// Copyright 2016 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// UserCollectorBase implements common functionality shared by user collectors.
// (e.g. user_collector, arc_collector).

#ifndef CRASH_REPORTER_USER_COLLECTOR_BASE_H_
#define CRASH_REPORTER_USER_COLLECTOR_BASE_H_

#include <string>
#include <vector>

#include <base/files/file_path.h>
#include <base/optional.h>
#include <base/time/time.h>

#include "crash-reporter/crash_collector.h"

class UserCollectorBase : public CrashCollector {
 public:
  UserCollectorBase(
      const std::string& collector_name,
      CrashDirectorySelectionMethod crash_directory_selection_method);

  void Initialize(bool directory_failure, bool early);

  struct CrashAttributes {
    pid_t pid;
    int signal;
    uid_t uid;
    gid_t gid;
    std::string exec_name;
  };

  // Handle a specific user crash.  Returns true on success.
  bool HandleCrash(const CrashAttributes& crash_attributes,
                   const char* force_exec);

  // Attempt to parse a given attributes string into a CrashAttributes struct.
  // The attributes string is generated in the kernel by the core_pattern
  // specification %P:%s:%u:%g:%f, and consists of the pid, the signal
  // responsible for terminating the process, the uid, the gid, and the
  // executable's name, separated by colons.
  // For example, an input string 123456:11:1000:2000:foobar is pid
  // 123456, signal 11, uid 1000, gid 2000, and exec name "foobar".
  // See man 5 core for details on the format.
  static base::Optional<CrashAttributes> ParseCrashAttributes(
      const std::string& crash_attributes);

 protected:
  // Enumeration to pass to GetIdFromStatus.  Must match the order
  // that the kernel lists IDs in the status file.
  enum IdKind : int {
    kIdReal = 0,        // uid and gid
    kIdEffective = 1,   // euid and egid
    kIdSet = 2,         // suid and sgid
    kIdFileSystem = 3,  // fsuid and fsgid
    kIdMax
  };

  bool ShouldDump(base::Optional<pid_t> pid, std::string* reason) const;

  bool ShouldDump(std::string* reason) const;

  // Returns, via |line|, the first line in |lines| that starts with |prefix|.
  // Returns true if a line is found, or false otherwise.
  bool GetFirstLineWithPrefix(const std::vector<std::string>& lines,
                              const char* prefix,
                              std::string* line);

  // Returns the identifier of |kind|, via |id|, found in |status_lines| on
  // the line starting with |prefix|. |status_lines| contains the lines in
  // the status file. Returns true if the identifier can be determined.
  bool GetIdFromStatus(const char* prefix,
                       IdKind kind,
                       const std::vector<std::string>& status_lines,
                       int* id);

  // Returns the process state, via |state|, found in |status_lines|, which
  // contains the lines in the status file. Returns true if the process state
  // can be determined.
  bool GetStateFromStatus(const std::vector<std::string>& status_lines,
                          std::string* state);

  bool ClobberContainerDirectory(const base::FilePath& container_dir);

  // Returns the command and arguments for process |pid|. Returns an empty list
  // on failure or if the process is a zombie. Virtual for testing.
  virtual std::vector<std::string> GetCommandLine(pid_t pid) const;

  // Path under which all temporary crash processing occurs.
  const base::FilePath GetCrashProcessingDir();

  bool initialized_ = false;

  static const char* kUserId;
  static const char* kGroupId;

 private:
  // Send DBus message announcing the crash. Virtual so that we can mock out
  // during unit tests.
  virtual void AccounceUserCrash();

  virtual bool ShouldDump(pid_t pid,
                          uid_t uid,
                          const std::string& exec,
                          std::string* reason) = 0;

  virtual ErrorType ConvertCoreToMinidump(
      pid_t pid,
      const base::FilePath& container_dir,
      const base::FilePath& core_path,
      const base::FilePath& minidump_path) = 0;

  // Adds additional metadata for a crash of executable |exec| with |pid|.
  virtual void AddExtraMetadata(const std::string& exec, pid_t pid) {}

  ErrorType ConvertAndEnqueueCrash(pid_t pid,
                                   const std::string& exec,
                                   uid_t supplied_ruid,
                                   gid_t supplied_rgid,
                                   const base::TimeDelta& crash_time,
                                   bool* out_of_capacity);

  // Determines the crash directory for given pid based on pid's owner,
  // and creates the directory if necessary with appropriate permissions.
  // Returns true whether or not directory needed to be created, false on
  // any failure.
  bool GetCreatedCrashDirectory(pid_t pid,
                                uid_t supplied_ruid,
                                base::FilePath* crash_file_path,
                                bool* out_of_capacity);

  bool directory_failure_ = false;
};

#endif  // CRASH_REPORTER_USER_COLLECTOR_BASE_H_