Re: [PATCH 1/6] lib/cmdline.c: Add backslash support to kernel commandline parsing.

On Fri, 15 Sep 2017 18:14:09 +0100
Al Viro [off-list ref] wrote:

On Fri, Sep 15, 2017 at 07:02:46PM +0200, Michal Suchanek wrote:

quoted

 	for (i = 0; args[i]; i++) {
-		if (isspace(args[i]) && !in_quote)
+		if (isspace(args[i]) && !in_quote && !backslash)
 			break;
-		if (equals == 0) {
-			if (args[i] == '=')
-				equals = i;
+
+		if ((equals == 0) && (args[i] == '='))
+			equals = i;
+
+		if (!backslash) {
+			if ((args[i] == '"') || (args[i] == '\\'))
{
+				if (args[i] == '"')
+					in_quote = !in_quote;
+				if (args[i] == '\\')
+					backslash = 1;
+
+				memmove(args + 1, args, i);
+				args++;
+				i--;
+			}
+		} else {
+			backslash = 0;
 		}
-		if (args[i] == '"')
-			in_quote = !in_quote;
 	}  

... and that makes for Unidiomatic Work With Strings Award for this
September. Using memmove() for string rewrite is almost always bad
taste; in this case it's also (as usual) broken.

Care to share how it is broken?

Thanks

Michal