xref: /illumos-gate/usr/src/lib/libdwarf/common/pro_reloc.c (revision 915894ef19890baaed00080f85f6b69e225cda98)
1 /*
2   Copyright (C) 2000,2004 Silicon Graphics, Inc.  All Rights Reserved.
3   Portions Copyright 2008-2016 David Anderson, Inc. All rights reserved.
4 
5   This program is free software; you can redistribute it and/or modify it
6   under the terms of version 2.1 of the GNU Lesser General Public License
7   as published by the Free Software Foundation.
8 
9   This program is distributed in the hope that it would be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12 
13   Further, this software is distributed without any warranty that it is
14   free of the rightful claim of any third person regarding infringement
15   or the like.  Any license provided herein, whether implied or
16   otherwise, applies only to this software file.  Patent licenses, if
17   any, provided herein do not apply to combinations of this program with
18   other software, or any other product whatsoever.
19 
20   You should have received a copy of the GNU Lesser General Public
21   License along with this program; if not, write the Free Software
22   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301,
23   USA.
24 
25 */
26 
27 #include "config.h"
28 #include "libdwarfdefs.h"
29 #include <stdio.h>
30 #ifdef HAVE_STRING_H
31 #include <string.h>
32 #endif /* HAVE_STRING_H */
33 #ifdef HAVE_STDDEF_H
34 #include <stddef.h>
35 #endif /* HAVE_STDDEF_H */
36 #include "pro_incl.h"
37 #include "dwarf.h"
38 #include "libdwarf.h"
39 #include "pro_opaque.h"
40 #include "pro_error.h"
41 #include "pro_alloc.h"
42 #include "pro_reloc.h"
43 
44 
45 /*  Do initial alloc of newslots slots.
46     Fails only if malloc fails.
47 
48     Supposed to be called before any relocs allocated.
49     Ignored if after any allocated.
50 
51     Part of an optimization, so that for a known 'newslots'
52     relocations count we can preallocate the right size block.
53     Called from just 2 places.
54 
55     We use 'slots' so we don't have to do a new
56     allocation for every relocation, just a new
57     allocation every n slots. slots_in_block.
58 
59     returns DW_DLV_OK or  DW_DLV_ERROR
60 */
61 int
62 _dwarf_pro_pre_alloc_specific_reloc_slots(Dwarf_P_Debug dbg,
63     Dwarf_P_Per_Reloc_Sect prel,
64     Dwarf_Unsigned newslots)
65 {
66     unsigned long len = 0;
67     struct Dwarf_P_Relocation_Block_s *data = 0;
68     unsigned long slots_in_blk = (unsigned long) newslots;
69     unsigned long rel_rec_size = dbg->de_relocation_record_size;
70 
71     if (prel->pr_first_block) {
72         return DW_DLV_OK;       /* do nothing */
73     }
74 
75     len = sizeof(struct Dwarf_P_Relocation_Block_s) +
76         slots_in_blk * rel_rec_size;
77     data = (struct Dwarf_P_Relocation_Block_s *)
78         _dwarf_p_get_alloc(dbg, len);
79     if (!data) {
80         return DW_DLV_ERROR;
81     }
82     data->rb_slots_in_block = slots_in_blk;     /* could use default
83         here, as fallback in case our origininal
84         estimate wrong. When we call this we
85         presumably know what we are doing, so
86         keep this count for now */
87     data->rb_next_slot_to_use = 0;
88     data->rb_where_to_add_next =
89         ((char *) data) + sizeof(struct Dwarf_P_Relocation_Block_s);
90     data->rb_data = data->rb_where_to_add_next;
91 
92     prel->pr_first_block = data;
93     prel->pr_last_block = data;
94     prel->pr_block_count = 1;
95     return DW_DLV_OK;
96 }
97 
98 
99 /*Do alloc of slots.
100   Fails only if malloc fails.
101 
102   Only allocator used.
103 
104   returns DW_DLV_OK or  DW_DLV_ERROR
105 */
106 int
107 _dwarf_pro_alloc_reloc_slots(Dwarf_P_Debug dbg, int rel_sec_index)
108 {
109     unsigned long len = 0;
110     struct Dwarf_P_Relocation_Block_s *data = 0;
111     Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[rel_sec_index];
112     unsigned long slots_in_blk = prel->pr_slots_per_block_to_alloc;
113     unsigned long rel_rec_size = dbg->de_relocation_record_size;
114 
115     len = sizeof(struct Dwarf_P_Relocation_Block_s) +
116         slots_in_blk * rel_rec_size;
117 
118     data = (struct Dwarf_P_Relocation_Block_s *)
119         _dwarf_p_get_alloc(dbg, len);
120     if (!data) {
121         return DW_DLV_ERROR;
122     }
123 
124     if (prel->pr_first_block) {
125         prel->pr_last_block->rb_next = data;
126         prel->pr_last_block = data;
127         prel->pr_block_count += 1;
128     } else {
129         prel->pr_first_block = data;
130         prel->pr_last_block = data;
131         prel->pr_block_count = 1;
132     }
133     data->rb_slots_in_block = slots_in_blk;
134     data->rb_next_slot_to_use = 0;
135     data->rb_where_to_add_next =
136         ((char *) data) + sizeof(struct Dwarf_P_Relocation_Block_s);
137     data->rb_data = data->rb_where_to_add_next;
138     return DW_DLV_OK;
139 
140 }
141 
142 /*  Reserve a slot. return DW_DLV_OK if succeeds.
143 
144     Return DW_DLV_ERROR if fails (malloc error).
145 
146     Use the relrec_to_fill to pass back a pointer to
147     a slot space to use.  */
148 int
149 _dwarf_pro_reloc_get_a_slot(Dwarf_P_Debug dbg,
150     int base_sec_index, void **relrec_to_fill)
151 {
152     struct Dwarf_P_Relocation_Block_s *data = 0;
153     Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[base_sec_index];
154     unsigned long rel_rec_size = dbg->de_relocation_record_size;
155 
156     char *ret_addr = 0;
157 
158     data = prel->pr_last_block;
159     if ((data == 0) ||
160         (data->rb_next_slot_to_use >= data->rb_slots_in_block)) {
161         int res;
162 
163         res = _dwarf_pro_alloc_reloc_slots(dbg, base_sec_index);
164         if (res != DW_DLV_OK) {
165             return res;
166         }
167     }
168 
169     data = prel->pr_last_block;
170     /* now we have an empty slot */
171     ret_addr = data->rb_where_to_add_next;
172     data->rb_where_to_add_next += rel_rec_size;
173     data->rb_next_slot_to_use += 1;
174     prel->pr_reloc_total_count += 1;
175     *relrec_to_fill = (void *) ret_addr;
176     return DW_DLV_OK;
177 
178 }
179 
180 /*
181     On success  returns count of
182     .rel.* sections that are symbolic
183     thru count_of_relocation_sections.
184 
185     On success, returns DW_DLV_OK.
186 
187     If this is not a 'symbolic' run, returns
188     DW_DLV_NO_ENTRY.
189 
190     No errors are possible.
191 */
192 /*ARGSUSED*/
193 int
194 dwarf_get_relocation_info_count(Dwarf_P_Debug dbg,
195     Dwarf_Unsigned *
196     count_of_relocation_sections,
197     int *drd_buffer_version,
198     UNUSEDARG Dwarf_Error * error)
199 {
200     if (dbg->de_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
201         int i = 0;
202         unsigned int count = 0;
203 
204         for (i = 0; i < NUM_DEBUG_SECTIONS; ++i) {
205             if (dbg->de_reloc_sect[i].pr_reloc_total_count > 0) {
206                 ++count;
207             }
208         }
209         *count_of_relocation_sections = (Dwarf_Unsigned) count;
210         *drd_buffer_version = DWARF_DRD_BUFFER_VERSION;
211         return DW_DLV_OK;
212     }
213     /*  Reset to start at beginning of reloc groups. */
214     dbg->de_reloc_next_to_return = 0;
215     return DW_DLV_NO_ENTRY;
216 }
217 
218 int
219 dwarf_get_relocation_info(Dwarf_P_Debug dbg,
220     Dwarf_Signed * elf_section_index,
221     Dwarf_Signed * elf_section_index_link,
222     Dwarf_Unsigned * relocation_buffer_count,
223     Dwarf_Relocation_Data * reldata_buffer,
224     Dwarf_Error * error)
225 {
226     int next = dbg->de_reloc_next_to_return;
227 
228     if (dbg->de_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
229         int i = 0;
230 
231         for (i = next; i < NUM_DEBUG_SECTIONS; ++i) {
232             /*  de_reloc_sect[] and de_elf_sects[] are
233                 in direct parallel. */
234             Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[i];
235             int elf_sect_num =  dbg->de_elf_sects[i];
236 
237             if (prel->pr_reloc_total_count > 0) {
238                 /*  Set up 'next' for subsequent call to
239                     dwarf_get_relocation_info(). */
240                 dbg->de_reloc_next_to_return = i + 1;
241 
242                 /* ASSERT: prel->pr_block_count == 1 */
243                 *elf_section_index = prel->pr_sect_num_of_reloc_sect;
244 
245                 /*  Elf sec num in generated elf */
246                 *elf_section_index_link = elf_sect_num;
247 
248                 *relocation_buffer_count = prel->pr_reloc_total_count;
249                 *reldata_buffer = (Dwarf_Relocation_Data)
250                     (prel->pr_first_block->rb_data);
251                 return DW_DLV_OK;
252             }
253         }
254         DWARF_P_DBG_ERROR(dbg, DW_DLE_REL_ALLOC, DW_DLV_ERROR);
255     }
256     return DW_DLV_NO_ENTRY;
257 }
258