Replace libbacktrace with libunwindstack directly.

Small modifications to the dump_stack method and added unit tests to
verify the output.

Bug: 120606663

Test: Unit tests pass, debuggerd run on processes on target.
Change-Id: Id385a915b751abda3dd6baebed6c3ce498c3bf6e

1 files changed, 115 insertions, 106 deletions

diff --git a/debuggerd/libdebuggerd/tombstone.cpp b/debuggerd/libdebuggerd/tombstone.cpp
index b20014f59..8798ad3d3 100644
--- a/debuggerd/libdebuggerd/tombstone.cpp
+++ b/debuggerd/libdebuggerd/tombstone.cpp
@@ -41,19 +41,20 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <android/log.h>
-#include <backtrace/Backtrace.h>
-#include <backtrace/BacktraceMap.h>
 #include <log/log.h>
 #include <log/logprint.h>
 #include <private/android_filesystem_config.h>
+#include <unwindstack/DexFiles.h>
+#include <unwindstack/JitDebug.h>
+#include <unwindstack/Maps.h>
 #include <unwindstack/Memory.h>
 #include <unwindstack/Regs.h>
+#include <unwindstack/Unwinder.h>
 
 // Needed to get DEBUGGER_SIGNAL.
 #include "debuggerd/handler.h"
 
 #include "libdebuggerd/backtrace.h"
-#include "libdebuggerd/elf_utils.h"
 #include "libdebuggerd/open_files_list.h"
 #include "libdebuggerd/utility.h"
 
@@ -62,9 +63,6 @@ using android::base::GetProperty;
 using android::base::StringPrintf;
 using android::base::unique_fd;
 
-using unwindstack::Memory;
-using unwindstack::Regs;
-
 using namespace std::literals::string_literals;
 
 #define STACK_WORDS 16
@@ -87,7 +85,7 @@ static void dump_timestamp(log_t* log, time_t time) {
   _LOG(log, logtype::HEADER, "Timestamp: %s\n", buf);
 }
 
-static void dump_probable_cause(log_t* log, const siginfo_t* si, BacktraceMap* map) {
+static void dump_probable_cause(log_t* log, const siginfo_t* si, unwindstack::Maps* maps) {
   std::string cause;
   if (si->si_signo == SIGSEGV && si->si_code == SEGV_MAPERR) {
     if (si->si_addr < reinterpret_cast<void*>(4096)) {
@@ -104,12 +102,9 @@ static void dump_probable_cause(log_t* log, const siginfo_t* si, BacktraceMap* m
       cause = "call to kuser_cmpxchg64";
     }
   } else if (si->si_signo == SIGSEGV && si->si_code == SEGV_ACCERR) {
-    for (auto it = map->begin(); it != map->end(); ++it) {
-      const backtrace_map_t* entry = *it;
-      if (si->si_addr >= reinterpret_cast<void*>(entry->start) &&
-          si->si_addr < reinterpret_cast<void*>(entry->end) && entry->flags == PROT_EXEC) {
-        cause = "execute-only (no-read) memory access error; likely due to data in .text.";
-      }
+    unwindstack::MapInfo* map_info = maps->Find(reinterpret_cast<uint64_t>(si->si_addr));
+    if (map_info != nullptr && map_info->flags == PROT_EXEC) {
+      cause = "execute-only (no-read) memory access error; likely due to data in .text.";
     }
   } else if (si->si_signo == SIGSYS && si->si_code == SYS_SECCOMP) {
     cause = StringPrintf("seccomp prevented call to disallowed %s system call %d", ABI_STRING,
@@ -119,7 +114,8 @@ static void dump_probable_cause(log_t* log, const siginfo_t* si, BacktraceMap* m
   if (!cause.empty()) _LOG(log, logtype::HEADER, "Cause: %s\n", cause.c_str());
 }
 
-static void dump_signal_info(log_t* log, const ThreadInfo& thread_info, Memory* process_memory) {
+static void dump_signal_info(log_t* log, const ThreadInfo& thread_info,
+                             unwindstack::Memory* process_memory) {
   char addr_desc[64];  // ", fault addr 0x1234"
   if (signal_has_si_addr(thread_info.siginfo)) {
     void* addr = thread_info.siginfo->si_addr;
@@ -156,14 +152,14 @@ static void dump_thread_info(log_t* log, const ThreadInfo& thread_info) {
        thread_info.tid, thread_info.thread_name.c_str(), thread_info.process_name.c_str());
 }
 
-static void dump_stack_segment(log_t* log, BacktraceMap* backtrace_map, Memory* process_memory,
+static void dump_stack_segment(log_t* log, unwindstack::Maps* maps, unwindstack::Memory* memory,
                                uint64_t* sp, size_t words, int label) {
   // Read the data all at once.
   word_t stack_data[words];
 
   // TODO: Do we need to word align this for crashes caused by a misaligned sp?
   //       The process_vm_readv implementation of Memory should handle this appropriately?
-  size_t bytes_read = process_memory->Read(*sp, stack_data, sizeof(word_t) * words);
+  size_t bytes_read = memory->Read(*sp, stack_data, sizeof(word_t) * words);
   words = bytes_read / sizeof(word_t);
   std::string line;
   for (size_t i = 0; i < words; i++) {
@@ -176,17 +172,15 @@ static void dump_stack_segment(log_t* log, BacktraceMap* backtrace_map, Memory*
     }
     line += StringPrintf("%" PRIPTR "  %" PRIPTR, *sp, static_cast<uint64_t>(stack_data[i]));
 
-    backtrace_map_t map;
-    backtrace_map->FillIn(stack_data[i], &map);
-    std::string map_name{map.Name()};
-    if (BacktraceMap::IsValid(map) && !map_name.empty()) {
-      line += "  " + map_name;
-      uint64_t offset = 0;
-      std::string func_name = backtrace_map->GetFunctionName(stack_data[i], &offset);
-      if (!func_name.empty()) {
+    unwindstack::MapInfo* map_info = maps->Find(stack_data[i]);
+    if (map_info != nullptr && !map_info->name.empty()) {
+      line += "  " + map_info->name;
+      std::string func_name;
+      uint64_t func_offset = 0;
+      if (map_info->GetFunctionName(stack_data[i], &func_name, &func_offset)) {
         line += " (" + func_name;
-        if (offset) {
-          line += StringPrintf("+%" PRIu64, offset);
+        if (func_offset) {
+          line += StringPrintf("+%" PRIu64, func_offset);
         }
         line += ')';
       }
@@ -197,12 +191,11 @@ static void dump_stack_segment(log_t* log, BacktraceMap* backtrace_map, Memory*
   }
 }
 
-static void dump_stack(log_t* log, BacktraceMap* backtrace_map, Memory* process_memory,
-                       std::vector<backtrace_frame_data_t>& frames) {
+static void dump_stack(log_t* log, const std::vector<unwindstack::FrameData>& frames,
+                       unwindstack::Maps* maps, unwindstack::Memory* memory) {
   size_t first = 0, last;
   for (size_t i = 0; i < frames.size(); i++) {
-    const backtrace_frame_data_t& frame = frames[i];
-    if (frame.sp) {
+    if (frames[i].sp) {
       if (!first) {
         first = i+1;
       }
@@ -217,29 +210,44 @@ static void dump_stack(log_t* log, BacktraceMap* backtrace_map, Memory* process_
 
   // Dump a few words before the first frame.
   uint64_t sp = frames[first].sp - STACK_WORDS * sizeof(word_t);
-  dump_stack_segment(log, backtrace_map, process_memory, &sp, STACK_WORDS, -1);
+  dump_stack_segment(log, maps, memory, &sp, STACK_WORDS, -1);
+
+#if defined(__LP64__)
+  static constexpr const char delimiter[] = "         ................  ................\n";
+#else
+  static constexpr const char delimiter[] = "         ........  ........\n";
+#endif
 
   // Dump a few words from all successive frames.
-  // Only log the first 3 frames, put the rest in the tombstone.
   for (size_t i = first; i <= last; i++) {
-    const backtrace_frame_data_t* frame = &frames[i];
+    auto* frame = &frames[i];
     if (sp != frame->sp) {
-      _LOG(log, logtype::STACK, "         ........  ........\n");
+      _LOG(log, logtype::STACK, delimiter);
       sp = frame->sp;
     }
-    if (i == last) {
-      dump_stack_segment(log, backtrace_map, process_memory, &sp, STACK_WORDS, i);
-      if (sp < frame->sp + frame->stack_size) {
-        _LOG(log, logtype::STACK, "         ........  ........\n");
-      }
-    } else {
-      size_t words = frame->stack_size / sizeof(word_t);
-      if (words == 0) {
-        words = 1;
-      } else if (words > STACK_WORDS) {
+    if (i != last) {
+      // Print stack data up to the stack from the next frame.
+      size_t words;
+      uint64_t next_sp = frames[i + 1].sp;
+      if (next_sp < sp) {
+        // The next frame is probably using a completely different stack,
+        // so dump the max from this stack.
         words = STACK_WORDS;
+      } else {
+        words = (next_sp - sp) / sizeof(word_t);
+        if (words == 0) {
+          // The sp is the same as the next frame, print at least
+          // one line for this frame.
+          words = 1;
+        } else if (words > STACK_WORDS) {
+          words = STACK_WORDS;
+        }
       }
-      dump_stack_segment(log, backtrace_map, process_memory, &sp, words, i);
+      dump_stack_segment(log, maps, memory, &sp, words, i);
+    } else {
+      // Print some number of words past the last stack frame since we
+      // don't know how large the stack is.
+      dump_stack_segment(log, maps, memory, &sp, STACK_WORDS, i);
     }
   }
 }
@@ -256,7 +264,7 @@ static std::string get_addr_string(uint64_t addr) {
   return addr_str;
 }
 
-static void dump_abort_message(log_t* log, Memory* process_memory, uint64_t address) {
+static void dump_abort_message(log_t* log, unwindstack::Memory* process_memory, uint64_t address) {
   if (address == 0) {
     return;
   }
@@ -285,16 +293,16 @@ static void dump_abort_message(log_t* log, Memory* process_memory, uint64_t addr
   _LOG(log, logtype::HEADER, "Abort message: '%s'\n", &msg[0]);
 }
 
-static void dump_all_maps(log_t* log, BacktraceMap* map, Memory* process_memory, uint64_t addr) {
+static void dump_all_maps(log_t* log, unwindstack::Unwinder* unwinder, uint64_t addr) {
   bool print_fault_address_marker = addr;
 
-  ScopedBacktraceMapIteratorLock lock(map);
+  unwindstack::Maps* maps = unwinder->GetMaps();
   _LOG(log, logtype::MAPS,
        "\n"
        "memory map (%zu entr%s):",
-       map->size(), map->size() == 1 ? "y" : "ies");
+       maps->Total(), maps->Total() == 1 ? "y" : "ies");
   if (print_fault_address_marker) {
-    if (map->begin() != map->end() && addr < (*map->begin())->start) {
+    if (maps->Total() != 0 && addr < maps->Get(0)->start) {
       _LOG(log, logtype::MAPS, "\n--->Fault address falls at %s before any mapped regions\n",
            get_addr_string(addr).c_str());
       print_fault_address_marker = false;
@@ -305,51 +313,54 @@ static void dump_all_maps(log_t* log, BacktraceMap* map, Memory* process_memory,
     _LOG(log, logtype::MAPS, "\n");
   }
 
+  std::shared_ptr<unwindstack::Memory>& process_memory = unwinder->GetProcessMemory();
+
   std::string line;
-  for (auto it = map->begin(); it != map->end(); ++it) {
-    const backtrace_map_t* entry = *it;
+  for (unwindstack::MapInfo* map_info : *maps) {
     line = "    ";
     if (print_fault_address_marker) {
-      if (addr < entry->start) {
+      if (addr < map_info->start) {
         _LOG(log, logtype::MAPS, "--->Fault address falls at %s between mapped regions\n",
              get_addr_string(addr).c_str());
         print_fault_address_marker = false;
-      } else if (addr >= entry->start && addr < entry->end) {
+      } else if (addr >= map_info->start && addr < map_info->end) {
         line = "--->";
         print_fault_address_marker = false;
       }
     }
-    line += get_addr_string(entry->start) + '-' + get_addr_string(entry->end - 1) + ' ';
-    if (entry->flags & PROT_READ) {
+    line += get_addr_string(map_info->start) + '-' + get_addr_string(map_info->end - 1) + ' ';
+    if (map_info->flags & PROT_READ) {
       line += 'r';
     } else {
       line += '-';
     }
-    if (entry->flags & PROT_WRITE) {
+    if (map_info->flags & PROT_WRITE) {
       line += 'w';
     } else {
       line += '-';
     }
-    if (entry->flags & PROT_EXEC) {
+    if (map_info->flags & PROT_EXEC) {
       line += 'x';
     } else {
       line += '-';
     }
-    line += StringPrintf("  %8" PRIx64 "  %8" PRIx64, entry->offset, entry->end - entry->start);
+    line += StringPrintf("  %8" PRIx64 "  %8" PRIx64, map_info->offset,
+                         map_info->end - map_info->start);
     bool space_needed = true;
-    if (entry->name.length() > 0) {
+    if (!map_info->name.empty()) {
       space_needed = false;
-      line += "  " + entry->name;
-      std::string build_id;
-      if ((entry->flags & PROT_READ) && elf_get_build_id(process_memory, entry->start, &build_id)) {
+      line += "  " + map_info->name;
+      std::string build_id = map_info->GetPrintableBuildID();
+      if (!build_id.empty()) {
         line += " (BuildId: " + build_id + ")";
       }
     }
-    if (entry->load_bias != 0) {
+    uint64_t load_bias = map_info->GetLoadBias(process_memory);
+    if (load_bias != 0) {
       if (space_needed) {
         line += ' ';
       }
-      line += StringPrintf(" (load bias 0x%" PRIx64 ")", entry->load_bias);
+      line += StringPrintf(" (load bias 0x%" PRIx64 ")", load_bias);
     }
     _LOG(log, logtype::MAPS, "%s\n", line.c_str());
   }
@@ -359,9 +370,9 @@ static void dump_all_maps(log_t* log, BacktraceMap* map, Memory* process_memory,
   }
 }
 
-void dump_backtrace(log_t* log, std::vector<backtrace_frame_data_t>& frames, const char* prefix) {
-  for (auto& frame : frames) {
-    _LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, Backtrace::FormatFrameData(&frame).c_str());
+void dump_backtrace(log_t* log, unwindstack::Unwinder* unwinder, const char* prefix) {
+  for (size_t i = 0; i < unwinder->NumFrames(); i++) {
+    _LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, unwinder->FormatFrame(i).c_str());
   }
 }
 
@@ -377,7 +388,7 @@ static void print_register_row(log_t* log,
   _LOG(log, logtype::REGISTERS, "  %s\n", output.c_str());
 }
 
-void dump_registers(log_t* log, Regs* regs) {
+void dump_registers(log_t* log, unwindstack::Regs* regs) {
   // Split lr/sp/pc into their own special row.
   static constexpr size_t column_count = 4;
   std::vector<std::pair<std::string, uint64_t>> current_row;
@@ -416,23 +427,22 @@ void dump_registers(log_t* log, Regs* regs) {
   print_register_row(log, special_row);
 }
 
-void dump_memory_and_code(log_t* log, BacktraceMap* map, Memory* memory, Regs* regs) {
-  regs->IterateRegisters([log, map, memory](const char* reg_name, uint64_t reg_value) {
+void dump_memory_and_code(log_t* log, unwindstack::Maps* maps, unwindstack::Memory* memory,
+                          unwindstack::Regs* regs) {
+  regs->IterateRegisters([log, maps, memory](const char* reg_name, uint64_t reg_value) {
     std::string label{"memory near "s + reg_name};
-    if (map) {
-      backtrace_map_t map_info;
-      map->FillIn(reg_value, &map_info);
-      std::string map_name{map_info.Name()};
-      if (!map_name.empty()) label += " (" + map_info.Name() + ")";
+    if (maps) {
+      unwindstack::MapInfo* map_info = maps->Find(reg_value);
+      if (map_info != nullptr && !map_info->name.empty()) {
+        label += " (" + map_info->name + ")";
+      }
     }
     dump_memory(log, memory, reg_value, label);
   });
 }
 
-static bool dump_thread(log_t* log, BacktraceMap* map, Memory* process_memory,
-                        const ThreadInfo& thread_info, uint64_t abort_msg_address,
-                        bool primary_thread) {
-  UNUSED(process_memory);
+static bool dump_thread(log_t* log, unwindstack::Unwinder* unwinder, const ThreadInfo& thread_info,
+                        uint64_t abort_msg_address, bool primary_thread) {
   log->current_tid = thread_info.tid;
   if (!primary_thread) {
     _LOG(log, logtype::THREAD, "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
@@ -440,41 +450,41 @@ static bool dump_thread(log_t* log, BacktraceMap* map, Memory* process_memory,
   dump_thread_info(log, thread_info);
 
   if (thread_info.siginfo) {
-    dump_signal_info(log, thread_info, process_memory);
-    dump_probable_cause(log, thread_info.siginfo, map);
+    dump_signal_info(log, thread_info, unwinder->GetProcessMemory().get());
+    dump_probable_cause(log, thread_info.siginfo, unwinder->GetMaps());
   }
 
   if (primary_thread) {
-    dump_abort_message(log, process_memory, abort_msg_address);
+    dump_abort_message(log, unwinder->GetProcessMemory().get(), abort_msg_address);
   }
 
   dump_registers(log, thread_info.registers.get());
 
   // Unwind will mutate the registers, so make a copy first.
-  std::unique_ptr<Regs> regs_copy(thread_info.registers->Clone());
-  std::vector<backtrace_frame_data_t> frames;
-  if (!Backtrace::Unwind(regs_copy.get(), map, &frames, 0, nullptr)) {
+  std::unique_ptr<unwindstack::Regs> regs_copy(thread_info.registers->Clone());
+  unwinder->SetRegs(regs_copy.get());
+  unwinder->Unwind();
+  if (unwinder->NumFrames() == 0) {
     _LOG(log, logtype::THREAD, "Failed to unwind");
-    return false;
-  }
-
-  if (!frames.empty()) {
+  } else {
     _LOG(log, logtype::BACKTRACE, "\nbacktrace:\n");
-    dump_backtrace(log, frames, "    ");
+    dump_backtrace(log, unwinder, "    ");
 
     _LOG(log, logtype::STACK, "\nstack:\n");
-    dump_stack(log, map, process_memory, frames);
+    dump_stack(log, unwinder->frames(), unwinder->GetMaps(), unwinder->GetProcessMemory().get());
   }
 
   if (primary_thread) {
-    dump_memory_and_code(log, map, process_memory, thread_info.registers.get());
-    if (map) {
+    unwindstack::Maps* maps = unwinder->GetMaps();
+    dump_memory_and_code(log, maps, unwinder->GetProcessMemory().get(),
+                         thread_info.registers.get());
+    if (maps != nullptr) {
       uint64_t addr = 0;
       siginfo_t* si = thread_info.siginfo;
       if (signal_has_si_addr(si)) {
         addr = reinterpret_cast<uint64_t>(si->si_addr);
       }
-      dump_all_maps(log, map, process_memory, addr);
+      dump_all_maps(log, unwinder, addr);
     }
   }
 
@@ -625,7 +635,8 @@ void engrave_tombstone_ucontext(int tombstone_fd, uint64_t abort_msg_address, si
   read_with_default("/proc/self/comm", thread_name, sizeof(thread_name), "<unknown>");
   read_with_default("/proc/self/cmdline", process_name, sizeof(process_name), "<unknown>");
 
-  std::unique_ptr<Regs> regs(Regs::CreateFromUcontext(Regs::CurrentArch(), ucontext));
+  std::unique_ptr<unwindstack::Regs> regs(
+      unwindstack::Regs::CreateFromUcontext(unwindstack::Regs::CurrentArch(), ucontext));
 
   std::map<pid_t, ThreadInfo> threads;
   threads[gettid()] = ThreadInfo{
@@ -637,18 +648,16 @@ void engrave_tombstone_ucontext(int tombstone_fd, uint64_t abort_msg_address, si
       .siginfo = siginfo,
   };
 
-  std::unique_ptr<BacktraceMap> backtrace_map(BacktraceMap::Create(getpid(), false));
-  if (!backtrace_map) {
-    ALOGE("failed to create backtrace map");
-    _exit(1);
+  unwindstack::UnwinderFromPid unwinder(kMaxFrames, pid);
+  if (!unwinder.Init(unwindstack::Regs::CurrentArch())) {
+    LOG(FATAL) << "Failed to init unwinder object.";
   }
 
-  std::shared_ptr<Memory> process_memory = backtrace_map->GetProcessMemory();
-  engrave_tombstone(unique_fd(dup(tombstone_fd)), backtrace_map.get(), process_memory.get(),
-                    threads, tid, abort_msg_address, nullptr, nullptr);
+  engrave_tombstone(unique_fd(dup(tombstone_fd)), &unwinder, threads, tid, abort_msg_address,
+                    nullptr, nullptr);
 }
 
-void engrave_tombstone(unique_fd output_fd, BacktraceMap* map, Memory* process_memory,
+void engrave_tombstone(unique_fd output_fd, unwindstack::Unwinder* unwinder,
                        const std::map<pid_t, ThreadInfo>& threads, pid_t target_thread,
                        uint64_t abort_msg_address, OpenFilesList* open_files,
                        std::string* amfd_data) {
@@ -669,7 +678,7 @@ void engrave_tombstone(unique_fd output_fd, BacktraceMap* map, Memory* process_m
   if (it == threads.end()) {
     LOG(FATAL) << "failed to find target thread";
   }
-  dump_thread(&log, map, process_memory, it->second, abort_msg_address, true);
+  dump_thread(&log, unwinder, it->second, abort_msg_address, true);
 
   if (want_logs) {
     dump_logs(&log, it->second.pid, 50);
@@ -680,7 +689,7 @@ void engrave_tombstone(unique_fd output_fd, BacktraceMap* map, Memory* process_m
       continue;
     }
 
-    dump_thread(&log, map, process_memory, thread_info, 0, false);
+    dump_thread(&log, unwinder, thread_info, 0, false);
   }
 
   if (open_files) {