1 /* 2 * This file is part of ltrace. 3 * Copyright (C) 2012,2013,2014 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 46 struct 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_install)(struct breakpoint *bp, struct process *proc); 50 void (*on_retract)(struct breakpoint *bp, struct process *proc); 51 52 /* Create a new breakpoint that should handle return from the 53 * function. BP is the breakpoint that was just hit and for 54 * which we wish to find the corresponding return breakpoint. 55 * This returns 0 on success (in which case *RET will have 56 * been initialized to desired breakpoint object, or NULL if 57 * none is necessary) or a negative value on failure. */ 58 int (*get_return_bp)(struct breakpoint **ret, 59 struct breakpoint *bp, struct process *proc); 60 }; 61 62 struct breakpoint { 63 struct bp_callbacks *cbs; 64 struct library_symbol *libsym; 65 void *addr; 66 unsigned char orig_value[BREAKPOINT_LENGTH]; 67 int enabled; 68 struct arch_breakpoint_data arch; 69 struct os_breakpoint_data os; 70 }; 71 72 /* Call ON_HIT handler of BP, if any is set. */ 73 void breakpoint_on_hit(struct breakpoint *bp, struct process *proc); 74 75 /* Call ON_CONTINUE handler of BP. If none is set, call 76 * continue_after_breakpoint. */ 77 void breakpoint_on_continue(struct breakpoint *bp, struct process *proc); 78 79 /* Call ON_RETRACT handler of BP, if any is set. This should be 80 * called before the breakpoints are destroyed. The reason for a 81 * separate interface is that breakpoint_destroy has to be callable 82 * without PROC. ON_DISABLE might be useful as well, but that would 83 * be called every time we disable the breakpoint, which is too often 84 * (a breakpoint has to be disabled every time that we need to execute 85 * the instruction underneath it). */ 86 void breakpoint_on_retract(struct breakpoint *bp, struct process *proc); 87 88 /* Call ON_INSTALL handler of BP, if any is set. This should be 89 * called after the breakpoint is enabled for the first time, not 90 * every time it's enabled (such as after stepping over a site of a 91 * temporarily disabled breakpoint). */ 92 void breakpoint_on_install(struct breakpoint *bp, struct process *proc); 93 94 /* Call GET_RETURN_BP handler of BP, if any is set. If none is set, 95 * call CREATE_DEFAULT_RETURN_BP to obtain one. */ 96 int breakpoint_get_return_bp(struct breakpoint **ret, 97 struct breakpoint *bp, struct process *proc); 98 99 /* Initialize a breakpoint structure. That doesn't actually realize 100 * the breakpoint. The breakpoint is initially assumed to be 101 * disabled. orig_value has to be set separately. CBS may be 102 * NULL. */ 103 int breakpoint_init(struct breakpoint *bp, struct process *proc, 104 arch_addr_t addr, struct library_symbol *libsym); 105 106 /* Make a clone of breakpoint BP into the area of memory pointed to by 107 * RETP. Symbols of cloned breakpoint are looked up in NEW_PROC. 108 * Returns 0 on success or a negative value on failure. */ 109 int breakpoint_clone(struct breakpoint *retp, struct process *new_proc, 110 struct breakpoint *bp); 111 112 /* Set callbacks. If CBS is non-NULL, then BP->cbs shall be NULL. */ 113 void breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs); 114 115 /* Destroy a breakpoint structure. */ 116 void breakpoint_destroy(struct breakpoint *bp); 117 118 /* Call enable_breakpoint the first time it's called. Returns 0 on 119 * success and a negative value on failure. */ 120 int breakpoint_turn_on(struct breakpoint *bp, struct process *proc); 121 122 /* Call disable_breakpoint when turned off the same number of times 123 * that it was turned on. Returns 0 on success and a negative value 124 * on failure. */ 125 int breakpoint_turn_off(struct breakpoint *bp, struct process *proc); 126 127 /* Allocate and initialize a default return breakpoint. Returns NULL 128 * on failure. */ 129 struct breakpoint *create_default_return_bp(struct process *proc); 130 131 /* This allocates and initializes new breakpoint at ADDR, then calls 132 * INSERT_BREAKPOINT. Returns the new breakpoint or NULL if there are 133 * errors. */ 134 struct breakpoint *insert_breakpoint_at(struct process *proc, arch_addr_t addr, 135 struct library_symbol *libsym); 136 137 /* Check if there is a breakpoint on this address already. If yes, 138 * return that breakpoint instead (BP was not added). If no, try to 139 * PROC_ADD_BREAKPOINT and BREAKPOINT_TURN_ON. If it all works, 140 * return BP. Otherwise return NULL. */ 141 struct breakpoint *insert_breakpoint(struct process *proc, 142 struct breakpoint *bp); 143 144 /* Name of a symbol associated with BP. May be NULL. */ 145 const char *breakpoint_name(const struct breakpoint *bp); 146 147 /* A library that this breakpoint comes from. May be NULL. */ 148 struct library *breakpoint_library(const struct breakpoint *bp); 149 150 /* Again, this seems to be several interfaces rolled into one: 151 * - breakpoint_disable 152 * - proc_remove_breakpoint 153 * - breakpoint_destroy 154 * XXX */ 155 void delete_breakpoint_at(struct process *proc, void *addr); 156 int delete_breakpoint(struct process *proc, struct breakpoint *bp); 157 158 /* XXX some of the following belongs to proc.h/proc.c. */ 159 struct breakpoint *address2bpstruct(struct process *proc, void *addr); 160 void disable_all_breakpoints(struct process *proc); 161 int breakpoints_init(struct process *proc); 162 163 #endif /* BREAKPOINT_H */ 164