Lose debuggerd client code to libdebuggerd_client.

Bug: http://b/24414818
Change-Id: I524714e081a27df4d2046f0c8eb853a1b20592e6

4 files changed, 17 insertions, 327 deletions

diff --git a/linker/Android.mk b/linker/Android.mk
index c37d6db67..29520f9e2 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -19,7 +19,6 @@ include $(CLEAR_VARS)
 LOCAL_CLANG := true
 
 LOCAL_SRC_FILES := \
-    debugger.cpp \
     dlfcn.cpp \
     linker.cpp \
     linker_block_allocator.cpp \
@@ -76,7 +75,14 @@ LOCAL_ASFLAGS := $(LOCAL_CFLAGS)
 
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 
-LOCAL_STATIC_LIBRARIES := libc_nomalloc libziparchive libutils libbase libz liblog
+LOCAL_STATIC_LIBRARIES := \
+    libc_nomalloc \
+    libziparchive \
+    libutils \
+    libbase \
+    libz \
+    liblog \
+    libdebuggerd_client
 
 # Important: The liblinker_malloc should be the last library in the list
 # to overwrite any other malloc implementations by other static libraries.
diff --git a/linker/debugger.cpp b/linker/debugger.cpp
deleted file mode 100644
index d4c7928f5..000000000
--- a/linker/debugger.cpp
+++ /dev/null
@@ -1,321 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include "linker.h"
-#include "linker_gdb_support.h"
-
-#include <errno.h>
-#include <inttypes.h>
-#include <pthread.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/mman.h>
-#include <sys/prctl.h>
-#include <sys/socket.h>
-#include <sys/syscall.h>
-#include <sys/un.h>
-#include <unistd.h>
-
-extern "C" int tgkill(int tgid, int tid, int sig);
-
-// Crash actions have to be sent to the proper debuggerd.
-// On 64 bit systems, the 32 bit debuggerd is named differently.
-#if defined(TARGET_IS_64_BIT) && !defined(__LP64__)
-#define DEBUGGER_SOCKET_NAME "android:debuggerd32"
-#else
-#define DEBUGGER_SOCKET_NAME "android:debuggerd"
-#endif
-
-enum debugger_action_t {
-  // dump a crash
-  DEBUGGER_ACTION_CRASH,
-  // dump a tombstone file
-  DEBUGGER_ACTION_DUMP_TOMBSTONE,
-  // dump a backtrace only back to the socket
-  DEBUGGER_ACTION_DUMP_BACKTRACE,
-};
-
-// Message sent over the socket.
-// NOTE: Any changes to this structure must also be reflected in
-//       system/core/include/cutils/debugger.h.
-struct __attribute__((packed)) debugger_msg_t {
-  int32_t action;
-  pid_t tid;
-  uint64_t abort_msg_address;
-  int32_t original_si_code;
-};
-
-// see man(2) prctl, specifically the section about PR_GET_NAME
-#define MAX_TASK_NAME_LEN (16)
-
-static int socket_abstract_client(const char* name, int type) {
-  sockaddr_un addr;
-
-  // Test with length +1 for the *initial* '\0'.
-  size_t namelen = strlen(name);
-  if ((namelen + 1) > sizeof(addr.sun_path)) {
-    errno = EINVAL;
-    return -1;
-  }
-
-  // This is used for abstract socket namespace, we need
-  // an initial '\0' at the start of the Unix socket path.
-  //
-  // Note: The path in this case is *not* supposed to be
-  // '\0'-terminated. ("man 7 unix" for the gory details.)
-  memset(&addr, 0, sizeof(addr));
-  addr.sun_family = AF_LOCAL;
-  addr.sun_path[0] = 0;
-  memcpy(addr.sun_path + 1, name, namelen);
-
-  socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
-
-  int s = socket(AF_LOCAL, type, 0);
-  if (s == -1) {
-    return -1;
-  }
-
-  int rc = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen));
-  if (rc == -1) {
-    close(s);
-    return -1;
-  }
-
-  return s;
-}
-
-/*
- * Writes a summary of the signal to the log file.  We do this so that, if
- * for some reason we're not able to contact debuggerd, there is still some
- * indication of the failure in the log.
- *
- * We could be here as a result of native heap corruption, or while a
- * mutex is being held, so we don't want to use any libc functions that
- * could allocate memory or hold a lock.
- */
-static void log_signal_summary(int signum, const siginfo_t* info) {
-  const char* signal_name = "???";
-  bool has_address = false;
-  switch (signum) {
-    case SIGABRT:
-      signal_name = "SIGABRT";
-      break;
-    case SIGBUS:
-      signal_name = "SIGBUS";
-      has_address = true;
-      break;
-    case SIGFPE:
-      signal_name = "SIGFPE";
-      has_address = true;
-      break;
-    case SIGILL:
-      signal_name = "SIGILL";
-      has_address = true;
-      break;
-    case SIGSEGV:
-      signal_name = "SIGSEGV";
-      has_address = true;
-      break;
-#if defined(SIGSTKFLT)
-    case SIGSTKFLT:
-      signal_name = "SIGSTKFLT";
-      break;
-#endif
-    case SIGTRAP:
-      signal_name = "SIGTRAP";
-      break;
-  }
-
-  char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
-  if (prctl(PR_GET_NAME, reinterpret_cast<unsigned long>(thread_name), 0, 0, 0) != 0) {
-    strcpy(thread_name, "<name unknown>");
-  } else {
-    // short names are null terminated by prctl, but the man page
-    // implies that 16 byte names are not.
-    thread_name[MAX_TASK_NAME_LEN] = 0;
-  }
-
-  // "info" will be null if the siginfo_t information was not available.
-  // Many signals don't have an address or a code.
-  char code_desc[32]; // ", code -6"
-  char addr_desc[32]; // ", fault addr 0x1234"
-  addr_desc[0] = code_desc[0] = 0;
-  if (info != nullptr) {
-    // For a rethrown signal, this si_code will be right and the one debuggerd shows will
-    // always be SI_TKILL.
-    __libc_format_buffer(code_desc, sizeof(code_desc), ", code %d", info->si_code);
-    if (has_address) {
-      __libc_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p", info->si_addr);
-    }
-  }
-  __libc_format_log(ANDROID_LOG_FATAL, "libc",
-                    "Fatal signal %d (%s)%s%s in tid %d (%s)",
-                    signum, signal_name, code_desc, addr_desc, gettid(), thread_name);
-}
-
-/*
- * Returns true if the handler for signal "signum" has SA_SIGINFO set.
- */
-static bool have_siginfo(int signum) {
-  struct sigaction old_action, new_action;
-
-  memset(&new_action, 0, sizeof(new_action));
-  new_action.sa_handler = SIG_DFL;
-  new_action.sa_flags = SA_RESTART;
-  sigemptyset(&new_action.sa_mask);
-
-  if (sigaction(signum, &new_action, &old_action) < 0) {
-    __libc_format_log(ANDROID_LOG_WARN, "libc", "Failed testing for SA_SIGINFO: %s",
-                      strerror(errno));
-    return false;
-  }
-  bool result = (old_action.sa_flags & SA_SIGINFO) != 0;
-
-  if (sigaction(signum, &old_action, nullptr) == -1) {
-    __libc_format_log(ANDROID_LOG_WARN, "libc", "Restore failed in test for SA_SIGINFO: %s",
-                      strerror(errno));
-  }
-  return result;
-}
-
-static void send_debuggerd_packet(siginfo_t* info) {
-  // Mutex to prevent multiple crashing threads from trying to talk
-  // to debuggerd at the same time.
-  static pthread_mutex_t crash_mutex = PTHREAD_MUTEX_INITIALIZER;
-  int ret = pthread_mutex_trylock(&crash_mutex);
-  if (ret != 0) {
-    if (ret == EBUSY) {
-      __libc_format_log(ANDROID_LOG_INFO, "libc",
-          "Another thread contacted debuggerd first; not contacting debuggerd.");
-      // This will never complete since the lock is never released.
-      pthread_mutex_lock(&crash_mutex);
-    } else {
-      __libc_format_log(ANDROID_LOG_INFO, "libc",
-                        "pthread_mutex_trylock failed: %s", strerror(ret));
-    }
-    return;
-  }
-
-  int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM | SOCK_CLOEXEC);
-  if (s == -1) {
-    __libc_format_log(ANDROID_LOG_FATAL, "libc", "Unable to open connection to debuggerd: %s",
-                      strerror(errno));
-    return;
-  }
-
-  // debuggerd knows our pid from the credentials on the
-  // local socket but we need to tell it the tid of the crashing thread.
-  // debuggerd will be paranoid and verify that we sent a tid
-  // that's actually in our process.
-  debugger_msg_t msg;
-  msg.action = DEBUGGER_ACTION_CRASH;
-  msg.tid = gettid();
-  msg.abort_msg_address = reinterpret_cast<uintptr_t>(g_abort_message);
-  msg.original_si_code = (info != nullptr) ? info->si_code : 0;
-  ret = TEMP_FAILURE_RETRY(write(s, &msg, sizeof(msg)));
-  if (ret == sizeof(msg)) {
-    char debuggerd_ack;
-    ret = TEMP_FAILURE_RETRY(read(s, &debuggerd_ack, 1));
-    int saved_errno = errno;
-    notify_gdb_of_libraries();
-    errno = saved_errno;
-  } else {
-    // read or write failed -- broken connection?
-    __libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s",
-                      strerror(errno));
-  }
-
-  close(s);
-}
-
-/*
- * Catches fatal signals so we can ask debuggerd to ptrace us before
- * we crash.
- */
-static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void*) {
-  // It's possible somebody cleared the SA_SIGINFO flag, which would mean
-  // our "info" arg holds an undefined value.
-  if (!have_siginfo(signal_number)) {
-    info = nullptr;
-  }
-
-  log_signal_summary(signal_number, info);
-
-  send_debuggerd_packet(info);
-
-  // We need to return from the signal handler so that debuggerd can dump the
-  // thread that crashed, but returning here does not guarantee that the signal
-  // will be thrown again, even for SIGSEGV and friends, since the signal could
-  // have been sent manually. Resend the signal with rt_tgsigqueueinfo(2) to
-  // preserve the SA_SIGINFO contents.
-  signal(signal_number, SIG_DFL);
-
-  struct siginfo si;
-  if (!info) {
-    memset(&si, 0, sizeof(si));
-    si.si_code = SI_USER;
-    si.si_pid = getpid();
-    si.si_uid = getuid();
-    info = &si;
-  } else if (info->si_code >= 0 || info->si_code == SI_TKILL) {
-    // rt_tgsigqueueinfo(2)'s documentation appears to be incorrect on kernels
-    // that contain commit 66dd34a (3.9+). The manpage claims to only allow
-    // negative si_code values that are not SI_TKILL, but 66dd34a changed the
-    // check to allow all si_code values in calls coming from inside the house.
-  }
-
-  int rc = syscall(SYS_rt_tgsigqueueinfo, getpid(), gettid(), signal_number, info);
-  if (rc != 0) {
-    __libc_format_log(ANDROID_LOG_FATAL, "libc", "failed to resend signal during crash: %s",
-                      strerror(errno));
-    _exit(0);
-  }
-}
-
-__LIBC_HIDDEN__ void debuggerd_init() {
-  struct sigaction action;
-  memset(&action, 0, sizeof(action));
-  sigemptyset(&action.sa_mask);
-  action.sa_sigaction = debuggerd_signal_handler;
-  action.sa_flags = SA_RESTART | SA_SIGINFO;
-
-  // Use the alternate signal stack if available so we can catch stack overflows.
-  action.sa_flags |= SA_ONSTACK;
-
-  sigaction(SIGABRT, &action, nullptr);
-  sigaction(SIGBUS, &action, nullptr);
-  sigaction(SIGFPE, &action, nullptr);
-  sigaction(SIGILL, &action, nullptr);
-  sigaction(SIGSEGV, &action, nullptr);
-#if defined(SIGSTKFLT)
-  sigaction(SIGSTKFLT, &action, nullptr);
-#endif
-  sigaction(SIGTRAP, &action, nullptr);
-}
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 9eb3a65c7..8f51533cf 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -61,6 +61,7 @@
 #include "linker_utils.h"
 
 #include "android-base/strings.h"
+#include "debuggerd/client.h"
 #include "ziparchive/zip_archive.h"
 
 extern void __libc_init_globals(KernelArgumentBlock&);
@@ -4060,7 +4061,14 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
   // Initialize system properties
   __system_properties_init(); // may use 'environ'
 
-  debuggerd_init();
+  // Register the debuggerd signal handler.
+  debuggerd_callbacks_t callbacks = {
+    .get_abort_message = []() {
+      return g_abort_message;
+    },
+    .post_dump = &notify_gdb_of_libraries,
+  };
+  debuggerd_init(&callbacks);
 
   // Get a few environment variables.
   const char* LD_DEBUG = getenv("LD_DEBUG");
diff --git a/linker/linker.h b/linker/linker.h
index 6eab00c3e..fbd236ff7 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -461,9 +461,6 @@ bool do_dlsym(void* handle, const char* sym_name, const char* sym_ver,
 
 int do_dladdr(const void* addr, Dl_info* info);
 
-void debuggerd_init();
-extern "C" abort_msg_t* g_abort_message;
-
 char* linker_get_error_buffer();
 size_t linker_get_error_buffer_size();