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