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|
package file
import (
"bufio"
"bytes"
"fmt"
"os"
"strconv"
"strings"
)
type File interface {
String() string
Name() string
FlagsString() string
}
type FdFile struct {
fd int32
name string
Flags *int32 // TODO: This must be a pointer as via dup(2) - means, we need to synchronise access as well .. use atomicint
flagsFromFdInfo bool
}
func NewFd(fd int32, name []byte, flags int32) FdFile {
return FdFile{
fd: fd,
name: stringValue(name),
Flags: &flags,
}
}
func NewFdWithPid(fd int32, pid uint32) FdFile {
linkName, err := os.Readlink(fmt.Sprintf("/proc/%d/fd/%d", pid, fd))
if err != nil {
fmt.Println("DEBUG", err)
var unknownFlags int32 = -1
return FdFile{
fd: fd,
name: "?",
Flags: &unknownFlags, // Unknown flags at this point
flagsFromFdInfo: true,
}
}
flags, _ := readFlagsFromFdInfo(fd, pid)
return FdFile{
fd: fd,
name: linkName,
Flags: &flags,
flagsFromFdInfo: true,
}
}
func (f FdFile) Dup(fd int32) FdFile {
duppedFd := f
duppedFd.fd = fd
duppedFd.flagsFromFdInfo = false
return duppedFd
}
func readFlagsFromFdInfo(fd int32, pid uint32) (int32, error) {
data, err := os.ReadFile(fmt.Sprintf("/proc/%d/fdinfo/%d", pid, fd))
if err != nil {
return -1, err
}
scanner := bufio.NewScanner(bytes.NewReader(data))
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "flags:") {
flagsStr := strings.Fields(line)[1]
flags, err := strconv.ParseUint(flagsStr, 8, 32)
return int32(flags), err
}
}
return -1, scanner.Err()
}
func (f FdFile) Name() string {
return f.name
}
func (f FdFile) FlagsString() string {
var flags int32 = -1
if f.Flags != nil {
flags = *f.Flags
}
return flagsToStr(flags)
}
func (f FdFile) String() string {
var sb strings.Builder
if len(f.name) == 0 {
sb.WriteString("?")
} else {
sb.WriteString(f.name)
sb.WriteString(" (")
sb.WriteString(strconv.FormatInt(int64(f.fd), 10))
sb.WriteString(",")
sb.WriteString(f.FlagsString())
sb.WriteString(")")
if f.flagsFromFdInfo {
sb.WriteString(" flags from fd info")
}
}
return sb.String()
}
type oldnameNewnameFile struct {
Oldname, Newname string
}
func NewOldnameNewname(oldname, newname []byte) oldnameNewnameFile {
return oldnameNewnameFile{stringValue(oldname), stringValue(newname)}
}
func (f oldnameNewnameFile) Name() string {
return f.Newname
}
func (f oldnameNewnameFile) FlagsString() string {
return ""
}
func (f oldnameNewnameFile) String() string {
var sb strings.Builder
sb.WriteString("old:")
sb.WriteString(f.Oldname)
sb.WriteString(" ->new:")
sb.WriteString(f.Newname)
sb.WriteString(" (")
sb.WriteString(f.FlagsString())
sb.WriteString(")")
return sb.String()
}
type pathnameFile struct {
Pathname string
}
func NewPathname(pathname []byte) pathnameFile {
return pathnameFile{stringValue(pathname)}
}
func (f pathnameFile) Name() string {
return f.Pathname
}
func (f pathnameFile) FlagsString() string {
return ""
}
func (f pathnameFile) String() string {
var sb strings.Builder
sb.WriteString("pathname:")
sb.WriteString(f.Pathname)
sb.WriteString(" (")
sb.WriteString(f.FlagsString())
sb.WriteString(")")
return sb.String()
}
// As data comes in from arrays, converted to slices, there will be null-bytes at the end..
func stringValue(byteStr []byte) string {
return string(byteStr[:bytes.IndexByte(byteStr, 0)])
}
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