Line data Source code
1 : /* Create descriptor for assembling.
2 : Copyright (C) 2002, 2016 Red Hat, Inc.
3 : This file is part of elfutils.
4 : Written by Ulrich Drepper <drepper@redhat.com>, 2002.
5 :
6 : This file is free software; you can redistribute it and/or modify
7 : it under the terms of either
8 :
9 : * the GNU Lesser General Public License as published by the Free
10 : Software Foundation; either version 3 of the License, or (at
11 : your option) any later version
12 :
13 : or
14 :
15 : * the GNU General Public License as published by the Free
16 : Software Foundation; either version 2 of the License, or (at
17 : your option) any later version
18 :
19 : or both in parallel, as here.
20 :
21 : elfutils is distributed in the hope that it will be useful, but
22 : WITHOUT ANY WARRANTY; without even the implied warranty of
23 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 : General Public License for more details.
25 :
26 : You should have received copies of the GNU General Public License and
27 : the GNU Lesser General Public License along with this program. If
28 : not, see <http://www.gnu.org/licenses/>. */
29 :
30 : #ifdef HAVE_CONFIG_H
31 : # include <config.h>
32 : #endif
33 :
34 : #include <assert.h>
35 : #include <errno.h>
36 : #include <stdio.h>
37 : #include <stdio_ext.h>
38 : #include <stdlib.h>
39 : #include <string.h>
40 : #include <unistd.h>
41 :
42 : #include <gelf.h>
43 : #include "libasmP.h"
44 : #include <system.h>
45 :
46 :
47 : static AsmCtx_t *
48 0 : prepare_text_output (AsmCtx_t *result)
49 : {
50 0 : if (result->fd == -1)
51 0 : result->out.file = stdout;
52 : else
53 : {
54 0 : result->out.file = fdopen (result->fd, "a");
55 0 : if (result->out.file == NULL)
56 : {
57 0 : close (result->fd);
58 0 : free (result);
59 0 : result = NULL;
60 : }
61 : else
62 0 : __fsetlocking (result->out.file, FSETLOCKING_BYCALLER);
63 : }
64 :
65 0 : return result;
66 : }
67 :
68 :
69 : static AsmCtx_t *
70 9 : prepare_binary_output (AsmCtx_t *result, Ebl *ebl)
71 : {
72 : GElf_Ehdr *ehdr;
73 : GElf_Ehdr ehdr_mem;
74 :
75 : /* Create the ELF descriptor for the file. */
76 9 : result->out.elf = elf_begin (result->fd, ELF_C_WRITE_MMAP, NULL);
77 9 : if (result->out.elf == NULL)
78 : {
79 0 : err_libelf:
80 0 : unlink (result->tmp_fname);
81 0 : close (result->fd);
82 0 : free (result);
83 0 : __libasm_seterrno (ASM_E_LIBELF);
84 0 : return NULL;
85 : }
86 :
87 : /* Create the ELF header for the output file. */
88 9 : int class = ebl_get_elfclass (ebl);
89 9 : if (gelf_newehdr (result->out.elf, class) == 0)
90 : goto err_libelf;
91 :
92 9 : ehdr = gelf_getehdr (result->out.elf, &ehdr_mem);
93 : /* If this failed we are in trouble. */
94 9 : assert (ehdr != NULL);
95 :
96 : /* We create an object file. */
97 9 : ehdr->e_type = ET_REL;
98 : /* Set the ELF version. */
99 9 : ehdr->e_version = EV_CURRENT;
100 :
101 : /* Use the machine, class, and endianess values from the Ebl descriptor. */
102 9 : ehdr->e_machine = ebl_get_elfmachine (ebl);
103 9 : ehdr->e_ident[EI_CLASS] = class;
104 9 : ehdr->e_ident[EI_DATA] = ebl_get_elfdata (ebl);
105 :
106 18 : memcpy (&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG);
107 :
108 : /* Write the ELF header information back. */
109 9 : (void) gelf_update_ehdr (result->out.elf, ehdr);
110 :
111 : /* No section so far. */
112 9 : result->section_list = NULL;
113 :
114 : /* Initialize the hash table. */
115 9 : asm_symbol_tab_init (&result->symbol_tab, 67);
116 9 : result->nsymbol_tab = 0;
117 : /* And the string tables. */
118 9 : result->section_strtab = dwelf_strtab_init (true);
119 9 : result->symbol_strtab = dwelf_strtab_init (true);
120 :
121 : /* We have no section groups so far. */
122 9 : result->groups = NULL;
123 9 : result->ngroups = 0;
124 :
125 9 : return result;
126 : }
127 :
128 :
129 : AsmCtx_t *
130 9 : asm_begin (const char *fname, Ebl *ebl, bool textp)
131 : {
132 9 : if (fname == NULL && ! textp)
133 : return NULL;
134 :
135 9 : 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 9 : AsmCtx_t *result
142 9 : = (AsmCtx_t *) malloc (sizeof (AsmCtx_t) + 2 * fname_len + 9);
143 9 : if (result == NULL)
144 : return NULL;
145 :
146 : /* Initialize the lock. */
147 : rwlock_init (result->lock);
148 :
149 9 : if (fname != NULL)
150 : {
151 : /* Create the name of the temporary file. */
152 36 : result->fname = stpcpy (mempcpy (result->tmp_fname, fname, fname_len),
153 9 : ".XXXXXX") + 1;
154 18 : memcpy (result->fname, fname, fname_len + 1);
155 :
156 : /* Create the temporary file. */
157 9 : result->fd = mkstemp (result->tmp_fname);
158 9 : if (result->fd == -1)
159 : {
160 0 : int save_errno = errno;
161 0 : free (result);
162 0 : __libasm_seterrno (ASM_E_CANNOT_CREATE);
163 0 : errno = save_errno;
164 0 : return NULL;
165 : }
166 : }
167 : else
168 0 : result->fd = -1;
169 :
170 : /* Initialize the counter for temporary symbols. */
171 9 : result->tempsym_count = 0;
172 :
173 : /* Now we differentiate between textual and binary output. */
174 9 : result->textp = textp;
175 9 : if (textp)
176 0 : result = prepare_text_output (result);
177 : else
178 9 : result = prepare_binary_output (result, ebl);
179 :
180 : return result;
181 : }
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