Commit Graph

374 Commits

Author SHA1 Message Date
Pedro F. Giffuni
e3043798aa sys/kern: spelling fixes in comments.
No functional change.
2016-04-29 22:15:33 +00:00
Konstantin Belousov
2cd5358a66 Don't clear the software flow control flag before draining for last
close or assert the bug that it is clear when leaving.

Remove an unrelated rotted comment that was attached to the buggy
clearing.

Since draining is not done in more cases, flushing is needed in more
cases, so start fixing flushing:
- do a full flush in ttydisc_close().  State what POSIX requires more
  clearly.  This was missing ttydevsw_pktnotify() calls to tell the
  devsw layer to flush.  Hardware tty drivers don't actually flush
  since they don't understand this API.
- fix 2 missing wakeups in tty_flush().  Most of the wakeups here are
  unnecessary for last close.  But ttydisc_close() did one of the
  missing ones.

This flow control bug ameliorated the design bug of requiring
potentially unbounded waits in draining.  Software flow control is the
easiest way to get an unbounded wait, and a long wait is sometimes
actually useful.  Users can type the xoff character on the receiver
and (if ixon is set on the sender) expect the output to be held until
the user is ready for more.

Hardware flow control can also give the unbounded wait, and this bug
didn't affect hardware flow control.  Unbounded waits from hardware
flow control take a more unusual configuration.  E.g., a terminal
program that controls the modem status lines, or unplugging the cable
in a configuration where this doesn't break the connection.

The design bug is still ameliorated by a newer bug in draining for
last close -- the 1 second timeout.  E.g., if the user types the
xoff character and the sender reaches last close, then output is
not resumed and the wait times out after just 1 second.  This is
broken, but preferable to an unbounded wait.  Before this change,
the output was resumed immediately and usually completed.

Submitted by:	bde
MFC after:	2 weeks
2016-01-26 14:46:39 +00:00
Konstantin Belousov
88d74d64d7 Restore flushing of output for revoke(2) again. Document revoke()'s
intended behaviour in its man page.  Simplify tty_drain() to match.
Don't call ttydevsw methods in tty_flush() if the device is gone
since we now sometimes call it then.

The flushing was supposed to be implemented by passing the FNONBLOCK
flag to VOP_CLOSE() for revoke().  The tty driver is one of the few
that can block in close and was one of the fewer that knew about this.

This almost worked in FreeBSD-1 and similarly in Net/2.  These
versions only almost worked because there was and is considerable
confusion between IO_NDELAY and FNONBLOCK (aka O_NONBLOCK).  IO_NDELAY
is only valid for VOP_READ() and VOP_WRITE().  For other VOPs it has
the same value as O_SHLOCK.  But since vfs_subr.c and tty.c
consistently used the wrong flag and the O_SHLOCK flag is rarely set,
this mostly worked.  It also gave the feature than applications could
get the non-blocking close by abusing O_SHLOCK.

This was first broken then fixed in 1995.  I changed only the tty
driver to use FNONBLOCK, as a hack to get non-blocking via the normal
flag FNONBLOCK for last closes.  I didn't know about revoke()'s use
of IO_NDELAY or change it to be consistent, so revoke() was broken.
Then I changed revoke() to match.

This was next broken in 1997 then fixed in 1998.  Importing Lite2 made
the flags inconsistent again by undoing the fix only in vfs_subr.c.

This was next broken in 2008 by replacing everything in tty.c and not
checking any flags in last close.  Other bugs in draining limited the
resulting unbounded waits to drain in some cases.

It is now possible to fix this better using the new FREVOKE flag.
Just restore flushing for revoke() for now.  Don't restore or undo any
hacks for ordinary last closes yet.  But remove dead code in the
1-second relative timeout (r272789).  This did extra work to extend
the buggy draining for revoke() for as long as possible.  The 1-second
timeout made this not very long by usually flushing after 1 second.

Submitted by:	bde
MFC after:	2 weeks
2016-01-26 07:57:44 +00:00
Marius Strobl
57169cea64 - Make the code consistent with itself style-wise and bring it closer
to style(9).
- Mark unused arguments as such.
- Make the ttystates table const.
2016-01-25 22:58:06 +00:00
Konstantin Belousov
2e77021e4c Don't allow opening the callout device when the callin device is already
open (in disguise as the console device).  The only allowed combination
was supposed to be the callin device with the console.

Fix the assertion in ttydev_close() that was meant to detect this (it
only detected all 3 devices being open).  Assert this in ttydev_open()
too.

Submitted by:	bde
MFC after:	2 weeks
2016-01-25 16:47:20 +00:00
Konstantin Belousov
3593a18a91 Fix the %b flags string for ddb. All bits above the 5th
(TF_OPENED_CONS) were broken in r188147 by adding TF_OPENED_CONS
without updating the string.  It was especially confusing to display
OPENED_CONS as GONE and BYPASS as ZOMBIE.  2 flags at the end were
not updated in r188487.

Don't print an extra 0x prefix for %p in a ddb command.  In the rest
of the kernel there are more than 6000 lines with %p and only about
40 with this bug.

Print a non-extra 0x prefix for %b in a ddb command.  In the rest
of the kernel, there are approx. 180 lines with %b and 2/3 of them
have this bug.

Submitted by:	bde
MFC after:	2 weeks
2016-01-25 15:37:01 +00:00
Konstantin Belousov
fa28b6e7da In tty_dealloc(), clear the queues. See the comment for a scenario
which explains why ttydev_leave() cleanup might not happen.

Submitted by:	bde
MFC after:	3 weeks
2016-01-22 20:38:46 +00:00
Marius Strobl
9750d9e5b6 Fix tty_drain() and, thus, TIOCDRAIN of the current tty(4) incarnation
to actually wait until the TX FIFOs of UARTs have be drained before
returning. This is done by bringing the equivalent of the TS_BUSY flag
found in the previous implementation back in an ABI-preserving way.
Reported and tested by: Patrick Powell

Most likely, drivers for USB-serial-adapters likewise incorporating
TX FIFOs as well as other terminal devices that buffer output in some
form should also provide implementations of tsw_busy.

MFC after:	3 days
2016-01-19 23:34:27 +00:00
Konstantin Belousov
0de1455462 Convert tty common code to use make_dev_s().
Tty.c was untypical in that it handled the si_drv1 issue consistently
and correctly, by always checking for si_drv1 being non-NULL and
sleeping if NULL.  The removed code also illustrated unneeded
complications in drivers which are eliminated by the use of new KPI.

Reviewed by:	hps, jhb
Discussed with:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
Differential revision:	https://reviews.freebsd.org/D4746
2016-01-07 20:15:09 +00:00
Mateusz Guzik
b7a39e9e07 filedesc: simplify fget_unlocked & friends
Introduce fget_fcntl which performs appropriate checks when needed.
This removes a branch from fget_unlocked.

Introduce fget_mmap dealing with cap_rights_to_vmprot conversion.
This removes a branch from _fget.

Modify fget_unlocked to pass sequence counter to interested callers so
that they can perform their own checks and make sure the result was
otained from stable & current state.

Reviewed by:	silence on -hackers
2015-02-17 23:54:06 +00:00
Marcel Moolenaar
383f423be1 Fix draining in ttydev_leave():
1.  ERESTART is not only returned when the revoke count changed. It
    is also returned when a signal is received. While a change in
    the revoke count should be ignored, a signal should not.
2.  Waiting until the output queue is entirely drained can cause a
    hang when the underlying device is stuck or broken.

Have tty_drain() take care of this by telling it when we're leaving.
When leaving, tty_drain() will use a timed wait to address point 2
above and it will check the revoke count to handle point 1 above.
The timeout is set to 1 second, which is arbitrary and long enough
to expect a change in the output queue.

Discussed with: jilles@
Reported by: Yamagi Burmeister <lists@yamagi.org>
2014-10-09 02:30:38 +00:00
Marcel Moolenaar
75c2b79df8 Apply r269126 to tty_timedwait():
Don't return ERESTART when the device is gone.
2014-10-09 01:59:25 +00:00
Neel Natu
fbe602fb61 tty_rel_free() can be called more than once for the same tty so make sure
that the tty is dequeued from 'tty_list' only the first time.

The panic below was seen when a revoke(2) was issued on an nmdm device.
In this case there was also a thread that was blocked on a read(2) on the
device. The revoke(2) woke up the blocked thread which would typically
return an error to userspace. In this case the reader also held the last
reference on the file descriptor so fdrop() ended up calling tty_rel_free()
via ttydev_close().

tty_rel_free() then tried to dequeue 'tp' again which led to the panic.

panic: Bad link elm 0xfffff80042602400 prev->next != elm
cpuid = 1
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00f9c90460
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe00f9c90510
vpanic() at vpanic+0x189/frame 0xfffffe00f9c90590
panic() at panic+0x43/frame 0xfffffe00f9c905f0
tty_rel_free() at tty_rel_free+0x29b/frame 0xfffffe00f9c90640
ttydev_close() at ttydev_close+0x1f9/frame 0xfffffe00f9c90690
devfs_close() at devfs_close+0x298/frame 0xfffffe00f9c90720
VOP_CLOSE_APV() at VOP_CLOSE_APV+0x13c/frame 0xfffffe00f9c90770
vn_close() at vn_close+0x194/frame 0xfffffe00f9c90810
vn_closefile() at vn_closefile+0x48/frame 0xfffffe00f9c90890
devfs_close_f() at devfs_close_f+0x2c/frame 0xfffffe00f9c908c0
_fdrop() at _fdrop+0x29/frame 0xfffffe00f9c908e0
sys_read() at sys_read+0x63/frame 0xfffffe00f9c90980
amd64_syscall() at amd64_syscall+0x2b3/frame 0xfffffe00f9c90ab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe00f9c90ab0
--- syscall (3, FreeBSD ELF64, sys_read), rip = 0x800b78d8a, rsp = 0x7fffffbfdaf8, rbp = 0x7fffffbfdb30 ---

CR:		https://reviews.freebsd.org/D851
Reviewed by:	glebius, ed
Reported by:	Leon Dang
Sponsored by:	Nahanni Systems
MFC after:	1 week
2014-09-28 21:12:23 +00:00
Marcel Moolenaar
be836fab6c Don't return ERESTART when the device is gone. In ttydev_leave() ERESTART
is the indication that draining got interrupted due to a revoke(2) and
that tty_drain() is to be called again for draining to complete. If the
device is flagged as gone, then waiting/draining is not possible. Only
return ERESTART when waiting is still possible.

Obtained from:	Juniper Networks, Inc.
2014-07-26 15:46:41 +00:00
Robert Watson
4a14441044 Update kernel inclusions of capability.h to use capsicum.h instead; some
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.

MFC after:	3 weeks
2014-03-16 10:55:57 +00:00
Gleb Smirnoff
7276319825 Move list of ttys handling from the allocating procedures, to the
device creation stage. A device creation can fail, and in that case
an entry already on the list will be freed.

Sponsored by:	Nginx, Inc.
2013-12-20 19:45:51 +00:00
Gleb Smirnoff
e1e585a87c - Rename tty_makedev() into tty_makedevf() and make it capable
to fail and return error.
- Use make_dev_p() in tty_makedevf() instead of make_dev_cred().
- Always pass MAKEDEV_CHECKNAME flag.
- Optionally pass MAKEDEV_REF flag.
- Provide macro for compatibility with old API.

This fixes races with simultaneous creation and desctruction of
ttys, and makes it possible to call tty_makedevf() from device
cloners.

A race in tty_watermarks() still exist, since the latter drops
lock for M_WAITOK allocation. This will be addressed in separate
commit.

Reviewed by:	kib
Sponsored by:	Nginx, Inc.
2013-12-18 12:50:43 +00:00
Marcel Moolenaar
15773775f7 Properly drain the TTY when both revoke(2) and close(2) end up closing
the TTY. In such a case, ttydev_close() is called multiple times and
each time, t_revokecnt is incremented and cv_broadcast() is called for
both the t_outwait and t_inwait condition variables.
Let's say revoke(2) comes in first and gets to call tty_drain() from
ttydev_leave(). Let's say that the revoke comes from init(8) as the
result of running "shutdown -r now". Since shutdown prints various
messages to the console before announing that the machine will reboot
immediately, let's also say that the output queue is not empty and
that tty_drain() has something to do. Let's assume this all happens
on a 9600 baud serial console, so it takes a time to drain.
The shutdown command will exit(2) and as such will end up closing
stdout. Let's say this close will come in second, bump t_revokecnt
and call tty_wakeup(). This has tty_wait() return prematurely and
the next thing that will happen is that the thread doing revoke(2)
will flush the TTY. Since the drain wasn't complete, the flush will
effectively drop whatever is left in t_outq.

This change takes into account that tty_drain() will return ERESTART
due to the fact that t_revokecnt was bumped and in that case simply
call tty_drain() again. The thread in question is already performing
the close so it can safely finish draining the TTY before destroying
the TTY structure.

Now all messages from shutdown will be printed on the serial console.

Obtained from:	Juniper Networks, Inc.
2013-12-16 00:50:14 +00:00
Pawel Jakub Dawidek
7008be5bd7 Change the cap_rights_t type from uint64_t to a structure that we can extend
in the future in a backward compatible (API and ABI) way.

The cap_rights_t represents capability rights. We used to use one bit to
represent one right, but we are running out of spare bits. Currently the new
structure provides place for 114 rights (so 50 more than the previous
cap_rights_t), but it is possible to grow the structure to hold at least 285
rights, although we can make it even larger if 285 rights won't be enough.

The structure definition looks like this:

	struct cap_rights {
		uint64_t	cr_rights[CAP_RIGHTS_VERSION + 2];
	};

The initial CAP_RIGHTS_VERSION is 0.

The top two bits in the first element of the cr_rights[] array contain total
number of elements in the array - 2. This means if those two bits are equal to
0, we have 2 array elements.

The top two bits in all remaining array elements should be 0.
The next five bits in all array elements contain array index. Only one bit is
used and bit position in this five-bits range defines array index. This means
there can be at most five array elements in the future.

To define new right the CAPRIGHT() macro must be used. The macro takes two
arguments - an array index and a bit to set, eg.

	#define	CAP_PDKILL	CAPRIGHT(1, 0x0000000000000800ULL)

We still support aliases that combine few rights, but the rights have to belong
to the same array element, eg:

	#define	CAP_LOOKUP	CAPRIGHT(0, 0x0000000000000400ULL)
	#define	CAP_FCHMOD	CAPRIGHT(0, 0x0000000000002000ULL)

	#define	CAP_FCHMODAT	(CAP_FCHMOD | CAP_LOOKUP)

There is new API to manage the new cap_rights_t structure:

	cap_rights_t *cap_rights_init(cap_rights_t *rights, ...);
	void cap_rights_set(cap_rights_t *rights, ...);
	void cap_rights_clear(cap_rights_t *rights, ...);
	bool cap_rights_is_set(const cap_rights_t *rights, ...);

	bool cap_rights_is_valid(const cap_rights_t *rights);
	void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src);
	void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src);
	bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little);

Capability rights to the cap_rights_init(), cap_rights_set(),
cap_rights_clear() and cap_rights_is_set() functions are provided by
separating them with commas, eg:

	cap_rights_t rights;

	cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT);

There is no need to terminate the list of rights, as those functions are
actually macros that take care of the termination, eg:

	#define	cap_rights_set(rights, ...)				\
		__cap_rights_set((rights), __VA_ARGS__, 0ULL)
	void __cap_rights_set(cap_rights_t *rights, ...);

Thanks to using one bit as an array index we can assert in those functions that
there are no two rights belonging to different array elements provided
together. For example this is illegal and will be detected, because CAP_LOOKUP
belongs to element 0 and CAP_PDKILL to element 1:

	cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL);

Providing several rights that belongs to the same array's element this way is
correct, but is not advised. It should only be used for aliases definition.

This commit also breaks compatibility with some existing Capsicum system calls,
but I see no other way to do that. This should be fine as Capsicum is still
experimental and this change is not going to 9.x.

Sponsored by:	The FreeBSD Foundation
2013-09-05 00:09:56 +00:00
Pawel Jakub Dawidek
2609222ab4 Merge Capsicum overhaul:
- Capability is no longer separate descriptor type. Now every descriptor
  has set of its own capability rights.

- The cap_new(2) system call is left, but it is no longer documented and
  should not be used in new code.

- The new syscall cap_rights_limit(2) should be used instead of
  cap_new(2), which limits capability rights of the given descriptor
  without creating a new one.

- The cap_getrights(2) syscall is renamed to cap_rights_get(2).

- If CAP_IOCTL capability right is present we can further reduce allowed
  ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
  ioctls can be retrived with cap_ioctls_get(2) syscall.

- If CAP_FCNTL capability right is present we can further reduce fcntls
  that can be used with the new cap_fcntls_limit(2) syscall and retrive
  them with cap_fcntls_get(2).

- To support ioctl and fcntl white-listing the filedesc structure was
  heavly modified.

- The audit subsystem, kdump and procstat tools were updated to
  recognize new syscalls.

- Capability rights were revised and eventhough I tried hard to provide
  backward API and ABI compatibility there are some incompatible changes
  that are described in detail below:

	CAP_CREATE old behaviour:
	- Allow for openat(2)+O_CREAT.
	- Allow for linkat(2).
	- Allow for symlinkat(2).
	CAP_CREATE new behaviour:
	- Allow for openat(2)+O_CREAT.

	Added CAP_LINKAT:
	- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
	- Allow to be target for renameat(2).

	Added CAP_SYMLINKAT:
	- Allow for symlinkat(2).

	Removed CAP_DELETE. Old behaviour:
	- Allow for unlinkat(2) when removing non-directory object.
	- Allow to be source for renameat(2).

	Removed CAP_RMDIR. Old behaviour:
	- Allow for unlinkat(2) when removing directory.

	Added CAP_RENAMEAT:
	- Required for source directory for the renameat(2) syscall.

	Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
	- Allow for unlinkat(2) on any object.
	- Required if target of renameat(2) exists and will be removed by this
	  call.

	Removed CAP_MAPEXEC.

	CAP_MMAP old behaviour:
	- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
	  PROT_WRITE.
	CAP_MMAP new behaviour:
	- Allow for mmap(2)+PROT_NONE.

	Added CAP_MMAP_R:
	- Allow for mmap(PROT_READ).
	Added CAP_MMAP_W:
	- Allow for mmap(PROT_WRITE).
	Added CAP_MMAP_X:
	- Allow for mmap(PROT_EXEC).
	Added CAP_MMAP_RW:
	- Allow for mmap(PROT_READ | PROT_WRITE).
	Added CAP_MMAP_RX:
	- Allow for mmap(PROT_READ | PROT_EXEC).
	Added CAP_MMAP_WX:
	- Allow for mmap(PROT_WRITE | PROT_EXEC).
	Added CAP_MMAP_RWX:
	- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).

	Renamed CAP_MKDIR to CAP_MKDIRAT.
	Renamed CAP_MKFIFO to CAP_MKFIFOAT.
	Renamed CAP_MKNODE to CAP_MKNODEAT.

	CAP_READ old behaviour:
	- Allow pread(2).
	- Disallow read(2), readv(2) (if there is no CAP_SEEK).
	CAP_READ new behaviour:
	- Allow read(2), readv(2).
	- Disallow pread(2) (CAP_SEEK was also required).

	CAP_WRITE old behaviour:
	- Allow pwrite(2).
	- Disallow write(2), writev(2) (if there is no CAP_SEEK).
	CAP_WRITE new behaviour:
	- Allow write(2), writev(2).
	- Disallow pwrite(2) (CAP_SEEK was also required).

	Added convinient defines:

	#define	CAP_PREAD		(CAP_SEEK | CAP_READ)
	#define	CAP_PWRITE		(CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_R		(CAP_MMAP | CAP_SEEK | CAP_READ)
	#define	CAP_MMAP_W		(CAP_MMAP | CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_X		(CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
	#define	CAP_MMAP_RW		(CAP_MMAP_R | CAP_MMAP_W)
	#define	CAP_MMAP_RX		(CAP_MMAP_R | CAP_MMAP_X)
	#define	CAP_MMAP_WX		(CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_MMAP_RWX		(CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_RECV		CAP_READ
	#define	CAP_SEND		CAP_WRITE

	#define	CAP_SOCK_CLIENT \
		(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
		 CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
	#define	CAP_SOCK_SERVER \
		(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
		 CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
		 CAP_SETSOCKOPT | CAP_SHUTDOWN)

	Added defines for backward API compatibility:

	#define	CAP_MAPEXEC		CAP_MMAP_X
	#define	CAP_DELETE		CAP_UNLINKAT
	#define	CAP_MKDIR		CAP_MKDIRAT
	#define	CAP_RMDIR		CAP_UNLINKAT
	#define	CAP_MKFIFO		CAP_MKFIFOAT
	#define	CAP_MKNOD		CAP_MKNODAT
	#define	CAP_SOCK_ALL		(CAP_SOCK_CLIENT | CAP_SOCK_SERVER)

Sponsored by:	The FreeBSD Foundation
Reviewed by:	Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with:	rwatson, benl, jonathan
ABI compatibility discussed with:	kib
2013-03-02 00:53:12 +00:00
Kevin Lo
0f5e7edc14 Fix typo; s/ouput/output 2012-11-07 07:00:59 +00:00
Ed Schouten
305921c48e Add tty_set_winsize().
This removes some of the signalling magic from the Syscons driver and
puts it in the TTY layer, where it belongs.
2012-11-03 22:21:37 +00:00
Ed Schouten
1da7bb41ed Correct SIGTTIN handling.
In the old TTY layer, SIGTTIN was correctly handled like this:

	while (data should be read) {
		send SIGTTIN if not foreground process group
		read data
	}

In the new TTY layer, however, this behaviour was changed, based on a
false interpretation of the standard:

	send SIGTTIN if not foreground process group
	while (data should be read) {
		read data
	}

Correct this by pushing tty_wait_background() into the ttydisc_read_*()
functions.

Reported by:	koitsu
PR:		kern/173010
MFC after:	2 weeks
2012-10-25 09:05:21 +00:00
Peter Holm
e84a11e7ff In tty_makedev() the following construction:
dev = make_dev_cred();
dev->si_drv1 = tp;

leaves a small window where the newly created device may be opened
and si_drv1 is NULL.

As this is a vary rare situation, using a lock to close the window
seems overkill. Instead just wait for the assignment of si_drv1.

Suggested by:	kib
MFC after:	1 week
2012-06-18 07:34:38 +00:00
Pawel Jakub Dawidek
d3644b04ca Eliminate redundant variable.
Sponsored by:	FreeBSD Foundation
MFC after:	1 week
2012-06-07 23:08:18 +00:00
Pawel Jakub Dawidek
f6ed2ff79d Plug file reference leak in capability failure case.
Sponsored by:	FreeBSD Foundation
MFC after:	3 days
2012-06-07 22:49:09 +00:00
Poul-Henning Kamp
f9a61f7dcb Also call the low-level driver if ->c_iflag & (IXON|IXOFF|IXANY) changes.
Uftdi(4) examines (c_iflag & (IXON|IXOFF)) to control hw XON-XOFF support.
This is obviously no good, if changes to those bits are not communicated
down the stack.
2012-02-26 20:56:49 +00:00
Ed Schouten
cd864a19a5 Fix whitespace inconsistencies in TTY code. 2012-02-06 18:15:46 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Ed Schouten
ca0856d3d1 Fix error return codes for ioctls on init/lock state devices.
In revision 223722 we introduced support for driver ioctls on init/lock
state devices. Unfortunately the call to ttydevsw_cioctl() clobbers the
value of the error variable, meaning that in many cases ioctl() will now
return ENOTTY, even though the ioctl() was processed properly.

Reported by:	Boris Samorodov <bsam ipt ru>
Patch by:	jilles@
Approved by:	re@ (kib@)
2011-09-12 10:07:21 +00:00
Attilio Rao
6aba400a70 Fix a deficiency in the selinfo interface:
If a selinfo object is recorded (via selrecord()) and then it is
quickly destroyed, with the waiters missing the opportunity to awake,
at the next iteration they will find the selinfo object destroyed,
causing a PF#.

That happens because the selinfo interface has no way to drain the
waiters before to destroy the registered selinfo object. Also this
race is quite rare to get in practice, because it would require a
selrecord(), a poll request by another thread and a quick destruction
of the selrecord()'ed selinfo object.

Fix this by adding the seldrain() routine which should be called
before to destroy the selinfo objects (in order to avoid such case),
and fix the present cases where it might have already been called.
Sometimes, the context is safe enough to prevent this type of race,
like it happens in device drivers which installs selinfo objects on
poll callbacks. There, the destruction of the selinfo object happens
at driver detach time, when all the filedescriptors should be already
closed, thus there cannot be a race.
For this case, mfi(4) device driver can be set as an example, as it
implements a full correct logic for preventing this from happening.

Sponsored by:	Sandvine Incorporated
Reported by:	rstone
Tested by:	pluknet
Reviewed by:	jhb, kib
Approved by:	re (bz)
MFC after:	3 weeks
2011-08-25 15:51:54 +00:00
Robert Watson
a9d2f8d84f Second-to-last commit implementing Capsicum capabilities in the FreeBSD
kernel for FreeBSD 9.0:

Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *.  With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.

Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.

In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.

Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.

Approved by:	re (bz)
Submitted by:	jonathan
Sponsored by:	Google Inc
2011-08-11 12:30:23 +00:00
Ed Schouten
18f5477167 Reintroduce the cioctl() hook in the TTY layer for digi(4).
The cioctl() hook can be used by drivers to add ioctls to the *.init and
*.lock devices. This commit breaks the ttydevsw ABI, since this
structure didn't provide any padding. To prevent ABI breakage in the
future, add a tsw_spare.

Submitted by:	Peter Jeremy <peter jeremy alcatel lucent com>
Obtained from:	kern/152254 (slightly modified)
2011-07-02 13:54:20 +00:00
Ed Schouten
7c9669276e Fix whitespace inconsistencies in the TTY layer and its drivers owned by me. 2011-06-26 18:26:20 +00:00
Konstantin Belousov
23b70c1ae2 Finish r210923, 210926. Mark some devices as eternal.
MFC after:	2 weeks
2011-01-04 10:59:38 +00:00
Ed Schouten
d1817ed7f3 Just make callout devices and /dev/console force CLOCAL on open().
Instead of adding custom checks to wait for DCD on open(), just modify
the termios structure to set CLOCAL. This means SIGHUP is no longer
generated when losing DCD as well.

Reviewed by:	kib@
MFC after:	1 week
2010-09-19 16:35:42 +00:00
Ed Schouten
4b5d5046ab Ignore DCD handling on /dev/console entirely.
This makes /dev/console more fail-safe and prevents a potential console
lock-up during boot.

Discussed on:	stable@
Tested by:	koitsu@
MFC after:	1 week
2010-09-19 14:21:39 +00:00
Konstantin Belousov
3979450b4c Add new make_dev_p(9) flag MAKEDEV_ETERNAL to inform devfs that created
cdev will never be destroyed. Propagate the flag to devfs vnodes as
VV_ETERNVALDEV. Use the flags to avoid acquiring devmtx and taking a
thread reference on such nodes.

In collaboration with:	pho
MFC after:	1 month
2010-08-06 09:42:15 +00:00
Ed Schouten
822eb2b050 Fix a race condition, where a TTY could be destroyed twice.
There are special cases where tty_rel_free() can be called twice in a
row, namely when closing and revoking the TTY at the same moment. Only
call destroy_dev_sched_cb() once.

Reported by:	Jeremie Le Hen
MFC after:	1 week
2010-07-06 08:56:34 +00:00
Ed Schouten
328d9d2c96 Make TIOCSTI work again.
It looks like I didn't implement this when I imported MPSAFE TTY.
Applications like mail(1) still use this. I think it's conceptually bad.

Tested by:	Pete French <petefrench ticketswitch com>
MFC after:	2 weeks
2010-01-04 20:59:52 +00:00
Robert Noland
cfd7bacef2 Update d_mmap() to accept vm_ooffset_t and vm_memattr_t.
This replaces d_mmap() with the d_mmap2() implementation and also
changes the type of offset to vm_ooffset_t.

Purge d_mmap2().

All driver modules will need to be rebuilt since D_VERSION is also
bumped.

Reviewed by:	jhb@
MFC after:	Not in this lifetime...
2009-12-29 21:51:28 +00:00
Ed Schouten
6eaf04022b Don't allocate an input buffer for a TTY when the receiver is turned off.
When the termios CREAD flag is not set, it makes little sense to
allocate an input buffer. Just set the size to 0 in this case to reduce
memory footprint.

Disallow CREAD to be disabled for pseudo-devices to prevent
foot-shooting.
2009-12-01 19:14:57 +00:00
Konstantin Belousov
a3de221dbe Among signal generation syscalls, only sigqueue(2) is allowed by POSIX
to fail due to lack of resources to queue siginfo. Add KSI_SIGQ flag
that allows sigqueue_add() to fail while trying to allocate memory for
new siginfo. When the flag is not set, behaviour is the same as for
KSI_TRAP: if memory cannot be allocated, set bit in sq_kill. KSI_TRAP is
kept to preserve KBI.

Add SI_KERNEL si_code, to be used in siginfo.si_code when signal is
generated by kernel. Deliver siginfo when signal is generated by kill(2)
family of syscalls (SI_USER with properly filled si_uid and si_pid), or
by kernel (SI_KERNEL, mostly job control or SIGIO). Since KSI_SIGQ flag
is not set for the ksi, low memory condition cause old behaviour.

Keep psignal(9) KBI intact, but modify it to generate SI_KERNEL
si_code. Pgsignal(9) and gsignal(9) now take ksi explicitely. Add
pksignal(9) that behaves like psignal but takes ksi, and ddb kill
command implemented as pksignal(..., ksi = NULL) to not do allocation
while in debugger.

While there, remove some register specifiers and use ANSI C prototypes.

Reviewed by:	davidxu
MFC after:	1 month
2009-11-17 11:39:15 +00:00
Ed Schouten
6015f6f35a Properly set the low watermarks when reducing the baud rate.
Now that buffers are deallocated lazily, we should not use
tty*q_getsize() to obtain the buffer size to calculate the low
watermarks. Doing this may cause the watermark to be placed outside the
typical buffer size.

This caused some regressions after my previous commit to the TTY code,
which allows pseudo-devices to resize the buffers as well.

Reported by:	yongari, dougb
MFC after:	1 week
2009-10-19 07:17:37 +00:00
Ed Schouten
5ed8d12443 Allow the buffer size to be configured for pseudo-like TTY devices.
Devices that don't implement param() (which means they don't support
hardware parameters such as flow control, baud rate) hardcode the baud
rate to TTYDEF_SPEED. This means the buffer size cannot be configured,
which is a little inconvenient when using canonical mode with big lines
of input, etc.

Make it adjustable, but do clamp it between B50 and B115200 to prevent
awkward buffer sizes. Remove the baud rate assignment from
/etc/gettytab. Trust the kernel to fill in a proper value.

Reported by:	Mikolaj Golub <to my trociny gmail com>
MFC after:	1 month
2009-10-18 19:48:53 +00:00
Ed Schouten
99087885be Make lock devices work properly.
It turned out I did add the code to use the init state devices to set
the termios structure when opening the device, but it seems I totally
forgot to add the bits required to force the actual locking of flags
through the lock state devices.

Reported by:	ru
MFC after:	1 week (to be discussed)
2009-10-18 19:45:44 +00:00
Robert Watson
e76d823b81 Use C99 initialization for struct filterops.
Obtained from:	Mac OS X
Sponsored by:	Apple Inc.
MFC after:	3 weeks
2009-09-12 20:03:45 +00:00
Ed Schouten
6b53d5c0e7 Fix regressions in return events of poll() on TTYs.
As pointed out, POLLHUP should be generated, even if it hasn't been
specified on input. It is also not allowed to return both POLLOUT and
POLLHUP at the same time.

Reported by:	jilles
Approved by:	re (kib)
2009-07-08 10:21:52 +00:00
Ed Schouten
f9bb1cf010 Add FIONWRITE support to TTYs.
TTYs already supported TIOCOUTQ, but FIONWRITE seems to be a more
generic name for this.

Approved by:	re (kib)
2009-06-28 12:02:15 +00:00
Ed Schouten
9801591468 Improve my last commit: use a separate condvar to serialize.
The advantage of using a separate condvar is that we can just use
cv_signal(9) instead of cv_broadcast(9). It makes no sense to wake up
multiple threads. It also makes the TTY code easier to understand.
t_dcdwait sounds totally unrelated.
2009-06-23 21:43:02 +00:00