changes in MD code are trivial, before this change, trapsignal and
sendsig use discrete parameters, now they uses member fields of
ksiginfo_t structure. For sendsig, this change allows us to pass
POSIX realtime signal value to user code.
2. Remove cpu_thread_siginfo, it is no longer needed because we now always
generate ksiginfo_t data and feed it to libpthread.
3. Add p_sigqueue to proc structure to hold shared signals which were
blocked by all threads in the proc.
4. Add td_sigqueue to thread structure to hold all signals delivered to
thread.
5. i386 and amd64 now return POSIX standard si_code, other arches will
be fixed.
6. In this sigqueue implementation, pending signal set is kept as before,
an extra siginfo list holds additional siginfo_t data for signals.
kernel code uses psignal() still behavior as before, it won't be failed
even under memory pressure, only exception is when deleting a signal,
we should call sigqueue_delete to remove signal from sigqueue but
not SIGDELSET. Current there is no kernel code will deliver a signal
with additional data, so kernel should be as stable as before,
a ksiginfo can carry more information, for example, allow signal to
be delivered but throw away siginfo data if memory is not enough.
SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
not be caught or masked.
The sigqueue() syscall allows user code to queue a signal to target
process, if resource is unavailable, EAGAIN will be returned as
specification said.
Just before thread exits, signal queue memory will be freed by
sigqueue_flush.
Current, all signals are allowed to be queued, not only realtime signals.
Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64
o change the mapping arrays to have a zero offset rather than base 1;
this eliminates lots of signo adjustments and brings the code
back inline with the original netbsd code
o purge use of SVR4_SIGTBLZ; SVR4_NSIG is the only definition for
how big a mapping array is
o change the mapping loops to explicitly ignore signal 0
o purge some bogus code from bsd_to_svr4_sigset
o adjust svr4_sysentvec to deal with the mapping table change
Enticed into fixing by: Coverity Prevent analysis tool
Glanced at by: marcel, jhb
syscall compare against a variable sv_minsigstksz in struct
sysentvec as to properly take the size of the machine- and
ABI dependent struct sigframe into account.
The SVR4 and iBCS2 modules continue to have a minsigstksz of
8192 to preserve behavior. The real values (if different) are
not known at this time. Other ABI modules use the real
values.
The native MINSIGSTKSZ is now defined as follows:
Arch MINSIGSTKSZ
---- -----------
alpha 4096
i386 2048
ia64 12288
Reviewed by: mjacob
Suggested by: bde
of 4 longs used as a bitmask. sv4r4_sigfillset has been broken for a
while, probably since rev 1.5.
This patch fixes SVR4_NSIG (i.e.: sets it to the actual number of signals,
instead of the number of bits in the mask) because some SysVR4 clients
honestly seem to care about whether bits in the signal mask are set for
non-existant signals.
Additionally, the svr4_sigfillset macro has been replaced by a
fully fledged function, because the macro didn't actually work
(it returned an all-ones mask, but we don't want that: we want 0's
set where FreeBSD doesn't actually have a signal which is the same
as an SysVR4 signal, for example).
SysVR4 clients can now successfully ignore signals, although catching
them remains problematic (see commit log message for rev1.13 of
sys/i386/svr4/svr4_machdep.c for more info).
-----------------------------
The compatibility code and/or emulators have been updated:
iBCS2 now mostly uses the older syscalls. SVR4 now properly
handles all signals. This has been achieved by using the
new sigset_t throughout the emulator. The Linuxulator has
been severely updated. Internally the new Linux sigset_t is
made the default. These are then mapped to and from the
new FreeBSD sigset_t.
Also, rt_sigsuspend has been implemented in the Linuxulator.
Implementing this syscall basicly caused all this sigset_t
changing in the first place and the syscall has been used
throughout the change as a means for testing. It basicly is
too much work to undo the implementation so that it can
later be added again.
A special note on the use of sv_sigtbl and sv_sigsize in
struct sysentvec:
Every signal larger than sv_sigsize is not translated and is
passed on to the signal handler unmodified. Signals in the
range 1 upto and including sv_sigsize are translated.
The rationale is that only the system defined signals need to
be translated.
The emulators also have been updated so that the translation
tables are only indexed for valid (system defined) signals.
This change also fixes the translation bug already in the
SVR4 emulator.
