1 /* Definitions for BFD wrappers used by GDB.
3 Copyright (C) 2011, 2012
4 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "gdb_assert.h"
24 #include "gdb_string.h"
34 #define MAP_FAILED ((void *) -1)
38 /* An object of this type is stored in the section's user data when
41 struct gdb_bfd_section_data
43 /* Size of the data. */
45 /* If the data was mmapped, this is the length of the map. */
46 bfd_size_type map_len;
47 /* The data. If NULL, the section data has not been read. */
49 /* If the data was mmapped, this is the map address. */
53 /* A hash table holding every BFD that gdb knows about. This is not
54 to be confused with 'gdb_bfd_cache', which is used for sharing
55 BFDs; in contrast, this hash is used just to implement
58 static htab_t all_bfds;
63 gdb_bfd_stash_filename (struct bfd *abfd)
65 char *name = bfd_get_filename (abfd);
68 data = bfd_alloc (abfd, strlen (name) + 1);
71 /* Unwarranted chumminess with BFD. */
72 abfd->filename = data;
75 /* An object of this type is stored in each BFD's user data. */
79 /* The reference count. */
82 /* The mtime of the BFD at the point the cache entry was made. */
86 /* A hash table storing all the BFDs maintained in the cache. */
88 static htab_t gdb_bfd_cache;
90 /* The type of an object being looked up in gdb_bfd_cache. We use
91 htab's capability of storing one kind of object (BFD in this case)
92 and using a different sort of object for searching. */
94 struct gdb_bfd_cache_search
102 /* A hash function for BFDs. */
105 hash_bfd (const void *b)
109 /* It is simplest to just hash the filename. */
110 return htab_hash_string (bfd_get_filename (abfd));
113 /* An equality function for BFDs. Note that this expects the caller
114 to search using struct gdb_bfd_cache_search only, not BFDs. */
117 eq_bfd (const void *a, const void *b)
120 const struct gdb_bfd_cache_search *s = b;
121 struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
123 return (gdata->mtime == s->mtime
124 && strcmp (bfd_get_filename (abfd), s->filename) == 0);
130 gdb_bfd_open (const char *name, const char *target, int fd)
135 struct gdb_bfd_cache_search search;
138 if (gdb_bfd_cache == NULL)
139 gdb_bfd_cache = htab_create_alloc (1, hash_bfd, eq_bfd, NULL,
144 fd = open (name, O_RDONLY | O_BINARY);
147 bfd_set_error (bfd_error_system_call);
152 search.filename = name;
153 if (fstat (fd, &st) < 0)
155 /* Weird situation here. */
159 search.mtime = st.st_mtime;
161 /* Note that this must compute the same result as hash_bfd. */
162 hash = htab_hash_string (name);
163 /* Note that we cannot use htab_find_slot_with_hash here, because
164 opening the BFD may fail; and this would violate hashtab
166 abfd = htab_find_with_hash (gdb_bfd_cache, &search, hash);
174 abfd = bfd_fopen (name, target, FOPEN_RB, fd);
178 slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, INSERT);
182 gdb_bfd_stash_filename (abfd);
187 /* A helper function that releases any section data attached to the
191 free_one_bfd_section (bfd *abfd, asection *sectp, void *ignore)
193 struct gdb_bfd_section_data *sect = bfd_get_section_userdata (abfd, sectp);
195 if (sect != NULL && sect->data != NULL)
198 if (sect->map_addr != NULL)
202 res = munmap (sect->map_addr, sect->map_len);
203 gdb_assert (res == 0);
211 /* Close ABFD, and warn if that fails. */
214 gdb_bfd_close_or_warn (struct bfd *abfd)
217 char *name = bfd_get_filename (abfd);
219 bfd_map_over_sections (abfd, free_one_bfd_section, NULL);
221 ret = bfd_close (abfd);
224 warning (_("cannot close \"%s\": %s"),
225 name, bfd_errmsg (bfd_get_error ()));
233 gdb_bfd_ref (struct bfd *abfd)
235 struct gdb_bfd_data *gdata;
241 gdata = bfd_usrdata (abfd);
249 gdata = bfd_zalloc (abfd, sizeof (struct gdb_bfd_data));
251 gdata->mtime = bfd_get_mtime (abfd);
252 bfd_usrdata (abfd) = gdata;
254 /* This is the first we've seen it, so add it to the hash table. */
255 slot = htab_find_slot (all_bfds, abfd, INSERT);
256 gdb_assert (slot && !*slot);
263 gdb_bfd_unref (struct bfd *abfd)
265 struct gdb_bfd_data *gdata;
266 struct gdb_bfd_cache_search search;
272 gdata = bfd_usrdata (abfd);
273 gdb_assert (gdata->refc >= 1);
279 search.filename = bfd_get_filename (abfd);
281 if (gdb_bfd_cache && search.filename)
283 hashval_t hash = htab_hash_string (search.filename);
286 search.mtime = gdata->mtime;
287 slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash,
291 htab_clear_slot (gdb_bfd_cache, slot);
294 bfd_usrdata (abfd) = NULL; /* Paranoia. */
296 htab_remove_elt (all_bfds, abfd);
298 gdb_bfd_close_or_warn (abfd);
301 /* A helper function that returns the section data descriptor
302 associated with SECTION. If no such descriptor exists, a new one
303 is allocated and cleared. */
305 static struct gdb_bfd_section_data *
306 get_section_descriptor (asection *section)
308 struct gdb_bfd_section_data *result;
310 result = bfd_get_section_userdata (section->owner, section);
314 result = bfd_zalloc (section->owner, sizeof (*result));
315 bfd_set_section_userdata (section->owner, section, result);
321 /* Decompress a section that was compressed using zlib. Store the
322 decompressed buffer, and its size, in DESCRIPTOR. */
325 zlib_decompress_section (asection *sectp,
326 struct gdb_bfd_section_data *descriptor)
328 bfd *abfd = sectp->owner;
330 error (_("Support for zlib-compressed data (from '%s', section '%s') "
331 "is disabled in this copy of GDB"),
332 bfd_get_filename (abfd),
333 bfd_get_section_name (abfd, sectp));
335 bfd_size_type compressed_size = bfd_get_section_size (sectp);
336 gdb_byte *compressed_buffer = xmalloc (compressed_size);
337 struct cleanup *cleanup = make_cleanup (xfree, compressed_buffer);
338 struct cleanup *inner_cleanup;
339 bfd_size_type uncompressed_size;
340 gdb_byte *uncompressed_buffer;
343 int header_size = 12;
344 struct dwarf2_per_bfd_section *section_data;
346 if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
347 || bfd_bread (compressed_buffer,
348 compressed_size, abfd) != compressed_size)
349 error (_("can't read data from '%s', section '%s'"),
350 bfd_get_filename (abfd),
351 bfd_get_section_name (abfd, sectp));
353 /* Read the zlib header. In this case, it should be "ZLIB" followed
354 by the uncompressed section size, 8 bytes in big-endian order. */
355 if (compressed_size < header_size
356 || strncmp (compressed_buffer, "ZLIB", 4) != 0)
357 error (_("corrupt ZLIB header from '%s', section '%s'"),
358 bfd_get_filename (abfd),
359 bfd_get_section_name (abfd, sectp));
360 uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
361 uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
362 uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
363 uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
364 uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
365 uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
366 uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
367 uncompressed_size += compressed_buffer[11];
369 /* It is possible the section consists of several compressed
370 buffers concatenated together, so we uncompress in a loop. */
374 strm.avail_in = compressed_size - header_size;
375 strm.next_in = (Bytef*) compressed_buffer + header_size;
376 strm.avail_out = uncompressed_size;
377 uncompressed_buffer = xmalloc (uncompressed_size);
378 inner_cleanup = make_cleanup (xfree, uncompressed_buffer);
379 rc = inflateInit (&strm);
380 while (strm.avail_in > 0)
383 error (_("setting up uncompression in '%s', section '%s': %d"),
384 bfd_get_filename (abfd),
385 bfd_get_section_name (abfd, sectp),
387 strm.next_out = ((Bytef*) uncompressed_buffer
388 + (uncompressed_size - strm.avail_out));
389 rc = inflate (&strm, Z_FINISH);
390 if (rc != Z_STREAM_END)
391 error (_("zlib error uncompressing from '%s', section '%s': %d"),
392 bfd_get_filename (abfd),
393 bfd_get_section_name (abfd, sectp),
395 rc = inflateReset (&strm);
397 rc = inflateEnd (&strm);
399 || strm.avail_out != 0)
400 error (_("concluding uncompression in '%s', section '%s': %d"),
401 bfd_get_filename (abfd),
402 bfd_get_section_name (abfd, sectp),
405 discard_cleanups (inner_cleanup);
406 do_cleanups (cleanup);
408 /* Attach the data to the BFD section. */
409 descriptor->data = uncompressed_buffer;
410 descriptor->size = uncompressed_size;
417 gdb_bfd_map_section (asection *sectp, bfd_size_type *size)
420 gdb_byte *buf, *retbuf;
421 unsigned char header[4];
422 struct gdb_bfd_section_data *descriptor;
424 gdb_assert ((sectp->flags & SEC_RELOC) == 0);
425 gdb_assert (size != NULL);
429 descriptor = get_section_descriptor (sectp);
431 /* If the data was already read for this BFD, just reuse it. */
432 if (descriptor->data != NULL)
435 /* Check if the file has a 4-byte header indicating compression. */
436 if (bfd_get_section_size (sectp) > sizeof (header)
437 && bfd_seek (abfd, sectp->filepos, SEEK_SET) == 0
438 && bfd_bread (header, sizeof (header), abfd) == sizeof (header))
440 /* Upon decompression, update the buffer and its size. */
441 if (strncmp (header, "ZLIB", sizeof (header)) == 0)
443 zlib_decompress_section (sectp, descriptor);
450 /* The page size, used when mmapping. */
454 pagesize = getpagesize ();
456 /* Only try to mmap sections which are large enough: we don't want
457 to waste space due to fragmentation. */
459 if (bfd_get_section_size (sectp) > 4 * pagesize)
461 descriptor->size = bfd_get_section_size (sectp);
462 descriptor->data = bfd_mmap (abfd, 0, descriptor->size, PROT_READ,
463 MAP_PRIVATE, sectp->filepos,
464 &descriptor->map_addr,
465 &descriptor->map_len);
467 if ((caddr_t)descriptor->data != MAP_FAILED)
469 #if HAVE_POSIX_MADVISE
470 posix_madvise (descriptor->map_addr, descriptor->map_len,
471 POSIX_MADV_WILLNEED);
476 /* On failure, clear out the section data and try again. */
477 memset (descriptor, 0, sizeof (*descriptor));
480 #endif /* HAVE_MMAP */
482 /* If we get here, we are a normal, not-compressed section. */
484 descriptor->size = bfd_get_section_size (sectp);
485 descriptor->data = xmalloc (descriptor->size);
487 if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
488 || bfd_bread (descriptor->data, bfd_get_section_size (sectp),
489 abfd) != bfd_get_section_size (sectp))
491 xfree (descriptor->data);
492 descriptor->data = NULL;
493 error (_("Can't read data for section '%s'"),
494 bfd_get_filename (abfd));
498 gdb_assert (descriptor->data != NULL);
499 *size = descriptor->size;
500 return descriptor->data;
508 gdb_bfd_fopen (const char *filename, const char *target, const char *mode,
511 bfd *result = bfd_fopen (filename, target, mode, fd);
515 gdb_bfd_stash_filename (result);
516 gdb_bfd_ref (result);
525 gdb_bfd_openr (const char *filename, const char *target)
527 bfd *result = bfd_openr (filename, target);
531 gdb_bfd_stash_filename (result);
532 gdb_bfd_ref (result);
541 gdb_bfd_openw (const char *filename, const char *target)
543 bfd *result = bfd_openw (filename, target);
547 gdb_bfd_stash_filename (result);
548 gdb_bfd_ref (result);
557 gdb_bfd_openr_iovec (const char *filename, const char *target,
558 void *(*open_func) (struct bfd *nbfd,
561 file_ptr (*pread_func) (struct bfd *nbfd,
566 int (*close_func) (struct bfd *nbfd,
568 int (*stat_func) (struct bfd *abfd,
572 bfd *result = bfd_openr_iovec (filename, target,
573 open_func, open_closure,
574 pread_func, close_func, stat_func);
578 gdb_bfd_ref (result);
579 gdb_bfd_stash_filename (result);
588 gdb_bfd_openr_next_archived_file (bfd *archive, bfd *previous)
590 bfd *result = bfd_openr_next_archived_file (archive, previous);
594 gdb_bfd_ref (result);
595 /* No need to stash the filename here. */
604 gdb_bfd_fdopenr (const char *filename, const char *target, int fd)
606 bfd *result = bfd_fdopenr (filename, target, fd);
610 gdb_bfd_ref (result);
611 gdb_bfd_stash_filename (result);
619 /* A callback for htab_traverse that prints a single BFD. */
622 print_one_bfd (void **slot, void *data)
625 struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
626 struct ui_out *uiout = data;
627 struct cleanup *inner;
629 inner = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
630 ui_out_field_int (uiout, "refcount", gdata->refc);
631 ui_out_field_string (uiout, "addr", host_address_to_string (abfd));
632 ui_out_field_string (uiout, "filename", bfd_get_filename (abfd));
633 ui_out_text (uiout, "\n");
639 /* Implement the 'maint info bfd' command. */
642 maintenance_info_bfds (char *arg, int from_tty)
644 struct cleanup *cleanup;
645 struct ui_out *uiout = current_uiout;
647 cleanup = make_cleanup_ui_out_table_begin_end (uiout, 3, -1, "bfds");
648 ui_out_table_header (uiout, 10, ui_left, "refcount", "Refcount");
649 ui_out_table_header (uiout, 18, ui_left, "addr", "Address");
650 ui_out_table_header (uiout, 40, ui_left, "filename", "Filename");
652 ui_out_table_body (uiout);
653 htab_traverse (all_bfds, print_one_bfd, uiout);
655 do_cleanups (cleanup);
658 /* -Wmissing-prototypes */
659 extern initialize_file_ftype _initialize_gdb_bfd;
662 _initialize_gdb_bfd (void)
664 all_bfds = htab_create_alloc (10, htab_hash_pointer, htab_eq_pointer,
665 NULL, xcalloc, xfree);
667 add_cmd ("bfds", class_maintenance, maintenance_info_bfds, _("\
668 List the BFDs that are currently open."),
669 &maintenanceinfolist);