Commit graph

48 commits

Author SHA1 Message Date
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
de975579a4 Rename SYSCTL kernel call to DIAGCTL
Change-Id: I1b17373f01808d887dcbeab493838946fbef4ef6
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
1e7b45c682 VFS: fix interruption of blocking pipe operations
POSIX states that when interrupted, partially successful pipe
operations should return the partial result rather than EINTR. VFS
previously wouldn't look at the partial result, and not clear it
either, which would result in a panic upon the next pipe operation.

Change-Id: Ia1eb72b4b77394051444e63a1390d49bb315eb04
2014-02-18 11:25:03 +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
c7fbafe1ad VFS: remove FP_BLOCKED_ON_DOPEN
These days, DEV_OPEN calls to character drivers block the calling
thread until completion or failure, and thus never return SUSPEND to
the caller. The same already applied to BDEV_OPEN calls to block
drivers. It has thus become impossible for a process to enter a state
of being blocked on a device open call.

There is currently no support for restarting device open calls to
restarted character drivers. This support was present in the _DOPEN
logic, but was already no longer triggering. In the future, this case
should be handled by the thread performing the open request.

Change-Id: I6cc1e7b4c9ed116c6ce160b315e6e060124dce00
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
Ben Gras
8f2749cca8 vfs: patch for unpause()/revive() race condition
. unpause() and revive() can race - revive() can run during
	  a device i/o unblock, causing two sendnb()s to occur, and the
	  2nd one to fail
	. this can easily happen when a process is blocking on tty and
	  is then killed by a signal - tty cancels the i/o and then
	  kills the process by a signal

Change-Id: Ia319acaedfa336b78c030a2c4af7246959bdcf87
2013-06-14 23:58:43 +02:00
Ben Gras
9178749e13 libc syslog, syslogd, logger, uds fixes
changes necessary for libc syslog() using a unix domain socket.

	. libc syslog: don't use send() connect() for unix
	  datagram sockets, minix wants write() and ioctl()
	. syslogd: listen on _PATH_LOG unix domain socket
	. logger: warnings fixes
	. pfs: make uds dgram socket type nonblocking so
	  syslog() doesn't block
	. vfs: add sanity check for empty fd in unpause()

Change-Id: Ied136c6fe0cc288f5a53478f1eebccc1ab1f39fb
2013-06-12 07:04:52 +00:00
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
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
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
06e2adbeaa VFS: fix select again
Change-Id: Ia5e26cdbfe38e3fb293dd57269a76b15c1fe236b
2013-01-25 17:42:36 +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
068d443d12 VFS: unlock vmnt when out of vnodes 2012-04-27 08:51:13 +00:00
Thomas Veerman
96bbc5da3e VFS: I_PIPE is redundant
Also, use S_IS* macros instead of manual comparison.
2012-04-27 08:49:38 +00:00
Thomas Veerman
8f55767619 VFS: make m_in job local
By making m_in job local (i.e., each job has its own copy of m_in instead
of refering to the global m_in) we don't have to store and restore m_in
on every thread yield. This reduces overhead. Moreover, remove the
assumption that m_in is preserved. Do_XXX functions have to copy the
system call parameters as soon as possible and only pass those copies to
other functions.

Furthermore, this patch cleans up some code and uses better types in a lot
of places.
2012-04-13 12:50:38 +00:00
Ben Gras
7336a67dfe retire PUBLIC, PRIVATE and FORWARD 2012-03-25 21:58:14 +02:00
Thomas Veerman
c540bcb001 VFS: various select fixes
- Fix locking bug when unable to send DEV_SELECT request. Upon failure
  VFS tried to cancel the select operation, but this failed due to trying
  to lock a filp that was already locked to send the request in the first
  place. Do_select_request now handles locking of filps itself instead of
  relying on the caller to do it.  This fixes a crash when killing INET.
- Fix failure to revive a process after a non-blocking select operation
  yielded no ready select operations when replying DEV_SEL_REPL1.
- Improve readability by using OK, SUSPEND, and standard error values as
  results instead of having separate macros in select.
- Don't print not having a driver for a major device; after killing a driver
  select will trigger this printf.
2012-02-17 21:09:07 +00:00
Thomas Veerman
80c4685324 VFS: replace VFS with AVFS 2012-02-13 16:53:21 +00:00
Thomas Veerman
aba392e630 Clean up and fix multiple bugs in select:
- Remove redundant code.
 - Always wait for the initial reply from an asynchronous select request,
   even if the select has been satisfied on another file descriptor or
   was canceled due to a serious error.
 - Restart asynchronous selects if upon reply from the driver turns out
   that there are deferred operations (and do not forget we're still
   interested in the results of the deferred operations).
 - Do not hang a non-blocking select when another blocking select on
   the same filp is still blocking.
 - Split blocking operations in read, write, and exceptions (i.e.,
   blocking on read does not imply the write will block as well).
 - Some loops would iterate over OPEN_MAX file descriptors instead of
   the "highest" file descriptor.
 - Use proper internal error return values.
 - A secondary reply from a synchronous driver is essentially the same
   as from an asynchronous driver (the only difference being how the 
   answer is received). Merge.
 - Return proper error code after a driver failure.
 - Auto-detect whether a driver is synchronous or asynchronous.
 - Remove some code duplication.
 - Clean up code (coding style, add missing comments, put all select
   related code together).
2011-04-13 13:25:34 +00:00
David van Moolenbroek
c51cd5fe91 Server/driver protocols: no longer allow third-party copies.
Before safecopies, the IO_ENDPT and DL_ENDPT message fields were needed
to know which actual process to copy data from/to, as that process may
not always be the caller. Now that we have full safecopy support, these
fields have become useless for that purpose: the owner of the grant is
*always* the caller. Allowing the caller to supply another endpoint is
in fact dangerous, because the callee may then end up using a grant
from a third party. One could call this a variant of the confused
deputy problem.

From now on, safecopy calls should always use the caller's endpoint as
grant owner. This fully obsoletes the DL_ENDPT field in the
inet/ethernet protocol. IO_ENDPT has other uses besides identifying the
grant owner though. This patch renames IO_ENDPT to USER_ENDPT, not only
because that is a more fitting name (it should never be used for I/O
after all), but also in order to intentionally break any old system
source code outside the base system. If this patch breaks your code,
fixing it is fairly simple:

- DL_ENDPT should be replaced with m_source;
- IO_ENDPT should be replaced with m_source when used for safecopies;
- IO_ENDPT should be replaced with USER_ENDPT for any other use, e.g.
  when setting REP_ENDPT, matching requests in CANCEL calls, getting
  DEV_SELECT flags, and retrieving of the real user process's endpoint
  in DEV_OPEN.

The changes in this patch are binary backward compatible.
2011-04-11 17:35:05 +00:00
Ben Gras
3badab8b70 vfs - split fp_fd field into fd + callnr fields 2010-07-22 14:55:28 +00:00
Tomas Hruby
6e25ad8b0a Use of all NIL_* defines converted to NULL 2010-05-10 13:26:00 +00:00
Thomas Veerman
0aceb25535 Small cleanup of dead and/or redundant code. 2010-05-06 09:32:40 +00:00
Kees van Reeuwijk
fc7dced1fa Fix printfs with too few or too many parms, remove unused vars, fix incorrect flag tests, other code cleanup. 2010-04-01 13:25:05 +00:00
Ben Gras
35a108b911 panic() cleanup.
this change
   - makes panic() variadic, doing full printf() formatting -
     no more NO_NUM, and no more separate printf() statements
     needed to print extra info (or something in hex) before panicing
   - unifies panic() - same panic() name and usage for everyone -
     vm, kernel and rest have different names/syntax currently
     in order to implement their own luxuries, but no longer
   - throws out the 1st argument, to make source less noisy.
     the panic() in syslib retrieves the server name from the kernel
     so it should be clear enough who is panicing; e.g.
         panic("sigaction failed: %d", errno);
     looks like:
         at_wini(73130): panic: sigaction failed: 0
         syslib:panic.c: stacktrace: 0x74dc 0x2025 0x100a
   - throws out report() - printf() is more convenient and powerful
   - harmonizes/fixes the use of panic() - there were a few places
     that used printf-style formatting (didn't work) and newlines
     (messes up the formatting) in panic()
   - throws out a few per-server panic() functions
   - cleans up a tie-in of tty with panic()

merging printf() and panic() statements to be done incrementally.
2010-03-05 15:05:11 +00:00
Kees van Reeuwijk
1597e701a0 Remove useless variables and the computations on them. 2010-02-19 10:00:32 +00:00
Thomas Veerman
958b25be50 - Introduce support for sticky bit.
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00
Tomas Hruby
8590ac260d Removed dependency of vfs on NR_TASKS macro
- all macros in consts.h that depend on NR_TASKS replaced by a FP_BLOCKED_ON_*

- fp_suspended removed and replaced by fp_blocked_on. Testing whether a process
  is supended is qeual to testing whether fp_blocked_on is FP_BLOCKED_ON_NONE or
  not

- fp_task is valid only if fp_blocked_on == FP_BLOCKED_ON_OTHER

- no need of special values that do not colide with valid and special endpoints
  since they are not used as endpoints anymore

- suspend only takes FP_BLOCKED_ON_* values not endpoints anymore

- suspend(task) replaced by wait_for(task) which sets fp_task so we remember who
  are we waiting for and suspend sets fp_blocked_on to FP_BLOCKED_ON_OTHER to
  signal that we are waiting for some other process

- some functions should take endpoint_t instead of int, fixed
2009-09-22 21:48:26 +00:00
Thomas Veerman
ce916bcb91 Fixed a minor select bug:
- When one does a select on a file descriptor that is meaningless for that particular file type, select shall indicate that the file descriptor is ready for that particular operation and that the file descriptor has no exceptional condition pending.
2009-07-14 09:39:05 +00:00
Ben Gras
dc1238b7b9 make unpause() decrease susp_count, as it shouldn't be decreased
if the process was REVIVING. (susp_count doesn't count those
 processes.) this together with dev_io SELECT suspend side effect
 for asynch. character devices solves the hanging pipe bug. or
 at last vastly improves it.

 added sanity checks, turned off by default.

 made the {NOT_,}{SUSPENDING,REVIVING} constants weirder to
 help sanity checking.
2009-05-08 13:56:41 +00:00
Ben Gras
73ee8b8b99 don't make susp_count negative. 2009-04-02 11:44:26 +00:00
Ben Gras
c078ec0331 Basic VM and other minor improvements.
Not complete, probably not fully debugged or optimized.
2008-11-19 12:26:10 +00:00
Philip Homburg
7387449b23 Support for suspending on character device open and on drivers that need to
be restarted.
2008-02-22 14:47:40 +00:00
Philip Homburg
a116b3aa55 To return the right error, check first is an object is a directory (for
mkdir, rmdir/unlink, mknod), simply pipe code by using v_pipe_rd_pos and
v_pipe_wr_pos directly. Some cleanup work in open.c
2007-08-08 14:01:36 +00:00
Philip Homburg
f46319037b New VFS interface 2007-08-07 12:52:47 +00:00
Philip Homburg
9092146be7 VFS cleanup (mostly open). 2007-01-05 16:36:55 +00:00
Philip Homburg
bafc45a309 First cut at 64-bit file offsets in block devices for mkfs/fsck. 2006-11-27 14:21:43 +00:00
Ben Gras
fa0ba56bc9 Merge of VFS by Balasz Gerofi with Minix trunk. 2006-10-25 13:40:36 +00:00
Renamed from servers/fs/pipe.c (Browse further)