refactors psscanner

internal/psscanner/proclist.go

@@ -0,0 +1,103 @@
+package psscanner
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var procDirReader = func() ([]os.FileInfo, error) {
+	return ioutil.ReadDir("/proc")
+}
+
+var procStatusReader = func(pid int) ([]byte, error) {
+	statPath := fmt.Sprintf("/proc/%d/status", pid)
+	return ioutil.ReadFile(statPath)
+}
+
+var cmdLineReader = func(pid int) ([]byte, error) {
+	cmdPath := fmt.Sprintf("/proc/%d/cmdline", pid)
+	return ioutil.ReadFile(cmdPath)
+}
+
+type procList map[int]string
+
+func (pl procList) refresh(eventCh chan string) error {
+	pids, err := getPIDs()
+	if err != nil {
+		return err
+	}
+
+	for i := len(pids) - 1; i >= 0; i-- {
+		pid := pids[i]
+		_, ok := pl[pid]
+		if !ok {
+			cmd, err := getCmd(pid)
+			if err != nil {
+				cmd = "???" // process probably terminated
+			}
+			uid, err := getUID(pid)
+			if err != nil {
+				uid = "???"
+			}
+			eventCh <- fmt.Sprintf("CMD: UID=%-4s PID=%-6d | %s", uid, pid, cmd)
+			// if print {
+			// 	log.Printf("\x1b[31;1mCMD: UID=%-4s PID=%-6d | %s\x1b[0m\n", uid, pid, cmd)
+			// }
+			pl[pid] = cmd
+		}
+	}
+
+	return nil
+}
+
+func getPIDs() ([]int, error) {
+	proc, err := procDirReader()
+	if err != nil {
+		return nil, fmt.Errorf("opening proc dir: %v", err)
+	}
+
+	pids := make([]int, 0)
+	for _, f := range proc {
+		if f.IsDir() {
+			name := f.Name()
+			pid, err := strconv.Atoi(name)
+			if err != nil {
+				continue // not a pid
+			}
+			pids = append(pids, pid)
+		}
+	}
+	return pids, nil
+}
+
+func getCmd(pid int) (string, error) {
+	cmd, err := cmdLineReader(pid)
+	if err != nil {
+		return "", err
+	}
+	for i := 0; i < len(cmd); i++ {
+		if cmd[i] == 0 {
+			cmd[i] = 32
+		}
+	}
+	return string(cmd), nil
+}
+
+func getUID(pid int) (string, error) {
+	stat, err := procStatusReader(pid)
+	if err != nil {
+		return "", err
+	}
+	lines := strings.Split(string(stat), "\n")
+	if len(lines) < 9 {
+		return "", fmt.Errorf("no uid information")
+	}
+	uidL := strings.Split(lines[8], "\t")
+	if len(uidL) < 2 {
+		return "", fmt.Errorf("uid line read incomplete")
+	}
+	return uidL[1], nil
+}

internal/psscanner/proclist_test.go

@@ -0,0 +1,40 @@
+package psscanner
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestGetCmd(t *testing.T) {
+	tests := []struct {
+		pid     int
+		cmdLine []byte
+		cmdErr  error
+		cmd     string
+		err     string
+	}{
+		{pid: 1, cmdLine: []byte("abc"), cmdErr: nil, cmd: "abc", err: ""},
+	}
+
+	for _, tt := range tests {
+		restore := mockCmdLineReader(tt.cmdLine, tt.cmdErr)
+		cmd, err := getCmd(tt.pid)
+		if cmd != tt.cmd {
+			t.Errorf("Wrong cmd line returned: got %s but want %s", cmd, tt.cmd)
+		}
+		if (err != nil || tt.err != "") && fmt.Sprintf("%v", err) != tt.err {
+			t.Errorf("Wrong error returned: got %v but want %s", err, tt.err)
+		}
+		restore()
+	}
+}
+
+func mockCmdLineReader(cmdLine []byte, err error) (restore func()) {
+	oldFunc := cmdLineReader
+	cmdLineReader = func(pid int) ([]byte, error) {
+		return cmdLine, err
+	}
+	return func() {
+		cmdLineReader = oldFunc
+	}
+}

internal/psscanner/psscanner.go

@@ -0,0 +1,21 @@
+package psscanner
+
+type PSScanner struct{}
+
+func NewPSScanner() *PSScanner {
+	return &PSScanner{}
+}
+
+func (p *PSScanner) Run(triggerCh chan struct{}) (chan string, chan error) {
+	eventCh := make(chan string, 100)
+	errCh := make(chan error)
+	pl := make(procList)
+
+	go func() {
+		for {
+			<-triggerCh
+			pl.refresh(eventCh)
+		}
+	}()
+	return eventCh, errCh
+}