/usr/share/gocode/src/github.com/jacobsa/fuse/mount_linux.go is in golang-github-jacobsa-fuse-dev 0.0~git20150806.0.9a7512a-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | package fuse
import (
"bufio"
"fmt"
"io"
"log"
"net"
"os"
"os/exec"
"sync"
"syscall"
)
func lineLogger(wg *sync.WaitGroup, prefix string, r io.ReadCloser) {
defer wg.Done()
scanner := bufio.NewScanner(r)
for scanner.Scan() {
switch line := scanner.Text(); line {
case `fusermount: failed to open /etc/fuse.conf: Permission denied`:
// Silence this particular message, it occurs way too
// commonly and isn't very relevant to whether the mount
// succeeds or not.
continue
default:
log.Printf("%s: %s", prefix, line)
}
}
if err := scanner.Err(); err != nil {
log.Printf("%s, error reading: %v", prefix, err)
}
}
// Begin the process of mounting at the given directory, returning a connection
// to the kernel. Mounting continues in the background, and is complete when an
// error is written to the supplied channel. The file system may need to
// service the connection in order for mounting to complete.
func mount(
dir string,
cfg *MountConfig,
ready chan<- error) (dev *os.File, err error) {
// On linux, mounting is never delayed.
ready <- nil
// Create a socket pair.
fds, err := syscall.Socketpair(syscall.AF_FILE, syscall.SOCK_STREAM, 0)
if err != nil {
err = fmt.Errorf("Socketpair: %v", err)
return
}
// Wrap the sockets into os.File objects that we will pass off to fusermount.
writeFile := os.NewFile(uintptr(fds[0]), "fusermount-child-writes")
defer writeFile.Close()
readFile := os.NewFile(uintptr(fds[1]), "fusermount-parent-reads")
defer readFile.Close()
// Start fusermount, passing it pipes for stdout and stderr.
cmd := exec.Command(
"fusermount",
"-o", cfg.toOptionsString(),
"--",
dir,
)
cmd.Env = append(os.Environ(), "_FUSE_COMMFD=3")
cmd.ExtraFiles = []*os.File{writeFile}
stdout, err := cmd.StdoutPipe()
if err != nil {
err = fmt.Errorf("StdoutPipe: %v", err)
return
}
stderr, err := cmd.StderrPipe()
if err != nil {
err = fmt.Errorf("StderrPipe: %v", err)
return
}
err = cmd.Start()
if err != nil {
err = fmt.Errorf("Starting fusermount: %v", err)
return
}
// Log fusermount output until it closes stdout and stderr.
var wg sync.WaitGroup
wg.Add(2)
go lineLogger(&wg, "mount helper output", stdout)
go lineLogger(&wg, "mount helper error", stderr)
wg.Wait()
// Wait for the command.
err = cmd.Wait()
if err != nil {
err = fmt.Errorf("fusermount: %v", err)
return
}
// Wrap the socket file in a connection.
c, err := net.FileConn(readFile)
if err != nil {
err = fmt.Errorf("FileConn: %v", err)
return
}
defer c.Close()
// We expect to have a Unix domain socket.
uc, ok := c.(*net.UnixConn)
if !ok {
err = fmt.Errorf("Expected UnixConn, got %T", c)
return
}
// Read a message.
buf := make([]byte, 32) // expect 1 byte
oob := make([]byte, 32) // expect 24 bytes
_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
if err != nil {
err = fmt.Errorf("ReadMsgUnix: %v", err)
return
}
// Parse the message.
scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
if err != nil {
err = fmt.Errorf("ParseSocketControlMessage: %v", err)
return
}
// We expect one message.
if len(scms) != 1 {
err = fmt.Errorf("expected 1 SocketControlMessage; got scms = %#v", scms)
return
}
scm := scms[0]
// Pull out the FD returned by fusermount
gotFds, err := syscall.ParseUnixRights(&scm)
if err != nil {
err = fmt.Errorf("syscall.ParseUnixRights: %v", err)
return
}
if len(gotFds) != 1 {
err = fmt.Errorf("wanted 1 fd; got %#v", gotFds)
return
}
// Turn the FD into an os.File.
dev = os.NewFile(uintptr(gotFds[0]), "/dev/fuse")
return
}
|