cddl/contrib/opensolaris/lib/libctf/common/ctf_lib.c

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