Initial commit after restructure

process/proc/processfinder.go

@@ -0,0 +1,163 @@
+// Copyright Safing ICS Technologies GmbH. Use of this source code is governed by the AGPL license that can be found in the LICENSE file.
+
+package proc
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strconv"
+	"sync"
+	"syscall"
+
+	"github.com/Safing/safing-core/log"
+)
+
+var (
+	pidsByUserLock sync.Mutex
+	pidsByUser     = make(map[int][]int)
+)
+
+func GetPidOfInode(uid, inode int) (int, bool) {
+	pidsByUserLock.Lock()
+	defer pidsByUserLock.Unlock()
+
+	pidsUpdated := false
+
+	// get pids of user, update if missing
+	pids, ok := pidsByUser[uid]
+	if !ok {
+		// log.Trace("process: no processes of user, updating table")
+		updatePids()
+		pidsUpdated = true
+		pids, ok = pidsByUser[uid]
+	}
+	if ok {
+		// if user has pids, start checking them first
+		var checkedUserPids []int
+		for _, possiblePID := range pids {
+			if findSocketFromPid(possiblePID, inode) {
+				return possiblePID, true
+			}
+			checkedUserPids = append(checkedUserPids, possiblePID)
+		}
+		// if we fail on the first run and have not updated, update and check the ones we haven't tried so far.
+		if !pidsUpdated {
+			// log.Trace("process: socket not found in any process of user, updating table")
+			// update
+			updatePids()
+			// sort for faster search
+			for i, j := 0, len(checkedUserPids)-1; i < j; i, j = i+1, j-1 {
+				checkedUserPids[i], checkedUserPids[j] = checkedUserPids[j], checkedUserPids[i]
+			}
+			len := len(checkedUserPids)
+			// check unchecked pids
+			for _, possiblePID := range pids {
+				// only check if not already checked
+				if sort.SearchInts(checkedUserPids, possiblePID) == len {
+					if findSocketFromPid(possiblePID, inode) {
+						return possiblePID, true
+					}
+				}
+			}
+		}
+	}
+
+	// check all other pids
+	// log.Trace("process: socket not found in any process of user, checking all pids")
+	// TODO: find best order for pidsByUser for best performance
+	for possibleUID, pids := range pidsByUser {
+		if possibleUID != uid {
+			for _, possiblePID := range pids {
+				if findSocketFromPid(possiblePID, inode) {
+					return possiblePID, true
+				}
+			}
+		}
+	}
+
+	return -1, false
+}
+
+func findSocketFromPid(pid, inode int) bool {
+	socketName := fmt.Sprintf("socket:[%d]", inode)
+	entries := readDirNames(fmt.Sprintf("/proc/%d/fd", pid))
+	if len(entries) == 0 {
+		return false
+	}
+
+	for _, entry := range entries {
+		link, err := os.Readlink(fmt.Sprintf("/proc/%d/fd/%s", pid, entry))
+		if err != nil {
+			if !os.IsNotExist(err) {
+				log.Warningf("process: failed to read link /proc/%d/fd/%s: %s", pid, entry, err)
+			}
+			continue
+		}
+		if link == socketName {
+			return true
+		}
+	}
+
+	return false
+}
+
+func updatePids() {
+	pidsByUser = make(map[int][]int)
+
+	entries := readDirNames("/proc")
+	if len(entries) == 0 {
+		return
+	}
+
+entryLoop:
+	for _, entry := range entries {
+		pid, err := strconv.ParseInt(entry, 10, 32)
+		if err != nil {
+			continue entryLoop
+		}
+
+		statData, err := os.Stat(fmt.Sprintf("/proc/%d", pid))
+		if err != nil {
+			log.Warningf("process: could not stat /proc/%d: %s", pid, err)
+			continue entryLoop
+		}
+		sys, ok := statData.Sys().(*syscall.Stat_t)
+		if !ok {
+			log.Warningf("process: unable to parse /proc/%d: wrong type", pid)
+			continue entryLoop
+		}
+
+		pids, ok := pidsByUser[int(sys.Uid)]
+		if ok {
+			pidsByUser[int(sys.Uid)] = append(pids, int(pid))
+		} else {
+			pidsByUser[int(sys.Uid)] = []int{int(pid)}
+		}
+
+	}
+
+	for _, slice := range pidsByUser {
+		for i, j := 0, len(slice)-1; i < j; i, j = i+1, j-1 {
+			slice[i], slice[j] = slice[j], slice[i]
+		}
+	}
+
+}
+
+func readDirNames(dir string) (names []string) {
+	file, err := os.Open(dir)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			log.Warningf("process: could not open directory %s: %s", dir, err)
+		}
+		return
+	}
+	defer file.Close()
+	names, err = file.Readdirnames(0)
+	if err != nil {
+		log.Warningf("process: could not get entries from direcotry %s: %s", dir, err)
+		return []string{}
+	}
+	return
+}