Files
nomad/vendor/github.com/prometheus/procfs/internal/util/sysreadfile.go
Seth Hoenig 15fb4c990a deps: Switch to Go modules for dependency management
This PR switches the Nomad repository from using govendor to Go modules
for managing dependencies. Aspects of the Nomad workflow remain pretty
much the same. The usual Makefile targets should continue to work as
they always did. The API submodule simply defers to the parent Nomad
version on the repository, keeping the semantics of API versioning that
currently exists.
2020-06-02 14:30:36 -05:00

49 lines
1.4 KiB
Go

// Copyright 2018 The Prometheus Authors
// 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.
// +build linux,!appengine
package util
import (
"bytes"
"os"
"syscall"
)
// SysReadFile is a simplified ioutil.ReadFile that invokes syscall.Read directly.
// https://github.com/prometheus/node_exporter/pull/728/files
//
// Note that this function will not read files larger than 128 bytes.
func SysReadFile(file string) (string, error) {
f, err := os.Open(file)
if err != nil {
return "", err
}
defer f.Close()
// On some machines, hwmon drivers are broken and return EAGAIN. This causes
// Go's ioutil.ReadFile implementation to poll forever.
//
// Since we either want to read data or bail immediately, do the simplest
// possible read using syscall directly.
const sysFileBufferSize = 128
b := make([]byte, sysFileBufferSize)
n, err := syscall.Read(int(f.Fd()), b)
if err != nil {
return "", err
}
return string(bytes.TrimSpace(b[:n])), nil
}