*: 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

editors/vi.c

@@ -237,7 +237,8 @@ static char *yank_delete(char *, char *, int, int);	// yank text[] into register
 static void show_help(void);	// display some help info
 static void rawmode(void);	// set "raw" mode on tty
 static void cookmode(void);	// return to "cooked" mode on tty
-static int mysleep(int);	// sleep for 'h' 1/100 seconds
+// sleep for 'h' 1/100 seconds, return 1/0 if stdin is (ready for read)/(not ready)
+static int mysleep(int);
 static char readit(void);	// read (maybe cursor) key from stdin
 static char get_one_char(void);	// read 1 char from stdin
 static int file_size(const char *);   // what is the byte size of "fn"
@@ -2134,17 +2135,11 @@ static void catch_sig(int sig)
 
 static int mysleep(int hund)	// sleep for 'h' 1/100 seconds
 {
-	fd_set rfds;
+	struct pollfd pfd[1];
-	struct timeval tv;
 
-	// Don't hang- Wait 5/100 seconds-  1 Sec= 1000000
+	pfd[0].fd = 0;
-	fflush(stdout);
+	pfd[0].events = POLLIN;
-	FD_ZERO(&rfds);
+	return poll(pfd, 1, hund*10) > 0;
-	FD_SET(0, &rfds);
-	tv.tv_sec = 0;
-	tv.tv_usec = hund * 10000;
-	select(1, &rfds, NULL, NULL, &tv);
-	return FD_ISSET(0, &rfds);
 }
 
 #define readbuffer bb_common_bufsiz1
@@ -2217,25 +2212,20 @@ static char readit(void)	// read (maybe cursor) key from stdin
 		if (n <= 0)
 			return 0;       // error
 		if (readbuffer[0] == 27) {
-			fd_set rfds;
-			struct timeval tv;
-
 			// This is an ESC char. Is this Esc sequence?
 			// Could be bare Esc key. See if there are any
 			// more chars to read after the ESC. This would
 			// be a Function or Cursor Key sequence.
-			FD_ZERO(&rfds);
+			struct pollfd pfd[1];
-			FD_SET(0, &rfds);
+			pfd[0].fd = 0;
-			tv.tv_sec = 0;
+			pfd[0].events = POLLIN;
-			tv.tv_usec = 50000;	// Wait 5/100 seconds- 1 Sec=1000000
+			// Wait 50 ms
-
 			// keep reading while there are input chars and room in buffer
-			while (select(1, &rfds, NULL, NULL, &tv) > 0 && n <= (MAX_LINELEN - 5)) {
+			while (poll(pfd, 1, 50) > 0 && n <= (MAX_LINELEN - 5)) {
 				// read the rest of the ESC string
-				int r = read(0, (void *) (readbuffer + n), MAX_LINELEN - n);
+				int r = read(0, readbuffer + n, MAX_LINELEN - n);
-				if (r > 0) {
+				if (r > 0)
 					n += r;
-				}
 			}
 		}
 		readed_for_parse = n;

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_BLOCKSIZE_DEFAULT 512      /* according to RFC 1350, don't change */
-#define TFTP_TIMEOUT 50000		/* 50ms, in microseconds */
+#define TFTP_TIMEOUT_MS         50
-#define TFTP_MAXTIMEOUT 999000		/* about 1 second, in microseconds */
+#define TFTP_MAXTIMEOUT_MS    2000
-#define TFTP_NUM_RETRIES 12 		/* number of backed-off retries */
+#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;
+	struct pollfd pfd[1];
-	fd_set rfds;
+#define socketfd (pfd[0].fd)
-	int socketfd;
 	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;
+		/*pfd[0].fd = socketfd;*/
-		tv.tv_usec = waittime;
+		pfd[0].events = POLLIN;
-		FD_ZERO(&rfds);
+		switch (poll(pfd, 1, waittime_ms)) {
-		FD_SET(socketfd, &rfds);
-		switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
 			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;
+			waittime_ms += waittime_ms/2;
-			if (waittime > TFTP_MAXTIMEOUT) {
+			if (waittime_ms > TFTP_MAXTIMEOUT_MS) {
-				waittime = TFTP_MAXTIMEOUT;
+				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:

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 pollfd pfd[1];
-	struct timeval tvwait;
 	int cc = 0;
 	socklen_t fromlen = sizeof(*fromp);
 
-	FD_ZERO(&fds);
+	pfd[0].fd = sock;
-	FD_SET(sock, &fds);
+	pfd[0].events = POLLIN;
-
+	if (poll(pfd, 1, waittime * 1000) > 0)
-	tvwait.tv_sec = waittime;
+		cc = recvfrom(sock, packet, sizeof(packet), 0,
-	tvwait.tv_usec = 0;
-
-	if (select(sock + 1, &fds, NULL, NULL, &tvwait) > 0)
-		cc = recvfrom(sock, (char *)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;
 

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 timeout_ms = 2000;
-	int s;                  /* socket */
+	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();
+		unsigned prevTime = monotonic_us();
-		FD_ZERO(&fdset);
+
-		FD_SET(s, &fdset);
+		pfd[0].events = POLLIN;
-		tm.tv_sec = timeout;
+		r = poll(pfd, 1, timeout_ms);
-		tm.tv_usec = 0;
-		r = select(s + 1, &fdset, NULL, NULL, &tm);
 		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;
+		timeout_ms -= (monotonic_us() - prevTime) / 1000;
-	} while (timeout > 0);
+	} while (timeout_ms > 0);
 
  ret:
 	close(s);

shell/ash.c

@@ -11589,6 +11589,7 @@ readcmd(int argc, char **argv)
 #endif
 #if ENABLE_ASH_READ_TIMEOUT
 	if (ts.tv_sec || ts.tv_usec) {
+// TODO: replace with poll, it is smaller
 		FD_ZERO(&set);
 		FD_SET(0, &set);
 

sysklogd/syslogd.c

@@ -471,8 +471,8 @@ static void do_syslogd(void) ATTRIBUTE_NORETURN;
 static void do_syslogd(void)
 {
 	struct sockaddr_un sunx;
-	int sock_fd;
+	struct pollfd pfd[1];
-	fd_set fds;
+#define sock_fd (pfd[0].fd)
 	char *dev_log_name;
 
 	/* Set up signal handlers */
@@ -526,20 +526,20 @@ static void do_syslogd(void)
 			(char*)"syslogd started: BusyBox v" BB_VER, 0);
 
 	for (;;) {
-		FD_ZERO(&fds);
+		/*pfd[0].fd = sock_fd;*/
-		FD_SET(sock_fd, &fds);
+		pfd[0].events = POLLIN;
-
+		pfd[0].revents = 0;
-		if (select(sock_fd + 1, &fds, NULL, NULL, NULL) < 0) {
+		if (poll(pfd, 1, -1) < 0) { /* -1: no timeout */
 			if (errno == EINTR) {
 				/* alarm may have happened */
 				continue;
 			}
-			bb_perror_msg_and_die("select");
+			bb_perror_msg_and_die("poll");
 		}
 
-		if (FD_ISSET(sock_fd, &fds)) {
+		if (pfd[0].revents) {
 			int i;
-			i = recv(sock_fd, G.recvbuf, MAX_READ - 1, 0);
+			i = read(sock_fd, G.recvbuf, MAX_READ - 1);
 			if (i <= 0)
 				bb_perror_msg_and_die("UNIX socket error");
 			/* TODO: maybe suppress duplicates? */
@@ -559,7 +559,7 @@ static void do_syslogd(void)
 #endif
 			G.recvbuf[i] = '\0';
 			split_escape_and_log(G.recvbuf, i);
-		} /* FD_ISSET() */
+		}
 	} /* for */
 }