old-cross-binutils/gdb/gdbcore.h
Yao Qi 9b409511d0 Return target_xfer_status in to_xfer_partial
This patch does the conversion of to_xfer_partial from

    LONGEST (*to_xfer_partial) (struct target_ops *ops,
				enum target_object object, const char *annex,
				gdb_byte *readbuf, const gdb_byte *writebuf,
				ULONGEST offset, ULONGEST len);

to

    enum target_xfer_status (*to_xfer_partial) (struct target_ops *ops,
				enum target_object object, const char *annex,
				gdb_byte *readbuf, const gdb_byte *writebuf,
				ULONGEST offset, ULONGEST len, ULONGEST *xfered_len);

It changes to_xfer_partial return the transfer status and the transfered
length by *XFERED_LEN.  Generally, the return status has three stats,

 - TARGET_XFER_OK,
 - TARGET_XFER_EOF,
 - TARGET_XFER_E_XXXX,

See the comments to them in 'enum target_xfer_status'.  Note that
Pedro suggested not name TARGET_XFER_DONE, as it is confusing,
compared with "TARGET_XFER_OK".  We finally name it TARGET_XFER_EOF.

With this change, GDB core can handle unavailable data in a convenient
way.

The rationale behind this change was mentioned here
https://sourceware.org/ml/gdb-patches/2013-10/msg00761.html

Consider an object/value like this:

  0          100      150        200           512
  DDDDDDDDDDDxxxxxxxxxDDDDDD...DDIIIIIIIIIIII..III

where D is valid data, and xxx is unavailable data, and I is beyond
the end of the object (Invalid).  Currently, if we start the
xfer at 0, requesting, say 512 bytes, we'll first get back 100 bytes.
The xfer machinery then retries fetching [100,512), and gets back
TARGET_XFER_E_UNAVAILABLE.  That's sufficient when you're either
interested in either having the whole of the 512 bytes available,
or erroring out.  But, in this scenario, we're interested in
the data at [150,512).  The problem is that the last
TARGET_XFER_E_UNAVAILABLE gives us no indication where to
start the read next.  We'd need something like:

get me [0,512) >>>
     <<< here's [0,100), *xfered_len is 100, returns TARGET_XFER_OK

get me [100,512)  >>> (**1)
     <<< [100,150) is unavailable, *xfered_len is 50, return TARGET_XFER_E_UNAVAILABLE.

get me [150,512) >>>
     <<< here's [150,200), *xfered_len is 50, return TARGET_XFER_OK.

get me [200,512) >>>
     <<< no more data, return TARGET_XFER_EOF.

This naturally implies pushing down the decision of whether
to return TARGET_XFER_E_UNAVAILABLE or something else
down to the target.  (Which kinds of leads back to tfile
itself reading from RO memory from file (though we could
export a function in exec.c for that that tfile delegates to,
instead of re-adding the old code).

Beside this change, we also add a macro TARGET_XFER_STATUS_ERROR_P to
check whether a status is an error or not, to stop using "status < 0".
This patch also eliminates the comparison between status and 0.

No target implementations to to_xfer_partial adapts this new
interface.  The interface still behaves as before.

gdb:

2014-02-11  Yao Qi  <yao@codesourcery.com>

	* target.h (enum target_xfer_error): Rename to ...
	(enum target_xfer_status): ... it.  New.  All users updated.
	(enum target_xfer_status) <TARGET_XFER_OK>, <TARGET_XFER_EOF>:
	New.
	(TARGET_XFER_STATUS_ERROR_P): New macro.
	(target_xfer_error_to_string): Remove declaration.
	(target_xfer_status_to_string): Declare.
	(target_xfer_partial_ftype): Adjust it.
	(struct target_ops) <to_xfer_partial>: Return
	target_xfer_status.  Add argument xfered_len.  Update
	comments.
	* target.c (target_xfer_error_to_string): Rename to ...
	(target_xfer_status_to_string): ... it.  New.  All callers
	updated.
	(target_read_live_memory): Likewise.  Call target_xfer_partial
	instead of target_read.
	(memory_xfer_live_readonly_partial): Return
	target_xfer_status.  Add argument xfered_len.
	(raw_memory_xfer_partial): Likewise.
	(memory_xfer_partial_1): Likewise.
	(memory_xfer_partial): Likewise.
	(target_xfer_partial): Likewise.  Check *XFERED_LEN is set
	properly.  Update debug message.
	(default_xfer_partial, current_xfer_partial): Likewise.
	(target_write_partial): Likewise.
	(target_read_partial): Likewise.  All callers updated.
	(read_whatever_is_readable): Likewise.
	(target_write_with_progress): Likewise.
	(target_read_alloc_1): Likewise.

	* aix-thread.c (aix_thread_xfer_partial): Likewise.
	* auxv.c (procfs_xfer_auxv): Likewise.
	(ld_so_xfer_auxv, memory_xfer_auxv): Likewise.
	* bfd-target.c (target_bfd_xfer_partial): Likewise.
	* bsd-kvm.c (bsd_kvm_xfer_partial): Likewise.
	* bsd-uthread.c (bsd_uthread_xfer_partia): Likewise.
	* corefile.c (read_memory): Adjust.
	* corelow.c (core_xfer_partial): Likewise.
	* ctf.c (ctf_xfer_partial): Likewise.
	* darwin-nat.c (darwin_read_dyld_info): Likewise.  All callers
	updated.
	(darwin_xfer_partial): Likewise.
	* exec.c (section_table_xfer_memory_partial): Likewise.  All
	callers updated.
	(exec_xfer_partial): Likewise.
	* exec.h (section_table_xfer_memory_partial): Update
	declaration.
	* gnu-nat.c (gnu_xfer_memory): Likewise.  Assert 'res' is not
	negative.
	(gnu_xfer_partial): Likewise.
	* ia64-hpux-nat.c (ia64_hpux_xfer_memory_no_bs): Likewise.
	(ia64_hpux_xfer_memory, ia64_hpux_xfer_uregs): Likewise.
	(ia64_hpux_xfer_solib_got): Likewise.
	* inf-ptrace.c (inf_ptrace_xfer_partial): Likewise.  Change
	type of 'partial_len' to ULONGEST.
	* inf-ttrace.c (inf_ttrace_xfer_partial): Likewise.
	* linux-nat.c (linux_xfer_siginfo ): Likewise.
	(linux_nat_xfer_partial): Likewise.
	(linux_proc_xfer_partial, linux_xfer_partial): Likewise.
	(linux_proc_xfer_spu, linux_nat_xfer_osdata): Likewise.
	* monitor.c (monitor_xfer_memory): Likewise.
	(monitor_xfer_partial): Likewise.
	* procfs.c (procfs_xfer_partial): Likewise.
	* record-btrace.c (record_btrace_xfer_partial): Likewise.
	* record-full.c (record_full_xfer_partial): Likewise.
	(record_full_core_xfer_partial): Likewise.
	* remote-sim.c (gdbsim_xfer_memory): Likewise.
	(gdbsim_xfer_partial): Likewise.
	* remote.c (remote_write_bytes_aux): Likewise.  All callers
	updated.
	(remote_write_bytes, remote_read_bytes): Likewise.  All
	callers updated.
	(remote_flash_erase): Likewise.  All callers updated.
	(remote_write_qxfer): Likewise.  All callers updated.
	(remote_read_qxfer): Likewise.  All callers updated.
	(remote_xfer_partial): Likewise.
	* rs6000-nat.c (rs6000_xfer_partial): Likewise.
	(rs6000_xfer_shared_libraries): Likewise.
	* sol-thread.c (sol_thread_xfer_partial): Likewise.
	(sol_thread_xfer_partial): Likewise.
	* sparc-nat.c (sparc_xfer_wcookie): Likewise.
	(sparc_xfer_partial): Likewise.
	* spu-linux-nat.c (spu_proc_xfer_spu): Likewise.  All callers
	updated.
	(spu_xfer_partial): Likewise.
	* spu-multiarch.c (spu_xfer_partial): Likewise.
	* tracepoint.c (tfile_xfer_partial): Likewise.
	* windows-nat.c (windows_xfer_memory): Likewise.
	(windows_xfer_shared_libraries): Likewise.
	(windows_xfer_partial): Likewise.
	* valprint.c: Replace 'target_xfer_error' with
	'target_xfer_status' in comments.
2014-02-11 14:20:33 +08:00

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/* Machine independent variables that describe the core file under GDB.
Copyright (C) 1986-2014 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/>. */
/* Interface routines for core, executable, etc. */
#if !defined (GDBCORE_H)
#define GDBCORE_H 1
struct type;
struct regcache;
#include "bfd.h"
#include "exec.h"
#include "target.h"
/* Return the name of the executable file as a string.
ERR nonzero means get error if there is none specified;
otherwise return 0 in that case. */
extern char *get_exec_file (int err);
/* Nonzero if there is a core file. */
extern int have_core_file_p (void);
/* Report a memory error with error(). */
extern void memory_error (enum target_xfer_status status, CORE_ADDR memaddr);
/* The string 'memory_error' would use as exception message. Space
for the result is malloc'd, caller must free. */
extern char *memory_error_message (enum target_xfer_status err,
struct gdbarch *gdbarch, CORE_ADDR memaddr);
/* Like target_read_memory, but report an error if can't read. */
extern void read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len);
/* Like target_read_stack, but report an error if can't read. */
extern void read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len);
/* Like target_read_code, but report an error if can't read. */
extern void read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len);
/* Read an integer from debugged memory, given address and number of
bytes. */
extern LONGEST read_memory_integer (CORE_ADDR memaddr,
int len, enum bfd_endian byte_order);
extern int safe_read_memory_integer (CORE_ADDR memaddr, int len,
enum bfd_endian byte_order,
LONGEST *return_value);
/* Read an unsigned integer from debugged memory, given address and
number of bytes. */
extern ULONGEST read_memory_unsigned_integer (CORE_ADDR memaddr,
int len,
enum bfd_endian byte_order);
/* Read an integer from debugged code memory, given address,
number of bytes, and byte order for code. */
extern LONGEST read_code_integer (CORE_ADDR memaddr, int len,
enum bfd_endian byte_order);
/* Read an unsigned integer from debugged code memory, given address,
number of bytes, and byte order for code. */
extern ULONGEST read_code_unsigned_integer (CORE_ADDR memaddr,
int len,
enum bfd_endian byte_order);
/* Read a null-terminated string from the debuggee's memory, given
address, a buffer into which to place the string, and the maximum
available space. */
extern void read_memory_string (CORE_ADDR, char *, int);
/* Read the pointer of type TYPE at ADDR, and return the address it
represents. */
CORE_ADDR read_memory_typed_address (CORE_ADDR addr, struct type *type);
/* This takes a char *, not void *. This is probably right, because
passing in an int * or whatever is wrong with respect to
byteswapping, alignment, different sizes for host vs. target types,
etc. */
extern void write_memory (CORE_ADDR memaddr, const gdb_byte *myaddr,
ssize_t len);
/* Same as write_memory, but notify 'memory_changed' observers. */
extern void write_memory_with_notification (CORE_ADDR memaddr,
const bfd_byte *myaddr,
ssize_t len);
/* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer. */
extern void write_memory_unsigned_integer (CORE_ADDR addr, int len,
enum bfd_endian byte_order,
ULONGEST value);
/* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer. */
extern void write_memory_signed_integer (CORE_ADDR addr, int len,
enum bfd_endian byte_order,
LONGEST value);
/* Hook for `exec_file_command' command to call. */
extern void (*deprecated_exec_file_display_hook) (char *filename);
/* Hook for "file_command", which is more useful than above
(because it is invoked AFTER symbols are read, not before). */
extern void (*deprecated_file_changed_hook) (char *filename);
extern void specify_exec_file_hook (void (*hook) (char *filename));
/* Binary File Diddler for the core file. */
extern bfd *core_bfd;
extern struct target_ops *core_target;
/* Whether to open exec and core files read-only or read-write. */
extern int write_files;
extern void core_file_command (char *filename, int from_tty);
extern void exec_file_attach (char *filename, int from_tty);
extern void exec_file_clear (int from_tty);
extern void validate_files (void);
/* The current default bfd target. */
extern char *gnutarget;
extern void set_gnutarget (char *);
/* Structure to keep track of core register reading functions for
various core file types. */
struct core_fns
{
/* BFD flavour that a core file handler is prepared to read. This
can be used by the handler's core tasting function as a first
level filter to reject BFD's that don't have the right
flavour. */
enum bfd_flavour core_flavour;
/* Core file handler function to call to recognize corefile
formats that BFD rejects. Some core file format just don't fit
into the BFD model, or may require other resources to identify
them, that simply aren't available to BFD (such as symbols from
another file). Returns nonzero if the handler recognizes the
format, zero otherwise. */
int (*check_format) (bfd *);
/* Core file handler function to call to ask if it can handle a
given core file format or not. Returns zero if it can't,
nonzero otherwise. */
int (*core_sniffer) (struct core_fns *, bfd *);
/* Extract the register values out of the core file and supply them
into REGCACHE.
CORE_REG_SECT points to the register values themselves, read into
memory.
CORE_REG_SIZE is the size of that area.
WHICH says which set of registers we are handling:
0 --- integer registers
2 --- floating-point registers, on machines where they are
discontiguous
3 --- extended floating-point registers, on machines where
these are present in yet a third area. (GNU/Linux uses
this to get at the SSE registers.)
REG_ADDR is the offset from u.u_ar0 to the register values relative to
core_reg_sect. This is used with old-fashioned core files to locate the
registers in a large upage-plus-stack ".reg" section. Original upage
address X is at location core_reg_sect+x+reg_addr. */
void (*core_read_registers) (struct regcache *regcache,
char *core_reg_sect,
unsigned core_reg_size,
int which, CORE_ADDR reg_addr);
/* Finds the next struct core_fns. They are allocated and
initialized in whatever module implements the functions pointed
to; an initializer calls deprecated_add_core_fns to add them to
the global chain. */
struct core_fns *next;
};
/* NOTE: cagney/2004-04-05: Replaced by "regset.h" and
regset_from_core_section(). */
extern void deprecated_add_core_fns (struct core_fns *cf);
extern int default_core_sniffer (struct core_fns *cf, bfd * abfd);
extern int default_check_format (bfd * abfd);
#endif /* !defined (GDBCORE_H) */