Fix out of bounds error in strace.go (#348)

* strace.go: fix index out of bounds error and add nil checking for regex match

Signed-off-by: Max Fisher <[email protected]>

* strace_test.go: add missing comma

Signed-off-by: Max Fisher <[email protected]>

* strace_test.go: fix typo in test

Signed-off-by: Max Fisher <[email protected]>

* strace.go: make regex consistent with other ones

Signed-off-by: Max Fisher <[email protected]>

Signed-off-by: Max Fisher <[email protected]>

Author: maxfisher-g

internal/strace/strace.go

@@ -40,7 +40,8 @@ var (
 	unlinkPatten = regexp.MustCompile(`0x[a-f\d]+ ([^)]+)`)
 
 	// unlinkat(0x4 /tmp/pip-pip-egg-info-ng4_5gp_/temps.egg-info, 0x7fe0031c9a10 top_level.txt, 0x0)
-	unlinkatPattern = regexp.MustCompile(`0x[a-f\d]+ ([^,]+), 0x[a-f\d]+ ([^,]+), 0x[a-f\d]+`)
+	// unlinkat(AT_FDCWD /app, 0x5569a7e83380 /app/vendor/composer/e06632ca, 0x200)
+	unlinkatPattern = regexp.MustCompile(`[^\s]+ ([^,]+), 0x[a-f\d]+ ([^,]+), 0x[a-f\d]+`)
 )
 
 type FileInfo struct {
@@ -244,12 +245,18 @@ func (r *Result) parseSyscall(syscall, args string) error {
 		r.recordFileAccess(path, true, false, false)
 	case "unlink":
 		match := unlinkPatten.FindStringSubmatch(args)
+		if match == nil {
+			return fmt.Errorf("Failed to parse unlink args: %s", args)
+		}
 		path := match[1]
 		log.Debug("unlink",
 			"path", path)
 		r.recordFileAccess(path, false, false, true)
 	case "unlinkat":
 		match := unlinkatPattern.FindStringSubmatch(args)
+		if match == nil {
+			return fmt.Errorf("Failed to parse unlinkat args: %s", args)
+		}
 		path := joinPaths(match[1], match[2])
 		log.Debug("unlinkat",
 			"path", path)

internal/strace/strace_test.go

@@ -202,6 +202,14 @@ func TestParseFilesOneEntry(t *testing.T) {
 				Delete: true,
 			},
 		},
+		{
+			name:  "unlinkat_2",
+			input: "I0907 23:56:32.113900     302 strace.go:631] [  48:  48] rm X unlinkat(AT_FDCWD /app, 0x5569a7e83380 /app/vendor/composer/e06632ca, 0x200) = 0 (0x0) (69.951µs)",
+			want: strace.FileInfo{
+				Path:   "/app/vendor/composer/e06632ca",
+				Delete: true,
+			},
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {