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/*
* This file is part of ltrace.
* Copyright (C) 2012 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.
*
* Tracepoints are provided by the main binary as well as by any
* opened libraries: every time an ELF file is mapped into the address
* space, a new set of tracepoints is extracted, and filtered
* according to user settings. Those tracepoints that are left are
* then realized, and the tracing starts.
*
* A scheme like this would take care of gradually introducing
* breakpoints when the library is mapped, and therefore ready, and
* would avoid certain hacks. For example on PPC64, we don't actually
* add breakpoints to PLT. Instead, we read the PLT (which contains
* addresses, not code), to figure out where to put the breakpoints.
* In prelinked code, that address is non-zero, and points to an
* address that's not yet mapped. ptrace then fails when we try to
* add the breakpoint.
*
* Ideally, return breakpoints would be just a special kind of
* tracepoint that has attached some magic. Or a feature of a
* 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"
struct Process;
struct breakpoint;
struct bp_callbacks {
void (*on_hit) (struct breakpoint *bp, struct Process *proc);
void (*on_continue) (struct breakpoint *bp, struct Process *proc);
void (*on_destroy) (struct breakpoint *bp);
};
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;
};
/* Call on-hit handler of BP, if any is set. */
void breakpoint_on_hit(struct breakpoint *bp, struct Process *proc);
/* Call on-reenable handler of BP. If none is set, call
* continue_after_breakpoint. */
void breakpoint_on_continue(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,
target_address_t addr, struct library_symbol *libsym);
/* Set callbacks. If CBS is non-NULL, then BP->cbs shall be NULL. */
void breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs);
/* XXX this is currently not called anywhere. */
void breakpoint_destroy(struct breakpoint *bp);
/* This is actually three functions rolled in one:
* - breakpoint_init
* - proc_breakpoint_insert
* - breakpoint_enable
* XXX I think it should be broken up somehow. */
struct breakpoint *insert_breakpoint(struct Process *proc, void *addr,
struct library_symbol *libsym);
/* Name of a symbol associated with BP. May be NULL. */
const char *breakpoint_name(const struct breakpoint *bp);
/* Again, this seems to be several interfaces rolled into one:
* - breakpoint_disable
* - proc_breakpoint_remove
* - breakpoint_destroy
* XXX */
void delete_breakpoint(struct Process *proc, void *addr);
/* XXX some of the following belongs to proc.h/proc.c. */
struct breakpoint *address2bpstruct(struct Process *proc, void *addr);
void enable_all_breakpoints(struct Process *proc);
void disable_all_breakpoints(struct Process *proc);
int breakpoints_init(struct Process *proc, int enable);
#endif /* BREAKPOINT_H */
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