- allow PM to tell sys_runctl() whether to use delay call feature
- only use this feature in PM for delivering signals - not for exits
- do better error checking in PM on sys_runctl() calls
- rename SIGKREADY to SIGNDELAY
o Support for ptrace T_ATTACH/T_DETACH and T_SYSCALL
o PM signal handling logic should now work properly, even with debuggers
being present
o Asynchronous PM/VFS protocol, full IPC support for senda(), and
AMF_NOREPLY senda() flag
DETAILS
Process stop and delay call handling of PM:
o Added sys_runctl() kernel call with sys_stop() and sys_resume()
aliases, for PM to stop and resume a process
o Added exception for sending/syscall-traced processes to sys_runctl(),
and matching SIGKREADY pseudo-signal to PM
o Fixed PM signal logic to deal with requests from a process after
stopping it (so-called "delay calls"), using the SIGKREADY facility
o Fixed various PM panics due to race conditions with delay calls versus
VFS calls
o Removed special PRIO_STOP priority value
o Added SYS_LOCK RTS kernel flag, to stop an individual process from
running while modifying its process structure
Signal and debugger handling in PM:
o Fixed debugger signals being dropped if a second signal arrives when
the debugger has not retrieved the first one
o Fixed debugger signals being sent to the debugger more than once
o Fixed debugger signals unpausing process in VFS; removed PM_UNPAUSE_TR
protocol message
o Detached debugger signals from general signal logic and from being
blocked on VFS calls, meaning that even VFS can now be traced
o Fixed debugger being unable to receive more than one pending signal in
one process stop
o Fixed signal delivery being delayed needlessly when multiple signals
are pending
o Fixed wait test for tracer, which was returning for children that were
not waited for
o Removed second parallel pending call from PM to VFS for any process
o Fixed process becoming runnable between exec() and debugger trap
o Added support for notifying the debugger before the parent when a
debugged child exits
o Fixed debugger death causing child to remain stopped forever
o Fixed consistently incorrect use of _NSIG
Extensions to ptrace():
o Added T_ATTACH and T_DETACH ptrace request, to attach and detach a
debugger to and from a process
o Added T_SYSCALL ptrace request, to trace system calls
o Added T_SETOPT ptrace request, to set trace options
o Added TO_TRACEFORK trace option, to attach automatically to children
of a traced process
o Added TO_ALTEXEC trace option, to send SIGSTOP instead of SIGTRAP upon
a successful exec() of the tracee
o Extended T_GETUSER ptrace support to allow retrieving a process's priv
structure
o Removed T_STOP ptrace request again, as it does not help implementing
debuggers properly
o Added MINIX3-specific ptrace test (test42)
o Added proper manual page for ptrace(2)
Asynchronous PM/VFS interface:
o Fixed asynchronous messages not being checked when receive() is called
with an endpoint other than ANY
o Added AMF_NOREPLY senda() flag, preventing such messages from
satisfying the receive part of a sendrec()
o Added asynsend3() that takes optional flags; asynsend() is now a
#define passing in 0 as third parameter
o Made PM/VFS protocol asynchronous; reintroduced tell_fs()
o Made PM_BASE request/reply number range unique
o Hacked in a horrible temporary workaround into RS to deal with newly
revealed RS-PM-VFS race condition triangle until VFS is asynchronous
System signal handling:
o Fixed shutdown logic of device drivers; removed old SIGKSTOP signal
o Removed is-superuser check from PM's do_procstat() (aka getsigset())
o Added sigset macros to allow system processes to deal with the full
signal set, rather than just the POSIX subset
Miscellaneous PM fixes:
o Split do_getset into do_get and do_set, merging common code and making
structure clearer
o Fixed setpriority() being able to put to sleep processes using an
invalid parameter, or revive zombie processes
o Made find_proc() global; removed obsolete proc_from_pid()
o Cleanup here and there
Also included:
o Fixed false-positive boot order kernel warning
o Removed last traces of old NOTIFY_FROM code
THINGS OF POSSIBLE INTEREST
o It should now be possible to run PM at any priority, even lower than
user processes
o No assumptions are made about communication speed between PM and VFS,
although communication must be FIFO
o A debugger will now receive incoming debuggee signals at kill time
only; the process may not yet be fully stopped
o A first step has been made towards making the SYSTEM task preemptible
- 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
shared with the kernel, mapped into kernel address space;
kernel is notified of its location. kernel segment size is
increased to make it fit.
- map in kernel and other processes that don't have their
own page table using single 4MB (global) mapping.
- new sanity check facility: objects that are allocated with
the slab allocator are, when running with sanity checking on,
marked readonly until they are explicitly unlocked using the USE()
macro.
- another sanity check facility: collect all uses of memory and
see if they don't overlap with (a) eachother and (b) free memory
- own munmap() and munmap_text() functions.
- exec() recovers from out-of-memory conditions properly now; this
solves some weird exec() behaviour
- chew off memory from the same side of the chunk as where we
start scanning, solving some memory fragmentation issues
- use avl trees for freelist and phys_ranges in regions
- implement most useful part of munmap()
- remap() stuff is GQ's for shared memory
addr and taddr don't have to be defined any more, so that <sys/mman.h>
can be included for proper prototypes of munmap() and friends.
- rename our GETPID to MINIX_GETPID to avoid a name conflict with
other sources
- PM needs its own munmap() and munmap_text() to avoid sending messages
to VM at the startup phase. It *does* want to do that, but only
after initialising. So they're called again with unmap_ok set to 1
later.
- getnuid(), getngid() implementation
- If allocation of a new buffer fails, use an already-allocated
unused buffer if available (low memory conditions)
- Allocate buffers dynamically, so memory isn't wasted on wrong-sized
buffers.
- No more _MAX_BLOCK_SIZE.
bin_img=1 in the boot monitor will make sure that during the boot procedure the
mfs binary that is part of the boot image is the only binary that is used to
mount partitions. This is useful when for some reason the mfs binary on disk
malfunctions, rendering Minix unable to boot. By setting bin_img=1, the binary
on disk is ignored and the binary in the boot image is used instead.
- 'service' now accepts an additional flag -r. -r implies -c. -r instructs RS
to first look in memory if the binary has already been copied to memory and
execute that version, instead of loading the binary from disk. For example,
the first time a MFS is being started it is copied (-c) to memory and
executed from there. The second time MFS is being started this way, RS will
look in memory for a previously copied MFS binary and reuse it if it exists.
- The mount and newroot commands now accept an additional flag -i, which
instructs them to set the MS_REUSE flag in the mount flags.
- The mount system call now supports the MS_REUSE flag and invokes 'service'
with the -r flag when MS_REUSE is set.
- /etc/rc and the rc script that's included in the boot image check for the
existence of the bin_img flag in the boot monitor, and invoke mount and
newroot with the -i flag accordingly.
- 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.
o Don't call vm_willexit() more than once upon normal process exit
o Correct two cases of indenting of the no-discussion-possible kind
o Perform slightly stricter ptrace(2) checks:
- process calling ptrace must be target process's parent
- process must call wait/waitpid before using ptrace on stopped child
- no ptrace on zombies
o Allow user processes to use ptrace(T_STOP) to stop an active child
Kernel:
o Remove s_ipc_sendrec, instead using s_ipc_to for all send primitives
o Centralize s_ipc_to bit manipulation,
- disallowing assignment of bits pointing to unused priv structs;
- preventing send-to-self by not setting bit for own priv struct;
- preserving send mask matrix symmetry in all cases
o Add IPC send mask checks to SENDA, which were missing entirely somehow
o Slightly improve IPC stats accounting for SENDA
o Remove SYSTEM from user processes' send mask
o Half-fix the dependency between boot image order and process numbers,
- correcting the table order of the boot processes;
- documenting the order requirement needed for proper send masks;
- warning at boot time if the order is violated
RS:
o Add support in /etc/drivers.conf for servers that talk to user processes,
- disallowing IPC to user processes if no "ipc" field is present
- adding a special "USER" label to explicitly allow IPC to user processes
o Always apply IPC masks when specified; remove -i flag from service(8)
o Use kernel send mask symmetry to delay adding IPC permissions for labels
that do not exist yet, adding them to that label's process upon creation
o Add VM to ipc permissions list for rtl8139 and fxp in drivers.conf
Left to future fixes:
o Removal of the table order vs process numbers dependency altogether,
possibly using per-process send list structures as used for SYSTEM calls
o Proper assignment of send masks to boot processes;
some of the assigned (~0) masks are much wider than necessary
o Proper assignment of IPC send masks for many more servers in drivers.conf
o Removal of the debugging warning about the now legitimate case where RS's
add_forward_ipc cannot find the IPC destination's label yet
POSIX compliance.
VFS changes:
* truncate() on a file system mounted read-only no longer panics MFS.
* ftruncate() and fcntl(F_FREESP) now check for write permission on
the file descriptor instead of the file, write().
* utime(), chown() and fchown() now check for file system read-only
status.
MFS changes:
* link() and rename() no longer return the internal EENTERMOUNT and
ELEAVEMOUNT errors to the application as part of a check on the
source path.
* rename() now treats EENTERMOUNT from the destination path check as
an error, preventing file system corruption from renaming a normal
directory to an existing mountpoint directory.
* mountpoints (mounted-on dirs) are hidden better during lookups:
- if a lookup starts from a mountpoint, the first component has to
be ".." (anything else being a VFS-FS protocol violation).
- in that case, the permissions of the mountpoint are not checked.
- in all other cases, visiting a mountpoint always results in
EENTERMOUNT.
* a lookup on ".." from a mount root or chroot(2) root no longer
succeeds if the caller does not have search permission on that
directory.
* POSIX: getdents() now updates directory access times.
* POSIX: readlink() now returns partial results instead of ERANGE.
Miscellaneous changes:
* semaphore file handling bug (leading to hangs) fixed in test 32.
The VFS changes should now put the burden of checking for read-only
status of file systems entirely on VFS, and limit the access
permission checks that file systems have to perform, to checking
search permission on directories during lookups. From this point on,
any deviation from that spceification should be considered a bug.
Note that for legacy reasons, the root partition is assumed to be
mounted read-write.
- Changed VFS-FS protocol to only store OK or negative error code in
m_type field of reply messages.
- Changed VFS to treat nonzero positive replies from FS as requests.
- Added backwards compatibility to VFS and MFS.
No protection of global data structures is provided in VFS, so many
VFS calls cannot be made safely by FS servers during many FS calls.
Use with caution (or, preferably, not at all).
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.
- slight code cleanup
- neater exit procedure: exit when unmount
message received and kill signal (from RS 'down' or
reboot/shutdown) received (speed up unmount, but don't
confuse VFS by exiting before/during unmount msg)
read/write writable in the pagetable right away instead of waiting for
a pagefault. minor optimization.
some a sanity check of SLAB-allocated pointers.
vm gets its own _exit and __exit like PM, so the stock (library) panic works.
- ipc checking code in kernel didn't properly catch the
sendrec() to self case; added special case check
- triggered by PM using stock panic() - needs its own _exit()
reported by Joren l'Ami.
now used for printing diagnostic messages through the kernel message
buffer. this lets processes print diagnostics without sending messages
to tty and log directly, simplifying the message protocol a lot and
reducing difficulties with deadlocks and other situations in which
diagnostics are blackholed (e.g. grants don't work). this makes
DIAGNOSTICS(_S), ASYN_DIAGNOSTICS and DIAG_REPL obsolete, although tty
and log still accept the codes for 'old' binaries. This also simplifies
diagnostics in several servers and drivers - only tty needs its own
kputc() now.
. simplifications in vfs, and some effort to get the vnode references
right (consistent) even during shutdown. m_mounted_on is now NULL
for root filesystems (!) (the original and new root), a less awkward
special case than 'm_mounted_on == m_root_node'. root now has exactly
one reference, to root, if no files are open, just like all other
filesystems. m_driver_e is unused.
. map kernel in non-user
. don't map in first pages of kernel code and data
if possible
these first pages could actually be freed but as the
kernel isn't allowed to touch them either we can't reuse
them until VM has totally taken over page table management
and kernel doesn't rely on identity mapping any more.
their own fully fledged virtual address space and freeing
their pre-allocated heap+stack area (necessary to let memory
driver map in arbitrary areas of memory for /dev/mem without
sys_vm_map)
- small optimization preallocating memory on exec
- finished VR_DIRECT physical mapping code
flag to suspend a process until the filedescriptor is re-opened. Added
dev_reopen, asyn_io, suspended_ep, reopen_reply, asynsend, diag_repl,
close_filp, close_reply, unpause, select_reply1, select_reply2.
. print newline
. when recursive panic detected, don't simply return, confusing
the caller, but print a diagnostic and exit
. don't call sys_exit as this may confuse PM; it should be OK
to call PM exit() nowadays.
case of directories extended by subfilesystem. Rely on subfilesystem to
do read size truncating and return actual i/o size. This fixes bug 81 in
gforge, and unbreaks test 23.
Select now returns such a filedescriptor as ready (instead of EBADF).
Reply before dev_up in FSSIGNON to avoid the problem that a DEV_OPEN
request is received by a driver that expects a reply from the FSSIGNON.
. vfs: 64-bit offset support for character device i/o
(also remove unused dev_bio function)
. memory: /dev/null and /dev/zero are infinitely large, don't stop
reading/writing at 4GB
as a first component of an absolute path failed (e.g. 'touch /file'),
due to leading slashes not being skipped in the processed path counter
in that case, causing create to fail.
bugfixes:
SYSTEM:
. removed
rc->p_priv->s_flags = 0;
for the priv struct shared by all user processes in get_priv(). this
should only be done once. doing a SYS_PRIV_USER in sys_privctl()
caused the flags of all user processes to be reset, so they were no
longer PREEMPTIBLE. this happened when RS executed a policy script.
(this broke test1 in the test set)
VFS/MFS:
. chown can change the mode of a file, and chmod arguments are only
part of the full file mode so the full filemode is slightly magic.
changed these calls so that the final modes are returned to VFS, so
that the vnode can be kept up-to-date.
(this broke test11 in the test set)
MFS:
. lookup() checked for sizeof(string) instead of sizeof(user_path),
truncating long path names
(caught by test 23)
. truncate functions neglected to update ctime
(this broke test16)
VFS:
. corner case of an empty filename lookup caused fields of a request
not to be filled in in the lookup functions, not making it clear
that the lookup had failed, causing messages to garbage processes,
causing strange failures.
(caught by test 30)
. trust v_size in vnode when doing reads or writes on non-special
files, truncating i/o where necessary; this is necessary for pipes,
as MFS can't tell when a pipe has been truncated without it being
told explicitly each time.
when the last reader/writer on a pipe closes, tell FS about
the new size using truncate_vn().
(this broke test 25, among others)
. permission check for chdir() had disappeared; added a
forbidden() call
(caught by test 23)
new code, shouldn't change anything:
. introduced RTS_SET, RTS_UNSET, and RTS_ISSET macro's, and their
LOCK variants. These macros set and clear the p_rts_flags field,
causing a lot of duplicated logic like
old_flags = rp->p_rts_flags; /* save value of the flags */
rp->p_rts_flags &= ~NO_PRIV;
if (old_flags != 0 && rp->p_rts_flags == 0) lock_enqueue(rp);
to change into the simpler
RTS_LOCK_UNSET(rp, NO_PRIV);
so the macros take care of calling dequeue() and enqueue() (or lock_*()),
as the case may be). This makes the code a bit more readable and a
bit less fragile.
. removed return code from do_clocktick in CLOCK as it currently
never replies
. removed some debug code from VFS
. fixed grant debug message in device.c
preemptive checks, tests, changes:
. added return code checks of receive() to SYSTEM and CLOCK
. O_TRUNC should never arrive at MFS (added sanity check and removed
O_TRUNC code)
. user_path declared with PATH_MAX+1 to let it be null-terminated
. checks in MFS to see if strings passed by VFS are null-terminated
IS:
. static irq name table thrown out
. changed umount() and mount() to call 'service', so that it can include
a custom label, so that umount() works again (RS slot gets freed now).
merged umount() and mount() into one file to encode keep this label
knowledge in one file.
. removed obsolete RS_PID field and RS_RESCUE rescue command
. added label to RS_START struct
. vfs no longer does kill of fs process on unmount (which was failing
due to RS_PID request not working)
. don't assume that if error wasn't one of three errors, that no error
occured in vfs/request.c
mfs changes:
. added checks to copy statements to truncate copies at buffer sizes
(left in debug code for now)
. added checks for null-terminatedness, if less than NAME_MAX was copied
. added checks for copy function success
is changes:
. dump rs label
drivers.conf changes:
. added acl for mfs so that mfs can be started with 'service start',
so that a custom label can be provided
print debug message if copy is truncated
. increased buffer in lookup() to be PATH_MAX instead of NAME_MAX
. sanity check in fetch_name() in vfs to see if name fits, and
is null-terminated
. first check i < NAME_MAX, then string[i] in search_dir, as we're
not supposed to look at string[NAME_MAX]
. corrected device match for unmount (otherwise unmount would
proceed with bogus mount slot, often sending messages to 0 (PM))
. added some sanity checking to fs process number
. made fs_sendrec PRIVATE to request.c
mainly in the kernel and headers. This split based on work by
Ingmar Alting <iaalting@cs.vu.nl> done for his Minix PowerPC architecture
port.
. kernel does not program the interrupt controller directly, do any
other architecture-dependent operations, or contain assembly any more,
but uses architecture-dependent functions in arch/$(ARCH)/.
. architecture-dependent constants and types defined in arch/$(ARCH)/include.
. <ibm/portio.h> moved to <minix/portio.h>, as they have become, for now,
architecture-independent functions.
. int86, sdevio, readbios, and iopenable are now i386-specific kernel calls
and live in arch/i386/do_* now.
. i386 arch now supports even less 86 code; e.g. mpx86.s and klib86.s have
gone, and 'machine.protected' is gone (and always taken to be 1 in i386).
If 86 support is to return, it should be a new architecture.
. prototypes for the architecture-dependent functions defined in
kernel/arch/$(ARCH)/*.c but used in kernel/ are in kernel/proto.h
. /etc/make.conf included in makefiles and shell scripts that need to
know the building architecture; it defines ARCH=<arch>, currently only
i386.
. some basic per-architecture build support outside of the kernel (lib)
. in clock.c, only dequeue a process if it was ready
. fixes for new include files
files deleted:
. mpx/klib.s - only for choosing between mpx/klib86 and -386
. klib86.s - only for 86
i386-specific files files moved (or arch-dependent stuff moved) to arch/i386/:
. mpx386.s (entry point)
. klib386.s
. sconst.h
. exception.c
. protect.c
. protect.h
. i8269.c
as living processes before they are cleaned up (fixes
wait()/waitpid() hanging forever on previously-ZOMBIE processes)
. stop processes from running using sys_nice() with PRIO_STOP
when a handled signal is delivered, before computing
stack locations for sys_sigsend(). (fixes race condition
when runnable processes get signals, and e.g. get scheduled
before FS sends a reply to unpause(), which can make the
signal stack location wrong.)
-script argument to service for crash recovery scripts
-config argument to service for driver resource configuration
restart command in service to restart a driver after a crash (for use in
crash recovery scripts).
down and refresh now take labels instead of pids.
verious changes in rs to make this work.
argument from the fd bitmasks are copied from and back to userspace. This
solves an ABI dependency on OPEN_MAX. If nfds is too big for the current
OPEN_MAX, select() fails (but that's relatively easy to fix by 'just'
recompiling the system and not the application binaries), but if it's
smaller, binaries keep working.
size field. The TIOCSFON ioctl size (8192) didn't get encoded properly,
as there weren't enough bits for it (12) in the regular format.
The new format has only one type field, and an extra flag (_IOC_BIG)
turned on. FS checks for this flag and uses the alternative decoding
of the ioctl codes to determine the size when doing grants.
This unbreaks loadfont, although that still uses a phys copy in tty.
form. Subscriptions are regular expressions.
. different types are stored per key; currently u32 and/or string.
the same key can be referenced (publish, subscribe, check) as any type.
. notify()s are sent when subscriptions are triggered (publishing or
updating of matching keys); optionally, a subscribe flag sends
updates for all matching keys at subscription time, instead of only
after updates after subscribing
. all interfacing to ds is in /usr/src/lib/syslib/ds.c.
. subscribe is ds_subscribe
publish functions are ds_publish_<type>
retrieve functions are ds_retrieve_<type> (one-time retrieval of a value)
check functions are ds_check_<type> (check for updated key caller
subscribes to not yet checked for, or ESRCH for none)
. ramdisk driver updated with new ds interface
