diff --git a/libbb/bb_strtonum.c b/libbb/bb_strtonum.c
new file mode 100644
index 000000000..7e28eeb86
--- /dev/null
+++ b/libbb/bb_strtonum.c
@@ -0,0 +1,147 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+
+/* On exit: errno = 0 only if there was non-empty, '\0' terminated value
+ * errno = EINVAL if value was not '\0' terminated, but othervise ok
+ *    Return value is still valid, caller should just check whether end[0]
+ *    is a valid terminating char for particular case. OTOH, if caller
+ *    requires '\0' terminated input, [s]he can just check errno == 0.
+ * errno = ERANGE if value had alphanumeric terminating char ("1234abcg").
+ * errno = ERANGE if value is out of range, missing, etc.
+ * errno = ERANGE if value had minus sign for strtouXX (even "-0" is not ok )
+ */
+
+static unsigned long long ret_ERANGE(void)
+{
+	errno = ERANGE; /* this ain't as small as it looks (on glibc) */
+	return ULLONG_MAX;
+}
+
+static unsigned long long handle_errors(unsigned long long v, char **endp, char *endptr)
+{
+	if (endp) *endp = endptr;
+
+	/* Check for the weird "feature":
+	 * a "-" string is apparently a valid "number" for strto[u]l[l]!
+	 * It returns zero and errno is 0! :( */
+	if (endptr[-1] == '-')
+		return ret_ERANGE();
+
+	/* errno is already set to ERANGE by strtoXXX if value overflowed */
+	if (endptr[0]) {
+		/* "1234abcg" or out-of-range? */
+		if (isalnum(endptr[0]) || errno)
+			return ret_ERANGE();
+		/* good number, just suspicious terminator */
+		errno = EINVAL;
+	}
+	return v;
+}
+
+
+unsigned long long bb_strtoull(const char *arg, char **endp, int base)
+{
+	char *endptr;
+
+	/* strtoul("  -4200000000") returns 94967296, errno 0 (!) */
+	/* I don't think that this is right. Preventing this... */
+	if (!isalnum(arg[0])) return ret_ERANGE();
+
+	/* not 100% correct for lib func, but convenient for the caller */
+	errno = 0;
+	return handle_errors(strtoull(arg, &endptr, base), endp, endptr);
+}
+
+long long bb_strtoll(const char *arg, char **endp, int base)
+{
+	char *endptr;
+
+	if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+	errno = 0;
+	return handle_errors(strtoll(arg, &endptr, base), endp, endptr);
+}
+
+#if ULONG_MAX != ULLONG_MAX
+unsigned long bb_strtoul(const char *arg, char **endp, int base)
+{
+	char *endptr;
+
+	if (!isalnum(arg[0])) return ret_ERANGE();
+	errno = 0;
+	return handle_errors(strtoul(arg, &endptr, base), endp, endptr);
+}
+
+long bb_strtol(const char *arg, char **endp, int base)
+{
+	char *endptr;
+
+	if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+	errno = 0;
+	return handle_errors(strtol(arg, &endptr, base), endp, endptr);
+}
+#endif
+
+#if UINT_MAX != ULONG_MAX
+unsigned bb_strtou(const char *arg, char **endp, int base)
+{
+	unsigned long v;
+	char *endptr;
+
+	if (!isalnum(arg[0])) return ret_ERANGE();
+	errno = 0;
+	v = strtoul(arg, &endptr, base);
+	if (v > UINT_MAX) return ret_ERANGE();
+	return handle_errors(v, endp, endptr);
+}
+
+int bb_strtoi(const char *arg, char **endp, int base)
+{
+	long v;
+	char *endptr;
+
+	if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+	errno = 0;
+	v = strtol(arg, &endptr, base);
+	if (v > INT_MAX) return ret_ERANGE();
+	if (v < INT_MIN) return ret_ERANGE();
+	return handle_errors(v, endp, endptr);
+}
+#endif
+
+/* Floating point */
+
+#if 0
+
+#include <math.h>  /* just for HUGE_VAL */
+#define NOT_DIGIT(a) (((unsigned char)(a-'0')) > 9)
+double bb_strtod(const char *arg, char **endp)
+{
+	double v;
+	char *endptr;
+
+	if (arg[0] != '-' && NOT_DIGIT(arg[0])) goto err;
+	errno = 0;
+	v = strtod(arg, &endptr);
+	if (endp) *endp = endptr;
+	if (endptr[0]) {
+		/* "1234abcg" or out-of-range? */
+		if (isalnum(endptr[0]) || errno) {
+ err:
+			errno = ERANGE;
+			return HUGE_VAL;
+		}
+		/* good number, just suspicious terminator */
+		errno = EINVAL;
+	}
+	return v;
+}
+
+#endif