ulogd: improve integer option parsing

The `value` union member in `struct config_entry` is declared as `int`
since basically the beginning in e07722e46001 ("config stuff added").
The parsing was switched from the original `atoi()` in 015849995f7f
("Fix hexadecimal parsing in config file") to `strtoul()`.

Switch the function for parsing to the signed `strtol()` variant since
the result will be stored in a signed int, and it makes sense to support
negative numbers. Detect when `strtol()` does not properly consume the
whole argument and return a new format error. Also check the numerical
value to make sure the signed int does not overflow, in which case
a new range error is returned.

Unfortunately there is no `strtoi()` which would do the proper range
check itself, so the intermediate `long` and range-check for `int` is
required. I also considered changing the `value` union member from
`int` to `long`, which would make it possible to use the parsed value
as-is. But since this is part of the api towards plugins (including
third party) such a potentially breaking change felt unwarranted. This
also means that still only 16bit integer values are *guaranteed* to
work, although most platforms use bigger widths for int.

Signed-off-by: Corubba Smith <corubba@gmx.de>
Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/ulogd.c b/src/ulogd.c
index 7260aeb..c844767 100644
--- a/src/ulogd.c
+++ b/src/ulogd.c
@@ -293,6 +293,16 @@ int ulogd_parse_configfile(const char *section, struct config_keyset *ce)
 		else
 			ulogd_log(ULOGD_ERROR, "string value is too long\n");
 		break;
+	case -ERRINTFORMAT:
+		ulogd_log(ULOGD_ERROR,
+		          "integer has invalid format for key \"%s\"\n",
+		          config_errce->key);
+		break;
+	case -ERRINTRANGE:
+		ulogd_log(ULOGD_ERROR,
+		          "integer is out of range for key \"%s\"\n",
+		          config_errce->key);
+		break;
 	}
 
 	return ULOGD_IRET_ERR;