syscalls_linux.go

Documentation: runtime/testdata/testprog

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"internal/testenv"
    11  	"os"
    12  	"syscall"
    13  )
    14  
    15  func gettid() int {
    16  	return syscall.Gettid()
    17  }
    18  
    19  func tidExists(tid int) (exists, supported bool) {
    20  	stat, err := os.ReadFile(fmt.Sprintf("/proc/self/task/%d/stat", tid))
    21  	if os.IsNotExist(err) {
    22  		return false, true
    23  	}
    24  	// Check if it's a zombie thread.
    25  	state := bytes.Fields(stat)[2]
    26  	return !(len(state) == 1 && state[0] == 'Z'), true
    27  }
    28  
    29  func getcwd() (string, error) {
    30  	if !syscall.ImplementsGetwd {
    31  		return "", nil
    32  	}
    33  	// Use the syscall to get the current working directory.
    34  	// This is imperative for checking for OS thread state
    35  	// after an unshare since os.Getwd might just check the
    36  	// environment, or use some other mechanism.
    37  	var buf [4096]byte
    38  	n, err := syscall.Getcwd(buf[:])
    39  	if err != nil {
    40  		return "", err
    41  	}
    42  	// Subtract one for null terminator.
    43  	return string(buf[:n-1]), nil
    44  }
    45  
    46  func unshareFs() error {
    47  	err := syscall.Unshare(syscall.CLONE_FS)
    48  	if testenv.SyscallIsNotSupported(err) {
    49  		return errNotPermitted
    50  	}
    51  	return err
    52  }
    53  
    54  func chdir(path string) error {
    55  	return syscall.Chdir(path)
    56  }
    57
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