lib/util: Remove sys_poll as it is no longer needed
authorAndrew Bartlett <abartlet@samba.org>
Thu, 9 Feb 2012 02:16:55 +0000 (13:16 +1100)
committerJeremy Allison <jra@samba.org>
Thu, 16 Feb 2012 23:49:21 +0000 (15:49 -0800)
sys_poll() is only needed if the signal pipe is set up and used, but as
no signal handler ever writes to the pipe, this can all be removed.

signal based events are now handled via tevent.

Andrew Bartlett

Signed-off-by: Jeremy Allison <jra@samba.org>
lib/util/select.c
lib/util/select.h
source3/lib/events.c
source3/lib/g_lock.c
source3/lib/util_sock.c
source3/nmbd/nmbd_packets.c
source3/smbd/process.c
source3/winbindd/winbindd_dual.c

index 63be55c..5e66344 100644 (file)
 #include "system/select.h"
 #include "lib/util/select.h"
 
-/* This is here because it allows us to avoid a nasty race in signal handling.
-   We need to guarantee that when we get a signal we get out of a select immediately
-   but doing that involves a race condition. We can avoid the race by getting the
-   signal handler to write to a pipe that is in the select/poll list
-
-   This means all Samba signal handlers should call sys_select_signal().
-*/
-
-static pid_t initialised;
-static int select_pipe[2];
-static volatile unsigned pipe_written, pipe_read;
-
-/*
- * sys_poll expects pollfd's to be a talloc'ed array.
- *
- * It expects the talloc_array_length(fds) >= num_fds+1 to give space
- * to the signal pipe.
- */
-
-int sys_poll(struct pollfd *fds, int num_fds, int timeout)
-{
-       int ret;
-
-       if (talloc_array_length(fds) < num_fds+1) {
-               errno = ENOSPC;
-               return -1;
-       }
-
-       if (initialised != sys_getpid()) {
-               if (pipe(select_pipe) == -1)
-               {
-                       int saved_errno = errno;
-                       DEBUG(0, ("sys_poll: pipe failed (%s)\n",
-                               strerror(errno)));
-                       errno = saved_errno;
-                       return -1;
-               }
-
-               /*
-                * These next two lines seem to fix a bug with the Linux
-                * 2.0.x kernel (and probably other UNIXes as well) where
-                * the one byte read below can block even though the
-                * select returned that there is data in the pipe and
-                * the pipe_written variable was incremented. Thanks to
-                * HP for finding this one. JRA.
-                */
-
-               if(set_blocking(select_pipe[0],0)==-1)
-                       smb_panic("select_pipe[0]: O_NONBLOCK failed");
-               if(set_blocking(select_pipe[1],0)==-1)
-                       smb_panic("select_pipe[1]: O_NONBLOCK failed");
-
-               initialised = sys_getpid();
-       }
-
-       ZERO_STRUCT(fds[num_fds]);
-       fds[num_fds].fd = select_pipe[0];
-       fds[num_fds].events = POLLIN|POLLHUP;
-
-       errno = 0;
-       ret = poll(fds, num_fds+1, timeout);
-
-       if ((ret >= 0) && (fds[num_fds].revents & (POLLIN|POLLHUP|POLLERR))) {
-               char c;
-               int saved_errno = errno;
-
-               if (read(select_pipe[0], &c, 1) == 1) {
-                       pipe_read += 1;
-
-                       /* Mark Weaver <mark-clist@npsl.co.uk> pointed out a critical
-                          fix to ensure we don't lose signals. We must always
-                          return -1 when the select pipe is set, otherwise if another
-                          fd is also ready (so ret == 2) then we used to eat the
-                          byte in the pipe and lose the signal. JRA.
-                       */
-                       ret = -1;
-#if 0
-                       /* JRA - we can use this to debug the signal messaging... */
-                       DEBUG(0,("select got %u signal\n", (unsigned int)c));
-#endif
-                       errno = EINTR;
-               } else {
-                       ret -= 1;
-                       errno = saved_errno;
-               }
-       }
-
-       return ret;
-}
-
 int sys_poll_intr(struct pollfd *fds, int num_fds, int timeout)
 {
        int orig_timeout = timeout;
index bfc78a9..fa1970e 100644 (file)
@@ -24,7 +24,6 @@
 
 /* The following definitions come from lib/util/select.c  */
 
-int sys_poll(struct pollfd *fds, int num_fds, int timeout);
 int sys_poll_intr(struct pollfd *fds, int num_fds, int timeout);
 
 #endif
index 77589f8..c71876c 100644 (file)
@@ -101,14 +101,9 @@ bool event_add_to_poll_args(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
        fds = *pfds;
        num_pollfds = *pnum_pfds;
 
-       /*
-        * The +1 is for the sys_poll calling convention. It expects
-        * an array 1 longer for the signal pipe
-        */
-
-       if (talloc_array_length(fds) < num_pollfds + num_fds + 1) {
+       if (talloc_array_length(fds) < num_pollfds + num_fds) {
                fds = talloc_realloc(mem_ctx, fds, struct pollfd,
-                                          num_pollfds + num_fds + 1);
+                                          num_pollfds + num_fds);
                if (fds == NULL) {
                        DEBUG(10, ("talloc_realloc failed\n"));
                        return false;
@@ -338,7 +333,7 @@ static int s3_event_loop_once(struct tevent_context *ev, const char *location)
                return -1;
        }
 
-       ret = sys_poll(state->pfds, num_pfds, timeout);
+       ret = poll(state->pfds, num_pfds, timeout);
        if (ret == -1 && errno != EINTR) {
                tevent_debug(ev, TEVENT_DEBUG_FATAL,
                             "poll() failed: %d:%s\n",
index 1fd8ae9..1011584 100644 (file)
@@ -395,11 +395,11 @@ NTSTATUS g_lock_lock(struct g_lock_ctx *ctx, const char *name,
                 */
 
                /*
-                * We allocate 2 entries here. One is needed anyway for
-                * sys_poll and in the clustering case we might have to add
-                * the ctdb fd. This avoids the realloc then.
+                * We allocate 1 entries here. In the clustering case
+                * we might have to add the ctdb fd. This avoids the
+                * realloc then.
                 */
-               pollfds = talloc_array(talloc_tos(), struct pollfd, 2);
+               pollfds = talloc_array(talloc_tos(), struct pollfd, 1);
                if (pollfds == NULL) {
                        status = NT_STATUS_NO_MEMORY;
                        break;
@@ -425,8 +425,8 @@ NTSTATUS g_lock_lock(struct g_lock_ctx *ctx, const char *name,
                select_timeout = timeval_min(&select_timeout,
                                             &timeout_remaining);
 
-               ret = sys_poll(pollfds, num_pollfds,
-                              timeval_to_msec(select_timeout));
+               ret = poll(pollfds, num_pollfds,
+                          timeval_to_msec(select_timeout));
 
                /*
                 * We're not *really interested in the actual flags. We just
index dcc41bb..69e33f7 100644 (file)
@@ -1604,7 +1604,7 @@ int poll_one_fd(int fd, int events, int timeout, int *revents)
        int ret;
        int saved_errno;
 
-       fds = talloc_zero_array(talloc_tos(), struct pollfd, 2);
+       fds = talloc_zero_array(talloc_tos(), struct pollfd, 1);
        if (fds == NULL) {
                errno = ENOMEM;
                return -1;
@@ -1612,7 +1612,7 @@ int poll_one_fd(int fd, int events, int timeout, int *revents)
        fds[0].fd = fd;
        fds[0].events = events;
 
-       ret = sys_poll(fds, 1, timeout);
+       ret = poll(fds, 1, timeout);
 
        /*
         * Assign whatever poll did, even in the ret<=0 case.
index edac6f6..81e2f7f 100644 (file)
@@ -1935,7 +1935,7 @@ bool listen_for_packets(struct messaging_context *msg, bool run_election)
        event_add_to_poll_args(nmbd_event_context(), NULL,
                               &fds, &num_sockets, &timeout);
 
-       pollrtn = sys_poll(fds, num_sockets, timeout);
+       pollrtn = poll(fds, num_sockets, timeout);
 
        if (run_events_poll(nmbd_event_context(), pollrtn, fds, num_sockets)) {
                return False;
index 2f8f88f..f295a59 100644 (file)
@@ -967,7 +967,7 @@ static NTSTATUS smbd_server_connection_loop_once(struct tevent_context *ev_ctx,
                int sav;
                START_PROFILE(smbd_idle);
 
-               ret = sys_poll(conn->pfds, num_pfds, timeout);
+               ret = poll(conn->pfds, num_pfds, timeout);
                sav = errno;
 
                END_PROFILE(smbd_idle);
index d0bcd3b..f11dae7 100644 (file)
@@ -1507,7 +1507,7 @@ static bool fork_domain_child(struct winbindd_child *child)
                                (unsigned int)tp->tv_sec, (unsigned int)tp->tv_usec ));
                }
 
-               ret = sys_poll(pfds, num_pfds, timeout);
+               ret = poll(pfds, num_pfds, timeout);
 
                if (run_events_poll(winbind_event_context(), ret,
                                    pfds, num_pfds)) {