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>
45 #if defined(__i386__) || defined(__amd64__)
46 #define BREAKPOINT_INSTR 0xcc /* int 0x3 */
47 #define BREAKPOINT_INSTR_SZ 1
49 #error "Add support for your architecture"
53 proc_cont(struct proc_handle *phdl)
56 ptrace(PT_CONTINUE, proc_getpid(phdl), (caddr_t)1, 0);
60 proc_stop(struct proc_handle *phdl)
64 if (kill(proc_getpid(phdl), SIGSTOP) == -1) {
65 DPRINTF("kill %d", proc_getpid(phdl));
67 } else if (waitpid(proc_getpid(phdl), &status, WSTOPPED) == -1) {
68 DPRINTF("waitpid %d", proc_getpid(phdl));
70 } else if (!WIFSTOPPED(status)) {
71 DPRINTFX("waitpid: unexpected status 0x%x", status);
79 proc_bkptset(struct proc_handle *phdl, uintptr_t address,
82 struct ptrace_io_desc piod;
83 unsigned long paddr, caddr;
87 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
88 phdl->status == PS_IDLE) {
93 DPRINTFX("adding breakpoint at 0x%lx", address);
95 if (phdl->status != PS_STOP)
96 if (proc_stop(phdl) != 0)
100 * Read the original instruction.
104 piod.piod_op = PIOD_READ_I;
105 piod.piod_offs = (void *)caddr;
106 piod.piod_addr = &paddr;
107 piod.piod_len = BREAKPOINT_INSTR_SZ;
108 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
109 DPRINTF("ERROR: couldn't read instruction at address 0x%"
116 * Write a breakpoint instruction to that address.
119 paddr = BREAKPOINT_INSTR;
120 piod.piod_op = PIOD_WRITE_I;
121 piod.piod_offs = (void *)caddr;
122 piod.piod_addr = &paddr;
123 piod.piod_len = BREAKPOINT_INSTR_SZ;
124 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
125 DPRINTF("ERROR: couldn't write instruction at address 0x%"
132 if (phdl->status != PS_STOP)
133 /* Restart the process if we had to stop it. */
140 proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
143 struct ptrace_io_desc piod;
144 unsigned long paddr, caddr;
147 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
148 phdl->status == PS_IDLE) {
153 DPRINTFX("removing breakpoint at 0x%lx", address);
155 if (phdl->status != PS_STOP)
156 if (proc_stop(phdl) != 0)
160 * Overwrite the breakpoint instruction that we setup previously.
164 piod.piod_op = PIOD_WRITE_I;
165 piod.piod_offs = (void *)caddr;
166 piod.piod_addr = &paddr;
167 piod.piod_len = BREAKPOINT_INSTR_SZ;
168 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
169 DPRINTF("ERROR: couldn't write instruction at address 0x%"
174 if (phdl->status != PS_STOP)
175 /* Restart the process if we had to stop it. */
182 * Decrement pc so that we delete the breakpoint at the correct
183 * address, i.e. at the BREAKPOINT_INSTR address.
186 proc_bkptregadj(unsigned long *pc)
188 *pc = *pc - BREAKPOINT_INSTR_SZ;
192 * Step over the breakpoint.
195 proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
198 unsigned long samesaved;
201 if (proc_regget(phdl, REG_PC, &pc) < 0) {
202 DPRINTFX("ERROR: couldn't get PC register");
205 proc_bkptregadj(&pc);
206 if (proc_bkptdel(phdl, pc, saved) < 0) {
207 DPRINTFX("ERROR: couldn't delete breakpoint");
211 * Go back in time and step over the new instruction just
212 * set up by proc_bkptdel().
214 proc_regset(phdl, REG_PC, pc);
215 if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
216 DPRINTFX("ERROR: ptrace step failed");
220 status = proc_getwstat(phdl);
221 if (!WIFSTOPPED(status)) {
222 DPRINTFX("ERROR: don't know why process stopped");
226 * Restore the breakpoint. The saved instruction should be
227 * the same as the one that we were passed in.
229 if (proc_bkptset(phdl, pc, &samesaved) < 0) {
230 DPRINTFX("ERROR: couldn't restore breakpoint");
233 assert(samesaved == saved);