POSIX says that 0[xX] prefix is _optional_ even in base 16 case, make it

really so.

"If the value of base is 16, the characters 0x or 0X may optionally
precede the sequence of letters and digits, following the sign if
present."

Found by:       joerg

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/libc/stdlib/strtoul.c b/lib/libc/stdlib/strtoul.c
index 2146a98..a8e3736 100644
--- a/lib/libc/stdlib/strtoul.c
+++ b/lib/libc/stdlib/strtoul.c
@@ -73,7 +73,11 @@ strtoul(const char * __restrict nptr, char ** __restrict endptr, int base)
 			c = *s++;
 	}
 	if ((base == 0 || base == 16) &&
-	    c == '0' && (*s == 'x' || *s == 'X')) {
+	    c == '0' && (*s == 'x' || *s == 'X') &&
+	    ((s[1] >= 'a' && s[1] <= 'f') ||
+	     (s[1] >= 'A' && s[1] <= 'F') ||
+	     (s[1] >= '0' && s[1] <= '9'))
+	   ) {
 		c = s[1];
 		s += 2;
 		base = 16;