docs/logging_and_backgrounding.txt: new mini-doc

dnsd: remove statics, remove nerly-useless SIGINT handler
crond: correct more of logfile to 0666 (as usual, umask allows
 user to remove unwanted bits).
nameif: print errors to stderr too, not just to syslog

function                                             old     new   delta
udhcp_read_interface                                 308     306      -2
ttl                                                    4       -      -4
fileconf                                               4       -      -4
dnsentry                                               4       -      -4
interrupt                                             19       -     -19
dnsd_main                                           1463    1394     -69
------------------------------------------------------------------------------
(add/remove: 0/4 grow/shrink: 0/2 up/down: 0/-102)           Total: -102 bytes
   text    data     bss     dec     hex filename
 808161     476    7864  816501   c7575 busybox_old
 807994     468    7856  816318   c74be busybox_unstripped

3 files changed, 3 insertions, 5 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 903f3d326..e9f99e39c 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -280,7 +280,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         /* on NOMMU reexec (i.e., background) early */
         if (!(opt & OPT_f)) {
                 bb_daemonize_or_rexec(0 /* flags */, argv);
-                logmode = 0;
+                logmode = LOGMODE_NONE;
         }
 #endif
         if (opt & OPT_S) {
diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index 15b31eb3d..a82fd8c47 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -46,12 +46,10 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 
         opt = getopt32(argv, "fS" USE_FEATURE_UDHCP_PORT("P:", &str_P));
         argv += optind;
-
         if (!(opt & 1)) { /* no -f */
                 bb_daemonize_or_rexec(0, argv);
-                logmode &= ~LOGMODE_STDIO;
+                logmode = LOGMODE_NONE;
         }
-
         if (opt & 2) { /* -S */
                 openlog(applet_name, LOG_PID, LOG_DAEMON);
                 logmode |= LOGMODE_SYSLOG;
diff --git a/networking/udhcp/socket.c b/networking/udhcp/socket.c
index fdb558db4..edf4355b5 100644
--- a/networking/udhcp/socket.c
+++ b/networking/udhcp/socket.c
@@ -57,7 +57,7 @@ int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t
                 }
                 our_ip = (struct sockaddr_in *) &ifr.ifr_addr;
                 *addr = our_ip->sin_addr.s_addr;
-                DEBUG("%s (our ip) = %s", ifr.ifr_name, inet_ntoa(our_ip->sin_addr));
+                DEBUG("ip of %s = %s", interface, inet_ntoa(our_ip->sin_addr));
         }
 
         if (ifindex) {