breakpoint.h revision 29add4fdf852b10ddd22cac0d1390f6d01577bc2
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 * Tracepoints are provided by the main binary as well as by any 37 * opened libraries: every time an ELF file is mapped into the address 38 * space, a new set of tracepoints is extracted, and filtered 39 * according to user settings. Those tracepoints that are left are 40 * then realized, and the tracing starts. 41 * 42 * A scheme like this would take care of gradually introducing 43 * breakpoints when the library is mapped, and therefore ready, and 44 * would avoid certain hacks. For example on PPC64, we don't actually 45 * add breakpoints to PLT. Instead, we read the PLT (which contains 46 * addresses, not code), to figure out where to put the breakpoints. 47 * In prelinked code, that address is non-zero, and points to an 48 * address that's not yet mapped. ptrace then fails when we try to 49 * add the breakpoint. 50 * 51 * Ideally, return breakpoints would be just a special kind of 52 * tracepoint that has attached some magic. Or a feature of a 53 * tracepoint. Service breakpoints like the handling of dlopen would 54 * be a low-level breakpoint, likely without tracepoint attached. 55 * 56 * So that's for sometimes. 57 */ 58 59#include "arch.h" 60#include "library.h" 61 62struct Process; 63struct breakpoint; 64 65struct bp_callbacks { 66 void (*on_hit) (struct breakpoint *bp, struct Process *proc); 67 void (*on_destroy) (struct breakpoint *bp); 68}; 69 70#ifndef ARCH_HAVE_BREAKPOINT_DATA 71struct arch_breakpoint_data { 72}; 73#endif 74 75struct breakpoint { 76 struct bp_callbacks *cbs; 77 struct library_symbol *libsym; 78 void *addr; 79 unsigned char orig_value[BREAKPOINT_LENGTH]; 80 int enabled; 81 struct arch_breakpoint_data arch; 82}; 83 84/* Call on-hit handler of BP, if any is set. */ 85void breakpoint_on_hit(struct breakpoint *bp, struct Process *proc); 86 87/* Call on-destroy handler of BP, if any is set. */ 88void breakpoint_on_destroy(struct breakpoint *bp); 89 90/* Initialize a breakpoint structure. That doesn't actually realize 91 * the breakpoint. The breakpoint is initially assumed to be 92 * disabled. orig_value has to be set separately. CBS may be 93 * NULL. */ 94int breakpoint_init(struct breakpoint *bp, struct Process *proc, 95 target_address_t addr, struct library_symbol *libsym, 96 struct bp_callbacks *cbs); 97 98/* This is actually three functions rolled in one: 99 * - breakpoint_init 100 * - proc_insert_breakpoint 101 * - breakpoint_enable 102 * XXX I think it should be broken up somehow. */ 103struct breakpoint *insert_breakpoint(struct Process *proc, void *addr, 104 struct library_symbol *libsym, int enable); 105 106/* */ 107void delete_breakpoint(struct Process *proc, void *addr); 108 109/* XXX some of the following belongs to proc.h/proc.c. */ 110struct breakpoint *address2bpstruct(struct Process *proc, void *addr); 111void enable_all_breakpoints(struct Process *proc); 112void disable_all_breakpoints(struct Process *proc); 113int breakpoints_init(struct Process *proc, int enable); 114 115#endif /* BREAKPOINT_H */ 116