[PATCH v2 2/6] Move simple_search_memory to gdbsupport/search.cc
Tom Tromey
tromey@adacore.com
Fri Sep 25 19:49:09 GMT 2020
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
2020-09-25 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
2020-09-25 Tom Tromey <tromey@adacore.com>
* Makefile.in: Rebuild.
* Makefile.am (libgdbsupport_a_SOURCES): Add search.cc.
* search.h: New file.
* search.cc: New file.
---
gdb/ChangeLog | 7 +++
gdb/remote.c | 11 +++-
gdb/target.c | 110 +++----------------------------------
gdb/target.h | 8 ---
gdbsupport/ChangeLog | 7 +++
gdbsupport/Makefile.am | 1 +
gdbsupport/Makefile.in | 4 +-
gdbsupport/search.cc | 120 +++++++++++++++++++++++++++++++++++++++++
gdbsupport/search.h | 42 +++++++++++++++
9 files changed, 197 insertions(+), 113 deletions(-)
create mode 100644 gdbsupport/search.cc
create mode 100644 gdbsupport/search.h
diff --git a/gdb/remote.c b/gdb/remote.c
index 5fc80ebc8f7..2c0fa4800f6 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -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"
@@ -11184,6 +11185,12 @@ 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
@@ -11203,7 +11210,7 @@ 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);
}
@@ -11235,7 +11242,7 @@ 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;
diff --git a/gdb/target.c b/gdb/target.c
index 9fd6b4ba9e1..4a9f1fcd836 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -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"
@@ -2160,106 +2161,6 @@ 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. */
@@ -2269,9 +2170,14 @@ 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);
}
diff --git a/gdb/target.h b/gdb/target.h
index 0cb92fa8ea8..17e1e890ef5 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -2135,14 +2135,6 @@ 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,
diff --git a/gdbsupport/Makefile.am b/gdbsupport/Makefile.am
index 9763c96cd3d..9f4ec938b98 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 0223f6d6b35..044ef1555c2 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 00000000000..f10c57046cc
--- /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 <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;
+}
diff --git a/gdbsupport/search.h b/gdbsupport/search.h
new file mode 100644
index 00000000000..886d80feaeb
--- /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 <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 */
--
2.26.2
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