bits/sigstack.h contains four things: the legacy struct sigstack type,
the preferred stack_t type, the SS_* enum values and macros for signal
stack sizes.
These vary in different ways between glibc configurations; in
particular, the stack sizes vary much more than any of the other
pieces. Furthermore, these pieces have different standard namespace
rules for when they should be visible (not currently visible in
conform/ results both because the relevant tests are XFAILed for
sys/ucontext.h namespace issues, and because some of the expectations
are incorrect in the same way as the headers, e.g. neither
expectations nor headers reflect that current POSIX no longer has
either the sigstack function or the sigstack structure).
To reduce duplication of identical definitions, and facilitate
namespace fixes without requiring the same feature test macro
conditions to be repeated in many versions of the same header, this
patch splits bits/sigstack.h up into four headers. It keeps the stack
size macros, while new bits/types/struct_sigstack.h,
bits/types/stack_t.h and bits/ss_flags.h are added for the other
pieces. bits/types/struct_sigstack.h is the same everywhere,
bits/types/stack_t.h has three variants different in the order of the
structure elements (generic = MIPS Linux, and other Linux), and
bits/ss_flags.h has generic and Linux variants.
This patch includes the new headers everywhere that included
<bits/sigstack.h>, so should cause no difference to what any public
header defines. Subsequent namespace fixes would then remove or
condition some of those includes.
There should be no conflicts with Zack's changes to signal.h types,
beyond the trivial conflict of both making additions to
signal/Makefile's headers list; the two patches affect disjoint sets
of types and other definitions.
Tested for x86_64 and x86, and with build-many-glibcs.py.
* bits/ss_flags.h: New file.
* bits/types/stack_t.h: Likewise.
* include/bits/types/struct_sigstack.h: Likewise.
* signal/bits/types/struct_sigstack.h: Likewise.
* sysdeps/unix/sysv/linux/bits/ss_flags.h: Likewise.
* sysdeps/unix/sysv/linux/bits/types/stack_t.h: Likewise.
* sysdeps/unix/sysv/linux/mips/bits/types/stack_t.h: Likewise.
* signal/Makefile (headers): Add bits/types/struct_sigstack.h,
bits/types/stack_t.h and bits/ss_flags.h.
* signal/signal.h [__USE_XOPEN_EXTENDED || __USE_XOPEN2K8]:
Include <bits/types/struct_sigstack.h>, <bits/types/stack_t.h> and
<bits/ss_flags.h>.
* bits/sigstack.h (struct sigstack): Remove.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/aarch64/bits/sigstack.h
(struct sigstack): Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/alpha/bits/sigstack.h (struct sigstack):
Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/bits/sigstack.h (struct sigstack):
Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/mips/bits/sigstack.h: Likewise.
* sysdeps/unix/sysv/linux/ia64/bits/sigstack.h (struct sigstack):
Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/powerpc/bits/sigstack.h
(struct sigstack): Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/unix/sysv/linux/sparc/bits/sigstack.h (struct sigstack):
Likewise.
(stack_t): Likewise.
(SS_ONSTACK): Likewise.
(SS_DISABLE): Likewise.
* sysdeps/arm/sys/ucontext.h: Include
<bits/types/struct_sigstack.h>, <bits/types/stack_t.h> and
<bits/ss_flags.h>.
* sysdeps/generic/sys/ucontext.h: Likewise.
* sysdeps/i386/sys/ucontext.h: Likewise.
* sysdeps/m68k/sys/ucontext.h: Likewise.
* sysdeps/mips/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/arm/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/hppa/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/ia64/bits/sigcontext.h: Likewise.
* sysdeps/unix/sysv/linux/ia64/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/mips/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/s390/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/sh/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/tile/sys/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/x86/sys/ucontext.h: Likewise.
sys/ucontext.h unconditionally uses stack_t, and it does not make
sense to change that. But signal.h only declares stack_t under
__USE_XOPEN_EXTENDED || __USE_XOPEN2K8. The actual definition is
already in a bits header, bits/sigstack.h, but that header insists on
only being included by signal.h, so we have to change that as well as
all of the sys/ucontext.h variants. (Some but not all variants of
bits/sigcontext.h, which sys/ucontext.h may also need, had already
received this adjustment; for consistency, I made them all the same,
even if that's not strictly necessary in some configurations.)
bits/sigcontext.h and bits/sigstack.h also all need to receive
multiple inclusion guards.
* sysdeps/generic/sys/ucontext.h
* sysdeps/arm/sys/ucontext.h
* sysdeps/i386/sys/ucontext.h
* sysdeps/m68k/sys/ucontext.h
* sysdeps/mips/sys/ucontext.h
* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h
* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
* sysdeps/unix/sysv/linux/arm/sys/ucontext.h
* sysdeps/unix/sysv/linux/hppa/sys/ucontext.h
* sysdeps/unix/sysv/linux/ia64/sys/ucontext.h
* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
* sysdeps/unix/sysv/linux/mips/sys/ucontext.h
* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
* sysdeps/unix/sysv/linux/s390/sys/ucontext.h
* sysdeps/unix/sysv/linux/sh/sys/ucontext.h
* sysdeps/unix/sysv/linux/sparc/sys/ucontext.h
* sysdeps/unix/sysv/linux/tile/sys/ucontext.h
* sysdeps/unix/sysv/linux/x86/sys/ucontext.h:
Include both bits/sigcontext.h and bits/sigstack.h.
Fix grammar error in comment, if present.
* bits/sigstack.h
* sysdeps/unix/sysv/linux/aarch64/bits/sigstack.h
* sysdeps/unix/sysv/linux/alpha/bits/sigstack.h
* sysdeps/unix/sysv/linux/bits/sigstack.h
* sysdeps/unix/sysv/linux/ia64/bits/sigstack.h
* sysdeps/unix/sysv/linux/mips/bits/sigstack.h
* sysdeps/unix/sysv/linux/powerpc/bits/sigstack.h
* sysdeps/unix/sysv/linux/sparc/bits/sigstack.h
* bits/sigcontext.h
* sysdeps/mach/hurd/i386/bits/sigcontext.h
* sysdeps/unix/sysv/linux/bits/sigcontext.h
* sysdeps/unix/sysv/linux/ia64/bits/sigcontext.h
* sysdeps/unix/sysv/linux/sparc/bits/sigcontext.h:
Add multiple inclusion guard. Permit inclusion by sys/ucontext.h
as well as signal.h, if this was not already allowed. Request
definition of size_t if necessary. Minimize semantically-null
differences across files.
http://sourceware.org/ml/libc-alpha/2013-08/msg00093.html
This copies the sparc version of sigstack.h, which gives powerpc
#define MINSIGSTKSZ 4096
#define SIGSTKSZ 16384
Before the VSX changes, struct rt_sigframe size was 1920 plus 128 for
__SIGNAL_FRAMESIZE giving ppc64 exactly the default MINSIGSTKSZ of
2048.
After VSX, ucontext increased by 256 bytes. Oops, we're over
MINSIGSTKSZ, so powerpc has been using the wrong value for quite a
while. Add another ucontext for TM and rt_sigframe is now at 3872,
giving actual MINSIGSTKSZ of 4000.
The glibc testcase that I was looking at was tst-cancel21, which
allocates 2*SIGSTKSZ (not because the test is trying to be
conservative, but because the test actually has nested signal stack
frames). We blew the allocation by 48 bytes when using current
mainline gcc to compile glibc (le ppc64).
The required stack depth in _dl_lookup_symbol_x from the top of the
next signal frame was 10944 bytes. I guess you'd want to add 288 to
that, implying an actual SIGSTKSZ of 11232.
* sysdeps/unix/sysv/linux/powerpc/bits/sigstack.h: New file.
