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143dce84 | 1 | /* Opening CTF files with BFD. |
b3adc24a | 2 | Copyright (C) 2019-2020 Free Software Foundation, Inc. |
143dce84 NA |
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> | |
6d5944fc | 22 | #include <assert.h> |
143dce84 NA |
23 | #include <sys/types.h> |
24 | #include <sys/stat.h> | |
25 | #include <errno.h> | |
26 | #include <string.h> | |
27 | #include <fcntl.h> | |
c1401ecc | 28 | #include <unistd.h> |
143dce84 NA |
29 | #include <elf.h> |
30 | #include <bfd.h> | |
cf02c44d NA |
31 | #include "swap.h" |
32 | #include "ctf-endian.h" | |
143dce84 NA |
33 | |
34 | #include "elf-bfd.h" | |
35 | ||
f046147d | 36 | /* Free the BFD bits of a CTF file on ctf_arc_close(). */ |
143dce84 NA |
37 | |
38 | static void | |
39 | ctf_bfdclose (struct ctf_archive_internal *arci) | |
40 | { | |
41 | if (arci->ctfi_abfd != NULL) | |
42 | if (!bfd_close_all_done (arci->ctfi_abfd)) | |
43 | ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); | |
44 | } | |
45 | ||
46 | /* Open a CTF file given the specified BFD. */ | |
47 | ||
48 | ctf_archive_t * | |
49 | ctf_bfdopen (struct bfd *abfd, int *errp) | |
50 | { | |
51 | ctf_archive_t *arc; | |
52 | asection *ctf_asect; | |
53 | bfd_byte *contents; | |
54 | ctf_sect_t ctfsect; | |
55 | ||
56 | libctf_init_debug(); | |
57 | ||
58 | if ((ctf_asect = bfd_get_section_by_name (abfd, _CTF_SECTION)) == NULL) | |
59 | { | |
60 | return (ctf_set_open_errno (errp, ECTF_NOCTFDATA)); | |
61 | } | |
62 | ||
63 | if (!bfd_malloc_and_get_section (abfd, ctf_asect, &contents)) | |
64 | { | |
65 | ctf_dprintf ("ctf_bfdopen(): cannot malloc CTF section: %s\n", | |
66 | bfd_errmsg (bfd_get_error())); | |
67 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
68 | } | |
69 | ||
70 | ctfsect.cts_name = _CTF_SECTION; | |
143dce84 | 71 | ctfsect.cts_entsize = 1; |
fd361982 | 72 | ctfsect.cts_size = bfd_section_size (ctf_asect); |
143dce84 NA |
73 | ctfsect.cts_data = contents; |
74 | ||
75 | if ((arc = ctf_bfdopen_ctfsect (abfd, &ctfsect, errp)) != NULL) | |
76 | { | |
2f6ecaed | 77 | /* This frees the cts_data later. */ |
143dce84 NA |
78 | arc->ctfi_data = (void *) ctfsect.cts_data; |
79 | return arc; | |
80 | } | |
81 | ||
82 | free (contents); | |
83 | return NULL; /* errno is set for us. */ | |
84 | } | |
85 | ||
86 | /* Open a CTF file given the specified BFD and CTF section (which may contain a | |
2f6ecaed | 87 | CTF archive or a file). */ |
143dce84 NA |
88 | |
89 | ctf_archive_t * | |
9698cf9b NA |
90 | ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_, |
91 | const ctf_sect_t *ctfsect, int *errp) | |
143dce84 | 92 | { |
143dce84 | 93 | ctf_archive_t *arci; |
143dce84 NA |
94 | ctf_sect_t *symsectp = NULL; |
95 | ctf_sect_t *strsectp = NULL; | |
96 | const char *bfderrstr = NULL; | |
143dce84 | 97 | |
9698cf9b | 98 | #ifdef HAVE_BFD_ELF |
143dce84 | 99 | ctf_sect_t symsect, strsect; |
6d5944fc NA |
100 | Elf_Internal_Shdr *strhdr; |
101 | Elf_Internal_Shdr *symhdr = &elf_symtab_hdr (abfd); | |
102 | size_t symcount = symhdr->sh_size / symhdr->sh_entsize; | |
103 | Elf_Internal_Sym *isymbuf; | |
104 | bfd_byte *symtab; | |
105 | const char *strtab = NULL; | |
143dce84 NA |
106 | /* TODO: handle SYMTAB_SHNDX. */ |
107 | ||
6d5944fc | 108 | if ((symtab = malloc (symhdr->sh_size)) == NULL) |
143dce84 | 109 | { |
6d5944fc NA |
110 | bfderrstr = "Cannot malloc symbol table"; |
111 | goto err; | |
112 | } | |
143dce84 | 113 | |
6d5944fc NA |
114 | isymbuf = bfd_elf_get_elf_syms (abfd, symhdr, symcount, 0, |
115 | NULL, symtab, NULL); | |
116 | free (isymbuf); | |
117 | if (isymbuf == NULL) | |
118 | { | |
119 | bfderrstr = "Cannot read symbol table"; | |
120 | goto err_free_sym; | |
121 | } | |
143dce84 | 122 | |
6d5944fc NA |
123 | if (elf_elfsections (abfd) != NULL |
124 | && symhdr->sh_link < elf_numsections (abfd)) | |
125 | { | |
126 | strhdr = elf_elfsections (abfd)[symhdr->sh_link]; | |
127 | if (strhdr->contents == NULL) | |
143dce84 | 128 | { |
6d5944fc | 129 | if ((strtab = bfd_elf_get_str_section (abfd, symhdr->sh_link)) == NULL) |
143dce84 | 130 | { |
6d5944fc NA |
131 | bfderrstr = "Cannot read string table"; |
132 | goto err_free_sym; | |
143dce84 | 133 | } |
143dce84 | 134 | } |
6d5944fc NA |
135 | else |
136 | strtab = (const char *) strhdr->contents; | |
137 | } | |
138 | ||
139 | if (strtab) | |
140 | { | |
141 | /* The names here are more or less arbitrary, but there is no point | |
142 | thrashing around digging the name out of the shstrtab given that we don't | |
143 | use it for anything but debugging. */ | |
144 | ||
145 | strsect.cts_data = strtab; | |
146 | strsect.cts_name = ".strtab"; | |
147 | strsect.cts_size = strhdr->sh_size; | |
148 | strsectp = &strsect; | |
149 | ||
150 | assert (symhdr->sh_entsize == get_elf_backend_data (abfd)->s->sizeof_sym); | |
151 | symsect.cts_name = ".symtab"; | |
152 | symsect.cts_entsize = symhdr->sh_entsize; | |
153 | symsect.cts_size = symhdr->sh_size; | |
154 | symsect.cts_data = symtab; | |
155 | symsectp = &symsect; | |
143dce84 | 156 | } |
9698cf9b | 157 | #endif |
143dce84 | 158 | |
2f6ecaed NA |
159 | arci = ctf_arc_bufopen (ctfsect, symsectp, strsectp, errp); |
160 | if (arci) | |
143dce84 | 161 | { |
2f6ecaed NA |
162 | /* Request freeing of the symsect. */ |
163 | arci->ctfi_free_symsect = 1; | |
164 | return arci; | |
143dce84 | 165 | } |
9698cf9b | 166 | #ifdef HAVE_BFD_ELF |
6d5944fc NA |
167 | err_free_sym: |
168 | free (symtab); | |
9698cf9b | 169 | #endif |
143dce84 NA |
170 | err: _libctf_unused_; |
171 | if (bfderrstr) | |
172 | { | |
173 | ctf_dprintf ("ctf_bfdopen(): %s: %s\n", bfderrstr, | |
174 | bfd_errmsg (bfd_get_error())); | |
175 | ctf_set_open_errno (errp, ECTF_FMT); | |
176 | } | |
177 | return NULL; | |
178 | } | |
179 | ||
180 | /* Open the specified file descriptor and return a pointer to a CTF archive that | |
181 | contains one or more CTF containers. The file can be an ELF file, a raw CTF | |
182 | file, or a CTF archive. The caller is responsible for closing the file | |
183 | descriptor when it is no longer needed. If this is an ELF file, TARGET, if | |
184 | non-NULL, should be the name of a suitable BFD target. */ | |
185 | ||
186 | ctf_archive_t * | |
187 | ctf_fdopen (int fd, const char *filename, const char *target, int *errp) | |
188 | { | |
189 | ctf_archive_t *arci; | |
190 | bfd *abfd; | |
191 | int nfd; | |
192 | ||
193 | struct stat st; | |
194 | ssize_t nbytes; | |
195 | ||
196 | ctf_preamble_t ctfhdr; | |
197 | uint64_t arc_magic; | |
198 | ||
199 | memset (&ctfhdr, 0, sizeof (ctfhdr)); | |
200 | ||
201 | libctf_init_debug(); | |
202 | ||
203 | if (fstat (fd, &st) == -1) | |
204 | return (ctf_set_open_errno (errp, errno)); | |
205 | ||
206 | if ((nbytes = ctf_pread (fd, &ctfhdr, sizeof (ctfhdr), 0)) <= 0) | |
207 | return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); | |
208 | ||
cf02c44d NA |
209 | /* If we have read enough bytes to form a CTF header and the magic string |
210 | matches, in either endianness, attempt to interpret the file as raw | |
211 | CTF. */ | |
143dce84 | 212 | |
cf02c44d NA |
213 | if ((size_t) nbytes >= sizeof (ctf_preamble_t) |
214 | && (ctfhdr.ctp_magic == CTF_MAGIC | |
215 | || ctfhdr.ctp_magic == bswap_16 (CTF_MAGIC))) | |
143dce84 NA |
216 | { |
217 | ctf_file_t *fp = NULL; | |
218 | void *data; | |
219 | ||
143dce84 NA |
220 | if ((data = ctf_mmap (st.st_size, 0, fd)) == NULL) |
221 | return (ctf_set_open_errno (errp, errno)); | |
222 | ||
223 | if ((fp = ctf_simple_open (data, (size_t) st.st_size, NULL, 0, 0, | |
224 | NULL, 0, errp)) == NULL) | |
cf02c44d NA |
225 | { |
226 | ctf_munmap (data, (size_t) st.st_size); | |
227 | return NULL; /* errno is set for us. */ | |
228 | } | |
229 | ||
143dce84 NA |
230 | fp->ctf_data_mmapped = data; |
231 | fp->ctf_data_mmapped_len = (size_t) st.st_size; | |
232 | ||
233 | return ctf_new_archive_internal (0, NULL, fp, NULL, NULL, errp); | |
234 | } | |
235 | ||
236 | if ((nbytes = ctf_pread (fd, &arc_magic, sizeof (arc_magic), 0)) <= 0) | |
237 | return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); | |
238 | ||
cf02c44d | 239 | if ((size_t) nbytes >= sizeof (uint64_t) && le64toh (arc_magic) == CTFA_MAGIC) |
143dce84 NA |
240 | { |
241 | struct ctf_archive *arc; | |
242 | ||
243 | if ((arc = ctf_arc_open_internal (filename, errp)) == NULL) | |
244 | return NULL; /* errno is set for us. */ | |
245 | ||
246 | return ctf_new_archive_internal (1, arc, NULL, NULL, NULL, errp); | |
247 | } | |
248 | ||
249 | /* Attempt to open the file with BFD. We must dup the fd first, since bfd | |
250 | takes ownership of the passed fd. */ | |
251 | ||
252 | if ((nfd = dup (fd)) < 0) | |
253 | return (ctf_set_open_errno (errp, errno)); | |
254 | ||
255 | if ((abfd = bfd_fdopenr (filename, target, nfd)) == NULL) | |
256 | { | |
257 | ctf_dprintf ("Cannot open BFD from %s: %s\n", | |
258 | filename ? filename : "(unknown file)", | |
259 | bfd_errmsg (bfd_get_error())); | |
260 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
261 | } | |
edc8bbe9 | 262 | bfd_set_cacheable (abfd, 1); |
143dce84 NA |
263 | |
264 | if (!bfd_check_format (abfd, bfd_object)) | |
265 | { | |
266 | ctf_dprintf ("BFD format problem in %s: %s\n", | |
267 | filename ? filename : "(unknown file)", | |
268 | bfd_errmsg (bfd_get_error())); | |
269 | if (bfd_get_error() == bfd_error_file_ambiguously_recognized) | |
270 | return (ctf_set_open_errno (errp, ECTF_BFD_AMBIGUOUS)); | |
271 | else | |
272 | return (ctf_set_open_errno (errp, ECTF_FMT)); | |
273 | } | |
274 | ||
275 | if ((arci = ctf_bfdopen (abfd, errp)) == NULL) | |
276 | { | |
277 | if (!bfd_close_all_done (abfd)) | |
278 | ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); | |
279 | return NULL; /* errno is set for us. */ | |
280 | } | |
281 | arci->ctfi_bfd_close = ctf_bfdclose; | |
282 | arci->ctfi_abfd = abfd; | |
283 | ||
284 | return arci; | |
285 | } | |
286 | ||
287 | /* Open the specified file and return a pointer to a CTF container. The file | |
288 | can be either an ELF file or raw CTF file. This is just a convenient | |
289 | wrapper around ctf_fdopen() for callers. */ | |
290 | ||
291 | ctf_archive_t * | |
292 | ctf_open (const char *filename, const char *target, int *errp) | |
293 | { | |
294 | ctf_archive_t *arc; | |
295 | int fd; | |
296 | ||
297 | if ((fd = open (filename, O_RDONLY)) == -1) | |
298 | { | |
299 | if (errp != NULL) | |
300 | *errp = errno; | |
301 | return NULL; | |
302 | } | |
303 | ||
304 | arc = ctf_fdopen (fd, filename, target, errp); | |
305 | (void) close (fd); | |
306 | return arc; | |
307 | } | |
308 | ||
309 | /* Public entry point: open a CTF archive, or CTF file. Returns the archive, or | |
310 | NULL and an error in *err. Despite the fact that this uses CTF archives, it | |
311 | must be in this file to avoid dragging in BFD into non-BFD-using programs. */ | |
312 | ctf_archive_t * | |
313 | ctf_arc_open (const char *filename, int *errp) | |
314 | { | |
315 | return ctf_open (filename, NULL, errp); | |
316 | } |