dnsd: fix several buglets, make smaller

2 files changed, 42 insertions, 64 deletions

diff --git a/include/usage.h b/include/usage.h
index 66f8638f5..615ee4ed7 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -673,7 +673,7 @@
        "        -c      Config filename\n" \
        "        -t      TTL in seconds\n" \
        "        -p      Listening port\n" \
-       "        -i      Listening iface ip (default all)\n" \
+       "        -i      Listening ip (default all)\n" \
        "        -d      Daemonize"
 
 #define dos2unix_trivial_usage \
diff --git a/networking/dnsd.c b/networking/dnsd.c
index fb0c56cce..fd2f421d7 100644
--- a/networking/dnsd.c
+++ b/networking/dnsd.c
@@ -19,13 +19,6 @@
 
 #include "busybox.h"
 
-static const char *fileconf = "/etc/dnsd.conf";
-#define LOCK_FILE       "/var/run/dnsd.lock"
-
-// Must match getopt32 call
-#define OPT_daemon  (option_mask32 & 0x10)
-#define OPT_verbose (option_mask32 & 0x20)
-
 //#define DEBUG 1
 #define DEBUG 0
 
@@ -75,9 +68,16 @@ struct dns_entry {		// element of known name, ip address and reversed ip address
         char name[MAX_HOST_LEN];
 };
 
-static struct dns_entry *dnsentry = NULL;
+static struct dns_entry *dnsentry;
 static uint32_t ttl = DEFAULT_TTL;
 
+static const char *fileconf = "/etc/dnsd.conf";
+
+// Must match getopt32 call
+#define OPT_daemon  (option_mask32 & 0x10)
+#define OPT_verbose (option_mask32 & 0x20)
+
+
 /*
  * Convert host name from C-string to dns length/string.
  */
@@ -135,12 +135,12 @@ static int getfileentry(FILE * fp, struct dns_entry *s)
         while (*r != ' ' && *r != '\t')
                 r++;
         *r++ = '\0';
-        if (sscanf(r, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) {
+        if (sscanf(r, ".%u.%u.%u.%u"+1, &a, &b, &c, &d) != 4) {
                 free(line);
                 goto restart; /* skipping wrong lines */
         }
 
-        sprintf(s->ip, "%u.%u.%u.%u", a, b, c, d);
+        sprintf(s->ip, ".%u.%u.%u.%u"+1, a, b, c, d);
         sprintf(s->rip, ".%u.%u.%u.%u", d, c, b, a);
         undot((uint8_t*)s->rip);
         convname(s->name, (uint8_t*)name);
@@ -185,7 +185,7 @@ static void dnsentryinit(void)
 static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
 {
         int i;
-        struct dns_entry *d=dnsentry;
+        struct dns_entry *d = dnsentry;
 
         do {
 #if DEBUG
@@ -201,17 +201,13 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
                                 if (tolower(qs[i]) != d->name[i])
                                         break;
                         if (i > (int)(d->name[0])) {
-#if DEBUG
-                                fprintf(stderr, " OK");
-#endif
                                 strcpy((char *)as, d->ip);
 #if DEBUG
-                                fprintf(stderr, " as:%s\n", as);
+                                fprintf(stderr, " OK as:%s\n", as);
 #endif
-                                        return 0;
+                                return 0;
                         }
-                } else
-                if (type == REQ_PTR) { /* search by IP-address */
+                } else if (type == REQ_PTR) { /* search by IP-address */
                         if (!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) {
                                 strcpy((char *)as, d->name);
                                 return 0;
@@ -226,7 +222,6 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
 /*
  * Decode message and generate answer
  */
-#define eret(s) do { fputs(s, stderr); return -1; } while (0)
 static int process_packet(uint8_t * buf)
 {
         struct dns_head *head;
@@ -241,11 +236,15 @@ static int process_packet(uint8_t * buf)
         answstr[0] = '\0';
 
         head = (struct dns_head *)buf;
-        if (head->nquer == 0)
-                eret("no queries\n");
+        if (head->nquer == 0) {
+                bb_error_msg("no queries");
+                retunr -1;
+        }
 
-        if (head->flags & 0x8000)
-                eret("ignoring response packet\n");
+        if (head->flags & 0x8000) {
+                bb_error_msg("ignoring response packet");
+                retunr -1;
+        }
 
         from = (void *)&head[1];        //  start of query string
         next = answb = from + strlen((char *)from) + 1 + sizeof(struct dns_prop);   // where to append answer block
@@ -286,8 +285,7 @@ static int process_packet(uint8_t * buf)
                 }
                 memcpy(answstr, &a.s_addr, 4);  // save before a disappears
                 outr.rlen = 4;                  // uint32_t IP
-        }
-        else
+        } else
                 outr.rlen = strlen((char *)answstr) + 1;        // a host name
         outr.r = answstr;                       // 32 bit ip or a host name
         outr.flags |= 0x0400;                   /* authority-bit */
@@ -316,7 +314,7 @@ static int process_packet(uint8_t * buf)
         head->nauth = head->nadd = htons(0);
         head->nquer = htons(1);
 
-        packet_len = next - (void *)buf;
+        packet_len = (uint8_t *)next - buf;
         return packet_len;
 }
 
@@ -325,7 +323,7 @@ static int process_packet(uint8_t * buf)
  */
 static void interrupt(int x)
 {
-        unlink(LOCK_FILE);
+        /* unlink("/var/run/dnsd.lock"); */
         bb_error_msg("interrupt, exiting\n");
         exit(2);
 }
@@ -333,7 +331,7 @@ static void interrupt(int x)
 int dnsd_main(int argc, char **argv);
 int dnsd_main(int argc, char **argv)
 {
-        char *listen_interface = NULL;
+        const char *listen_interface = "0.0.0.0";
         char *sttl, *sport;
         len_and_sockaddr *lsa;
         int udps;
@@ -346,7 +344,7 @@ int dnsd_main(int argc, char **argv)
         if (option_mask32 & 0x4) // -t
                 ttl = xatou_range(sttl, 1, 0xffffffff);
         if (option_mask32 & 0x8) // -p
-                port = xatou_range(sttl, 1, 0xffff);
+                port = xatou_range(sport, 1, 0xffff);
 
         if (OPT_verbose) {
                 bb_info_msg("listen_interface: %s", listen_interface);
@@ -355,7 +353,6 @@ int dnsd_main(int argc, char **argv)
         }
 
         if (OPT_daemon) {
-//FIXME: NOMMU will NOT set LOGMODE_SYSLOG!
 #ifdef BB_NOMMU
                 if (!re_execed)
                         vfork_daemon_rexec(1, 0, argv);
@@ -368,7 +365,7 @@ int dnsd_main(int argc, char **argv)
         dnsentryinit();
 
         signal(SIGINT, interrupt);
-        signal(SIGPIPE, SIG_IGN);
+        /* why? signal(SIGPIPE, SIG_IGN); */
         signal(SIGHUP, SIG_IGN);
 #ifdef SIGTSTP
         signal(SIGTSTP, SIG_IGN);
@@ -377,50 +374,31 @@ int dnsd_main(int argc, char **argv)
         signal(SIGURG, SIG_IGN);
 #endif
 
-        lsa = xhost2sockaddr(listen_interface, port);
+        lsa = xdotted2sockaddr(listen_interface, port);
         udps = xsocket(lsa->sa.sa_family, SOCK_DGRAM, 0);
         xbind(udps, &lsa->sa, lsa->len);
-        // xlisten(udps, 50); - ?!! DGRAM sockets are never listened on I think?
+        /* xlisten(udps, 50); - ?!! DGRAM sockets are never listened on I think? */
         bb_info_msg("Accepting UDP packets on %s",
                         xmalloc_sockaddr2dotted(&lsa->sa, lsa->len));
 
         while (1) {
-                fd_set fdset;
                 int r;
-
-                FD_ZERO(&fdset);
-                FD_SET(udps, &fdset);
-                // Block until a message arrives
-// FIXME: Fantastic. select'ing on just one fd??
-// Why no just block on it doing recvfrom() ?
-                r = select(udps + 1, &fdset, NULL, NULL, NULL);
-                if (r < 0)
-                        bb_perror_msg_and_die("select error");
-                if (r == 0)
-                        bb_perror_msg_and_die("select spurious return");
-
-                /* Can this test ever be false? - yes */
-                if (FD_ISSET(udps, &fdset)) {
-                        socklen_t fromlen = lsa->len;
+                socklen_t fromlen = lsa->len;
 // FIXME: need to get *DEST* address (to which of our addresses
 // this query was directed), and reply from the same address.
 // Or else we can exhibit usual UDP ugliness:
 // [ip1.multihomed.ip2] <=  query to ip1  <= peer
 // [ip1.multihomed.ip2] => reply from ip2 => peer (confused)
-                        r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen);
-                        if (OPT_verbose)
-                                bb_info_msg("Got UDP packet");
-
-                        if (r < 12 || r > 512) {
-                                bb_error_msg("invalid packet size");
-                                continue;
-                        }
-                        if (r <= 0)
-                                continue;
-                        r = process_packet(buf);
-                        if (r <= 0)
-                                continue;
-                        sendto(udps, buf, r, 0, &lsa->sa, fromlen);
+                r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen);
+                if (OPT_verbose)
+                        bb_info_msg("Got UDP packet");
+                if (r < 12 || r > 512) {
+                        bb_error_msg("invalid packet size");
+                        continue;
                 }
+                r = process_packet(buf);
+                if (r <= 0)
+                        continue;
+                sendto(udps, buf, r, 0, &lsa->sa, fromlen);
         }
 }