Added on-demand minidump generation for Linux, and a Linux test app.

A=brdevmn
R=mochalatte

Code review: http://breakpad.appspot.com/48001/show



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@451 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/handler/exception_handler.cc

@@ -77,12 +77,13 @@
 #include <sys/ucontext.h>
 #include <sys/user.h>
 #include <sys/wait.h>
+#include <ucontext.h>
 #include <unistd.h>
 
 #include "common/linux/linux_libc_support.h"
 #include "common/linux/linux_syscall_support.h"
 #include "common/linux/memory.h"
-#include "client/linux/minidump_writer//minidump_writer.h"
+#include "client/linux/minidump_writer/minidump_writer.h"
 #include "common/linux/guid_creator.h"
 
 // A wrapper for the tgkill syscall: send a signal to a specific thread.
@@ -274,6 +275,11 @@ bool ExceptionHandler::HandleSignal(int sig, siginfo_t* info, void* uc) {
                                        callback_context_))
     return true;
 
+  return GenerateDump(&context);
+}
+
+// This function may run in a compromised context: see the top of the file.
+bool ExceptionHandler::GenerateDump(CrashContext *context) {
   static const unsigned kChildStackSize = 8000;
   PageAllocator allocator;
   uint8_t* stack = (uint8_t*) allocator.Alloc(kChildStackSize);
@@ -286,8 +292,8 @@ bool ExceptionHandler::HandleSignal(int sig, siginfo_t* info, void* uc) {
   ThreadArgument thread_arg;
   thread_arg.handler = this;
   thread_arg.pid = getpid();
-  thread_arg.context = &context;
-  thread_arg.context_size = sizeof(context);
+  thread_arg.context = context;
+  thread_arg.context_size = sizeof(*context);
 
   const pid_t child = sys_clone(
       ThreadEntry, stack, CLONE_FILES | CLONE_FS | CLONE_UNTRACED,
@@ -298,7 +304,7 @@ bool ExceptionHandler::HandleSignal(int sig, siginfo_t* info, void* uc) {
   } while (r == -1 && errno == EINTR);
 
   if (r == -1) {
-    static const char msg[] = "ExceptionHandler::HandleSignal: waitpid failed:";
+    static const char msg[] = "ExceptionHandler::GenerateDump waitpid failed:";
     sys_write(2, msg, sizeof(msg) - 1);
     sys_write(2, strerror(errno), strlen(strerror(errno)));
     sys_write(2, "\n", 1);
@@ -321,4 +327,29 @@ bool ExceptionHandler::DoDump(pid_t crashing_process, const void* context,
       next_minidump_path_c_, crashing_process, context, context_size);
 }
 
+// static
+bool ExceptionHandler::WriteMinidump(const std::string &dump_path,
+                                     MinidumpCallback callback,
+                                     void* callback_context) {
+  ExceptionHandler eh(dump_path, NULL, callback, callback_context, false);
+  return eh.WriteMinidump();
+}
+
+bool ExceptionHandler::WriteMinidump() {
+  // Allow ourselves to be dumped.
+  sys_prctl(PR_SET_DUMPABLE, 1);
+
+  CrashContext context;
+  int getcontext_result = getcontext(&context.context);
+  if (getcontext_result)
+    return false;
+  memcpy(&context.float_state, context.context.uc_mcontext.fpregs,
+         sizeof(context.float_state));
+  context.tid = sys_gettid();
+
+  bool success = GenerateDump(&context);
+  UpdateNextID();
+  return success;
+}
+
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler.h

@@ -153,6 +153,7 @@ class ExceptionHandler {
   bool InstallHandlers();
   void UninstallHandlers();
   void PreresolveSymbols();
+  bool GenerateDump(CrashContext *context);
 
   void UpdateNextID();
   static void SignalHandler(int sig, siginfo_t* info, void* uc);

src/processor/testdata/linux_test_app.cc

@@ -0,0 +1,81 @@
+// Copyright (c) 2009, Google Inc.
+// 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.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// 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.
+
+// Breakpad test application for Linux. When run, it generates one on-demand
+// minidump and then crashes, which should generate an on-crash minidump.
+// dump_syms can be used to extract symbol information for use in processing.
+
+// To build:
+// g++ -g -o linux_test_app -I ../../ -L../../client/linux linux_test_app.cc \
+//   -lbreakpad
+// Add -m32 to build a 32-bit executable, or -m64 for a 64-bit one
+// (assuming your environment supports it). Replace -g with -gstabs+ to
+// generate an executable with STABS symbols (needs -m32), or -gdwarf-2 for one
+// with DWARF symbols (32- or 64-bit)
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <cstdio>
+#include <string>
+
+#include "common/linux/linux_syscall_support.h"
+#include "client/linux/handler/exception_handler.h"
+
+namespace {
+
+// google_breakpad::MinidumpCallback to invoke after minidump generation.
+static bool callback(const char *dump_path, const char *id,
+                     void *context,
+                     bool succeeded) {
+  if (succeeded) {
+    printf("dump guid is %s\n", id);
+  } else {
+    printf("dump failed\n");
+  }
+  fflush(stdout);
+
+  return succeeded;
+}
+
+static void CrashFunction() {
+  int *i = reinterpret_cast<int*>(0x45);
+  *i = 5;  // crash!
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  google_breakpad::ExceptionHandler eh(".", NULL, callback, NULL, true);
+  if (!eh.WriteMinidump()) {
+    printf("Failed to generate on-demand minidump\n");
+  }
+  CrashFunction();
+  printf("did not crash?\n");
+  return 0;
+}