crash_dump: fork a copy of the target's address space.

Reduce the amount of time that a process remains paused by pausing its
threads, fetching their registers, and then performing unwinding on a
copy of its address space. This also works around a kernel change
that's in 4.9 that prevents ptrace from reading memory of processes
that we don't have immediate permissions to ptrace (even if we
previously ptraced them).

Bug: http://b/62112103
Bug: http://b/63989615
Test: treehugger
Change-Id: I7b9cc5dd8f54a354bc61f1bda0d2b7a8a55733c4

1 files changed, 0 insertions, 99 deletions

diff --git a/debuggerd/libdebuggerd/mips/machine.cpp b/debuggerd/libdebuggerd/mips/machine.cpp
deleted file mode 100644
index 1fc690b4a..000000000
--- a/debuggerd/libdebuggerd/mips/machine.cpp
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * 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.
- */
-
-#define LOG_TAG "DEBUG"
-
-#include "libdebuggerd/machine.h"
-
-#include <errno.h>
-#include <inttypes.h>
-#include <stdint.h>
-#include <string.h>
-#include <sys/ptrace.h>
-
-#include <backtrace/Backtrace.h>
-#include <log/log.h>
-
-#include "libdebuggerd/utility.h"
-
-#define R(x) (static_cast<uintptr_t>(x))
-
-// If configured to do so, dump memory around *all* registers
-// for the crashing thread.
-void dump_memory_and_code(log_t* log, Backtrace* backtrace) {
-  pt_regs r;
-  if (ptrace(PTRACE_GETREGS, backtrace->Tid(), 0, &r)) {
-    ALOGE("cannot get registers: %s\n", strerror(errno));
-    return;
-  }
-
-  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;
-
-    dump_memory(log, backtrace, R(r.regs[reg]), "memory near %.2s:", &reg_names[reg * 2]);
-  }
-
-  uintptr_t pc = R(r.cp0_epc);
-  uintptr_t ra = R(r.regs[31]);
-  dump_memory(log, backtrace, pc, "code around pc:");
-  if (pc != ra) {
-    dump_memory(log, backtrace, ra, "code around ra:");
-  }
-}
-
-void dump_registers(log_t* log, pid_t tid) {
-  pt_regs r;
-  if(ptrace(PTRACE_GETREGS, tid, 0, &r)) {
-    ALOGE("cannot get registers: %s\n", strerror(errno));
-    return;
-  }
-
-  _LOG(log, logtype::REGISTERS, " zr %08" PRIxPTR "  at %08" PRIxPTR
-       "  v0 %08" PRIxPTR "  v1 %08" PRIxPTR "\n",
-       R(r.regs[0]), R(r.regs[1]), R(r.regs[2]), R(r.regs[3]));
-  _LOG(log, logtype::REGISTERS, " a0 %08" PRIxPTR "  a1 %08" PRIxPTR
-       "  a2 %08" PRIxPTR "  a3 %08" PRIxPTR "\n",
-       R(r.regs[4]), R(r.regs[5]), R(r.regs[6]), R(r.regs[7]));
-  _LOG(log, logtype::REGISTERS, " t0 %08" PRIxPTR "  t1 %08" PRIxPTR
-       "  t2 %08" PRIxPTR "  t3 %08" PRIxPTR "\n",
-       R(r.regs[8]), R(r.regs[9]), R(r.regs[10]), R(r.regs[11]));
-  _LOG(log, logtype::REGISTERS, " t4 %08" PRIxPTR "  t5 %08" PRIxPTR
-       "  t6 %08" PRIxPTR "  t7 %08" PRIxPTR "\n",
-       R(r.regs[12]), R(r.regs[13]), R(r.regs[14]), R(r.regs[15]));
-  _LOG(log, logtype::REGISTERS, " s0 %08" PRIxPTR "  s1 %08" PRIxPTR
-       "  s2 %08" PRIxPTR "  s3 %08" PRIxPTR "\n",
-       R(r.regs[16]), R(r.regs[17]), R(r.regs[18]), R(r.regs[19]));
-  _LOG(log, logtype::REGISTERS, " s4 %08" PRIxPTR "  s5 %08" PRIxPTR
-       "  s6 %08" PRIxPTR "  s7 %08" PRIxPTR "\n",
-       R(r.regs[20]), R(r.regs[21]), R(r.regs[22]), R(r.regs[23]));
-  _LOG(log, logtype::REGISTERS, " t8 %08" PRIxPTR "  t9 %08" PRIxPTR
-       "  k0 %08" PRIxPTR "  k1 %08" PRIxPTR "\n",
-       R(r.regs[24]), R(r.regs[25]), R(r.regs[26]), R(r.regs[27]));
-  _LOG(log, logtype::REGISTERS, " gp %08" PRIxPTR "  sp %08" PRIxPTR
-       "  s8 %08" PRIxPTR "  ra %08" PRIxPTR "\n",
-       R(r.regs[28]), R(r.regs[29]), R(r.regs[30]), R(r.regs[31]));
-  _LOG(log, logtype::REGISTERS, " hi %08" PRIxPTR "  lo %08" PRIxPTR
-       " bva %08" PRIxPTR " epc %08" PRIxPTR "\n",
-       R(r.hi), R(r.lo), R(r.cp0_badvaddr), R(r.cp0_epc));
-}