os/exec: check for escaped backslash when ParseCommandArgs

Given the following string "cmd /a\ b" to ParseCommandArgs now it should
return "cmd" and ["/a b"] not ["/a\", "b"], because the space after a
is escaped using backslash.

2 files changed, 36 insertions, 5 deletions

diff --git a/lib/os/exec/exec.go b/lib/os/exec/exec.go
index bc661f3f..0fed245c 100644
--- a/lib/os/exec/exec.go
+++ b/lib/os/exec/exec.go
@@ -17,10 +17,12 @@ import (
 
 //
 // ParseCommandArgs parse the input string into command and arguments.
-// This function detect possible single, double, or back quote on arguments.
+// This function detect single, double, or back quote on arguments; and
+// escaped spaces using backslash.
 //
 func ParseCommandArgs(in string) (cmd string, args []string) {
 	var (
+		prev    rune
 		quote   rune
 		cmdArgs []string
 	)
@@ -40,21 +42,38 @@ func ParseCommandArgs(in string) (cmd string, args []string) {
 			} else {
 				sb.WriteRune(r)
 			}
+			prev = r
 			continue
 		}
 		if r == '\'' || r == '"' || r == '`' {
 			quote = r
+			prev = r
+			continue
+		}
+		if r == '\\' {
+			if prev == '\\' {
+				sb.WriteRune(r)
+				prev = 0
+			} else {
+				prev = r
+			}
 			continue
 		}
 		if r == ' ' || r == '\t' {
-			arg := sb.String()
-			if len(arg) > 0 {
-				cmdArgs = append(cmdArgs, sb.String())
+			if prev == '\\' {
+				sb.WriteRune(r)
+			} else {
+				arg := sb.String()
+				if len(arg) > 0 {
+					cmdArgs = append(cmdArgs, sb.String())
+				}
+				sb.Reset()
 			}
-			sb.Reset()
+			prev = r
 			continue
 		}
 		sb.WriteRune(r)
+		prev = r
 	}
 
 	arg := sb.String()
diff --git a/lib/os/exec/exec_test.go b/lib/os/exec/exec_test.go
index 90771dbb..38e089d0 100644
--- a/lib/os/exec/exec_test.go
+++ b/lib/os/exec/exec_test.go
@@ -41,6 +41,18 @@ func TestParseCommandArg(t *testing.T) {
 		in:      "a `b'c`",
 		expCmd:  `a`,
 		expArgs: []string{`b'c`},
+	}, {
+		in: `a\ b c\ d`,
+		expCmd: "a b",
+		expArgs: []string{"c d"},
+	}, {
+		in: `a\\ b c\\ d`,
+		expCmd: `a\`,
+		expArgs: []string{"b", `c\`, "d"},
+	}, {
+		in: `a\\\ b c\\\ d`,
+		expCmd: `a\ b`,
+		expArgs: []string{`c\ d`},
 	}}
 
 	for _, c := range cases {