Module: sip-router Branch: sr_3.0 Commit: 4cfd8e1d074e9bb76b20ca3b5722f4a02dd29f15 URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=4cfd8e1… Author: Andrei Pelinescu-Onciul &lt;andrei(a)iptel.org&gt; Committer: Andrei Pelinescu-Onciul &lt;andrei(a)iptel.org&gt; Date: Sat Jun 19 00:44:24 2010 +0200 io_wait: kqueue: handle ENOENT and more robust error handling - handle also ENOENT (along EBADF) when kevent fails due to errors in the changelist. ENOENT can be returned in the following valid scenario: fd scheduled for delayed removal from the watched fd list, fd closed (which automatically removes the fd from the kqueue watched list), new opened fd which gets the same number, delayed changes applied (kevent()). - treat all the other kevent errors or EV_ERRORs in a similar way but log them (at BUG() level). - return POLLERR|POLLHUP for EV_EOF with a non-null fflags. (only kqueue, meaning *bsd and darwin are affected by this fix) (cherry picked from commit 8966d0a1787152fa64d1f78321ee539116bd448a) --- io_wait.h | 92 +++++++++++++++++++++++++++++++++++++------------------------ 1 files changed, 56 insertions(+), 36 deletions(-) diff --git a/io_wait.h b/io_wait.h index b110b6b..c28f53d 100644 --- a/io_wait.h +++ b/io_wait.h @@ -259,34 +259,33 @@ static inline int kq_ev_change(io_wait_h* h, int fd, int filter, int flag, again: n=kevent(h->kq_fd, h->kq_changes, h->kq_nchanges, 0, 0, &tspec); if (unlikely(n == -1)){ - if (likely(errno == EBADF)) { + if (unlikely(errno == EINTR)) goto again; + else { + /* for a detailed explanation of what follows see + io_wait_loop_kqueue EV_ERROR case */ + if (unlikely(!(errno == EBADF || errno == ENOENT))) + BUG("kq_ev_change: kevent flush changes failed" + " (unexpected error): %s [%d]\n", + strerror(errno), errno); + /* ignore error even if it's not a EBADF/ENOENT */ /* one of the file descriptors is bad, probably already closed => try to apply changes one-by-one */ for (r = 0; r < h->kq_nchanges; r++) { retry2: n = kevent(h->kq_fd, &h->kq_changes[r], 1, 0, 0, &tspec); if (n==-1) { - if (errno == EBADF) - continue; /* skip over it */ - if (errno == EINTR) + if (unlikely(errno == EINTR)) goto retry2; - LOG(L_ERR, "ERROR: io_watch_add: kevent flush changes" - " failed: %s [%d]\n", - strerror(errno), errno); - /* shift the array */ - memmove(&h->kq_changes[0], &h->kq_changes[r+1], - sizeof(h->kq_changes[0])* - (h->kq_nchanges-r-1)); - h->kq_nchanges-=(r+1); - return -1; + /* for a detailed explanation of what follows see + io_wait_loop_kqueue EV_ERROR case */ + if (unlikely(!(errno == EBADF || errno == ENOENT))) + BUG("kq_ev_change: kevent flush changes failed:" + " (unexpected error) %s [%d] (%d/%d)\n", + strerror(errno), errno, + r, h->kq_nchanges); + continue; /* skip over it */ } } - } else if (errno == EINTR) goto again; - else { - LOG(L_ERR, "ERROR: io_watch_add: kevent flush changes" - " failed: %s [%d]\n", strerror(errno), errno); - h->kq_nchanges=0; /* reset changes array */ - return -1; } } h->kq_nchanges=0; /* changes array is empty */ @@ -1118,17 +1117,18 @@ again: n=kevent(h->kq_fd, h->kq_changes, apply_changes, h->kq_array, h->fd_no, &tspec); if (unlikely(n==-1)){ - if (errno==EINTR) goto again; /* signal, ignore it */ - else if (errno==EBADF) { + if (unlikely(errno==EINTR)) goto again; /* signal, ignore it */ + else { + /* for a detailed explanation of what follows see below + the EV_ERROR case */ + if (unlikely(!(errno==EBADF || errno==ENOENT))) + BUG("io_wait_loop_kqueue: kevent: unexpected error" + " %s [%d]\n", strerror(errno), errno); /* some of the FDs in kq_changes are bad (already closed) and there is not enough space in kq_array to return all of them back */ apply_changes = h->fd_no; goto again; - }else{ - LOG(L_ERR, "ERROR: io_wait_loop_kqueue: kevent:" - " %s [%d]\n", strerror(errno), errno); - goto error; } } /* remove applied changes */ @@ -1148,14 +1148,13 @@ again: r, n, h->kq_array[r].ident, (long)h->kq_array[r].udata, h->kq_array[r].flags); #endif - if (unlikely((h->kq_array[r].flags & EV_ERROR) && - (h->kq_array[r].data == EBADF || - h->kq_array[r].udata == 0))){ + if (unlikely((h->kq_array[r].flags & EV_ERROR) || + h->kq_array[r].udata == 0)){ /* error in changes: we ignore it if it has to do with a bad fd or update==0. It can be caused by trying to remove an already closed fd: race between adding something to the - changes array, close() and applying the changes. - E.g. for ser tcp: tcp_main sends a fd to child fore reading + changes array, close() and applying the changes (EBADF). + E.g. for ser tcp: tcp_main sends a fd to child for reading => deletes it from the watched fds => the changes array will contain an EV_DELETE for it. Before the changes are applied (they are at the end of the main io_wait loop, @@ -1163,6 +1162,16 @@ again: to tcp_main by a sender (send fail) is processed and causes the fd to be closed. When the changes are applied => error for the EV_DELETE attempt of a closed fd. + Something similar can happen when a fd is scheduled + for removal, is close()'ed before being removed and + re-opened(a new sock. get the same fd). When the + watched fd changes will be applied the fd will be valid + (so no EBADF), but it's not already watch => ENOENT. + We report a BUG for the other errors (there's nothing + constructive we can do if we get an error we don't know + how to handle), but apart from that we ignore it in the + idea that it is better apply the rest of the changes, + rather then dropping all of them. */ /* example EV_ERROR for trying to delete a read watched fd, @@ -1176,9 +1185,12 @@ again: udata = 0x0 } */ - if (h->kq_array[r].data != EBADF) - LOG(L_INFO, "INFO: io_wait_loop_kqueue: kevent error on " - "fd %ld: %s [%ld]\n", (long)h->kq_array[r].ident, + if (h->kq_array[r].data != EBADF && + h->kq_array[r].data != ENOENT) + BUG("io_wait_loop_kqueue: kevent unexpected error on " + "fd %ld udata %lx: %s [%ld]\n", + (long)h->kq_array[r].ident, + (long)h->kq_array[r].udata, strerror(h->kq_array[r].data), (long)h->kq_array[r].data); }else{ @@ -1186,20 +1198,28 @@ again: if (likely(h->kq_array[r].filter==EVFILT_READ)){ revents=POLLIN | (((int)!(h->kq_array[r].flags & EV_EOF)-1)&POLLHUP) | - (((int)!(h->kq_array[r].flags & EV_ERROR)-1)&POLLERR); + (((int)!((h->kq_array[r].flags & EV_EOF) && + h->kq_array[r].fflags != 0) - 1)&POLLERR); while(fm->type && (fm->events & revents) && (handle_io(fm, revents, -1)>0) && repeat); }else if (h->kq_array[r].filter==EVFILT_WRITE){ revents=POLLOUT | (((int)!(h->kq_array[r].flags & EV_EOF)-1)&POLLHUP) | - (((int)!(h->kq_array[r].flags & EV_ERROR)-1)&POLLERR); + (((int)!((h->kq_array[r].flags & EV_EOF) && + h->kq_array[r].fflags != 0) - 1)&POLLERR); while(fm->type && (fm->events & revents) && (handle_io(fm, revents, -1)>0) && repeat); + }else{ + BUG("io_wait_loop_kqueue: unknown filter: kqueue: event " + "%d/%d: fd=%d, filter=%d, flags=0x%x, fflags=0x%x," + " data=%lx, udata=%lx\n", + r, n, h->kq_array[r].ident, h->kq_array[r].filter, + h->kq_array[r].flags, h->kq_array[r].fflags, + (long)h->kq_array[r].data, (long)h->kq_array[r].udata); } } } } while(unlikely(orig_changes)); -error: return n; } #endif