Commit graph

257 commits

Author SHA1 Message Date
Thomas Veerman
66dbf73049 VFS: fix locking bug in clone_opcl
When VFS runs out of vnodes after closing a vnode in opcl, common_open
will try to unlock a vnode through unlock_filp that has already been
unlocked in clone_opcl. By first obtaining and locking a new vnode this
situation is prevented; if there are no free vnodes, common_open will
unlock a still locked vnode.
2012-07-30 10:01:16 +00:00
Thomas Veerman
f6b0d662b5 VFS: check path components for NAME_MAX length 2012-07-30 09:44:58 +00:00
David van Moolenbroek
0b4c154160 VFS: call req_inhibread again 2012-07-19 14:36:51 +00:00
David van Moolenbroek
e0742978f1 VFS: do not resolve symlinks in rename(2) 2012-07-18 14:59:45 +00:00
Thomas Veerman
0d3ccd8908 VFS: fix coverity defects 2012-07-17 10:29:22 +00:00
Thomas Veerman
fd60f03129 VFS: remove support for sync FS communication 2012-07-17 10:12:53 +00:00
Thomas Veerman
06f49fe167 VFS: prevent buffer overflow
If an FS returns faulty struct dirent data, VFS could overflow
a buffer that holds this data.
2012-07-17 08:49:41 +00:00
Ben Gras
cbcdb838f1 various coverity-inspired fixes
. some strncpy/strcpy to strlcpy conversions
	. new <minix/param.h> to avoid including other minix headers
	  that have colliding definitions with library and commands code,
	  causing parse warnings
	. removed some dead code / assignments
2012-07-16 14:00:56 +02:00
Thomas Veerman
77dbd766c1 VFS: Use safe string copy functions 2012-07-16 10:57:43 +00:00
Ben Gras
50e2064049 No more intel/minix segments.
This commit removes all traces of Minix segments (the text/data/stack
memory map abstraction in the kernel) and significance of Intel segments
(hardware segments like CS, DS that add offsets to all addressing before
page table translation). This ultimately simplifies the memory layout
and addressing and makes the same layout possible on non-Intel
architectures.

There are only two types of addresses in the world now: virtual
and physical; even the kernel and processes have the same virtual
address space. Kernel and user processes can be distinguished at a
glance as processes won't use 0xF0000000 and above.

No static pre-allocated memory sizes exist any more.

Changes to booting:
        . The pre_init.c leaves the kernel and modules exactly as
          they were left by the bootloader in physical memory
        . The kernel starts running using physical addressing,
          loaded at a fixed location given in its linker script by the
          bootloader.  All code and data in this phase are linked to
          this fixed low location.
        . It makes a bootstrap pagetable to map itself to a
          fixed high location (also in linker script) and jumps to
          the high address. All code and data then use this high addressing.
        . All code/data symbols linked at the low addresses is prefixed by
          an objcopy step with __k_unpaged_*, so that that code cannot
          reference highly-linked symbols (which aren't valid yet) or vice
          versa (symbols that aren't valid any more).
        . The two addressing modes are separated in the linker script by
          collecting the unpaged_*.o objects and linking them with low
          addresses, and linking the rest high. Some objects are linked
          twice, once low and once high.
        . The bootstrap phase passes a lot of information (e.g. free memory
          list, physical location of the modules, etc.) using the kinfo
          struct.
        . After this bootstrap the low-linked part is freed.
        . The kernel maps in VM into the bootstrap page table so that VM can
          begin executing. Its first job is to make page tables for all other
          boot processes. So VM runs before RS, and RS gets a fully dynamic,
          VM-managed address space. VM gets its privilege info from RS as usual
          but that happens after RS starts running.
        . Both the kernel loading VM and VM organizing boot processes happen
	  using the libexec logic. This removes the last reason for VM to
	  still know much about exec() and vm/exec.c is gone.

Further Implementation:
        . All segments are based at 0 and have a 4 GB limit.
        . The kernel is mapped in at the top of the virtual address
          space so as not to constrain the user processes.
        . Processes do not use segments from the LDT at all; there are
          no segments in the LDT any more, so no LLDT is needed.
        . The Minix segments T/D/S are gone and so none of the
          user-space or in-kernel copy functions use them. The copy
          functions use a process endpoint of NONE to realize it's
          a physical address, virtual otherwise.
        . The umap call only makes sense to translate a virtual address
          to a physical address now.
        . Segments-related calls like newmap and alloc_segments are gone.
        . All segments-related translation in VM is gone (vir2map etc).
        . Initialization in VM is simpler as no moving around is necessary.
        . VM and all other boot processes can be linked wherever they wish
          and will be mapped in at the right location by the kernel and VM
          respectively.

Other changes:
        . The multiboot code is less special: it does not use mb_print
          for its diagnostics any more but uses printf() as normal, saving
          the output into the diagnostics buffer, only printing to the
          screen using the direct print functions if a panic() occurs.
        . The multiboot code uses the flexible 'free memory map list'
          style to receive the list of free memory if available.
        . The kernel determines the memory layout of the processes to
          a degree: it tells VM where the kernel starts and ends and
          where the kernel wants the top of the process to be. VM then
          uses this entire range, i.e. the stack is right at the top,
          and mmap()ped bits of memory are placed below that downwards,
          and the break grows upwards.

Other Consequences:
        . Every process gets its own page table as address spaces
          can't be separated any more by segments.
        . As all segments are 0-based, there is no distinction between
          virtual and linear addresses, nor between userspace and
          kernel addresses.
        . Less work is done when context switching, leading to a net
          performance increase. (8% faster on my machine for 'make servers'.)
	. The layout and configuration of the GDT makes sysenter and syscall
	  possible.
2012-07-15 22:30:15 +02:00
Ben Gras
0fb2f83da9 drop from segments physcopy/vircopy invocations
. sys_vircopy always uses D for both src and dst
	. sys_physcopy uses PHYS_SEG if and only if corresponding
	  endpoint is NONE, so we can derive the mode (PHYS_SEG or D)
	  from the endpoint arg in the kernel, dropping the seg args
	. fields in msg still filled in for backwards compatability,
	  using same NONE-logic in the library
2012-06-18 12:28:40 +00:00
Ben Gras
2bfeeed885 drop segment from safecopy invocations
. all invocations were S or D, so can safely be dropped
	  to prepare for the segmentless world
	. still assign D to the SCP_SEG field in the message
	  to make previous kernels usable
2012-06-16 16:22:51 +00:00
Ben Gras
85ff5a947e dumpcore: use ptrace function to trigger a coredump
. dumpcore currently relies on minix segments
	. also ptrace dumpcore fix
2012-06-15 12:13:50 +02:00
Ben Gras
769af57274 further libexec generalization
. new mode for sys_memset: include process so memset can be
	  done in physical or virtual address space.
	. add a mode to mmap() that lets a process allocate uninitialized
	  memory.
	. this allows an exec()er (RS, VFS, etc.) to request uninitialized
	  memory from VM and selectively clear the ranges that don't come
	  from a file, leaving no uninitialized memory left for the process
	  to see.
	. use callbacks for clearing the process, clearing memory in the
	  process, and copying into the process; so that the libexec code
	  can be used from rs, vfs, and in the future, kernel (to load vm)
	  and vm (to load boot-time processes)
2012-06-07 15:15:02 +02:00
Ben Gras
040362e379 exec() cleanup, generalization, improvement
. make exec() callers (i.e. vfs and rs) determine the
	  memory layout by explicitly reserving regions using
	  mmap() calls on behalf of the exec()ing process,
	  i.e. handling all of the exec logic, thereby eliminating
	  all special exec() knowledge from VM.
	. the new procedure is: clear the exec()ing process
	  first, then call third-party mmap()s to reserve memory, then
	  copy the executable file section contents in, all using callbacks
	  tailored to the caller's way of starting an executable
	. i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM
	  as with rigid 2-section arguments
	. this naturally allows generalizing exec() by simply loading
	  all ELF sections
	. drop/merge of lots of duplicate exec() code into libexec
	. not copying the code sections to vfs and into the executable
	  again is a measurable performance improvement (about 3.3% faster
	  for 'make' in src/servers/)
2012-06-07 15:15:01 +02:00
Ben Gras
41b869d4d6 drop aout support
justification: soon we won't be able to execute sep I&D aouts at
all (because of the vanishing segments), which was the default mode
to generate them so most binaries will be sep I&D.

this makes the vfs/rs exec() unification work simpler.

after unification, common I&D aout could be added back quite simply.
2012-06-07 12:43:16 +02:00
David van Moolenbroek
1817f7fc07 VFS: fix "process already free" panic on reboot
Reported by Claudiu Dan Gheorghe, debugged by Thomas and myself
2012-05-02 17:42:50 +02:00
Thomas Veerman
068d443d12 VFS: unlock vmnt when out of vnodes 2012-04-27 08:51:13 +00:00
Thomas Veerman
b6ff38065f VFS: release what can be released
Only attempt to release blocked processes that are blocked. There is
no use in trying to find more blocked processes than we know that are
blocked (on a pipe).
2012-04-27 08:51:02 +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
Thomas Veerman
db8198d99d VFS: use S_IS* macros 2012-04-27 08:49:38 +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
Ben Gras
755102d67f AT_SUN_EXECNAME support
. vfs: pass execname in aux vectors
	. ld.elf_so: use this to expand $ORIGIN
	. this requires the executable to reserve more
	  space at exec() calling time
2012-04-26 13:32:39 +02:00
David van Moolenbroek
26f817243b VFS: reimplement truncate mtime/ctime fix
POSIX mandates that a file's modification and change time be left
untouched upon truncate/ftruncate iff the file size does not change.
However, an open(O_TRUNC) call must always update the modification and
change time of the file, even if it was already zero-sized. VFS uses
the file systems' truncate call to implement O_TRUNC. This patch
replaces git-255ae85, which did not take into account the open case.
The size check is now moved into VFS, so that individual file systems
need not check for this case anymore.
2012-04-20 11:35:59 +02:00
Ben Gras
3945cfbfd3 block ioctls: pass request number 2012-04-18 11:01:15 +02:00
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
26ec619a30 VFS: fix filp reuse race
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.
2012-04-13 13:22:57 +00:00
Thomas Veerman
e292ba487e VFS: more three-level-lock sanity checking 2012-04-13 13:22:42 +00:00
Thomas Veerman
933120b0b1 VFS: add getting active threads control msg 2012-04-13 13:21:01 +00:00
Thomas Veerman
e1a73469c8 VFS: remove debug print 2012-04-13 13:20:28 +00:00
Thomas Veerman
c2bb739760 VFS: let know when skipping reply 2012-04-13 13:19:45 +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
Thomas Veerman
b956493367 VFS: fix new signed/unsigned comparisons 2012-04-13 13:00:11 +00:00
Thomas Veerman
defe329519 VFS: warnings are errors 2012-04-13 12:59:32 +00:00
Thomas Veerman
0d63d9e125 VFS: enable sending control messages 2012-04-13 12:54:55 +00:00
Thomas Veerman
f571466c56 VFS: find job only if request is an transaction 2012-04-13 12:52:52 +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
1e2b3f4326 vfs: more regions for coredumps 2012-04-12 14:29:59 +02:00
Ben Gras
204ae72525 retire _ANSI and <minix/ansi.h> 2012-03-25 21:58:27 +02:00
Ben Gras
7336a67dfe retire PUBLIC, PRIVATE and FORWARD 2012-03-25 21:58:14 +02:00
Ben Gras
6a73e85ad1 retire _PROTOTYPE
. only good for obsolete K&R support
	. also remove a stray ansi.h and the proto cmd
2012-03-25 16:17:10 +02:00
David van Moolenbroek
e8d2d2f6b6 libminc-related updates
- add files needed for acpi, ahci, fbd, vfs to libminc
- remove "-lc" from their respective makefiles
- remove setenv from libminc (requires initialization)
2012-03-12 23:16:45 +01:00
Tomas Hruby
72b7abd1a1 VFS - no CANCEL for async non-blocking operations
- 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
2012-03-02 15:44:48 +00:00
Tomas Hruby
f19d8df184 VFS : simplification of handling asyn selects
- 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)
2012-03-02 15:44:48 +00:00
Tomas Hruby
369a12704f VFS - dev_style_asyn()
- dev_style_asyn() tests whether a device is asynchronous

 - simplifies code and helps readability
2012-03-02 15:44:47 +00:00
Tomas Hruby
35eb88461d VFS - cancel_nblock()
- duplicate code in dev_io() which sends CANCEL in case of a
  non-blocking operation moved to cancel_nblock()
2012-03-02 15:44:47 +00:00
Thomas Veerman
1efb51b1de VFS: improve crashed FS resource cleanup
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.
2012-02-22 13:54:35 +00:00
Thomas Veerman
5ff845212e VFS: remove unused variables 2012-02-21 10:21:05 +00:00
Thomas Veerman
0c1cd8720a VFS: fix last_dir not returning last directory
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.
2012-02-21 10:21:05 +00:00
Thomas Veerman
230ea1ce13 VFS: remove erroneous assert
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.
2012-02-20 09:17:42 +00:00