2 * Copyright (c) 2010 The FreeBSD Foundation
5 * This software was developed by Rui Paulo under sponsorship from the
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/types.h>
34 #include <sys/ptrace.h>
36 #include <machine/_inttypes.h>
44 #if defined(__i386__) || defined(__amd64__)
45 #define BREAKPOINT_INSTR 0xcc /* int 0x3 */
46 #define BREAKPOINT_INSTR_SZ 1
47 #elif defined(__mips__)
48 #define BREAKPOINT_INSTR 0xd /* break */
49 #define BREAKPOINT_INSTR_SZ 4
51 #error "Add support for your architecture"
55 proc_bkptset(struct proc_handle *phdl, uintptr_t address,
58 struct ptrace_io_desc piod;
59 unsigned long paddr, caddr;
62 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
63 phdl->status == PS_IDLE) {
69 * Read the original instruction.
73 piod.piod_op = PIOD_READ_I;
74 piod.piod_offs = (void *)caddr;
75 piod.piod_addr = &paddr;
76 piod.piod_len = BREAKPOINT_INSTR_SZ;
77 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
78 DPRINTF("ERROR: couldn't read instruction at address 0x%" PRIuPTR,
84 * Write a breakpoint instruction to that address.
87 paddr = BREAKPOINT_INSTR;
88 piod.piod_op = PIOD_WRITE_I;
89 piod.piod_offs = (void *)caddr;
90 piod.piod_addr = &paddr;
91 piod.piod_len = BREAKPOINT_INSTR_SZ;
92 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
93 warn("ERROR: couldn't write instruction at address 0x%" PRIuPTR,
102 proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
105 struct ptrace_io_desc piod;
106 unsigned long paddr, caddr;
108 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
109 phdl->status == PS_IDLE) {
113 DPRINTF("removing breakpoint at 0x%lx\n", address);
115 * Overwrite the breakpoint instruction that we setup previously.
119 piod.piod_op = PIOD_WRITE_I;
120 piod.piod_offs = (void *)caddr;
121 piod.piod_addr = &paddr;
122 piod.piod_len = BREAKPOINT_INSTR_SZ;
123 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
124 DPRINTF("ERROR: couldn't write instruction at address 0x%" PRIuPTR,
133 * Decrement pc so that we delete the breakpoint at the correct
134 * address, i.e. at the BREAKPOINT_INSTR address.
137 proc_bkptregadj(unsigned long *pc)
139 *pc = *pc - BREAKPOINT_INSTR_SZ;
143 * Step over the breakpoint.
146 proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
149 unsigned long samesaved;
152 if (proc_regget(phdl, REG_PC, &pc) < 0) {
153 warn("ERROR: couldn't get PC register");
156 proc_bkptregadj(&pc);
157 if (proc_bkptdel(phdl, pc, saved) < 0) {
158 warn("ERROR: couldn't delete breakpoint");
162 * Go back in time and step over the new instruction just
163 * set up by proc_bkptdel().
165 proc_regset(phdl, REG_PC, pc);
166 if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
167 warn("ERROR: ptrace step failed");
171 status = proc_getwstat(phdl);
172 if (!WIFSTOPPED(status)) {
173 warn("ERROR: don't know why process stopped");
177 * Restore the breakpoint. The saved instruction should be
178 * the same as the one that we were passed in.
180 if (proc_bkptset(phdl, pc, &samesaved) < 0) {
181 warn("ERROR: couldn't restore breakpoint");
184 assert(samesaved == saved);