gdb/findcmd.c

   1 /* The find command.
   2
   3    Copyright (C) 2008-2024 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 "arch-utils.h"
  21 #include <ctype.h>
  22 #include "cli/cli-cmds.h"
  23 #include "value.h"
  24 #include "target.h"
  25 #include "cli/cli-utils.h"
  26 #include <algorithm>
  27 #include "gdbsupport/byte-vector.h"
  28
  29 /* Copied from bfd_put_bits.  */
  30
  31 static void
  32 put_bits (uint64_t data, gdb::byte_vector &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   size_t last = buf.size ();
  41   buf.resize (last + bytes);
  42   for (i = 0; i < bytes; i++)
  43     {
  44       int index = big_p ? bytes - i - 1 : i;
  45
  46       buf[last + index] = data & 0xff;
  47       data >>= 8;
  48     }
  49 }
  50
  51 /* Subroutine of find_command to simplify it.
  52    Parse the arguments of the "find" command.  */
  53
  54 static gdb::byte_vector
  55 parse_find_args (const char *args, ULONGEST *max_countp,
  56                  CORE_ADDR *start_addrp, ULONGEST *search_space_lenp,
  57                  bfd_boolean big_p)
  58 {
  59   /* Default to using the specified type.  */
  60   char size = '\0';
  61   ULONGEST max_count = ~(ULONGEST) 0;
  62   /* Buffer to hold the search pattern.  */
  63   gdb::byte_vector pattern_buf;
  64   CORE_ADDR start_addr;
  65   ULONGEST search_space_len;
  66   const char *s = args;
  67   struct value *v;
  68
  69   if (args == NULL)
  70     error (_("Missing search parameters."));
  71
  72   /* Get search granularity and/or max count if specified.
  73      They may be specified in either order, together or separately.  */
  74
  75   while (*s == '/')
  76     {
  77       ++s;
  78
  79       while (*s != '\0' && *s != '/' && !isspace (*s))
  80         {
  81           if (isdigit (*s))
  82             {
  83               max_count = atoi (s);
  84               while (isdigit (*s))
  85                 ++s;
  86               continue;
  87             }
  88
  89           switch (*s)
  90             {
  91             case 'b':
  92             case 'h':
  93             case 'w':
  94             case 'g':
  95               size = *s++;
  96               break;
  97             default:
  98               error (_("Invalid size granularity."));
  99             }
 100         }
 101
 102       s = skip_spaces (s);
 103     }
 104
 105   /* Get the search range.  */
 106
 107   v = parse_to_comma_and_eval (&s);
 108   start_addr = value_as_address (v);
 109
 110   if (*s == ',')
 111     ++s;
 112   s = skip_spaces (s);
 113
 114   if (*s == '+')
 115     {
 116       LONGEST len;
 117
 118       ++s;
 119       v = parse_to_comma_and_eval (&s);
 120       len = value_as_long (v);
 121       if (len == 0)
 122         {
 123           gdb_printf (_("Empty search range.\n"));
 124           return pattern_buf;
 125         }
 126       if (len < 0)
 127         error (_("Invalid length."));
 128       /* Watch for overflows.  */
 129       if (len > CORE_ADDR_MAX
 130           || (start_addr + len - 1) < start_addr)
 131         error (_("Search space too large."));
 132       search_space_len = len;
 133     }
 134   else
 135     {
 136       CORE_ADDR end_addr;
 137
 138       v = parse_to_comma_and_eval (&s);
 139       end_addr = value_as_address (v);
 140       if (start_addr > end_addr)
 141         error (_("Invalid search space, end precedes start."));
 142       search_space_len = end_addr - start_addr + 1;
 143       /* We don't support searching all of memory
 144          (i.e. start=0, end = 0xff..ff).
 145          Bail to avoid overflows later on.  */
 146       if (search_space_len == 0)
 147         error (_("Overflow in address range "
 148                  "computation, choose smaller range."));
 149     }
 150
 151   if (*s == ',')
 152     ++s;
 153
 154   /* Fetch the search string.  */
 155
 156   while (*s != '\0')
 157     {
 158       LONGEST x;
 159       struct type *t;
 160
 161       s = skip_spaces (s);
 162
 163       v = parse_to_comma_and_eval (&s);
 164       t = v->type ();
 165
 166       if (size != '\0')
 167         {
 168           x = value_as_long (v);
 169           switch (size)
 170             {
 171             case 'b':
 172               pattern_buf.push_back (x);
 173               break;
 174             case 'h':
 175               put_bits (x, pattern_buf, 16, big_p);
 176               break;
 177             case 'w':
 178               put_bits (x, pattern_buf, 32, big_p);
 179               break;
 180             case 'g':
 181               put_bits (x, pattern_buf, 64, big_p);
 182               break;
 183             }
 184         }
 185       else
 186         {
 187           const gdb_byte *contents = v->contents ().data ();
 188           pattern_buf.insert (pattern_buf.end (), contents,
 189                               contents + t->length ());
 190         }
 191
 192       if (*s == ',')
 193         ++s;
 194       s = skip_spaces (s);
 195     }
 196
 197   if (pattern_buf.empty ())
 198     error (_("Missing search pattern."));
 199
 200   if (search_space_len < pattern_buf.size ())
 201     error (_("Search space too small to contain pattern."));
 202
 203   *max_countp = max_count;
 204   *start_addrp = start_addr;
 205   *search_space_lenp = search_space_len;
 206
 207   return pattern_buf;
 208 }
 209
 210 static void
 211 find_command (const char *args, int from_tty)
 212 {
 213   struct gdbarch *gdbarch = get_current_arch ();
 214   bfd_boolean big_p = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG;
 215   /* Command line parameters.
 216      These are initialized to avoid uninitialized warnings from -Wall.  */
 217   ULONGEST max_count = 0;
 218   CORE_ADDR start_addr = 0;
 219   ULONGEST search_space_len = 0;
 220   /* End of command line parameters.  */
 221   unsigned int found_count;
 222   CORE_ADDR last_found_addr;
 223
 224   gdb::byte_vector pattern_buf = parse_find_args (args, &max_count,
 225                                                   &start_addr,
 226                                                   &search_space_len,
 227                                                   big_p);
 228
 229   /* Perform the search.  */
 230
 231   found_count = 0;
 232   last_found_addr = 0;
 233
 234   while (search_space_len >= pattern_buf.size ()
 235          && found_count < max_count)
 236     {
 237       /* Offset from start of this iteration to the next iteration.  */
 238       ULONGEST next_iter_incr;
 239       CORE_ADDR found_addr;
 240       int found = target_search_memory (start_addr, search_space_len,
 241                                         pattern_buf.data (),
 242                                         pattern_buf.size (),
 243                                         &found_addr);
 244
 245       if (found <= 0)
 246         break;
 247
 248       print_address (gdbarch, found_addr, gdb_stdout);
 249       gdb_printf ("\n");
 250       ++found_count;
 251       last_found_addr = found_addr;
 252
 253       /* Begin next iteration at one byte past this match.  */
 254       next_iter_incr = (found_addr - start_addr) + 1;
 255
 256       /* For robustness, we don't let search_space_len go -ve here.  */
 257       if (search_space_len >= next_iter_incr)
 258         search_space_len -= next_iter_incr;
 259       else
 260         search_space_len = 0;
 261       start_addr += next_iter_incr;
 262     }
 263
 264   /* Record and print the results.  */
 265
 266   set_internalvar_integer (lookup_internalvar ("numfound"), found_count);
 267   if (found_count > 0)
 268     {
 269       struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
 270
 271       set_internalvar (lookup_internalvar ("_"),
 272                        value_from_pointer (ptr_type, last_found_addr));
 273     }
 274
 275   if (found_count == 0)
 276     gdb_printf ("Pattern not found.\n");
 277   else
 278     gdb_printf ("%d pattern%s found.\n", found_count,
 279                 found_count > 1 ? "s" : "");
 280 }
 281
 282 void _initialize_mem_search ();
 283 void
 284 _initialize_mem_search ()
 285 {
 286   add_cmd ("find", class_vars, find_command, _("\
 287 Search memory for a sequence of bytes.\n\
 288 Usage:\nfind \
 289 [/SIZE-CHAR] [/MAX-COUNT] START-ADDRESS, END-ADDRESS, EXPR1 [, EXPR2 ...]\n\
 290 find [/SIZE-CHAR] [/MAX-COUNT] START-ADDRESS, +LENGTH, EXPR1 [, EXPR2 ...]\n\
 291 SIZE-CHAR is one of b,h,w,g for 8,16,32,64 bit values respectively,\n\
 292 and if not specified the size is taken from the type of the expression\n\
 293 in the current language.\n\
 294 The two-address form specifies an inclusive range.\n\
 295 Note that this means for example that in the case of C-like languages\n\
 296 a search for an untyped 0x42 will search for \"(int) 0x42\"\n\
 297 which is typically four bytes, and a search for a string \"hello\" will\n\
 298 include the trailing '\\0'.  The null terminator can be removed from\n\
 299 searching by using casts, e.g.: {char[5]}\"hello\".\n\
 300 \n\
 301 The address of the last match is stored as the value of \"$_\".\n\
 302 Convenience variable \"$numfound\" is set to the number of matches."),
 303            &cmdlist);
 304 }