*: 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

1 files changed, 15 insertions, 18 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: