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.
