fix several problems with config parser:

 a bug where it underflows the string
 a bug where it never frees parser_t struct
make read_config() return 0 if parser is NULL,
 make config_close() accept and ignore NULL parser -
 eliminates many if() blocks
reverse the sense of parser bit flags - negative flags
 are harder to grok.
hexdump: revert the change to use config parser, it is BIGGER
 and also requires additional quirks in parser
*: explicitly use PARSER_NORMAL instead of 0

function                                             old     new   delta
login_main                                          1575    1596     +21
config_close                                          18      29     +11
bbunpack                                             383     391      +8
qgravechar                                           106     109      +3
rtnl_tab_initialize                                  121     117      -4
expand                                              1697    1693      -4
man_main                                             717     712      -5
nameif_main                                          674     668      -6
hexdump_main                                         597     591      -6
read_config                                          217     209      -8
dnsd_main                                           1478    1470      -8
sysctl_main                                          203     189     -14
config_open2                                          44      25     -19
make_device                                         1177    1141     -36
config_read                                          597     549     -48
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/11 up/down: 43/-158)         Total: -115 bytes

1 files changed, 4 insertions, 6 deletions

diff --git a/networking/nameif.c b/networking/nameif.c
index 5a3bd60..12c08f1 100644
--- a/networking/nameif.c
+++ b/networking/nameif.c
@@ -160,13 +160,11 @@ int nameif_main(int argc, char **argv)
 			prepend_new_eth_table(&clist, ifname, *argv++);
 		}
 	} else {
+		char *tokens[2];
 		struct parser_t *parser = config_open(fname);
-		if (parser) {
-			char *tokens[2];
-			while (config_read(parser, tokens, 2, 2, "# \t", 0))
-				prepend_new_eth_table(&clist, tokens[0], tokens[1]);
-			config_close(parser);
-		}
+		while (config_read(parser, tokens, 2, 2, "# \t", PARSE_NORMAL))
+			prepend_new_eth_table(&clist, tokens[0], tokens[1]);
+		config_close(parser);
 	}
 
 	ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);