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Commit 13b1f342 authored by Tom Cherry's avatar Tom Cherry
Browse files

Add android::base::GetPids() function to return all pids 

We loop over /proc to iterate through pids in a lot of code, so let's
consolidate this into a single function in libbase.

Test: new unit test
Change-Id: I908fab90b603546d0e3e8b8acdc8dadfc3552d62
parent 52f61717

base/Android.bp

+2 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ cc_defaults { 
        "logging.cpp",

        "mapped_file.cpp",

        "parsenetaddress.cpp",

        "process.cpp",

        "properties.cpp",

        "quick_exit.cpp",

        "stringprintf.cpp",
@@ -145,6 +146,7 @@ cc_test { 
        "parsedouble_test.cpp",

        "parseint_test.cpp",

        "parsenetaddress_test.cpp",

        "process_test.cpp",

        "properties_test.cpp",

        "quick_exit_test.cpp",

        "result_test.cpp",

base/include/android-base/process.h

0 → 100644
+60 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2019 The Android Open Source Project

 *

 * 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.

 */



#pragma once



#include <dirent.h>

#include <sys/types.h>



#include <iterator>

#include <memory>

#include <vector>



namespace android {

namespace base {



class AllPids {

  class PidIterator {

   public:

    PidIterator(DIR* dir) : dir_(dir, closedir) { Increment(); }

    PidIterator& operator++() {

      Increment();

      return *this;

    }

    bool operator==(const PidIterator& other) const { return pid_ == other.pid_; }

    bool operator!=(const PidIterator& other) const { return !(*this == other); }

    long operator*() const { return pid_; }

    // iterator traits

    using difference_type = pid_t;

    using value_type = pid_t;

    using pointer = const pid_t*;

    using reference = const pid_t&;

    using iterator_category = std::input_iterator_tag;



   private:

    void Increment();



    pid_t pid_ = -1;

    std::unique_ptr<DIR, decltype(&closedir)> dir_;

  };



 public:

  PidIterator begin() { return opendir("/proc"); }

  PidIterator end() { return nullptr; }

};



}  // namespace base

}  // namespace android

base/process.cpp

0 → 100644
+39 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2019 The Android Open Source Project

 *

 * 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 "android-base/process.h"



namespace android {

namespace base {



void AllPids::PidIterator::Increment() {

  if (!dir_) {

    return;

  }



  dirent* de;

  while ((de = readdir(dir_.get())) != nullptr) {

    pid_t pid = atoi(de->d_name);

    if (pid != 0) {

      pid_ = pid;

      return;

    }

  }

  pid_ = -1;

}



}  // namespace base

}  // namespace android

base/process_test.cpp

0 → 100644
+35 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2019 The Android Open Source Project

 *

 * 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 "android-base/process.h"



#include <unistd.h>



#include <gtest/gtest.h>



TEST(process, find_ourselves) {

#if defined(__linux__)

  bool found_our_pid = false;

  for (const auto& pid : android::base::AllPids{}) {

    if (pid == getpid()) {

      found_our_pid = true;

    }

  }



  EXPECT_TRUE(found_our_pid);



#endif

}