go.etcd.io/etcd@v3.3.27+incompatible/pkg/runtime/fds_linux.go (about)

     1  // Copyright 2015 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package runtime implements utility functions for runtime systems.
    16  package runtime
    17  
    18  import (
    19  	"os"
    20  	"syscall"
    21  )
    22  
    23  func FDLimit() (uint64, error) {
    24  	var rlimit syscall.Rlimit
    25  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlimit); err != nil {
    26  		return 0, err
    27  	}
    28  	return rlimit.Cur, nil
    29  }
    30  
    31  func FDUsage() (uint64, error) {
    32  	return countFiles("/proc/self/fd")
    33  }
    34  
    35  // countFiles reads the directory named by dirname and returns the count.
    36  // This is same as stdlib "io/ioutil.ReadDir" but without sorting.
    37  func countFiles(dirname string) (uint64, error) {
    38  	f, err := os.Open(dirname)
    39  	if err != nil {
    40  		return 0, err
    41  	}
    42  	list, err := f.Readdir(-1)
    43  	f.Close()
    44  	if err != nil {
    45  		return 0, err
    46  	}
    47  	return uint64(len(list)), nil
    48  }