1/* AIX cross support for collect2.
2 Copyright (C) 2009-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#include "config.h"
21#include "system.h"
22#include "coretypes.h"
23#include "tm.h"
24#include "collect2-aix.h"
25
26#ifdef CROSS_AIX_SUPPORT
27
28/* Read SIZE bytes starting at DATA as a big-endian value. */
29
30static inline bfd_vma
31read_value (char *data, unsigned int size)
32{
33 bfd_vma value;
34 unsigned int i;
35
36 value = 0;
37 for (i = 0; i < size; i++)
38 {
39 value <<= 8;
40 value += (unsigned char) data[i];
41 }
42 return value;
43}
44
45/* FIELD is a char array. Read the contents as a big-endian integer. */
46#define READ_FIELD(FIELD) \
47 read_value (FIELD, sizeof (FIELD))
48
49/* OBJECT is a char pointer to an in-file object of type struct TYPE.
50 Return the address of field FIELD. */
51#define OBJECT_FIELD(OBJECT, TYPE, FIELD) \
52 (OBJECT) + offsetof (struct TYPE, FIELD)
53
54/* Return the size of FIELD, which is a field of struct TYPE. */
55#define FIELD_SIZE(TYPE, FIELD) \
56 sizeof (((struct TYPE *) (0))->FIELD)
57
58/* OBJECT is a char pointer to an in-file object of type struct TYPE.
59 Read the value of field FIELD as a big-endian integer. */
60#define READ_OBJECT(OBJECT, TYPE, FIELD) \
61 read_value (OBJECT_FIELD (OBJECT, TYPE, FIELD), FIELD_SIZE (TYPE, FIELD))
62
63/* Copy FIELD from an external structure of type TYPE at address FROM
64 to an internal structure pointed to by TO. */
65#define COPY_FIELD(TO, FROM, TYPE, FIELD) \
66 ((TO)->FIELD = READ_OBJECT (FROM, TYPE, FIELD))
67
68/* Return true if STRING is less than SIZE bytes long. EXTRA_TERMINATOR
69 is another character (besides '\0') that acts as a terminator,
70 or '\0' if none. */
71
72static bool
73string_within_bounds_p (const char *string, size_t size, char extra_terminator)
74{
75 const char *p;
76
77 for (p = string; p < string + size; p++)
78 if (*p == '\0' || *p == extra_terminator)
79 return true;
80 return false;
81}
82
83/* STRING is a pointer to a char array. Try to read its value as an
84 ASCII-encoded integer. On success, return true and store the result
85 in TARGET. */
86#define PARSE_INTEGER(TARGET, STRING) \
87 (string_within_bounds_p (&(STRING)[0], sizeof (STRING), ' ') \
88 && ((TARGET) = strtoul (STRING, NULL, 0), true))
89
90/* Check that LDFILE's current object has SIZE bytes starting at OFFSET. */
91
92static inline bool
93within_object_p (LDFILE *ldfile, size_t offset, size_t size)
94{
95 return offset <= ldfile->object_size && offset + size <= ldfile->object_size;
96}
97
98/* Try to read the file header for an XCOFF object at OFFSET bytes into
99 LDFILE. The object is expected to be OBJECT_SIZE bytes in size.
100 If the object is a member of an archive, NEXT_MEMBER is the offset
101 of the next member, otherwise it is -1.
102
103 Return true on success, recording the object information in LDFILE. */
104
105static bool
106read_xcoff_object (LDFILE *ldfile, size_t offset, size_t object_size,
107 off_t next_member)
108{
109 struct internal_filehdr *internal;
110 char *external;
111 void *map;
112 size_t page_size;
113
114 /* First try to map the file into memory. */
115 page_size = getpagesize ();
116 ldfile->page_offset = offset & (page_size - 1);
117 map = mmap (NULL, object_size + ldfile->page_offset, PROT_READ,
118 MAP_SHARED, ldfile->fd, offset - ldfile->page_offset);
119 if (map == MAP_FAILED)
120 return false;
121
122 /* Record the success. */
123 ldfile->object = (char *) map + ldfile->page_offset;
124 ldfile->object_size = object_size;
125 ldfile->next_member = next_member;
126
127 /* Read the magic value to determine the type of file. */
128 if (!within_object_p (ldfile, 0, F_MAGIC_SIZE))
129 return false;
130
131 internal = &ldfile->filehdr;
132 external = ldfile->object;
133 internal->f_magic = read_value (external, F_MAGIC_SIZE);
134 if (internal->f_magic == U802TOCMAGIC)
135 {
136 if (!within_object_p (ldfile, 0, sizeof (struct external_filehdr_32)))
137 return false;
138
139 COPY_FIELD (internal, external, external_filehdr_32, f_nscns);
140 COPY_FIELD (internal, external, external_filehdr_32, f_timdat);
141 COPY_FIELD (internal, external, external_filehdr_32, f_symptr);
142 COPY_FIELD (internal, external, external_filehdr_32, f_nsyms);
143 COPY_FIELD (internal, external, external_filehdr_32, f_opthdr);
144 COPY_FIELD (internal, external, external_filehdr_32, f_flags);
145 return true;
146 }
147 else if (internal->f_magic == U803XTOCMAGIC
148 || internal->f_magic == U64_TOCMAGIC)
149 {
150 if (!within_object_p (ldfile, 0, sizeof (struct external_filehdr_64)))
151 return false;
152
153 COPY_FIELD (internal, external, external_filehdr_64, f_nscns);
154 COPY_FIELD (internal, external, external_filehdr_64, f_timdat);
155 COPY_FIELD (internal, external, external_filehdr_64, f_symptr);
156 COPY_FIELD (internal, external, external_filehdr_64, f_nsyms);
157 COPY_FIELD (internal, external, external_filehdr_64, f_opthdr);
158 COPY_FIELD (internal, external, external_filehdr_64, f_flags);
159 return true;
160 }
161 return false;
162}
163
164/* Try to read an archive member at OFFSET bytes into LDFILE.
165 Return true on success, recording the member and object
166 information in LDFILE. */
167
168static bool
169read_archive_member (LDFILE *ldfile, size_t offset)
170{
171 struct external_big_ar_member member;
172 size_t namlen;
173 size_t size;
174 off_t next_member;
175
176 if (lseek (ldfile->fd, offset, SEEK_SET) >= 0
177 && read (ldfile->fd, &member, sizeof (member)) == sizeof (member)
178 && PARSE_INTEGER (namlen, member.ar_namlen)
179 /* Stop once we reach the member table entry, which has a name
180 of length 0. */
181 && namlen > 0
182 && PARSE_INTEGER (size, member.ar_size)
183 && PARSE_INTEGER (next_member, member.ar_nextoff))
184 {
185 /* The archive is followed by an even-padded name, then by
186 a magic string of length SXCOFFARFMAG. The object itself
187 starts after that. */
188 offset += sizeof (member) + namlen + SXCOFFARFMAG;
189 offset += offset & 1;
190 return read_xcoff_object (ldfile, offset, size, next_member);
191 }
192 return false;
193}
194
195/* Try to treat LDFILE as a non-empty big archive. Return true
196 on success, storing the member and object information for
197 the first member in LDFILE. */
198
199static bool
200read_big_archive (LDFILE *ldfile)
201{
202 struct external_big_ar_filehdr filehdr;
203 size_t offset;
204
205 return (lseek (ldfile->fd, 0L, SEEK_SET) == 0
206 && read (ldfile->fd, &filehdr, sizeof (filehdr)) == sizeof (filehdr)
207 && memcmp (filehdr.fl_magic, FL_MAGIC_BIG_AR, FL_MAGIC_SIZE) == 0
208 && PARSE_INTEGER (offset, filehdr.fl_firstmemoff)
209 && read_archive_member (ldfile, offset));
210}
211
212/* LDFILE is a zero-initialized structure. Try to open FILENAME,
213 returning true on success. */
214
215static bool
216open_file (LDFILE *ldfile, const char *filename)
217{
218 struct stat st;
219
220 ldfile->fd = open (filename, O_RDONLY);
221 if (ldfile->fd < 0)
222 return false;
223
224 if (read_big_archive (ldfile))
225 return true;
226
227 if (fstat (ldfile->fd, &st) < 0)
228 return false;
229
230 return read_xcoff_object (ldfile, 0, st.st_size, -1);
231}
232
233/* Release the memory associated with the current object, if one has
234 been mapped. */
235
236static void
237free_object (LDFILE *ldfile)
238{
239 if (ldfile->object)
240 munmap (ldfile->object - ldfile->page_offset,
241 ldfile->object_size + ldfile->page_offset);
242}
243
244/* Free LDFILE and all resources associated with it. */
245
246static void
247free_ldfile (LDFILE *ldfile)
248{
249 if (ldfile->fd >= 0)
250 close (ldfile->fd);
251 XDELETE (ldfile);
252}
253
254/* Implement the API-defined ldopen function. */
255
256LDFILE *
257ldopen (char *filename, LDFILE *ldfile)
258{
259 if (ldfile == NULL)
260 {
261 ldfile = XCNEW (LDFILE);
262 if (!open_file (ldfile, filename))
263 {
264 free_object (ldfile);
265 free_ldfile (ldfile);
266 return NULL;
267 }
268 }
269 return ldfile;
270}
271
272/* Implement the API-defined ldtbread function. */
273
274int
275ldtbread (LDFILE *ldfile, long index, SYMENT *internal)
276{
277 size_t offset, name_length;
278 char *external;
279
280 /* Make sure that the symbol index is valid. */
281 if (index < 0 || index >= HEADER (ldfile).f_nsyms)
282 return FAILURE;
283
284 /* Work out the offset of the symbol table entry. */
285 offset = HEADER (ldfile).f_symptr + index * sizeof (struct external_syment);
286 if (!within_object_p (ldfile, offset, sizeof (struct external_syment)))
287 return FAILURE;
288
289 /* Read all the fields. The format differs between 32-bit and
290 64-bit files. */
291 external = ldfile->object + offset;
292 if (HEADER (ldfile).f_magic == U802TOCMAGIC)
293 {
294 /* Copy the n_zeroes/n_offset interpretation. */
295 internal->n_zeroes = READ_OBJECT (external, external_syment,
296 u.xcoff32.u.u.n_zeroes);
297 internal->n_offset = READ_OBJECT (external, external_syment,
298 u.xcoff32.u.u.n_offset);
299
300 /* Copy the n_name interpretation. The internal version has room
301 for a null terminator. */
302 name_length = FIELD_SIZE (external_syment, u.xcoff32.u.n_name);
303 memcpy (internal->n_name,
304 external + offsetof (struct external_syment, u.xcoff32.u.n_name),
305 name_length);
306 internal->n_name[name_length] = 0;
307
308 internal->n_value = READ_OBJECT (external, external_syment,
309 u.xcoff32.n_value);
310 }
311 else
312 {
313 internal->n_zeroes = 0;
314 internal->n_offset = READ_OBJECT (external, external_syment,
315 u.xcoff64.n_offset);
316 internal->n_value = READ_OBJECT (external, external_syment,
317 u.xcoff64.n_value);
318 }
319 COPY_FIELD (internal, external, external_syment, n_scnum);
320 COPY_FIELD (internal, external, external_syment, n_type);
321 COPY_FIELD (internal, external, external_syment, n_sclass);
322 COPY_FIELD (internal, external, external_syment, n_numaux);
323 return SUCCESS;
324}
325
326/* Implement the API-defined ldgetname function. */
327
328char *
329ldgetname (LDFILE *ldfile, SYMENT *symbol)
330{
331 char *name;
332 size_t offset;
333
334 /* If the zeroes field is nonzero, the name is in the symbol table
335 entry itself. */
336 if (symbol->n_zeroes != 0)
337 return symbol->n_name;
338
339 /* Otherwise, the symbol table entry contains an offset into the
340 string table, which starts after the end of the symbol table. */
341 offset = (HEADER (ldfile).f_symptr
342 + HEADER (ldfile).f_nsyms * sizeof (struct external_syment)
343 + symbol->n_offset);
344 if (offset >= ldfile->object_size)
345 return NULL;
346
347 /* Make sure that the name is entirely contained within the object. */
348 name = ldfile->object + offset;
349 if (!string_within_bounds_p (name, ldfile->object_size - offset, '\0'))
350 return NULL;
351
352 return name;
353}
354
355/* Implement the API-defined ldclose function. */
356
357int
358ldclose (LDFILE *ldfile)
359{
360 free_object (ldfile);
361 if (ldfile->next_member >= 0
362 && read_archive_member (ldfile, ldfile->next_member))
363 return FAILURE;
364
365 free_ldfile (ldfile);
366 return SUCCESS;
367}
368
369#endif
370