breakpoint.h revision 02a796e5e49c147982020c78b0066930e979f3e4 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012, 2013 Petr Machata, Red Hat Inc.
4 * Copyright (C) 2009 Juan Cespedes
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21
22#ifndef BREAKPOINT_H
23#define BREAKPOINT_H
24
25/* XXX This is currently a very weak abstraction.  We would like to
26 * much expand this to allow things like breakpoints on SDT probes and
27 * such.
28 *
29 * In particular, we would like to add a tracepoint abstraction.
30 * Tracepoint is a traceable feature--e.g. an exact address, a DWARF
31 * symbol, an ELF symbol, a PLT entry, or an SDT probe.  Tracepoints
32 * are named and the user can configure which of them he wants to
33 * enable.  Realized tracepoints enable breakpoints, which are a
34 * low-level realization of high-level tracepoint.
35 *
36 * Service breakpoints like the handling of dlopen would be a
37 * low-level breakpoint, likely without tracepoint attached.
38 *
39 * So that's for sometimes.
40 */
41
42#include "sysdep.h"
43#include "library.h"
44#include "forward.h"
45
46struct bp_callbacks {
47	void (*on_hit)(struct breakpoint *bp, struct process *proc);
48	void (*on_continue)(struct breakpoint *bp, struct process *proc);
49	void (*on_retract)(struct breakpoint *bp, struct process *proc);
50};
51
52struct breakpoint {
53	struct bp_callbacks *cbs;
54	struct library_symbol *libsym;
55	void *addr;
56	unsigned char orig_value[BREAKPOINT_LENGTH];
57	int enabled;
58	struct arch_breakpoint_data arch;
59};
60
61/* Call on-hit handler of BP, if any is set.  */
62void breakpoint_on_hit(struct breakpoint *bp, struct process *proc);
63
64/* Call on-continue handler of BP.  If none is set, call
65 * continue_after_breakpoint.  */
66void breakpoint_on_continue(struct breakpoint *bp, struct process *proc);
67
68/* Call on-retract handler of BP, if any is set.  This should be
69 * called before the breakpoints are destroyed.  The reason for a
70 * separate interface is that breakpoint_destroy has to be callable
71 * without PROC.  ON_DISABLE might be useful as well, but that would
72 * be called every time we disable the breakpoint, which is too often
73 * (a breakpoint has to be disabled every time that we need to execute
74 * the instruction underneath it).  */
75void breakpoint_on_retract(struct breakpoint *bp, struct process *proc);
76
77/* Initialize a breakpoint structure.  That doesn't actually realize
78 * the breakpoint.  The breakpoint is initially assumed to be
79 * disabled.  orig_value has to be set separately.  CBS may be
80 * NULL.  */
81int breakpoint_init(struct breakpoint *bp, struct process *proc,
82		    arch_addr_t addr, struct library_symbol *libsym);
83
84/* Make a clone of breakpoint BP into the area of memory pointed to by
85 * RETP.  Symbols of cloned breakpoint are looked up in NEW_PROC.
86 * Returns 0 on success or a negative value on failure.  */
87int breakpoint_clone(struct breakpoint *retp, struct process *new_proc,
88		     struct breakpoint *bp);
89
90/* Set callbacks.  If CBS is non-NULL, then BP->cbs shall be NULL.  */
91void breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs);
92
93/* Destroy a breakpoint structure.   */
94void breakpoint_destroy(struct breakpoint *bp);
95
96/* Call enable_breakpoint the first time it's called.  Returns 0 on
97 * success and a negative value on failure.  */
98int breakpoint_turn_on(struct breakpoint *bp, struct process *proc);
99
100/* Call disable_breakpoint when turned off the same number of times
101 * that it was turned on.  Returns 0 on success and a negative value
102 * on failure.  */
103int breakpoint_turn_off(struct breakpoint *bp, struct process *proc);
104
105/* Utility function that does what typically needs to be done when a
106 * breakpoint is to be inserted.  It checks whether there is another
107 * breakpoint in PROC->LEADER for given ADDR.  If not, it allocates
108 * memory for a new breakpoint on the heap, initializes it, and calls
109 * PROC_ADD_BREAKPOINT to add the newly-created breakpoint.  For newly
110 * added as well as preexisting breakpoints, it then calls
111 * BREAKPOINT_TURN_ON.  If anything fails, it cleans up and returns
112 * NULL.  Otherwise it returns the breakpoint for ADDR.  */
113struct breakpoint *insert_breakpoint_at(struct process *proc, arch_addr_t addr,
114					struct library_symbol *libsym);
115
116/* Name of a symbol associated with BP.  May be NULL.  */
117const char *breakpoint_name(const struct breakpoint *bp);
118
119/* A library that this breakpoint comes from.  May be NULL.  */
120struct library *breakpoint_library(const struct breakpoint *bp);
121
122/* Again, this seems to be several interfaces rolled into one:
123 *  - breakpoint_disable
124 *  - proc_remove_breakpoint
125 *  - breakpoint_destroy
126 * XXX */
127void delete_breakpoint(struct process *proc, void *addr);
128
129/* XXX some of the following belongs to proc.h/proc.c.  */
130struct breakpoint *address2bpstruct(struct process *proc, void *addr);
131void enable_all_breakpoints(struct process *proc);
132void disable_all_breakpoints(struct process *proc);
133int breakpoints_init(struct process *proc);
134
135#endif /* BREAKPOINT_H */
136