from the Ebl descriptor. */
ehdr->e_machine = ebl_get_elfmachine (ebl);
ehdr->e_ident[EI_CLASS] = class;
ehdr->e_ident[EI_DATA] = ebl_get_elfdata (ebl);
memcpy (&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG);
/* Write the ELF header information back. */
(void) gelf_update_ehdr (result->out.elf, ehdr);
/* No section so far. */
result->section_list = NULL;
/* Initialize the hash table. */
asm_symbol_tab_init (&result->symbol_tab, 67);
result->nsymbol_tab = 0;
/* And the string tables. */
result->section_strtab = dwelf_strtab_init (true);
result->symbol_strtab = dwelf_strtab_init (true);
/* We have no section groups so far. */
result->groups = NULL;
result->ngroups = 0;
return result;
AsmCtx_t *
asm_begin (const char *fname, Ebl *ebl, bool textp)
if (fname == NULL && ! textp)
return NULL;
size_t fname_len = fname != NULL ? strlen (fname) : 0;
/* Create the file descriptor. We do not generate the output file
right away. Instead we create a temporary file in the same
directory which, if everything goes alright, will replace a
possibly existing file with the given name. */
AsmCtx_t *result
= (AsmCtx_t *) malloc (sizeof (AsmCtx_t) + 2 * fname_len + 9);
if (result == NULL)
return NULL;
/* Initialize the lock. */
rwlock_init (result->lock);
if (fname != NULL)
/* Create the name of the temporary file. */
result->fname = stpcpy (mempcpy (result->tmp_fname, fname, fname_len),
".XXXXXX") + 1;
memcpy (result->fname, fname, fname_len + 1);
/* Create the temporary file. */
result->fd = mkstemp (result->tmp_fname);
if (result->fd == -1)
int save_errno = errno;
free (result);
__libasm_seterrno (ASM_E_CANNOT_CREATE);
errno = save_errno;
return NULL;
result->fd = -1;
/* Initialize the counter for temporary symbols. */
result->tempsym_count = 0;
/* Now we differentiate between textual and binary output. */
result->textp = textp;
if (textp)
result = prepare_text_output (result);
result = prepare_binary_output (result, ebl);
return result;