1/* Create descriptor for assembling.
2   Copyright (C) 2002 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2002.
5
6   Red Hat elfutils is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by the
8   Free Software Foundation; version 2 of the License.
9
10   Red Hat elfutils is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   General Public License for more details.
14
15   You should have received a copy of the GNU General Public License along
16   with Red Hat elfutils; if not, write to the Free Software Foundation,
17   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19   Red Hat elfutils is an included package of the Open Invention Network.
20   An included package of the Open Invention Network is a package for which
21   Open Invention Network licensees cross-license their patents.  No patent
22   license is granted, either expressly or impliedly, by designation as an
23   included package.  Should you wish to participate in the Open Invention
24   Network licensing program, please visit www.openinventionnetwork.com
25   <http://www.openinventionnetwork.com>.  */
26
27#ifdef HAVE_CONFIG_H
28# include <config.h>
29#endif
30
31#include <assert.h>
32#include <errno.h>
33#include <stdio.h>
34#include <stdio_ext.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38
39#include <gelf.h>
40#include "libasmP.h"
41#include <system.h>
42
43
44static AsmCtx_t *
45prepare_text_output (AsmCtx_t *result)
46{
47  if (result->fd == -1)
48    result->out.file = stdout;
49  else
50    {
51      result->out.file = fdopen (result->fd, "a");
52      if (result->out.file == NULL)
53	{
54	  close (result->fd);
55	  free (result);
56	  result = NULL;
57	}
58
59      __fsetlocking (result->out.file, FSETLOCKING_BYCALLER);
60    }
61
62  return result;
63}
64
65
66static AsmCtx_t *
67prepare_binary_output (AsmCtx_t *result, Ebl *ebl)
68{
69  GElf_Ehdr *ehdr;
70  GElf_Ehdr ehdr_mem;
71
72  /* Create the ELF descriptor for the file.  */
73  result->out.elf = elf_begin (result->fd, ELF_C_WRITE_MMAP, NULL);
74  if (result->out.elf == NULL)
75    {
76    err_libelf:
77      unlink (result->tmp_fname);
78      close (result->fd);
79      free (result);
80      __libasm_seterrno (ASM_E_LIBELF);
81      return NULL;
82    }
83
84  /* Create the ELF header for the output file.  */
85  int class = ebl_get_elfclass (ebl);
86  if (gelf_newehdr (result->out.elf, class) == 0)
87    goto err_libelf;
88
89  ehdr = gelf_getehdr (result->out.elf, &ehdr_mem);
90  /* If this failed we are in trouble.  */
91  assert (ehdr != NULL);
92
93  /* We create an object file.  */
94  ehdr->e_type = ET_REL;
95  /* Set the ELF version.  */
96  ehdr->e_version = EV_CURRENT;
97
98  /* Use the machine, class, and endianess values from the Ebl descriptor.  */
99  ehdr->e_machine = ebl_get_elfmachine (ebl);
100  ehdr->e_ident[EI_CLASS] = class;
101  ehdr->e_ident[EI_DATA] = ebl_get_elfdata (ebl);
102
103  memcpy (&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG);
104
105  /* Write the ELF header information back.  */
106  (void) gelf_update_ehdr (result->out.elf, ehdr);
107
108  /* No section so far.  */
109  result->section_list = NULL;
110
111  /* Initialize the hash table.  */
112  asm_symbol_tab_init (&result->symbol_tab, 67);
113  result->nsymbol_tab = 0;
114  /* And the string tables.  */
115  result->section_strtab = ebl_strtabinit (true);
116  result->symbol_strtab = ebl_strtabinit (true);
117
118  /* We have no section groups so far.  */
119  result->groups = NULL;
120  result->ngroups = 0;
121
122  return result;
123}
124
125
126AsmCtx_t *
127asm_begin (fname, ebl, textp)
128     const char *fname;
129     Ebl *ebl;
130     bool textp;
131{
132  if (fname == NULL && ! textp)
133    return NULL;
134
135  size_t fname_len = fname != NULL ? strlen (fname) : 0;
136
137  /* Create the file descriptor.  We do not generate the output file
138     right away.  Instead we create a temporary file in the same
139     directory which, if everything goes alright, will replace a
140     possibly existing file with the given name.  */
141  AsmCtx_t *result
142    = (AsmCtx_t *) malloc (sizeof (AsmCtx_t) + 2 * fname_len + 9);
143  if (result == NULL)
144    return NULL;
145
146      /* Initialize the lock.  */
147      rwlock_init (result->lock);
148
149  if (fname != NULL)
150    {
151      /* Create the name of the temporary file.  */
152      result->fname = stpcpy (mempcpy (result->tmp_fname, fname, fname_len),
153			      ".XXXXXX") + 1;
154      memcpy (result->fname, fname, fname_len + 1);
155
156      /* Create the temporary file.  */
157      result->fd = mkstemp (result->tmp_fname);
158      if (result->fd == -1)
159	{
160	  int save_errno = errno;
161	  free (result);
162	  __libasm_seterrno (ASM_E_CANNOT_CREATE);
163	  errno = save_errno;
164	  return NULL;
165	}
166    }
167  else
168    result->fd = -1;
169
170  /* Initialize the counter for temporary symbols.  */
171  result->tempsym_count = 0;
172
173  /* Now we differentiate between textual and binary output.   */
174  result->textp = textp;
175  if (textp)
176    result = prepare_text_output (result);
177  else
178    result = prepare_binary_output (result, ebl);
179
180  return result;
181}
182