Create snapshot/mac and move some files from snapshot and util to there

util/mac/mach_o_image_segment_reader.h

-// 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.
-
-#ifndef CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SEGMENT_READER_H_
-#define CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SEGMENT_READER_H_
-
-#include <mach/mach.h>
-#include <stdint.h>
-#include <sys/types.h>
-
-#include <map>
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "util/mac/process_types.h"
-#include "util/misc/initialization_state_dcheck.h"
-
-namespace crashpad {
-
-//! \brief A reader for `LC_SEGMENT` or `LC_SEGMENT_64` load commands in Mach-O
-//!     images mapped into another process.
-//!
-//! This class is capable of reading both `LC_SEGMENT` and `LC_SEGMENT_64` based
-//! on the bitness of the remote process.
-//!
-//! A MachOImageSegmentReader will normally be instantiated by a
-//! MachOImageReader.
-class MachOImageSegmentReader {
- public:
-  MachOImageSegmentReader();
-  ~MachOImageSegmentReader();
-
-  //! \brief Reads the segment load command from another process.
-  //!
-  //! This method must only be called once on an object. This method must be
-  //! called successfully before any other method in this class may be called.
-  //!
-  //! \param[in] process_reader The reader for the remote process.
-  //! \param[in] load_command_address The address, in the remote process’
-  //!     address space, where the `LC_SEGMENT` or `LC_SEGMENT_64` load command
-  //!     to be read is located. This address is determined by a Mach-O image
-  //!     reader, such as MachOImageReader, as it walks Mach-O load commands.
-  //! \param[in] load_command_info A string to be used in logged messages. This
-  //!     string is for diagnostic purposes only, and may be empty.
-  //!
-  //! \return `true` if the load command was read successfully. `false`
-  //!     otherwise, with an appropriate message logged.
-  bool Initialize(ProcessReader* process_reader,
-                  mach_vm_address_t load_command_address,
-                  const std::string& load_command_info);
-
-  //! \brief Sets the image’s slide value.
-  //!
-  //! This method must only be called once on an object, after Initialize() is
-  //! called successfully. It must be called before Address(), Size(),
-  //! GetSectionByName(), or GetSectionAtIndex() can be called.
-  //!
-  //! This method is provided because slide is a property of the image that
-  //! cannot be determined until at least some segments have been read. As such,
-  //! it is not necessarily known at the time that Initialize() is called.
-  void SetSlide(mach_vm_size_t slide);
-
-  //! \brief Returns the segment’s name.
-  //!
-  //! The segment’s name is taken from the load command’s `segname` field.
-  //! Common segment names are `"__TEXT"`, `"__DATA"`, and `"__LINKEDIT"`.
-  //! Symbolic constants for these common names are defined in
-  //! `<mach-o/loader.h>`.
-  std::string Name() const;
-
-  //! \return The segment’s actual load address in memory, adjusted for any
-  //!     “slide”.
-  //!
-  //! \note For the segment’s preferred load address, not adjusted for slide,
-  //!     use vmaddr().
-  mach_vm_address_t Address() const;
-
-  //! \return The segment’s actual size address in memory, adjusted for any
-  //!     growth in the case of a nonsliding segment.
-  //!
-  //! \note For the segment’s preferred size, not adjusted for growth, use
-  //!     vmsize().
-  mach_vm_address_t Size() const;
-
-  //! \brief The segment’s preferred load address.
-  //!
-  //! \return The segment’s preferred load address as stored in the Mach-O file.
-  //!
-  //! \note This value is not adjusted for any “slide” that may have occurred
-  //!     when the image was loaded. Use Address() for a value adjusted for
-  //!     slide.
-  //!
-  //! \sa MachOImageReader::GetSegmentByName()
-  mach_vm_address_t vmaddr() const { return segment_command_.vmaddr; }
-
-  //! \brief Returns the segment’s size as mapped into memory.
-  //!
-  //! \note For non-sliding segments, this value is not adjusted for any growth
-  //!     that may have occurred when the image was loaded. Use Size() for a
-  //!     value adjusted for growth.
-  mach_vm_size_t vmsize() const { return segment_command_.vmsize; }
-
-  //! \brief Returns the file offset of the mapped segment in the file from
-  //!     which it was mapped.
-  //!
-  //! The file offset is the difference between the beginning of the
-  //! `mach_header` or `mach_header_64` and the beginning of the segment’s
-  //! mapped region. For segments that are not mapped from a file (such as
-  //! `__PAGEZERO` segments), this will be `0`.
-  mach_vm_size_t fileoff() const { return segment_command_.fileoff; }
-
-  //! \brief Returns the number of sections in the segment.
-  //!
-  //! This will return `0` for a segment without any sections, typical for
-  //! `__PAGEZERO` and `__LINKEDIT` segments.
-  //!
-  //! Although the Mach-O file format uses a `uint32_t` for this field, there is
-  //! an overall limit of 255 sections in an entire Mach-O image file (not just
-  //! in a single segment) imposed by the symbol table format. Symbols will not
-  //! be able to reference anything in a section beyond the first 255 in a
-  //! Mach-O image file.
-  uint32_t nsects() const { return segment_command_.nsects; }
-
-  //! \brief Obtain section information by section name.
-  //!
-  //! \param[in] section_name The name of the section to search for, without the
-  //!     leading segment name. For example, use `"__text"`, not
-  //!     `"__TEXT,__text"` or `"__TEXT.__text"`.
-  //! \param[out] address The actual address that the section was loaded at in
-  //!     memory, taking any “slide” into account if the section did not load at
-  //!     its preferred address as stored in the Mach-O image file. This
-  //!     parameter can be `nullptr`.
-  //!
-  //! \return A pointer to the section information if it was found, or `nullptr`
-  //!     if it was not found. The caller does not take ownership; the lifetime
-  //!     of the returned object is scoped to the lifetime of this
-  //!     MachOImageSegmentReader object.
-  //!
-  //! \note The process_types::section::addr field gives the section’s preferred
-  //!     load address as stored in the Mach-O image file, and is not adjusted
-  //!     for any “slide” that may have occurred when the image was loaded.
-  //!
-  //! \sa MachOImageReader::GetSectionByName()
-  const process_types::section* GetSectionByName(
-      const std::string& section_name,
-      mach_vm_address_t* address) const;
-
-  //! \brief Obtain section information by section index.
-  //!
-  //! \param[in] index The index of the section to return, in the order that it
-  //!     appears in the segment load command. Unlike
-  //!     MachOImageReader::GetSectionAtIndex(), this is a 0-based index. This
-  //!     parameter must be in the range of valid indices aas reported by
-  //!     nsects().
-  //! \param[out] address The actual address that the section was loaded at in
-  //!     memory, taking any “slide” into account if the section did not load at
-  //!     its preferred address as stored in the Mach-O image file. This
-  //!     parameter can be `nullptr`.
-  //!
-  //! \return A pointer to the section information. If \a index is out of range,
-  //!     execution is aborted.  The caller does not take ownership; the
-  //!     lifetime of the returned object is scoped to the lifetime of this
-  //!     MachOImageSegmentReader object.
-  //!
-  //! \note The process_types::section::addr field gives the section’s preferred
-  //!     load address as stored in the Mach-O image file, and is not adjusted
-  //!     for any “slide” that may have occurred when the image was loaded.
-  //! \note Unlike MachOImageReader::GetSectionAtIndex(), this method does not
-  //!     accept out-of-range values for \a index, and aborts execution instead
-  //!     of returning `nullptr` upon encountering an out-of-range value. This
-  //!     is because this method is expected to be used in a loop that can be
-  //!     limited to nsects() iterations, so an out-of-range error can be
-  //!     treated more harshly as a logic error, as opposed to a data error.
-  //!
-  //! \sa MachOImageReader::GetSectionAtIndex()
-  const process_types::section* GetSectionAtIndex(
-      size_t index,
-      mach_vm_address_t* address) const;
-
-  //! Returns whether the segment slides.
-  //!
-  //! Most segments slide, but the `__PAGEZERO` segment does not, it grows
-  //! instead. This method identifies non-sliding segments in the same way that
-  //! the kernel does.
-  bool SegmentSlides() const;
-
-  //! \brief Returns a segment name string.
-  //!
-  //! Segment names may be 16 characters long, and are not necessarily
-  //! `NUL`-terminated. This function will return a segment name based on up to
-  //! the first 16 characters found at \a segment_name_c.
-  static std::string SegmentNameString(const char* segment_name_c);
-
-  //! \brief Returns a section name string.
-  //!
-  //! Section names may be 16 characters long, and are not necessarily
-  //! `NUL`-terminated. This function will return a section name based on up to
-  //! the first 16 characters found at \a section_name_c.
-  static std::string SectionNameString(const char* section_name_c);
-
-  //! \brief Returns a segment and section name string.
-  //!
-  //! A segment and section name string is composed of a segment name string
-  //! (see SegmentNameString()) and a section name string (see
-  //! SectionNameString()) separated by a comma. An example is
-  //! `"__TEXT,__text"`.
-  static std::string SegmentAndSectionNameString(const char* segment_name_c,
-                                                 const char* section_name_c);
-
- private:
-  //! \brief The internal implementation of Name().
-  //!
-  //! This is identical to Name() but does not perform the
-  //! InitializationStateDcheck check. It may be called during initialization
-  //! provided that the caller only does so after segment_command_ has been
-  //! read successfully.
-  std::string NameInternal() const;
-
-  // The segment command data read from the remote process.
-  process_types::segment_command segment_command_;
-
-  // Section structures read from the remote process in the order that they are
-  // given in the remote process.
-  std::vector<process_types::section> sections_;
-
-  // Maps section names to indices into the sections_ vector.
-  std::map<std::string, size_t> section_map_;
-
-  // The image’s slide. Note that the segment’s slide may be 0 and not the value
-  // of the image’s slide if SegmentSlides() is false. In that case, the
-  // segment is extended instead of slid, so its size as loaded will be
-  // increased by this value.
-  mach_vm_size_t slide_;
-
-  InitializationStateDcheck initialized_;
-  InitializationStateDcheck initialized_slide_;
-
-  DISALLOW_COPY_AND_ASSIGN(MachOImageSegmentReader);
-};
-
-}  // namespace crashpad
-
-#endif  // CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SEGMENT_READER_H_