Pipes consist of two filps (read filp and write filp) and a shared
vnode. When the writer leaves the filp reference count drops to
zero and subsequent find_filp()s should not find the filp when a
reader looks for it and the reader gets EOF. However, the pipe()
system call tries to find two filps, marks them in use, and only
after a successful node creation on PFS, overwrites the shared
vnode with the new vnode. Consequently, this leaves a small window
where a just closed 'pipe write filp' gets reused and marked as
present, before becoming the actual new 'pipe write filp' for a new
pipe. A reader for the old pipe will think a writer is present and
wait for that writer to write something or to leave; both actions
should revive the suspended reader. This will never happen and the
reader will be stuck forever.
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).
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.
use the user-supplied point to lookup which region to perform brk() on,
and if it's a reasonable one, do it, no matter what vm's notion of the
heap region is.
This Shared Folders File System library (libsffs) now contains all the
file system logic originally in HGFS. The actual HGFS server code is
now a stub that passes on all the work to libsffs. The libhgfs library
is changed accordingly.
Previously, the mmap address (if given) was merely used as a lower
bound, and then possibly overriden with a hint. Now, the mapping is
first tried at the exact given address. If that fails, the start of
the mmap range is used as lower bound (which is then still overridden
by the hint for efficiency).
This allows two pages to be mapped in at predefined addresses, where
the second address is lower than the first. That was not possible.
remove some old minix-userland-specific stuff
. /etc/ttytab as a file, and minix-compat function (fftyslot()),
replaced by /etc/ttys and new libc functions
. also remove minix-specific nlist(), cuserid(), fttyslot(), v8 regex
functions and <compat/regex.h>
. and remaining minix-only utilities that use them
. also unused <compat/pwd.h> and <compat/syslog.h> and
redundant <sys/sigcontext.h>
- add files needed for acpi, ahci, fbd, vfs to libminc
- remove "-lc" from their respective makefiles
- remove setenv from libminc (requires initialization)
On MFS file systems, the stat(2) call now counts indirect blocks as
part of the st_blocks calculation, in addition to proper initial
rounding of the file size. The returned value is now a true upper
bound on the actual number of 512-byte blocks allocated to the file.
As before, it is not accurate for sparse files.
- libnetsock - internal implementation of a socket on the lwip
server side. it encapsulates the asynchronous protocol
- lwip server - uses libnetsock to work with the asynchronous
protocol
- if an operation (R, W, IOCTL) is non blocking, a flag is set
and sent to the device.
- nothing changes for sync devices
- asyn devices should reply asap if an operation is non-blocking.
We must trust the devices, but we had to trust them anyway to
reply to CANCEL correctly
- we safe sending CANCEL commands to asyn devices. This greatly
simplifies the protocol. Asynchronous devices can always reply
when a reply is ready and do not need to deal with other
situations
- currently, none of our drivers use the flags since they drive
virtual devices which do not block
- select_request_async() returns no ops by default
- wantops in do_select() always set correctly, do_select() does
not need a special case for SUSPEND (and ugly code)
When VFS detects that an FS has crashed and tries to clean up
resources, it marks fairly late in the process that a vmnt is not
to be used again (to send requests to). This allows a thread to
become blocked on a vmnt after all blocked threads were stopped, but
before it finds out it shouldn't try to send to that vmnt.
If the provided path was only a single component (i.e., without
slashes), then last_dir would return early and skip the symlink
detection (i.e., check whether the path ends in a symlink and resolve
that first before returning). This bug triggered an assert in open
which expects that an advance after an last_dir (with VMNT_WRITE lock)
does not yield another vmnt lock.
The assert was meant as an additional check to the assert in link.c:198.
The reasoning behind the assert in link.c:198 is that once you've
obtained a write lock on a vmnt, you can't get an additional read lock
on the same vmnt. However, that does not always hold for the assert in
path.c:281 where the situation could be that you've obtained a read lock
and managed to get another read lock (this is possible). In other words,
the assert in path.c:281 is not the right place to check for that
situation.
- 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.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.
Changes in this commit:
. drop boot monitor -> allowing dropping ack support
. facility to copy ELF boot files to /boot so that old boot monitor
can still boot fairly easily, see UPDATING
. no more ack-format libraries -> single-case libraries
. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
. drop several ack toolchain commands, but not all support
commands (e.g. aal is gone but acksize is not yet).
. a few libc files moved to netbsd libc dir
. new /bin/date as minix date used code in libc/
. test compile fix
. harmonize includes
. /usr/lib is no longer special: without ack, /usr/lib plays no
kind of special bootstrapping role any more and bootstrapping
is done exclusively through packages, so releases depend even
less on the state of the machine making them now.
. rename nbsd_lib* to lib*
. reduce mtree
- When cancelling ioctls, VFS did not remember which file descriptor
to cancel and sent bogus to the driver.
- Select state was not cleaned up when select()ing process was
interrupted.
- Process trying to do a system call at the exact same time as a user
trying to interrupt the process, could cause the system call worker
thread to overwrite state belonging to the worker thread trying to
exit the process. This led to hanging threads and eventual system hang
when this happens often enough.
