public inbox for cygwin-cvs@sourceware.org
help / color / mirror / Atom feed
* [newlib-cygwin] Cygwin: stat(): Fix "Bad address" error on stat() for /dev/tty.
@ 2023-07-10 8:37 Takashi Yano
0 siblings, 0 replies; only message in thread
From: Takashi Yano @ 2023-07-10 8:37 UTC (permalink / raw)
To: cygwin-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=3edb55af820025013b87fdb53249676067a8b8ee
commit 3edb55af820025013b87fdb53249676067a8b8ee
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date: Fri Jul 7 06:11:52 2023 +0900
Cygwin: stat(): Fix "Bad address" error on stat() for /dev/tty.
As reported in
https://cygwin.com/pipermail/cygwin/2023-June/253888.html,
"Bad address" error occurs when stat() is called after the commit
3721a756b0d8 ("Cygwin: console: Make the console accessible from
other terminals.").
There are two problems in the current code. One is fhandler_console::
fstat() calls get_ttyp()->getsid(). However, fh_alloc() in dtable.cc
omits to initialize the fhandler_console instance when stat() is
called. Due to this, get_ttyp() returns NULL and access violation
occurs. The other problem is fh_alloc() assigns fhandler_console
even if the CTTY is not a console. So the first problem above occurs
even if the CTTY is a pty.
This patch fixes the issue by:
1) Call set_unit() to initialize _tc if the get_ttyp() returns NULL.
2) Assign fhandler_pty_slave for /dev/tty if CTTY is a pty in fh_alloc().
Fixes: 3721a756b0d8 ("Cygwin: console: Make the console accessible
from other terminals.").
Fixes: 23771fa1f7028 ("dtable.cc (fh_alloc): Make different decisions
when generating fhandler for not-opened devices. Add kludge to deal
with opening /dev/tty.")
Reported-by: Bruce Jerrick <bmj001@gmail.com>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
Diff:
---
winsup/cygwin/dtable.cc | 8 +++++++-
winsup/cygwin/fhandler/console.cc | 6 ++++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
index 18e0f3097..2aae2fd65 100644
--- a/winsup/cygwin/dtable.cc
+++ b/winsup/cygwin/dtable.cc
@@ -600,7 +600,13 @@ fh_alloc (path_conv& pc)
case FH_TTY:
if (!pc.isopen ())
{
- fhraw = cnew_no_ctor (fhandler_console, -1);
+ if (CTTY_IS_VALID (myself->ctty))
+ {
+ if (iscons_dev (myself->ctty))
+ fhraw = cnew_no_ctor (fhandler_console, -1);
+ else
+ fhraw = cnew_no_ctor (fhandler_pty_slave, -1);
+ }
debug_printf ("not called from open for /dev/tty");
}
else if (!CTTY_IS_VALID (myself->ctty) && last_tty_dev
diff --git a/winsup/cygwin/fhandler/console.cc b/winsup/cygwin/fhandler/console.cc
index 7768a9941..6aa3b50bf 100644
--- a/winsup/cygwin/fhandler/console.cc
+++ b/winsup/cygwin/fhandler/console.cc
@@ -4554,6 +4554,12 @@ fhandler_console::set_disable_master_thread (bool x, fhandler_console *cons)
int
fhandler_console::fstat (struct stat *st)
{
+ /* When stat() is called, fh_alloc() in dtable.cc omits to initialize
+ the console instance. Due to this, get_ttyp() returns NULL here.
+ So, calling set_unit() is necessary to access getsid(). */
+ if (!get_ttyp ())
+ set_unit ();
+
fhandler_base::fstat (st);
st->st_mode = S_IFCHR | S_IRUSR | S_IWUSR;
pinfo p (get_ttyp ()->getsid ());
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2023-07-10 8:37 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-10 8:37 [newlib-cygwin] Cygwin: stat(): Fix "Bad address" error on stat() for /dev/tty Takashi Yano
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).