diff options
| -rw-r--r-- | trans/fifo.c | 145 |
1 files changed, 79 insertions, 66 deletions
diff --git a/trans/fifo.c b/trans/fifo.c index e3317593..8ce5916a 100644 --- a/trans/fifo.c +++ b/trans/fifo.c @@ -158,83 +158,92 @@ open_hook (struct trivfs_peropen *po) error_t err = 0; int flags = po->openmodes; + if (flags & (O_READ | O_WRITE)) + { + mutex_lock (&active_fifo_lock); + /* Wait until the active fifo has changed so that CONDITION is true. */ -#define WAIT(condition) \ +#define WAIT(condition, noblock_err) \ while (!err && !(condition)) \ if (flags & O_NONBLOCK) \ - err = EWOULDBLOCK; \ + { \ + err = noblock_err; \ + break; \ + } \ else if (hurd_condition_wait (&active_fifo_changed, &active_fifo_lock)) \ err = EINTR; - mutex_lock (&active_fifo_lock); - - if (flags & O_READ) - /* When opening for read, what we do depends on what mode this server is - running in. The default (if ONE_READER is set) is to only allow one - reader at a time, with additional opens for read blocking here until - the old reader goes away; otherwise, we allow multiple readers. If - WAIT_FOR_WRITER is true, then once we've created a fifo, we also block - until someone opens it for writing; otherwise, the first read will - block until someone writes something. */ - { - if (one_reader) - /* Wait until there isn't any active fifo, so we can make one. */ - WAIT (!active_fifo || !active_fifo->readers); - - if (!err && active_fifo == NULL) - /* No other readers, and indeed, no fifo; make one. */ - err = pipe_create (fifo_pipe_class, &active_fifo); - if (!err) + if (flags & O_READ) + /* When opening for read, what we do depends on what mode this server + is running in. The default (if ONE_READER is set) is to only + allow one reader at a time, with additional opens for read + blocking here until the old reader goes away; otherwise, we allow + multiple readers. If WAIT_FOR_WRITER is true, then once we've + created a fifo, we also block until someone opens it for writing; + otherwise, the first read will block until someone writes + something. */ { - pipe_add_reader (active_fifo); - condition_broadcast (&active_fifo_changed); - /* We'll unlock ACTIVE_FIFO_LOCK below; the writer code won't make - us block because we've ensured that there's a reader for it. */ + if (one_reader) + /* Wait until there isn't any active fifo, so we can make one. */ + WAIT (!active_fifo || !active_fifo->readers, EWOULDBLOCK); - if (wait_for_writer) - /* Wait until there's a writer. */ + if (!err && active_fifo == NULL) + /* No other readers, and indeed, no fifo; make one. */ { - WAIT (active_fifo->writers); - if (err) - /* Back out the new pipe creation. */ + err = pipe_create (fifo_pipe_class, &active_fifo); + if (! err) + active_fifo->flags &= ~PIPE_BROKEN; /* Avoid immediate EOF. */ + } + if (!err) + { + pipe_add_reader (active_fifo); + condition_broadcast (&active_fifo_changed); + /* We'll unlock ACTIVE_FIFO_LOCK below; the writer code won't + make us block because we've ensured that there's a reader + for it. */ + + if (wait_for_writer) + /* Wait until there's a writer. */ { - pipe_remove_reader (active_fifo); - active_fifo = NULL; - condition_broadcast (&active_fifo_changed); + WAIT (active_fifo->writers, 0); + if (err) + /* Back out the new pipe creation. */ + { + pipe_remove_reader (active_fifo); + active_fifo = NULL; + condition_broadcast (&active_fifo_changed); + } } } - else - /* Otherwise prevent an immediate eof. */ - active_fifo->flags &= ~PIPE_BROKEN; } - } - if (!err && (flags & O_WRITE)) - /* Open the active_fifo for writing. If WAIT_FOR_READER is true, then we - block until there's someone to read what we wrote, otherwise, if - there's no fifo, we create one, which we just write into and leave it - for someone to read later. */ - { - if (wait_for_reader) - /* Wait until there's a fifo to write to. */ - WAIT (active_fifo && active_fifo->readers); - if (!err && active_fifo == NULL) - /* No other readers, and indeed, no fifo; make one. */ + if (!err && (flags & O_WRITE)) + /* Open the active_fifo for writing. If WAIT_FOR_READER is true, + then we block until there's someone to read what we wrote, + otherwise, if there's no fifo, we create one, which we just write + into and leave it for someone to read later. */ { - err = pipe_create (fifo_pipe_class, &active_fifo); + if (wait_for_reader) + /* Wait until there's a fifo to write to. */ + WAIT (active_fifo && active_fifo->readers, ENXIO); + if (!err && active_fifo == NULL) + /* No other readers, and indeed, no fifo; make one. */ + { + err = pipe_create (fifo_pipe_class, &active_fifo); + if (!err) + active_fifo->flags &= ~PIPE_BROKEN; + } if (!err) - active_fifo->flags &= ~PIPE_BROKEN; - } - if (!err) - { - pipe_add_writer (active_fifo); - condition_broadcast (&active_fifo_changed); + { + pipe_add_writer (active_fifo); + condition_broadcast (&active_fifo_changed); + } } - } - po->hook = active_fifo; + po->hook = active_fifo; - mutex_unlock (&active_fifo_lock); + mutex_unlock (&active_fifo_lock); + } return err; } @@ -242,7 +251,7 @@ open_hook (struct trivfs_peropen *po) static void close_hook (struct trivfs_peropen *po) { - int was_active, going_away = 0; + int was_active, detach = 0; int flags = po->openmodes; struct pipe *pipe = po->hook; @@ -253,10 +262,10 @@ close_hook (struct trivfs_peropen *po) was_active = (active_fifo == pipe); if (was_active) - { - /* We're the last reader; when we're gone there is no more joy. */ - going_away = ((flags & O_READ) && pipe->readers == 1); - } + /* See if PIPE should cease to be the user-visible face of this fifo. */ + detach = + ((flags & O_READ) && pipe->readers == 1) + || ((flags & O_WRITE) && pipe->writers == 1); else /* Let others have their fun. */ mutex_unlock (&active_fifo_lock); @@ -269,7 +278,7 @@ close_hook (struct trivfs_peropen *po) if (was_active) { - if (going_away) + if (detach) active_fifo = NULL; condition_broadcast (&active_fifo_changed); mutex_unlock (&active_fifo_lock); @@ -305,6 +314,8 @@ trivfs_modify_stat (struct trivfs_protid *cred, struct stat *st) st->st_blocks = st->st_size >> 9; mutex_unlock (&pipe->lock); } + else + st->st_size = st->st_blocks = 0; /* As we try to be clever with large transfers, ask for them. */ st->st_blksize = vm_page_size * 16; @@ -441,7 +452,7 @@ trivfs_S_io_select (struct trivfs_protid *cred, if (!cred) return EOPNOTSUPP; - pipe = cred->hook; + pipe = cred->po->hook; if (*select_type & SELECT_READ) if (cred->po->openmodes & O_READ) @@ -518,7 +529,9 @@ trivfs_S_io_write (struct trivfs_protid *cred, /* ---------------------------------------------------------------- */ error_t -trivfs_S_file_set_size (struct trivfs_protid *cred, off_t size) +trivfs_S_file_set_size (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t reply_type, + off_t size) { return size == 0 ? 0 : EINVAL; } |