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;