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143dce84 NA |
1 | /* Opening CTF files with BFD. |
2 | Copyright (C) 2019 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of libctf. | |
5 | ||
6 | libctf is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 3, or (at your option) any later | |
9 | version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
14 | See the GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; see the file COPYING. If not see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include <ctf-impl.h> | |
21 | #include <stddef.h> | |
22 | #include <sys/types.h> | |
23 | #include <sys/stat.h> | |
24 | #include <errno.h> | |
25 | #include <string.h> | |
26 | #include <fcntl.h> | |
27 | #include <elf.h> | |
28 | #include <bfd.h> | |
29 | ||
30 | #include "elf-bfd.h" | |
31 | ||
32 | /* Make a new struct ctf_archive_internal wrapper for a ctf_archive or a | |
33 | ctf_file. Closes ARC and/or FP on error. Arrange to free the SYMSECT and | |
34 | STRSECT interior on close. */ | |
35 | ||
36 | static struct ctf_archive_internal * | |
37 | ctf_new_archive_internal (int is_archive, struct ctf_archive *arc, | |
38 | ctf_file_t *fp, const ctf_sect_t *symsect, | |
39 | const ctf_sect_t *strsect, | |
40 | int *errp) | |
41 | { | |
42 | struct ctf_archive_internal *arci; | |
43 | ||
44 | if ((arci = calloc (1, sizeof (struct ctf_archive_internal))) == NULL) | |
45 | { | |
46 | if (is_archive) | |
47 | ctf_arc_close_internal (arc); | |
48 | else | |
49 | ctf_file_close (fp); | |
50 | return (ctf_set_open_errno (errp, errno)); | |
51 | } | |
52 | arci->ctfi_is_archive = is_archive; | |
53 | if (is_archive) | |
54 | arci->ctfi_archive = arc; | |
55 | else | |
56 | arci->ctfi_file = fp; | |
57 | if (symsect) | |
58 | memcpy (&arci->ctfi_symsect, symsect, sizeof (struct ctf_sect)); | |
59 | if (strsect) | |
60 | memcpy (&arci->ctfi_strsect, strsect, sizeof (struct ctf_sect)); | |
61 | ||
62 | return arci; | |
63 | } | |
64 | ||
65 | /* Free the BFD bits of a CTF file on ctf_file_close(). */ | |
66 | ||
67 | static void | |
68 | ctf_bfdclose (struct ctf_archive_internal *arci) | |
69 | { | |
70 | if (arci->ctfi_abfd != NULL) | |
71 | if (!bfd_close_all_done (arci->ctfi_abfd)) | |
72 | ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); | |
73 | } | |
74 | ||
75 | /* Open a CTF file given the specified BFD. */ | |
76 | ||
77 | ctf_archive_t * | |
78 | ctf_bfdopen (struct bfd *abfd, int *errp) | |
79 | { | |
80 | ctf_archive_t *arc; | |
81 | asection *ctf_asect; | |
82 | bfd_byte *contents; | |
83 | ctf_sect_t ctfsect; | |
84 | ||
85 | libctf_init_debug(); | |
86 | ||
87 | if ((ctf_asect = bfd_get_section_by_name (abfd, _CTF_SECTION)) == NULL) | |
88 | { | |
89 | return (ctf_set_open_errno (errp, ECTF_NOCTFDATA)); | |
90 | } | |
91 | ||
92 | if (!bfd_malloc_and_get_section (abfd, ctf_asect, &contents)) | |
93 | { | |
94 | ctf_dprintf ("ctf_bfdopen(): cannot malloc CTF section: %s\n", | |
95 | bfd_errmsg (bfd_get_error())); | |
96 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
97 | } | |
98 | ||
99 | ctfsect.cts_name = _CTF_SECTION; | |
100 | ctfsect.cts_type = SHT_PROGBITS; | |
101 | ctfsect.cts_flags = 0; | |
102 | ctfsect.cts_entsize = 1; | |
103 | ctfsect.cts_offset = 0; | |
104 | ctfsect.cts_size = bfd_section_size (abfd, ctf_asect); | |
105 | ctfsect.cts_data = contents; | |
106 | ||
107 | if ((arc = ctf_bfdopen_ctfsect (abfd, &ctfsect, errp)) != NULL) | |
108 | { | |
109 | arc->ctfi_data = (void *) ctfsect.cts_data; | |
110 | return arc; | |
111 | } | |
112 | ||
113 | free (contents); | |
114 | return NULL; /* errno is set for us. */ | |
115 | } | |
116 | ||
117 | /* Open a CTF file given the specified BFD and CTF section (which may contain a | |
118 | CTF archive or a file). Takes ownership of the ctfsect, and frees it | |
119 | later. */ | |
120 | ||
121 | ctf_archive_t * | |
9698cf9b NA |
122 | ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_, |
123 | const ctf_sect_t *ctfsect, int *errp) | |
143dce84 NA |
124 | { |
125 | struct ctf_archive *arc = NULL; | |
126 | ctf_archive_t *arci; | |
127 | ctf_file_t *fp = NULL; | |
128 | ctf_sect_t *symsectp = NULL; | |
129 | ctf_sect_t *strsectp = NULL; | |
130 | const char *bfderrstr = NULL; | |
131 | int is_archive; | |
132 | ||
9698cf9b | 133 | #ifdef HAVE_BFD_ELF |
143dce84 NA |
134 | asection *sym_asect; |
135 | ctf_sect_t symsect, strsect; | |
136 | /* TODO: handle SYMTAB_SHNDX. */ | |
137 | ||
138 | if ((sym_asect = bfd_section_from_elf_index (abfd, | |
139 | elf_onesymtab (abfd))) != NULL) | |
140 | { | |
141 | Elf_Internal_Shdr *symhdr = &elf_symtab_hdr (abfd); | |
142 | asection *str_asect = NULL; | |
143 | bfd_byte *contents; | |
144 | ||
145 | if (symhdr->sh_link != SHN_UNDEF && | |
146 | symhdr->sh_link <= elf_numsections (abfd)) | |
147 | str_asect = bfd_section_from_elf_index (abfd, symhdr->sh_link); | |
148 | ||
149 | Elf_Internal_Shdr *strhdr = elf_elfsections (abfd)[symhdr->sh_link]; | |
150 | ||
151 | if (sym_asect && str_asect) | |
152 | { | |
153 | if (!bfd_malloc_and_get_section (abfd, str_asect, &contents)) | |
154 | { | |
155 | bfderrstr = "Cannot malloc string table"; | |
156 | free (contents); | |
157 | goto err; | |
158 | } | |
159 | strsect.cts_data = contents; | |
160 | strsect.cts_name = (char *) strsect.cts_data + strhdr->sh_name; | |
161 | strsect.cts_type = strhdr->sh_type; | |
162 | strsect.cts_flags = strhdr->sh_flags; | |
163 | strsect.cts_entsize = strhdr->sh_size; | |
164 | strsect.cts_offset = strhdr->sh_offset; | |
165 | strsectp = &strsect; | |
166 | ||
167 | if (!bfd_malloc_and_get_section (abfd, sym_asect, &contents)) | |
168 | { | |
169 | bfderrstr = "Cannot malloc symbol table"; | |
170 | free (contents); | |
171 | goto err_free_str; | |
172 | } | |
173 | ||
174 | symsect.cts_name = (char *) strsect.cts_data + symhdr->sh_name; | |
175 | symsect.cts_type = symhdr->sh_type; | |
176 | symsect.cts_flags = symhdr->sh_flags; | |
177 | symsect.cts_entsize = symhdr->sh_size; | |
178 | symsect.cts_data = contents; | |
179 | symsect.cts_offset = symhdr->sh_offset; | |
180 | symsectp = &symsect; | |
181 | } | |
182 | } | |
9698cf9b | 183 | #endif |
143dce84 NA |
184 | |
185 | if (ctfsect->cts_size > sizeof (uint64_t) && | |
186 | ((*(uint64_t *) ctfsect->cts_data) == CTFA_MAGIC)) | |
187 | { | |
188 | is_archive = 1; | |
189 | if ((arc = ctf_arc_bufopen ((void *) ctfsect->cts_data, | |
190 | ctfsect->cts_size, errp)) == NULL) | |
191 | goto err_free_sym; | |
192 | } | |
193 | else | |
194 | { | |
195 | is_archive = 0; | |
196 | if ((fp = ctf_bufopen (ctfsect, symsectp, strsectp, errp)) == NULL) | |
197 | { | |
198 | ctf_dprintf ("ctf_internal_open(): cannot open CTF: %s\n", | |
199 | ctf_errmsg (*errp)); | |
200 | goto err_free_sym; | |
201 | } | |
202 | } | |
203 | arci = ctf_new_archive_internal (is_archive, arc, fp, symsectp, strsectp, | |
204 | errp); | |
205 | ||
206 | if (arci) | |
207 | return arci; | |
208 | err_free_sym: | |
9698cf9b | 209 | #ifdef HAVE_BFD_ELF |
143dce84 NA |
210 | free ((void *) symsect.cts_data); |
211 | err_free_str: | |
212 | free ((void *) strsect.cts_data); | |
9698cf9b | 213 | #endif |
143dce84 NA |
214 | err: _libctf_unused_; |
215 | if (bfderrstr) | |
216 | { | |
217 | ctf_dprintf ("ctf_bfdopen(): %s: %s\n", bfderrstr, | |
218 | bfd_errmsg (bfd_get_error())); | |
219 | ctf_set_open_errno (errp, ECTF_FMT); | |
220 | } | |
221 | return NULL; | |
222 | } | |
223 | ||
224 | /* Open the specified file descriptor and return a pointer to a CTF archive that | |
225 | contains one or more CTF containers. The file can be an ELF file, a raw CTF | |
226 | file, or a CTF archive. The caller is responsible for closing the file | |
227 | descriptor when it is no longer needed. If this is an ELF file, TARGET, if | |
228 | non-NULL, should be the name of a suitable BFD target. */ | |
229 | ||
230 | ctf_archive_t * | |
231 | ctf_fdopen (int fd, const char *filename, const char *target, int *errp) | |
232 | { | |
233 | ctf_archive_t *arci; | |
234 | bfd *abfd; | |
235 | int nfd; | |
236 | ||
237 | struct stat st; | |
238 | ssize_t nbytes; | |
239 | ||
240 | ctf_preamble_t ctfhdr; | |
241 | uint64_t arc_magic; | |
242 | ||
243 | memset (&ctfhdr, 0, sizeof (ctfhdr)); | |
244 | ||
245 | libctf_init_debug(); | |
246 | ||
247 | if (fstat (fd, &st) == -1) | |
248 | return (ctf_set_open_errno (errp, errno)); | |
249 | ||
250 | if ((nbytes = ctf_pread (fd, &ctfhdr, sizeof (ctfhdr), 0)) <= 0) | |
251 | return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); | |
252 | ||
253 | /* If we have read enough bytes to form a CTF header and the magic | |
254 | string matches, attempt to interpret the file as raw CTF. */ | |
255 | ||
256 | if ((size_t) nbytes >= sizeof (ctf_preamble_t) && | |
257 | ctfhdr.ctp_magic == CTF_MAGIC) | |
258 | { | |
259 | ctf_file_t *fp = NULL; | |
260 | void *data; | |
261 | ||
262 | if (ctfhdr.ctp_version > CTF_VERSION) | |
263 | return (ctf_set_open_errno (errp, ECTF_CTFVERS)); | |
264 | ||
265 | if ((data = ctf_mmap (st.st_size, 0, fd)) == NULL) | |
266 | return (ctf_set_open_errno (errp, errno)); | |
267 | ||
268 | if ((fp = ctf_simple_open (data, (size_t) st.st_size, NULL, 0, 0, | |
269 | NULL, 0, errp)) == NULL) | |
270 | ctf_munmap (data, (size_t) st.st_size); | |
271 | fp->ctf_data_mmapped = data; | |
272 | fp->ctf_data_mmapped_len = (size_t) st.st_size; | |
273 | ||
274 | return ctf_new_archive_internal (0, NULL, fp, NULL, NULL, errp); | |
275 | } | |
276 | ||
277 | if ((nbytes = ctf_pread (fd, &arc_magic, sizeof (arc_magic), 0)) <= 0) | |
278 | return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); | |
279 | ||
280 | if ((size_t) nbytes >= sizeof (uint64_t) && arc_magic == CTFA_MAGIC) | |
281 | { | |
282 | struct ctf_archive *arc; | |
283 | ||
284 | if ((arc = ctf_arc_open_internal (filename, errp)) == NULL) | |
285 | return NULL; /* errno is set for us. */ | |
286 | ||
287 | return ctf_new_archive_internal (1, arc, NULL, NULL, NULL, errp); | |
288 | } | |
289 | ||
290 | /* Attempt to open the file with BFD. We must dup the fd first, since bfd | |
291 | takes ownership of the passed fd. */ | |
292 | ||
293 | if ((nfd = dup (fd)) < 0) | |
294 | return (ctf_set_open_errno (errp, errno)); | |
295 | ||
296 | if ((abfd = bfd_fdopenr (filename, target, nfd)) == NULL) | |
297 | { | |
298 | ctf_dprintf ("Cannot open BFD from %s: %s\n", | |
299 | filename ? filename : "(unknown file)", | |
300 | bfd_errmsg (bfd_get_error())); | |
301 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
302 | } | |
303 | ||
304 | if (!bfd_check_format (abfd, bfd_object)) | |
305 | { | |
306 | ctf_dprintf ("BFD format problem in %s: %s\n", | |
307 | filename ? filename : "(unknown file)", | |
308 | bfd_errmsg (bfd_get_error())); | |
309 | if (bfd_get_error() == bfd_error_file_ambiguously_recognized) | |
310 | return (ctf_set_open_errno (errp, ECTF_BFD_AMBIGUOUS)); | |
311 | else | |
312 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
313 | } | |
314 | ||
315 | if ((arci = ctf_bfdopen (abfd, errp)) == NULL) | |
316 | { | |
317 | if (!bfd_close_all_done (abfd)) | |
318 | ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); | |
319 | return NULL; /* errno is set for us. */ | |
320 | } | |
321 | arci->ctfi_bfd_close = ctf_bfdclose; | |
322 | arci->ctfi_abfd = abfd; | |
323 | ||
324 | return arci; | |
325 | } | |
326 | ||
327 | /* Open the specified file and return a pointer to a CTF container. The file | |
328 | can be either an ELF file or raw CTF file. This is just a convenient | |
329 | wrapper around ctf_fdopen() for callers. */ | |
330 | ||
331 | ctf_archive_t * | |
332 | ctf_open (const char *filename, const char *target, int *errp) | |
333 | { | |
334 | ctf_archive_t *arc; | |
335 | int fd; | |
336 | ||
337 | if ((fd = open (filename, O_RDONLY)) == -1) | |
338 | { | |
339 | if (errp != NULL) | |
340 | *errp = errno; | |
341 | return NULL; | |
342 | } | |
343 | ||
344 | arc = ctf_fdopen (fd, filename, target, errp); | |
345 | (void) close (fd); | |
346 | return arc; | |
347 | } | |
348 | ||
349 | /* Public entry point: open a CTF archive, or CTF file. Returns the archive, or | |
350 | NULL and an error in *err. Despite the fact that this uses CTF archives, it | |
351 | must be in this file to avoid dragging in BFD into non-BFD-using programs. */ | |
352 | ctf_archive_t * | |
353 | ctf_arc_open (const char *filename, int *errp) | |
354 | { | |
355 | return ctf_open (filename, NULL, errp); | |
356 | } |