Print the build id of shared libraries if present.

For every map that has a name, and if it's a mapped in shared library,
print the build id.

Refactor the way dump_all_maps logs data.

Refactor the way stack segments are dumped.

Bug: 19371018
Change-Id: Ic08d05a4b13f128925743936fb84d8059f7cb56f

4 files changed, 229 insertions, 61 deletions

diff --git a/debuggerd/Android.mk b/debuggerd/Android.mk
index 8cc4682..dd53296 100644
--- a/debuggerd/Android.mk
+++ b/debuggerd/Android.mk
@@ -5,6 +5,7 @@ include $(CLEAR_VARS)
 LOCAL_SRC_FILES:= \
     backtrace.cpp \
     debuggerd.cpp \
+    elf_utils.cpp \
     getevent.cpp \
     tombstone.cpp \
     utility.cpp \
@@ -28,6 +29,7 @@ endif
 
 LOCAL_SHARED_LIBRARIES := \
     libbacktrace \
+    libbase \
     libcutils \
     liblog \
     libselinux \
@@ -38,7 +40,6 @@ LOCAL_MODULE := debuggerd
 LOCAL_MODULE_STEM_32 := debuggerd
 LOCAL_MODULE_STEM_64 := debuggerd64
 LOCAL_MULTILIB := both
-LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
 
 include $(BUILD_EXECUTABLE)
 
diff --git a/debuggerd/elf_utils.cpp b/debuggerd/elf_utils.cpp
new file mode 100644
index 0000000..764b9db
--- /dev/null
+++ b/debuggerd/elf_utils.cpp
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2015 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 <elf.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <string>
+
+#include <backtrace/Backtrace.h>
+#include <base/stringprintf.h>
+#include <log/log.h>
+
+#include "elf_utils.h"
+
+template <typename HdrType, typename PhdrType, typename NhdrType>
+static bool get_build_id(
+    Backtrace* backtrace, uintptr_t base_addr, uint8_t* e_ident, std::string* build_id) {
+  HdrType hdr;
+
+  memcpy(&hdr.e_ident[0], e_ident, EI_NIDENT);
+
+  // First read the rest of the header.
+  if (backtrace->Read(base_addr + EI_NIDENT, reinterpret_cast<uint8_t*>(&hdr) + EI_NIDENT,
+                      sizeof(HdrType) - EI_NIDENT) != sizeof(HdrType) - EI_NIDENT) {
+    return false;
+  }
+
+  for (size_t i = 0; i < hdr.e_phnum; i++) {
+    PhdrType phdr;
+    if (backtrace->Read(base_addr + hdr.e_phoff + i * hdr.e_phentsize,
+                        reinterpret_cast<uint8_t*>(&phdr), sizeof(phdr)) != sizeof(phdr)) {
+      return false;
+    }
+    // Looking for the .note.gnu.build-id note.
+    if (phdr.p_type == PT_NOTE) {
+      size_t hdr_size = phdr.p_filesz;
+      uintptr_t addr = base_addr + phdr.p_offset;
+      while (hdr_size >= sizeof(NhdrType)) {
+        NhdrType nhdr;
+        if (backtrace->Read(addr, reinterpret_cast<uint8_t*>(&nhdr), sizeof(nhdr)) != sizeof(nhdr)) {
+          return false;
+        }
+        addr += sizeof(nhdr);
+        if (nhdr.n_type == NT_GNU_BUILD_ID) {
+          // Skip the name (which is the owner and should be "GNU").
+          addr += nhdr.n_namesz;
+          uint8_t build_id_data[128];
+          if (nhdr.n_namesz > sizeof(build_id_data)) {
+            ALOGE("Possible corrupted note, name size value is too large: %u",
+                  nhdr.n_namesz);
+            return false;
+          }
+          if (backtrace->Read(addr, build_id_data, nhdr.n_descsz) != nhdr.n_descsz) {
+            return false;
+          }
+
+          build_id->clear();
+          for (size_t bytes = 0; bytes < nhdr.n_descsz; bytes++) {
+            *build_id += android::base::StringPrintf("%02x", build_id_data[bytes]);
+          }
+
+          return true;
+        } else {
+          // Move past the extra note data.
+          hdr_size -= sizeof(nhdr);
+          size_t skip_bytes = nhdr.n_namesz + nhdr.n_descsz;
+          addr += skip_bytes;
+          if (hdr_size < skip_bytes) {
+            break;
+          }
+          hdr_size -= skip_bytes;
+        }
+      }
+    }
+  }
+  return false;
+}
+
+bool elf_get_build_id(Backtrace* backtrace, uintptr_t addr, std::string* build_id) {
+  // Read and verify the elf magic number first.
+  uint8_t e_ident[EI_NIDENT];
+  if (backtrace->Read(addr, e_ident, SELFMAG) != SELFMAG) {
+    return false;
+  }
+
+  if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
+    return false;
+  }
+
+  // Read the rest of EI_NIDENT.
+  if (backtrace->Read(addr + SELFMAG, e_ident + SELFMAG, EI_NIDENT - SELFMAG) != EI_NIDENT - SELFMAG) {
+    return false;
+  }
+
+  if (e_ident[EI_CLASS] == ELFCLASS32) {
+    return get_build_id<Elf32_Ehdr, Elf32_Phdr, Elf32_Nhdr>(backtrace, addr, e_ident, build_id);
+  } else if (e_ident[EI_CLASS] == ELFCLASS64) {
+    return get_build_id<Elf64_Ehdr, Elf64_Phdr, Elf64_Nhdr>(backtrace, addr, e_ident, build_id);
+  }
+
+  return false;
+}
diff --git a/debuggerd/elf_utils.h b/debuggerd/elf_utils.h
new file mode 100644
index 0000000..11d0a43
--- /dev/null
+++ b/debuggerd/elf_utils.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef _DEBUGGERD_ELF_UTILS_H
+#define _DEBUGGERD_ELF_UTILS_H
+
+#include <stdint.h>
+#include <string>
+
+class Backtrace;
+
+bool elf_get_build_id(Backtrace*, uintptr_t, std::string*);
+
+#endif // _DEBUGGERD_ELF_UTILS_H
diff --git a/debuggerd/tombstone.cpp b/debuggerd/tombstone.cpp
index e927ea3..094ab48 100644
--- a/debuggerd/tombstone.cpp
+++ b/debuggerd/tombstone.cpp
@@ -34,6 +34,7 @@
 
 #include <private/android_filesystem_config.h>
 
+#include <base/stringprintf.h>
 #include <cutils/properties.h>
 #include <log/log.h>
 #include <log/logger.h>
@@ -46,9 +47,12 @@
 
 #include <UniquePtr.h>
 
+#include <string>
+
+#include "backtrace.h"
+#include "elf_utils.h"
 #include "machine.h"
 #include "tombstone.h"
-#include "backtrace.h"
 
 #define STACK_WORDS 16
 
@@ -234,47 +238,36 @@ static void dump_thread_info(log_t* log, pid_t pid, pid_t tid) {
 
 static void dump_stack_segment(
     Backtrace* backtrace, log_t* log, uintptr_t* sp, size_t words, int label) {
+  // Read the data all at once.
+  word_t stack_data[words];
+  size_t bytes_read = backtrace->Read(*sp, reinterpret_cast<uint8_t*>(&stack_data[0]), sizeof(word_t) * words);
+  words = bytes_read / sizeof(word_t);
+  std::string line;
   for (size_t i = 0; i < words; i++) {
-    word_t stack_content;
-    if (!backtrace->ReadWord(*sp, &stack_content)) {
-      break;
+    line = "    ";
+    if (i == 0 && label >= 0) {
+      // Print the label once.
+      line += android::base::StringPrintf("#%02d  ", label);
+    } else {
+      line += "     ";
     }
+    line += android::base::StringPrintf("%" PRIPTR "  %" PRIPTR, *sp, stack_data[i]);
 
     backtrace_map_t map;
-    backtrace->FillInMap(stack_content, &map);
-    std::string map_name;
-    if (BacktraceMap::IsValid(map) && map.name.length() > 0) {
-      map_name = "  " + map.name;
-    }
-    uintptr_t offset = 0;
-    std::string func_name(backtrace->GetFunctionName(stack_content, &offset));
-    if (!func_name.empty()) {
-      if (!i && label >= 0) {
+    backtrace->FillInMap(stack_data[i], &map);
+    if (BacktraceMap::IsValid(map) && !map.name.empty()) {
+      line += "  " + map.name;
+      uintptr_t offset = 0;
+      std::string func_name(backtrace->GetFunctionName(stack_data[i], &offset));
+      if (!func_name.empty()) {
+        line += " (" + func_name;
         if (offset) {
-          _LOG(log, logtype::STACK, "    #%02d  %" PRIPTR "  %" PRIPTR "%s (%s+%" PRIuPTR ")\n",
-               label, *sp, stack_content, map_name.c_str(), func_name.c_str(), offset);
-        } else {
-          _LOG(log, logtype::STACK, "    #%02d  %" PRIPTR "  %" PRIPTR "%s (%s)\n",
-               label, *sp, stack_content, map_name.c_str(), func_name.c_str());
+          line += android::base::StringPrintf("+%" PRIuPTR, offset);
         }
-      } else {
-        if (offset) {
-          _LOG(log, logtype::STACK, "         %" PRIPTR "  %" PRIPTR "%s (%s+%" PRIuPTR ")\n",
-               *sp, stack_content, map_name.c_str(), func_name.c_str(), offset);
-        } else {
-          _LOG(log, logtype::STACK, "         %" PRIPTR "  %" PRIPTR "%s (%s)\n",
-               *sp, stack_content, map_name.c_str(), func_name.c_str());
-        }
-      }
-    } else {
-      if (!i && label >= 0) {
-        _LOG(log, logtype::STACK, "    #%02d  %" PRIPTR "  %" PRIPTR "%s\n",
-             label, *sp, stack_content, map_name.c_str());
-      } else {
-        _LOG(log, logtype::STACK, "         %" PRIPTR "  %" PRIPTR "%s\n",
-             *sp, stack_content, map_name.c_str());
+        line += ')';
       }
     }
+    _LOG(log, logtype::STACK, "%s\n", line.c_str());
 
     *sp += sizeof(word_t);
   }
@@ -325,44 +318,72 @@ static void dump_stack(Backtrace* backtrace, log_t* log) {
   }
 }
 
-static void dump_map(log_t* log, const backtrace_map_t* map, bool fault_addr) {
-  _LOG(log, logtype::MAPS, "%s%" PRIPTR "-%" PRIPTR " %c%c%c  %7" PRIdPTR "%s\n",
-         (fault_addr? "--->" : "    "), map->start, map->end - 1,
-         (map->flags & PROT_READ) ? 'r' : '-', (map->flags & PROT_WRITE) ? 'w' : '-',
-         (map->flags & PROT_EXEC) ? 'x' : '-',
-         (map->end - map->start),
-         (map->name.length() > 0) ? ("  " + map->name).c_str() : "");
-}
-
-static void dump_all_maps(BacktraceMap* map, log_t* log, pid_t tid) {
-  bool has_fault_address = false;
+static void dump_all_maps(Backtrace* backtrace, BacktraceMap* map, log_t* log, pid_t tid) {
+  bool print_fault_address_marker = false;
   uintptr_t addr = 0;
   siginfo_t si;
   memset(&si, 0, sizeof(si));
   if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si)) {
-    _LOG(log, logtype::MAPS, "cannot get siginfo for %d: %s\n", tid, strerror(errno));
+    _LOG(log, logtype::ERROR, "cannot get siginfo for %d: %s\n", tid, strerror(errno));
   } else {
-    has_fault_address = signal_has_si_addr(si.si_signo);
+    print_fault_address_marker = signal_has_si_addr(si.si_signo);
     addr = reinterpret_cast<uintptr_t>(si.si_addr);
   }
 
-  _LOG(log, logtype::MAPS, "\nmemory map:%s\n", has_fault_address ? " (fault address prefixed with --->)" : "");
-
-  if (has_fault_address && (addr < map->begin()->start)) {
-    _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " before any mapped regions\n", addr);
+  _LOG(log, logtype::MAPS, "\n");
+  if (!print_fault_address_marker) {
+    _LOG(log, logtype::MAPS, "memory map:\n");
+  } else {
+    _LOG(log, logtype::MAPS, "memory map: (fault address prefixed with --->)\n");
+    if (map->begin() != map->end() && addr < map->begin()->start) {
+      _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " before any mapped regions\n",
+           addr);
+      print_fault_address_marker = false;
+    }
   }
 
-  BacktraceMap::const_iterator prev = map->begin();
+  std::string line;
   for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
-    if (addr >= (*prev).end && addr < (*it).start) {
-      _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " between mapped regions\n", addr);
+    line = "    ";
+    if (print_fault_address_marker) {
+      if (addr < it->start) {
+        _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " between mapped regions\n",
+             addr);
+        print_fault_address_marker = false;
+      } else if (addr >= it->start && addr < it->end) {
+        line = "--->";
+        print_fault_address_marker = false;
+      }
+    }
+    line += android::base::StringPrintf("%" PRIPTR "-%" PRIPTR " ", it->start, it->end - 1);
+    if (it->flags & PROT_READ) {
+      line += 'r';
+    } else {
+      line += '-';
+    }
+    if (it->flags & PROT_WRITE) {
+      line += 'w';
+    } else {
+      line += '-';
+    }
+    if (it->flags & PROT_EXEC) {
+      line += 'x';
+    } else {
+      line += '-';
+    }
+    line += android::base::StringPrintf("  %8" PRIxPTR, it->end - it->start);
+    if (it->name.length() > 0) {
+      line += "  " + it->name;
+      std::string build_id;
+      if ((it->flags & PROT_READ) && elf_get_build_id(backtrace, it->start, &build_id)) {
+        line += " (BuildId: " + build_id + ")";
+      }
     }
-    prev = it;
-    bool in_map = has_fault_address && (addr >= (*it).start) && (addr < (*it).end);
-    dump_map(log, &*it, in_map);
+    _LOG(log, logtype::MAPS, "%s\n", line.c_str());
   }
-  if (has_fault_address && (addr >= (*prev).end)) {
-    _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " after any mapped regions\n", addr);
+  if (print_fault_address_marker) {
+    _LOG(log, logtype::MAPS, "--->Fault address falls at %" PRIPTR " after any mapped regions\n",
+        addr);
   }
 }
 
@@ -627,7 +648,7 @@ static bool dump_crash(log_t* log, pid_t pid, pid_t tid, int signal, int si_code
     dump_backtrace_and_stack(backtrace.get(), log);
   }
   dump_memory_and_code(log, tid);
-  dump_all_maps(map.get(), log, tid);
+  dump_all_maps(backtrace.get(), map.get(), log, tid);
 
   if (want_logs) {
     dump_logs(log, pid, 5);