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Move simple_search_memory to gdbsupport/search.cc

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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  <tromey@adacore.com>

	* 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  <tromey@adacore.com>

	* Makefile.in: Rebuild.
	* Makefile.am (libgdbsupport_a_SOURCES): Add search.cc.
	* search.h: New file.
	* search.cc: New file.
This commit is contained in:
Tom Tromey
2020-10-07 12:07:55 -06:00
parent e86efb3310
commit 4a72de7366
9 changed files with 197 additions and 113 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
gdb/ChangeLog
View File

@@ -1,3 +1,10 @@
2020-10-07 Tom Tromey <tromey@adacore.com>
* 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.
2020-10-07 Simon Marchi <simon.marchi@efficios.com>
* Makefile.in (COMPILE): Add CXXFLAGS.

11
gdb/remote.c
View File

@@ -75,6 +75,7 @@
#include "gdbsupport/scoped_restore.h"
#include "gdbsupport/environ.h"
#include "gdbsupport/byte-vector.h"
#include "gdbsupport/search.h"
#include <algorithm>
#include <unordered_map>
#include "async-event.h"
@@ -11186,6 +11187,12 @@ remote_target::search_memory (CORE_ADDR start_addr, ULONGEST search_space_len,
int found;
ULONGEST found_addr;
auto read_memory = [=] (CORE_ADDR addr, gdb_byte *result, size_t len)
{
return (target_read (this, TARGET_OBJECT_MEMORY, NULL, result, addr, len)
== len);
};
/* Don't go to the target if we don't have to. This is done before
checking packet_config_support to avoid the possibility that a
success for this edge case means the facility works in
@@ -11205,7 +11212,7 @@ remote_target::search_memory (CORE_ADDR start_addr, ULONGEST search_space_len,
{
/* Target doesn't provided special support, fall back and use the
standard support (copy memory and do the search here). */
return simple_search_memory (this, start_addr, search_space_len,
return simple_search_memory (read_memory, start_addr, search_space_len,
pattern, pattern_len, found_addrp);
}
@@ -11237,7 +11244,7 @@ remote_target::search_memory (CORE_ADDR start_addr, ULONGEST search_space_len,
supported. If so, fall back to the simple way. */
if (packet_config_support (packet) == PACKET_DISABLE)
{
return simple_search_memory (this, start_addr, search_space_len,
return simple_search_memory (read_memory, start_addr, search_space_len,
pattern, pattern_len, found_addrp);
}
return -1;

110
gdb/target.c
View File

@@ -47,6 +47,7 @@
#include "event-top.h"
#include <algorithm>
#include "gdbsupport/byte-vector.h"
#include "gdbsupport/search.h"
#include "terminal.h"
#include <unordered_map>
#include "target-connection.h"
@@ -2147,106 +2148,6 @@ target_read_description (struct target_ops *target)
return target->read_description ();
}
/* 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 (struct target_ops *ops,
CORE_ADDR start_addr, ULONGEST search_space_len,
const gdb_byte *pattern, ULONGEST pattern_len,
CORE_ADDR *found_addrp)
{
/* NOTE: also defined in find.c testcase. */
#define SEARCH_CHUNK_SIZE 16000
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 (target_read (ops, TARGET_OBJECT_MEMORY, NULL,
search_buf.data (), start_addr, search_buf_size)
!= 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);
memcpy (&search_buf[0], &search_buf[chunk_size], keep_len);
nr_to_read = std::min (search_space_len - keep_len,
(ULONGEST) chunk_size);
if (target_read (ops, TARGET_OBJECT_MEMORY, NULL,
&search_buf[keep_len], read_addr,
nr_to_read) != 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;
}
/* Default implementation of memory-searching. */
@@ -2256,9 +2157,14 @@ default_search_memory (struct target_ops *self,
const gdb_byte *pattern, ULONGEST pattern_len,
CORE_ADDR *found_addrp)
{
auto read_memory = [=] (CORE_ADDR addr, gdb_byte *result, size_t len)
{
return target_read (current_top_target (), TARGET_OBJECT_MEMORY, NULL,
result, addr, len) == len;
};
/* Start over from the top of the target stack. */
return simple_search_memory (current_top_target (),
start_addr, search_space_len,
return simple_search_memory (read_memory, start_addr, search_space_len,
pattern, pattern_len, found_addrp);
}

8
gdb/target.h
View File

@@ -2129,14 +2129,6 @@ extern const struct target_desc *target_read_description (struct target_ops *);
#define target_get_ada_task_ptid(lwp, tid) \
(current_top_target ()->get_ada_task_ptid) (lwp,tid)
/* Utility implementation of searching memory. */
extern int simple_search_memory (struct target_ops* ops,
CORE_ADDR start_addr,
ULONGEST search_space_len,
const gdb_byte *pattern,
ULONGEST pattern_len,
CORE_ADDR *found_addrp);
/* Main entry point for searching memory. */
extern int target_search_memory (CORE_ADDR start_addr,
ULONGEST search_space_len,

7
gdbsupport/ChangeLog
View File

@@ -1,3 +1,10 @@
2020-10-07 Tom Tromey <tromey@adacore.com>
* Makefile.in: Rebuild.
* Makefile.am (libgdbsupport_a_SOURCES): Add search.cc.
* search.h: New file.
* search.cc: New file.
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* event-loop.h (debug_event_loop): New variable declaration.

1
gdbsupport/Makefile.am
View File

@@ -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 \

4
gdbsupport/Makefile.in
View File

@@ -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@

120
gdbsupport/search.cc Normal file
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@@ -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 <http://www.gnu.org/licenses/>. */
#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<target_read_memory_ftype> 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;
}

42
gdbsupport/search.h Normal file
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@@ -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 <http://www.gnu.org/licenses/>. */
#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<target_read_memory_ftype> 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 */