From 4a72de73660810536e9bb416d41dc8a6128f91da Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Wed, 7 Oct 2020 12:07:55 -0600 Subject: Move simple_search_memory to gdbsupport/search.cc This moves the simple_search_memory function to a new file, gdbsupport/search.cc. The API is slightly changed to make it more general. This generality is useful for wiring it to gdbserver, and also for unit testing. gdb/ChangeLog 2020-10-07 Tom Tromey * target.h (simple_search_memory): Don't declare. * target.c (simple_search_memory): Move to gdbsupport. (default_search_memory): Update. * remote.c (remote_target::search_memory): Update. gdbsupport/ChangeLog 2020-10-07 Tom Tromey * Makefile.in: Rebuild. * Makefile.am (libgdbsupport_a_SOURCES): Add search.cc. * search.h: New file. * search.cc: New file. --- gdbsupport/ChangeLog | 7 +++ gdbsupport/Makefile.am | 1 + gdbsupport/Makefile.in | 4 +- gdbsupport/search.cc | 120 +++++++++++++++++++++++++++++++++++++++++++++++++ gdbsupport/search.h | 42 +++++++++++++++++ 5 files changed, 173 insertions(+), 1 deletion(-) create mode 100644 gdbsupport/search.cc create mode 100644 gdbsupport/search.h (limited to 'gdbsupport') diff --git a/gdbsupport/ChangeLog b/gdbsupport/ChangeLog index 05462e6..adcc53a 100644 --- a/gdbsupport/ChangeLog +++ b/gdbsupport/ChangeLog @@ -1,3 +1,10 @@ +2020-10-07 Tom Tromey + + * Makefile.in: Rebuild. + * Makefile.am (libgdbsupport_a_SOURCES): Add search.cc. + * search.h: New file. + * search.cc: New file. + 2020-10-02 Simon Marchi * event-loop.h (debug_event_loop): New variable declaration. diff --git a/gdbsupport/Makefile.am b/gdbsupport/Makefile.am index 9763c96..9f4ec93 100644 --- a/gdbsupport/Makefile.am +++ b/gdbsupport/Makefile.am @@ -65,6 +65,7 @@ libgdbsupport_a_SOURCES = \ run-time-clock.cc \ safe-strerror.cc \ scoped_mmap.cc \ + search.cc \ signals.cc \ signals-state-save-restore.cc \ tdesc.cc \ diff --git a/gdbsupport/Makefile.in b/gdbsupport/Makefile.in index 0223f6d..044ef15 100644 --- a/gdbsupport/Makefile.in +++ b/gdbsupport/Makefile.in @@ -156,7 +156,7 @@ am_libgdbsupport_a_OBJECTS = agent.$(OBJEXT) btrace-common.$(OBJEXT) \ netstuff.$(OBJEXT) new-op.$(OBJEXT) pathstuff.$(OBJEXT) \ print-utils.$(OBJEXT) ptid.$(OBJEXT) rsp-low.$(OBJEXT) \ run-time-clock.$(OBJEXT) safe-strerror.$(OBJEXT) \ - scoped_mmap.$(OBJEXT) signals.$(OBJEXT) \ + scoped_mmap.$(OBJEXT) search.$(OBJEXT) signals.$(OBJEXT) \ signals-state-save-restore.$(OBJEXT) tdesc.$(OBJEXT) \ thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) $(am__objects_1) libgdbsupport_a_OBJECTS = $(am_libgdbsupport_a_OBJECTS) @@ -388,6 +388,7 @@ libgdbsupport_a_SOURCES = \ run-time-clock.cc \ safe-strerror.cc \ scoped_mmap.cc \ + search.cc \ signals.cc \ signals-state-save-restore.cc \ tdesc.cc \ @@ -492,6 +493,7 @@ distclean-compile: @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/run-time-clock.Po@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/safe-strerror.Po@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/scoped_mmap.Po@am__quote@ +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/search.Po@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/selftest.Po@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/signals-state-save-restore.Po@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/signals.Po@am__quote@ diff --git a/gdbsupport/search.cc b/gdbsupport/search.cc new file mode 100644 index 0000000..f10c570 --- /dev/null +++ b/gdbsupport/search.cc @@ -0,0 +1,120 @@ +/* Target memory searching + + Copyright (C) 2020 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 . */ + +#include "gdbsupport/common-defs.h" + +#include "gdbsupport/search.h" +#include "gdbsupport/byte-vector.h" + +/* This implements a basic search of memory, reading target memory and + performing the search here (as opposed to performing the search in on the + target side with, for example, gdbserver). */ + +int +simple_search_memory + (gdb::function_view read_memory, + CORE_ADDR start_addr, ULONGEST search_space_len, + const gdb_byte *pattern, ULONGEST pattern_len, + CORE_ADDR *found_addrp) +{ + const unsigned chunk_size = SEARCH_CHUNK_SIZE; + /* Buffer to hold memory contents for searching. */ + unsigned search_buf_size; + + search_buf_size = chunk_size + pattern_len - 1; + + /* No point in trying to allocate a buffer larger than the search space. */ + if (search_space_len < search_buf_size) + search_buf_size = search_space_len; + + gdb::byte_vector search_buf (search_buf_size); + + /* Prime the search buffer. */ + + if (!read_memory (start_addr, search_buf.data (), search_buf_size)) + { + warning (_("Unable to access %s bytes of target " + "memory at %s, halting search."), + pulongest (search_buf_size), hex_string (start_addr)); + return -1; + } + + /* Perform the search. + + The loop is kept simple by allocating [N + pattern-length - 1] bytes. + When we've scanned N bytes we copy the trailing bytes to the start and + read in another N bytes. */ + + while (search_space_len >= pattern_len) + { + gdb_byte *found_ptr; + unsigned nr_search_bytes + = std::min (search_space_len, (ULONGEST) search_buf_size); + + found_ptr = (gdb_byte *) memmem (search_buf.data (), nr_search_bytes, + pattern, pattern_len); + + if (found_ptr != NULL) + { + CORE_ADDR found_addr = start_addr + (found_ptr - search_buf.data ()); + + *found_addrp = found_addr; + return 1; + } + + /* Not found in this chunk, skip to next chunk. */ + + /* Don't let search_space_len wrap here, it's unsigned. */ + if (search_space_len >= chunk_size) + search_space_len -= chunk_size; + else + search_space_len = 0; + + if (search_space_len >= pattern_len) + { + unsigned keep_len = search_buf_size - chunk_size; + CORE_ADDR read_addr = start_addr + chunk_size + keep_len; + int nr_to_read; + + /* Copy the trailing part of the previous iteration to the front + of the buffer for the next iteration. */ + gdb_assert (keep_len == pattern_len - 1); + if (keep_len > 0) + memcpy (&search_buf[0], &search_buf[chunk_size], keep_len); + + nr_to_read = std::min (search_space_len - keep_len, + (ULONGEST) chunk_size); + + if (!read_memory (read_addr, &search_buf[keep_len], nr_to_read)) + { + warning (_("Unable to access %s bytes of target " + "memory at %s, halting search."), + plongest (nr_to_read), + hex_string (read_addr)); + return -1; + } + + start_addr += chunk_size; + } + } + + /* Not found. */ + + return 0; +} diff --git a/gdbsupport/search.h b/gdbsupport/search.h new file mode 100644 index 0000000..886d80f --- /dev/null +++ b/gdbsupport/search.h @@ -0,0 +1,42 @@ +/* Copyright (C) 2020 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 . */ + +#ifndef COMMON_SEARCH_H +#define COMMON_SEARCH_H + +#include "gdbsupport/function-view.h" + +/* This is needed by the unit test, so appears here. */ +#define SEARCH_CHUNK_SIZE 16000 + +/* The type of a callback function that can be used to read memory. + Note that target_read_memory is not used here, because gdbserver + wants to be able to examine trace data when searching, and + target_read_memory does not do this. */ + +typedef bool target_read_memory_ftype (CORE_ADDR, gdb_byte *, size_t); + +/* Utility implementation of searching memory. */ +extern int simple_search_memory + (gdb::function_view read_memory, + CORE_ADDR start_addr, + ULONGEST search_space_len, + const gdb_byte *pattern, + ULONGEST pattern_len, + CORE_ADDR *found_addrp); + +#endif /* COMMON_SEARCH_H */ -- cgit v1.1