3b4f6217c3
Previously, though readahead buffer handling in pty master was not
fully thread-safe, accept_input() was called from peek_pipe() thread
in select.cc. This caused the problem reported in:
https://cygwin.com/pipermail/cygwin/2023-July/253984.html
The mechanism of the problem is:
1) accept_input() which is called from peek_pipe() thread calls
eat_readahead(-1) before reading readahead buffer. This allows
writing to the readahead buffer from another (main) thread.
2) The main thread calls fhandler_pty_master::write() just after
eat_readahead(-1) was called and before reading the readahead
buffer by accept_input() called from peek_pipe() thread. This
overwrites the readahead buffer.
3) The read result from readahead buffer which was overwritten is
sent to the slave.
This patch makes readahead buffer handling fully thread-safe using
input_mutex to resolve this issue.
Fixes:
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|---|---|---|
| .. | ||
| CVSChangeLogs.old | ||
| cygserver | ||
| cygwin | ||
| doc | ||
| testsuite | ||
| utils | ||
| CONTRIBUTORS | ||
| COPYING | ||
| COPYING.LIB | ||
| CYGWIN_LICENSE | ||
| Makefile.am | ||
| Makefile.am.common | ||
| README | ||
| acinclude.m4 | ||
| autogen.sh | ||
| configure.ac | ||
README
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cygwin documentation is available on the net at https://cygwin.com You might especially be interested in https://cygwin.com/faq/faq.html#faq.programming.building-cygwin