*: replace select-for-one descriptor with poll, it's smaller.

$ ./.cmk bloatcheck
function                                             old     new   delta
readit                                               406     364     -42
syslogd_main                                        1249    1206     -43
traceroute_main                                     4115    4060     -55
mysleep                                              112      45     -67
arpping                                              579     441    -138
tftp                                                1575    1182    -393
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-738)           Total: -738 bytes
   text    data     bss     dec     hex filename
 770580    1051   10764  782395   bf03b busybox_old
 769820    1051   10764  781635   bed43 busybox_unstripped

3 files changed, 37 insertions, 49 deletions

diff --git a/networking/tftp.c b/networking/tftp.c
index 0b25f752d..ac3a86afb 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -23,10 +23,10 @@
 
 #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT
 
-#define TFTP_BLOCKSIZE_DEFAULT 512      /* according to RFC 1350, don't change */
-#define TFTP_TIMEOUT 50000              /* 50ms, in microseconds */
-#define TFTP_MAXTIMEOUT 999000          /* about 1 second, in microseconds */
-#define TFTP_NUM_RETRIES 12             /* number of backed-off retries */
+#define TFTP_BLOCKSIZE_DEFAULT 512      /* according to RFC 1350, don't change */
+#define TFTP_TIMEOUT_MS         50
+#define TFTP_MAXTIMEOUT_MS    2000
+#define TFTP_NUM_RETRIES        12      /* number of backed-off retries */
 
 /* opcodes we support */
 #define TFTP_RRQ   1
@@ -114,9 +114,8 @@ static int tftp( USE_GETPUT(const int cmd,)
                 const char *remotefile, const int localfd,
                 unsigned port, int tftp_bufsize)
 {
-        struct timeval tv;
-        fd_set rfds;
-        int socketfd;
+        struct pollfd pfd[1];
+#define socketfd (pfd[0].fd)
         int len;
         int send_len;
         USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
@@ -124,7 +123,7 @@ static int tftp( USE_GETPUT(const int cmd,)
         uint16_t opcode;
         uint16_t block_nr = 1;
         uint16_t recv_blk;
-        int retries, waittime;
+        int retries, waittime_ms;
         char *cp;
 
         unsigned org_port;
@@ -208,7 +207,7 @@ static int tftp( USE_GETPUT(const int cmd,)
                  * for potential resend */
 
                 retries = TFTP_NUM_RETRIES;     /* re-initialize */
-                waittime = TFTP_TIMEOUT;
+                waittime_ms = TFTP_TIMEOUT_MS;
 
  send_again:
 #if ENABLE_DEBUG_TFTP
@@ -224,11 +223,9 @@ static int tftp( USE_GETPUT(const int cmd,)
 
  recv_again:
                 /* Receive packet */
-                tv.tv_sec = 0;
-                tv.tv_usec = waittime;
-                FD_ZERO(&rfds);
-                FD_SET(socketfd, &rfds);
-                switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
+                /*pfd[0].fd = socketfd;*/
+                pfd[0].events = POLLIN;
+                switch (poll(pfd, 1, waittime_ms)) {
                         unsigned from_port;
                 case 1:
                         from->len = peer_lsa->len;
@@ -258,14 +255,14 @@ static int tftp( USE_GETPUT(const int cmd,)
                         }
 
                         /* exponential backoff with limit */
-                        waittime += waittime/2;
-                        if (waittime > TFTP_MAXTIMEOUT) {
-                                waittime = TFTP_MAXTIMEOUT;
+                        waittime_ms += waittime_ms/2;
+                        if (waittime_ms > TFTP_MAXTIMEOUT_MS) {
+                                waittime_ms = TFTP_MAXTIMEOUT_MS;
                         }
 
                         goto send_again; /* resend last sent pkt */
                 default:
-                        bb_perror_msg("select");
+                        bb_perror_msg("poll");
                         goto ret;
                 }
  process_pkt:
diff --git a/networking/traceroute.c b/networking/traceroute.c
index 236ddbdaf..21921e56d 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -346,10 +346,10 @@ static int optlen;                     /* length of ip options */
 
 
 struct globals {
-        /* last inbound (icmp) packet */
-        unsigned char packet[512];
         struct sockaddr_storage whereto;        /* Who to try to reach */
         struct sockaddr_storage wherefrom;      /* Who we are */
+        /* last inbound (icmp) packet */
+        unsigned char packet[512];
 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
         /* Maximum number of gateways (include room for one noop) */
 #define NGATEWAYS ((int)((MAX_IPOPTLEN - IPOPT_MINOFF - 1) / sizeof(uint32_t)))
@@ -359,7 +359,7 @@ struct globals {
 };
 
 #define G (*ptr_to_globals)
-
+#define INIT_G() PTR_TO_GLOBALS = xzalloc(sizeof(G))
 #define packet    (G.packet   )
 #define whereto   (G.whereto  )
 #define wherefrom (G.wherefrom)
@@ -537,21 +537,15 @@ findsaddr(const struct sockaddr_in *to, struct sockaddr_in *from)
 static int
 wait_for_reply(int sock, struct sockaddr_in *fromp)
 {
-        fd_set fds;
-        struct timeval tvwait;
+        struct pollfd pfd[1];
         int cc = 0;
         socklen_t fromlen = sizeof(*fromp);
 
-        FD_ZERO(&fds);
-        FD_SET(sock, &fds);
-
-        tvwait.tv_sec = waittime;
-        tvwait.tv_usec = 0;
-
-        if (select(sock + 1, &fds, NULL, NULL, &tvwait) > 0)
-                cc = recvfrom(sock, (char *)packet, sizeof(packet), 0,
+        pfd[0].fd = sock;
+        pfd[0].events = POLLIN;
+        if (poll(pfd, 1, waittime * 1000) > 0)
+                cc = recvfrom(sock, packet, sizeof(packet), 0,
                             (struct sockaddr *)fromp, &fromlen);
-
         return cc;
 }
 
@@ -930,7 +924,7 @@ int traceroute_main(int argc, char **argv)
         llist_t *source_route_list = NULL;
 #endif
 
-        PTR_TO_GLOBALS = xzalloc(sizeof(G));
+        INIT_G();
         from = (struct sockaddr_in *)&wherefrom;
         to = (struct sockaddr_in *)&whereto;
 
diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
index 4ac52c640..33518077b 100644
--- a/networking/udhcp/arpping.c
+++ b/networking/udhcp/arpping.c
@@ -37,14 +37,12 @@ struct arpMsg {
 
 int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *interface)
 {
-        int timeout = 2;
-        int s;                  /* socket */
+        int timeout_ms = 2000;
+        struct pollfd pfd[1];
+#define s (pfd[0].fd)           /* socket */
         int rv = 1;             /* "no reply received" yet */
         struct sockaddr addr;   /* for interface name */
         struct arpMsg arp;
-        fd_set fdset;
-        struct timeval tm;
-        unsigned prevTime;
 
         s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
         if (s == -1) {
@@ -80,18 +78,17 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i
         /* wait for arp reply, and check it */
         do {
                 int r;
-                prevTime = monotonic_sec();
-                FD_ZERO(&fdset);
-                FD_SET(s, &fdset);
-                tm.tv_sec = timeout;
-                tm.tv_usec = 0;
-                r = select(s + 1, &fdset, NULL, NULL, &tm);
+                unsigned prevTime = monotonic_us();
+
+                pfd[0].events = POLLIN;
+                r = poll(pfd, 1, timeout_ms);
                 if (r < 0) {
-                        bb_perror_msg("error on ARPING request");
-                        if (errno != EINTR)
+                        if (errno != EINTR) {
+                                bb_perror_msg("poll");
                                 break;
+                        }
                 } else if (r) {
-                        if (recv(s, &arp, sizeof(arp), 0) < 0)
+                        if (read(s, &arp, sizeof(arp)) < 0)
                                 break;
                         if (arp.operation == htons(ARPOP_REPLY)
                          && memcmp(arp.tHaddr, from_mac, 6) == 0
@@ -101,8 +98,8 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i
                                 break;
                         }
                 }
-                timeout -= monotonic_sec() - prevTime;
-        } while (timeout > 0);
+                timeout_ms -= (monotonic_us() - prevTime) / 1000;
+        } while (timeout_ms > 0);
 
  ret:
         close(s);