Add MachOImageReader and its test

util/mac/mach_o_image_reader_test.cc

+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// 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.
+
+#include "util/mac/mach_o_image_reader.h"
+
+#include <dlfcn.h>
+#include <mach-o/dyld_images.h>
+#include <mach-o/getsect.h>
+#include <mach-o/loader.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "base/strings/stringprintf.h"
+#include "build/build_config.h"
+#include "gtest/gtest.h"
+#include "util/mac/mach_o_image_segment_reader.h"
+#include "util/mac/process_reader.h"
+#include "util/mac/process_types.h"
+#include "util/misc/uuid.h"
+
+extern "C" {
+const struct dyld_all_image_infos* _dyld_get_all_image_infos();

[Robert Sesek, 2014/09/04 13:18:42]

Move this to a shared header? I've seen it before I think.

+}  // extern "C"
+
+namespace {
+
+using namespace crashpad;
+
+// Native types and constants, in cases where the 32-bit and 64-bit versions
+// are different.
+#if defined(ARCH_CPU_64_BITS)
+typedef mach_header_64 MachHeader;
+const uint32_t kMachMagic = MH_MAGIC_64;
+typedef segment_command_64 SegmentCommand;
+const uint32_t kSegmentCommand = LC_SEGMENT_64;
+typedef section_64 Section;
+#else
+typedef mach_header MachHeader;
+const uint32_t kMachMagic = MH_MAGIC;
+typedef segment_command SegmentCommand;
+const uint32_t kSegmentCommand = LC_SEGMENT;
+typedef section Section;
+#endif
+
+#if defined(ARCH_CPU_X86_64)
+const int kCPUType = CPU_TYPE_X86_64;
+#elif defined(ARCH_CPU_X86)
+const int kCPUType = CPU_TYPE_X86;
+#endif
+
+// Verifies that |expect_section| and |actual_section| agree.
+void ExpectSection(const Section* expect_section,
+                   const process_types::section* actual_section) {
+  ASSERT_TRUE(expect_section);
+  ASSERT_TRUE(actual_section);
+
+  EXPECT_EQ(
+      MachOImageSegmentReader::SectionNameString(expect_section->sectname),
+      MachOImageSegmentReader::SectionNameString(actual_section->sectname));
+  EXPECT_EQ(
+      MachOImageSegmentReader::SegmentNameString(expect_section->segname),
+      MachOImageSegmentReader::SegmentNameString(actual_section->segname));
+  EXPECT_EQ(expect_section->addr, actual_section->addr);
+  EXPECT_EQ(expect_section->size, actual_section->size);
+  EXPECT_EQ(expect_section->offset, actual_section->offset);
+  EXPECT_EQ(expect_section->align, actual_section->align);
+  EXPECT_EQ(expect_section->reloff, actual_section->reloff);
+  EXPECT_EQ(expect_section->nreloc, actual_section->nreloc);
+  EXPECT_EQ(expect_section->flags, actual_section->flags);
+  EXPECT_EQ(expect_section->reserved1, actual_section->reserved1);
+  EXPECT_EQ(expect_section->reserved2, actual_section->reserved2);
+}
+
+// Verifies that |expect_segment| is a valid Mach-O segment load command for the
+// current system by checking its |cmd| field. Then, verifies that the
+// information in |actual_segment| matches that in |expect_segment|. The
+// |segname|, |vmaddr|, |vmsize|, and |fileoff| fields are examined. Each
+// section within the segment is also examined by calling ExpectSection().
+// Access to each section via both MachOImageSegmentReader::GetSectionByName()
+// and MachOImageReader::GetSectionByName() is verified, expecting that each
+// call produces the same section. Segment and section data addresses are
+// verified against data obtained by calling getsegmentdata() and
+// getsectiondata(). The segment is checked to make sure that it behaves
+// correctly when attempting to look up a nonexistent section by name.
+// |section_index| is used to track the last-used section index in an image on
+// entry, and is reset to the last-used section index on return after the
+// sections are processed. This is used to test that
+// MachOImageReader::GetSectionAtIndex() returns the correct result.
+void ExpectSegmentCommand(const SegmentCommand* expect_segment,
+                          const MachHeader* expect_image,
+                          const MachOImageSegmentReader* actual_segment,
+                          mach_vm_address_t actual_segment_address,
+                          mach_vm_size_t actual_segment_size,
+                          const MachOImageReader* actual_image,
+                          size_t* section_index) {
+  ASSERT_TRUE(expect_segment);
+  ASSERT_TRUE(actual_segment);
+
+  EXPECT_EQ(kSegmentCommand, expect_segment->cmd);
+
+  std::string segment_name = actual_segment->Name();
+  EXPECT_EQ(MachOImageSegmentReader::SegmentNameString(expect_segment->segname),
+            segment_name);
+  EXPECT_EQ(expect_segment->vmaddr, actual_segment->vmaddr());
+  EXPECT_EQ(expect_segment->vmsize, actual_segment->vmsize());
+  EXPECT_EQ(expect_segment->fileoff, actual_segment->fileoff());
+
+  if (actual_segment->SegmentSlides()) {
+    EXPECT_EQ(actual_segment_address,
+              actual_segment->vmaddr() + actual_image->Slide());
+
+    unsigned long expect_segment_size;
+    const uint8_t* expect_segment_data = getsegmentdata(
+        expect_image, segment_name.c_str(), &expect_segment_size);
+    mach_vm_address_t expect_segment_address =
+        reinterpret_cast<mach_vm_address_t>(expect_segment_data);
+    EXPECT_EQ(expect_segment_address, actual_segment_address);
+    EXPECT_EQ(expect_segment_size, actual_segment->vmsize());
+    EXPECT_EQ(actual_segment->vmsize(), actual_segment_size);
+  } else {
+    // getsegmentdata() doesn’t return appropriate data for the __PAGEZERO
+    // segment because getsegmentdata() always adjusts for slide, but the
+    // __PAGEZERO segment never slides, it just grows. Skip the getsegmentdata()
+    // check for that segment according to the same rules that the kernel uses
+    // to identify __PAGEZERO. See 10.9.4 xnu-2422.110.17/bsd/kern/mach_loader.c
+    // load_segment().
+    EXPECT_EQ(actual_segment_address, actual_segment->vmaddr());
+    EXPECT_EQ(actual_segment->vmsize() + actual_image->Slide(),
+              actual_segment_size);
+  }
+
+  ASSERT_EQ(expect_segment->nsects, actual_segment->nsects());
+
+  // Make sure that the expected load command is big enough for the number of
+  // sections that it claims to have, and set up a pointer to its first section
+  // structure.
+  ASSERT_EQ(sizeof(*expect_segment) + expect_segment->nsects * sizeof(Section),
+            expect_segment->cmdsize);
+  const Section* expect_sections =
+      reinterpret_cast<const Section*>(&expect_segment[1]);
+
+  for (size_t index = 0; index < actual_segment->nsects(); ++index) {
+    const Section* expect_section = &expect_sections[index];
+    const process_types::section* actual_section =
+        actual_segment->GetSectionAtIndex(index);
+    ExpectSection(&expect_sections[index], actual_section);
+    if (testing::Test::HasFatalFailure()) {
+      return;
+    }
+
+    // Make sure that the section is accessible by GetSectionByName as well.
+    std::string section_name =
+        MachOImageSegmentReader::SectionNameString(expect_section->sectname);
+    const process_types::section* actual_section_by_name =
+        actual_segment->GetSectionByName(section_name);
+    EXPECT_EQ(actual_section, actual_section_by_name);
+
+    // Make sure that the section is accessible by the parent MachOImageReader’s
+    // GetSectionByName.
+    mach_vm_address_t actual_section_address;
+    const process_types::section* actual_section_from_image_by_name =
+        actual_image->GetSectionByName(
+            segment_name, section_name, &actual_section_address);
+    EXPECT_EQ(actual_section, actual_section_from_image_by_name);
+
+    if (actual_segment->SegmentSlides()) {
+      EXPECT_EQ(actual_section_address,
+                actual_section->addr + actual_image->Slide());
+
+      unsigned long expect_section_size;
+      const uint8_t* expect_section_data = getsectiondata(expect_image,
+                                                          segment_name.c_str(),
+                                                          section_name.c_str(),
+                                                          &expect_section_size);
+      mach_vm_address_t expect_section_address =
+          reinterpret_cast<mach_vm_address_t>(expect_section_data);
+      EXPECT_EQ(expect_section_address, actual_section_address);
+      EXPECT_EQ(expect_section_size, actual_section->size);
+    } else {
+      EXPECT_EQ(actual_section_address, actual_section->addr);
+    }
+
+    // Test the parent MachOImageReader’s GetSectionAtIndex as well.
+    mach_vm_address_t actual_section_address_at_index;
+    const process_types::section* actual_section_from_image_at_index =
+        actual_image->GetSectionAtIndex(++(*section_index),
+                                        &actual_section_address_at_index);
+    EXPECT_EQ(actual_section, actual_section_from_image_at_index);
+    EXPECT_EQ(actual_section_address, actual_section_address_at_index);
+  }
+
+  EXPECT_EQ(NULL, actual_segment->GetSectionByName("NoSuchSection"));
+}
+
+// Walks through the load commands of |expect_image|, finding all of the
+// expected segment commands. For each expected segment command, calls
+// actual_image->GetSegmentByName() to obtain an actual segment command, and
+// calls ExpectSegmentCommand() to compare the expected and actual segments. A
+// series of by-name lookups is also performed on the segment to ensure that it
+// behaves correctly when attempting to look up segment and section names that
+// are not present. |test_section_indices| should be true to test
+// MachOImageReader::GetSectionAtIndex() using out-of-range section indices.
+// This should be tested for at least one module, but it’s very noisy in terms
+// of logging output, so this knob is provided to suppress this portion of the
+// test when looping over all modules.
+void ExpectSegmentCommands(const MachHeader* expect_image,
+                           const MachOImageReader* actual_image,
+                           bool test_section_index_bounds) {
+  ASSERT_TRUE(expect_image);
+  ASSERT_TRUE(actual_image);
+
+  const char* commands_base = reinterpret_cast<const char*>(&expect_image[1]);
+  uint32_t position = 0;
+  size_t section_index = 0;
+  for (uint32_t index = 0; index < expect_image->ncmds; ++index) {
+    ASSERT_LT(position, expect_image->sizeofcmds);
+    const load_command* command =
+        reinterpret_cast<const load_command*>(&commands_base[position]);
+    ASSERT_LE(position + command->cmdsize, expect_image->sizeofcmds);
+    if (command->cmd == kSegmentCommand) {
+      const SegmentCommand* expect_segment =
+          reinterpret_cast<const SegmentCommand*>(command);
+      std::string segment_name =
+          MachOImageSegmentReader::SegmentNameString(expect_segment->segname);
+      mach_vm_address_t actual_segment_address;
+      mach_vm_size_t actual_segment_size;
+      const MachOImageSegmentReader* actual_segment =
+          actual_image->GetSegmentByName(
+              segment_name, &actual_segment_address, &actual_segment_size);
+      ExpectSegmentCommand(expect_segment,
+                           expect_image,
+                           actual_segment,
+                           actual_segment_address,
+                           actual_segment_size,
+                           actual_image,
+                           &section_index);
+      if (testing::Test::HasFatalFailure()) {
+        return;
+      }
+    }
+    position += command->cmdsize;
+  }
+  EXPECT_EQ(expect_image->sizeofcmds, position);
+
+  if (test_section_index_bounds) {
+    // GetSectionAtIndex uses a 1-based index. Make sure that the range is
+    // correct.
+    EXPECT_EQ(NULL, actual_image->GetSectionAtIndex(0, NULL));
+    EXPECT_EQ(NULL, actual_image->GetSectionAtIndex(section_index + 1, NULL));
+  }
+
+  // Make sure that by-name lookups for names that don’t exist work properly:
+  // they should return NULL.
+  EXPECT_FALSE(actual_image->GetSegmentByName("NoSuchSegment", NULL, NULL));
+  EXPECT_FALSE(
+      actual_image->GetSectionByName("NoSuchSegment", "NoSuchSection", NULL));
+
+  // Make sure that there’s a __TEXT segment so that this can do a valid test of
+  // a section that doesn’t exist within a segment that does.
+  EXPECT_TRUE(actual_image->GetSegmentByName(SEG_TEXT, NULL, NULL));
+  EXPECT_FALSE(actual_image->GetSectionByName(SEG_TEXT, "NoSuchSection", NULL));
+
+  // Similarly, make sure that a section name that exists in one segment isn’t
+  // accidentally found during a lookup for that section in a different segment.
+  EXPECT_TRUE(actual_image->GetSectionByName(SEG_TEXT, SECT_TEXT, NULL));
+  EXPECT_FALSE(
+      actual_image->GetSectionByName("NoSuchSegment", SECT_TEXT, NULL));
+  EXPECT_FALSE(actual_image->GetSectionByName(SEG_DATA, SECT_TEXT, NULL));
+
+  // The __LINKEDIT segment normally does exist but doesn’t have any sections.
+  EXPECT_FALSE(
+      actual_image->GetSectionByName(SEG_LINKEDIT, "NoSuchSection", NULL));
+  EXPECT_FALSE(actual_image->GetSectionByName(SEG_LINKEDIT, SECT_TEXT, NULL));
+}
+
+// Verifies that |expect_image| is a vaild Mach-O header for the current system
+// by checking its |magic| and |cputype| fields. Then, verifies that the
+// information in |actual_image| matches that in |expect_image|. The |filetype|
+// field is examined, and actual_image->Address() is compared to
+// |expect_image_address|. Various other attributes of |actual_image| are
+// sanity-checked depending on the Mach-O file type. Finally,
+// ExpectSegmentCommands() is called to verify all that all of the segments
+// match; |test_section_index_bounds| is used as an argument to that function.
+void ExpectMachImage(const MachHeader* expect_image,
+                     mach_vm_address_t expect_image_address,
+                     const MachOImageReader* actual_image,
+                     bool test_section_index_bounds) {
+  ASSERT_TRUE(expect_image);
+  ASSERT_TRUE(actual_image);
+
+  EXPECT_EQ(kMachMagic, expect_image->magic);
+  EXPECT_EQ(kCPUType, expect_image->cputype);
+
+  EXPECT_EQ(expect_image->filetype, actual_image->FileType());
+  EXPECT_EQ(expect_image_address, actual_image->Address());
+
+  mach_vm_address_t actual_text_segment_address;
+  mach_vm_size_t actual_text_segment_size;
+  const MachOImageSegmentReader* actual_text_segment =
+      actual_image->GetSegmentByName(
+          SEG_TEXT, &actual_text_segment_address, &actual_text_segment_size);
+  ASSERT_TRUE(actual_text_segment);
+  EXPECT_EQ(expect_image_address, actual_text_segment_address);
+  EXPECT_EQ(actual_image->Size(), actual_text_segment_size);
+  EXPECT_EQ(expect_image_address - actual_text_segment->vmaddr(),
+            actual_image->Slide());
+
+  uint32_t file_type = actual_image->FileType();
+  EXPECT_TRUE(file_type == MH_EXECUTE || file_type == MH_DYLIB ||
+              file_type == MH_DYLINKER || file_type == MH_BUNDLE);
+
+  if (file_type == MH_EXECUTE || file_type == MH_DYLINKER) {
+    EXPECT_EQ("/usr/lib/dyld", actual_image->DylinkerName());
+  }
+
+  // For these, just don’t crash or anything.
+  if (file_type == MH_DYLIB) {
+    actual_image->DylibVersion();
+  }
+  actual_image->SourceVersion();
+  UUID uuid;
+  actual_image->UUID(&uuid);
+
+  ExpectSegmentCommands(expect_image, actual_image, test_section_index_bounds);
+}
+
+TEST(MachOImageReader, Self_MainExecutable) {
+  ProcessReader process_reader;
+  ASSERT_TRUE(process_reader.Initialize(mach_task_self()));
+
+  const MachHeader* mh_execute_header = reinterpret_cast<MachHeader*>(
+      dlsym(RTLD_MAIN_ONLY, "_mh_execute_header"));
+  ASSERT_NE(static_cast<void*>(NULL), mh_execute_header);
+  mach_vm_address_t mh_execute_header_address =
+      reinterpret_cast<mach_vm_address_t>(mh_execute_header);
+
+  MachOImageReader image_reader;
+  ASSERT_TRUE(image_reader.Initialize(
+      &process_reader, mh_execute_header_address, "mh_execute_header"));
+
+  EXPECT_EQ(static_cast<uint32_t>(MH_EXECUTE), image_reader.FileType());
+
+  ExpectMachImage(
+      mh_execute_header, mh_execute_header_address, &image_reader, true);
+}
+
+TEST(MachOImageReader, Self_DyldImages) {
+  ProcessReader process_reader;
+  ASSERT_TRUE(process_reader.Initialize(mach_task_self()));
+
+  const struct dyld_all_image_infos* dyld_image_infos =
+      _dyld_get_all_image_infos();
+  ASSERT_GE(dyld_image_infos->version, 1u);
+  ASSERT_TRUE(dyld_image_infos->infoArray);
+
+  for (uint32_t index = 0; index < dyld_image_infos->infoArrayCount; ++index) {
+    const dyld_image_info* dyld_image = &dyld_image_infos->infoArray[index];
+    SCOPED_TRACE(base::StringPrintf(
+        "index %u, image %s", index, dyld_image->imageFilePath));
+
+    // dyld_image_info::imageLoadAddress is poorly-declared: it’s declared as
+    // const mach_header* in both 32-bit and 64-bit environments, but in the
+    // 64-bit environment, it should be const mach_header_64*.
+    const MachHeader* mach_header =
+        reinterpret_cast<const MachHeader*>(dyld_image->imageLoadAddress);
+    mach_vm_address_t image_address =
+        reinterpret_cast<mach_vm_address_t>(mach_header);
+
+    MachOImageReader image_reader;
+    ASSERT_TRUE(image_reader.Initialize(
+        &process_reader, image_address, dyld_image->imageFilePath));
+
+    uint32_t file_type = image_reader.FileType();
+    if (index == 0) {
+      EXPECT_EQ(static_cast<uint32_t>(MH_EXECUTE), file_type);
+    } else {
+      EXPECT_TRUE(file_type == MH_DYLIB || file_type == MH_BUNDLE);
+    }
+
+    ExpectMachImage(mach_header, image_address, &image_reader, false);
+    if (Test::HasFatalFailure()) {
+      return;
+    }
+  }
+
+  // Now that all of the modules have been verified, make sure that dyld itself
+  // can be read properly too.
+  if (dyld_image_infos->version >= 2) {
+    SCOPED_TRACE("dyld");
+
+    // dyld_all_image_infos::dyldImageLoadAddress is poorly-declared too.
+    const MachHeader* mach_header = reinterpret_cast<const MachHeader*>(
+        dyld_image_infos->dyldImageLoadAddress);
+    mach_vm_address_t image_address =
+        reinterpret_cast<mach_vm_address_t>(mach_header);
+
+    MachOImageReader image_reader;
+    ASSERT_TRUE(
+        image_reader.Initialize(&process_reader, image_address, "dyld"));
+
+    EXPECT_EQ(static_cast<uint32_t>(MH_DYLINKER), image_reader.FileType());
+
+    ExpectMachImage(mach_header, image_address, &image_reader, false);
+    if (Test::HasFatalFailure()) {
+      return;
+    }
+  }
+
+  // If dyld is new enough to record UUIDs, check the UUID of any module that
+  // it says has one. Note that dyld doesn’t record UUIDs of anything that
+  // loaded out of the shared cache, but it should at least have a UUID for the
+  // main executable if it has one.
+  if (dyld_image_infos->version >= 8 && dyld_image_infos->uuidArray) {
+    for (uint32_t index = 0;
+         index < dyld_image_infos->uuidArrayCount;
+         ++index) {
+      const dyld_uuid_info* dyld_image = &dyld_image_infos->uuidArray[index];
+      SCOPED_TRACE(base::StringPrintf("uuid index %u", index));
+
+      // dyld_uuid_info::imageLoadAddress is poorly-declared too.
+      const MachHeader* mach_header =
+          reinterpret_cast<const MachHeader*>(dyld_image->imageLoadAddress);
+      mach_vm_address_t image_address =
+          reinterpret_cast<mach_vm_address_t>(mach_header);
+
+      MachOImageReader image_reader;
+      ASSERT_TRUE(
+          image_reader.Initialize(&process_reader, image_address, "uuid"));
+
+      ExpectMachImage(mach_header, image_address, &image_reader, false);
+
+      UUID expected_uuid;
+      expected_uuid.InitializeFromBytes(dyld_image->imageUUID);
+      UUID actual_uuid;
+      image_reader.UUID(&actual_uuid);
+      EXPECT_EQ(0, memcmp(&actual_uuid, &expected_uuid, sizeof(UUID)));

[Robert Sesek, 2014/09/04 13:18:42]

Might make sense to add UUID::operator==.

+    }
+  }
+}
+
+}  // namespace