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, 138 insertions, 0 deletions

diff --git a/sysdeps/i386/bits/ucontext.h b/sysdeps/i386/bits/ucontext.h
new file mode 100644
index 0000000..7218781
--- /dev/null
+++ b/sysdeps/i386/bits/ucontext.h
@@ -0,0 +1,138 @@
+/* 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/>.  */
+
+/* System V/i386 ABI compliant context switching support.  */
+
+#ifndef _BITS_UCONTEXT_H
+#define _BITS_UCONTEXT_H	1
+
+#include <features.h>
+
+#include <bits/types/sigset_t.h>
+#include <bits/types/stack_t.h>
+
+
+/* Type for general register.  */
+typedef int greg_t;
+
+/* Number of general registers.  */
+#define __NGREG	19
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
+
+/* Container for all general registers.  */
+typedef greg_t gregset_t[__NGREG];
+
+#ifdef __USE_MISC
+/* Number of each register is the `gregset_t' array.  */
+enum
+{
+  REG_GS = 0,
+# define REG_GS	REG_GS
+  REG_FS,
+# define REG_FS	REG_FS
+  REG_ES,
+# define REG_ES	REG_ES
+  REG_DS,
+# define REG_DS	REG_DS
+  REG_EDI,
+# define REG_EDI	REG_EDI
+  REG_ESI,
+# define REG_ESI	REG_ESI
+  REG_EBP,
+# define REG_EBP	REG_EBP
+  REG_ESP,
+# define REG_ESP	REG_ESP
+  REG_EBX,
+# define REG_EBX	REG_EBX
+  REG_EDX,
+# define REG_EDX	REG_EDX
+  REG_ECX,
+# define REG_ECX	REG_ECX
+  REG_EAX,
+# define REG_EAX	REG_EAX
+  REG_TRAPNO,
+# define REG_TRAPNO	REG_TRAPNO
+  REG_ERR,
+# define REG_ERR	REG_ERR
+  REG_EIP,
+# define REG_EIP	REG_EIP
+  REG_CS,
+# define REG_CS	REG_CS
+  REG_EFL,
+# define REG_EFL	REG_EFL
+  REG_UESP,
+# define REG_UESP	REG_UESP
+  REG_SS
+# define REG_SS	REG_SS
+};
+#endif
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+# define __ctxt(tag) tag
+#else
+# define __ctx(fld) __ ## fld
+# define __ctxt(tag) /* Empty.  */
+#endif
+
+/* Structure to describe FPU registers.  */
+typedef struct
+  {
+    union
+      {
+	struct __ctxt(fpchip_state)
+	  {
+	    int __ctx(state)[27];
+	    int __ctx(status);
+	  } __ctx(fpchip_state);
+
+	struct __ctxt(fp_emul_space)
+	  {
+	    char __ctx(fp_emul)[246];
+	    char __ctx(fp_epad)[2];
+	  } __ctx(fp_emul_space);
+
+	int __ctx(f_fpregs)[62];
+      } __ctx(fp_reg_set);
+
+    long int __ctx(f_wregs)[33];
+  } fpregset_t;
+
+/* Context to describe whole processor state.  */
+typedef struct
+  {
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
+  } mcontext_t;
+
+/* Userlevel context.  */
+typedef struct ucontext_t
+  {
+    unsigned long int __ctx(uc_flags);
+    struct ucontext_t *uc_link;
+    sigset_t uc_sigmask;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    long int __glibc_reserved1[5];
+  } ucontext_t;
+
+#undef __ctx
+#undef __ctxt
+
+#endif /* bits/ucontext.h */