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/* The find command.
Copyright (C) 2008-2021 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "arch-utils.h"
#include <ctype.h>
#include "gdbcmd.h"
#include "value.h"
#include "target.h"
#include "cli/cli-utils.h"
#include <algorithm>
#include "gdbsupport/byte-vector.h"
/* Copied from bfd_put_bits. */
static void
put_bits (bfd_uint64_t data, gdb::byte_vector &buf, int bits, bfd_boolean big_p)
{
int i;
int bytes;
gdb_assert (bits % 8 == 0);
bytes = bits / 8;
size_t last = buf.size ();
buf.resize (last + bytes);
for (i = 0; i < bytes; i++)
{
int index = big_p ? bytes - i - 1 : i;
buf[last + index] = data & 0xff;
data >>= 8;
}
}
/* Subroutine of find_command to simplify it.
Parse the arguments of the "find" command. */
static gdb::byte_vector
parse_find_args (const char *args, ULONGEST *max_countp,
CORE_ADDR *start_addrp, ULONGEST *search_space_lenp,
bfd_boolean big_p)
{
/* Default to using the specified type. */
char size = '\0';
ULONGEST max_count = ~(ULONGEST) 0;
/* Buffer to hold the search pattern. */
gdb::byte_vector pattern_buf;
CORE_ADDR start_addr;
ULONGEST search_space_len;
const char *s = args;
struct value *v;
if (args == NULL)
error (_("Missing search parameters."));
/* Get search granularity and/or max count if specified.
They may be specified in either order, together or separately. */
while (*s == '/')
{
++s;
while (*s != '\0' && *s != '/' && !isspace (*s))
{
if (isdigit (*s))
{
max_count = atoi (s);
while (isdigit (*s))
++s;
continue;
}
switch (*s)
{
case 'b':
case 'h':
case 'w':
case 'g':
size = *s++;
break;
default:
error (_("Invalid size granularity."));
}
}
s = skip_spaces (s);
}
/* Get the search range. */
v = parse_to_comma_and_eval (&s);
start_addr = value_as_address (v);
if (*s == ',')
++s;
s = skip_spaces (s);
if (*s == '+')
{
LONGEST len;
++s;
v = parse_to_comma_and_eval (&s);
len = value_as_long (v);
if (len == 0)
{
printf_filtered (_("Empty search range.\n"));
return pattern_buf;
}
if (len < 0)
error (_("Invalid length."));
/* Watch for overflows. */
if (len > CORE_ADDR_MAX
|| (start_addr + len - 1) < start_addr)
error (_("Search space too large."));
search_space_len = len;
}
else
{
CORE_ADDR end_addr;
v = parse_to_comma_and_eval (&s);
end_addr = value_as_address (v);
if (start_addr > end_addr)
error (_("Invalid search space, end precedes start."));
search_space_len = end_addr - start_addr + 1;
/* We don't support searching all of memory
(i.e. start=0, end = 0xff..ff).
Bail to avoid overflows later on. */
if (search_space_len == 0)
error (_("Overflow in address range "
"computation, choose smaller range."));
}
if (*s == ',')
++s;
/* Fetch the search string. */
while (*s != '\0')
{
LONGEST x;
struct type *t;
s = skip_spaces (s);
v = parse_to_comma_and_eval (&s);
t = value_type (v);
if (size != '\0')
{
x = value_as_long (v);
switch (size)
{
case 'b':
pattern_buf.push_back (x);
break;
case 'h':
put_bits (x, pattern_buf, 16, big_p);
break;
case 'w':
put_bits (x, pattern_buf, 32, big_p);
break;
case 'g':
put_bits (x, pattern_buf, 64, big_p);
break;
}
}
else
{
const gdb_byte *contents = value_contents (v).data ();
pattern_buf.insert (pattern_buf.end (), contents,
contents + TYPE_LENGTH (t));
}
if (*s == ',')
++s;
s = skip_spaces (s);
}
if (pattern_buf.empty ())
error (_("Missing search pattern."));
if (search_space_len < pattern_buf.size ())
error (_("Search space too small to contain pattern."));
*max_countp = max_count;
*start_addrp = start_addr;
*search_space_lenp = search_space_len;
return pattern_buf;
}
static void
find_command (const char *args, int from_tty)
{
struct gdbarch *gdbarch = get_current_arch ();
bfd_boolean big_p = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG;
/* Command line parameters.
These are initialized to avoid uninitialized warnings from -Wall. */
ULONGEST max_count = 0;
CORE_ADDR start_addr = 0;
ULONGEST search_space_len = 0;
/* End of command line parameters. */
unsigned int found_count;
CORE_ADDR last_found_addr;
gdb::byte_vector pattern_buf = parse_find_args (args, &max_count,
&start_addr,
&search_space_len,
big_p);
/* Perform the search. */
found_count = 0;
last_found_addr = 0;
while (search_space_len >= pattern_buf.size ()
&& found_count < max_count)
{
/* Offset from start of this iteration to the next iteration. */
ULONGEST next_iter_incr;
CORE_ADDR found_addr;
int found = target_search_memory (start_addr, search_space_len,
pattern_buf.data (),
pattern_buf.size (),
&found_addr);
if (found <= 0)
break;
print_address (gdbarch, found_addr, gdb_stdout);
printf_filtered ("\n");
++found_count;
last_found_addr = found_addr;
/* Begin next iteration at one byte past this match. */
next_iter_incr = (found_addr - start_addr) + 1;
/* For robustness, we don't let search_space_len go -ve here. */
if (search_space_len >= next_iter_incr)
search_space_len -= next_iter_incr;
else
search_space_len = 0;
start_addr += next_iter_incr;
}
/* Record and print the results. */
set_internalvar_integer (lookup_internalvar ("numfound"), found_count);
if (found_count > 0)
{
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
set_internalvar (lookup_internalvar ("_"),
value_from_pointer (ptr_type, last_found_addr));
}
if (found_count == 0)
printf_filtered ("Pattern not found.\n");
else
printf_filtered ("%d pattern%s found.\n", found_count,
found_count > 1 ? "s" : "");
}
void _initialize_mem_search ();
void
_initialize_mem_search ()
{
add_cmd ("find", class_vars, find_command, _("\
Search memory for a sequence of bytes.\n\
Usage:\nfind \
[/SIZE-CHAR] [/MAX-COUNT] START-ADDRESS, END-ADDRESS, EXPR1 [, EXPR2 ...]\n\
find [/SIZE-CHAR] [/MAX-COUNT] START-ADDRESS, +LENGTH, EXPR1 [, EXPR2 ...]\n\
SIZE-CHAR is one of b,h,w,g for 8,16,32,64 bit values respectively,\n\
and if not specified the size is taken from the type of the expression\n\
in the current language.\n\
The two-address form specifies an inclusive range.\n\
Note that this means for example that in the case of C-like languages\n\
a search for an untyped 0x42 will search for \"(int) 0x42\"\n\
which is typically four bytes, and a search for a string \"hello\" will\n\
include the trailing '\\0'. The null terminator can be removed from\n\
searching by using casts, e.g.: {char[5]}\"hello\".\n\
\n\
The address of the last match is stored as the value of \"$_\".\n\
Convenience variable \"$numfound\" is set to the number of matches."),
&cmdlist);
}