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/* system/debuggerd/debuggerd.c
**
** Copyright 2012, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include <stddef.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <corkscrew/ptrace.h>
#include <linux/user.h>
#include "../utility.h"
#include "../machine.h"
/* enable to dump memory pointed to by every register */
#define DUMP_MEMORY_FOR_ALL_REGISTERS 1
#define R(x) ((unsigned int)(x))
static void dump_memory(log_t* log, pid_t tid, uintptr_t addr, bool at_fault) {
char code_buffer[64]; /* actual 8+1+((8+1)*4) + 1 == 45 */
char ascii_buffer[32]; /* actual 16 + 1 == 17 */
uintptr_t p, end;
p = addr & ~3;
p -= 32;
if (p > addr) {
/* catch underflow */
p = 0;
}
end = p + 80;
/* catch overflow; 'end - p' has to be multiples of 16 */
while (end < p)
end -= 16;
/* Dump the code around PC as:
* addr contents ascii
* 00008d34 ef000000 e8bd0090 e1b00000 512fff1e ............../Q
* 00008d44 ea00b1f9 e92d0090 e3a070fc ef000000 ......-..p......
*/
while (p < end) {
char* asc_out = ascii_buffer;
sprintf(code_buffer, "%08x ", p);
int i;
for (i = 0; i < 4; i++) {
/*
* If we see (data == -1 && errno != 0), we know that the ptrace
* call failed, probably because we're dumping memory in an
* unmapped or inaccessible page. I don't know if there's
* value in making that explicit in the output -- it likely
* just complicates parsing and clarifies nothing for the
* enlightened reader.
*/
long data = ptrace(PTRACE_PEEKTEXT, tid, (void*)p, NULL);
sprintf(code_buffer + strlen(code_buffer), "%08lx ", data);
int j;
for (j = 0; j < 4; j++) {
/*
* Our isprint() allows high-ASCII characters that display
* differently (often badly) in different viewers, so we
* just use a simpler test.
*/
char val = (data >> (j*8)) & 0xff;
if (val >= 0x20 && val < 0x7f) {
*asc_out++ = val;
} else {
*asc_out++ = '.';
}
}
p += 4;
}
*asc_out = '\0';
_LOG(log, !at_fault, " %s %s\n", code_buffer, ascii_buffer);
}
}
/*
* If configured to do so, dump memory around *all* registers
* for the crashing thread.
*/
void dump_memory_and_code(const ptrace_context_t* context __attribute((unused)),
log_t* log, pid_t tid, bool at_fault) {
pt_regs_mips_t r;
if(ptrace(PTRACE_GETREGS, tid, 0, &r)) {
return;
}
if (at_fault && DUMP_MEMORY_FOR_ALL_REGISTERS) {
static const char REG_NAMES[] = "$0atv0v1a0a1a2a3t0t1t2t3t4t5t6t7s0s1s2s3s4s5s6s7t8t9k0k1gpsps8ra";
for (int reg = 0; reg < 32; reg++) {
/* skip uninteresting registers */
if (reg == 0 /* $0 */
|| reg == 26 /* $k0 */
|| reg == 27 /* $k1 */
|| reg == 31 /* $ra (done below) */
)
continue;
uintptr_t addr = R(r.regs[reg]);
/*
* Don't bother if it looks like a small int or ~= null, or if
* it's in the kernel area.
*/
if (addr < 4096 || addr >= 0x80000000) {
continue;
}
_LOG(log, false, "\nmemory near %.2s:\n", ®_NAMES[reg * 2]);
dump_memory(log, tid, addr, at_fault);
}
}
unsigned int pc = R(r.cp0_epc);
unsigned int ra = R(r.regs[31]);
_LOG(log, !at_fault, "\ncode around pc:\n");
dump_memory(log, tid, (uintptr_t)pc, at_fault);
if (pc != ra) {
_LOG(log, !at_fault, "\ncode around ra:\n");
dump_memory(log, tid, (uintptr_t)ra, at_fault);
}
}
void dump_registers(const ptrace_context_t* context __attribute((unused)),
log_t* log, pid_t tid, bool at_fault)
{
pt_regs_mips_t r;
bool only_in_tombstone = !at_fault;
if(ptrace(PTRACE_GETREGS, tid, 0, &r)) {
_LOG(log, only_in_tombstone, "cannot get registers: %s\n", strerror(errno));
return;
}
_LOG(log, only_in_tombstone, " zr %08x at %08x v0 %08x v1 %08x\n",
R(r.regs[0]), R(r.regs[1]), R(r.regs[2]), R(r.regs[3]));
_LOG(log, only_in_tombstone, " a0 %08x a1 %08x a2 %08x a3 %08x\n",
R(r.regs[4]), R(r.regs[5]), R(r.regs[6]), R(r.regs[7]));
_LOG(log, only_in_tombstone, " t0 %08x t1 %08x t2 %08x t3 %08x\n",
R(r.regs[8]), R(r.regs[9]), R(r.regs[10]), R(r.regs[11]));
_LOG(log, only_in_tombstone, " t4 %08x t5 %08x t6 %08x t7 %08x\n",
R(r.regs[12]), R(r.regs[13]), R(r.regs[14]), R(r.regs[15]));
_LOG(log, only_in_tombstone, " s0 %08x s1 %08x s2 %08x s3 %08x\n",
R(r.regs[16]), R(r.regs[17]), R(r.regs[18]), R(r.regs[19]));
_LOG(log, only_in_tombstone, " s4 %08x s5 %08x s6 %08x s7 %08x\n",
R(r.regs[20]), R(r.regs[21]), R(r.regs[22]), R(r.regs[23]));
_LOG(log, only_in_tombstone, " t8 %08x t9 %08x k0 %08x k1 %08x\n",
R(r.regs[24]), R(r.regs[25]), R(r.regs[26]), R(r.regs[27]));
_LOG(log, only_in_tombstone, " gp %08x sp %08x s8 %08x ra %08x\n",
R(r.regs[28]), R(r.regs[29]), R(r.regs[30]), R(r.regs[31]));
_LOG(log, only_in_tombstone, " hi %08x lo %08x bva %08x epc %08x\n",
R(r.hi), R(r.lo), R(r.cp0_badvaddr), R(r.cp0_epc));
}
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