[dm-devel] [PATCH 2/8] libmultipath: cleanup add_feature

[Benjamin Marzinski]

add_feature() didn't correctly handle feature strings that used
whitespace other than spaces, which the kernel allows. It also didn't
allow adding features with multiple tokens. When it looked to see if the
feature string to be added already existed, it didn't check if the match
was part of a larger token. Finally, it did unnecessary work.  By using
asprintf() to create the string, the function can be signifcantly
simplified.

Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 libmultipath/structs.c | 49 +++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

diff --git a/libmultipath/structs.c b/libmultipath/structs.c
index 1f9945e0..0f16c071 100644
--- a/libmultipath/structs.c
+++ b/libmultipath/structs.c
@@ -602,23 +602,33 @@ int add_feature(char **f, const char *n)
 {
 	int c = 0, d, l;
 	char *e, *t;
+	const char *p;
 
 	if (!f)
 		return 1;
 
 	/* Nothing to do */
-	if (!n || *n == '0')
+	if (!n || *n == '\0')
 		return 0;
 
-	if (strchr(n, ' ') != NULL) {
-		condlog(0, "internal error: feature \"%s\" contains spaces", n);
+	l = strlen(n);
+	if (isspace(*n) || isspace(*(n + l - 1))) {
+		condlog(0, "internal error: feature \"%s\" has leading or trailing spaces", n);
 		return 1;
 	}
 
+	p = n;
+	d = 1;
+	while (*p != '\0') {
+		if (isspace(*p) && !isspace(*(p + 1)) && *(p + 1) != '\0')
+			d++;
+		p++;
+	}
+
 	/* default feature is null */
 	if(!*f)
 	{
-		l = asprintf(&t, "1 %s", n);
+		l = asprintf(&t, "%0d %s", d, n);
 		if(l == -1)
 			return 1;
 
@@ -627,35 +637,24 @@ int add_feature(char **f, const char *n)
 	}
 
 	/* Check if feature is already present */
-	if (strstr(*f, n))
-		return 0;
+	e = *f;
+	while ((e = strstr(e, n)) != NULL) {
+		if (isspace(*(e - 1)) &&
+		    (isspace(*(e + l)) || *(e + l) == '\0'))
+			return 0;
+		e += l;
+	}
 
 	/* Get feature count */
 	c = strtoul(*f, &e, 10);
-	if (*f == e || (*e != ' ' && *e != '\0')) {
+	if (*f == e || (!isspace(*e) && *e != '\0')) {
 		condlog(0, "parse error in feature string \"%s\"", *f);
 		return 1;
 	}
-
-	/* Add 1 digit and 1 space */
-	l = strlen(e) + strlen(n) + 2;
-
-	c++;
-	/* Check if we need more digits for feature count */
-	for (d = c; d >= 10; d /= 10)
-		l++;
-
-	t = calloc(1, l + 1);
-	if (!t)
+	c += d;
+	if (asprintf(&t, "%0d%s %s", c, e, n) < 0)
 		return 1;
 
-	/* e: old feature string with leading space, or "" */
-	if (*e == ' ')
-		while (*(e + 1) == ' ')
-			e++;
-
-	snprintf(t, l + 1, "%0d%s %s", c, e, n);
-
 	free(*f);
 	*f = t;
 
-- 
2.17.2