4811889e0c
Although we can have multiple readers open because of dup/fork/exec, the current code does not support multiple readers opening a FIFO by explicitly calling 'open'. The main complication in supporting this is that when a blocking reader tries to open and there's already one open, it has to check whether there any writers open. It can't rely on the write_ready event, whose state hasn't changed since the first writer opened. To fix this, add two new named events, check_write_ready_evt and write_ready_ok_evt, and a new method, check_write_ready(). The first event signals the owner's reader thread to call check_write_ready(), which polls the fc_handler list to check for connected writers. If it finds none, it checks to see if there's a writer in the process and then sets/resets write_ready appropriately. When check_write_ready() finishes it sets write_ready_ok_evt to signal the reader that write_ready has been updated. The polling is done via fifo_client_handler::pipe_state(). As long as it's calling that function anyway, check_write_ready() updates the state of each handler. Also add a new lock to prevent a race if two readers are trying to open simultaneously. |
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| ChangeLog | ||
| MAINTAINERS | ||
| Makefile.def | ||
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| README | ||
| README-maintainer-mode | ||
| compile | ||
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| configure | ||
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README
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.