1 /* Align section.
2 Copyright (C) 2002, 2005 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 <inttypes.h>
35 #include <stdlib.h>
36 #include <sys/param.h>
37
38 #include <libasmP.h>
39 #include <system.h>
40
41
42 int
asm_align(AsmScn_t * asmscn,GElf_Word value)43 asm_align (AsmScn_t *asmscn, GElf_Word value)
44 {
45 if (asmscn == NULL)
46 /* An earlier error. */
47 return -1;
48
49 /* The alignment value must be a power of two. */
50 if (unlikely (! powerof2 (value)))
51 {
52 __libasm_seterrno (ASM_E_INVALID);
53 return -1;
54 }
55
56 if (unlikely (asmscn->ctx->textp))
57 {
58 fprintf (asmscn->ctx->out.file, "\t.align %" PRId32 ", ",
59 (int32_t) value);
60 if (asmscn->pattern->len == 1)
61 fprintf (asmscn->ctx->out.file, "%02hhx\n", asmscn->pattern->bytes[0]);
62 else
63 {
64 fputc_unlocked ('"', asmscn->ctx->out.file);
65
66 for (size_t cnt = 0; cnt < asmscn->pattern->len; ++cnt)
67 fprintf (asmscn->ctx->out.file, "\\x%02hhx",
68 asmscn->pattern->bytes[cnt]);
69
70 fputs_unlocked ("\"\n", asmscn->ctx->out.file);
71 }
72 return 0;
73 }
74
75 rwlock_wrlock (asmscn->ctx->lock);
76
77 int result = 0;
78
79 /* Fillbytes necessary? */
80 if ((asmscn->offset & (value - 1)) != 0)
81 {
82 /* Add fillbytes. */
83 size_t cnt = value - (asmscn->offset & (value - 1));
84
85 /* Ensure there is enough room to add the fill bytes. */
86 result = __libasm_ensure_section_space (asmscn, cnt);
87 if (result != 0)
88 goto out;
89
90 /* Fill in the bytes. We align the pattern according to the
91 current offset. */
92 size_t byteptr = asmscn->offset % asmscn->pattern->len;
93
94 /* Update the total size. */
95 asmscn->offset += cnt;
96
97 do
98 {
99 asmscn->content->data[asmscn->content->len++]
100 = asmscn->pattern->bytes[byteptr++];
101
102 if (byteptr == asmscn->pattern->len)
103 byteptr = 0;
104 }
105 while (--cnt > 0);
106 }
107
108 /* Remember the maximum alignment for this subsection. */
109 if (asmscn->max_align < value)
110 {
111 asmscn->max_align = value;
112
113 /* Update the parent as well (if it exists). */
114 if (asmscn->subsection_id != 0)
115 {
116 rwlock_wrlock (asmscn->data.up->ctx->lock);
117
118 if (asmscn->data.up->max_align < value)
119 asmscn->data.up->max_align = value;
120
121 rwlock_unlock (asmscn->data.up->ctx->lock);
122 }
123 }
124
125 out:
126 rwlock_unlock (asmscn->ctx->lock);
127
128 return result;
129 }
130
131
132 /* Ensure there are at least LEN bytes available in the output buffer
133 for ASMSCN. */
134 int
135 internal_function
__libasm_ensure_section_space(AsmScn_t * asmscn,size_t len)136 __libasm_ensure_section_space (AsmScn_t *asmscn, size_t len)
137 {
138 /* The blocks with the section content are kept in a circular
139 single-linked list. */
140 size_t size;
141
142 if (asmscn->content == NULL)
143 {
144 /* This is the first block. */
145 size = MAX (2 * len, 960);
146
147 asmscn->content = (struct AsmData *) malloc (sizeof (struct AsmData)
148 + size);
149 if (asmscn->content == NULL)
150 return -1;
151
152 asmscn->content->next = asmscn->content;
153 }
154 else
155 {
156 struct AsmData *newp;
157
158 if (asmscn->content->maxlen - asmscn->content->len >= len)
159 /* Nothing to do, there is enough space. */
160 return 0;
161
162 size = MAX (2 *len, MIN (32768, 2 * asmscn->offset));
163
164 newp = (struct AsmData *) malloc (sizeof (struct AsmData) + size);
165 if (newp == NULL)
166 return -1;
167
168 newp->next = asmscn->content->next;
169 asmscn->content = asmscn->content->next = newp;
170 }
171
172 asmscn->content->len = 0;
173 asmscn->content->maxlen = size;
174
175 return 0;
176 }
177