binutils-gdb/gdbserver/ax.h
Andrew Burgess 424646edf4 gdbserver: handle all eval_result_type values in tracepoint.cc
It was pointed out[1] that after this commit:

  commit 3812b38d8d
  Date:   Thu Oct 20 11:14:33 2022 +0100

      gdbserver: allow agent expressions to fail with invalid memory access

Now that agent expressions might fail with the error
expr_eval_invalid_memory_access, we might overflow the
eval_result_names array in tracepoint.cc.  This is because the
eval_result_names array does not include a string for either
expr_eval_invalid_goto or expr_eval_invalid_memory_access.

I don't know if having expr_eval_invalid_goto missing is also a
problem, but it feels like eval_result_names should just include a
string for every possible error.

I could just add two more strings into the array, but I figure that a
more robust solution will be to move all of the error types, and their
associated strings, into a new ax-result-types.def file, and to then
include this file in both ax.h and tracepoint.cc in order to build
the enum eval_result_type and the eval_result_names string array.
Doing this means it is impossible to have a missing error string in
the future.

[1] https://inbox.sourceware.org/gdb-patches/01059f8a-0e59-55b5-f530-190c26df5ba3@palves.net/

Approved-By: Pedro Alves <pedro@palves.net>
2023-07-10 14:42:54 +01:00

140 lines
4.4 KiB
C

/* Data structures and functions associated with agent expressions in GDB.
Copyright (C) 2009-2023 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 GDBSERVER_AX_H
#define GDBSERVER_AX_H
#include "regcache.h"
#ifdef IN_PROCESS_AGENT
#include "gdbsupport/agent.h"
#define debug_threads debug_agent
#endif
struct traceframe;
/* Enumeration of the different kinds of things that can happen during
agent expression evaluation. */
enum eval_result_type
{
#define AX_RESULT_TYPE(ENUM,STR) ENUM,
#include "ax-result-types.def"
#undef AX_RESULT_TYPE
};
struct agent_expr
{
int length;
unsigned char *bytes;
};
#ifndef IN_PROCESS_AGENT
/* The packet form of an agent expression consists of an 'X', number
of bytes in expression, a comma, and then the bytes. */
struct agent_expr *gdb_parse_agent_expr (const char **actparm);
/* Release an agent expression. */
void gdb_free_agent_expr (struct agent_expr *aexpr);
/* Convert the bytes of an agent expression back into hex digits, so
they can be printed or uploaded. This allocates the buffer,
callers should free when they are done with it. */
char *gdb_unparse_agent_expr (struct agent_expr *aexpr);
void emit_prologue (void);
void emit_epilogue (void);
enum eval_result_type compile_bytecodes (struct agent_expr *aexpr);
#endif
/* The context when evaluating agent expression. */
struct eval_agent_expr_context
{
/* The registers when evaluating agent expression. */
struct regcache *regcache;
/* The traceframe, if any, when evaluating agent expression. */
struct traceframe *tframe;
/* The tracepoint, if any, when evaluating agent expression. */
struct tracepoint *tpoint;
};
enum eval_result_type
gdb_eval_agent_expr (struct eval_agent_expr_context *ctx,
struct agent_expr *aexpr,
ULONGEST *rslt);
/* Bytecode compilation function vector. */
struct emit_ops
{
void (*emit_prologue) (void);
void (*emit_epilogue) (void);
void (*emit_add) (void);
void (*emit_sub) (void);
void (*emit_mul) (void);
void (*emit_lsh) (void);
void (*emit_rsh_signed) (void);
void (*emit_rsh_unsigned) (void);
void (*emit_ext) (int arg);
void (*emit_log_not) (void);
void (*emit_bit_and) (void);
void (*emit_bit_or) (void);
void (*emit_bit_xor) (void);
void (*emit_bit_not) (void);
void (*emit_equal) (void);
void (*emit_less_signed) (void);
void (*emit_less_unsigned) (void);
void (*emit_ref) (int size);
void (*emit_if_goto) (int *offset_p, int *size_p);
void (*emit_goto) (int *offset_p, int *size_p);
void (*write_goto_address) (CORE_ADDR from, CORE_ADDR to, int size);
void (*emit_const) (LONGEST num);
void (*emit_call) (CORE_ADDR fn);
void (*emit_reg) (int reg);
void (*emit_pop) (void);
void (*emit_stack_flush) (void);
void (*emit_zero_ext) (int arg);
void (*emit_swap) (void);
void (*emit_stack_adjust) (int n);
/* Emit code for a generic function that takes one fixed integer
argument and returns a 64-bit int (for instance, tsv getter). */
void (*emit_int_call_1) (CORE_ADDR fn, int arg1);
/* Emit code for a generic function that takes one fixed integer
argument and a 64-bit int from the top of the stack, and returns
nothing (for instance, tsv setter). */
void (*emit_void_call_2) (CORE_ADDR fn, int arg1);
/* Emit code specialized for common combinations of compare followed
by a goto. */
void (*emit_eq_goto) (int *offset_p, int *size_p);
void (*emit_ne_goto) (int *offset_p, int *size_p);
void (*emit_lt_goto) (int *offset_p, int *size_p);
void (*emit_le_goto) (int *offset_p, int *size_p);
void (*emit_gt_goto) (int *offset_p, int *size_p);
void (*emit_ge_goto) (int *offset_p, int *size_p);
};
extern CORE_ADDR current_insn_ptr;
extern int emit_error;
#endif /* GDBSERVER_AX_H */