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 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #if HAVE_NBTOOL_CONFIG_H
30 # include "nbtool_config.h"
31 #endif
32
33 #include <sys/types.h>
34 #include <sys/stat.h>
35 #include <sys/mman.h>
36 #include <sys/zmod.h>
37 #include <ctf_impl.h>
38 #include <unistd.h>
39 #include <fcntl.h>
40 #include <errno.h>
41 #ifdef illumos
42 #include <dlfcn.h>
43 #else
44 #include <zlib.h>
45 #endif
46 #include <gelf.h>
47
48 #ifdef illumos
49 #ifdef _LP64
50 static const char *_libctf_zlib = "/usr/lib/64/libz.so";
51 #else
52 static const char *_libctf_zlib = "/usr/lib/libz.so";
53 #endif
54 #endif
55
56 static struct {
57 int (*z_uncompress)(uchar_t *, ulong_t *, const uchar_t *, ulong_t);
58 const char *(*z_error)(int);
59 void *z_dlp;
60 } zlib;
61
62 static size_t _PAGESIZE;
63 static size_t _PAGEMASK;
64
65 #ifdef illumos
66 #pragma init(_libctf_init)
67 #else
68 void _libctf_init(void) __attribute__ ((constructor));
69 #endif
70 void
_libctf_init(void)71 _libctf_init(void)
72 {
73 #ifdef illumos
74 const char *p = getenv("LIBCTF_DECOMPRESSOR");
75
76 if (p != NULL)
77 _libctf_zlib = p; /* use alternate decompression library */
78 #endif
79
80 _libctf_debug = getenv("LIBCTF_DEBUG") != NULL;
81
82 _PAGESIZE = getpagesize();
83 _PAGEMASK = ~(_PAGESIZE - 1);
84 }
85
86 /*
87 * Attempt to dlopen the decompression library and locate the symbols of
88 * interest that we will need to call. This information in cached so
89 * that multiple calls to ctf_bufopen() do not need to reopen the library.
90 */
91 void *
ctf_zopen(int * errp)92 ctf_zopen(int *errp)
93 {
94 #ifdef illumos
95 ctf_dprintf("decompressing CTF data using %s\n", _libctf_zlib);
96
97 if (zlib.z_dlp != NULL)
98 return (zlib.z_dlp); /* library is already loaded */
99
100 if (access(_libctf_zlib, R_OK) == -1)
101 return (ctf_set_open_errno(errp, ECTF_ZMISSING));
102
103 if ((zlib.z_dlp = dlopen(_libctf_zlib, RTLD_LAZY | RTLD_LOCAL)) == NULL)
104 return (ctf_set_open_errno(errp, ECTF_ZINIT));
105
106 zlib.z_uncompress = (int (*)(uchar_t *, ulong_t *, const uchar_t *, ulong_t)) dlsym(zlib.z_dlp, "uncompress");
107 zlib.z_error = (const char *(*)(int)) dlsym(zlib.z_dlp, "zError");
108
109 if (zlib.z_uncompress == NULL || zlib.z_error == NULL) {
110 (void) dlclose(zlib.z_dlp);
111 bzero(&zlib, sizeof (zlib));
112 return (ctf_set_open_errno(errp, ECTF_ZINIT));
113 }
114 #else
115 zlib.z_uncompress = uncompress;
116 zlib.z_error = zError;
117
118 /* Dummy return variable as 'no error' */
119 zlib.z_dlp = (void *) (uintptr_t) 1;
120 #endif
121
122 return (zlib.z_dlp);
123 }
124
125 /*
126 * The ctf_bufopen() routine calls these subroutines, defined by <sys/zmod.h>,
127 * which we then patch through to the functions in the decompression library.
128 */
129 int
z_uncompress(void * dst,size_t * dstlen,const void * src,size_t srclen)130 z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen)
131 {
132 return (zlib.z_uncompress(dst, (ulong_t *)dstlen, src, srclen));
133 }
134
135 const char *
z_strerror(int err)136 z_strerror(int err)
137 {
138 return (zlib.z_error(err));
139 }
140
141 /*
142 * Convert a 32-bit ELF file header into GElf.
143 */
144 static void
ehdr_to_gelf(const Elf32_Ehdr * src,GElf_Ehdr * dst)145 ehdr_to_gelf(const Elf32_Ehdr *src, GElf_Ehdr *dst)
146 {
147 bcopy(src->e_ident, dst->e_ident, EI_NIDENT);
148 dst->e_type = src->e_type;
149 dst->e_machine = src->e_machine;
150 dst->e_version = src->e_version;
151 dst->e_entry = (Elf64_Addr)src->e_entry;
152 dst->e_phoff = (Elf64_Off)src->e_phoff;
153 dst->e_shoff = (Elf64_Off)src->e_shoff;
154 dst->e_flags = src->e_flags;
155 dst->e_ehsize = src->e_ehsize;
156 dst->e_phentsize = src->e_phentsize;
157 dst->e_phnum = src->e_phnum;
158 dst->e_shentsize = src->e_shentsize;
159 dst->e_shnum = src->e_shnum;
160 dst->e_shstrndx = src->e_shstrndx;
161 }
162
163 /*
164 * Convert a 32-bit ELF section header into GElf.
165 */
166 static void
shdr_to_gelf(const Elf32_Shdr * src,GElf_Shdr * dst)167 shdr_to_gelf(const Elf32_Shdr *src, GElf_Shdr *dst)
168 {
169 dst->sh_name = src->sh_name;
170 dst->sh_type = src->sh_type;
171 dst->sh_flags = src->sh_flags;
172 dst->sh_addr = src->sh_addr;
173 dst->sh_offset = src->sh_offset;
174 dst->sh_size = src->sh_size;
175 dst->sh_link = src->sh_link;
176 dst->sh_info = src->sh_info;
177 dst->sh_addralign = src->sh_addralign;
178 dst->sh_entsize = src->sh_entsize;
179 }
180
181 /*
182 * In order to mmap a section from the ELF file, we must round down sh_offset
183 * to the previous page boundary, and mmap the surrounding page. We store
184 * the pointer to the start of the actual section data back into sp->cts_data.
185 */
186 const void *
ctf_sect_mmap(ctf_sect_t * sp,int fd)187 ctf_sect_mmap(ctf_sect_t *sp, int fd)
188 {
189 size_t pageoff = sp->cts_offset & ~_PAGEMASK;
190
191 caddr_t base = mmap64(NULL, sp->cts_size + pageoff, PROT_READ,
192 MAP_PRIVATE, fd, sp->cts_offset & _PAGEMASK);
193
194 if (base != MAP_FAILED)
195 sp->cts_data = base + pageoff;
196
197 return (base);
198 }
199
200 /*
201 * Since sp->cts_data has the adjusted offset, we have to again round down
202 * to get the actual mmap address and round up to get the size.
203 */
204 void
ctf_sect_munmap(const ctf_sect_t * sp)205 ctf_sect_munmap(const ctf_sect_t *sp)
206 {
207 uintptr_t addr = (uintptr_t)sp->cts_data;
208 uintptr_t pageoff = addr & ~_PAGEMASK;
209
210 (void) munmap((void *)(addr - pageoff), sp->cts_size + pageoff);
211 }
212
213 /*
214 * Open the specified file descriptor and return a pointer to a CTF container.
215 * The file can be either an ELF file or raw CTF file. The caller is
216 * responsible for closing the file descriptor when it is no longer needed.
217 */
218 ctf_file_t *
ctf_fdopen(int fd,int * errp)219 ctf_fdopen(int fd, int *errp)
220 {
221 ctf_sect_t ctfsect, symsect, strsect;
222 ctf_file_t *fp = NULL;
223 size_t shstrndx, shnum;
224
225 struct stat64 st;
226 ssize_t nbytes;
227
228 union {
229 ctf_preamble_t ctf;
230 Elf32_Ehdr e32;
231 GElf_Ehdr e64;
232 } hdr;
233
234 bzero(&ctfsect, sizeof (ctf_sect_t));
235 bzero(&symsect, sizeof (ctf_sect_t));
236 bzero(&strsect, sizeof (ctf_sect_t));
237 bzero(&hdr, sizeof (hdr));
238
239 if (fstat64(fd, &st) == -1)
240 return (ctf_set_open_errno(errp, errno));
241
242 if ((nbytes = pread64(fd, &hdr, sizeof (hdr), 0)) <= 0)
243 return (ctf_set_open_errno(errp, nbytes < 0? errno : ECTF_FMT));
244
245 /*
246 * If we have read enough bytes to form a CTF header and the magic
247 * string matches, attempt to interpret the file as raw CTF.
248 */
249 if (nbytes >= (ssize_t) sizeof (ctf_preamble_t) &&
250 hdr.ctf.ctp_magic == CTF_MAGIC) {
251 if (hdr.ctf.ctp_version != CTF_VERSION_2 &&
252 hdr.ctf.ctp_version != CTF_VERSION_3)
253 return (ctf_set_open_errno(errp, ECTF_CTFVERS));
254
255 ctfsect.cts_data = mmap64(NULL, st.st_size, PROT_READ,
256 MAP_PRIVATE, fd, 0);
257
258 if (ctfsect.cts_data == MAP_FAILED)
259 return (ctf_set_open_errno(errp, errno));
260
261 ctfsect.cts_name = _CTF_SECTION;
262 ctfsect.cts_type = SHT_PROGBITS;
263 ctfsect.cts_flags = SHF_ALLOC;
264 ctfsect.cts_size = (size_t)st.st_size;
265 ctfsect.cts_entsize = 1;
266 ctfsect.cts_offset = 0;
267
268 if ((fp = ctf_bufopen(&ctfsect, NULL, NULL, errp)) == NULL)
269 ctf_sect_munmap(&ctfsect);
270
271 return (fp);
272 }
273
274 /*
275 * If we have read enough bytes to form an ELF header and the magic
276 * string matches, attempt to interpret the file as an ELF file. We
277 * do our own largefile ELF processing, and convert everything to
278 * GElf structures so that clients can operate on any data model.
279 */
280 if (nbytes >= (ssize_t) sizeof (Elf32_Ehdr) &&
281 bcmp(&hdr.e32.e_ident[EI_MAG0], ELFMAG, SELFMAG) == 0) {
282 #if BYTE_ORDER == _BIG_ENDIAN
283 uchar_t order = ELFDATA2MSB;
284 #else
285 uchar_t order = ELFDATA2LSB;
286 #endif
287 GElf_Shdr *sp;
288
289 void *strs_map;
290 size_t strs_mapsz, i;
291 char *strs;
292
293 if (hdr.e32.e_ident[EI_DATA] != order)
294 return (ctf_set_open_errno(errp, ECTF_ENDIAN));
295 if (hdr.e32.e_version != EV_CURRENT)
296 return (ctf_set_open_errno(errp, ECTF_ELFVERS));
297
298 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS64) {
299 if (nbytes < (ssize_t) sizeof (GElf_Ehdr))
300 return (ctf_set_open_errno(errp, ECTF_FMT));
301 } else {
302 Elf32_Ehdr e32 = hdr.e32;
303 ehdr_to_gelf(&e32, &hdr.e64);
304 }
305
306 shnum = hdr.e64.e_shnum;
307 shstrndx = hdr.e64.e_shstrndx;
308
309 /* Extended ELF sections */
310 if ((shstrndx == SHN_XINDEX) || (shnum == 0)) {
311 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) {
312 Elf32_Shdr x32;
313
314 if (pread64(fd, &x32, sizeof (x32),
315 hdr.e64.e_shoff) != sizeof (x32))
316 return (ctf_set_open_errno(errp,
317 errno));
318
319 shnum = x32.sh_size;
320 shstrndx = x32.sh_link;
321 } else {
322 Elf64_Shdr x64;
323
324 if (pread64(fd, &x64, sizeof (x64),
325 hdr.e64.e_shoff) != sizeof (x64))
326 return (ctf_set_open_errno(errp,
327 errno));
328
329 shnum = x64.sh_size;
330 shstrndx = x64.sh_link;
331 }
332 }
333
334 if (shstrndx >= shnum)
335 return (ctf_set_open_errno(errp, ECTF_CORRUPT));
336
337 nbytes = sizeof (GElf_Shdr) * shnum;
338
339 if ((sp = malloc(nbytes)) == NULL)
340 return (ctf_set_open_errno(errp, errno));
341
342 /*
343 * Read in and convert to GElf the array of Shdr structures
344 * from e_shoff so we can locate sections of interest.
345 */
346 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) {
347 Elf32_Shdr *sp32;
348
349 nbytes = sizeof (Elf32_Shdr) * shnum;
350
351 if ((sp32 = malloc(nbytes)) == NULL || pread64(fd,
352 sp32, nbytes, hdr.e64.e_shoff) != nbytes) {
353 free(sp);
354 free(sp32);
355 return (ctf_set_open_errno(errp, errno));
356 }
357
358 for (i = 0; i < shnum; i++)
359 shdr_to_gelf(&sp32[i], &sp[i]);
360
361 free(sp32);
362
363 } else if (pread64(fd, sp, nbytes, hdr.e64.e_shoff) != nbytes) {
364 free(sp);
365 return (ctf_set_open_errno(errp, errno));
366 }
367
368 /*
369 * Now mmap the section header strings section so that we can
370 * perform string comparison on the section names.
371 */
372 strs_mapsz = sp[shstrndx].sh_size +
373 (sp[shstrndx].sh_offset & ~_PAGEMASK);
374
375 strs_map = mmap64(NULL, strs_mapsz, PROT_READ, MAP_PRIVATE,
376 fd, sp[shstrndx].sh_offset & _PAGEMASK);
377
378 if (strs_map == MAP_FAILED)
379 return (ctf_set_open_errno(errp, errno));
380
381 strs = (char *)strs_map +
382 (sp[shstrndx].sh_offset & ~_PAGEMASK);
383
384 if (strs_map == MAP_FAILED) {
385 free(sp);
386 return (ctf_set_open_errno(errp, ECTF_MMAP));
387 }
388
389 /*
390 * Iterate over the section header array looking for the CTF
391 * section and symbol table. The strtab is linked to symtab.
392 */
393 for (i = 0; i < shnum; i++) {
394 const GElf_Shdr *shp = &sp[i];
395 const GElf_Shdr *lhp = &sp[shp->sh_link];
396
397 if (shp->sh_link >= shnum)
398 continue; /* corrupt sh_link field */
399
400 if (shp->sh_name >= sp[shstrndx].sh_size ||
401 lhp->sh_name >= sp[shstrndx].sh_size)
402 continue; /* corrupt sh_name field */
403
404 if (shp->sh_type == SHT_PROGBITS &&
405 strcmp(strs + shp->sh_name, _CTF_SECTION) == 0) {
406 ctfsect.cts_name = strs + shp->sh_name;
407 ctfsect.cts_type = shp->sh_type;
408 ctfsect.cts_flags = shp->sh_flags;
409 ctfsect.cts_size = shp->sh_size;
410 ctfsect.cts_entsize = shp->sh_entsize;
411 ctfsect.cts_offset = (off64_t)shp->sh_offset;
412
413 } else if (shp->sh_type == SHT_SYMTAB) {
414 symsect.cts_name = strs + shp->sh_name;
415 symsect.cts_type = shp->sh_type;
416 symsect.cts_flags = shp->sh_flags;
417 symsect.cts_size = shp->sh_size;
418 symsect.cts_entsize = shp->sh_entsize;
419 symsect.cts_offset = (off64_t)shp->sh_offset;
420
421 strsect.cts_name = strs + lhp->sh_name;
422 strsect.cts_type = lhp->sh_type;
423 strsect.cts_flags = lhp->sh_flags;
424 strsect.cts_size = lhp->sh_size;
425 strsect.cts_entsize = lhp->sh_entsize;
426 strsect.cts_offset = (off64_t)lhp->sh_offset;
427 }
428 }
429
430 free(sp); /* free section header array */
431
432 if (ctfsect.cts_type == SHT_NULL) {
433 (void) munmap(strs_map, strs_mapsz);
434 return (ctf_set_open_errno(errp, ECTF_NOCTFDATA));
435 }
436
437 /*
438 * Now mmap the CTF data, symtab, and strtab sections and
439 * call ctf_bufopen() to do the rest of the work.
440 */
441 if (ctf_sect_mmap(&ctfsect, fd) == MAP_FAILED) {
442 (void) munmap(strs_map, strs_mapsz);
443 return (ctf_set_open_errno(errp, ECTF_MMAP));
444 }
445
446 if (symsect.cts_type != SHT_NULL &&
447 strsect.cts_type != SHT_NULL) {
448 if (ctf_sect_mmap(&symsect, fd) == MAP_FAILED ||
449 ctf_sect_mmap(&strsect, fd) == MAP_FAILED) {
450 (void) ctf_set_open_errno(errp, ECTF_MMAP);
451 goto bad; /* unmap all and abort */
452 }
453 fp = ctf_bufopen(&ctfsect, &symsect, &strsect, errp);
454 } else
455 fp = ctf_bufopen(&ctfsect, NULL, NULL, errp);
456 bad:
457 if (fp == NULL) {
458 ctf_sect_munmap(&ctfsect);
459 ctf_sect_munmap(&symsect);
460 ctf_sect_munmap(&strsect);
461 } else
462 fp->ctf_flags |= LCTF_MMAP;
463
464 (void) munmap(strs_map, strs_mapsz);
465 return (fp);
466 }
467
468 return (ctf_set_open_errno(errp, ECTF_FMT));
469 }
470
471 /*
472 * Open the specified file and return a pointer to a CTF container. The file
473 * can be either an ELF file or raw CTF file. This is just a convenient
474 * wrapper around ctf_fdopen() for callers.
475 */
476 ctf_file_t *
ctf_open(const char * filename,int * errp)477 ctf_open(const char *filename, int *errp)
478 {
479 ctf_file_t *fp;
480 int fd;
481
482 if ((fd = open64(filename, O_RDONLY)) == -1) {
483 if (errp != NULL)
484 *errp = errno;
485 return (NULL);
486 }
487
488 fp = ctf_fdopen(fd, errp);
489 (void) close(fd);
490 return (fp);
491 }
492
493 /*
494 * Write the uncompressed CTF data stream to the specified file descriptor.
495 * This is useful for saving the results of dynamic CTF containers.
496 */
497 int
ctf_write(ctf_file_t * fp,int fd)498 ctf_write(ctf_file_t *fp, int fd)
499 {
500 const uchar_t *buf = fp->ctf_base;
501 ssize_t resid = fp->ctf_size;
502 ssize_t len;
503
504 while (resid != 0) {
505 if ((len = write(fd, buf, resid)) <= 0)
506 return (ctf_set_errno(fp, errno));
507 resid -= len;
508 buf += len;
509 }
510
511 return (0);
512 }
513
514 /*
515 * Set the CTF library client version to the specified version. If version is
516 * zero, we just return the default library version number.
517 */
518 int
ctf_version(int version)519 ctf_version(int version)
520 {
521 if (version < 0) {
522 errno = EINVAL;
523 return (-1);
524 }
525
526 if (version > 0) {
527 if (version > CTF_VERSION) {
528 errno = ENOTSUP;
529 return (-1);
530 }
531 ctf_dprintf("ctf_version: client using version %d\n", version);
532 _libctf_version = version;
533 }
534
535 return (_libctf_version);
536 }
537