Commit graph

93 commits

Author SHA1 Message Date
Lionel Sambuc
7031438f58 Message type and related cleanup
- Intorduce and use a message type for VFS_GETDENTS, VFS_READ,
   VFS_WRITE.

 - Some cleanup to related functions where vir_bytes are replaced (and
   casted to/from, in parameter definition and local variables as well.

   This allow to see more clearly which function receives unsafe
   (pointer) values, or at least values which are not supposed to be
   valid in the address space of VFS. The current patch does so only
   for the minimal amount of functions which are concerned with the
   introduction of the new message type.

Change-Id: I0cdca97409c4016d02fae067b48bf55d37572c5c
2014-07-28 17:05:34 +02:00
Ben Gras
565f13088f make vfs & filesystems use failable copying
Change the kernel to add features to vircopy and safecopies so that
transparent copy fixing won't happen to avoid deadlocks, and such copies
fail with EFAULT.

Transparently making copying work from filesystems (as normally done by
the kernel & VM when copying fails because of missing/readonly memory)
is problematic as it can happen that, for file-mapped ranges, that that
same filesystem that is blocked on the copy request is needed to satisfy
the memory range, leading to deadlock. Dito for VFS itself, if done with
a blocking call.

This change makes the copying done from a filesystem fail in such cases
with EFAULT by VFS adding the CPF_TRY flag to the grants. If a FS call
fails with EFAULT, VFS will then request the range to be made available
to VM after the FS is unblocked, allowing it to be used to satisfy the
range if need be in another VFS thread.

Similarly, for datacopies that VFS itself does, it uses the failable
vircopy variant and callers use a wrapper that talk to VM if necessary
to get the copy to work.

	. kernel: add CPF_TRY flag to safecopies
	. kernel: only request writable ranges to VM for the
	  target buffer when copying fails
	. do copying in VFS TRY-first
	. some fixes in VM to build SANITYCHECK mode
	. add regression test for the cases where
	  - a FS system call needs memory mapped in a process that the
	    FS itself must map.
	  - such a range covers more than one file-mapped region.
	. add 'try' mode to vircopy, physcopy
	. add flags field to copy kernel call messages
	. if CP_FLAG_TRY is set, do not transparently try
	  to fix memory ranges
	. for use by VFS when accessing user buffers to avoid
	  deadlock
	. remove some obsolete backwards compatability assignments
        . VFS: let thread scheduling work for VM requests too
          Allows VFS to make calls to VM while suspending and resuming
          the currently running thread. Does currently not work for the
          main thread.
        . VM: add fix memory range call for use by VFS

Change-Id: I295794269cea51a3163519a9cfe5901301d90b32
2014-07-28 17:05:14 +02:00
David van Moolenbroek
24ec0d73b5 Clean up interface to PM and VFS
- introduce new call numbers, names, and field aliases;
- initialize request messages to zero for all ABI calls;
- format callnr.h in the same way as com.h;
- redo call tables in both servers;
- remove param.h namespace pollution in the servers;
- make brk(2) go to VM directly, rather than through PM;
- remove obsolete BRK, UTIME, and WAIT calls;
- clean up path copying routine in VFS;
- move remaining system calls from libminlib to libc;
- correct some errno-related mistakes in libc routines.

Change-Id: I2d8ec5d061cd7e0b30c51ffd77aa72ebf84e2565
2014-03-01 09:05:01 +01:00
David van Moolenbroek
2c8310fce6 VFS: store m_out as part of worker thread state
There is no need to pass pointers around when there is a structure
available that already stores other similar state, such as m_in.

Change-Id: I3164c5c55c71f443688103d1f0756c086eb05974
2014-03-01 09:05:00 +01:00
David van Moolenbroek
44d3230e40 For common calls, give servers unique call numbers
The getsysinfo(2), getrusage(2), and svrctl(2) calls used the same
call number to different services. Since we want to give each service
its own call number ranges, this is no longer tenable. This patch
introduces per-service call numbers for these calls.

Note that the remainder of the COMMON_ range is left intact, as these
the remaining requests in it are processed by SEF and thus server-
agnostic. The range should really be prefixed with SEF_ now.

Change-Id: I80d728bbeb98227359c525494c433965b40fefc3
2014-03-01 09:05:00 +01:00
David van Moolenbroek
664b726cd3 VFS: further cleanup of device code
- all TTY-related exceptions have now been merged into the regular
  code paths, allowing non-TTY drivers to expose TTY-like devices;
- as part of this, CTTY_MAJOR is now fully managed by VFS instead of
  being an ugly stepchild of the TTY driver;
- device styles have become completely obsolete, support for them has
  been removed throughout the system; same for device flags, which had
  already become useless a while ago;
- device map open/close and I/O function pointers have lost their use,
  thus finally making the VFS device code actually readable;
- the device-unrelated pm_setsid has been moved to misc.c;
- some other small cleanup-related changes.

Change-Id: If90b10d1818e98a12139da3e94a15d250c9933da
2014-03-01 09:04:58 +01:00
David van Moolenbroek
e5cc85fdc4 Extend dupfrom(2) into copyfd(2)
This single function allows copying file descriptors from and to
processes, and closing a previously copied remote file descriptor.
This function replaces the five FD-related UDS backcalls. While it
limits the total number of in-flight file descriptors to OPEN_MAX,
this change greatly improves crash recovery support of UDS, since all
in-flight file descriptors will be closed instead of keeping them
open indefinitely (causing VFS to crash on system shutdown). With the
new copyfd call, UDS becomes simpler, and the concept of filps is no
longer exposed outside of VFS.

This patch also moves the checkperms(2) stub into libminlib, thus
fully abstracting away message details of VFS communication from UDS.

Change-Id: Idd32ad390a566143c8ef66955e5ae2c221cff966
2014-03-01 09:04:58 +01:00
Lionel Sambuc
9fab85c2de Replacing timer_t by netbsd's timer_t
* Renamed struct timer to struct minix_timer
 * Renamed timer_t to minix_timer_t
 * Ensured all the code uses the minix_timer_t typedef
 * Removed ifdef around _BSD_TIMER_T
 * Removed include/timers.h and merged it into include/minix/timers.h
 * Resolved prototype conflict by renaming kernel's (re)set_timer
   to (re)set_kernel_timer.

Change-Id: I56f0f30dfed96e1a0575d92492294cf9a06468a5
2014-03-01 09:04:54 +01:00
David van Moolenbroek
dba2d1f8b4 VFS: add dupfrom(2) call
This call copies a file descriptor from a remote process into the
calling process. The call is for the VND driver only, and in the
future, ACLs will prevent any other process from using this call.

Change-Id: Ib16fdd1f1a12cb38a70d7e441dad91bc86898f6d
2014-03-01 09:04:54 +01:00
David van Moolenbroek
665198b4c2 Rewrite character driver protocol
As a side effect, remove the clone style, as the normal device style
supports device cloning now.

Change-Id: Ie82d1ef0385514a04a8faa139129a617895780b5
2014-03-01 09:04:52 +01:00
David van Moolenbroek
87337273e4 Remove support for reopening character devices
Previously, VFS would reopen a character device after a driver crash
if the associated file descriptor was opened with the O_REOPEN flag.
This patch removes support for this feature. The code was complex,
full of uncovered corner cases, and hard to test. Moreover, it did not
actually hide the crash from user applications: they would get an
error code to indicate that something went wrong, and have to decide
based on the nature of the underlying device how to continue.

- remove support for O_REOPEN, and make playwave(1) reopen its device;
- remove support for the DEV_REOPEN protocol message;
- remove all code in VFS related to reopening character devices;
- no longer change VFS filp reference count and FD bitmap upon filp
  invalidation; instead, make get_filp* fail all calls on invalidated
  FDs except when obtained with the locktype VNODE_OPCL which is used
  by close_fd only;
- remove the VFS fproc file descriptor bitmap entirely, returning to
  the situation that a FD is in use if its slot points to a filp; use
  FILP_CLOSED as single means of marking a filp as invalidated.

Change-Id: I34f6bc69a036b3a8fc667c1f80435ff3af56558f
2014-03-01 09:04:52 +01:00
David van Moolenbroek
a4277506a2 VFS: rework device code
- block the calling thread on character device close;
- fully separate block and character open/close routines;
- reuse generic open/close code for the cloning case;
- zero all messages to drivers before filling them;
- use appropriate types for major/minor device numbers.

Change-Id: Ia90e6fe5688f212f835c5ee1bfca831cb249cf51
2014-03-01 09:04:52 +01:00
David van Moolenbroek
f6915d3dee Make PFS backcalls regular VFS calls
- prefix them with VFS_ as they are going to VFS;
- give these calls normal call numbers;
- give them their own set of message field aliases;
- also make do_mapdriver a regular call.

Change-Id: I2140439f288b06d699a1f65438bd8306509b259e
2014-03-01 09:04:52 +01:00
David van Moolenbroek
723e51327f VFS: worker thread model overhaul
The main purpose of this patch is to fix handling of unpause calls
from PM while another call is ongoing. The solution to this problem
sparked a full revision of the threading model, consisting of a large
number of related changes:

- all active worker threads are now always associated with a process,
  and every process has at most one active thread working for it;
- the process lock is always held by a process's worker thread;
- a process can now have both normal work and postponed PM work
  associated to it;
- timer expiry and non-postponed PM work is done from the main thread;
- filp garbage collection is done from a thread associated with VFS;
- reboot calls from PM are now done from a thread associated with PM;
- the DS events handler is protected from starting multiple threads;
- support for a system worker thread has been removed;
- the deadlock recovery thread has been replaced by a parameter to the
  worker_start() function; the number of worker threads has
  consequently been increased by one;
- saving and restoring of global but per-thread variables is now
  centralized in worker_suspend() and worker_resume(); err_code is now
  saved and restored in all cases;
- the concept of jobs has been removed, and job_m_in now points to a
  message stored in the worker thread structure instead;
- the PM lock has been removed;
- the separate exec lock has been replaced by a lock on the VM
  process, which was already being locked for exec calls anyway;
- PM_UNPAUSE is now processed as a postponed PM request, from a thread
  associated with the target process;
- the FP_DROP_WORK flag has been removed, since it is no longer more
  than just an optimization and only applied to processes operating on
  a pipe when getting killed;
- assignment to "fp" now takes place only when obtaining new work in
  the main thread or a worker thread, when resuming execution of a
  thread, and in the special case of exiting processes during reboot;
- there are no longer special cases where the yield() call is used to
  force a thread to run.

Change-Id: I7a97b9b95c2450454a9b5318dfa0e6150d4e6858
2014-02-18 11:25:03 +01:00
David van Moolenbroek
f707937192 VFS: process char driver replies from main thread
Previously, processing of some replies coming from character drivers
could block on locks, and therefore, such processing was done from
threads that were associated to the character driver process. The
hidden consequence of this was that if all threads were in use, VFS
could drop replies coming from the driver. This patch returns VFS to
a situation where the replies from character drivers are processed
instantly from the main thread, by removing the situations that may
cause VFS to block while handling those replies.

- change the locking model for select, so that it will never block
  on any processing that happens after the select call has been set
  up, in particular processing of character driver select replies;
- clearly mark all select routines that may never block;
- protect against race conditions in do_select as result of the
  locking that still does happen there (as is required for pipes);
- also handle select timers from the main thread;
- move processing of character driver replies into device.c.

Change-Id: I4dc8e69f265cbd178de0fbf321d35f58f067cc57
2014-02-18 11:25:03 +01:00
David van Moolenbroek
2e9f4d0198 VFS: properly cancel select queries on unpause
Change-Id: I16e71db3f5c1bcc7ba6045bc9f02b13d71dc31eb
2014-02-18 11:25:03 +01:00
David van Moolenbroek
87aefd7eb2 VFS: remove support for sync char driver protocol
Change-Id: I57cc870a053b813b3a3fc45da46606ea84fe4cb1
2014-02-18 11:25:03 +01:00
David van Moolenbroek
6331e8f845 Retire the synchronous character driver protocol
- change all sync char drivers into async drivers;
- retire support for the sync protocol in libchardev;
- remove async dev style, as this is now the default;
- remove dev_status from VFS;
- clean up now-unused protocol messages.

Change-Id: I6aacff712292f6b29f2ccd51bc1e7d7003723e87
2014-02-18 11:25:02 +01:00
Lionel Sambuc
cfd3379bb1 Removing CSU patches
* Removed startup code patches in lib/csu regarding kernel to userland
   ABI.

 * Aligned stack layout on NetBSD stack layout.

 * Generate valid stack pointers instead of offsets by taking into account
   _minix_kerninfo->kinfo->user_sp.

 * Refactored stack generation, by moving part of execve in two
   functions {minix_stack_params(), minix_stack_fill()} and using them
   in execve(), rs and vm.

 * Changed load offset of rtld (ld.so) to:
      execi.args.stack_high - execi.args.stack_size - 0xa00000
   which is 10MB below the main executable stack.

Change-Id: I839daf3de43321cded44105634102d419cb36cec
2014-02-18 11:25:02 +01:00
David van Moolenbroek
24ed4e38de Remove support for obsolete 3.2.1 ABI
Change-Id: I76b4960bda41f55d9c42f8c99c5beae3424ca851
2014-02-18 11:25:02 +01:00
David van Moolenbroek
cc810ee4d9 VFS/FS: replace protocol version with flag field
The main motivation for this change is that only Loris supports
multithreading, and Loris supports dynamic thread allocation, so the
number of supported threads can be implemented as a bit flag (i.e.,
either 1 or "at least as many as VFS has"). The ABI break obviates the
need to support file system versioning at this time, and several
other aspects are better implemented as flags as well. Other changes:

- replace peek/bpeek test upon mount with FS flag as well;
- mark libsffs as 64-bit file size capable;
- remove old (3.2.1) getdents support.

Change-Id: I313eace9c50ed816656c31cd47d969033d952a03
2014-02-18 11:25:02 +01:00
David van Moolenbroek
266239fe64 Implement support for getvfsstat(2)
Change-Id: I99b697919d411c57105de561105beefc7d1d309a
2014-02-18 11:25:02 +01:00
David van Moolenbroek
7113bcb896 Redo mount(2)/umount(2) ABI
- pass in file system type through mount(2), and return this type in
  statvfs structures as generated by [f]statvfs(2);
- align mount flags field with NetBSD's, splitting out service flags
  which are not to be passed to VFS;
- remove limitation of mount ABI to 16-byte labels, so that labels
  can be made larger in the future;
- introduce new m11 message union type for mount(2) as side effect.

Change-Id: I88b7710e297e00a5e4582ada5243d3d5c2801fd9
2014-02-18 11:25:01 +01:00
David van Moolenbroek
61ed526374 Align "struct statvfs" with NetBSD
This is a requirement for implementing calls such as getmntinfo(3).
VFS is now responsible for filling in some of the structure's fields.

Change-Id: I0c1fa78019587efefd2949b3be38cd9a7ddc2ced
2014-02-18 11:25:01 +01:00
David van Moolenbroek
f10229eafb VFS/FS: remove fstatfs(2) and REQ_FSTATFS
The fstatfs(3) call now uses fstatvfs(2).

Change-Id: I3fa5d31f078457b4d80418c23060bb2c148cb460
2014-02-18 11:25:01 +01:00
Thomas Veerman
32e916ad53 VFS: use 64-bit file offsets in all requests
Change-Id: I735c4068135474aff2c397f4bc9fb147a618b453
2014-02-18 11:25:01 +01:00
Thomas Veerman
c1a31d53d9 stat.h: remove some big_ types
Change-Id: I84017db3d54edfb823cc52e02d0b07fccb003988
2014-02-18 11:25:01 +01:00
Thomas Veerman
c66fd312d4 VFS-FS protocol: add versioning
Change-Id: Ice6fbfd4b535b7435653fa08b27a3378d1cfdbf8
2014-02-18 11:25:00 +01:00
Xiaoguang Sun
64f10ee644 Implement getrusage
Implement getrusage.
These fields of struct rusage are not supported and always set to zero at this time
long ru_nswap;           /* swaps */
long ru_inblock;         /* block input operations */
long ru_oublock;         /* block output operations */
long ru_msgsnd;          /* messages sent */
long ru_msgrcv;          /* messages received */
long ru_nvcsw;           /* voluntary context switches */
long ru_nivcsw;          /* involuntary context switches */

test75.c is the unit test for this new function

Change-Id: I3f1eb69de1fce90d087d76773b09021fc6106539
2013-07-01 23:00:47 +02:00
Ben Gras
33a7ac7557 vfs: mmap support
. libc: add vfs_mmap, a way for vfs to initiate mmap()s.
	  This is a good special case to have as vfs is a slightly
	  different client from regular user processes. It doesn't do it
	  for itself, and has the dev & inode info already so the callback
	  to VFS for the lookup isn't necessary. So it has different info
	  to have to give to VM.
	. libc: also add minix_mmap64() that accepts a 64-bit offset, even
	  though our off_t is still 32 bit now.
	. On exec() time, try to mmap() in the executable if available.
	  (It is not yet available in this commit.)
	. To support mmap(), add do_vm_call that allows VM to lookup
	  (to ino+dev), do i/o from and close FD's on behalf of other
	  processes.

Change-Id: I831551e45a6781c74313c450eb9c967a68505932
2013-05-31 15:42:00 +00:00
Ben Gras
44f34e53d5 VFS: Implement REQ_BPEEK.
This commit introduces a new request type called REQ_BPEEK. It
requests minor device blocks from the FS.  Analogously to REQ_PEEK,
it requests the filesystem to get the requested blocks into its
cache, without actually copying the result anywhere.

Change-Id: If1d06645b0e17553a64b3167091e9d12efeb3d6f
2013-04-24 10:18:16 +00:00
Xiaoguang Sun
20e6c9329f Change function prototype to use endpoint_t instead of int 2013-04-23 17:15:15 +02:00
Ben Gras
cef94e096e vfs: make m_out non-global
m_out is shared between threads as the reply message, and it can happen
results get overwritten by another thread before the reply is sent. This
change

	. makes m_out local to the message handling function,
	  declared on the stack of the caller
	. forces callers of reply() to give it a message, or
	  declare the reply message has no significant fields except
	  for the return code by calling replycode()

Change-Id: Id06300083a63c72c00f34f86a5c7d96e4bbdf9f6
2013-04-12 23:40:38 +00:00
Antoine Leca
9131e98a7d utimens(2) system call
Variant of utime(2) with struct timespec (with ns precision)
instead of time_t values; also allows for tv_nsec members
the values UTIME_NOW (force update to current time) or
UTIME_OMIT (allow to set either atim or mtim independently.)

Provides a superset of utimes(2), futimes(2), lutimes(2),
and futimens(2).
Provides the same subset of utimensat(2) as does NetBSD 6.
Also import utimens() and lutimeNS() from NetBSD-current.
2013-04-12 18:55:39 +00:00
Antoine Leca
4069cef7f9 Subsecond timestamps support for FS
Expand REQ_UTIME to include tv_nsec members
(as in struct timespec) in addition to tv_sec==time_t

Designed with help from David van Moolenbroek
2013-04-12 11:11:59 +02:00
Ben Gras
a9f55a2e46 VFS, FSes: add REQ_PEEK request type
REQ_PEEK behaves just like REQ_READ except that it does not copy
data anywhere, just obtains the blocks from the FS into the cache.

To be used by the future mmap implementation.

Change-Id: I1b56de304f0a7152b69a72c8962d04258adb44f9
2013-03-07 10:57:38 +00:00
Thomas Veerman
49ad4e8888 Spring cleanup
Remove old versions of system calls and system calls that don't have
a libc api interface anymore (dup, dup2, creat).

VFS still contains support for old system call numbers for the new stat
system calls (i.e., 65, 66, 67) to keep supporting old binaries built for
MINIX 3.2.1 (prior to the release).

Change-Id: I721779b58a50c7eeae20669de24658d55d69b25b
2013-03-06 09:56:08 +00:00
Thomas Veerman
473547c777 VFS: implement pipe2
Change-Id: Iedc8042dd73a903456b25ba665d12577f5589ca2
2013-02-28 10:08:53 +00:00
Thomas Veerman
fa78dc389f socket: implement SOCK_CLOEXEC and SOCK_NONBLOCK
Change-Id: I3fa36fa999c82a192d402cb4d913bd397e106e53
2013-02-28 10:08:53 +00:00
Thomas Veerman
3de8d1cf6e VFS/PFS: remove notion of position in pipes
Because pipes have no file position. VFS maintained (file) offsets into a
buffer internal to PFS and stored them in vnodes for simplicity, mixing
the responsibilities of filp and vnode objects.

With this patch PFS ignores the position field in REQ_READ and REQ_WRITE
requests making VFS' job a lot simpler.
2013-01-11 09:18:35 +00:00
Thomas Veerman
7c8b3ddfed VFS: fix locking bugs
.sync and fsync used unnecessarily restrictive locking type
.fsync violated locking order by obtaining a vmnt lock after a filp lock
.fsync contained a TOCTOU bug
.new_node violated locking rules (didn't upgrade lock upon file creation)
.do_pipe used unnecessarily restrictive locking type
.always lock pipes exclusively; even a read operation might require to do
 a write on a vnode object (update pipe size)
.when opening a file with O_TRUNC, upgrade vnode lock when truncating
.utime used unnecessarily restrictive locking type
.path parsing:
  .always acquire VMNT_WRITE or VMNT_EXCL on vmnt and downgrade to
   VMNT_READ if that was what was actually requested. This prevents the
   following deadlock scenario:
   thread A:
     lock_vmnt(vmp, TLL_READSER);
     lock_vnode(vp, TLL_READSER);
     upgrade_vmnt_lock(vmp, TLL_WRITE);

   thread B:
     lock_vmnt(vmp, TLL_READ);
     lock_vnode(vp, TLL_READSER);

   thread A will be stuck in upgrade_vmnt_lock and thread B is stuck in
   lock_vnode. This happens when, for example, thread A tries create a
   new node (open.c:new_node) and thread B tries to do eat_path to
   change dir (stadir.c:do_chdir). When the path is being resolved, a
   vnode is always locked with VNODE_OPCL (TLL_READSER) and then
   downgraded to VNODE_READ if read-only is actually requested. Thread
   A locks the vmnt with VMNT_WRITE (TLL_READSER) which still allows
   VMNT_READ locks. Thread B can't acquire a lock on the vnode because
   thread A has it; Thread A can't upgrade its vmnt lock to VMNT_WRITE
   (TLL_WRITE) because thread B has a VMNT_READ lock on it.

   By serializing vmnt locks during path parsing, thread B can only
   acquire a lock on vmp when thread A has completely finished its
   operation.
2013-01-11 09:18:35 +00:00
Thomas Veerman
179261a9b6 mtab: support moving mount points
Also fix canonical_path function; it fails to parse some paths
2012-11-29 10:50:51 +00:00
Thomas Veerman
d9f4f71916 Implement dynamic mtab support
With this patch /etc/mtab becomes obsolete.
2012-11-26 15:20:18 +00:00
Thomas Veerman
ed23a7a7d2 VFS: fix reboot panic with mounted FUSE FS
Upon reboot VFS semi-exits all processes and unmounts the file system.
However, upon unmount, exiting FUSE file systems might need service from
the file system (due to libc). As the FUSE process is halfway the exit
procedure, it doesn't have a valid root directory and working directory.
Trying to do system calls then triggers a sanity check in VFS.

This fix first exits normal processes which should then allow for
unmounting FUSE file systems. Then VFS exits all processes including
File Servers and unmounts the rest of the file system.
2012-11-14 13:18:16 +00:00
Arne Welzel
e35c4f78d2 VFS: fix check_bsf() locking
The check_bsf() macro uses assert(mutex_trylock(&bsf_lock)) and
assumes bsf_lock is locked afterwards. This breaks when compiling
with NOASSERTS="yes". Also: macro to function transition.
2012-09-28 14:57:34 +02:00
Thomas Veerman
992799b91f VFS: make all IPC asynchronous
By decoupling synchronous drivers from VFS, we are a big step closer to
supporting driver crashes under all circumstances. That is, VFS can't
become stuck on IPC with a synchronous driver (e.g., INET) and can
recover from crashing block drivers during open/close/ioctl or during
communication with an FS.

In order to maintain serialized communication with a synchronous driver,
the communication is wrapped by a mutex on a per driver basis (not major
numbers as there can be multiple majors with identical endpoints). Majors
that share a driver endpoint point to a single mutex object.

In order to support crashes from block drivers, the file reopen tactic
had to be changed; first reopen files associated with the crashed
driver, then send the new driver endpoint to FSes. This solves a
deadlock between the FS and the block driver;
  - VFS would send REQ_NEW_DRIVER to an FS, but he FS only receives it
    after retrying the current request to the newly started driver.
  - The block driver would refuse the retried request until all files
    had been reopened.
  - VFS would reopen files only after getting a reply from the initial
    REQ_NEW_DRIVER.

When a character special driver crashes, all associated files have to
be marked invalid and closed (or reopened if flagged as such). However,
they can only be closed if a thread holds exclusive access to it. To
obtain exclusive access, the worker thread (which handles the new driver
endpoint event from DS) schedules a new job to garbage collect invalid
files. This way, we can signal the worker thread that was talking to the
crashed driver and will release exclusive access to a file associated
with the crashed driver and prevent the garbage collecting worker thread
from dead locking on that file.

Also, when a character special driver crashes, RS will unmap the driver
and remap it upon restart. During unmapping, associated files are marked
invalid instead of waiting for an endpoint up event from DS, as that
event might come later than new read/write/select requests and thus
cause confusion in the freshly started driver.

When locking a filp, the usage counters are no longer checked. The usage
counter can legally go down to zero during filp invalidation while there
are locks pending.

DS events are handled by a separate worker thread instead of the main
thread as reopening files could lead to another crash and a stuck thread.
An additional worker thread is then necessary to unlock it.

Finally, with everything asynchronous a race condition in do_select
surfaced. A select entry was only marked in use after succesfully sending
initial select requests to drivers and having to wait. When multiple
select() calls were handled there was opportunity that these entries
were overwritten. This had as effect that some select results were
ignored (and select() remained blocking instead if returning) or do_select
tried to access filps that were not present (because thrown away by
secondary select()). This bug manifested itself with sendrecs, but was
very hard to reproduce. However, it became awfully easy to trigger with
asynsends only.
2012-09-17 11:01:45 +00:00
Thomas Veerman
77dbd766c1 VFS: Use safe string copy functions 2012-07-16 10:57:43 +00:00
Thomas Veerman
7b81254069 VFS: simplify stat for pipes
According to POSIX the st_size field of struct stat is undefined for
fifos and anonymous pipes. Thus we can do anything we want. We save a
copy by not being accurate on pipe sizes.
2012-04-27 08:50:49 +00:00
Ben Gras
53002f6f6c recognize and execute dynamically linked executables
. generalize libexec slightly to get some more necessary information
	  from ELF files, e.g. the interpreter
	. execute dynamically linked executables when exec()ed by VFS
	. switch to netbsd variant of elf32.h exclusively, solves some
	  conflicting headers
2012-04-16 00:41:42 +00:00
Thomas Veerman
91a38b6d4e VFS: fix dead lock
When running out of worker threads to handle device replies a dead
lock resolver thread is used. However, it was only used for FS
endpoints; it is now used for "system processes" (drivers and FS
endpoints). Also, drivers were marked as system process when they
were not "forced" to map (i.e., mapping was done before endpoint was
alive).
2012-04-13 13:19:10 +00:00