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Easier and more stubborn MI memory read commands.

Browse Source 
* mi/mi-cmds.c (mi_cmds): Register data-read-memory-bytes
	and data-write-memory-bytes.
	* mi/mi-cmds.h (mi_cmd_data_read_memory_bytes)
	(mi_cmd_data_write_memory_bytes): New.
	* mi/mi-main.c (mi_cmd_data_read_memory): Use regular target_read.
	(mi_cmd_data_read_memory_bytes, mi_cmd_data_write_memory_bytes):
	New.
	(mi_cmd_list_features): Add "data-read-memory-bytes" feature.
	* target.c (target_read_until_error): Remove.
	(read_whatever_is_readable, free_memory_read_result_vector)
	(read_memory_robust): New.
	* target.h (target_read_until_error): Remove.
	(struct memory_read_result, free_memory_read_result_vector)
	(read_memory_robust): New.
This commit is contained in:
Vladimir Prus 2010-08-13 13:22:44 +00:00
parent f608cd77e7
commit 8dedea0203
8 changed files with 485 additions and 65 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
gdb/ChangeLog
View File

@ -1,3 +1,22 @@
2010-08-13 Vladimir Prus <vladimir@codesourcery.com>
Easier and more stubborn MI memory read commands.
* mi/mi-cmds.c (mi_cmds): Register data-read-memory-bytes
and data-write-memory-bytes.
* mi/mi-cmds.h (mi_cmd_data_read_memory_bytes)
(mi_cmd_data_write_memory_bytes): New.
* mi/mi-main.c (mi_cmd_data_read_memory): Use regular target_read.
(mi_cmd_data_read_memory_bytes, mi_cmd_data_write_memory_bytes):
New.
(mi_cmd_list_features): Add "data-read-memory-bytes" feature.
* target.c (target_read_until_error): Remove.
(read_whatever_is_readable, free_memory_read_result_vector)
(read_memory_robust): New.
* target.h (target_read_until_error): Remove.
(struct memory_read_result, free_memory_read_result_vector)
(read_memory_robust): New.
2010-08-13 Hui Zhu <teawater@gmail.com>
* dwarf2read.c (load_partial_comp_unit): Initialize free_cu_cleanup.

5
gdb/doc/ChangeLog
View File

@ -1,3 +1,8 @@
2010-08-13 Vladimir Prus <vladimir@codesourcery.com>
* gdb.texinfo (GDB/MI Data Manipulation): Document
-data-read-memory-raw and -data-write-memory-raw.
2010-08-11 Tom Tromey <tromey@redhat.com>
Phil Muldoon <pmuldoon@redhat.com>

127
gdb/doc/gdb.texinfo
View File

@ -27375,6 +27375,8 @@ don't appear in the actual output):
@subheading The @code{-data-read-memory} Command
@findex -data-read-memory
This command is deprecated, use @code{-data-read-memory-bytes} instead.
@subsubheading Synopsis
@smallexample
@ -27486,6 +27488,128 @@ next-page="0x000013c0",prev-page="0x00001380",memory=[
(gdb)
@end smallexample
@subheading The @code{-data-read-memory-bytes} Command
@findex -data-read-memory-bytes
@subsubheading Synopsis
@smallexample
-data-read-memory-bytes [ -o @var{byte-offset} ]
@var{address} @var{count}
@end smallexample
@noindent
where:
@table @samp
@item @var{address}
An expression specifying the address of the first memory word to be
read. Complex expressions containing embedded white space should be
quoted using the C convention.
@item @var{count}
The number of bytes to read. This should be an integer literal.
@item @var{byte-offset}
The offsets in bytes relative to @var{address} at which to start
reading. This should be an integer literal. This option is provided
so that a frontend is not required to first evaluate address and then
perform address arithmetics itself.
@end table
This command attempts to read all accessible memory regions in the
specified range. First, all regions marked as unreadable in the memory
map (if one is defined) will be skipped. @xref{Memory Region
Attributes}. Second, @value{GDBN} will attempt to read the remaining
regions. For each one, if reading full region results in an errors,
@value{GDBN} will try to read a subset of the region.
In general, every single byte in the region may be readable or not,
and the only way to read every readable byte is to try a read at
every address, which is not practical. Therefore, @value{GDBN} will
attempt to read all accessible bytes at either beginning or the end
of the region, using a binary division scheme. This heuristic works
well for reading accross a memory map boundary. Note that if a region
has a readable range that is neither at the beginning or the end,
@value{GDBN} will not read it.
The result record (@pxref{GDB/MI Result Records}) that is output of
the command includes a field named @samp{memory} whose content is a
list of tuples. Each tuple represent a successfully read memory block
and has the following fields:
@table @code
@item begin
The start address of the memory block, as hexadecimal literal.
@item end
The end address of the memory block, as hexadecimal literal.
@item offset
The offset of the memory block, as hexadecimal literal, relative to
the start address passed to @code{-data-read-memory-bytes}.
@item contents
The contents of the memory block, in hex.
@end table
@subsubheading @value{GDBN} Command
The corresponding @value{GDBN} command is @samp{x}.
@subsubheading Example
@smallexample
(gdb)
-data-read-memory-bytes &a 10
^done,memory=[@{begin="0xbffff154",offset="0x00000000",
end="0xbffff15e",
contents="01000000020000000300"@}]
(gdb)
@end smallexample
@subheading The @code{-data-write-memory-bytes} Command
@findex -data-write-memory-bytes
@subsubheading Synopsis
@smallexample
-data-write-memory-bytes @var{address} @var{contents}
@end smallexample
@noindent
where:
@table @samp
@item @var{address}
An expression specifying the address of the first memory word to be
read. Complex expressions containing embedded white space should be
quoted using the C convention.
@item @var{contents}
The hex-encoded bytes to write.
@end table
@subsubheading @value{GDBN} Command
There's no corresponding @value{GDBN} command.
@subsubheading Example
@smallexample
(gdb)
-data-write-memory-bytes &a "aabbccdd"
^done
(gdb)
@end smallexample
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node GDB/MI Tracepoint Commands
@section @sc{gdb/mi} Tracepoint Commands
@ -28824,6 +28948,9 @@ pretty-printing commands, and possible presence of the
@samp{display_hint} field in the output of @code{-var-list-children}
@item thread-info
Indicates presence of the @code{-thread-info} command.
@item data-read-memory-bytes
Indicates presense of the @code{-data-read-memory-bytes} and the
@code{-data-write-memory-bytes} commands.
@end table

2
gdb/mi/mi-cmds.c
View File

@ -51,7 +51,9 @@ struct mi_cmd mi_cmds[] =
{ "data-list-register-names", { NULL, 0 }, mi_cmd_data_list_register_names},
{ "data-list-register-values", { NULL, 0 }, mi_cmd_data_list_register_values},
{ "data-read-memory", { NULL, 0 }, mi_cmd_data_read_memory},
{ "data-read-memory-bytes", { NULL, 0 }, mi_cmd_data_read_memory_bytes},
{ "data-write-memory", { NULL, 0 }, mi_cmd_data_write_memory},
{ "data-write-memory-bytes", {NULL, 0}, mi_cmd_data_write_memory_bytes},
{ "data-write-register-values", { NULL, 0 }, mi_cmd_data_write_register_values},
{ "enable-timings", { NULL, 0 }, mi_cmd_enable_timings},
{ "enable-pretty-printing", { NULL, 0 }, mi_cmd_enable_pretty_printing},

2
gdb/mi/mi-cmds.h
View File

@ -47,7 +47,9 @@ extern mi_cmd_argv_ftype mi_cmd_data_list_register_names;
extern mi_cmd_argv_ftype mi_cmd_data_list_register_values;
extern mi_cmd_argv_ftype mi_cmd_data_list_changed_registers;
extern mi_cmd_argv_ftype mi_cmd_data_read_memory;
extern mi_cmd_argv_ftype mi_cmd_data_read_memory_bytes;
extern mi_cmd_argv_ftype mi_cmd_data_write_memory;
extern mi_cmd_argv_ftype mi_cmd_data_write_memory_bytes;
extern mi_cmd_argv_ftype mi_cmd_data_write_register_values;
extern mi_cmd_argv_ftype mi_cmd_enable_timings;
extern mi_cmd_argv_ftype mi_cmd_env_cd;

127
gdb/mi/mi-main.c
View File

@ -1352,9 +1352,9 @@ mi_cmd_data_read_memory (char *command, char **argv, int argc)
/* Dispatch memory reads to the topmost target, not the flattened
current_target. */
nr_bytes = target_read_until_error (current_target.beneath,
TARGET_OBJECT_MEMORY, NULL, mbuf,
addr, total_bytes);
nr_bytes = target_read (current_target.beneath,
TARGET_OBJECT_MEMORY, NULL, mbuf,
addr, total_bytes);
if (nr_bytes <= 0)
error ("Unable to read memory.");
@ -1437,6 +1437,88 @@ mi_cmd_data_read_memory (char *command, char **argv, int argc)
do_cleanups (cleanups);
}
void
mi_cmd_data_read_memory_bytes (char *command, char **argv, int argc)
{
struct gdbarch *gdbarch = get_current_arch ();
struct cleanup *cleanups;
CORE_ADDR addr;
LONGEST length;
memory_read_result_s *read_result;
int ix;
VEC(memory_read_result_s) *result;
long offset = 0;
int optind = 0;
char *optarg;
enum opt
{
OFFSET_OPT
};
static struct mi_opt opts[] =
{
{"o", OFFSET_OPT, 1},
{ 0, 0, 0 }
};
while (1)
{
int opt = mi_getopt ("mi_cmd_data_read_memory_bytes", argc, argv, opts,
&optind, &optarg);
if (opt < 0)
break;
switch ((enum opt) opt)
{
case OFFSET_OPT:
offset = atol (optarg);
break;
}
}
argv += optind;
argc -= optind;
if (argc != 2)
error ("Usage: [ -o OFFSET ] ADDR LENGTH.");
addr = parse_and_eval_address (argv[0]) + offset;
length = atol (argv[1]);
result = read_memory_robust (current_target.beneath, addr, length);
cleanups = make_cleanup (free_memory_read_result_vector, result);
if (VEC_length (memory_read_result_s, result) == 0)
error ("Unable to read memory.");
make_cleanup_ui_out_list_begin_end (uiout, "memory");
for (ix = 0;
VEC_iterate (memory_read_result_s, result, ix, read_result);
++ix)
{
struct cleanup *t = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
char *data, *p;
int i;
ui_out_field_core_addr (uiout, "begin", gdbarch, read_result->begin);
ui_out_field_core_addr (uiout, "offset", gdbarch, read_result->begin
- addr);
ui_out_field_core_addr (uiout, "end", gdbarch, read_result->end);
data = xmalloc ((read_result->end - read_result->begin) * 2 + 1);
for (i = 0, p = data;
i < (read_result->end - read_result->begin);
++i, p += 2)
{
sprintf (p, "%02x", read_result->data[i]);
}
ui_out_field_string (uiout, "contents", data);
xfree (data);
do_cleanups (t);
}
do_cleanups (cleanups);
}
/* DATA-MEMORY-WRITE:
COLUMN_OFFSET: optional argument. Must be preceeded by '-o'. The
@ -1523,6 +1605,44 @@ mi_cmd_data_write_memory (char *command, char **argv, int argc)
do_cleanups (old_chain);
}
/* DATA-MEMORY-WRITE-RAW:
ADDR: start address
DATA: string of bytes to write at that address. */
void
mi_cmd_data_write_memory_bytes (char *command, char **argv, int argc)
{
CORE_ADDR addr;
char *cdata;
gdb_byte *data;
int len, r, i;
struct cleanup *back_to;
if (argc != 2)
error ("Usage: ADDR DATA.");
addr = parse_and_eval_address (argv[0]);
cdata = argv[1];
len = strlen (cdata)/2;
data = xmalloc (len);
back_to = make_cleanup (xfree, data);
for (i = 0; i < len; ++i)
{
int x;
sscanf (cdata + i * 2, "%02x", &x);
data[i] = (gdb_byte)x;
}
r = target_write_memory (addr, data, len);
if (r != 0)
error (_("Could not write memory"));
do_cleanups (back_to);
}
void
mi_cmd_enable_timings (char *command, char **argv, int argc)
{
@ -1557,6 +1677,7 @@ mi_cmd_list_features (char *command, char **argv, int argc)
ui_out_field_string (uiout, NULL, "frozen-varobjs");
ui_out_field_string (uiout, NULL, "pending-breakpoints");
ui_out_field_string (uiout, NULL, "thread-info");
ui_out_field_string (uiout, NULL, "data-read-memory-bytes");
#if HAVE_PYTHON
ui_out_field_string (uiout, NULL, "python");

247
gdb/target.c
View File

@ -1792,73 +1792,204 @@ target_read (struct target_ops *ops,
return len;
}
LONGEST
target_read_until_error (struct target_ops *ops,
enum target_object object,
const char *annex, gdb_byte *buf,
ULONGEST offset, LONGEST len)
{
LONGEST xfered = 0;
/** Assuming that the entire [begin, end) range of memory cannot be read,
try to read whatever subrange is possible to read.
The function results, in RESULT, either zero or one memory block.
If there's a readable subrange at the beginning, it is completely
read and returned. Any further readable subrange will not be read.
Otherwise, if there's a readable subrange at the end, it will be
completely read and returned. Any readable subranges before it (obviously,
not starting at the beginning), will be ignored. In other cases --
either no readable subrange, or readable subrange (s) that is neither
at the beginning, or end, nothing is returned.
The purpose of this function is to handle a read across a boundary of
accessible memory in a case when memory map is not available. The above
restrictions are fine for this case, but will give incorrect results if
the memory is 'patchy'. However, supporting 'patchy' memory would require
trying to read every single byte, and it seems unacceptable solution.
Explicit memory map is recommended for this case -- and
target_read_memory_robust will take care of reading multiple ranges then. */
static void
read_whatever_is_readable (struct target_ops *ops, ULONGEST begin, ULONGEST end,
VEC(memory_read_result_s) **result)
{
gdb_byte *buf = xmalloc (end-begin);
ULONGEST current_begin = begin;
ULONGEST current_end = end;
int forward;
memory_read_result_s r;
/* If we previously failed to read 1 byte, nothing can be done here. */
if (end - begin <= 1)
return;
/* Check that either first or the last byte is readable, and give up
if not. This heuristic is meant to permit reading accessible memory
at the boundary of accessible region. */
if (target_read_partial (ops, TARGET_OBJECT_MEMORY, NULL,
buf, begin, 1) == 1)
{
forward = 1;
++current_begin;
}
else if (target_read_partial (ops, TARGET_OBJECT_MEMORY, NULL,
buf + (end-begin) - 1, end - 1, 1) == 1)
{
forward = 0;
--current_end;
}
else
{
return;
}
/* Loop invariant is that the [current_begin, current_end) was previously
found to be not readable as a whole.
Note loop condition -- if the range has 1 byte, we can't divide the range
so there's no point trying further. */
while (current_end - current_begin > 1)
{
ULONGEST first_half_begin, first_half_end;
ULONGEST second_half_begin, second_half_end;
LONGEST xfer;
ULONGEST middle = current_begin + (current_end - current_begin)/2;
if (forward)
{
first_half_begin = current_begin;
first_half_end = middle;
second_half_begin = middle;
second_half_end = current_end;
}
else
{
first_half_begin = middle;
first_half_end = current_end;
second_half_begin = current_begin;
second_half_end = middle;
}
xfer = target_read (ops, TARGET_OBJECT_MEMORY, NULL,
buf + (first_half_begin - begin),
first_half_begin,
first_half_end - first_half_begin);
if (xfer == first_half_end - first_half_begin)
{
/* This half reads up fine. So, the error must be in the other half. */
current_begin = second_half_begin;
current_end = second_half_end;
}
else
{
/* This half is not readable. Because we've tried one byte, we
know some part of this half if actually redable. Go to the next
iteration to divide again and try to read.
We don't handle the other half, because this function only tries
to read a single readable subrange. */
current_begin = first_half_begin;
current_end = first_half_end;
}
}
if (forward)
{
/* The [begin, current_begin) range has been read. */
r.begin = begin;
r.end = current_begin;
r.data = buf;
}
else
{
/* The [current_end, end) range has been read. */
LONGEST rlen = end - current_end;
r.data = xmalloc (rlen);
memcpy (r.data, buf + current_end - begin, rlen);
r.begin = current_end;
r.end = end;
xfree (buf);
}
VEC_safe_push(memory_read_result_s, (*result), &r);
}
void
free_memory_read_result_vector (void *x)
{
VEC(memory_read_result_s) *v = x;
memory_read_result_s *current;
int ix;
for (ix = 0; VEC_iterate (memory_read_result_s, v, ix, current); ++ix)
{
xfree (current->data);
}
VEC_free (memory_read_result_s, v);
}
VEC(memory_read_result_s) *
read_memory_robust (struct target_ops *ops, ULONGEST offset, LONGEST len)
{
VEC(memory_read_result_s) *result = 0;
LONGEST xfered = 0;
while (xfered < len)
{
LONGEST xfer = target_read_partial (ops, object, annex,
(gdb_byte *) buf + xfered,
offset + xfered, len - xfered);
struct mem_region *region = lookup_mem_region (offset + xfered);
LONGEST rlen;
/* Call an observer, notifying them of the xfer progress? */
if (xfer == 0)
return xfered;
if (xfer < 0)
/* If there is no explicit region, a fake one should be created. */
gdb_assert (region);
if (region->hi == 0)
rlen = len - xfered;
else
rlen = region->hi - offset;
if (region->attrib.mode == MEM_NONE || region->attrib.mode == MEM_WO)
{
/* We've got an error. Try to read in smaller blocks. */
ULONGEST start = offset + xfered;
ULONGEST remaining = len - xfered;
ULONGEST half;
/* If an attempt was made to read a random memory address,
it's likely that the very first byte is not accessible.
Try reading the first byte, to avoid doing log N tries
below. */
xfer = target_read_partial (ops, object, annex,
(gdb_byte *) buf + xfered, start, 1);
if (xfer <= 0)
return xfered;
start += 1;
remaining -= 1;
half = remaining/2;
while (half > 0)
{
xfer = target_read_partial (ops, object, annex,
(gdb_byte *) buf + xfered,
start, half);
if (xfer == 0)
return xfered;
if (xfer < 0)
{
remaining = half;
}
else
{
/* We have successfully read the first half. So, the
error must be in the second half. Adjust start and
remaining to point at the second half. */
xfered += xfer;
start += xfer;
remaining -= xfer;
}
half = remaining/2;
}
return xfered;
/* Cannot read this region. Note that we can end up here only
if the region is explicitly marked inaccessible, or
'inaccessible-by-default' is in effect. */
xfered += rlen;
}
else
{
LONGEST to_read = min (len - xfered, rlen);
gdb_byte *buffer = (gdb_byte *)xmalloc (to_read);
LONGEST xfer = target_read (ops, TARGET_OBJECT_MEMORY, NULL,
(gdb_byte *) buffer,
offset + xfered, to_read);
/* Call an observer, notifying them of the xfer progress? */
if (xfer <= 0)
{
/* Got an error reading full chunk. See if maybe we can read
some subrange. */
xfree (buffer);
read_whatever_is_readable (ops, offset + xfered, offset + xfered + to_read, &result);
xfered += to_read;
}
else
{
struct memory_read_result r;
r.data = buffer;
r.begin = offset + xfered;
r.end = r.begin + xfer;
VEC_safe_push (memory_read_result_s, result, &r);
xfered += xfer;
}
QUIT;
}
xfered += xfer;
QUIT;
}
return len;
return result;
}
/* An alternative to target_write with progress callbacks. */
LONGEST

21
gdb/target.h
View File

@ -299,10 +299,23 @@ extern LONGEST target_read (struct target_ops *ops,
const char *annex, gdb_byte *buf,
ULONGEST offset, LONGEST len);
extern LONGEST target_read_until_error (struct target_ops *ops,
enum target_object object,
const char *annex, gdb_byte *buf,
ULONGEST offset, LONGEST len);
struct memory_read_result
{
/* First address that was read. */
ULONGEST begin;
/* Past-the-end address. */
ULONGEST end;
/* The data. */
gdb_byte *data;
};
typedef struct memory_read_result memory_read_result_s;
DEF_VEC_O(memory_read_result_s);
extern void free_memory_read_result_vector (void *);
extern VEC(memory_read_result_s)* read_memory_robust (struct target_ops *ops,
ULONGEST offset,
LONGEST len);
extern LONGEST target_write (struct target_ops *ops,
enum target_object object,