1 /* simple-object-common.h -- common structs for object file manipulation.
2    Copyright (C) 2010-2018 Free Software Foundation, Inc.
3 
4 This file is part of the libiberty library.
5 Libiberty is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9 
10 Libiberty is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 Library General Public License for more details.
14 
15 You should have received a copy of the GNU Library General Public
16 License along with libiberty; see the file COPYING.LIB.  If not,
17 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
18 Boston, MA 02110-1301, USA.  */
19 
20 /* Forward reference.  */
21 struct simple_object_functions;
22 
23 /* An object file opened for reading.  */
24 
25 struct simple_object_read_struct
26 {
27   /* The file descriptor.  */
28   int descriptor;
29   /* The offset within the file.  */
30   off_t offset;
31   /* The functions which do the actual work.  */
32   const struct simple_object_functions *functions;
33   /* Private data for the object file format.  */
34   void *data;
35 };
36 
37 /* Object file attributes.  */
38 
39 struct simple_object_attributes_struct
40 {
41   /* The functions which do the actual work.  */
42   const struct simple_object_functions *functions;
43   /* Private data for the object file format.  */
44   void *data;
45 };
46 
47 /* An object file being created.  */
48 
49 struct simple_object_write_struct
50 {
51   /* The functions which do the actual work.  */
52   const struct simple_object_functions *functions;
53   /* The segment_name argument from the user.  */
54   char *segment_name;
55   /* The start of the list of sections.  */
56   simple_object_write_section *sections;
57   /* The last entry in the list of sections.  */
58   simple_object_write_section *last_section;
59   /* Private data for the object file format.  */
60   void *data;
61 };
62 
63 /* A section in an object file being created.  */
64 
65 struct simple_object_write_section_struct
66 {
67   /* Next in the list of sections attached to an
68      simple_object_write.  */
69   simple_object_write_section *next;
70   /* The name of this section.  */
71   char *name;
72   /* The required alignment.  */
73   unsigned int align;
74   /* The first data attached to this section.  */
75   struct simple_object_write_section_buffer *buffers;
76   /* The last data attached to this section.  */
77   struct simple_object_write_section_buffer *last_buffer;
78 };
79 
80 /* Data attached to a section.  */
81 
82 struct simple_object_write_section_buffer
83 {
84   /* The next data for this section.  */
85   struct simple_object_write_section_buffer *next;
86   /* The size of the buffer.  */
87   size_t size;
88   /* The actual bytes.  */
89   const void *buffer;
90   /* A buffer to free, or NULL.  */
91   void *free_buffer;
92 };
93 
94 /* The number of bytes we read from the start of the file to pass to
95    the match function.  */
96 #define SIMPLE_OBJECT_MATCH_HEADER_LEN (16)
97 
98 /* Format-specific object file functions.  */
99 
100 struct simple_object_functions
101 {
102   /* If this file matches these functions, return a new value for the
103      private data for an simple_object_read.  HEADER is the first 16
104      bytes of the file.  DESCRIPTOR, OFFSET, SEGMENT_NAME, ERRMSG, and
105      ERR are as for simple_object_open_read.  If this file does not
106      match, this function should return NULL with *ERRMSG set to
107      NULL.  */
108   void *(*match) (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN],
109 		  int descriptor, off_t offset, const char *segment_name,
110 		  const char **errmsg, int *err);
111 
112   /* Implement simple_object_find_sections.  */
113   const char *(*find_sections) (simple_object_read *,
114 				int (*pfn) (void *, const char *,
115 					    off_t offset, off_t length),
116 				void *data,
117 				int *err);
118 
119   /* Return the private data for the attributes for SOBJ.  */
120   void *(*fetch_attributes) (simple_object_read *sobj, const char **errmsg,
121 			     int *err);
122 
123   /* Release the private data for an simple_object_read.  */
124   void (*release_read) (void *);
125 
126   /* Merge the private data for the attributes of two files.  If they
127      could be linked together, return NULL.  Otherwise return an error
128      message.  */
129   const char *(*attributes_merge) (void *, void *, int *err);
130 
131   /* Release the private data for an simple_object_attributes.  */
132   void (*release_attributes) (void *);
133 
134   /* Start creating an object file.  */
135   void *(*start_write) (void *attributes_data, const char **errmsg,
136 			int *err);
137 
138   /* Write the complete object file.  */
139   const char *(*write_to_file) (simple_object_write *sobj, int descriptor,
140 				int *err);
141 
142   /* Release the private data for an simple_object_write.  */
143   void (*release_write) (void *);
144 
145   /* Copy LTO debug sections.  */
146   const char *(*copy_lto_debug_sections) (simple_object_read *sobj,
147 					  simple_object_write *dobj,
148 					  char *(*pfn) (const char *),
149 					  int *err);
150 };
151 
152 /* The known object file formats.  */
153 
154 extern const struct simple_object_functions simple_object_coff_functions;
155 extern const struct simple_object_functions simple_object_elf_functions;
156 extern const struct simple_object_functions simple_object_mach_o_functions;
157 extern const struct simple_object_functions simple_object_xcoff_functions;
158 
159 /* Read SIZE bytes from DESCRIPTOR at file offset OFFSET into BUFFER.
160    Return non-zero on success.  On failure return 0 and set *ERRMSG
161    and *ERR.  */
162 
163 extern int
164 simple_object_internal_read (int descriptor, off_t offset,
165 			     unsigned char *buffer, size_t size,
166 			     const char **errmsg, int *err);
167 
168 /* Write SIZE bytes from BUFFER to DESCRIPTOR at file offset OFFSET.
169    Return non-zero on success.  On failure return 0 and set *ERRMSG
170    and *ERR.  */
171 
172 extern int
173 simple_object_internal_write (int descriptor, off_t offset,
174 			      const unsigned char *buffer, size_t size,
175 			      const char **errmsg, int *err);
176 
177 /* Define ulong_type as an unsigned 64-bit type if available.
178    Otherwise just make it unsigned long.  */
179 
180 #ifdef UNSIGNED_64BIT_TYPE
181 __extension__ typedef UNSIGNED_64BIT_TYPE ulong_type;
182 #else
183 typedef unsigned long ulong_type;
184 #endif
185 
186 /* Fetch a big-endian 16-bit value.  */
187 
188 static inline unsigned short
189 simple_object_fetch_big_16 (const unsigned char *buf)
190 {
191   return ((unsigned short) buf[0] << 8) | (unsigned short) buf[1];
192 }
193 
194 /* Fetch a little-endian 16-bit value.  */
195 
196 static inline unsigned short
197 simple_object_fetch_little_16 (const unsigned char *buf)
198 {
199   return ((unsigned short) buf[1] << 8) | (unsigned short) buf[0];
200 }
201 
202 /* Fetch a big-endian 32-bit value.  */
203 
204 static inline unsigned int
205 simple_object_fetch_big_32 (const unsigned char *buf)
206 {
207   return (((unsigned int) buf[0] << 24)
208 	  | ((unsigned int) buf[1] << 16)
209 	  | ((unsigned int) buf[2] << 8)
210 	  | (unsigned int) buf[3]);
211 }
212 
213 /* Fetch a little-endian 32-bit value.  */
214 
215 static inline unsigned int
216 simple_object_fetch_little_32 (const unsigned char *buf)
217 {
218   return (((unsigned int) buf[3] << 24)
219 	  | ((unsigned int) buf[2] << 16)
220 	  | ((unsigned int) buf[1] << 8)
221 	  | (unsigned int) buf[0]);
222 }
223 
224 /* Fetch a big-endian 32-bit value as a ulong_type.  */
225 
226 static inline ulong_type
227 simple_object_fetch_big_32_ulong (const unsigned char *buf)
228 {
229   return (ulong_type) simple_object_fetch_big_32 (buf);
230 }
231 
232 /* Fetch a little-endian 32-bit value as a ulong_type.  */
233 
234 static inline ulong_type
235 simple_object_fetch_little_32_ulong (const unsigned char *buf)
236 {
237   return (ulong_type) simple_object_fetch_little_32 (buf);
238 }
239 
240 #ifdef UNSIGNED_64BIT_TYPE
241 
242 /* Fetch a big-endian 64-bit value.  */
243 
244 static inline ulong_type
245 simple_object_fetch_big_64 (const unsigned char *buf)
246 {
247   return (((ulong_type) buf[0] << 56)
248 	  | ((ulong_type) buf[1] << 48)
249 	  | ((ulong_type) buf[2] << 40)
250 	  | ((ulong_type) buf[3] << 32)
251 	  | ((ulong_type) buf[4] << 24)
252 	  | ((ulong_type) buf[5] << 16)
253 	  | ((ulong_type) buf[6] << 8)
254 	  | (ulong_type) buf[7]);
255 }
256 
257 /* Fetch a little-endian 64-bit value.  */
258 
259 static inline ulong_type
260 simple_object_fetch_little_64 (const unsigned char *buf)
261 {
262   return (((ulong_type) buf[7] << 56)
263 	  | ((ulong_type) buf[6] << 48)
264 	  | ((ulong_type) buf[5] << 40)
265 	  | ((ulong_type) buf[4] << 32)
266 	  | ((ulong_type) buf[3] << 24)
267 	  | ((ulong_type) buf[2] << 16)
268 	  | ((ulong_type) buf[1] << 8)
269 	  | (ulong_type) buf[0]);
270 }
271 
272 #endif
273 
274 /* Store a big-endian 16-bit value.  */
275 
276 static inline void
277 simple_object_set_big_16 (unsigned char *buf, unsigned short val)
278 {
279   buf[0] = (val >> 8) & 0xff;
280   buf[1] = val & 0xff;
281 }
282 
283 /* Store a little-endian 16-bit value.  */
284 
285 static inline void
286 simple_object_set_little_16 (unsigned char *buf, unsigned short val)
287 {
288   buf[1] = (val >> 8) & 0xff;
289   buf[0] = val & 0xff;
290 }
291 
292 /* Store a big-endian 32-bit value.  */
293 
294 static inline void
295 simple_object_set_big_32 (unsigned char *buf, unsigned int val)
296 {
297   buf[0] = (val >> 24) & 0xff;
298   buf[1] = (val >> 16) & 0xff;
299   buf[2] = (val >> 8) & 0xff;
300   buf[3] = val & 0xff;
301 }
302 
303 /* Store a little-endian 32-bit value.  */
304 
305 static inline void
306 simple_object_set_little_32 (unsigned char *buf, unsigned int val)
307 {
308   buf[3] = (val >> 24) & 0xff;
309   buf[2] = (val >> 16) & 0xff;
310   buf[1] = (val >> 8) & 0xff;
311   buf[0] = val & 0xff;
312 }
313 
314 /* Store a big-endian 32-bit value coming in as a ulong_type.  */
315 
316 static inline void
317 simple_object_set_big_32_ulong (unsigned char *buf, ulong_type val)
318 {
319   simple_object_set_big_32 (buf, val);
320 }
321 
322 /* Store a little-endian 32-bit value coming in as a ulong_type.  */
323 
324 static inline void
325 simple_object_set_little_32_ulong (unsigned char *buf, ulong_type val)
326 {
327   simple_object_set_little_32 (buf, val);
328 }
329 
330 #ifdef UNSIGNED_64BIT_TYPE
331 
332 /* Store a big-endian 64-bit value.  */
333 
334 static inline void
335 simple_object_set_big_64 (unsigned char *buf, ulong_type val)
336 {
337   buf[0] = (val >> 56) & 0xff;
338   buf[1] = (val >> 48) & 0xff;
339   buf[2] = (val >> 40) & 0xff;
340   buf[3] = (val >> 32) & 0xff;
341   buf[4] = (val >> 24) & 0xff;
342   buf[5] = (val >> 16) & 0xff;
343   buf[6] = (val >> 8) & 0xff;
344   buf[7] = val & 0xff;
345 }
346 
347 /* Store a little-endian 64-bit value.  */
348 
349 static inline void
350 simple_object_set_little_64 (unsigned char *buf, ulong_type val)
351 {
352   buf[7] = (val >> 56) & 0xff;
353   buf[6] = (val >> 48) & 0xff;
354   buf[5] = (val >> 40) & 0xff;
355   buf[4] = (val >> 32) & 0xff;
356   buf[3] = (val >> 24) & 0xff;
357   buf[2] = (val >> 16) & 0xff;
358   buf[1] = (val >> 8) & 0xff;
359   buf[0] = val & 0xff;
360 }
361 
362 #endif
363