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, 91 deletions

diff --git a/debuggerd/libdebuggerd/arm/machine.cpp b/debuggerd/libdebuggerd/arm/machine.cpp
deleted file mode 100644
index bfb5ea4e9..000000000
--- a/debuggerd/libdebuggerd/arm/machine.cpp
+++ /dev/null
@@ -1,91 +0,0 @@
-/*
- *
- * Copyright 2006, 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 <stdint.h>
-#include <string.h>
-#include <sys/ptrace.h>
-
-#include <backtrace/Backtrace.h>
-#include <log/log.h>
-
-#include "libdebuggerd/utility.h"
-
-void dump_memory_and_code(log_t* log, Backtrace* backtrace) {
-  pt_regs regs;
-  if (ptrace(PTRACE_GETREGS, backtrace->Tid(), 0, &regs)) {
-    ALOGE("cannot get registers: %s\n", strerror(errno));
-    return;
-  }
-
-  static const char reg_names[] = "r0r1r2r3r4r5r6r7r8r9slfpipsp";
-
-  for (int reg = 0; reg < 14; reg++) {
-    dump_memory(log, backtrace, regs.uregs[reg], "memory near %.2s:", &reg_names[reg * 2]);
-  }
-
-  dump_memory(log, backtrace, static_cast<uintptr_t>(regs.ARM_pc), "code around pc:");
-
-  if (regs.ARM_pc != regs.ARM_lr) {
-    dump_memory(log, backtrace, static_cast<uintptr_t>(regs.ARM_lr), "code around lr:");
-  }
-}
-
-#define DUMP_GP_REGISTERS(log, reg_prefix)                                             \
-  _LOG(log, logtype::REGISTERS, "    r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",            \
-       static_cast<uint32_t>(reg_prefix##r0), static_cast<uint32_t>(reg_prefix##r1),   \
-       static_cast<uint32_t>(reg_prefix##r2), static_cast<uint32_t>(reg_prefix##r3));  \
-  _LOG(log, logtype::REGISTERS, "    r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",            \
-       static_cast<uint32_t>(reg_prefix##r4), static_cast<uint32_t>(reg_prefix##r5),   \
-       static_cast<uint32_t>(reg_prefix##r6), static_cast<uint32_t>(reg_prefix##r7));  \
-  _LOG(log, logtype::REGISTERS, "    r8 %08x  r9 %08x  sl %08x  fp %08x\n",            \
-       static_cast<uint32_t>(reg_prefix##r8), static_cast<uint32_t>(reg_prefix##r9),   \
-       static_cast<uint32_t>(reg_prefix##r10), static_cast<uint32_t>(reg_prefix##fp)); \
-  _LOG(log, logtype::REGISTERS, "    ip %08x  sp %08x  lr %08x  pc %08x  cpsr %08x\n", \
-       static_cast<uint32_t>(reg_prefix##ip), static_cast<uint32_t>(reg_prefix##sp),   \
-       static_cast<uint32_t>(reg_prefix##lr), static_cast<uint32_t>(reg_prefix##pc),   \
-       static_cast<uint32_t>(reg_prefix##cpsr))
-
-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;
-  }
-
-  DUMP_GP_REGISTERS(log, r.ARM_);
-
-  user_vfp vfp_regs;
-  if (ptrace(PTRACE_GETVFPREGS, tid, 0, &vfp_regs)) {
-    ALOGE("cannot get FP registers: %s\n", strerror(errno));
-    return;
-  }
-
-  for (size_t i = 0; i < 32; i += 2) {
-    _LOG(log, logtype::FP_REGISTERS, "    d%-2d %016llx  d%-2d %016llx\n",
-         i, vfp_regs.fpregs[i], i+1, vfp_regs.fpregs[i+1]);
-  }
-  _LOG(log, logtype::FP_REGISTERS, "    scr %08lx\n", vfp_regs.fpscr);
-}
-
-void dump_registers(log_t* log, const ucontext_t* uc) {
-  DUMP_GP_REGISTERS(log, uc->uc_mcontext.arm_);
-}