1 .\" Copyright (c) 2011 Kai Wang
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25 .\" $Id: dwarf_get_relocation_info.3 3644 2018-10-15 19:55:01Z jkoshy $
28 .Dt DWARF_GET_RELOCATION_INFO 3
31 .Nm dwarf_get_relocation_info
32 .Nd retrieve generated relocation arrays
38 .Fo dwarf_get_relocation_info
39 .Fa "Dwarf_P_Debug dbg"
40 .Fa "Dwarf_Signed *elf_section_index"
41 .Fa "Dwarf_Signed *elf_section_link"
42 .Fa "Dwarf_Unsigned *reloc_entry_count"
43 .Fa "Dwarf_Relocation_Data *reloc_buf"
44 .Fa "Dwarf_Error *err"
48 .Fn dwarf_get_relocation_info
49 is used to retrieve the relocation arrays generated by a prior call to
50 .Xr dwarf_transform_to_disk_form 3 .
52 Each call to this function retrieves the next available relocation
54 Application code should call this function repeatly to retrieve all
55 the relocation arrays.
56 The total number of generated relocation arrays retrievable
57 by this function may be obtained by calling function
58 .Xr dwarf_get_relocation_info_count 3 .
62 should reference a DWARF producer instance allocated using
63 .Xr dwarf_producer_init 3 in sequence.
65 .Xr dwarf_producer_init_b 3 .
67 .Dv DW_DLC_SYMBOLIC_RELOCATIONS
68 flag should have been set on the DWARF producer instance.
72 should point to a location which will be set to the ELF section index
73 of the relocation section to which the retrieved relocation array
78 should point to a location which will be set to the section index of
79 the ELF section to which the retrieved relocation array applies.
83 should point to a location which will be set to the total number of
84 relocation entries contained in the relocation array.
88 should point to a location which will be set to a pointer to the
89 retrieved array of relocation entries.
93 is not NULL, it will be used to store error information in case
96 The retrieved relocation entries are described using structure
97 .Vt Dwarf_Relocation_Data_s ,
98 defined in the header file
100 .Bd -literal -offset indent
101 typedef struct Dwarf_Relocation_Data_s {
102 unsigned char drd_type;
103 unsigned char drd_length;
104 Dwarf_Unsigned drd_offset;
105 Dwarf_Unsigned drd_symbol_index;
106 } *Dwarf_Relocation_Data;
110 .Vt Dwarf_Relocation_Data_s
111 consists of following fields:
112 .Bl -tag -width ".Va drd_symbol_index" -compact -offset indent
114 The type code of the relocation entry.
117 enumeration defined in the header file
119 specifies legal values for this field.
121 The size in bytes of the field to be relocated.
123 The section-relative offset of the field to be relocated.
124 .It Va drd_symbol_index
125 The symbol index associated with the relocation entry.
127 .Ss Memory Management
128 The memory area used for the relocation arrays is managed by the
131 .Fn dwarf_producer_finish
132 may be used to release it, along with other resources associated
133 with the producer instance.
136 .Fn dwarf_get_relocation_info
141 if there were no more relocation arrays to retrieve, or if the flag
142 .Dv DW_DLC_SYMBOLIC_RELOCATIONS
143 was not set on the producer instance.
144 In case of an error, function
145 .Fn dwarf_get_relocation_info
148 and sets the argument
151 To generate relocation entries and retrieve them, use:
152 .Bd -literal -offset indent
154 Dwarf_Relocation_Data buf;
155 Dwarf_Signed count, index, link;
156 Dwarf_Unsigned reloc_cnt, entry_cnt;
161 * Assume that dbg refers to a DWARF producer instance created
162 * created with DW_DLC_SYMBOLIC_RELOCATIONS flag set and that
163 * application code has added DWARF debugging information
164 * to the producer instance.
166 if ((count = dwarf_transform_to_disk_form(dbg, &de)) ==
168 warnx("dwarf_transform_to_disk_form failed: %s",
173 /* ... process generated section byte streams ... */
174 if (dwarf_get_relocation_info_count(dbg, &reloc_cnt, &version, &de) !=
176 warnx("dwarf_get_relocation_info_count failed: %s",
181 for (i = 0; (Dwarf_Unsigned) i < reloc_cnt; i++) {
182 if (dwarf_get_relocation_info(dbg, &index, &link, &entry_cnt,
183 &buf, &de) != DW_DLV_OK) {
184 warnx("dwarf_get_relocation_info failed: %s",
188 for (j = 0; (Dwarf_Unsigned) j < entry_cnt; j++) {
189 /* ...use each reloc data in buf[j]... */
193 dwarf_producer_finish(dbg, &de);
197 .Fn dwarf_get_relocation_info
199 .Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY"
200 .It Bq Er DW_DLE_ARGUMENT
203 .Ar elf_section_index ,
204 .Ar elf_section_link ,
205 .Ar reloc_entry_count
209 .It Bq Er DW_DLE_NO_ENTRY
210 There were no more ELF relocation arrays to retrieve.
211 .It Bq Er DW_DLE_NO_ENTRY
213 .Dv DW_DLC_SYMBOLIC_RELOCATIONS
214 was not set on the producer instance.
215 .It Bq Er DW_DLE_NO_ENTRY
217 .Xr dwarf_transform_to_disk_form 3
218 was not called prior to calling function
219 .Fn dwarf_get_relocation_info .
223 .Xr dwarf_get_relocation_info_count 3 ,
224 .Xr dwarf_producer_finish 3 ,
225 .Xr dwarf_producer_init 3 ,
226 .Xr dwarf_producer_init_b 3 ,
227 .Xr dwarf_reset_section_bytes 3 ,
228 .Xr dwarf_transform_to_disk_form 3