1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <sys/types.h>
28 #include <sys/stat.h>
29 #include <sys/mman.h>
30 #include <ctf_impl.h>
31 #include <unistd.h>
32 #include <fcntl.h>
33 #include <errno.h>
34 #include <dlfcn.h>
35 #include <gelf.h>
36
37 #ifdef _LP64
38 static const char *_libctf_zlib = "/usr/lib/64/libz.so.1";
39 #else
40 static const char *_libctf_zlib = "/usr/lib/libz.so.1";
41 #endif
42
43 static struct {
44 int (*z_uncompress)(uchar_t *, ulong_t *, const uchar_t *, ulong_t);
45 const char *(*z_error)(int);
46 void *z_dlp;
47 } zlib;
48
49 static size_t _PAGESIZE;
50 static size_t _PAGEMASK;
51
52 #pragma init(_libctf_init)
53 void
54 _libctf_init(void)
55 {
56 const char *p = getenv("LIBCTF_DECOMPRESSOR");
57
58 if (p != NULL)
59 _libctf_zlib = p; /* use alternate decompression library */
60
61 _libctf_debug = getenv("LIBCTF_DEBUG") != NULL;
62
63 _PAGESIZE = getpagesize();
64 _PAGEMASK = ~(_PAGESIZE - 1);
65 }
66
67 /*
68 * Attempt to dlopen the decompression library and locate the symbols of
69 * interest that we will need to call. This information in cached so
70 * that multiple calls to ctf_bufopen() do not need to reopen the library.
71 */
72 void *
73 ctf_zopen(int *errp)
74 {
75 ctf_dprintf("decompressing CTF data using %s\n", _libctf_zlib);
76
77 if (zlib.z_dlp != NULL)
78 return (zlib.z_dlp); /* library is already loaded */
79
80 if (access(_libctf_zlib, R_OK) == -1)
81 return (ctf_set_open_errno(errp, ECTF_ZMISSING));
82
83 if ((zlib.z_dlp = dlopen(_libctf_zlib, RTLD_LAZY | RTLD_LOCAL)) == NULL)
84 return (ctf_set_open_errno(errp, ECTF_ZINIT));
85
86 zlib.z_uncompress = (int (*)()) dlsym(zlib.z_dlp, "uncompress");
87 zlib.z_error = (const char *(*)()) dlsym(zlib.z_dlp, "zError");
88
89 if (zlib.z_uncompress == NULL || zlib.z_error == NULL) {
90 (void) dlclose(zlib.z_dlp);
91 bzero(&zlib, sizeof (zlib));
92 return (ctf_set_open_errno(errp, ECTF_ZINIT));
93 }
94
95 return (zlib.z_dlp);
96 }
97
98 /*
99 * The ctf_bufopen() routine calls these subroutines, defined by <sys/zmod.h>,
100 * which we then patch through to the functions in the decompression library.
101 */
102 int
103 z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen)
104 {
105 return (zlib.z_uncompress(dst, (ulong_t *)dstlen, src, srclen));
106 }
107
108 const char *
109 z_strerror(int err)
110 {
111 return (zlib.z_error(err));
112 }
113
114 /*
115 * Convert a 32-bit ELF file header into GElf.
116 */
117 static void
118 ehdr_to_gelf(const Elf32_Ehdr *src, GElf_Ehdr *dst)
119 {
120 bcopy(src->e_ident, dst->e_ident, EI_NIDENT);
121 dst->e_type = src->e_type;
122 dst->e_machine = src->e_machine;
123 dst->e_version = src->e_version;
124 dst->e_entry = (Elf64_Addr)src->e_entry;
125 dst->e_phoff = (Elf64_Off)src->e_phoff;
126 dst->e_shoff = (Elf64_Off)src->e_shoff;
127 dst->e_flags = src->e_flags;
128 dst->e_ehsize = src->e_ehsize;
129 dst->e_phentsize = src->e_phentsize;
130 dst->e_phnum = src->e_phnum;
131 dst->e_shentsize = src->e_shentsize;
132 dst->e_shnum = src->e_shnum;
133 dst->e_shstrndx = src->e_shstrndx;
134 }
135
136 /*
137 * Convert a 32-bit ELF section header into GElf.
138 */
139 static void
140 shdr_to_gelf(const Elf32_Shdr *src, GElf_Shdr *dst)
141 {
142 dst->sh_name = src->sh_name;
143 dst->sh_type = src->sh_type;
144 dst->sh_flags = src->sh_flags;
145 dst->sh_addr = src->sh_addr;
146 dst->sh_offset = src->sh_offset;
147 dst->sh_size = src->sh_size;
148 dst->sh_link = src->sh_link;
149 dst->sh_info = src->sh_info;
150 dst->sh_addralign = src->sh_addralign;
151 dst->sh_entsize = src->sh_entsize;
152 }
153
154 /*
155 * In order to mmap a section from the ELF file, we must round down sh_offset
156 * to the previous page boundary, and mmap the surrounding page. We store
157 * the pointer to the start of the actual section data back into sp->cts_data.
158 */
159 const void *
160 ctf_sect_mmap(ctf_sect_t *sp, int fd)
161 {
162 size_t pageoff = sp->cts_offset & ~_PAGEMASK;
163
164 caddr_t base = mmap64(NULL, sp->cts_size + pageoff, PROT_READ,
165 MAP_PRIVATE, fd, sp->cts_offset & _PAGEMASK);
166
167 if (base != MAP_FAILED)
168 sp->cts_data = base + pageoff;
169
170 return (base);
171 }
172
173 /*
174 * Since sp->cts_data has the adjusted offset, we have to again round down
175 * to get the actual mmap address and round up to get the size.
176 */
177 void
178 ctf_sect_munmap(const ctf_sect_t *sp)
179 {
180 uintptr_t addr = (uintptr_t)sp->cts_data;
181 uintptr_t pageoff = addr & ~_PAGEMASK;
182
183 (void) munmap((void *)(addr - pageoff), sp->cts_size + pageoff);
184 }
185
186 /*
187 * Open the specified file descriptor and return a pointer to a CTF container.
188 * The file can be either an ELF file or raw CTF file. The caller is
189 * responsible for closing the file descriptor when it is no longer needed.
190 */
191 ctf_file_t *
192 ctf_fdopen(int fd, int *errp)
193 {
194 ctf_sect_t ctfsect, symsect, strsect;
195 ctf_file_t *fp = NULL;
196
197 struct stat64 st;
198 ssize_t nbytes;
199
200 union {
201 ctf_preamble_t ctf;
202 Elf32_Ehdr e32;
203 GElf_Ehdr e64;
204 } hdr;
205
206 bzero(&ctfsect, sizeof (ctf_sect_t));
207 bzero(&symsect, sizeof (ctf_sect_t));
208 bzero(&strsect, sizeof (ctf_sect_t));
209 bzero(&hdr.ctf, sizeof (hdr));
210
211 if (fstat64(fd, &st) == -1)
212 return (ctf_set_open_errno(errp, errno));
213
214 if ((nbytes = pread64(fd, &hdr.ctf, sizeof (hdr), 0)) <= 0)
215 return (ctf_set_open_errno(errp, nbytes < 0? errno : ECTF_FMT));
216
217 /*
218 * If we have read enough bytes to form a CTF header and the magic
219 * string matches, attempt to interpret the file as raw CTF.
220 */
221 if (nbytes >= sizeof (ctf_preamble_t) &&
222 hdr.ctf.ctp_magic == CTF_MAGIC) {
223 if (hdr.ctf.ctp_version > CTF_VERSION)
224 return (ctf_set_open_errno(errp, ECTF_CTFVERS));
225
226 ctfsect.cts_data = mmap64(NULL, st.st_size, PROT_READ,
227 MAP_PRIVATE, fd, 0);
228
229 if (ctfsect.cts_data == MAP_FAILED)
230 return (ctf_set_open_errno(errp, errno));
231
232 ctfsect.cts_name = _CTF_SECTION;
233 ctfsect.cts_type = SHT_PROGBITS;
234 ctfsect.cts_flags = SHF_ALLOC;
235 ctfsect.cts_size = (size_t)st.st_size;
236 ctfsect.cts_entsize = 1;
237 ctfsect.cts_offset = 0;
238
239 if ((fp = ctf_bufopen(&ctfsect, NULL, NULL, errp)) == NULL)
240 ctf_sect_munmap(&ctfsect);
241
242 return (fp);
243 }
244
245 /*
246 * If we have read enough bytes to form an ELF header and the magic
247 * string matches, attempt to interpret the file as an ELF file. We
248 * do our own largefile ELF processing, and convert everything to
249 * GElf structures so that clients can operate on any data model.
250 */
251 if (nbytes >= sizeof (Elf32_Ehdr) &&
252 bcmp(&hdr.e32.e_ident[EI_MAG0], ELFMAG, SELFMAG) == 0) {
253 #ifdef _BIG_ENDIAN
254 uchar_t order = ELFDATA2MSB;
255 #else
256 uchar_t order = ELFDATA2LSB;
257 #endif
258 GElf_Half i, n;
259 GElf_Shdr *sp;
260
261 void *strs_map;
262 size_t strs_mapsz;
263 const char *strs;
264
265 if (hdr.e32.e_ident[EI_DATA] != order)
266 return (ctf_set_open_errno(errp, ECTF_ENDIAN));
267 if (hdr.e32.e_version != EV_CURRENT)
268 return (ctf_set_open_errno(errp, ECTF_ELFVERS));
269
270 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS64) {
271 if (nbytes < sizeof (GElf_Ehdr))
272 return (ctf_set_open_errno(errp, ECTF_FMT));
273 } else {
274 Elf32_Ehdr e32 = hdr.e32;
275 ehdr_to_gelf(&e32, &hdr.e64);
276 }
277
278 if (hdr.e64.e_shstrndx >= hdr.e64.e_shnum)
279 return (ctf_set_open_errno(errp, ECTF_CORRUPT));
280
281 n = hdr.e64.e_shnum;
282 nbytes = sizeof (GElf_Shdr) * n;
283
284 if ((sp = malloc(nbytes)) == NULL)
285 return (ctf_set_open_errno(errp, errno));
286
287 /*
288 * Read in and convert to GElf the array of Shdr structures
289 * from e_shoff so we can locate sections of interest.
290 */
291 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) {
292 Elf32_Shdr *sp32;
293
294 nbytes = sizeof (Elf32_Shdr) * n;
295
296 if ((sp32 = malloc(nbytes)) == NULL || pread64(fd,
297 sp32, nbytes, hdr.e64.e_shoff) != nbytes) {
298 free(sp);
299 return (ctf_set_open_errno(errp, errno));
300 }
301
302 for (i = 0; i < n; i++)
303 shdr_to_gelf(&sp32[i], &sp[i]);
304
305 free(sp32);
306
307 } else if (pread64(fd, sp, nbytes, hdr.e64.e_shoff) != nbytes) {
308 free(sp);
309 return (ctf_set_open_errno(errp, errno));
310 }
311
312 /*
313 * Now mmap the section header strings section so that we can
314 * perform string comparison on the section names.
315 */
316 strs_mapsz = sp[hdr.e64.e_shstrndx].sh_size +
317 (sp[hdr.e64.e_shstrndx].sh_offset & ~_PAGEMASK);
318
319 strs_map = mmap64(NULL, strs_mapsz, PROT_READ, MAP_PRIVATE,
320 fd, sp[hdr.e64.e_shstrndx].sh_offset & _PAGEMASK);
321
322 strs = (const char *)strs_map +
323 (sp[hdr.e64.e_shstrndx].sh_offset & ~_PAGEMASK);
324
325 if (strs_map == MAP_FAILED) {
326 free(sp);
327 return (ctf_set_open_errno(errp, ECTF_MMAP));
328 }
329
330 /*
331 * Iterate over the section header array looking for the CTF
332 * section and symbol table. The strtab is linked to symtab.
333 */
334 for (i = 0; i < n; i++) {
335 const GElf_Shdr *shp = &sp[i];
336 const GElf_Shdr *lhp = &sp[shp->sh_link];
337
338 if (shp->sh_link >= hdr.e64.e_shnum)
339 continue; /* corrupt sh_link field */
340
341 if (shp->sh_name >= sp[hdr.e64.e_shstrndx].sh_size ||
342 lhp->sh_name >= sp[hdr.e64.e_shstrndx].sh_size)
343 continue; /* corrupt sh_name field */
344
345 if (shp->sh_type == SHT_PROGBITS &&
346 strcmp(strs + shp->sh_name, _CTF_SECTION) == 0) {
347 ctfsect.cts_name = strs + shp->sh_name;
348 ctfsect.cts_type = shp->sh_type;
349 ctfsect.cts_flags = shp->sh_flags;
350 ctfsect.cts_size = shp->sh_size;
351 ctfsect.cts_entsize = shp->sh_entsize;
352 ctfsect.cts_offset = (off64_t)shp->sh_offset;
353
354 } else if (shp->sh_type == SHT_SYMTAB) {
355 symsect.cts_name = strs + shp->sh_name;
356 symsect.cts_type = shp->sh_type;
357 symsect.cts_flags = shp->sh_flags;
358 symsect.cts_size = shp->sh_size;
359 symsect.cts_entsize = shp->sh_entsize;
360 symsect.cts_offset = (off64_t)shp->sh_offset;
361
362 strsect.cts_name = strs + lhp->sh_name;
363 strsect.cts_type = lhp->sh_type;
364 strsect.cts_flags = lhp->sh_flags;
365 strsect.cts_size = lhp->sh_size;
366 strsect.cts_entsize = lhp->sh_entsize;
367 strsect.cts_offset = (off64_t)lhp->sh_offset;
368 }
369 }
370
371 free(sp); /* free section header array */
372
373 if (ctfsect.cts_type == SHT_NULL) {
374 (void) munmap(strs_map, strs_mapsz);
375 return (ctf_set_open_errno(errp, ECTF_NOCTFDATA));
376 }
377
378 /*
379 * Now mmap the CTF data, symtab, and strtab sections and
380 * call ctf_bufopen() to do the rest of the work.
381 */
382 if (ctf_sect_mmap(&ctfsect, fd) == MAP_FAILED) {
383 (void) munmap(strs_map, strs_mapsz);
384 return (ctf_set_open_errno(errp, ECTF_MMAP));
385 }
386
387 if (symsect.cts_type != SHT_NULL &&
388 strsect.cts_type != SHT_NULL) {
389 if (ctf_sect_mmap(&symsect, fd) == MAP_FAILED ||
390 ctf_sect_mmap(&strsect, fd) == MAP_FAILED) {
391 (void) ctf_set_open_errno(errp, ECTF_MMAP);
392 goto bad; /* unmap all and abort */
393 }
394 fp = ctf_bufopen(&ctfsect, &symsect, &strsect, errp);
395 } else
396 fp = ctf_bufopen(&ctfsect, NULL, NULL, errp);
397 bad:
398 if (fp == NULL) {
399 ctf_sect_munmap(&ctfsect);
400 ctf_sect_munmap(&symsect);
401 ctf_sect_munmap(&strsect);
402 } else
403 fp->ctf_flags |= LCTF_MMAP;
404
405 (void) munmap(strs_map, strs_mapsz);
406 return (fp);
407 }
408
409 return (ctf_set_open_errno(errp, ECTF_FMT));
410 }
411
412 /*
413 * Open the specified file and return a pointer to a CTF container. The file
414 * can be either an ELF file or raw CTF file. This is just a convenient
415 * wrapper around ctf_fdopen() for callers.
416 */
417 ctf_file_t *
418 ctf_open(const char *filename, int *errp)
419 {
420 ctf_file_t *fp;
421 int fd;
422
423 if ((fd = open64(filename, O_RDONLY)) == -1) {
424 if (errp != NULL)
425 *errp = errno;
426 return (NULL);
427 }
428
429 fp = ctf_fdopen(fd, errp);
430 (void) close(fd);
431 return (fp);
432 }
433
434 /*
435 * Write the uncompressed CTF data stream to the specified file descriptor.
436 * This is useful for saving the results of dynamic CTF containers.
437 */
438 int
439 ctf_write(ctf_file_t *fp, int fd)
440 {
441 const uchar_t *buf = fp->ctf_base;
442 ssize_t resid = fp->ctf_size;
443 ssize_t len;
444
445 while (resid != 0) {
446 if ((len = write(fd, buf, resid)) <= 0)
447 return (ctf_set_errno(fp, errno));
448 resid -= len;
449 buf += len;
450 }
451
452 return (0);
453 }
454
455 /*
456 * Set the CTF library client version to the specified version. If version is
457 * zero, we just return the default library version number.
458 */
459 int
460 ctf_version(int version)
461 {
462 if (version < 0) {
463 errno = EINVAL;
464 return (-1);
465 }
466
467 if (version > 0) {
468 if (version > CTF_VERSION) {
469 errno = ENOTSUP;
470 return (-1);
471 }
472 ctf_dprintf("ctf_version: client using version %d\n", version);
473 _libctf_version = version;
474 }
475
476 return (_libctf_version);
477 }