FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ctf.c
1 /*-
2 * Copyright (c) 2008 John Birrell <jb@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/10.0/sys/kern/kern_ctf.c 241896 2012-10-22 17:50:54Z kib $
27 */
28
29 /*
30 * Note this file is included by both link_elf.c and link_elf_obj.c.
31 *
32 * The CTF header structure definition can't be used here because it's
33 * (annoyingly) covered by the CDDL. We will just use a few bytes from
34 * it as an integer array where we 'know' what they mean.
35 */
36 #define CTF_HDR_SIZE 36
37 #define CTF_HDR_STRTAB_U32 7
38 #define CTF_HDR_STRLEN_U32 8
39
40 #ifdef DDB_CTF
41 static void *
42 z_alloc(void *nil, u_int items, u_int size)
43 {
44 void *ptr;
45
46 ptr = malloc(items * size, M_TEMP, M_NOWAIT);
47 return ptr;
48 }
49
50 static void
51 z_free(void *nil, void *ptr)
52 {
53 free(ptr, M_TEMP);
54 }
55
56 #endif
57
58 static int
59 link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
60 {
61 #ifdef DDB_CTF
62 Elf_Ehdr *hdr = NULL;
63 Elf_Shdr *shdr = NULL;
64 caddr_t ctftab = NULL;
65 caddr_t raw = NULL;
66 caddr_t shstrtab = NULL;
67 elf_file_t ef = (elf_file_t) lf;
68 int flags;
69 int i;
70 int nbytes;
71 ssize_t resid;
72 size_t sz;
73 struct nameidata nd;
74 struct thread *td = curthread;
75 uint8_t ctf_hdr[CTF_HDR_SIZE];
76 #endif
77 int error = 0;
78
79 if (lf == NULL || lc == NULL)
80 return (EINVAL);
81
82 /* Set the defaults for no CTF present. That's not a crime! */
83 bzero(lc, sizeof(*lc));
84
85 #ifdef DDB_CTF
86 /*
87 * First check if we've tried to load CTF data previously and the
88 * CTF ELF section wasn't found. We flag that condition by setting
89 * ctfcnt to -1. See below.
90 */
91 if (ef->ctfcnt < 0)
92 return (EFTYPE);
93
94 /* Now check if we've already loaded the CTF data.. */
95 if (ef->ctfcnt > 0) {
96 /* We only need to load once. */
97 lc->ctftab = ef->ctftab;
98 lc->ctfcnt = ef->ctfcnt;
99 lc->symtab = ef->ddbsymtab;
100 lc->strtab = ef->ddbstrtab;
101 lc->strcnt = ef->ddbstrcnt;
102 lc->nsym = ef->ddbsymcnt;
103 lc->ctfoffp = (uint32_t **) &ef->ctfoff;
104 lc->typoffp = (uint32_t **) &ef->typoff;
105 lc->typlenp = &ef->typlen;
106 return (0);
107 }
108
109 /*
110 * We need to try reading the CTF data. Flag no CTF data present
111 * by default and if we actually succeed in reading it, we'll
112 * update ctfcnt to the number of bytes read.
113 */
114 ef->ctfcnt = -1;
115
116 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, lf->pathname, td);
117 flags = FREAD;
118 error = vn_open(&nd, &flags, 0, NULL);
119 if (error)
120 return (error);
121 NDFREE(&nd, NDF_ONLY_PNBUF);
122
123 /* Allocate memory for the FLF header. */
124 if ((hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK)) == NULL) {
125 error = ENOMEM;
126 goto out;
127 }
128
129 /* Read the ELF header. */
130 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr),
131 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid,
132 td)) != 0)
133 goto out;
134
135 /* Sanity check. */
136 if (!IS_ELF(*hdr)) {
137 error = ENOEXEC;
138 goto out;
139 }
140
141 nbytes = hdr->e_shnum * hdr->e_shentsize;
142 if (nbytes == 0 || hdr->e_shoff == 0 ||
143 hdr->e_shentsize != sizeof(Elf_Shdr)) {
144 error = ENOEXEC;
145 goto out;
146 }
147
148 /* Allocate memory for all the section headers */
149 if ((shdr = malloc(nbytes, M_LINKER, M_WAITOK)) == NULL) {
150 error = ENOMEM;
151 goto out;
152 }
153
154 /* Read all the section headers */
155 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes,
156 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
157 &resid, td)) != 0)
158 goto out;
159
160 /*
161 * We need to search for the CTF section by name, so if the
162 * section names aren't present, then we can't locate the
163 * .SUNW_ctf section containing the CTF data.
164 */
165 if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
166 printf("%s(%d): module %s e_shstrndx is %d, sh_type is %d\n",
167 __func__, __LINE__, lf->pathname, hdr->e_shstrndx,
168 shdr[hdr->e_shstrndx].sh_type);
169 error = EFTYPE;
170 goto out;
171 }
172
173 /* Allocate memory to buffer the section header strings. */
174 if ((shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER,
175 M_WAITOK)) == NULL) {
176 error = ENOMEM;
177 goto out;
178 }
179
180 /* Read the section header strings. */
181 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab,
182 shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset,
183 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid,
184 td)) != 0)
185 goto out;
186
187 /* Search for the section containing the CTF data. */
188 for (i = 0; i < hdr->e_shnum; i++)
189 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0)
190 break;
191
192 /* Check if the CTF section wasn't found. */
193 if (i >= hdr->e_shnum) {
194 printf("%s(%d): module %s has no .SUNW_ctf section\n",
195 __func__, __LINE__, lf->pathname);
196 error = EFTYPE;
197 goto out;
198 }
199
200 /* Read the CTF header. */
201 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, ctf_hdr, sizeof(ctf_hdr),
202 shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
203 NOCRED, &resid, td)) != 0)
204 goto out;
205
206 /* Check the CTF magic number. (XXX check for big endian!) */
207 if (ctf_hdr[0] != 0xf1 || ctf_hdr[1] != 0xcf) {
208 printf("%s(%d): module %s has invalid format\n",
209 __func__, __LINE__, lf->pathname);
210 error = EFTYPE;
211 goto out;
212 }
213
214 /* Check if version 2. */
215 if (ctf_hdr[2] != 2) {
216 printf("%s(%d): module %s CTF format version is %d "
217 "(2 expected)\n",
218 __func__, __LINE__, lf->pathname, ctf_hdr[2]);
219 error = EFTYPE;
220 goto out;
221 }
222
223 /* Check if the data is compressed. */
224 if ((ctf_hdr[3] & 0x1) != 0) {
225 uint32_t *u32 = (uint32_t *) ctf_hdr;
226
227 /*
228 * The last two fields in the CTF header are the offset
229 * from the end of the header to the start of the string
230 * data and the length of that string data. se this
231 * information to determine the decompressed CTF data
232 * buffer required.
233 */
234 sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] +
235 sizeof(ctf_hdr);
236
237 /*
238 * Allocate memory for the compressed CTF data, including
239 * the header (which isn't compressed).
240 */
241 if ((raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK)) == NULL) {
242 error = ENOMEM;
243 goto out;
244 }
245 } else {
246 /*
247 * The CTF data is not compressed, so the ELF section
248 * size is the same as the buffer size required.
249 */
250 sz = shdr[i].sh_size;
251 }
252
253 /*
254 * Allocate memory to buffer the CTF data in it's decompressed
255 * form.
256 */
257 if ((ctftab = malloc(sz, M_LINKER, M_WAITOK)) == NULL) {
258 error = ENOMEM;
259 goto out;
260 }
261
262 /*
263 * Read the CTF data into the raw buffer if compressed, or
264 * directly into the CTF buffer otherwise.
265 */
266 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw,
267 shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
268 td->td_ucred, NOCRED, &resid, td)) != 0)
269 goto out;
270
271 /* Check if decompression is required. */
272 if (raw != NULL) {
273 z_stream zs;
274 int ret;
275
276 /*
277 * The header isn't compressed, so copy that into the
278 * CTF buffer first.
279 */
280 bcopy(ctf_hdr, ctftab, sizeof(ctf_hdr));
281
282 /* Initialise the zlib structure. */
283 bzero(&zs, sizeof(zs));
284 zs.zalloc = z_alloc;
285 zs.zfree = z_free;
286
287 if (inflateInit(&zs) != Z_OK) {
288 error = EIO;
289 goto out;
290 }
291
292 zs.avail_in = shdr[i].sh_size - sizeof(ctf_hdr);
293 zs.next_in = ((uint8_t *) raw) + sizeof(ctf_hdr);
294 zs.avail_out = sz - sizeof(ctf_hdr);
295 zs.next_out = ((uint8_t *) ctftab) + sizeof(ctf_hdr);
296 if ((ret = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
297 printf("%s(%d): zlib inflate returned %d\n", __func__, __LINE__, ret);
298 error = EIO;
299 goto out;
300 }
301 }
302
303 /* Got the CTF data! */
304 ef->ctftab = ctftab;
305 ef->ctfcnt = shdr[i].sh_size;
306
307 /* We'll retain the memory allocated for the CTF data. */
308 ctftab = NULL;
309
310 /* Let the caller use the CTF data read. */
311 lc->ctftab = ef->ctftab;
312 lc->ctfcnt = ef->ctfcnt;
313 lc->symtab = ef->ddbsymtab;
314 lc->strtab = ef->ddbstrtab;
315 lc->strcnt = ef->ddbstrcnt;
316 lc->nsym = ef->ddbsymcnt;
317 lc->ctfoffp = (uint32_t **) &ef->ctfoff;
318 lc->typoffp = (uint32_t **) &ef->typoff;
319 lc->typlenp = &ef->typlen;
320
321 out:
322 VOP_UNLOCK(nd.ni_vp, 0);
323 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
324
325 if (hdr != NULL)
326 free(hdr, M_LINKER);
327 if (shdr != NULL)
328 free(shdr, M_LINKER);
329 if (shstrtab != NULL)
330 free(shstrtab, M_LINKER);
331 if (ctftab != NULL)
332 free(ctftab, M_LINKER);
333 if (raw != NULL)
334 free(raw, M_LINKER);
335 #else
336 error = EOPNOTSUPP;
337 #endif
338
339 return (error);
340 }
Cache object: bfcc0e0aa029601dc7639669ac27072c
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