binutils/strings.c

   1 /* strings -- print the strings of printable characters in files
   2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
   3    2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012
   4    Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20 \f
  21 /* Usage: strings [options] file...
  22
  23    Options:
  24    --all
  25    -a
  26    -            Do not scan only the initialized data section of object files.
  27
  28    --print-file-name
  29    -f           Print the name of the file before each string.
  30
  31    --bytes=min-len
  32    -n min-len
  33    -min-len     Print graphic char sequences, MIN-LEN or more bytes long,
  34                 that are followed by a NUL or a newline.  Default is 4.
  35
  36    --radix={o,x,d}
  37    -t {o,x,d}   Print the offset within the file before each string,
  38                 in octal/hex/decimal.
  39
  40    -o           Like -to.  (Some other implementations have -o like -to,
  41                 others like -td.  We chose one arbitrarily.)
  42
  43    --encoding={s,S,b,l,B,L}
  44    -e {s,S,b,l,B,L}
  45                 Select character encoding: 7-bit-character, 8-bit-character,
  46                 bigendian 16-bit, littleendian 16-bit, bigendian 32-bit,
  47                 littleendian 32-bit.
  48
  49    --target=BFDNAME
  50    -T {bfdname}
  51                 Specify a non-default object file format.
  52
  53    --help
  54    -h           Print the usage message on the standard output.
  55
  56    --version
  57    -V
  58    -v           Print the program version number.
  59
  60    Written by Richard Stallman <rms@gnu.ai.mit.edu>
  61    and David MacKenzie <djm@gnu.ai.mit.edu>.  */
  62
  63 #include "sysdep.h"
  64 #include "bfd.h"
  65 #include "getopt.h"
  66 #include "libiberty.h"
  67 #include "safe-ctype.h"
  68 #include "bucomm.h"
  69
  70 #define STRING_ISGRAPHIC(c) \
  71       (   (c) >= 0 \
  72        && (c) <= 255 \
  73        && ((c) == '\t' || ISPRINT (c) || (encoding == 'S' && (c) > 127)))
  74
  75 #ifndef errno
  76 extern int errno;
  77 #endif
  78
  79 /* The BFD section flags that identify an initialized data section.  */
  80 #define DATA_FLAGS (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS)
  81
  82 /* Radix for printing addresses (must be 8, 10 or 16).  */
  83 static int address_radix;
  84
  85 /* Minimum length of sequence of graphic chars to trigger output.  */
  86 static int string_min;
  87
  88 /* TRUE means print address within file for each string.  */
  89 static bfd_boolean print_addresses;
  90
  91 /* TRUE means print filename for each string.  */
  92 static bfd_boolean print_filenames;
  93
  94 /* TRUE means for object files scan only the data section.  */
  95 static bfd_boolean datasection_only;
  96
  97 /* TRUE if we found an initialized data section in the current file.  */
  98 static bfd_boolean got_a_section;
  99
 100 /* The BFD object file format.  */
 101 static char *target;
 102
 103 /* The character encoding format.  */
 104 static char encoding;
 105 static int encoding_bytes;
 106
 107 static struct option long_options[] =
 108 {
 109   {"all", no_argument, NULL, 'a'},
 110   {"print-file-name", no_argument, NULL, 'f'},
 111   {"bytes", required_argument, NULL, 'n'},
 112   {"radix", required_argument, NULL, 't'},
 113   {"encoding", required_argument, NULL, 'e'},
 114   {"target", required_argument, NULL, 'T'},
 115   {"help", no_argument, NULL, 'h'},
 116   {"version", no_argument, NULL, 'v'},
 117   {NULL, 0, NULL, 0}
 118 };
 119
 120 /* Records the size of a named file so that we
 121    do not repeatedly run bfd_stat() on it.  */
 122
 123 typedef struct
 124 {
 125   const char *  filename;
 126   bfd_size_type filesize;
 127 } filename_and_size_t;
 128
 129 static void strings_a_section (bfd *, asection *, void *);
 130 static bfd_boolean strings_object_file (const char *);
 131 static bfd_boolean strings_file (char *file);
 132 static void print_strings (const char *, FILE *, file_ptr, int, int, char *);
 133 static void usage (FILE *, int);
 134 static long get_char (FILE *, file_ptr *, int *, char **);
 135 \f
 136 int main (int, char **);
 137
 138 int
 139 main (int argc, char **argv)
 140 {
 141   int optc;
 142   int exit_status = 0;
 143   bfd_boolean files_given = FALSE;
 144   char *s;
 145   int numeric_opt = 0;
 146
 147 #if defined (HAVE_SETLOCALE)
 148   setlocale (LC_ALL, "");
 149 #endif
 150   bindtextdomain (PACKAGE, LOCALEDIR);
 151   textdomain (PACKAGE);
 152
 153   program_name = argv[0];
 154   xmalloc_set_program_name (program_name);
 155
 156   expandargv (&argc, &argv);
 157
 158   string_min = 4;
 159   print_addresses = FALSE;
 160   print_filenames = FALSE;
 161   datasection_only = TRUE;
 162   target = NULL;
 163   encoding = 's';
 164
 165   while ((optc = getopt_long (argc, argv, "afhHn:ot:e:T:Vv0123456789",
 166                               long_options, (int *) 0)) != EOF)
 167     {
 168       switch (optc)
 169         {
 170         case 'a':
 171           datasection_only = FALSE;
 172           break;
 173
 174         case 'f':
 175           print_filenames = TRUE;
 176           break;
 177
 178         case 'H':
 179         case 'h':
 180           usage (stdout, 0);
 181
 182         case 'n':
 183           string_min = (int) strtoul (optarg, &s, 0);
 184           if (s != NULL && *s != 0)
 185             fatal (_("invalid integer argument %s"), optarg);
 186           break;
 187
 188         case 'o':
 189           print_addresses = TRUE;
 190           address_radix = 8;
 191           break;
 192
 193         case 't':
 194           print_addresses = TRUE;
 195           if (optarg[1] != '\0')
 196             usage (stderr, 1);
 197           switch (optarg[0])
 198             {
 199             case 'o':
 200               address_radix = 8;
 201               break;
 202
 203             case 'd':
 204               address_radix = 10;
 205               break;
 206
 207             case 'x':
 208               address_radix = 16;
 209               break;
 210
 211             default:
 212               usage (stderr, 1);
 213             }
 214           break;
 215
 216         case 'T':
 217           target = optarg;
 218           break;
 219
 220         case 'e':
 221           if (optarg[1] != '\0')
 222             usage (stderr, 1);
 223           encoding = optarg[0];
 224           break;
 225
 226         case 'V':
 227         case 'v':
 228           print_version ("strings");
 229           break;
 230
 231         case '?':
 232           usage (stderr, 1);
 233
 234         default:
 235           numeric_opt = optind;
 236           break;
 237         }
 238     }
 239
 240   if (numeric_opt != 0)
 241     {
 242       string_min = (int) strtoul (argv[numeric_opt - 1] + 1, &s, 0);
 243       if (s != NULL && *s != 0)
 244         fatal (_("invalid integer argument %s"), argv[numeric_opt - 1] + 1);
 245     }
 246   if (string_min < 1)
 247     fatal (_("invalid minimum string length %d"), string_min);
 248
 249   switch (encoding)
 250     {
 251     case 'S':
 252     case 's':
 253       encoding_bytes = 1;
 254       break;
 255     case 'b':
 256     case 'l':
 257       encoding_bytes = 2;
 258       break;
 259     case 'B':
 260     case 'L':
 261       encoding_bytes = 4;
 262       break;
 263     default:
 264       usage (stderr, 1);
 265     }
 266
 267   bfd_init ();
 268   set_default_bfd_target ();
 269
 270   if (optind >= argc)
 271     {
 272       datasection_only = FALSE;
 273       SET_BINARY (fileno (stdin));
 274       print_strings ("{standard input}", stdin, 0, 0, 0, (char *) NULL);
 275       files_given = TRUE;
 276     }
 277   else
 278     {
 279       for (; optind < argc; ++optind)
 280         {
 281           if (strcmp (argv[optind], "-") == 0)
 282             datasection_only = FALSE;
 283           else
 284             {
 285               files_given = TRUE;
 286               exit_status |= strings_file (argv[optind]) == FALSE;
 287             }
 288         }
 289     }
 290
 291   if (!files_given)
 292     usage (stderr, 1);
 293
 294   return (exit_status);
 295 }
 296 \f
 297 /* Scan section SECT of the file ABFD, whose printable name is in
 298    ARG->filename and whose size might be in ARG->filesize.  If it
 299    contains initialized data set `got_a_section' and print the
 300    strings in it.
 301
 302    FIXME: We ought to be able to return error codes/messages for
 303    certain conditions.  */
 304
 305 static void
 306 strings_a_section (bfd *abfd, asection *sect, void *arg)
 307 {
 308   filename_and_size_t * filename_and_sizep;
 309   bfd_size_type *filesizep;
 310   bfd_size_type sectsize;
 311   void *mem;
 312
 313   if ((sect->flags & DATA_FLAGS) != DATA_FLAGS)
 314     return;
 315
 316   sectsize = bfd_get_section_size (sect);
 317
 318   if (sectsize <= 0)
 319     return;
 320
 321   /* Get the size of the file.  This might have been cached for us.  */
 322   filename_and_sizep = (filename_and_size_t *) arg;
 323   filesizep = & filename_and_sizep->filesize;
 324
 325   if (*filesizep == 0)
 326     {
 327       struct stat st;
 328
 329       if (bfd_stat (abfd, &st))
 330         return;
 331
 332       /* Cache the result so that we do not repeatedly stat this file.  */
 333       *filesizep = st.st_size;
 334     }
 335
 336   /* Compare the size of the section against the size of the file.
 337      If the section is bigger then the file must be corrupt and
 338      we should not try dumping it.  */
 339   if (sectsize >= *filesizep)
 340     return;
 341
 342   mem = xmalloc (sectsize);
 343
 344   if (bfd_get_section_contents (abfd, sect, mem, (file_ptr) 0, sectsize))
 345     {
 346       got_a_section = TRUE;
 347
 348       print_strings (filename_and_sizep->filename, NULL, sect->filepos,
 349                      0, sectsize, (char *) mem);
 350     }
 351
 352   free (mem);
 353 }
 354
 355 /* Scan all of the sections in FILE, and print the strings
 356    in the initialized data section(s).
 357
 358    Return TRUE if successful,
 359    FALSE if not (such as if FILE is not an object file).  */
 360
 361 static bfd_boolean
 362 strings_object_file (const char *file)
 363 {
 364   filename_and_size_t filename_and_size;
 365   bfd *abfd;
 366
 367   abfd = bfd_openr (file, target);
 368
 369   if (abfd == NULL)
 370     /* Treat the file as a non-object file.  */
 371     return FALSE;
 372
 373   /* This call is mainly for its side effect of reading in the sections.
 374      We follow the traditional behavior of `strings' in that we don't
 375      complain if we don't recognize a file to be an object file.  */
 376   if (!bfd_check_format (abfd, bfd_object))
 377     {
 378       bfd_close (abfd);
 379       return FALSE;
 380     }
 381
 382   got_a_section = FALSE;
 383   filename_and_size.filename = file;
 384   filename_and_size.filesize = 0;
 385   bfd_map_over_sections (abfd, strings_a_section, & filename_and_size);
 386
 387   if (!bfd_close (abfd))
 388     {
 389       bfd_nonfatal (file);
 390       return FALSE;
 391     }
 392
 393   return got_a_section;
 394 }
 395
 396 /* Print the strings in FILE.  Return TRUE if ok, FALSE if an error occurs.  */
 397
 398 static bfd_boolean
 399 strings_file (char *file)
 400 {
 401   struct stat st;
 402
 403   /* get_file_size does not support non-S_ISREG files.  */
 404
 405   if (stat (file, &st) < 0)
 406     {
 407       if (errno == ENOENT)
 408         non_fatal (_("'%s': No such file"), file);
 409       else
 410         non_fatal (_("Warning: could not locate '%s'.  reason: %s"),
 411                    file, strerror (errno));
 412       return FALSE;
 413     }
 414
 415   /* If we weren't told to scan the whole file,
 416      try to open it as an object file and only look at
 417      initialized data sections.  If that fails, fall back to the
 418      whole file.  */
 419   if (!datasection_only || !strings_object_file (file))
 420     {
 421       FILE *stream;
 422
 423       stream = fopen (file, FOPEN_RB);
 424       if (stream == NULL)
 425         {
 426           fprintf (stderr, "%s: ", program_name);
 427           perror (file);
 428           return FALSE;
 429         }
 430
 431       print_strings (file, stream, (file_ptr) 0, 0, 0, (char *) 0);
 432
 433       if (fclose (stream) == EOF)
 434         {
 435           fprintf (stderr, "%s: ", program_name);
 436           perror (file);
 437           return FALSE;
 438         }
 439     }
 440
 441   return TRUE;
 442 }
 443 \f
 444 /* Read the next character, return EOF if none available.
 445    Assume that STREAM is positioned so that the next byte read
 446    is at address ADDRESS in the file.
 447
 448    If STREAM is NULL, do not read from it.
 449    The caller can supply a buffer of characters
 450    to be processed before the data in STREAM.
 451    MAGIC is the address of the buffer and
 452    MAGICCOUNT is how many characters are in it.  */
 453
 454 static long
 455 get_char (FILE *stream, file_ptr *address, int *magiccount, char **magic)
 456 {
 457   int c, i;
 458   long r = 0;
 459
 460   for (i = 0; i < encoding_bytes; i++)
 461     {
 462       if (*magiccount)
 463         {
 464           (*magiccount)--;
 465           c = *(*magic)++;
 466         }
 467       else
 468         {
 469           if (stream == NULL)
 470             return EOF;
 471
 472           /* Only use getc_unlocked if we found a declaration for it.
 473              Otherwise, libc is not thread safe by default, and we
 474              should not use it.  */
 475
 476 #if defined(HAVE_GETC_UNLOCKED) && HAVE_DECL_GETC_UNLOCKED
 477           c = getc_unlocked (stream);
 478 #else
 479           c = getc (stream);
 480 #endif
 481           if (c == EOF)
 482             return EOF;
 483         }
 484
 485       (*address)++;
 486       r = (r << 8) | (c & 0xff);
 487     }
 488
 489   switch (encoding)
 490     {
 491     default:
 492       break;
 493     case 'l':
 494       r = ((r & 0xff) << 8) | ((r & 0xff00) >> 8);
 495       break;
 496     case 'L':
 497       r = (((r & 0xff) << 24) | ((r & 0xff00) << 8)
 498            | ((r & 0xff0000) >> 8) | ((r & 0xff000000) >> 24));
 499       break;
 500     }
 501
 502   return r;
 503 }
 504 \f
 505 /* Find the strings in file FILENAME, read from STREAM.
 506    Assume that STREAM is positioned so that the next byte read
 507    is at address ADDRESS in the file.
 508    Stop reading at address STOP_POINT in the file, if nonzero.
 509
 510    If STREAM is NULL, do not read from it.
 511    The caller can supply a buffer of characters
 512    to be processed before the data in STREAM.
 513    MAGIC is the address of the buffer and
 514    MAGICCOUNT is how many characters are in it.
 515    Those characters come at address ADDRESS and the data in STREAM follow.  */
 516
 517 static void
 518 print_strings (const char *filename, FILE *stream, file_ptr address,
 519                int stop_point, int magiccount, char *magic)
 520 {
 521   char *buf = (char *) xmalloc (sizeof (char) * (string_min + 1));
 522
 523   while (1)
 524     {
 525       file_ptr start;
 526       int i;
 527       long c;
 528
 529       /* See if the next `string_min' chars are all graphic chars.  */
 530     tryline:
 531       if (stop_point && address >= stop_point)
 532         break;
 533       start = address;
 534       for (i = 0; i < string_min; i++)
 535         {
 536           c = get_char (stream, &address, &magiccount, &magic);
 537           if (c == EOF)
 538             {
 539               free (buf);
 540               return;
 541             }
 542           if (! STRING_ISGRAPHIC (c))
 543             /* Found a non-graphic.  Try again starting with next char.  */
 544             goto tryline;
 545           buf[i] = c;
 546         }
 547
 548       /* We found a run of `string_min' graphic characters.  Print up
 549          to the next non-graphic character.  */
 550
 551       if (print_filenames)
 552         printf ("%s: ", filename);
 553       if (print_addresses)
 554         switch (address_radix)
 555           {
 556           case 8:
 557 #if __STDC_VERSION__ >= 199901L || (defined(__GNUC__) && __GNUC__ >= 2)
 558             if (sizeof (start) > sizeof (long))
 559               {
 560 #ifndef __MSVCRT__
 561                 printf ("%7llo ", (unsigned long long) start);
 562 #else
 563                 printf ("%7I64o ", (unsigned long long) start);
 564 #endif
 565               }
 566             else
 567 #elif !BFD_HOST_64BIT_LONG
 568             if (start != (unsigned long) start)
 569               printf ("++%7lo ", (unsigned long) start);
 570             else
 571 #endif
 572               printf ("%7lo ", (unsigned long) start);
 573             break;
 574
 575           case 10:
 576 #if __STDC_VERSION__ >= 199901L || (defined(__GNUC__) && __GNUC__ >= 2)
 577             if (sizeof (start) > sizeof (long))
 578               {
 579 #ifndef __MSVCRT__
 580                 printf ("%7lld ", (unsigned long long) start);
 581 #else
 582                 printf ("%7I64d ", (unsigned long long) start);
 583 #endif
 584               }
 585             else
 586 #elif !BFD_HOST_64BIT_LONG
 587             if (start != (unsigned long) start)
 588               printf ("++%7ld ", (unsigned long) start);
 589             else
 590 #endif
 591               printf ("%7ld ", (long) start);
 592             break;
 593
 594           case 16:
 595 #if __STDC_VERSION__ >= 199901L || (defined(__GNUC__) && __GNUC__ >= 2)
 596             if (sizeof (start) > sizeof (long))
 597               {
 598 #ifndef __MSVCRT__
 599                 printf ("%7llx ", (unsigned long long) start);
 600 #else
 601                 printf ("%7I64x ", (unsigned long long) start);
 602 #endif
 603               }
 604             else
 605 #elif !BFD_HOST_64BIT_LONG
 606             if (start != (unsigned long) start)
 607               printf ("%lx%8.8lx ", (unsigned long) (start >> 32),
 608                       (unsigned long) (start & 0xffffffff));
 609             else
 610 #endif
 611               printf ("%7lx ", (unsigned long) start);
 612             break;
 613           }
 614
 615       buf[i] = '\0';
 616       fputs (buf, stdout);
 617
 618       while (1)
 619         {
 620           c = get_char (stream, &address, &magiccount, &magic);
 621           if (c == EOF)
 622             break;
 623           if (! STRING_ISGRAPHIC (c))
 624             break;
 625           putchar (c);
 626         }
 627
 628       putchar ('\n');
 629     }
 630   free (buf);
 631 }
 632 \f
 633 static void
 634 usage (FILE *stream, int status)
 635 {
 636   fprintf (stream, _("Usage: %s [option(s)] [file(s)]\n"), program_name);
 637   fprintf (stream, _(" Display printable strings in [file(s)] (stdin by default)\n"));
 638   fprintf (stream, _(" The options are:\n\
 639   -a - --all                Scan the entire file, not just the data section\n\
 640   -f --print-file-name      Print the name of the file before each string\n\
 641   -n --bytes=[number]       Locate & print any NUL-terminated sequence of at\n\
 642   -<number>                   least [number] characters (default 4).\n\
 643   -t --radix={o,d,x}        Print the location of the string in base 8, 10 or 16\n\
 644   -o                        An alias for --radix=o\n\
 645   -T --target=<BFDNAME>     Specify the binary file format\n\
 646   -e --encoding={s,S,b,l,B,L} Select character size and endianness:\n\
 647                             s = 7-bit, S = 8-bit, {b,l} = 16-bit, {B,L} = 32-bit\n\
 648   @<file>                   Read options from <file>\n\
 649   -h --help                 Display this information\n\
 650   -v -V --version           Print the program's version number\n"));
 651   list_supported_targets (program_name, stream);
 652   if (REPORT_BUGS_TO[0] && status == 0)
 653     fprintf (stream, _("Report bugs to %s\n"), REPORT_BUGS_TO);
 654   exit (status);
 655 }