mirror of
https://github.com/safing/portmaster
synced 2025-09-02 02:29:12 +00:00
107 lines
2.7 KiB
Go
107 lines
2.7 KiB
Go
//go:build linux
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package proc
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import (
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"errors"
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"io/fs"
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"os"
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"strconv"
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"github.com/safing/portbase/log"
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"github.com/safing/portmaster/network/socket"
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)
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// GetPID returns the already existing pid of the given socket info or searches for it.
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// This also acts as a getter for socket.Info.PID, as locking for that occurs here.
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func GetPID(socketInfo socket.Info) (pid int) {
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// Get currently assigned PID to the socket info.
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currentPid := socketInfo.GetPID()
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// If the current PID already is valid (ie. not unidentified), return it immediately.
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if currentPid != socket.UndefinedProcessID {
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return currentPid
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}
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// Find PID for the given UID and inode.
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pid = findPID(socketInfo.GetUIDandInode())
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// Set the newly found PID on the socket info.
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socketInfo.SetPID(pid)
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// Return found PID.
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return pid
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}
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// findPID returns the pid of the given uid and socket inode.
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func findPID(uid, inode int) (pid int) {
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socketName := "socket:[" + strconv.Itoa(inode) + "]"
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// Always update pid table (it has a call limiter anyway)
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updatePids()
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// Get all pids for the given uid.
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pids, ok := getPidsByUser(uid)
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if !ok {
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return socket.UndefinedProcessID
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}
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// Look through the PIDs in reverse order, because higher/newer PIDs will be more likely to
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// be searched for.
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for j := len(pids) - 1; j >= 0; j-- {
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if pidHasSocket(pids[j], socketName) {
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return pids[j]
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}
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}
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return socket.UndefinedProcessID
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}
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func pidHasSocket(pid int, socketName string) bool {
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socketBase := "/proc/" + strconv.Itoa(pid) + "/fd"
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entries := readDirNames(socketBase)
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if len(entries) == 0 {
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return false
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}
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socketBase += "/"
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// Look through the FDs in reverse order, because higher/newer FDs will be
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// more likely to be searched for.
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for i := len(entries) - 1; i >= 0; i-- {
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link, err := os.Readlink(socketBase + entries[i])
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if err != nil {
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if !errors.Is(err, fs.ErrNotExist) {
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log.Warningf("proc: failed to read link /proc/%d/fd/%s: %s", pid, entries[i], err)
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}
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continue
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}
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if link == socketName {
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return true
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}
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}
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return false
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}
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// readDirNames only reads the directory names. Using os.ReadDir() would call `lstat` on every
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// resulting directory name, which we don't need. This function will be called a lot, so we should
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// refrain from unnecessary work.
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func readDirNames(dir string) (names []string) {
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file, err := os.Open(dir)
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if err != nil {
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if !errors.Is(err, fs.ErrNotExist) {
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log.Warningf("proc: could not open directory %s: %s", dir, err)
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}
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return
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}
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defer func() {
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_ = file.Close()
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}()
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names, err = file.Readdirnames(0)
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if err != nil {
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log.Warningf("proc: could not get entries from directory %s: %s", dir, err)
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return []string{}
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}
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return
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}
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