thread.go

Documentation: github.com/prometheus/procfs

     1  // Copyright 2022 The Prometheus Authors
     2  // Licensed under the Apache License, Version 2.0 (the "License");
     3  // you may not use this file except in compliance with the License.
     4  // You may obtain a copy of the License at
     5  //
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package procfs
    15  
    16  import (
    17  	"fmt"
    18  	"os"
    19  	"strconv"
    20  
    21  	fsi "github.com/prometheus/procfs/internal/fs"
    22  )
    23  
    24  // Provide access to /proc/PID/task/TID files, for thread specific values. Since
    25  // such files have the same structure as /proc/PID/ ones, the data structures
    26  // and the parsers for the latter may be reused.
    27  
    28  // AllThreads returns a list of all currently available threads under /proc/PID.
    29  func AllThreads(pid int) (Procs, error) {
    30  	fs, err := NewFS(DefaultMountPoint)
    31  	if err != nil {
    32  		return Procs{}, err
    33  	}
    34  	return fs.AllThreads(pid)
    35  }
    36  
    37  // AllThreads returns a list of all currently available threads for PID.
    38  func (fs FS) AllThreads(pid int) (Procs, error) {
    39  	taskPath := fs.proc.Path(strconv.Itoa(pid), "task")
    40  	d, err := os.Open(taskPath)
    41  	if err != nil {
    42  		return Procs{}, err
    43  	}
    44  	defer d.Close()
    45  
    46  	names, err := d.Readdirnames(-1)
    47  	if err != nil {
    48  		return Procs{}, fmt.Errorf("%s: could not read %q: %w", ErrFileRead, d.Name(), err)
    49  	}
    50  
    51  	t := Procs{}
    52  	for _, n := range names {
    53  		tid, err := strconv.ParseInt(n, 10, 64)
    54  		if err != nil {
    55  			continue
    56  		}
    57  
    58  		t = append(t, Proc{PID: int(tid), fs: FS{fsi.FS(taskPath), fs.isReal}})
    59  	}
    60  
    61  	return t, nil
    62  }
    63  
    64  // Thread returns a process for a given PID, TID.
    65  func (fs FS) Thread(pid, tid int) (Proc, error) {
    66  	taskPath := fs.proc.Path(strconv.Itoa(pid), "task")
    67  	if _, err := os.Stat(taskPath); err != nil {
    68  		return Proc{}, err
    69  	}
    70  	return Proc{PID: tid, fs: FS{fsi.FS(taskPath), fs.isReal}}, nil
    71  }
    72  
    73  // Thread returns a process for a given TID of Proc.
    74  func (proc Proc) Thread(tid int) (Proc, error) {
    75  	tfs := FS{fsi.FS(proc.path("task")), proc.fs.isReal}
    76  	if _, err := os.Stat(tfs.proc.Path(strconv.Itoa(tid))); err != nil {
    77  		return Proc{}, err
    78  	}
    79  	return Proc{PID: tid, fs: tfs}, nil
    80  }
    81
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