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
43static int
44link_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
289out:
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
310static int
311link_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
333static int
334link_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