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
44 static AsmCtx_t *
prepare_text_output(AsmCtx_t * result)45 prepare_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
66 static AsmCtx_t *
prepare_binary_output(AsmCtx_t * result,Ebl * ebl)67 prepare_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
126 AsmCtx_t *
asm_begin(fname,ebl,textp)127 asm_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