dhcpd: remember and record hostnames; optimize get_option

dumpleases: show hostnames

function                                             old     new   delta
add_lease                                            230     292     +62
send_offer                                           403     421     +18
send_ACK                                             232     249     +17
read_leases                                          249     258      +9
dumpleases_main                                      604     609      +5
nobody_responds_to_arp                                84      86      +2
udhcp_end_option                                      32      30      -2
udhcp_get_option                                     222     171     -51
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 6/2 up/down: 113/-53)            Total: 60 bytes

1 files changed, 6 insertions, 3 deletions

diff --git a/networking/udhcp/dumpleases.c b/networking/udhcp/dumpleases.c
index c0d515d28..1558f8848 100644
--- a/networking/udhcp/dumpleases.c
+++ b/networking/udhcp/dumpleases.c
@@ -47,8 +47,9 @@ int dumpleases_main(int argc UNUSED_PARAM, char **argv)
 
         fd = xopen(file, O_RDONLY);
 
-        printf("Mac Address       IP-Address      Expires %s\n", (opt & OPT_a) ? "at" : "in");
-        /*     "00:00:00:00:00:00 255.255.255.255 Wed Jun 30 21:49:08 1993" */
+        printf("Mac Address       IP Address      Host Name           Expires %s\n", (opt & OPT_a) ? "at" : "in");
+        /*     "00:00:00:00:00:00 255.255.255.255 ABCDEFGHIJKLMNOPQRS Wed Jun 30 21:49:08 1993" */
+        /*     "123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 */
 
         if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
                 return 0;
@@ -64,7 +65,9 @@ int dumpleases_main(int argc UNUSED_PARAM, char **argv)
                         fmt = ":%02x";
                 }
                 addr.s_addr = lease.yiaddr;
-                printf(" %-15s ", inet_ntoa(addr));
+                /* actually, 15+1 and 19+1, +1 is a space between columns */
+                /* lease.hostname is char[20] and is always NUL terminated */
+                printf(" %-16s%-20s", inet_ntoa(addr), lease.hostname);
                 expires_abs = ntohl(lease.expires) + written_at;
                 if (expires_abs <= curr) {
                         puts("expired");