binutils/strings.c

   1 /* strings -- print the strings of printable characters in files
   2    Copyright (C) 1993-2017 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  17    02110-1301, USA.  */
  18 \f
  19 /* Usage: strings [options] file...
  20
  21    Options:
  22    --all
  23    -a
  24    -            Scan each file in its entirety.
  25
  26    --data
  27    -d           Scan only the initialized data section(s) of object files.
  28
  29    --print-file-name
  30    -f           Print the name of the file before each string.
  31
  32    --bytes=min-len
  33    -n min-len
  34    -min-len     Print graphic char sequences, MIN-LEN or more bytes long,
  35                 that are followed by a NUL or a newline.  Default is 4.
  36
  37    --radix={o,x,d}
  38    -t {o,x,d}   Print the offset within the file before each string,
  39                 in octal/hex/decimal.
  40
  41   --include-all-whitespace
  42   -w            By default tab and space are the only whitepace included in graphic
  43                 char sequences.  This option considers all of isspace() valid.
  44
  45    -o           Like -to.  (Some other implementations have -o like -to,
  46                 others like -td.  We chose one arbitrarily.)
  47
  48    --encoding={s,S,b,l,B,L}
  49    -e {s,S,b,l,B,L}
  50                 Select character encoding: 7-bit-character, 8-bit-character,
  51                 bigendian 16-bit, littleendian 16-bit, bigendian 32-bit,
  52                 littleendian 32-bit.
  53
  54    --target=BFDNAME
  55    -T {bfdname}
  56                 Specify a non-default object file format.
  57
  58   --output-separator=sep_string
  59   -s sep_string String used to separate parsed strings in output.
  60                 Default is newline.
  61
  62    --help
  63    -h           Print the usage message on the standard output.
  64
  65    --version
  66    -V
  67    -v           Print the program version number.
  68
  69    Written by Richard Stallman <rms@gnu.ai.mit.edu>
  70    and David MacKenzie <djm@gnu.ai.mit.edu>.  */
  71
  72 #include "sysdep.h"
  73 #include "bfd.h"
  74 #include "getopt.h"
  75 #include "libiberty.h"
  76 #include "safe-ctype.h"
  77 #include "bucomm.h"
  78
  79 #define STRING_ISGRAPHIC(c) \
  80       (   (c) >= 0 \
  81        && (c) <= 255 \
  82        && ((c) == '\t' || ISPRINT (c) || (encoding == 'S' && (c) > 127) \
  83            || (include_all_whitespace && ISSPACE (c))) \
  84       )
  85
  86 #ifndef errno
  87 extern int errno;
  88 #endif
  89
  90 /* The BFD section flags that identify an initialized data section.  */
  91 #define DATA_FLAGS (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS)
  92
  93 /* Radix for printing addresses (must be 8, 10 or 16).  */
  94 static int address_radix;
  95
  96 /* Minimum length of sequence of graphic chars to trigger output.  */
  97 static int string_min;
  98
  99 /* Whether or not we include all whitespace as a graphic char.   */
 100 static bfd_boolean include_all_whitespace;
 101
 102 /* TRUE means print address within file for each string.  */
 103 static bfd_boolean print_addresses;
 104
 105 /* TRUE means print filename for each string.  */
 106 static bfd_boolean print_filenames;
 107
 108 /* TRUE means for object files scan only the data section.  */
 109 static bfd_boolean datasection_only;
 110
 111 /* TRUE if we found an initialized data section in the current file.  */
 112 static bfd_boolean got_a_section;
 113
 114 /* The BFD object file format.  */
 115 static char *target;
 116
 117 /* The character encoding format.  */
 118 static char encoding;
 119 static int encoding_bytes;
 120
 121 /* Output string used to separate parsed strings  */
 122 static char *output_separator;
 123
 124 static struct option long_options[] =
 125 {
 126   {"all", no_argument, NULL, 'a'},
 127   {"data", no_argument, NULL, 'd'},
 128   {"print-file-name", no_argument, NULL, 'f'},
 129   {"bytes", required_argument, NULL, 'n'},
 130   {"radix", required_argument, NULL, 't'},
 131   {"include-all-whitespace", required_argument, NULL, 'w'},
 132   {"encoding", required_argument, NULL, 'e'},
 133   {"target", required_argument, NULL, 'T'},
 134   {"output-separator", required_argument, NULL, 's'},
 135   {"help", no_argument, NULL, 'h'},
 136   {"version", no_argument, NULL, 'v'},
 137   {NULL, 0, NULL, 0}
 138 };
 139
 140 /* Records the size of a named file so that we
 141    do not repeatedly run bfd_stat() on it.  */
 142
 143 typedef struct
 144 {
 145   const char *  filename;
 146   bfd_size_type filesize;
 147 } filename_and_size_t;
 148
 149 static bfd_boolean strings_file (char *);
 150 static void print_strings (const char *, FILE *, file_ptr, int, int, char *);
 151 static void usage (FILE *, int) ATTRIBUTE_NORETURN;
 152 \f
 153 int main (int, char **);
 154
 155 int
 156 main (int argc, char **argv)
 157 {
 158   int optc;
 159   int exit_status = 0;
 160   bfd_boolean files_given = FALSE;
 161   char *s;
 162   int numeric_opt = 0;
 163
 164 #if defined (HAVE_SETLOCALE)
 165   setlocale (LC_ALL, "");
 166 #endif
 167   bindtextdomain (PACKAGE, LOCALEDIR);
 168   textdomain (PACKAGE);
 169
 170   program_name = argv[0];
 171   xmalloc_set_program_name (program_name);
 172   bfd_set_error_program_name (program_name);
 173
 174   expandargv (&argc, &argv);
 175
 176   string_min = 4;
 177   include_all_whitespace = FALSE;
 178   print_addresses = FALSE;
 179   print_filenames = FALSE;
 180   if (DEFAULT_STRINGS_ALL)
 181     datasection_only = FALSE;
 182   else
 183     datasection_only = TRUE;
 184   target = NULL;
 185   encoding = 's';
 186   output_separator = NULL;
 187
 188   while ((optc = getopt_long (argc, argv, "adfhHn:wot:e:T:s:Vv0123456789",
 189                               long_options, (int *) 0)) != EOF)
 190     {
 191       switch (optc)
 192         {
 193         case 'a':
 194           datasection_only = FALSE;
 195           break;
 196
 197         case 'd':
 198           datasection_only = TRUE;
 199           break;
 200
 201         case 'f':
 202           print_filenames = TRUE;
 203           break;
 204
 205         case 'H':
 206         case 'h':
 207           usage (stdout, 0);
 208
 209         case 'n':
 210           string_min = (int) strtoul (optarg, &s, 0);
 211           if (s != NULL && *s != 0)
 212             fatal (_("invalid integer argument %s"), optarg);
 213           break;
 214
 215         case 'w':
 216           include_all_whitespace = TRUE;
 217           break;
 218
 219         case 'o':
 220           print_addresses = TRUE;
 221           address_radix = 8;
 222           break;
 223
 224         case 't':
 225           print_addresses = TRUE;
 226           if (optarg[1] != '\0')
 227             usage (stderr, 1);
 228           switch (optarg[0])
 229             {
 230             case 'o':
 231               address_radix = 8;
 232               break;
 233
 234             case 'd':
 235               address_radix = 10;
 236               break;
 237
 238             case 'x':
 239               address_radix = 16;
 240               break;
 241
 242             default:
 243               usage (stderr, 1);
 244             }
 245           break;
 246
 247         case 'T':
 248           target = optarg;
 249           break;
 250
 251         case 'e':
 252           if (optarg[1] != '\0')
 253             usage (stderr, 1);
 254           encoding = optarg[0];
 255           break;
 256
 257         case 's':
 258           output_separator = optarg;
 259           break;
 260
 261         case 'V':
 262         case 'v':
 263           print_version ("strings");
 264           break;
 265
 266         case '?':
 267           usage (stderr, 1);
 268
 269         default:
 270           numeric_opt = optind;
 271           break;
 272         }
 273     }
 274
 275   if (numeric_opt != 0)
 276     {
 277       string_min = (int) strtoul (argv[numeric_opt - 1] + 1, &s, 0);
 278       if (s != NULL && *s != 0)
 279         fatal (_("invalid integer argument %s"), argv[numeric_opt - 1] + 1);
 280     }
 281   if (string_min < 1)
 282     fatal (_("invalid minimum string length %d"), string_min);
 283
 284   switch (encoding)
 285     {
 286     case 'S':
 287     case 's':
 288       encoding_bytes = 1;
 289       break;
 290     case 'b':
 291     case 'l':
 292       encoding_bytes = 2;
 293       break;
 294     case 'B':
 295     case 'L':
 296       encoding_bytes = 4;
 297       break;
 298     default:
 299       usage (stderr, 1);
 300     }
 301
 302   bfd_init ();
 303   set_default_bfd_target ();
 304
 305   if (optind >= argc)
 306     {
 307       datasection_only = FALSE;
 308       SET_BINARY (fileno (stdin));
 309       print_strings ("{standard input}", stdin, 0, 0, 0, (char *) NULL);
 310       files_given = TRUE;
 311     }
 312   else
 313     {
 314       for (; optind < argc; ++optind)
 315         {
 316           if (strcmp (argv[optind], "-") == 0)
 317             datasection_only = FALSE;
 318           else
 319             {
 320               files_given = TRUE;
 321               exit_status |= !strings_file (argv[optind]);
 322             }
 323         }
 324     }
 325
 326   if (!files_given)
 327     usage (stderr, 1);
 328
 329   return (exit_status);
 330 }
 331 \f
 332 /* Scan section SECT of the file ABFD, whose printable name is in
 333    ARG->filename and whose size might be in ARG->filesize.  If it
 334    contains initialized data set `got_a_section' and print the
 335    strings in it.
 336
 337    FIXME: We ought to be able to return error codes/messages for
 338    certain conditions.  */
 339
 340 static void
 341 strings_a_section (bfd *abfd, asection *sect, void *arg)
 342 {
 343   filename_and_size_t * filename_and_sizep;
 344   bfd_size_type *filesizep;
 345   bfd_size_type sectsize;
 346   void *mem;
 347
 348   if ((sect->flags & DATA_FLAGS) != DATA_FLAGS)
 349     return;
 350
 351   sectsize = bfd_get_section_size (sect);
 352
 353   if (sectsize <= 0)
 354     return;
 355
 356   /* Get the size of the file.  This might have been cached for us.  */
 357   filename_and_sizep = (filename_and_size_t *) arg;
 358   filesizep = & filename_and_sizep->filesize;
 359
 360   if (*filesizep == 0)
 361     {
 362       struct stat st;
 363
 364       if (bfd_stat (abfd, &st))
 365         return;
 366
 367       /* Cache the result so that we do not repeatedly stat this file.  */
 368       *filesizep = st.st_size;
 369     }
 370
 371   /* Compare the size of the section against the size of the file.
 372      If the section is bigger then the file must be corrupt and
 373      we should not try dumping it.  */
 374   if (sectsize >= *filesizep)
 375     return;
 376
 377   mem = xmalloc (sectsize);
 378
 379   if (bfd_get_section_contents (abfd, sect, mem, (file_ptr) 0, sectsize))
 380     {
 381       got_a_section = TRUE;
 382
 383       print_strings (filename_and_sizep->filename, NULL, sect->filepos,
 384                      0, sectsize, (char *) mem);
 385     }
 386
 387   free (mem);
 388 }
 389
 390 /* Scan all of the sections in FILE, and print the strings
 391    in the initialized data section(s).
 392
 393    Return TRUE if successful,
 394    FALSE if not (such as if FILE is not an object file).  */
 395
 396 static bfd_boolean
 397 strings_object_file (const char *file)
 398 {
 399   filename_and_size_t filename_and_size;
 400   bfd *abfd;
 401
 402   abfd = bfd_openr (file, target);
 403
 404   if (abfd == NULL)
 405     /* Treat the file as a non-object file.  */
 406     return FALSE;
 407
 408   /* This call is mainly for its side effect of reading in the sections.
 409      We follow the traditional behavior of `strings' in that we don't
 410      complain if we don't recognize a file to be an object file.  */
 411   if (!bfd_check_format (abfd, bfd_object))
 412     {
 413       bfd_close (abfd);
 414       return FALSE;
 415     }
 416
 417   got_a_section = FALSE;
 418   filename_and_size.filename = file;
 419   filename_and_size.filesize = 0;
 420   bfd_map_over_sections (abfd, strings_a_section, & filename_and_size);
 421
 422   if (!bfd_close (abfd))
 423     {
 424       bfd_nonfatal (file);
 425       return FALSE;
 426     }
 427
 428   return got_a_section;
 429 }
 430
 431 /* Print the strings in FILE.  Return TRUE if ok, FALSE if an error occurs.  */
 432
 433 static bfd_boolean
 434 strings_file (char *file)
 435 {
 436   struct stat st;
 437
 438   /* get_file_size does not support non-S_ISREG files.  */
 439
 440   if (stat (file, &st) < 0)
 441     {
 442       if (errno == ENOENT)
 443         non_fatal (_("'%s': No such file"), file);
 444       else
 445         non_fatal (_("Warning: could not locate '%s'.  reason: %s"),
 446                    file, strerror (errno));
 447       return FALSE;
 448     }
 449
 450   /* If we weren't told to scan the whole file,
 451      try to open it as an object file and only look at
 452      initialized data sections.  If that fails, fall back to the
 453      whole file.  */
 454   if (!datasection_only || !strings_object_file (file))
 455     {
 456       FILE *stream;
 457
 458       stream = fopen (file, FOPEN_RB);
 459       if (stream == NULL)
 460         {
 461           fprintf (stderr, "%s: ", program_name);
 462           perror (file);
 463           return FALSE;
 464         }
 465
 466       print_strings (file, stream, (file_ptr) 0, 0, 0, (char *) 0);
 467
 468       if (fclose (stream) == EOF)
 469         {
 470           fprintf (stderr, "%s: ", program_name);
 471           perror (file);
 472           return FALSE;
 473         }
 474     }
 475
 476   return TRUE;
 477 }
 478 \f
 479 /* Read the next character, return EOF if none available.
 480    Assume that STREAM is positioned so that the next byte read
 481    is at address ADDRESS in the file.
 482
 483    If STREAM is NULL, do not read from it.
 484    The caller can supply a buffer of characters
 485    to be processed before the data in STREAM.
 486    MAGIC is the address of the buffer and
 487    MAGICCOUNT is how many characters are in it.  */
 488
 489 static long
 490 get_char (FILE *stream, file_ptr *address, int *magiccount, char **magic)
 491 {
 492   int c, i;
 493   long r = 0;
 494
 495   for (i = 0; i < encoding_bytes; i++)
 496     {
 497       if (*magiccount)
 498         {
 499           (*magiccount)--;
 500           c = *(*magic)++;
 501         }
 502       else
 503         {
 504           if (stream == NULL)
 505             return EOF;
 506
 507           /* Only use getc_unlocked if we found a declaration for it.
 508              Otherwise, libc is not thread safe by default, and we
 509              should not use it.  */
 510
 511 #if defined(HAVE_GETC_UNLOCKED) && HAVE_DECL_GETC_UNLOCKED
 512           c = getc_unlocked (stream);
 513 #else
 514           c = getc (stream);
 515 #endif
 516           if (c == EOF)
 517             return EOF;
 518         }
 519
 520       (*address)++;
 521       r = (r << 8) | (c & 0xff);
 522     }
 523
 524   switch (encoding)
 525     {
 526     default:
 527       break;
 528     case 'l':
 529       r = ((r & 0xff) << 8) | ((r & 0xff00) >> 8);
 530       break;
 531     case 'L':
 532       r = (((r & 0xff) << 24) | ((r & 0xff00) << 8)
 533            | ((r & 0xff0000) >> 8) | ((r & 0xff000000) >> 24));
 534       break;
 535     }
 536
 537   return r;
 538 }
 539 \f
 540 /* Find the strings in file FILENAME, read from STREAM.
 541    Assume that STREAM is positioned so that the next byte read
 542    is at address ADDRESS in the file.
 543    Stop reading at address STOP_POINT in the file, if nonzero.
 544
 545    If STREAM is NULL, do not read from it.
 546    The caller can supply a buffer of characters
 547    to be processed before the data in STREAM.
 548    MAGIC is the address of the buffer and
 549    MAGICCOUNT is how many characters are in it.
 550    Those characters come at address ADDRESS and the data in STREAM follow.  */
 551
 552 static void
 553 print_strings (const char *filename, FILE *stream, file_ptr address,
 554                int stop_point, int magiccount, char *magic)
 555 {
 556   char *buf = (char *) xmalloc (sizeof (char) * (string_min + 1));
 557
 558   while (1)
 559     {
 560       file_ptr start;
 561       int i;
 562       long c;
 563
 564       /* See if the next `string_min' chars are all graphic chars.  */
 565     tryline:
 566       if (stop_point && address >= stop_point)
 567         break;
 568       start = address;
 569       for (i = 0; i < string_min; i++)
 570         {
 571           c = get_char (stream, &address, &magiccount, &magic);
 572           if (c == EOF)
 573             {
 574               free (buf);
 575               return;
 576             }
 577           if (! STRING_ISGRAPHIC (c))
 578             /* Found a non-graphic.  Try again starting with next char.  */
 579             goto tryline;
 580           buf[i] = c;
 581         }
 582
 583       /* We found a run of `string_min' graphic characters.  Print up
 584          to the next non-graphic character.  */
 585
 586       if (print_filenames)
 587         printf ("%s: ", filename);
 588       if (print_addresses)
 589         switch (address_radix)
 590           {
 591           case 8:
 592 #ifdef HAVE_LONG_LONG
 593             if (sizeof (start) > sizeof (long))
 594               {
 595 # ifndef __MSVCRT__
 596                 printf ("%7llo ", (unsigned long long) start);
 597 # else
 598                 printf ("%7I64o ", (unsigned long long) start);
 599 # endif
 600               }
 601             else
 602 #elif !BFD_HOST_64BIT_LONG
 603             if (start != (unsigned long) start)
 604               printf ("++%7lo ", (unsigned long) start);
 605             else
 606 #endif
 607               printf ("%7lo ", (unsigned long) start);
 608             break;
 609
 610           case 10:
 611 #ifdef HAVE_LONG_LONG
 612             if (sizeof (start) > sizeof (long))
 613               {
 614 # ifndef __MSVCRT__
 615                 printf ("%7lld ", (unsigned long long) start);
 616 # else
 617                 printf ("%7I64d ", (unsigned long long) start);
 618 # endif
 619               }
 620             else
 621 #elif !BFD_HOST_64BIT_LONG
 622             if (start != (unsigned long) start)
 623               printf ("++%7ld ", (unsigned long) start);
 624             else
 625 #endif
 626               printf ("%7ld ", (long) start);
 627             break;
 628
 629           case 16:
 630 #ifdef HAVE_LONG_LONG
 631             if (sizeof (start) > sizeof (long))
 632               {
 633 # ifndef __MSVCRT__
 634                 printf ("%7llx ", (unsigned long long) start);
 635 # else
 636                 printf ("%7I64x ", (unsigned long long) start);
 637 # endif
 638               }
 639             else
 640 #elif !BFD_HOST_64BIT_LONG
 641             if (start != (unsigned long) start)
 642               printf ("%lx%8.8lx ", (unsigned long) (start >> 32),
 643                       (unsigned long) (start & 0xffffffff));
 644             else
 645 #endif
 646               printf ("%7lx ", (unsigned long) start);
 647             break;
 648           }
 649
 650       buf[i] = '\0';
 651       fputs (buf, stdout);
 652
 653       while (1)
 654         {
 655           c = get_char (stream, &address, &magiccount, &magic);
 656           if (c == EOF)
 657             break;
 658           if (! STRING_ISGRAPHIC (c))
 659             break;
 660           putchar (c);
 661         }
 662
 663       if (output_separator)
 664         fputs (output_separator, stdout);
 665       else
 666         putchar ('\n');
 667     }
 668   free (buf);
 669 }
 670 \f
 671 static void
 672 usage (FILE *stream, int status)
 673 {
 674   fprintf (stream, _("Usage: %s [option(s)] [file(s)]\n"), program_name);
 675   fprintf (stream, _(" Display printable strings in [file(s)] (stdin by default)\n"));
 676   fprintf (stream, _(" The options are:\n"));
 677
 678   if (DEFAULT_STRINGS_ALL)
 679     fprintf (stream, _("\
 680   -a - --all                Scan the entire file, not just the data section [default]\n\
 681   -d --data                 Only scan the data sections in the file\n"));
 682   else
 683     fprintf (stream, _("\
 684   -a - --all                Scan the entire file, not just the data section\n\
 685   -d --data                 Only scan the data sections in the file [default]\n"));
 686
 687   fprintf (stream, _("\
 688   -f --print-file-name      Print the name of the file before each string\n\
 689   -n --bytes=[number]       Locate & print any NUL-terminated sequence of at\n\
 690   -<number>                   least [number] characters (default 4).\n\
 691   -t --radix={o,d,x}        Print the location of the string in base 8, 10 or 16\n\
 692   -w --include-all-whitespace Include all whitespace as valid string characters\n\
 693   -o                        An alias for --radix=o\n\
 694   -T --target=<BFDNAME>     Specify the binary file format\n\
 695   -e --encoding={s,S,b,l,B,L} Select character size and endianness:\n\
 696                             s = 7-bit, S = 8-bit, {b,l} = 16-bit, {B,L} = 32-bit\n\
 697   -s --output-separator=<string> String used to separate strings in output.\n\
 698   @<file>                   Read options from <file>\n\
 699   -h --help                 Display this information\n\
 700   -v -V --version           Print the program's version number\n"));
 701   list_supported_targets (program_name, stream);
 702   if (REPORT_BUGS_TO[0] && status == 0)
 703     fprintf (stream, _("Report bugs to %s\n"), REPORT_BUGS_TO);
 704   exit (status);
 705 }