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/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 #if defined(sun)
  38 #include <dlfcn.h>
  39 #else
  40 #include <zlib.h>
  41 #endif
  42 #include <gelf.h>
  43
  44 #if defined(sun)
  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 #if defined(sun)
  62 #pragma init(_libctf_init)
  63 #else
  64 void    _libctf_init(void) __attribute__ ((constructor));
  65 #endif
  66 void
  67 _libctf_init(void)
  68 {
  69 #if defined(sun)
  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 *
  88 ctf_zopen(int *errp)
  89 {
  90 #if defined(sun)
  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
 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 *
 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
 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
 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 *
 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
 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 *
 215 ctf_fdopen(int fd, int *errp)
 216 {
 217         ctf_sect_t ctfsect, symsect, strsect;
 218         ctf_file_t *fp = NULL;
 219
 220         struct stat64 st;
 221         ssize_t nbytes;
 222
 223         union {
 224                 ctf_preamble_t ctf;
 225                 Elf32_Ehdr e32;
 226                 GElf_Ehdr e64;
 227         } hdr;
 228
 229         bzero(&ctfsect, sizeof (ctf_sect_t));
 230         bzero(&symsect, sizeof (ctf_sect_t));
 231         bzero(&strsect, sizeof (ctf_sect_t));
 232         bzero(&hdr.ctf, sizeof (hdr));
 233
 234         if (fstat64(fd, &st) == -1)
 235                 return (ctf_set_open_errno(errp, errno));
 236
 237         if ((nbytes = pread64(fd, &hdr.ctf, sizeof (hdr), 0)) <= 0)
 238                 return (ctf_set_open_errno(errp, nbytes < 0? errno : ECTF_FMT));
 239
 240         /*
 241          * If we have read enough bytes to form a CTF header and the magic
 242          * string matches, attempt to interpret the file as raw CTF.
 243          */
 244         if (nbytes >= (ssize_t) sizeof (ctf_preamble_t) &&
 245             hdr.ctf.ctp_magic == CTF_MAGIC) {
 246                 if (hdr.ctf.ctp_version > CTF_VERSION)
 247                         return (ctf_set_open_errno(errp, ECTF_CTFVERS));
 248
 249                 ctfsect.cts_data = mmap64(NULL, st.st_size, PROT_READ,
 250                     MAP_PRIVATE, fd, 0);
 251
 252                 if (ctfsect.cts_data == MAP_FAILED)
 253                         return (ctf_set_open_errno(errp, errno));
 254
 255                 ctfsect.cts_name = _CTF_SECTION;
 256                 ctfsect.cts_type = SHT_PROGBITS;
 257                 ctfsect.cts_flags = SHF_ALLOC;
 258                 ctfsect.cts_size = (size_t)st.st_size;
 259                 ctfsect.cts_entsize = 1;
 260                 ctfsect.cts_offset = 0;
 261
 262                 if ((fp = ctf_bufopen(&ctfsect, NULL, NULL, errp)) == NULL)
 263                         ctf_sect_munmap(&ctfsect);
 264
 265                 return (fp);
 266         }
 267
 268         /*
 269          * If we have read enough bytes to form an ELF header and the magic
 270          * string matches, attempt to interpret the file as an ELF file.  We
 271          * do our own largefile ELF processing, and convert everything to
 272          * GElf structures so that clients can operate on any data model.
 273          */
 274         if (nbytes >= (ssize_t) sizeof (Elf32_Ehdr) &&
 275             bcmp(&hdr.e32.e_ident[EI_MAG0], ELFMAG, SELFMAG) == 0) {
 276 #ifdef  _BIG_ENDIAN
 277                 uchar_t order = ELFDATA2MSB;
 278 #else
 279                 uchar_t order = ELFDATA2LSB;
 280 #endif
 281                 GElf_Half i, n;
 282                 GElf_Shdr *sp;
 283
 284                 void *strs_map;
 285                 size_t strs_mapsz;
 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                 if (hdr.e64.e_shstrndx >= hdr.e64.e_shnum)
 302                         return (ctf_set_open_errno(errp, ECTF_CORRUPT));
 303
 304                 n = hdr.e64.e_shnum;
 305                 nbytes = sizeof (GElf_Shdr) * n;
 306
 307                 if ((sp = malloc(nbytes)) == NULL)
 308                         return (ctf_set_open_errno(errp, errno));
 309
 310                 /*
 311                  * Read in and convert to GElf the array of Shdr structures
 312                  * from e_shoff so we can locate sections of interest.
 313                  */
 314                 if (hdr.e32.e_ident[EI_CLASS] == ELFCLASS32) {
 315                         Elf32_Shdr *sp32;
 316
 317                         nbytes = sizeof (Elf32_Shdr) * n;
 318
 319                         if ((sp32 = malloc(nbytes)) == NULL || pread64(fd,
 320                             sp32, nbytes, hdr.e64.e_shoff) != nbytes) {
 321                                 free(sp);
 322                                 return (ctf_set_open_errno(errp, errno));
 323                         }
 324
 325                         for (i = 0; i < n; i++)
 326                                 shdr_to_gelf(&sp32[i], &sp[i]);
 327
 328                         free(sp32);
 329
 330                 } else if (pread64(fd, sp, nbytes, hdr.e64.e_shoff) != nbytes) {
 331                         free(sp);
 332                         return (ctf_set_open_errno(errp, errno));
 333                 }
 334
 335                 /*
 336                  * Now mmap the section header strings section so that we can
 337                  * perform string comparison on the section names.
 338                  */
 339                 strs_mapsz = sp[hdr.e64.e_shstrndx].sh_size +
 340                     (sp[hdr.e64.e_shstrndx].sh_offset & ~_PAGEMASK);
 341
 342                 strs_map = mmap64(NULL, strs_mapsz, PROT_READ, MAP_PRIVATE,
 343                     fd, sp[hdr.e64.e_shstrndx].sh_offset & _PAGEMASK);
 344
 345                 strs = (char *)strs_map +
 346                     (sp[hdr.e64.e_shstrndx].sh_offset & ~_PAGEMASK);
 347
 348                 if (strs_map == MAP_FAILED) {
 349                         free(sp);
 350                         return (ctf_set_open_errno(errp, ECTF_MMAP));
 351                 }
 352
 353                 /*
 354                  * Iterate over the section header array looking for the CTF
 355                  * section and symbol table.  The strtab is linked to symtab.
 356                  */
 357                 for (i = 0; i < n; i++) {
 358                         const GElf_Shdr *shp = &sp[i];
 359                         const GElf_Shdr *lhp = &sp[shp->sh_link];
 360
 361                         if (shp->sh_link >= hdr.e64.e_shnum)
 362                                 continue; /* corrupt sh_link field */
 363
 364                         if (shp->sh_name >= sp[hdr.e64.e_shstrndx].sh_size ||
 365                             lhp->sh_name >= sp[hdr.e64.e_shstrndx].sh_size)
 366                                 continue; /* corrupt sh_name field */
 367
 368                         if (shp->sh_type == SHT_PROGBITS &&
 369                             strcmp(strs + shp->sh_name, _CTF_SECTION) == 0) {
 370                                 ctfsect.cts_name = strs + shp->sh_name;
 371                                 ctfsect.cts_type = shp->sh_type;
 372                                 ctfsect.cts_flags = shp->sh_flags;
 373                                 ctfsect.cts_size = shp->sh_size;
 374                                 ctfsect.cts_entsize = shp->sh_entsize;
 375                                 ctfsect.cts_offset = (off64_t)shp->sh_offset;
 376
 377                         } else if (shp->sh_type == SHT_SYMTAB) {
 378                                 symsect.cts_name = strs + shp->sh_name;
 379                                 symsect.cts_type = shp->sh_type;
 380                                 symsect.cts_flags = shp->sh_flags;
 381                                 symsect.cts_size = shp->sh_size;
 382                                 symsect.cts_entsize = shp->sh_entsize;
 383                                 symsect.cts_offset = (off64_t)shp->sh_offset;
 384
 385                                 strsect.cts_name = strs + lhp->sh_name;
 386                                 strsect.cts_type = lhp->sh_type;
 387                                 strsect.cts_flags = lhp->sh_flags;
 388                                 strsect.cts_size = lhp->sh_size;
 389                                 strsect.cts_entsize = lhp->sh_entsize;
 390                                 strsect.cts_offset = (off64_t)lhp->sh_offset;
 391                         }
 392                 }
 393
 394                 free(sp); /* free section header array */
 395
 396                 if (ctfsect.cts_type == SHT_NULL) {
 397                         (void) munmap(strs_map, strs_mapsz);
 398                         return (ctf_set_open_errno(errp, ECTF_NOCTFDATA));
 399                 }
 400
 401                 /*
 402                  * Now mmap the CTF data, symtab, and strtab sections and
 403                  * call ctf_bufopen() to do the rest of the work.
 404                  */
 405                 if (ctf_sect_mmap(&ctfsect, fd) == MAP_FAILED) {
 406                         (void) munmap(strs_map, strs_mapsz);
 407                         return (ctf_set_open_errno(errp, ECTF_MMAP));
 408                 }
 409
 410                 if (symsect.cts_type != SHT_NULL &&
 411                     strsect.cts_type != SHT_NULL) {
 412                         if (ctf_sect_mmap(&symsect, fd) == MAP_FAILED ||
 413                             ctf_sect_mmap(&strsect, fd) == MAP_FAILED) {
 414                                 (void) ctf_set_open_errno(errp, ECTF_MMAP);
 415                                 goto bad; /* unmap all and abort */
 416                         }
 417                         fp = ctf_bufopen(&ctfsect, &symsect, &strsect, errp);
 418                 } else
 419                         fp = ctf_bufopen(&ctfsect, NULL, NULL, errp);
 420 bad:
 421                 if (fp == NULL) {
 422                         ctf_sect_munmap(&ctfsect);
 423                         ctf_sect_munmap(&symsect);
 424                         ctf_sect_munmap(&strsect);
 425                 } else
 426                         fp->ctf_flags |= LCTF_MMAP;
 427
 428                 (void) munmap(strs_map, strs_mapsz);
 429                 return (fp);
 430         }
 431
 432         return (ctf_set_open_errno(errp, ECTF_FMT));
 433 }
 434
 435 /*
 436  * Open the specified file and return a pointer to a CTF container.  The file
 437  * can be either an ELF file or raw CTF file.  This is just a convenient
 438  * wrapper around ctf_fdopen() for callers.
 439  */
 440 ctf_file_t *
 441 ctf_open(const char *filename, int *errp)
 442 {
 443         ctf_file_t *fp;
 444         int fd;
 445
 446         if ((fd = open64(filename, O_RDONLY)) == -1) {
 447                 if (errp != NULL)
 448                         *errp = errno;
 449                 return (NULL);
 450         }
 451
 452         fp = ctf_fdopen(fd, errp);
 453         (void) close(fd);
 454         return (fp);
 455 }
 456
 457 /*
 458  * Write the uncompressed CTF data stream to the specified file descriptor.
 459  * This is useful for saving the results of dynamic CTF containers.
 460  */
 461 int
 462 ctf_write(ctf_file_t *fp, int fd)
 463 {
 464         const uchar_t *buf = fp->ctf_base;
 465         ssize_t resid = fp->ctf_size;
 466         ssize_t len;
 467
 468         while (resid != 0) {
 469                 if ((len = write(fd, buf, resid)) <= 0)
 470                         return (ctf_set_errno(fp, errno));
 471                 resid -= len;
 472                 buf += len;
 473         }
 474
 475         return (0);
 476 }
 477
 478 /*
 479  * Set the CTF library client version to the specified version.  If version is
 480  * zero, we just return the default library version number.
 481  */
 482 int
 483 ctf_version(int version)
 484 {
 485         if (version < 0) {
 486                 errno = EINVAL;
 487                 return (-1);
 488         }
 489
 490         if (version > 0) {
 491                 if (version > CTF_VERSION) {
 492                         errno = ENOTSUP;
 493                         return (-1);
 494                 }
 495                 ctf_dprintf("ctf_version: client using version %d\n", version);
 496                 _libctf_version = version;
 497         }
 498
 499         return (_libctf_version);
 500 }