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