ARM: fix sigreturn decoding

Decoding of test/sigreturn testcase:
Was:
sigreturn() (mask [QUIT TRAP ABRT BUS SEGV USR2 PIPE STKFLT STOP XCPU VTALRM PROF WINCH IO PWR RTMIN]) = 0
Now:
sigreturn() (mask [CHLD RT_1 RT_3 RT_31 RT_32]) = 0

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
ARM: remove wrong NSIG = 32 define

ARM in fact has 64 signals (1..64), and NSIG should be 65
(as usual, rememebr that NSIG_libc == NSIG_kernel+1).

I carefully reviewed all usages of NSIG. In syscall.c,
the only usage is:
        for (i = 0; i <= NSIG; i++)
                if (strcasecmp(s, signame(i) + 3) == 0)...
which is safe even if NSIG is way too big - signame(i)
returns a well-formed string for any i.

In signal.c, memcpy(&sigset, &sc.sc_mask, NSIG / 8) is used by
IA64 and TILE code, so ARM change can't affect it. And final
usage is:
 struct new_sigaction::unsigned long sa_mask[NSIG / sizeof(long)];
It will grow on ARM (and become correct in the process).
Its only use is
 memcpy(&sigset, &sa.sa_mask, NSIG / 8);
 printsigmask(&sigset, 1);
which used to copy garbage in high bits, now it will copy actual data.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
sys_rt_sigaction: fix sigset copying

In practice, we always copy as many bytes as syscall param says
(8, or 16 on mips). However, malicious program can call sigaction
with wrong sigset size. Such syscall will result in EINVAL,
but we (strace) end up copying 128 bytes (sizeof(sigset_t)),
which copyes some garbage from stack after struct sigaction.

Now we always copy NSIG / 8 bytes (which is 8 bytes, or 16 on mips).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Fix sigset printing via print_sigset().

Replace print_sigset() with print_sigset_addr_len(),
which takes not only addr, but also len parameter.
This allows us to drop "do we need to print RT signals?" parameter,
and this fixes RT signals printing in many syscalls.

sys_epoll_pwait: print RT signals too, print sigmask size argument.

sys_sigprocmask: print_sigset -> print_sigset_addr_len(current_wordsize),
no change in functionality.

sys_sigpending: use print_sigset_addr_len(current_wordsize)
instead of open-coding it.

sys_rt_sigprocmask: use print_sigset_addr_len instead of open-coding it.
sys_rt_sigpending: ditto.
sys_rt_sigsuspend: ditto.
sys_rt_sigtimedwait: ditto.

do_signalfd: print_sigset -> print_sigset_addr_len. This fixes
RT signals printing (wasn't showing them before).

sys_ppoll: ditto.

copy_sigset_len() is folded into its only user, print_sigset_addr_len(),
and copy_sigset() is gone.

While at it, checked kernel sources and noted where kernel enforces
sigset_size == NSIG / 8 (== sizeof(kernel_sigset_t)),
and where it allows word-sized sigset_size ([rt_]sigpending).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
I386: fix signedness mismatch warning

&i386_regs.esp is a pointer to long, not unsigned long.
It needs a cast.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Add compat support for sys_pselect6

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Simplify some sigmask manipulations

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Convert some uses of long_to_sigmask+printsigmask to sprintsigmask_long

This allows to drop long_to_sigmask function,
and a whole bunch of sigset_t variables.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Remove rt parameter from [s]printsigmask()

In almost all cases, the parameter was 1 ("decode RT sigs too").
This change hardwires it to be 1.

The cases where it was 0 are, and why the change to "decode RT sigs too"
is fine:

IA64: 64-bit arch, all 64 signals fit in one word in any case.
S390[x]: sc.oldmask is a sigset_t on kernel side,
	(sigset_t *)&sc.oldmask[0] does contain all 64 signals.
TILE: uc.uc_sigmask is a sigset_t on kernel side,
	memcpy(&sigm, &uc.uc_sigmask, NSIG / 8) copies all 64 signals.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>