src/client/linux/minidump_writer/minidump_writer_unittest.cc

// Copyright (c) 2011 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,
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <fcntl.h>
#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

#include <string>

#include "breakpad_googletest_includes.h"
#include "client/linux/handler/exception_handler.h"
#include "client/linux/minidump_writer/linux_dumper.h"
#include "client/linux/minidump_writer/minidump_writer.h"
#include "common/linux/eintr_wrapper.h"
#include "common/linux/file_id.h"
#include "common/tests/auto_tempdir.h"
#include "google_breakpad/processor/minidump.h"

using namespace google_breakpad;

// Length of a formatted GUID string =
// sizeof(MDGUID) * 2 + 4 (for dashes) + 1 (null terminator)
const int kGUIDStringSize = 37;

namespace {
typedef testing::Test MinidumpWriterTest;
}

TEST(MinidumpWriterTest, Setup) {
  int fds[2];
  ASSERT_NE(-1, pipe(fds));

  const pid_t child = fork();
  if (child == 0) {
    close(fds[1]);
    char b;
    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
    close(fds[0]);
    syscall(__NR_exit);
  }
  close(fds[0]);

  ExceptionHandler::CrashContext context;
  memset(&context, 0, sizeof(context));

  AutoTempDir temp_dir;
  std::string templ = temp_dir.path() + "/minidump-writer-unittest";
  // Set a non-zero tid to avoid tripping asserts.
  context.tid = 1;
  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context)));
  struct stat st;
  ASSERT_EQ(stat(templ.c_str(), &st), 0);
  ASSERT_GT(st.st_size, 0u);

  close(fds[1]);
}

// Test that mapping info can be specified when writing a minidump,
// and that it ends up in the module list of the minidump.
TEST(MinidumpWriterTest, MappingInfo) {
  int fds[2];
  ASSERT_NE(-1, pipe(fds));

  // These are defined here so the parent can use them to check the
  // data from the minidump afterwards.
  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
  const char* kMemoryName = "a fake module";
  const u_int8_t kModuleGUID[sizeof(MDGUID)] = {
    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
  };
  char module_identifier_buffer[kGUIDStringSize];
  FileID::ConvertIdentifierToString(kModuleGUID,
                                    module_identifier_buffer,
                                    sizeof(module_identifier_buffer));
  string module_identifier(module_identifier_buffer);
  // Strip out dashes
  size_t pos;
  while ((pos = module_identifier.find('-')) != string::npos) {
    module_identifier.erase(pos, 1);
  }
  // And append a zero, because module IDs include an "age" field
  // which is always zero on Linux.
  module_identifier += "0";

  // Get some memory.
  char* memory =
    reinterpret_cast<char*>(mmap(NULL,
                                 kMemorySize,
                                 PROT_READ | PROT_WRITE,
                                 MAP_PRIVATE | MAP_ANON,
                                 -1,
                                 0));
  const u_int64_t kMemoryAddress = reinterpret_cast<u_int64_t>(memory);
  ASSERT_TRUE(memory);

  const pid_t child = fork();
  if (child == 0) {
    close(fds[1]);
    char b;
    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
    close(fds[0]);
    syscall(__NR_exit);
  }
  close(fds[0]);

  ExceptionHandler::CrashContext context;
  memset(&context, 0, sizeof(context));
  context.tid = 1;

  AutoTempDir temp_dir;
  std::string templ = temp_dir.path() + "/minidump-writer-unittest";

  // Add information about the mapped memory.
  MappingInfo info;
  info.start_addr = kMemoryAddress;
  info.size = kMemorySize;
  info.offset = 0;
  strcpy(info.name, kMemoryName);

  MappingList mappings;
  MappingEntry mapping;
  mapping.first = info;
  memcpy(mapping.second, kModuleGUID, sizeof(MDGUID));
  mappings.push_back(mapping);
  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
                            mappings));

  // Read the minidump. Load the module list, and ensure that
  // the mmap'ed |memory| is listed with the given module name
  // and debug ID.
  Minidump minidump(templ.c_str());
  ASSERT_TRUE(minidump.Read());

  MinidumpModuleList* module_list = minidump.GetModuleList();
  ASSERT_TRUE(module_list);
  const MinidumpModule* module =
    module_list->GetModuleForAddress(kMemoryAddress);
  ASSERT_TRUE(module);

  EXPECT_EQ(kMemoryAddress, module->base_address());
  EXPECT_EQ(kMemorySize, module->size());
  EXPECT_EQ(kMemoryName, module->code_file());
  EXPECT_EQ(module_identifier, module->debug_identifier());

  close(fds[1]);
}

// Test that mapping info can be specified, and that it overrides
// existing mappings that are wholly contained within the specified
// range.
TEST(MinidumpWriterTest, MappingInfoContained) {
  int fds[2];
  ASSERT_NE(-1, pipe(fds));

  // These are defined here so the parent can use them to check the
  // data from the minidump afterwards.
  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
  const char* kMemoryName = "a fake module";
  const u_int8_t kModuleGUID[sizeof(MDGUID)] = {
    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
  };
  char module_identifier_buffer[kGUIDStringSize];
  FileID::ConvertIdentifierToString(kModuleGUID,
                                    module_identifier_buffer,
                                    sizeof(module_identifier_buffer));
  string module_identifier(module_identifier_buffer);
  // Strip out dashes
  size_t pos;
  while ((pos = module_identifier.find('-')) != string::npos) {
    module_identifier.erase(pos, 1);
  }
  // And append a zero, because module IDs include an "age" field
  // which is always zero on Linux.
  module_identifier += "0";

  // mmap a file
  AutoTempDir temp_dir;
  std::string tempfile = temp_dir.path() + "/minidump-writer-unittest-temp";
  int fd = open(tempfile.c_str(), O_RDWR | O_CREAT, 0);
  ASSERT_NE(-1, fd);
  unlink(tempfile.c_str());
  // fill with zeros
  char buffer[kMemorySize];
  memset(buffer, 0, kMemorySize);
  ASSERT_EQ(kMemorySize, write(fd, buffer, kMemorySize));
  lseek(fd, 0, SEEK_SET);

  char* memory =
    reinterpret_cast<char*>(mmap(NULL,
                                 kMemorySize,
                                 PROT_READ | PROT_WRITE,
                                 MAP_PRIVATE,
                                 fd,
                                 0));
  const u_int64_t kMemoryAddress = reinterpret_cast<u_int64_t>(memory);
  ASSERT_TRUE(memory);
  close(fd);

  const pid_t child = fork();
  if (child == 0) {
    close(fds[1]);
    char b;
    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
    close(fds[0]);
    syscall(__NR_exit);
  }
  close(fds[0]);

  ExceptionHandler::CrashContext context;
  memset(&context, 0, sizeof(context));
  context.tid = 1;

  std::string dumpfile = temp_dir.path() + "/minidump-writer-unittest";

  // Add information about the mapped memory. Report it as being larger than
  // it actually is.
  MappingInfo info;
  info.start_addr = kMemoryAddress - kMemorySize;
  info.size = kMemorySize * 3;
  info.offset = 0;
  strcpy(info.name, kMemoryName);

  MappingList mappings;
  MappingEntry mapping;
  mapping.first = info;
  memcpy(mapping.second, kModuleGUID, sizeof(MDGUID));
  mappings.push_back(mapping);
  ASSERT_TRUE(
      WriteMinidump(dumpfile.c_str(), child, &context, sizeof(context),
                    mappings));

  // Read the minidump. Load the module list, and ensure that
  // the mmap'ed |memory| is listed with the given module name
  // and debug ID.
  Minidump minidump(dumpfile.c_str());
  ASSERT_TRUE(minidump.Read());

  MinidumpModuleList* module_list = minidump.GetModuleList();
  ASSERT_TRUE(module_list);
  const MinidumpModule* module =
    module_list->GetModuleForAddress(kMemoryAddress);
  ASSERT_TRUE(module);

  EXPECT_EQ(info.start_addr, module->base_address());
  EXPECT_EQ(info.size, module->size());
  EXPECT_EQ(kMemoryName, module->code_file());
  EXPECT_EQ(module_identifier, module->debug_identifier());

  close(fds[1]);
}

TEST(MinidumpWriterTest, DeletedBinary) {
  static const int kNumberOfThreadsInHelperProgram = 1;
  char kNumberOfThreadsArgument[2];
  sprintf(kNumberOfThreadsArgument, "%d", kNumberOfThreadsInHelperProgram);

  // Locate helper binary next to the current binary.
  char self_path[PATH_MAX];
  if (readlink("/proc/self/exe", self_path, sizeof(self_path) - 1) == -1) {
    FAIL() << "readlink failed: " << strerror(errno);
    exit(1);
  }
  string helper_path(self_path);
  size_t pos = helper_path.rfind('/');
  if (pos == string::npos) {
    FAIL() << "no trailing slash in path: " << helper_path;
    exit(1);
  }
  helper_path.erase(pos + 1);
  helper_path += "linux_dumper_unittest_helper";

  // Copy binary to a temp file.
  AutoTempDir temp_dir;
  std::string binpath = temp_dir.path() + "/linux-dumper-unittest-helper";
  char cmdline[2 * PATH_MAX];
  sprintf(cmdline, "/bin/cp \"%s\" \"%s\"", helper_path.c_str(),
          binpath.c_str());
  ASSERT_EQ(0, system(cmdline));
  ASSERT_EQ(0, chmod(binpath.c_str(), 0755));

  int fds[2];
  ASSERT_NE(-1, pipe(fds));

  pid_t child_pid = fork();
  if (child_pid == 0) {
    // In child process.
    close(fds[0]);

    // Pass the pipe fd and the number of threads as arguments.
    char pipe_fd_string[8];
    sprintf(pipe_fd_string, "%d", fds[1]);
    execl(binpath.c_str(),
          binpath.c_str(),
          pipe_fd_string,
          kNumberOfThreadsArgument,
          NULL);
  }
  close(fds[1]);
  // Wait for the child process to signal that it's ready.
  struct pollfd pfd;
  memset(&pfd, 0, sizeof(pfd));
  pfd.fd = fds[0];
  pfd.events = POLLIN | POLLERR;

  const int r = HANDLE_EINTR(poll(&pfd, 1, 1000));
  ASSERT_EQ(1, r);
  ASSERT_TRUE(pfd.revents & POLLIN);
  uint8_t junk;
  read(fds[0], &junk, sizeof(junk));
  close(fds[0]);

  // Child is ready now.
  // Unlink the test binary.
  unlink(binpath.c_str());

  ExceptionHandler::CrashContext context;
  memset(&context, 0, sizeof(context));

  std::string templ = temp_dir.path() + "/minidump-writer-unittest";
  // Set a non-zero tid to avoid tripping asserts.
  context.tid = 1;
  ASSERT_TRUE(WriteMinidump(templ.c_str(), child_pid, &context,
                            sizeof(context)));
  kill(child_pid, SIGKILL);

  struct stat st;
  ASSERT_EQ(stat(templ.c_str(), &st), 0);
  ASSERT_GT(st.st_size, 0u);



  Minidump minidump(templ.c_str());
  ASSERT_TRUE(minidump.Read());

  // Check that the main module filename is correct.
  MinidumpModuleList* module_list = minidump.GetModuleList();
  ASSERT_TRUE(module_list);
  const MinidumpModule* module = module_list->GetMainModule();
  EXPECT_STREQ(binpath.c_str(), module->code_file().c_str());
  // Check that the file ID is correct.
  FileID fileid(helper_path.c_str());
  uint8_t identifier[sizeof(MDGUID)];
  EXPECT_TRUE(fileid.ElfFileIdentifier(identifier));
  char identifier_string[kGUIDStringSize];
  FileID::ConvertIdentifierToString(identifier,
                                    identifier_string,
                                    kGUIDStringSize);
  string module_identifier(identifier_string);
  // Strip out dashes
  while ((pos = module_identifier.find('-')) != string::npos) {
    module_identifier.erase(pos, 1);
  }
  // And append a zero, because module IDs include an "age" field
  // which is always zero on Linux.
  module_identifier += "0";
  EXPECT_EQ(module_identifier, module->debug_identifier());
}