| // Copyright 2019 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. |
| |
| package util |
| |
| import ( |
| "io" |
| "io/ioutil" |
| "os" |
| ) |
| |
| // ReadFileNoStat uses ioutil.ReadAll to read contents of entire file. |
| // This is similar to ioutil.ReadFile but without the call to os.Stat, because |
| // many files in /proc and /sys report incorrect file sizes (either 0 or 4096). |
| // Reads a max file size of 512kB. For files larger than this, a scanner |
| // should be used. |
| func ReadFileNoStat(filename string) ([]byte, error) { |
| const maxBufferSize = 1024 * 512 |
| |
| f, err := os.Open(filename) |
| if err != nil { |
| return nil, err |
| } |
| defer f.Close() |
| |
| reader := io.LimitReader(f, maxBufferSize) |
| return ioutil.ReadAll(reader) |
| } |