1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008 John Birrell <jb@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/ctf.h>
30 #include <sys/kdb.h>
31 #include <sys/linker.h>
32
33 #include <ddb/db_ctf.h>
34
35 /*
36 * Note this file is included by both link_elf.c and link_elf_obj.c.
37 */
38
39 #ifdef DDB_CTF
40 #include <contrib/zlib/zlib.h>
41 #endif
42
43 static int
link_elf_ctf_get(linker_file_t lf,linker_ctf_t * lc)44 link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
45 {
46 #ifdef DDB_CTF
47 Elf_Ehdr *hdr = NULL;
48 Elf_Shdr *shdr = NULL;
49 caddr_t ctftab = NULL;
50 caddr_t raw = NULL;
51 caddr_t shstrtab = NULL;
52 elf_file_t ef = (elf_file_t) lf;
53 int flags;
54 int i;
55 int nbytes;
56 size_t sz;
57 struct nameidata nd;
58 struct thread *td = curthread;
59 struct ctf_header cth;
60 #endif
61 int error = 0;
62
63 if (lf == NULL || lc == NULL)
64 return (EINVAL);
65
66 /* Set the defaults for no CTF present. That's not a crime! */
67 bzero(lc, sizeof(*lc));
68
69 #ifdef DDB_CTF
70 /*
71 * First check if we've tried to load CTF data previously and the
72 * CTF ELF section wasn't found. We flag that condition by setting
73 * ctfcnt to -1. See below.
74 */
75 if (ef->ctfcnt < 0)
76 return (EFTYPE);
77
78 /* Now check if we've already loaded the CTF data.. */
79 if (ef->ctfcnt > 0) {
80 /* We only need to load once. */
81 lc->ctftab = ef->ctftab;
82 lc->ctfcnt = ef->ctfcnt;
83 lc->symtab = ef->ddbsymtab;
84 lc->strtab = ef->ddbstrtab;
85 lc->strcnt = ef->ddbstrcnt;
86 lc->nsym = ef->ddbsymcnt;
87 lc->ctfoffp = (uint32_t **) &ef->ctfoff;
88 lc->typoffp = (uint32_t **) &ef->typoff;
89 lc->typlenp = &ef->typlen;
90 return (0);
91 }
92
93 if (panicstr != NULL || kdb_active)
94 return (ENXIO);
95
96 /*
97 * We need to try reading the CTF data. Flag no CTF data present
98 * by default and if we actually succeed in reading it, we'll
99 * update ctfcnt to the number of bytes read.
100 */
101 ef->ctfcnt = -1;
102
103 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, lf->pathname);
104 flags = FREAD;
105 error = vn_open(&nd, &flags, 0, NULL);
106 if (error)
107 return (error);
108 NDFREE_PNBUF(&nd);
109
110 /* Allocate memory for the FLF header. */
111 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
112
113 /* Read the ELF header. */
114 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr),
115 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL,
116 td)) != 0)
117 goto out;
118
119 /* Sanity check. */
120 if (!IS_ELF(*hdr)) {
121 error = ENOEXEC;
122 goto out;
123 }
124
125 nbytes = hdr->e_shnum * hdr->e_shentsize;
126 if (nbytes == 0 || hdr->e_shoff == 0 ||
127 hdr->e_shentsize != sizeof(Elf_Shdr)) {
128 error = ENOEXEC;
129 goto out;
130 }
131
132 /* Allocate memory for all the section headers */
133 shdr = malloc(nbytes, M_LINKER, M_WAITOK);
134
135 /* Read all the section headers */
136 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes,
137 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
138 NULL, td)) != 0)
139 goto out;
140
141 /*
142 * We need to search for the CTF section by name, so if the
143 * section names aren't present, then we can't locate the
144 * .SUNW_ctf section containing the CTF data.
145 */
146 if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
147 if (bootverbose) {
148 printf(
149 "%s(%d): module %s e_shstrndx is %d, sh_type is %d\n",
150 __func__, __LINE__, lf->pathname, hdr->e_shstrndx,
151 shdr[hdr->e_shstrndx].sh_type);
152 }
153 error = EFTYPE;
154 goto out;
155 }
156
157 /* Allocate memory to buffer the section header strings. */
158 shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER, M_WAITOK);
159
160 /* Read the section header strings. */
161 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab,
162 shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset,
163 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, td)) != 0)
164 goto out;
165
166 /* Search for the section containing the CTF data. */
167 for (i = 0; i < hdr->e_shnum; i++)
168 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0)
169 break;
170
171 /* Check if the CTF section wasn't found. */
172 if (i >= hdr->e_shnum) {
173 if (bootverbose) {
174 printf("%s(%d): module %s has no .SUNW_ctf section\n",
175 __func__, __LINE__, lf->pathname);
176 }
177 error = EFTYPE;
178 goto out;
179 }
180
181 /* Read the CTF header. */
182 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, &cth, sizeof(cth),
183 shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
184 NOCRED, NULL, td)) != 0)
185 goto out;
186
187 /* Check the CTF magic number. */
188 if (cth.cth_magic != CTF_MAGIC) {
189 if (bootverbose) {
190 printf("%s(%d): module %s has invalid format\n",
191 __func__, __LINE__, lf->pathname);
192 }
193 error = EFTYPE;
194 goto out;
195 }
196
197 if (cth.cth_version != CTF_VERSION_2 &&
198 cth.cth_version != CTF_VERSION_3) {
199 if (bootverbose) {
200 printf(
201 "%s(%d): module %s CTF format has unsupported version %d\n",
202 __func__, __LINE__, lf->pathname, cth.cth_version);
203 }
204 error = EFTYPE;
205 goto out;
206 }
207
208 /* Check if the data is compressed. */
209 if ((cth.cth_flags & CTF_F_COMPRESS) != 0) {
210 /*
211 * The last two fields in the CTF header are the offset
212 * from the end of the header to the start of the string
213 * data and the length of that string data. Use this
214 * information to determine the decompressed CTF data
215 * buffer required.
216 */
217 sz = cth.cth_stroff + cth.cth_strlen + sizeof(cth);
218
219 /*
220 * Allocate memory for the compressed CTF data, including
221 * the header (which isn't compressed).
222 */
223 raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
224 } else {
225 /*
226 * The CTF data is not compressed, so the ELF section
227 * size is the same as the buffer size required.
228 */
229 sz = shdr[i].sh_size;
230 }
231
232 /*
233 * Allocate memory to buffer the CTF data in its decompressed
234 * form.
235 */
236 ctftab = malloc(sz, M_LINKER, M_WAITOK);
237
238 /*
239 * Read the CTF data into the raw buffer if compressed, or
240 * directly into the CTF buffer otherwise.
241 */
242 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw,
243 shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
244 td->td_ucred, NOCRED, NULL, td)) != 0)
245 goto out;
246
247 /* Check if decompression is required. */
248 if (raw != NULL) {
249 uLongf destlen;
250 int ret;
251
252 /*
253 * The header isn't compressed, so copy that into the
254 * CTF buffer first.
255 */
256 bcopy(&cth, ctftab, sizeof(cth));
257
258 destlen = sz - sizeof(cth);
259 ret = uncompress(ctftab + sizeof(cth), &destlen,
260 raw + sizeof(cth), shdr[i].sh_size - sizeof(cth));
261 if (ret != Z_OK) {
262 if (bootverbose) {
263 printf("%s(%d): zlib uncompress returned %d\n",
264 __func__, __LINE__, ret);
265 }
266 error = EIO;
267 goto out;
268 }
269 }
270
271 /* Got the CTF data! */
272 ef->ctftab = ctftab;
273 ef->ctfcnt = shdr[i].sh_size;
274
275 /* We'll retain the memory allocated for the CTF data. */
276 ctftab = NULL;
277
278 /* Let the caller use the CTF data read. */
279 lc->ctftab = ef->ctftab;
280 lc->ctfcnt = ef->ctfcnt;
281 lc->symtab = ef->ddbsymtab;
282 lc->strtab = ef->ddbstrtab;
283 lc->strcnt = ef->ddbstrcnt;
284 lc->nsym = ef->ddbsymcnt;
285 lc->ctfoffp = (uint32_t **) &ef->ctfoff;
286 lc->typoffp = (uint32_t **) &ef->typoff;
287 lc->typlenp = &ef->typlen;
288
289 out:
290 VOP_UNLOCK(nd.ni_vp);
291 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
292
293 if (hdr != NULL)
294 free(hdr, M_LINKER);
295 if (shdr != NULL)
296 free(shdr, M_LINKER);
297 if (shstrtab != NULL)
298 free(shstrtab, M_LINKER);
299 if (ctftab != NULL)
300 free(ctftab, M_LINKER);
301 if (raw != NULL)
302 free(raw, M_LINKER);
303 #else
304 error = EOPNOTSUPP;
305 #endif
306
307 return (error);
308 }
309
310 static int
link_elf_ctf_get_ddb(linker_file_t lf,linker_ctf_t * lc)311 link_elf_ctf_get_ddb(linker_file_t lf, linker_ctf_t *lc)
312 {
313 elf_file_t ef = (elf_file_t)lf;
314
315 /*
316 * Check whether CTF data was loaded or if a
317 * previous loading attempt failed (ctfcnt == -1).
318 */
319 if (ef->ctfcnt <= 0) {
320 return (ENOENT);
321 }
322
323 lc->ctftab = ef->ctftab;
324 lc->ctfcnt = ef->ctfcnt;
325 lc->symtab = ef->ddbsymtab;
326 lc->strtab = ef->ddbstrtab;
327 lc->strcnt = ef->ddbstrcnt;
328 lc->nsym = ef->ddbsymcnt;
329
330 return (0);
331 }
332
333 static int
link_elf_ctf_lookup_typename(linker_file_t lf,linker_ctf_t * lc,const char * typename)334 link_elf_ctf_lookup_typename(linker_file_t lf, linker_ctf_t *lc,
335 const char *typename)
336 {
337 if (link_elf_ctf_get_ddb(lf, lc))
338 return (ENOENT);
339
340 #ifdef DDB
341 return (db_ctf_lookup_typename(lc, typename) ? 0 : ENOENT);
342 #else
343 return (ENOENT);
344 #endif
345 }
346