From 8cd75c4d6b229bb4e3de9264466731e3a32e0133 Mon Sep 17 00:00:00 2001 From: Richard Braun Date: Tue, 26 Feb 2013 22:24:47 +0100 Subject: Add io_select_timeout to the io interface This change fixes a problem that can occur with non-blocking (and also blocking for very short times) select/poll calls. The problem occurs because the timeout is implemented at the client side. For a non-blocking call, this means that (depending on the code path taken in the C library) the client could get a timeout without a full RPC round-trip to the server. Moving the implementation of the timeout to the servers guarantees a full round-trip, and correct results for non-blocking calls. The modifications in this change depend on the availability of the recently added pthread_hurd_cond_timedwait_np function in libpthread. * boot/boot.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * console-client/kbd-repeat.c (repeater_select): Add a timeout parameter. * console-client/pc-mouse.c (repeater_select): Likewise. * console-client/trans.c (io_select_common): New static function. (netfs_S_io_select): Use io_select_common. (netfs_S_io_select_timeout): New function which makes use of io_select_common. * console-client/trans.h (struct consnode): Add a timeout parameter. * hurd/io.defs (io_select_timeout): New MIG routine. * hurd/io_reply.defs (io_select_timeout_reply): New MIG simpleroutine. * hurd/io_request.defs (io_select_timeout_request): Likewise. * libdiskfs/io-select.c (diskfs_S_io_select_timeout): New function. * libnetfs/io-select.c (netfs_S_io_select_timeout): Likewise. * libpipe/pipe.c (pipe_pair_select): Add a timeout parameter. * libpipe/pipe.h (pipe_select_readable): Likewise. (pipe_select_writable): Likewise. (pipe_pair_select): Likewise. * libpipe/pq.h: Include . * libtrivfs/io-select.c (trivfs_S_io_select_timeout): New function. * pfinet/glue-include/linux/sched.h: Include . (interruptible_sleep_on): Function removed, replaced with ... (interruptible_sleep_on_timeout): New function. (schedule): Update to use interruptible_sleep_on_timeout. (schedule_timeout): Likewise. * pfinet/io-ops.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * pfinet/tunnel.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * pflocal/connq.c (connq_listen): Replace noblock with a timeout parameter. * pflocal/connq.h: Include . (connq_listen): Update declaration to replace noblock with a timeout parameter. * pflocal/io.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * pflocal/socket.c (S_socket_accept): Update call to connq_listen to match new declaration. * storeio/io.c (trivfs_S_io_select_timeout): New function. * term/ptyio.c (pty_io_select): Add a timeout parameter. * term/term.h (pty_io_select): Likewise. * term/users.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/fifo.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/firmlink.c (trivfs_S_io_select_timeout): New function. * trans/new-fifo.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/null.c (trivfs_S_io_select_timeout): New function. * trans/streamio.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. --- libpipe/pipe.h | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) (limited to 'libpipe/pipe.h') diff --git a/libpipe/pipe.h b/libpipe/pipe.h index b8e70681..040204d5 100644 --- a/libpipe/pipe.h +++ b/libpipe/pipe.h @@ -126,11 +126,12 @@ extern int pipe_is_readable (struct pipe *pipe, int data_only); extern error_t pipe_wait_readable (struct pipe *pipe, int noblock, int data_only); -extern error_t pipe_select_readable (struct pipe *pipe, int data_only); +extern error_t pipe_select_readable (struct pipe *pipe, struct timespec *tsp, + int data_only); extern error_t pipe_wait_writable (struct pipe *pipe, int noblock); -extern error_t pipe_select_writable (struct pipe *pipe); +extern error_t pipe_select_writable (struct pipe *pipe, struct timespec *tsp); #if defined(__USE_EXTERN_INLINES) || defined(PIPE_DEFINE_EI) @@ -188,12 +189,17 @@ pipe_wait_readable (struct pipe *pipe, int noblock, int data_only) given a chance to read, and if there is still data available thereafter. If DATA_ONLY is true, then `control' packets are ignored. */ PIPE_EI error_t -pipe_select_readable (struct pipe *pipe, int data_only) +pipe_select_readable (struct pipe *pipe, struct timespec *tsp, int data_only) { + error_t err = 0; while (! pipe_is_readable (pipe, data_only) && ! (pipe->flags & PIPE_BROKEN)) - if (pthread_hurd_cond_wait_np (&pipe->pending_read_selects, &pipe->lock)) - return EINTR; - return 0; + { + err = pthread_hurd_cond_timedwait_np (&pipe->pending_read_selects, + &pipe->lock, tsp); + if (err) + break; + } + return err; } /* Block until data can be written to PIPE. If NOBLOCK is true, then @@ -221,13 +227,18 @@ pipe_wait_writable (struct pipe *pipe, int noblock) threads waiting using pipe_wait_writable have been woken and given a chance to write, and if there is still space available thereafter. */ PIPE_EI error_t -pipe_select_writable (struct pipe *pipe) +pipe_select_writable (struct pipe *pipe, struct timespec *tsp) { size_t limit = pipe->write_limit; + error_t err = 0; while (! (pipe->flags & PIPE_BROKEN) && pipe_readable (pipe, 1) >= limit) - if (pthread_hurd_cond_wait_np (&pipe->pending_writes, &pipe->lock)) - return EINTR; - return 0; + { + err = pthread_hurd_cond_timedwait_np (&pipe->pending_writes, + &pipe->lock, tsp); + if (err) + break; + } + return err; } #endif /* Use extern inlines. */ @@ -419,7 +430,8 @@ extern pthread_mutex_t pipe_multiple_lock; waited for on RPIPE. Neither RPIPE or WPIPE should be locked when calling this function (unlike most pipe functions). */ error_t pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe, - int *select_type, int data_only); + struct timespec *tsp, int *select_type, + int data_only); /* ---------------------------------------------------------------- */ /* User-provided functions. */ -- cgit v1.2.3