The ffsinfo utility uses atol() to parse numeric values out of optarg

strings.  This isn't necessarily a bug, but it can be slightly inconvenient,
because atol() doesn't know how to parse hexadecimal or octal numbers and at
least one of the options of ffsinfo(8) would be easier to use if it did.

Changing atol() -> strtol() allows one to use hex masks for -l MASK, i.e.:

orion:/a/freebsd/src/sbin/ffsinfo# ./ffsinfo -l 0x3ff /

PR:		73110
Submitted by:	keramida
MFC after:	2 weeks

1 files changed, 10 insertions, 3 deletions

diff --git a/sbin/ffsinfo/ffsinfo.c b/sbin/ffsinfo/ffsinfo.c
index 3e3a8c246557..e556be82c7e2 100644
--- a/sbin/ffsinfo/ffsinfo.c
+++ b/sbin/ffsinfo/ffsinfo.c
@@ -63,6 +63,7 @@ static const char rcsid[] =
 
 #include <ctype.h>
 #include <err.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <libufs.h>
 #include <paths.h>
@@ -148,19 +149,25 @@ main(int argc, char **argv)
 	while ((ch=getopt(argc, argv, "g:i:l:o:")) != -1) {
 		switch(ch) {
 		case 'g':
-			cfg_cg=atol(optarg);
+			cfg_cg=strtol(optarg, NULL, 0);
+			if(errno == EINVAL||errno == ERANGE)
+				err(1, "%s", optarg);
 			if(cfg_cg < -1) {
 				usage();
 			}
 			break;
 		case 'i':
-			cfg_in=atol(optarg);
+			cfg_in=strtol(optarg, NULL, 0);
+			if(errno == EINVAL||errno == ERANGE)
+				err(1, "%s", optarg);
 			if(cfg_in < 0) {
 				usage();
 			}
 			break; 
 		case 'l':
-			cfg_lv=atol(optarg);
+			cfg_lv=strtol(optarg, NULL, 0);
+			if(errno == EINVAL||errno == ERANGE)
+				err(1, "%s", optarg);
 			if(cfg_lv < 0x1||cfg_lv > 0x3ff) {
 				usage();
 			}