Rename sys/ucontext.h to bits/ucontext.h.zack/no-nested-includes

sys/ucontext.h is effectively a bits header.  Its contents are
extremely system-specific, and it’s strongly associated with a
specific public header (ucontext.h) that provides a superset of its
definitions, but there are other public headers that also require some
of its definitions.  This patch therefore moves it into the bits/
namespace and adjusts all the headers that refer to it.  In case there
are external users, a stub is added that includes ucontext.h.

Most of the fallout changes are trivial, but aarch64, ia64 and riscv
need a little more work.  aarch64 sys/ucontext.h (now bits/ucontext.h)
was including sys/procfs.h for the definition of elf_greg_t etc;
the simplest fix is to have it include bits/procfs.h instead (and then
that needs to include sys/user.h for user_regs_struct).  This is not
ideal but fixing it properly would require disentangling all of the
debugger interface headers which is more than I’m up for at the moment.

ia64 bits/ptrace.h and bits/procfs.h were both including
bits/sigcontext.h, which is only licensed to be included from
signal.h.  (I’m not sure how this ever worked, or why it broke with
this patch and not some previous one.)  This is fixed by creating
another single-type header, bits/types/__ia64_fpreg.h, which provides
the only thing they need from bits/sigcontext.h.

s/u/s/l/riscv/makecontext.c was defining makecontext with a function
head that didn’t agree with its official prototype (in ucontext.h);
formerly that file did not include ucontext.h, only sys/ucontext.h,
so we were getting away with it, but it’s still wrong.  Making the
function head match the prototype actually simplifies the code.

	* sysdeps/generic/sys/ucontext.h: Move to top level bits/ucontext.h.
	Adjust multiple inclusion guard.
	* sysdeps/arm/sys/ucontext.h: Move to sysdeps/arm/bits/ucontext.h.
	Adjust multiple inclusion guard.
	* sysdeps/i386/sys/ucontext.h: Similarly.
	* sysdeps/m68k/sys/ucontext.h: Similarly.
	* sysdeps/mips/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/arm/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/csky/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/hppa/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/ia64/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/microblaze/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/mips/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/riscv/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/s390/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/sparc/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/x86/sys/ucontext.h: Similarly.
	* stdlib/Makefile: Install bits/ucontext.h.

	* stdlib/sys/ucontext.h: New backward compatibility stub header,
	includes ucontext.h.
	* include/sys/ucontext.h: New wrapper.

	* sysdeps/unix/sysv/linux/aarch64/bits/procfs.h: Allow inclusion
	by bits/ucontext.h as well as sys/procfs.h.  Include sys/user.h.
	* sysdeps/unix/sysv/linux/aarch64/bits/ucontext.h: Include
	bits/procfs.h instead of sys/procfs.h.

	* sysdeps/unix/sysv/linux/ia64/bits/types/__ia64_fpreg.h:
	New file, contents factored out of ia64/bits/sigcontext.h and
	ia64/bits/ucontext.h.
	* sysdeps/unix/sysv/linux/ia64/Makefile:
	Install bits/types/__ia64_fpreg.h.  Merge subdir=misc blocks.
	* sysdeps/unix/sysv/linux/ia64/bits/sigcontext.h
	* sysdeps/unix/sysv/linux/ia64/bits/ucontext.h:
	Include bits/types/__ia64_fpreg.h for struct ia64_fpreg.

	* sysdeps/unix/sysv/linux/ia64/bits/procfs.h:
	Include bits/types/__ia64_fpreg.h for struct ia64_fpreg.
	Don’t include bits/sigcontext.h or bits/ucontext.h.
	* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h:
	Don’t include bits/sigcontext.h.

	* sysdeps/unix/sysv/linux/riscv/makecontext.c: Include
	ucontext.h, not sys/ucontext.h. Correct function head to match
	prototype in ucontext.h.  Use va_arg to retrieve all arguments
	past argc.

	* sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c:
	Sort list of includes.

	* signal/signal.h, stdlib/ucontext.h
	* sysdeps/unix/sysv/linux/alpha/bits/procfs-prregset.h
	* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h
	* sysdeps/unix/sysv/linux/riscv/bits/procfs.h
	* sysdeps/unix/sysv/linux/s390/bits/procfs.h:
	Include bits/ucontext.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/riscv/sigcontextinfo.h:
	Include signal.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/arm/register-dump.h
	* sysdeps/unix/sysv/linux/csky/register-dump.h:
	Include ucontext.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/aarch64/ucontext_i.sym
	* sysdeps/unix/sysv/linux/alpha/ucontext-offsets.sym
	* sysdeps/unix/sysv/linux/arm/ucontext_i.sym
	* sysdeps/unix/sysv/linux/csky/abiv2/ucontext_i.sym
	* sysdeps/unix/sysv/linux/hppa/ucontext_i.sym
	* sysdeps/unix/sysv/linux/i386/ucontext_i.sym
	* sysdeps/unix/sysv/linux/ia64/sigcontext-offsets.sym
	* sysdeps/unix/sysv/linux/m68k/m680x0/ucontext_i.sym
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.sym
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym
	* sysdeps/unix/sysv/linux/mips/ucontext_i.sym
	* sysdeps/unix/sysv/linux/nios2/ucontext_i.sym
	* sysdeps/unix/sysv/linux/riscv/ucontext_i.sym
	* sysdeps/unix/sysv/linux/s390/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sh/sh3/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sh/sh4/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sparc/sparc32/ucontext_i.sym
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym:
	Include stddef.h and signal.h; don’t include any other headers.

	* scripts/check-obsolete-constructs.py (HEADER_ALLOWED_INCLUDES)
	(SYSDEP_ALLOWED_INCLUDES): Update.

1 files changed, 124 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/mips/bits/ucontext.h b/sysdeps/unix/sysv/linux/mips/bits/ucontext.h
new file mode 100644
index 0000000000..2f4d9d786b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/bits/ucontext.h
@@ -0,0 +1,124 @@
+/* Copyright (C) 1997-2020 Free Software Foundation, Inc.  This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Don't rely on this, the interface is currently messed up and may need to
+   be broken to be fixed.  */
+#ifndef _BITS_UCONTEXT_H
+#define _BITS_UCONTEXT_H	1
+
+#include <features.h>
+
+#include <bits/types/sigset_t.h>
+#include <bits/types/stack_t.h>
+
+#include <sgidefs.h>
+
+
+/* Type for general register.  Even in o32 we assume 64-bit registers,
+   like the kernel.  */
+__extension__ typedef unsigned long long int greg_t;
+
+/* Number of general registers.  */
+#define __NGREG	32
+#define __NFPREG	32
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+# define NFPREG	__NFPREG
+#endif
+
+/* Container for all general registers.  */
+typedef greg_t gregset_t[__NGREG];
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
+/* Container for all FPU registers.  */
+typedef struct {
+	union {
+		double	__ctx(fp_dregs)[__NFPREG];
+		struct {
+			float		_fp_fregs;
+			unsigned int	_fp_pad;
+		} __ctx(fp_fregs)[__NFPREG];
+	} __ctx(fp_r);
+} fpregset_t;
+
+
+/* Context to describe whole processor state.  */
+#if _MIPS_SIM == _ABIO32
+/* Earlier versions of glibc for mips had an entirely different
+   definition of mcontext_t, that didn't even resemble the
+   corresponding kernel data structure.  Fortunately, makecontext,
+   [gs]etcontext et all were not implemented back then, so this can
+   still be rectified.  */
+typedef struct
+  {
+    unsigned int __ctx(regmask);
+    unsigned int __ctx(status);
+    greg_t __ctx(pc);
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
+    unsigned int __ctx(fp_owned);
+    unsigned int __ctx(fpc_csr);
+    unsigned int __ctx(fpc_eir);
+    unsigned int __ctx(used_math);
+    unsigned int __ctx(dsp);
+    greg_t __ctx(mdhi);
+    greg_t __ctx(mdlo);
+    unsigned long __ctx(hi1);
+    unsigned long __ctx(lo1);
+    unsigned long __ctx(hi2);
+    unsigned long __ctx(lo2);
+    unsigned long __ctx(hi3);
+    unsigned long __ctx(lo3);
+  } mcontext_t;
+#else
+typedef struct
+  {
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
+    greg_t __ctx(mdhi);
+    greg_t __ctx(hi1);
+    greg_t __ctx(hi2);
+    greg_t __ctx(hi3);
+    greg_t __ctx(mdlo);
+    greg_t __ctx(lo1);
+    greg_t __ctx(lo2);
+    greg_t __ctx(lo3);
+    greg_t __ctx(pc);
+    unsigned int __ctx(fpc_csr);
+    unsigned int __ctx(used_math);
+    unsigned int __ctx(dsp);
+    unsigned int __glibc_reserved1;
+  } mcontext_t;
+#endif
+
+/* Userlevel context.  */
+typedef struct ucontext_t
+  {
+    unsigned long int __ctx(uc_flags);
+    struct ucontext_t *uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    sigset_t uc_sigmask;
+  } ucontext_t;
+
+#undef __ctx
+
+#endif /* bits/ucontext.h */