breakpoint.h revision 0c3377e8d516bbb8b053ca92a2bb68dc65a64288 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012 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
45struct Process;
46struct breakpoint;
47
48struct bp_callbacks {
49	void (*on_hit)(struct breakpoint *bp, struct Process *proc);
50	void (*on_continue)(struct breakpoint *bp, struct Process *proc);
51};
52
53struct breakpoint {
54	struct bp_callbacks *cbs;
55	struct library_symbol *libsym;
56	void *addr;
57	unsigned char orig_value[BREAKPOINT_LENGTH];
58	int enabled;
59	struct arch_breakpoint_data arch;
60};
61
62/* Call on-hit handler of BP, if any is set.  */
63void breakpoint_on_hit(struct breakpoint *bp, struct Process *proc);
64
65/* Call on-continue handler of BP.  If none is set, call
66 * continue_after_breakpoint.  */
67void breakpoint_on_continue(struct breakpoint *bp, struct Process *proc);
68
69/* Initialize a breakpoint structure.  That doesn't actually realize
70 * the breakpoint.  The breakpoint is initially assumed to be
71 * disabled.  orig_value has to be set separately.  CBS may be
72 * NULL.  */
73int breakpoint_init(struct breakpoint *bp, struct Process *proc,
74		    target_address_t addr, struct library_symbol *libsym);
75
76/* Make a clone of breakpoint BP into the area of memory pointed to by
77 * RETP.  The original breakpoint was assigned to process OLD_PROC,
78 * the cloned breakpoint will be attached to process NEW_PROC.
79 * Returns 0 on success or a negative value on failure.  */
80int breakpoint_clone(struct breakpoint *retp, struct Process *new_proc,
81		     struct breakpoint *bp, struct Process *old_proc);
82
83/* Set callbacks.  If CBS is non-NULL, then BP->cbs shall be NULL.  */
84void breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs);
85
86/* Destroy a breakpoint structure.   */
87void breakpoint_destroy(struct breakpoint *bp);
88
89/* Call enable_breakpoint the first time it's called.  Returns 0 on
90 * success and a negative value on failure.  */
91int breakpoint_turn_on(struct breakpoint *bp, struct Process *proc);
92
93/* Call disable_breakpoint when turned off the same number of times
94 * that it was turned on.  Returns 0 on success and a negative value
95 * on failure.  */
96int breakpoint_turn_off(struct breakpoint *bp, struct Process *proc);
97
98/* Utility function that does what typically needs to be done when a
99 * breakpoint is to be inserted.  It checks whether there is another
100 * breakpoint in PROC for given ADDR.  If not, it allocates memory for
101 * a new breakpoint on the heap, initializes it, and calls
102 * PROC_ADD_BREAKPOINT to add the newly-created breakpoint.  For newly
103 * added as well as preexisting breakpoints, it then calls
104 * BREAKPOINT_TURN_ON.  If anything fails, it cleans up and returns
105 * NULL.  Otherwise it returns the breakpoint for ADDR.  */
106struct breakpoint *insert_breakpoint(struct Process *proc, void *addr,
107				     struct library_symbol *libsym);
108
109/* Name of a symbol associated with BP.  May be NULL.  */
110const char *breakpoint_name(const struct breakpoint *bp);
111
112/* A library that this breakpoint comes from.  May be NULL.  */
113struct library *breakpoint_library(const struct breakpoint *bp);
114
115/* Again, this seems to be several interfaces rolled into one:
116 *  - breakpoint_disable
117 *  - proc_remove_breakpoint
118 *  - breakpoint_destroy
119 * XXX */
120void delete_breakpoint(struct Process *proc, void *addr);
121
122/* XXX some of the following belongs to proc.h/proc.c.  */
123struct breakpoint *address2bpstruct(struct Process *proc, void *addr);
124void enable_all_breakpoints(struct Process *proc);
125void disable_all_breakpoints(struct Process *proc);
126int breakpoints_init(struct Process *proc);
127
128#endif /* BREAKPOINT_H */
129