libbb: fix bb_strtol[l]'s check for "-". Hopefully closes bug 4174

function                                             old     new   delta
bb_strtol                                             82      85      +3
handle_errors                                         75      66      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 3/-9)               Total: -6 bytes

diff --git a/libbb/bb_strtonum.c b/libbb/bb_strtonum.c
index 2433f1f1f2439dd525463b41a9e5428ee1450a9c..4a0da0ae0e88e30c9e4a545251ae1a5a7c1cb7c9 100644 (file)
--- a/libbb/bb_strtonum.c
+++ b/libbb/bb_strtonum.c
@@ -18,6 +18,16 @@
  * errno = ERANGE if value is out of range, missing, etc.
  * errno = ERANGE if value had minus sign for strtouXX (even "-0" is not ok )
  *    return value is all-ones in this case.
+ *
+ * Test code:
+ * char *endptr;
+ * const char *minus = "-";
+ * errno = 0;
+ * bb_strtoi(minus, &endptr, 0); // must set ERANGE
+ * printf("minus:%p endptr:%p errno:%d EINVAL:%d\n", minus, endptr, errno, EINVAL);
+ * errno = 0;
+ * bb_strtoi("-0-", &endptr, 0); // must set EINVAL and point to second '-'
+ * printf("endptr[0]:%c errno:%d EINVAL:%d\n", endptr[0], errno, EINVAL);
  */
 
 static unsigned long long ret_ERANGE(void)
@@ -38,11 +48,6 @@ static unsigned long long handle_errors(unsigned long long v, char **endp, char
                /* good number, just suspicious terminator */
                errno = EINVAL;
        }
-       /* 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();
        return v;
 }
 
@@ -67,7 +72,12 @@ long long FAST_FUNC bb_strtoll(const char *arg, char **endp, int base)
        unsigned long long v;
        char *endptr;
 
-       if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+       /* Check for the weird "feature":
+        * a "-" string is apparently a valid "number" for strto[u]l[l]!
+        * It returns zero and errno is 0! :( */
+       char first = (arg[0] != '-' ? arg[0] : arg[1]);
+       if (!isalnum(first)) return ret_ERANGE();
+
        errno = 0;
        v = strtoll(arg, &endptr, base);
        return handle_errors(v, endp, endptr);
@@ -90,7 +100,9 @@ long FAST_FUNC bb_strtol(const char *arg, char **endp, int base)
        long v;
        char *endptr;
 
-       if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+       char first = (arg[0] != '-' ? arg[0] : arg[1]);
+       if (!isalnum(first)) return ret_ERANGE();
+
        errno = 0;
        v = strtol(arg, &endptr, base);
        return handle_errors(v, endp, endptr);
@@ -115,7 +127,9 @@ int FAST_FUNC bb_strtoi(const char *arg, char **endp, int base)
        long v;
        char *endptr;
 
-       if (arg[0] != '-' && !isalnum(arg[0])) return ret_ERANGE();
+       char first = (arg[0] != '-' ? arg[0] : arg[1]);
+       if (!isalnum(first)) return ret_ERANGE();
+
        errno = 0;
        v = strtol(arg, &endptr, base);
        if (v > INT_MAX) return ret_ERANGE();