gdb/findcmd.c

   1 /* The find command.
   2
   3    Copyright (C) 2008-2013 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "arch-utils.h"
  22 #include <ctype.h>
  23 #include "gdb_string.h"
  24 #include "gdbcmd.h"
  25 #include "value.h"
  26 #include "target.h"
  27 #include "cli/cli-utils.h"
  28
  29 /* Copied from bfd_put_bits.  */
  30
  31 static void
  32 put_bits (bfd_uint64_t data, gdb_byte *buf, int bits, bfd_boolean big_p)
  33 {
  34   int i;
  35   int bytes;
  36
  37   gdb_assert (bits % 8 == 0);
  38
  39   bytes = bits / 8;
  40   for (i = 0; i < bytes; i++)
  41     {
  42       int index = big_p ? bytes - i - 1 : i;
  43
  44       buf[index] = data & 0xff;
  45       data >>= 8;
  46     }
  47 }
  48
  49 /* Subroutine of find_command to simplify it.
  50    Parse the arguments of the "find" command.  */
  51
  52 static void
  53 parse_find_args (char *args, ULONGEST *max_countp,
  54                  gdb_byte **pattern_bufp, ULONGEST *pattern_lenp,
  55                  CORE_ADDR *start_addrp, ULONGEST *search_space_lenp,
  56                  bfd_boolean big_p)
  57 {
  58   /* Default to using the specified type.  */
  59   char size = '\0';
  60   ULONGEST max_count = ~(ULONGEST) 0;
  61   /* Buffer to hold the search pattern.  */
  62   gdb_byte *pattern_buf;
  63   /* Current size of search pattern buffer.
  64      We realloc space as needed.  */
  65 #define INITIAL_PATTERN_BUF_SIZE 100
  66   ULONGEST pattern_buf_size = INITIAL_PATTERN_BUF_SIZE;
  67   /* Pointer to one past the last in-use part of pattern_buf.  */
  68   gdb_byte *pattern_buf_end;
  69   ULONGEST pattern_len;
  70   CORE_ADDR start_addr;
  71   ULONGEST search_space_len;
  72   const char *s = args;
  73   struct cleanup *old_cleanups;
  74   struct value *v;
  75
  76   if (args == NULL)
  77     error (_("Missing search parameters."));
  78
  79   pattern_buf = xmalloc (pattern_buf_size);
  80   pattern_buf_end = pattern_buf;
  81   old_cleanups = make_cleanup (free_current_contents, &pattern_buf);
  82
  83   /* Get search granularity and/or max count if specified.
  84      They may be specified in either order, together or separately.  */
  85
  86   while (*s == '/')
  87     {
  88       ++s;
  89
  90       while (*s != '\0' && *s != '/' && !isspace (*s))
  91         {
  92           if (isdigit (*s))
  93             {
  94               max_count = atoi (s);
  95               while (isdigit (*s))
  96                 ++s;
  97               continue;
  98             }
  99
 100           switch (*s)
 101             {
 102             case 'b':
 103             case 'h':
 104             case 'w':
 105             case 'g':
 106               size = *s++;
 107               break;
 108             default:
 109               error (_("Invalid size granularity."));
 110             }
 111         }
 112
 113       s = skip_spaces_const (s);
 114     }
 115
 116   /* Get the search range.  */
 117
 118   v = parse_to_comma_and_eval (&s);
 119   start_addr = value_as_address (v);
 120
 121   if (*s == ',')
 122     ++s;
 123   s = skip_spaces_const (s);
 124
 125   if (*s == '+')
 126     {
 127       LONGEST len;
 128
 129       ++s;
 130       v = parse_to_comma_and_eval (&s);
 131       len = value_as_long (v);
 132       if (len == 0)
 133         {
 134           do_cleanups (old_cleanups);
 135           printf_filtered (_("Empty search range.\n"));
 136           return;
 137         }
 138       if (len < 0)
 139         error (_("Invalid length."));
 140       /* Watch for overflows.  */
 141       if (len > CORE_ADDR_MAX
 142           || (start_addr + len - 1) < start_addr)
 143         error (_("Search space too large."));
 144       search_space_len = len;
 145     }
 146   else
 147     {
 148       CORE_ADDR end_addr;
 149
 150       v = parse_to_comma_and_eval (&s);
 151       end_addr = value_as_address (v);
 152       if (start_addr > end_addr)
 153         error (_("Invalid search space, end precedes start."));
 154       search_space_len = end_addr - start_addr + 1;
 155       /* We don't support searching all of memory
 156          (i.e. start=0, end = 0xff..ff).
 157          Bail to avoid overflows later on.  */
 158       if (search_space_len == 0)
 159         error (_("Overflow in address range "
 160                  "computation, choose smaller range."));
 161     }
 162
 163   if (*s == ',')
 164     ++s;
 165
 166   /* Fetch the search string.  */
 167
 168   while (*s != '\0')
 169     {
 170       LONGEST x;
 171       struct type *t;
 172       ULONGEST pattern_buf_size_need;
 173
 174       s = skip_spaces_const (s);
 175
 176       v = parse_to_comma_and_eval (&s);
 177       t = value_type (v);
 178
 179       /* Keep it simple and assume size == 'g' when watching for when we
 180          need to grow the pattern buf.  */
 181       pattern_buf_size_need = (pattern_buf_end - pattern_buf
 182                                + max (TYPE_LENGTH (t), sizeof (int64_t)));
 183       if (pattern_buf_size_need > pattern_buf_size)
 184         {
 185           size_t current_offset = pattern_buf_end - pattern_buf;
 186
 187           pattern_buf_size = pattern_buf_size_need * 2;
 188           pattern_buf = xrealloc (pattern_buf, pattern_buf_size);
 189           pattern_buf_end = pattern_buf + current_offset;
 190         }
 191
 192       if (size != '\0')
 193         {
 194           x = value_as_long (v);
 195           switch (size)
 196             {
 197             case 'b':
 198               *pattern_buf_end++ = x;
 199               break;
 200             case 'h':
 201               put_bits (x, pattern_buf_end, 16, big_p);
 202               pattern_buf_end += sizeof (int16_t);
 203               break;
 204             case 'w':
 205               put_bits (x, pattern_buf_end, 32, big_p);
 206               pattern_buf_end += sizeof (int32_t);
 207               break;
 208             case 'g':
 209               put_bits (x, pattern_buf_end, 64, big_p);
 210               pattern_buf_end += sizeof (int64_t);
 211               break;
 212             }
 213         }
 214       else
 215         {
 216           memcpy (pattern_buf_end, value_contents (v), TYPE_LENGTH (t));
 217           pattern_buf_end += TYPE_LENGTH (t);
 218         }
 219
 220       if (*s == ',')
 221         ++s;
 222       s = skip_spaces_const (s);
 223     }
 224
 225   if (pattern_buf_end == pattern_buf)
 226     error (_("Missing search pattern."));
 227
 228   pattern_len = pattern_buf_end - pattern_buf;
 229
 230   if (search_space_len < pattern_len)
 231     error (_("Search space too small to contain pattern."));
 232
 233   *max_countp = max_count;
 234   *pattern_bufp = pattern_buf;
 235   *pattern_lenp = pattern_len;
 236   *start_addrp = start_addr;
 237   *search_space_lenp = search_space_len;
 238
 239   /* We successfully parsed the arguments, leave the freeing of PATTERN_BUF
 240      to the caller now.  */
 241   discard_cleanups (old_cleanups);
 242 }
 243
 244 static void
 245 find_command (char *args, int from_tty)
 246 {
 247   struct gdbarch *gdbarch = get_current_arch ();
 248   bfd_boolean big_p = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG;
 249   /* Command line parameters.
 250      These are initialized to avoid uninitialized warnings from -Wall.  */
 251   ULONGEST max_count = 0;
 252   gdb_byte *pattern_buf = 0;
 253   ULONGEST pattern_len = 0;
 254   CORE_ADDR start_addr = 0;
 255   ULONGEST search_space_len = 0;
 256   /* End of command line parameters.  */
 257   unsigned int found_count;
 258   CORE_ADDR last_found_addr;
 259   struct cleanup *old_cleanups;
 260
 261   parse_find_args (args, &max_count, &pattern_buf, &pattern_len,
 262                    &start_addr, &search_space_len, big_p);
 263
 264   old_cleanups = make_cleanup (free_current_contents, &pattern_buf);
 265
 266   /* Perform the search.  */
 267
 268   found_count = 0;
 269   last_found_addr = 0;
 270
 271   while (search_space_len >= pattern_len
 272          && found_count < max_count)
 273     {
 274       /* Offset from start of this iteration to the next iteration.  */
 275       ULONGEST next_iter_incr;
 276       CORE_ADDR found_addr;
 277       int found = target_search_memory (start_addr, search_space_len,
 278                                         pattern_buf, pattern_len, &found_addr);
 279
 280       if (found <= 0)
 281         break;
 282
 283       print_address (gdbarch, found_addr, gdb_stdout);
 284       printf_filtered ("\n");
 285       ++found_count;
 286       last_found_addr = found_addr;
 287
 288       /* Begin next iteration at one byte past this match.  */
 289       next_iter_incr = (found_addr - start_addr) + 1;
 290
 291       /* For robustness, we don't let search_space_len go -ve here.  */
 292       if (search_space_len >= next_iter_incr)
 293         search_space_len -= next_iter_incr;
 294       else
 295         search_space_len = 0;
 296       start_addr += next_iter_incr;
 297     }
 298
 299   /* Record and print the results.  */
 300
 301   set_internalvar_integer (lookup_internalvar ("numfound"), found_count);
 302   if (found_count > 0)
 303     {
 304       struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
 305
 306       set_internalvar (lookup_internalvar ("_"),
 307                        value_from_pointer (ptr_type, last_found_addr));
 308     }
 309
 310   if (found_count == 0)
 311     printf_filtered ("Pattern not found.\n");
 312   else
 313     printf_filtered ("%d pattern%s found.\n", found_count,
 314                      found_count > 1 ? "s" : "");
 315
 316   do_cleanups (old_cleanups);
 317 }
 318
 319 /* Provide a prototype to silence -Wmissing-prototypes.  */
 320 extern initialize_file_ftype _initialize_mem_search;
 321
 322 void
 323 _initialize_mem_search (void)
 324 {
 325   add_cmd ("find", class_vars, find_command, _("\
 326 Search memory for a sequence of bytes.\n\
 327 Usage:\nfind \
 328 [/size-char] [/max-count] start-address, end-address, expr1 [, expr2 ...]\n\
 329 find [/size-char] [/max-count] start-address, +length, expr1 [, expr2 ...]\n\
 330 size-char is one of b,h,w,g for 8,16,32,64 bit values respectively,\n\
 331 and if not specified the size is taken from the type of the expression\n\
 332 in the current language.\n\
 333 Note that this means for example that in the case of C-like languages\n\
 334 a search for an untyped 0x42 will search for \"(int) 0x42\"\n\
 335 which is typically four bytes.\n\
 336 \n\
 337 The address of the last match is stored as the value of \"$_\".\n\
 338 Convenience variable \"$numfound\" is set to the number of matches."),
 339            &cmdlist);
 340 }