syslogd: do not need to poll(), we can just block in read().

function                                             old     new   delta
syslogd_main                                        1206    1106    -100
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-100)           Total: -100 bytes
   text    data     bss     dec     hex filename
 769820    1051   10764  781635   bed43 busybox_old
 769702    1051   10764  781517   beccd busybox_unstripped

1 files changed, 23 insertions, 30 deletions

diff --git a/sysklogd/syslogd.c b/sysklogd/syslogd.c
index ae3f1a2eb..f27bd8379 100644
--- a/sysklogd/syslogd.c
+++ b/sysklogd/syslogd.c
@@ -471,8 +471,7 @@ static void do_syslogd(void) ATTRIBUTE_NORETURN;
 static void do_syslogd(void)
 {
         struct sockaddr_un sunx;
-        struct pollfd pfd[1];
-#define sock_fd (pfd[0].fd)
+        int sock_fd;
         char *dev_log_name;
 
         /* Set up signal handlers */
@@ -526,40 +525,34 @@ static void do_syslogd(void)
                         (char*)"syslogd started: BusyBox v" BB_VER, 0);
 
         for (;;) {
-                /*pfd[0].fd = sock_fd;*/
-                pfd[0].events = POLLIN;
-                pfd[0].revents = 0;
-                if (poll(pfd, 1, -1) < 0) { /* -1: no timeout */
-                        if (errno == EINTR) {
-                                /* alarm may have happened */
+                size_t sz;
+
+                sz = read(sock_fd, G.recvbuf, MAX_READ - 1);
+                if (sz <= 0) {
+                        if (sz == 0)
+                                continue; /* EOF from unix socket??? */
+                        if (errno == EINTR) /* alarm may have happened */
                                 continue;
-                        }
-                        bb_perror_msg_and_die("poll");
+                        bb_perror_msg_and_die("read from /dev/log");
                 }
 
-                if (pfd[0].revents) {
-                        int i;
-                        i = read(sock_fd, G.recvbuf, MAX_READ - 1);
-                        if (i <= 0)
-                                bb_perror_msg_and_die("UNIX socket error");
-                        /* TODO: maybe suppress duplicates? */
+                /* TODO: maybe suppress duplicates? */
 #if ENABLE_FEATURE_REMOTE_LOG
-                        /* We are not modifying log messages in any way before send */
-                        /* Remote site cannot trust _us_ anyway and need to do validation again */
-                        if (G.remoteAddr) {
-                                if (-1 == G.remoteFD) {
-                                        G.remoteFD = socket(G.remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
-                                }
-                                if (-1 != G.remoteFD) {
-                                        /* send message to remote logger, ignore possible error */
-                                        sendto(G.remoteFD, G.recvbuf, i, MSG_DONTWAIT,
-                                                &G.remoteAddr->sa, G.remoteAddr->len);
-                                }
+                /* We are not modifying log messages in any way before send */
+                /* Remote site cannot trust _us_ anyway and need to do validation again */
+                if (G.remoteAddr) {
+                        if (-1 == G.remoteFD) {
+                                G.remoteFD = socket(G.remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
+                        }
+                        if (-1 != G.remoteFD) {
+                                /* send message to remote logger, ignore possible error */
+                                sendto(G.remoteFD, G.recvbuf, sz, MSG_DONTWAIT,
+                                        &G.remoteAddr->sa, G.remoteAddr->len);
                         }
-#endif
-                        G.recvbuf[i] = '\0';
-                        split_escape_and_log(G.recvbuf, i);
                 }
+#endif
+                G.recvbuf[sz] = '\0';
+                split_escape_and_log(G.recvbuf, sz);
         } /* for */
 }