121 lines
3.6 KiB
C++
121 lines
3.6 KiB
C++
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/* Target memory searching
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Copyright (C) 2020-2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "gdbsupport/common-defs.h"
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#include "gdbsupport/search.h"
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#include "gdbsupport/byte-vector.h"
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/* This implements a basic search of memory, reading target memory and
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performing the search here (as opposed to performing the search in on the
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target side with, for example, gdbserver). */
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int
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simple_search_memory
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(gdb::function_view<target_read_memory_ftype> read_memory,
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CORE_ADDR start_addr, ULONGEST search_space_len,
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const gdb_byte *pattern, ULONGEST pattern_len,
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CORE_ADDR *found_addrp)
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{
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const unsigned chunk_size = SEARCH_CHUNK_SIZE;
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/* Buffer to hold memory contents for searching. */
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unsigned search_buf_size;
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search_buf_size = chunk_size + pattern_len - 1;
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/* No point in trying to allocate a buffer larger than the search space. */
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if (search_space_len < search_buf_size)
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search_buf_size = search_space_len;
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gdb::byte_vector search_buf (search_buf_size);
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/* Prime the search buffer. */
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if (!read_memory (start_addr, search_buf.data (), search_buf_size))
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{
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warning (_("Unable to access %s bytes of target "
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"memory at %s, halting search."),
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pulongest (search_buf_size), hex_string (start_addr));
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return -1;
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}
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/* Perform the search.
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The loop is kept simple by allocating [N + pattern-length - 1] bytes.
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When we've scanned N bytes we copy the trailing bytes to the start and
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read in another N bytes. */
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while (search_space_len >= pattern_len)
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{
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gdb_byte *found_ptr;
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unsigned nr_search_bytes
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= std::min (search_space_len, (ULONGEST) search_buf_size);
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found_ptr = (gdb_byte *) memmem (search_buf.data (), nr_search_bytes,
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pattern, pattern_len);
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if (found_ptr != NULL)
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{
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CORE_ADDR found_addr = start_addr + (found_ptr - search_buf.data ());
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*found_addrp = found_addr;
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return 1;
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}
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/* Not found in this chunk, skip to next chunk. */
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/* Don't let search_space_len wrap here, it's unsigned. */
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if (search_space_len >= chunk_size)
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search_space_len -= chunk_size;
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else
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search_space_len = 0;
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if (search_space_len >= pattern_len)
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{
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unsigned keep_len = search_buf_size - chunk_size;
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CORE_ADDR read_addr = start_addr + chunk_size + keep_len;
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int nr_to_read;
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/* Copy the trailing part of the previous iteration to the front
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of the buffer for the next iteration. */
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gdb_assert (keep_len == pattern_len - 1);
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if (keep_len > 0)
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memcpy (&search_buf[0], &search_buf[chunk_size], keep_len);
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nr_to_read = std::min (search_space_len - keep_len,
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(ULONGEST) chunk_size);
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if (!read_memory (read_addr, &search_buf[keep_len], nr_to_read))
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{
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warning (_("Unable to access %s bytes of target "
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"memory at %s, halting search."),
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plongest (nr_to_read),
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hex_string (read_addr));
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return -1;
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}
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start_addr += chunk_size;
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}
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}
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/* Not found. */
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return 0;
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}
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