breakpoint.h revision 9294d82f67e20f5f2b61f317ad04f5cb717c7d27
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 61struct Process; 62 63typedef struct breakpoint Breakpoint; 64struct breakpoint { 65 void *addr; 66 unsigned char orig_value[BREAKPOINT_LENGTH]; 67 int enabled; 68 struct library_symbol *libsym; 69#ifdef __arm__ 70 int thumb_mode; 71#endif 72}; 73 74/* This is actually three functions rolled in one: 75 * - breakpoint_init 76 * - proc_insert_breakpoint 77 * - breakpoint_enable 78 * XXX I think it should be broken up somehow. */ 79struct breakpoint *insert_breakpoint(struct Process *proc, void *addr, 80 struct library_symbol *libsym, int enable); 81 82/* */ 83void delete_breakpoint(struct Process *proc, void *addr); 84 85/* XXX some of the following belongs to proc.h/proc.c. */ 86struct breakpoint *address2bpstruct(struct Process *proc, void *addr); 87void enable_all_breakpoints(struct Process *proc); 88void disable_all_breakpoints(struct Process *proc); 89int breakpoints_init(struct Process *proc, int enable); 90 91void reinitialize_breakpoints(struct Process *proc); 92 93 94#endif /* BREAKPOINT_H */ 95