Should fix PR/36939 and make the rlimit code MP safe.
Posted for comment to tech-kern (non received!)
The p_limit field (for a process) is only be changed once (on the first
write), and a reference to the old structure is kept (for code paths
that have cached the pointer).
Only p->p_limit is now locked by p->p_mutex, and since the referenced memory
will not go away, is only needed if the pointer is to be changed.
The contents of 'struct plimit' are all locked by pl_mutex, except that the
code doesn't bother to acquire it for reads (which are basically atomic).
Add FORK_SHARELIMIT that causes fork1() to share the limits between parent
and child, use it for the IRIX_PR_SULIMIT.
Fix borked test for both IRIX_PR_SUMASK and IRIX_PR_SDIR being set.
Possibly the standard nfs code needs teaching how to set the length and
address family in order to support non-netbsd sockaddr.
There are now no active stackgap() calls in the compat tree.
and 'rusage' without having to copy data to/from stackgap buffers.
The old split (find_stopped_child) could be removed.
amd64 seems to run netbsd32, linux and linux32 emulations. sparc64 compiles.
avoid having to allocate space in the 'stackgap'
- which is very LWP unfriendly.
The additional code for non-emulation namei() is trivial, the reduction for
the emulations is massive.
The vnode for a processes emulation root is saved in the cwdi structure
during process exec.
If the emulation root the TRYEMULROOT flag are set, namei() will do an initial
search for absolute pathnames in the emulation root, if that fails it will
retry from the normal root.
".." at the emulation root will always go to the real root, even in the middle
of paths and when expanding symlinks.
Absolute symlinks found using absolute paths in the emulation root will be
relative to the emulation root (so /usr/lib/xxx.so -> /lib/xxx.so links
inside the emulation root don't need changing).
If the root of the emulation would be returned (for an emulation lookup), then
the real root is returned instead (matching the behaviour of emul_lookup,
but being a cheap comparison here) so that programs that scan "../.."
looking for the root dircetory don't loop forever.
The target for symbolic links is no longer mangled (it used to get the
CHECK_ALT_xxx() treatment, so could get /emul/xxx prepended).
CHECK_ALT_xxx() are no more. Most of the change is deleting them, and adding
TRYEMULROOT to the flags to NDINIT().
A lot of the emulation system call stubs could now be deleted.
sys_stat() and friends, instead use do_sys_stat() and do_sys_fstat()
that write the answer into a kernel buffer (on stack) that can be
converted to the correct form and written the userspace.
I've test compiled a few kernels, and tested i386 netbsd1.6 ls.
Given I think I've fixed some bugs, it might be 50-50 with new ones.
process was reparented. Change proc_free() to copy the rusage to a buffer
on the stack if required, so it can be passed both to the debugger and
to the real parent process.
Fixes kern/35582 (kernel panics with gdb).
- use vmspace rather than proc or lwp where appropriate.
the latter is more natural to specify an address space.
(and less likely to be abused for random purposes.)
- fix a swdmover race.
* For sparc64 and amd64, define *SIZ32 VM constants.
* Add a new function pointer to struct emul, pointing at a function
that will return the default VM map address. The default function
is uvm_map_defaultaddr, which just uses the VM_DEFAULT_ADDRESS
macro. This gives emulations control over the default map address,
and allows things to be mapped at the right address (in 32bit range)
for COMPAT_NETBSD32.
* Add code to adjust the data and stack limits when a COMPAT_NETBSD32
or COMPAT_SVR4_32 binary is executed.
* Don't use USRSTACK in kern_resource.c, use p_vmspace->vm_minsaddr
instead (emulations might have set it differently)
* Since this changes struct emul, bump kernel version to 3.99.2
Tested on amd64, compile-tested on sparc64.
he