introduce safe_poll (fixes a problem in top)

function                                             old     new   delta
safe_poll                                              -      77     +77
svlogd_main                                         1470    1466      -4
zcip_main                                           1530    1524      -6
forkexec                                            1345    1338      -7
decode_format_string                                 795     788      -7
collect_blk                                          474     467      -7
buffer_pread                                         540     532      -8
tftp                                                1182    1172     -10
microcom_main                                        763     749     -14
arpping                                              441     424     -17
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/9 up/down: 77/-80)             Total: -3 bytes
   text    data     bss     dec     hex filename
 770162    1034   10404  781600   bed20 busybox_old
 770158    1034   10404  781596   bed1c busybox_unstripped

5 files changed, 14 insertions, 19 deletions

diff --git a/networking/httpd.c b/networking/httpd.c
index cedec800f..92a07107d 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1073,13 +1073,9 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
 		}
 
 		/* Now wait on the set of sockets */
-		count = poll(pfd, 3, -1);
+		count = safe_poll(pfd, 3, -1);
 		if (count <= 0) {
 #if 0
-			if (errno == EINTR)
-				continue;
-#endif
-#if 0
 			if (waitpid(pid, &status, WNOHANG) <= 0) {
 				/* Weird. CGI didn't exit and no fd's
 				 * are ready, yet poll returned?! */
diff --git a/networking/tftp.c b/networking/tftp.c
index ac3a86afb..59f53ae4a 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -225,7 +225,7 @@ static int tftp( USE_GETPUT(const int cmd,)
 		/* Receive packet */
 		/*pfd[0].fd = socketfd;*/
 		pfd[0].events = POLLIN;
-		switch (poll(pfd, 1, waittime_ms)) {
+		switch (safe_poll(pfd, 1, waittime_ms)) {
 			unsigned from_port;
 		case 1:
 			from->len = peer_lsa->len;
@@ -262,7 +262,7 @@ static int tftp( USE_GETPUT(const int cmd,)
 
 			goto send_again; /* resend last sent pkt */
 		default:
-			bb_perror_msg("poll");
+			/*bb_perror_msg("poll"); - done in safe_poll */
 			goto ret;
 		}
  process_pkt:
diff --git a/networking/traceroute.c b/networking/traceroute.c
index 21921e56d..2d09c7197 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -543,7 +543,7 @@ wait_for_reply(int sock, struct sockaddr_in *fromp)
 
 	pfd[0].fd = sock;
 	pfd[0].events = POLLIN;
-	if (poll(pfd, 1, waittime * 1000) > 0)
+	if (safe_poll(pfd, 1, waittime * 1000) > 0)
 		cc = recvfrom(sock, packet, sizeof(packet), 0,
 			    (struct sockaddr *)fromp, &fromlen);
 	return cc;
diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
index 33518077b..7b702d8f3 100644
--- a/networking/udhcp/arpping.c
+++ b/networking/udhcp/arpping.c
@@ -81,12 +81,9 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i
 		unsigned prevTime = monotonic_us();
 
 		pfd[0].events = POLLIN;
-		r = poll(pfd, 1, timeout_ms);
+		r = safe_poll(pfd, 1, timeout_ms);
 		if (r < 0) {
-			if (errno != EINTR) {
-				bb_perror_msg("poll");
-				break;
-			}
+			break;
 		} else if (r) {
 			if (read(s, &arp, sizeof(arp)) < 0)
 				break;
diff --git a/networking/zcip.c b/networking/zcip.c
index 2f0b5a7fb..63846ebef 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -300,7 +300,12 @@ int zcip_main(int argc, char **argv)
 
 		VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
 				timeout_ms, intf, nprobes, nclaims);
-		switch (poll(fds, 1, timeout_ms)) {
+
+		switch (safe_poll(fds, 1, timeout_ms)) {
+
+		default:
+			/*bb_perror_msg("poll"); - done in safe_poll */
+			return EXIT_FAILURE;
 
 		// timeout
 		case 0:
@@ -388,6 +393,7 @@ int zcip_main(int argc, char **argv)
 				break;
 			} // switch (state)
 			break; // case 0 (timeout)
+
 		// packets arriving
 		case 1:
 			// We need to adjust the timeout in case we didn't receive
@@ -519,13 +525,9 @@ int zcip_main(int argc, char **argv)
 				nclaims = 0;
 				break;
 			} // switch state
-
 			break; // case 1 (packets arriving)
-		default:
-			why = "poll";
-			goto bad;
 		} // switch poll
-	}
+	} // while (1)
  bad:
 	bb_perror_msg("%s, %s", intf, why);
 	return EXIT_FAILURE;