unwind: disable stack trace with multiple personalities

* unwind.c (unwind_cache_invalidate, unwind_print_stacktrace,
unwind_capture_stacktrace): Disable stack tracing of non-default
personality processes.
unwind: constify binary_filename and symbol_name functions arguments

* unwind.c (call_action_fn, print_call_cb, sprint_call_or_error,
queue_put, queue_put_call): Add const qualifier to binary_filename and
symbol_name arguments.
unwind: refactor stacktrace_walk

* unwind.c (stacktrace_walk): Move stack frame printing code
to separate function print_stack_frame.
unwind: remove unused field from mmap_cache_t

* unwind.c (mmap_cache_t): Remove "deleted" field.
(build_mmap_cache): Remove initialization of "deleted" field.
unwind: cleanup build_mmap_cache

* unwind.c (build_mmap_cache): Move local variables to the code branch
where they are used.  Check return code of sscanf and strdup.  Do not
treat unusual memory mappings as fatal errors.  Do not skip memory
mappings with path names starting with "[".
unwind: ignore memory mappings that have no PROT_EXEC bit set

* unwind.c (build_mmap_cache): For each memory mapping being scanned,
save its PROT_EXEC bit and skip the mapping if it is not set.
tests: enhance -k test

Add two more function calls to the stack.  Suggested by Masatake YAMATO.

* tests/stack-fcall.c (f1): Rename to f3.
(f1, f2): New functions.
* tests/strace-k.test: Update.
tests: robustify -k test

Split stack-fcall.c into several compilation units so that intermediate
function calls would not be optimized out by compiler.

* tests/stack-fcall.c: Move intermediate functions to ...
* tests/stack-fcall-*.c: ... new files.
* tests/Makefile.am (stack_fcall_SOURCES): Add stack-fcall-*.c.
Document -k option as experimental

strace -k does not produce a reliable output on all supported
configurations yet, even basic strace-k.test is known to fail
on some of them.

* strace.c (usage): Document -k option as experimental.
* strace.1: Likewise.
* NEWS: Likewise.
xtensa: sort values in struct_user_offsets

Otherwise ptrace syscall argument decoding is wrong:
  ptrace(PTRACE_PEEKUSER, 296, syscall_nr, [0x4048eb]) = 0
  ptrace(PTRACE_PEEKUSER, 296, syscall_nr, [0x3fa6cd30]) = 0
  ptrace(PTRACE_PEEKUSER, 296, syscall_nr, [0x8040676d]) = 0
instead of
  ptrace(PTRACE_PEEKUSER, 296, pc, [0x4048eb]) = 0
  ptrace(PTRACE_PEEKUSER, 296, a1, [0x3fa6cd30]) = 0
  ptrace(PTRACE_PEEKUSER, 296, a0, [0x8040676d]) = 0

* process.c (struct_user_offsets) [XTENSA]: Sort values.
Merge remote-tracking branch 'strace/master' into HEAD
Merge changes Icedbb451,I57fac759,I2734a701,Ib0764206,Ic588b205, ...

* changes:
  Merge remote-tracking branch 'strace/master' into HEAD
  xtensa: sort values in struct_user_offsets
  Document -k option as experimental
  tests: robustify -k test
  tests: enhance -k test
  unwind: ignore memory mappings that have no PROT_EXEC bit set
  unwind: cleanup build_mmap_cache
  unwind: remove unused field from mmap_cache_t
  unwind: refactor stacktrace_walk
  unwind: constify binary_filename and symbol_name functions arguments
  unwind: disable stack trace with multiple personalities
x32: update io_{setup,submit} syscalls

Starting in 3.16, these two syscalls have gotten their own entry
point for x32.  See linux 7fd44dacdd803c0bbf38bf478d51d280902bb0f1.

* linux/x32/syscallent.h: Change existing io_{setup,submit} to 64bit,
and add new entry points for x32 specifically.
Decode file descriptors returned by accept and accept4 syscalls

* net.c (do_accept): Rename to do_sockname.
(sys_accept, sys_accept4): Update callers, return RVAL_FD.
(sys_getsockname, sys_getpeername): Call do_sockname directly.
* tests/net-fd.test: Update.
Fix preadv/pwritev offset decoding on bigendian architectures

This partially reverts commit 7845a42b39e59e904d01e75e21f7bc7eb6462560.

* util.c (printllval): Remove align argument.
* defs.h (printllval): Update prototype.
(printllval_aligned, printllval_unaligned): Remove.
* file.c (sys_readahead, sys_truncate64, sys_ftruncate64, sys_fadvise64,
sys_fadvise64_64, sys_sync_file_range, sys_sync_file_range2,
sys_fallocate): Replace printllval_aligned call with printllval.
* io.c (sys_pread, sys_pwrite): Likewise.
(print_llu_from_low_high_val): New function.
(sys_preadv, sys_pwritev): Use it instead of printllval_unaligned.
Fix preadv/pwritev offset decoding on ILP32 architectures

This fixes regression introduced by the previous commit.

* io.c (print_llu_from_low_high_val) [SIZEOF_LONG != SIZEOF_LONG_LONG]:
Cast argument to unsigned long before casting it to unsigned long long.
Prepare for -yy option support

* defs.h (show_fd_path): Change type to unsigned int.
* strace.c (show_fd_path): Likewise.
(init): Handle repeated -y option.
alpha: fix sigaction decoding

Since the rt_sigaction syscall on alpha doesn't have a sa_restorer,
do not include it in the kernel struct.

* signal.c (struct new_sigaction): Disable sa_restorer on alpha.
hppa: fix sigaction decoding

Since the rt_sigaction syscall on hppa doesn't have a sa_restorer,
do not include it in the kernel struct.

We also have to undefine SA_RESTORER so that code doesn't try to
use it.  The headers will export this, but the syscall doesn't
actually respect it.

* signal.c (SA_RESTORER): Undefine when HPPA is defined.
(struct new_sigaction): Disable sa_restorer on hppa.
alpha/sparc: fix arg count for rt_sigaction

Both these arches have a rt_sigaction syscall that takes 5 args, not 4.

* linux/alpha/syscallent.h (rt_sigaction): Change nargs to 5.
* linux/sparc/syscallent.h (rt_sigaction): Change nargs to 5.