After the commit 93508e5bb8, the access permissions argument passed
to open_shared() is ignored and always replaced with (FILE_MAP_READ |
FILE_MAP_WRITE). This causes the weird behaviour that sshd service
process loses its cygwin PID. This triggers the failure in pty that
transfer_input() does not work properly.
This patch resumes the access permission settings to fix that.
Fixes: 93508e5bb8 ("Cygwin: open_shared: don't reuse shared_locations parameter as output")
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signedd-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
2f9b8ff0 introduced a problem where forks would sometimes fail with:
child_copy: cygheap read copy failed, 0x0..0x80044C750, done 0, windows pid 14032, Win32 error 299
When cygheap_max was > CYGHEAP_STORAGE_INITIAL, commit_size would be set to
allocsize(cygheap_max), which is an address, not a size. VirtualAlloc would be
called to commit commit_size bytes, which would fail, and then child_copy would
be called with zero as the base address.
Fixes: 2f9b8ff00c ("Cygwin: decouple cygheap from Cygwin DLL")
Signed-off-by: David McFarland <corngood@gmail.com>
Eventually move user heap initialization to memory_init.
The call order is not changed. Drop a now useless comment.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The new loop in open_shared has a subtil performance problem.
Next_address is bumped only if mapping at this address
failed. Every subsequent call to open_shared has a high probability
having to call MapViewOfFileEx twice, because next_address is still
set to the address of the last successful mapping.
Avoid this by bumping next_address every time.
While at it, fix a comment.
Fixes: dc0fe7742b ("Cygwin: open_shared: try harder allocating a shared region")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
With the previous commit 9ddd48ee1b ("Cygwin: /proc/<PID>/maps:
print real shared region addresses"), the real addresses of
the standard shared regions (cygwin, user, myself, shared console)
are read from the printed process itself. We don't need fixed
addresses anymore, so drop the definitions and simplify open_shared.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far, the addresses printed for the shared regions of a process
were faked. The assumption was that the shared regions are always
in the same place in all processes, so we just printed the addresses
of the current process. This is no safe bet. The only safe bet is
the address of the cygheap. So keep track of the addresses in the
cygheap and read the addresses from the cygheap of the observed
processes. Add output for the shared console.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
For fixed regions (cygwin/user/myself/shared console), try fixed
address first. Fallback to non-fixed region. Don't even try fixed
address if the Cygwin DLL gets dynamically loaded.
For non-fixed regions, try to allocate in a loop within the area
from SHARED_REGIONS_ADDRESS_LOW to SHARED_REGIONS_ADDRESS_HIGH.
Fixes: 60675f1a7e ("Cygwin: decouple shared mem regions from Cygwin DLL")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Fix comments accordingly.
This is in preparation for a change in open_shared, handling shared
regions more cleanly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
For ages, open_shared uses the shared_locations parameter as
output to indicate if the mapping for a shared region has been
created or just opened. Split this into two parameters. Use
the shared_locations parameter as input only, return the creation
state of the mapping in a bool reference parameter.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
After the commit 30add3e6b3, the problem:
https://cygwin.com/pipermail/cygwin/2022-December/252759.html
occurs rarely. It seems that myself_pinfo should be initialized
where the timing before child_copy() and after cygheap allocation.
This patch moves the initialization there.
Fixes: 30add3e6b3 ("Cygwin: exec: don't access cygheap before it's
initialized")
Reported-by: Brian Inglis <Brian.Inglis@Shaw.ca>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
POSIX states "A terminal may be the controlling terminal for at most
one session."
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap11.html
However, in cygwin, multiple sessions could be associated with the
same TTY. This patch aligns CTTY behavior to the statement of POSIX.
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
Every time the cygheap is initialized, that is, on each fork
or exec, cygheap_init() *again* computes the bucket size values
and stores them in the cgyheap, albeit they are always the
same values anyway.
Make bucket_val a local const array, statically initialized
instead.
Fixes: 61522196c7 ("* Merge in cygwin-64bit-branch.)"
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Another reason ASLR may fail is the coupling of the standard shared
mem regions (global, userinfo, process info, shared console) to the
address of the Cygwin DLL. They are always placed in fixed addresses
preceeding the Cygwin DLL's address. With ASLR this is bound to fail.
Use a fixed, unused memory area to place the shared mem regions.
This also allows to simplify the shared memory creation. There's
no reason anymore to rebase the regions and rather than offsets,
just use the addresses directly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
One reason that ASLR is tricky is the fact that the cygheap
is placed at the end of the DLL and especially that it's expected
to be growable. To support ASLR, this construct must go.
Define dedicated cygheap memory region and reserve entire region.
Commit 3 Megs, as was the default size of the cygheap before.
Fix linker script accordingly, drop a now useless version check
in get_cygwin_startup_info().
Collect all info about memory layout in one header file, so
the mem layout is documented in one logical place and not
in heap.cc arbitrarily.
Use info from this file throughout.
This is to prepare for ASLR support.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Takashi Yano
David McFarland
Corinna Vinschen