/*
* This file is part of ltrace.
* Copyright (C) 2012,2013,2014 Petr Machata, Red Hat Inc.
* Copyright (C) 2009 Juan Cespedes
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#ifndef BREAKPOINT_H
#define BREAKPOINT_H
/* XXX This is currently a very weak abstraction. We would like to
* much expand this to allow things like breakpoints on SDT probes and
* such.
*
* In particular, we would like to add a tracepoint abstraction.
* Tracepoint is a traceable feature--e.g. an exact address, a DWARF
* symbol, an ELF symbol, a PLT entry, or an SDT probe. Tracepoints
* are named and the user can configure which of them he wants to
* enable. Realized tracepoints enable breakpoints, which are a
* low-level realization of high-level tracepoint.
*
* Service breakpoints like the handling of dlopen would be a
* low-level breakpoint, likely without tracepoint attached.
*
* So that's for sometimes.
*/
#include "sysdep.h"
#include "library.h"
#include "forward.h"
struct bp_callbacks {
void (*on_hit)(struct breakpoint *bp, struct process *proc);
void (*on_continue)(struct breakpoint *bp, struct process *proc);
void (*on_install)(struct breakpoint *bp, struct process *proc);
void (*on_retract)(struct breakpoint *bp, struct process *proc);
/* Create a new breakpoint that should handle return from the
* function. BP is the breakpoint that was just hit and for
* which we wish to find the corresponding return breakpoint.
* This returns 0 on success (in which case *RET will have
* been initialized to desired breakpoint object, or NULL if
* none is necessary) or a negative value on failure. */
int (*get_return_bp)(struct breakpoint **ret,
struct breakpoint *bp, struct process *proc);
};
struct breakpoint {
struct bp_callbacks *cbs;
struct library_symbol *libsym;
void *addr;
unsigned char orig_value[BREAKPOINT_LENGTH];
int enabled;
struct arch_breakpoint_data arch;
struct os_breakpoint_data os;
};
/* Call ON_HIT handler of BP, if any is set. */
void breakpoint_on_hit(struct breakpoint *bp, struct process *proc);
/* Call ON_CONTINUE handler of BP. If none is set, call
* continue_after_breakpoint. */
void breakpoint_on_continue(struct breakpoint *bp, struct process *proc);
/* Call ON_RETRACT handler of BP, if any is set. This should be
* called before the breakpoints are destroyed. The reason for a
* separate interface is that breakpoint_destroy has to be callable
* without PROC. ON_DISABLE might be useful as well, but that would
* be called every time we disable the breakpoint, which is too often
* (a breakpoint has to be disabled every time that we need to execute
* the instruction underneath it). */
void breakpoint_on_retract(struct breakpoint *bp, struct process *proc);
/* Call ON_INSTALL handler of BP, if any is set. This should be
* called after the breakpoint is enabled for the first time, not
* every time it's enabled (such as after stepping over a site of a
* temporarily disabled breakpoint). */
void breakpoint_on_install(struct breakpoint *bp, struct process *proc);
/* Call GET_RETURN_BP handler of BP, if any is set. If none is set,
* call CREATE_DEFAULT_RETURN_BP to obtain one. */
int breakpoint_get_return_bp(struct breakpoint **ret,
struct breakpoint *bp, struct process *proc);
/* Initialize a breakpoint structure. That doesn't actually realize
* the breakpoint. The breakpoint is initially assumed to be
* disabled. orig_value has to be set separately. CBS may be
* NULL. */
int breakpoint_init(struct breakpoint *bp, struct process *proc,
arch_addr_t addr, struct library_symbol *libsym);
/* Make a clone of breakpoint BP into the area of memory pointed to by
* RETP. Symbols of cloned breakpoint are looked up in NEW_PROC.
* Returns 0 on success or a negative value on failure. */
int breakpoint_clone(struct breakpoint *retp, struct process *new_proc,
struct breakpoint *bp);
/* Set callbacks. If CBS is non-NULL, then BP->cbs shall be NULL. */
void breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs);
/* Destroy a breakpoint structure. */
void breakpoint_destroy(struct breakpoint *bp);
/* Call enable_breakpoint the first time it's called. Returns 0 on
* success and a negative value on failure. */
int breakpoint_turn_on(struct breakpoint *bp, struct process *proc);
/* Call disable_breakpoint when turned off the same number of times
* that it was turned on. Returns 0 on success and a negative value
* on failure. */
int breakpoint_turn_off(struct breakpoint *bp, struct process *proc);
/* Allocate and initialize a default return breakpoint. Returns NULL
* on failure. */
struct breakpoint *create_default_return_bp(struct process *proc);
/* This allocates and initializes new breakpoint at ADDR, then calls
* INSERT_BREAKPOINT. Returns the new breakpoint or NULL if there are
* errors. */
struct breakpoint *insert_breakpoint_at(struct process *proc, arch_addr_t addr,
struct library_symbol *libsym);
/* Check if there is a breakpoint on this address already. If yes,
* return that breakpoint instead (BP was not added). If no, try to
* PROC_ADD_BREAKPOINT and BREAKPOINT_TURN_ON. If it all works,
* return BP. Otherwise return NULL. */
struct breakpoint *insert_breakpoint(struct process *proc,
struct breakpoint *bp);
/* Name of a symbol associated with BP. May be NULL. */
const char *breakpoint_name(const struct breakpoint *bp);
/* A library that this breakpoint comes from. May be NULL. */
struct library *breakpoint_library(const struct breakpoint *bp);
/* Again, this seems to be several interfaces rolled into one:
* - breakpoint_disable
* - proc_remove_breakpoint
* - breakpoint_destroy
* XXX */
void delete_breakpoint_at(struct process *proc, void *addr);
int delete_breakpoint(struct process *proc, struct breakpoint *bp);
/* XXX some of the following belongs to proc.h/proc.c. */
struct breakpoint *address2bpstruct(struct process *proc, void *addr);
void disable_all_breakpoints(struct process *proc);
int breakpoints_init(struct process *proc);
#endif /* BREAKPOINT_H */