breakpad/src/client/linux/handler/minidump_descriptor.h

// Copyright 2012 Google LLC
//
// 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.
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
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#ifndef CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_
#define CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_

#include <assert.h>
#include <sys/types.h>

#include <cstdint>
#include <string>

#include "client/linux/handler/microdump_extra_info.h"
#include "common/using_std_string.h"

// This class describes how a crash dump should be generated, either:
// - Writing a full minidump to a file in a given directory (the actual path,
//   inside the directory, is determined by this class).
// - Writing a full minidump to a given fd.
// - Writing a reduced microdump to the console (logcat on Android).
namespace google_breakpad {

class MinidumpDescriptor {
 public:
  struct MicrodumpOnConsole {};
  static const MicrodumpOnConsole kMicrodumpOnConsole;

  MinidumpDescriptor()
      : mode_(kUninitialized),
        fd_(-1),
        size_limit_(-1),
        address_within_principal_mapping_(0),
        skip_dump_if_principal_mapping_not_referenced_(false) {}

  explicit MinidumpDescriptor(const string& directory)
      : mode_(kWriteMinidumpToFile),
        fd_(-1),
        directory_(directory),
        c_path_(NULL),
        size_limit_(-1),
        address_within_principal_mapping_(0),
        skip_dump_if_principal_mapping_not_referenced_(false),
        sanitize_stacks_(false) {
    assert(!directory.empty());
  }

  explicit MinidumpDescriptor(int fd)
      : mode_(kWriteMinidumpToFd),
        fd_(fd),
        c_path_(NULL),
        size_limit_(-1),
        address_within_principal_mapping_(0),
        skip_dump_if_principal_mapping_not_referenced_(false),
        sanitize_stacks_(false) {
    assert(fd != -1);
  }

  explicit MinidumpDescriptor(const MicrodumpOnConsole&)
      : mode_(kWriteMicrodumpToConsole),
        fd_(-1),
        size_limit_(-1),
        address_within_principal_mapping_(0),
        skip_dump_if_principal_mapping_not_referenced_(false),
        sanitize_stacks_(false) {}

  explicit MinidumpDescriptor(const MinidumpDescriptor& descriptor);
  MinidumpDescriptor& operator=(const MinidumpDescriptor& descriptor);

  static MinidumpDescriptor getMicrodumpDescriptor();

  bool IsFD() const { return mode_ == kWriteMinidumpToFd; }

  int fd() const { return fd_; }

  string directory() const { return directory_; }

  const char* path() const { return c_path_; }

  bool IsMicrodumpOnConsole() const {
    return mode_ == kWriteMicrodumpToConsole;
  }

  // Updates the path so it is unique.
  // Should be called from a normal context: this methods uses the heap.
  void UpdatePath();

  off_t size_limit() const { return size_limit_; }
  void set_size_limit(off_t limit) { size_limit_ = limit; }

  uintptr_t address_within_principal_mapping() const {
    return address_within_principal_mapping_;
  }
  void set_address_within_principal_mapping(
      uintptr_t address_within_principal_mapping) {
    address_within_principal_mapping_ = address_within_principal_mapping;
  }

  bool skip_dump_if_principal_mapping_not_referenced() {
    return skip_dump_if_principal_mapping_not_referenced_;
  }
  void set_skip_dump_if_principal_mapping_not_referenced(
      bool skip_dump_if_principal_mapping_not_referenced) {
    skip_dump_if_principal_mapping_not_referenced_ =
        skip_dump_if_principal_mapping_not_referenced;
  }

  bool sanitize_stacks() const { return sanitize_stacks_; }
  void set_sanitize_stacks(bool sanitize_stacks) {
    sanitize_stacks_ = sanitize_stacks;
  }

  MicrodumpExtraInfo* microdump_extra_info() {
    assert(IsMicrodumpOnConsole());
    return &microdump_extra_info_;
  }

 private:
  enum DumpMode {
    kUninitialized = 0,
    kWriteMinidumpToFile,
    kWriteMinidumpToFd,
    kWriteMicrodumpToConsole
  };

  // Specifies the dump mode (see DumpMode).
  DumpMode mode_;

  // The file descriptor where the minidump is generated.
  int fd_;

  // The directory where the minidump should be generated.
  string directory_;

  // The full path to the generated minidump.
  string path_;

  // The C string of |path_|. Precomputed so it can be access from a compromised
  // context.
  const char* c_path_;

  off_t size_limit_;

  // This member points somewhere into the main module for this
  // process (the module that is considerered interesting for the
  // purposes of debugging crashes).
  uintptr_t address_within_principal_mapping_;

  // If set, threads that do not reference the address range
  // associated with |address_within_principal_mapping_| will not have their
  // stacks logged.
  bool skip_dump_if_principal_mapping_not_referenced_;

  // If set, stacks are sanitized to remove PII. This involves
  // overwriting any pointer-aligned words that are not either
  // pointers into a process mapping or small integers (+/-4096). This
  // leaves enough information to unwind stacks, and preserve some
  // register values, but elides strings and other program data.
  bool sanitize_stacks_;

  // The extra microdump data (e.g. product name/version, build
  // fingerprint, gpu fingerprint) that should be appended to the dump
  // (microdump only). Microdumps don't have the ability of appending
  // extra metadata after the dump is generated (as opposite to
  // minidumps MIME fields), therefore the extra data must be provided
  // upfront. Any memory pointed to by members of the
  // MicrodumpExtraInfo struct must be valid for the lifetime of the
  // process (read: the caller has to guarantee that it is stored in
  // global static storage.)
  MicrodumpExtraInfo microdump_extra_info_;
};

}  // namespace google_breakpad

#endif  // CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_