Patchwork Rename struct ucontext tag (bug 21457)

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Submitter Joseph Myers
Date June 12, 2017, 11:58 p.m.
Message ID <alpine.DEB.2.20.1706122358120.17570@digraph.polyomino.org.uk>
Download mbox | patch
Permalink /patch/20976/
State New
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Comments

Joseph Myers - June 12, 2017, 11:58 p.m.
The ucontext_t type has a tag struct ucontext.  As with previous such
issues for siginfo_t and stack_t, this tag is not permitted by POSIX
(is not in a reserved namespace), and so namespace conformance means
breaking C++ name mangling for this type.

In this case, the type does need to have some tag rather than just a
typedef name, because it includes a pointer to itself.  This patch
uses struct ucontext_t as the new tag, so the type is mangled as
ucontext_t (the POSIX *_t reservation applies in all namespaces, not
just the namespace of ordinary identifiers).  Another reserved name
such as struct __ucontext could of course be used.

Because of other namespace issues, this patch does not by itself fix
bug 21457 or allow any XFAILs to be removed.

Tested for x86_64, and with build-many-glibcs.py.

2017-06-12  Joseph Myers  <joseph@codesourcery.com>

	[BZ #21457]
	* sysdeps/arm/sys/ucontext.h (struct ucontext): Rename to struct
	ucontext_t.
	* sysdeps/generic/sys/ucontext.h (struct ucontext): Likewise.
	* sysdeps/i386/sys/ucontext.h (struct ucontext): Likewise.
	* sysdeps/m68k/sys/ucontext.h (struct ucontext): Likewise.
	* sysdeps/mips/sys/ucontext.h (struct ucontext): Likewise.
	* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h (struct
	ucontext): Likewise.
	* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/arm/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/hppa/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/ia64/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h (struct
	ucontext): Likewise.
	* sysdeps/unix/sysv/linux/s390/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/tile/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/unix/sysv/linux/x86/sys/ucontext.h (struct ucontext):
	Likewise.
	* sysdeps/microblaze/backtrace_linux.c (_identify_sighandler): Use
	ucontext_t instead of struct ucontext.
	* sysdeps/powerpc/powerpc32/backtrace.c (struct
	rt_signal_frame_32): Likewise.
	* sysdeps/powerpc/powerpc64/backtrace.c (struct signal_frame_64):
	Likewise.
	* sysdeps/unix/sysv/linux/aarch64/kernel_rt_sigframe.h (struct
	kernel_rt_sigframe): Likewise.
	* sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h (SIGCONTEXT):
	Likewise.
	* sysdeps/unix/sysv/linux/arm/register-dump.h (register_dump):
	Likewise.
	* sysdeps/unix/sysv/linux/arm/sigcontextinfo.h (SIGCONTEXT):
	Likewise.
	* sysdeps/unix/sysv/linux/hppa/profil-counter.h
	(__profil_counter): Likewise.
	* sysdeps/unix/sysv/linux/microblaze/sigcontextinfo.h
	(SIGCONTEXT): Likewise.
	* sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h (struct
	kernel_rt_sigframe): Likewise.
	* sysdeps/unix/sysv/linux/nios2/kernel_rt_sigframe.h (struct
	kernel_rt_sigframe): Likewise.
	* sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h (SIGCONTEXT):
	Likewise.
	* sysdeps/unix/sysv/linux/sh/makecontext.S (__makecontext):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/makecontext.c
	(__start_context): Likewise.
	* sysdeps/unix/sysv/linux/tile/sigcontextinfo.h (SIGCONTEXT):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/register-dump.h (register_dump):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sigcontextinfo.h (SIGCONTEXT):
	Likewise.
Florian Weimer - June 13, 2017, 6:49 a.m.
On 06/13/2017 01:58 AM, Joseph Myers wrote:
> The ucontext_t type has a tag struct ucontext.  As with previous such
> issues for siginfo_t and stack_t, this tag is not permitted by POSIX
> (is not in a reserved namespace), and so namespace conformance means
> breaking C++ name mangling for this type.

I don't see a reference in Fedora to a _Z*ucontext* symbol, so I don't
expect any ABI problems.

> In this case, the type does need to have some tag rather than just a
> typedef name, because it includes a pointer to itself.  This patch
> uses struct ucontext_t as the new tag, so the type is mangled as
> ucontext_t (the POSIX *_t reservation applies in all namespaces, not
> just the namespace of ordinary identifiers).  Another reserved name
> such as struct __ucontext could of course be used.

How widely known is the reserved nature of _t names?  Maybe the __
prefix would communicate better that this is an internal name?  Although
I assume we will never change it again, so applications referencing the
new name should not face any future problems.

Thanks,
Florian
Joseph Myers - June 15, 2017, 10:02 p.m.
On Tue, 13 Jun 2017, Florian Weimer wrote:

> > In this case, the type does need to have some tag rather than just a
> > typedef name, because it includes a pointer to itself.  This patch
> > uses struct ucontext_t as the new tag, so the type is mangled as
> > ucontext_t (the POSIX *_t reservation applies in all namespaces, not
> > just the namespace of ordinary identifiers).  Another reserved name
> > such as struct __ucontext could of course be used.
> 
> How widely known is the reserved nature of _t names?  Maybe the __
> prefix would communicate better that this is an internal name?  Although
> I assume we will never change it again, so applications referencing the
> new name should not face any future problems.

Since this is a (C++) ABI, we don't want to change it unnecessarily, so I 
don't see a reason for subsequent changes.  We just need to pick the name 
we want to use (and then people with patches such as the RISC-V port that 
add sys/ucontext.h files will need to follow accordingly).
Joseph Myers - June 16, 2017, 9:36 p.m.
Consider the sysdeps/microblaze/backtrace_linux.c changes removed from 
this patch.  That file is deliberately using the kernel struct ucontext, 
not the userspace one.
Joseph Myers - June 19, 2017, 11:11 a.m.
Ping.  This patch 
<https://sourceware.org/ml/libc-alpha/2017-06/msg00498.html> (adjusted as 
noted at <https://sourceware.org/ml/libc-alpha/2017-06/msg00752.html>) is 
pending review.
Joseph Myers - June 26, 2017, 11:11 a.m.
Ping^2.  This patch 
<https://sourceware.org/ml/libc-alpha/2017-06/msg00498.html> (adjusted as 
noted at <https://sourceware.org/ml/libc-alpha/2017-06/msg00752.html>) is 
still pending review.
Zack Weinberg - June 26, 2017, 9:11 p.m.
On 06/12/2017 07:58 PM, Joseph Myers wrote:
> The ucontext_t type has a tag struct ucontext.  As with previous such
> issues for siginfo_t and stack_t, this tag is not permitted by POSIX
> (is not in a reserved namespace), and so namespace conformance means
> breaking C++ name mangling for this type.
> 
> In this case, the type does need to have some tag rather than just a
> typedef name, because it includes a pointer to itself.  This patch
> uses struct ucontext_t as the new tag, so the type is mangled as
> ucontext_t (the POSIX *_t reservation applies in all namespaces, not
> just the namespace of ordinary identifiers).  Another reserved name
> such as struct __ucontext could of course be used.

This looks OK to me.

On the entirely arbitrary basis that the name mangling for

    typedef struct ucontext_t { ... } ucontext_t;

is the same as the name mangling for

    typedef struct { ... } ucontext_t;

whereas

    typedef struct __ucontext { ... } ucontext_t;

would put the string '__ucontext' into the mangled names, I vote for the
'ucontext_t' struct tag.

zw

Patch

diff --git a/NEWS b/NEWS
index 991ee63..89cdbf6 100644
--- a/NEWS
+++ b/NEWS
@@ -80,6 +80,9 @@  Version 2.26
 * The stack_t type no longer has the name struct sigaltstack.  This changes
   the C++ name mangling for interfaces involving this type.
 
+* The ucontext_t type no longer has the name struct ucontext.  This changes
+  the C++ name mangling for interfaces involving this type.
+
 * The synchronization that pthread_spin_unlock performs has been changed
   to now be equivalent to a C11 atomic store with release memory order to
   the spin lock's memory location.  This ensures correct synchronization
diff --git a/sysdeps/arm/sys/ucontext.h b/sysdeps/arm/sys/ucontext.h
index 722300a..464a353 100644
--- a/sysdeps/arm/sys/ucontext.h
+++ b/sysdeps/arm/sys/ucontext.h
@@ -98,10 +98,10 @@  typedef struct
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     sigset_t uc_sigmask;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
diff --git a/sysdeps/generic/sys/ucontext.h b/sysdeps/generic/sys/ucontext.h
index a64460c..e4679d3 100644
--- a/sysdeps/generic/sys/ucontext.h
+++ b/sysdeps/generic/sys/ucontext.h
@@ -32,10 +32,10 @@ 
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/i386/sys/ucontext.h b/sysdeps/i386/sys/ucontext.h
index fb5df11..be8c7e5 100644
--- a/sysdeps/i386/sys/ucontext.h
+++ b/sysdeps/i386/sys/ucontext.h
@@ -126,10 +126,10 @@  typedef struct
 #undef __ctxt
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     sigset_t uc_sigmask;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
diff --git a/sysdeps/m68k/sys/ucontext.h b/sysdeps/m68k/sys/ucontext.h
index a742aaf..00c4af4 100644
--- a/sysdeps/m68k/sys/ucontext.h
+++ b/sysdeps/m68k/sys/ucontext.h
@@ -113,10 +113,10 @@  typedef struct
 #endif
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
 {
   unsigned long int uc_flags;
-  struct ucontext *uc_link;
+  struct ucontext_t *uc_link;
   sigset_t uc_sigmask;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
diff --git a/sysdeps/microblaze/backtrace_linux.c b/sysdeps/microblaze/backtrace_linux.c
index 2fe3c5c..b551963 100644
--- a/sysdeps/microblaze/backtrace_linux.c
+++ b/sysdeps/microblaze/backtrace_linux.c
@@ -28,7 +28,7 @@  _identify_sighandler (unsigned long fp, unsigned long pc,
                       unsigned long *retaddr)
 {
   unsigned long *tramp = 0;
-  struct ucontext *uc;
+  ucontext_t *uc;
 
   if (*retaddr == 0)
     {
@@ -43,8 +43,8 @@  _identify_sighandler (unsigned long fp, unsigned long pc,
              int sig_num, siginfo_t * info, void * ucontext
              therefore ucontext is the 3rd argument.  */
           unsigned long ucptr = ((unsigned long) tramp
-                                 - sizeof (struct ucontext));
-          uc = (struct ucontext *) ucptr;
+                                 - sizeof (ucontext_t));
+          uc = (ucontext_t *) ucptr;
           *pprev_pc = uc->uc_mcontext.regs.pc;
           /* Need to record the return address since the return address of the
              function which causes this signal may not be recorded in the
diff --git a/sysdeps/mips/sys/ucontext.h b/sysdeps/mips/sys/ucontext.h
index 4bc1bc1..d69656b 100644
--- a/sysdeps/mips/sys/ucontext.h
+++ b/sysdeps/mips/sys/ucontext.h
@@ -159,14 +159,14 @@  typedef struct
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
 {
 #if _MIPS_SIM == _ABIO32
   unsigned long int uc_flags;
 #else
   __uint64_t uc_flags;
 #endif
-  struct ucontext *uc_link;
+  struct ucontext_t *uc_link;
   sigset_t uc_sigmask;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
diff --git a/sysdeps/powerpc/powerpc32/backtrace.c b/sysdeps/powerpc/powerpc32/backtrace.c
index 3940621..187c3b3 100644
--- a/sysdeps/powerpc/powerpc32/backtrace.c
+++ b/sysdeps/powerpc/powerpc32/backtrace.c
@@ -64,7 +64,7 @@  is_sigtramp_address (void *nip)
 struct rt_signal_frame_32 {
   char               dummy[SIGNAL_FRAMESIZE + 16];
   siginfo_t          info;
-  struct ucontext    uc;
+  ucontext_t         uc;
   /* We don't care about the rest, since IP value is at 'uc' field.  */
 };
 
diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c
index 723948d..919bf1c 100644
--- a/sysdeps/powerpc/powerpc64/backtrace.c
+++ b/sysdeps/powerpc/powerpc64/backtrace.c
@@ -50,7 +50,7 @@  struct layout
 struct signal_frame_64 {
 #define SIGNAL_FRAMESIZE 128
   char dummy[SIGNAL_FRAMESIZE];
-  struct ucontext uc;
+  ucontext_t uc;
   /* We don't care about the rest, since the IP value is at 'uc' field.  */
 };
 
diff --git a/sysdeps/unix/sysv/linux/aarch64/kernel_rt_sigframe.h b/sysdeps/unix/sysv/linux/aarch64/kernel_rt_sigframe.h
index e67ddfa..cb65bd4 100644
--- a/sysdeps/unix/sysv/linux/aarch64/kernel_rt_sigframe.h
+++ b/sysdeps/unix/sysv/linux/aarch64/kernel_rt_sigframe.h
@@ -21,5 +21,5 @@ 
 struct kernel_rt_sigframe
 {
   siginfo_t info;
-  struct ucontext uc;
+  ucontext_t uc;
 };
diff --git a/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h b/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
index b28ad5b..7793d11 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
@@ -19,7 +19,7 @@ 
 #include <stdint.h>
 #include <sys/ucontext.h>
 
-#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT siginfo_t *_si, ucontext_t *
 #define GET_PC(ctx) ((void *) (uintptr_t) (ctx)->uc_mcontext.pc)
 
 /* There is no reliable way to get the sigcontext unless we use a
diff --git a/sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h b/sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h
index 16c7acf..4f602fc 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h
@@ -47,10 +47,10 @@  typedef elf_fpregset_t	fpregset_t;
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     sigset_t uc_sigmask;
     mcontext_t uc_mcontext;
diff --git a/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h b/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
index b9e5903..bf95205 100644
--- a/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
@@ -54,10 +54,10 @@  typedef fpreg_t fpregset_t[__NFPREG];
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     unsigned long __uc_osf_sigmask;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
diff --git a/sysdeps/unix/sysv/linux/arm/register-dump.h b/sysdeps/unix/sysv/linux/arm/register-dump.h
index 0f2bed7..d31b324 100644
--- a/sysdeps/unix/sysv/linux/arm/register-dump.h
+++ b/sysdeps/unix/sysv/linux/arm/register-dump.h
@@ -44,7 +44,7 @@  hexvalue (unsigned long int value, char *buf, size_t len)
 }
 
 static void
-register_dump (int fd, const struct ucontext *ctx)
+register_dump (int fd, const ucontext_t *ctx)
 {
   char regs[21][8];
   struct iovec iov[97];
diff --git a/sysdeps/unix/sysv/linux/arm/sigcontextinfo.h b/sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
index f2a66d1..d3313af 100644
--- a/sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
@@ -18,7 +18,7 @@ 
 
 #include <sys/ucontext.h>
 
-#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT siginfo_t *_si, ucontext_t *
 #define SIGCONTEXT_EXTRA_ARGS _si,
 
 /* The sigcontext structure changed between 2.0 and 2.1 kernels.  On any
diff --git a/sysdeps/unix/sysv/linux/arm/sys/ucontext.h b/sysdeps/unix/sysv/linux/arm/sys/ucontext.h
index 0ce9b14..1083d66 100644
--- a/sysdeps/unix/sysv/linux/arm/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/arm/sys/ucontext.h
@@ -101,10 +101,10 @@  typedef struct _libc_fpstate fpregset_t;
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/hppa/profil-counter.h b/sysdeps/unix/sysv/linux/hppa/profil-counter.h
index 0bb6e37..69cf830 100644
--- a/sysdeps/unix/sysv/linux/hppa/profil-counter.h
+++ b/sysdeps/unix/sysv/linux/hppa/profil-counter.h
@@ -17,7 +17,7 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 static void
-__profil_counter (int signr, siginfo_t *si, struct ucontext *uctx)
+__profil_counter (int signr, siginfo_t *si, ucontext_t *uctx)
 {
   unsigned long ip = uctx->uc_mcontext.sc_iaoq[0] & ~0x3;
   profil_count ((void *) ip);
diff --git a/sysdeps/unix/sysv/linux/hppa/sys/ucontext.h b/sysdeps/unix/sysv/linux/hppa/sys/ucontext.h
index 982b4c4..2fd7e91 100644
--- a/sysdeps/unix/sysv/linux/hppa/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/hppa/sys/ucontext.h
@@ -55,10 +55,10 @@  typedef struct fpregset
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/ia64/sys/ucontext.h b/sysdeps/unix/sysv/linux/ia64/sys/ucontext.h
index 5ed6929..9cd686c 100644
--- a/sysdeps/unix/sysv/linux/ia64/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/ia64/sys/ucontext.h
@@ -43,7 +43,7 @@  typedef struct sigcontext mcontext_t;
 # define _SC_GR0_OFFSET	0xc8	/* pray that this is correct... */
 #endif
 
-typedef struct ucontext
+typedef struct ucontext_t
   {
     union
       {
@@ -51,7 +51,7 @@  typedef struct ucontext
 	struct
 	  {
 	    unsigned long _pad[_SC_GR0_OFFSET/8];
-	    struct ucontext *_link;	/* this should overlay sc_gr[0] */
+	    struct ucontext_t *_link;	/* this should overlay sc_gr[0] */
 	  }
 	_uc;
       }
diff --git a/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h b/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
index e6ecbe6..280ec37 100644
--- a/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
@@ -118,10 +118,10 @@  typedef struct
 #endif
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
 {
   unsigned long uc_flags;
-  struct ucontext *uc_link;
+  struct ucontext_t *uc_link;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
   unsigned long uc_filler[80];
diff --git a/sysdeps/unix/sysv/linux/microblaze/sigcontextinfo.h b/sysdeps/unix/sysv/linux/microblaze/sigcontextinfo.h
index 071ca94..145b3cb 100644
--- a/sysdeps/unix/sysv/linux/microblaze/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/microblaze/sigcontextinfo.h
@@ -16,7 +16,7 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#define SIGCONTEXT int _code, struct ucontext *
+#define SIGCONTEXT int _code, ucontext_t *
 #define SIGCONTEXT_EXTRA_ARGS _code,
 #define GET_PC(ctx)    ((void *) (ctx)->uc_mcontext.regs.pc)
 #define GET_FRAME(ctx) ((void *) (ctx)->uc_mcontext.regs.sp)
diff --git a/sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h b/sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h
index e870b20..8f62b57 100644
--- a/sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h
+++ b/sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h
@@ -6,7 +6,7 @@  typedef struct kernel_rt_sigframe
     uint32_t rs_ass[4];
     uint32_t rs_code[2];
     siginfo_t rs_info;
-    struct ucontext rs_uc;
+    ucontext_t rs_uc;
     uint32_t rs_altcode[8] __attribute__ ((__aligned__ (1 << 7)));
   }
 kernel_rt_sigframe_t;
diff --git a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h b/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
index 048e9a4..19c0ed9 100644
--- a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
@@ -113,10 +113,10 @@  typedef struct
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/nios2/kernel_rt_sigframe.h b/sysdeps/unix/sysv/linux/nios2/kernel_rt_sigframe.h
index f840eff..3dc59d8 100644
--- a/sysdeps/unix/sysv/linux/nios2/kernel_rt_sigframe.h
+++ b/sysdeps/unix/sysv/linux/nios2/kernel_rt_sigframe.h
@@ -22,5 +22,5 @@ 
 struct kernel_rt_sigframe
 {
   siginfo_t info;
-  struct ucontext uc;
+  ucontext_t uc;
 };
diff --git a/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h b/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
index 51b715c..b244478 100644
--- a/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
@@ -19,7 +19,7 @@ 
 #include <sys/ucontext.h>
 #include "kernel-features.h"
 
-#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT siginfo_t *_si, ucontext_t *
 #define GET_PC(ctx) ((void *) (ctx)->uc_mcontext.regs[27])
 
 /* There is no reliable way to get the sigcontext unless we use a
diff --git a/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h b/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
index af8d75c..4754657 100644
--- a/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
@@ -1,4 +1,4 @@ 
-/* struct ucontext definition, Nios II version.
+/* ucontext_t definition, Nios II version.
    Copyright (C) 2015-2017 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -50,10 +50,10 @@  typedef struct mcontext
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h b/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
index b460f23..2177487 100644
--- a/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
@@ -148,10 +148,10 @@  typedef struct {
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
 #if __WORDSIZE == 32
     /*
diff --git a/sysdeps/unix/sysv/linux/s390/sys/ucontext.h b/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
index 183da5c..d6bf4d8 100644
--- a/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
@@ -83,10 +83,10 @@  typedef struct
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/sh/makecontext.S b/sysdeps/unix/sysv/linux/sh/makecontext.S
index 4506961..b48eb61 100644
--- a/sysdeps/unix/sysv/linux/sh/makecontext.S
+++ b/sysdeps/unix/sysv/linux/sh/makecontext.S
@@ -21,7 +21,7 @@ 
 
 #include "ucontext_i.h"
 
-/* void __makecontext (struct ucontext *ucp, void (*func)(), int argc, ...);
+/* void __makecontext (ucontext_t *ucp, void (*func)(), int argc, ...);
   __makecontext sets up a stack and registers for context to run a given
   function.  The registers are set up like this:
     r4-r7: parameters 1 to 4
diff --git a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
index d44f95e..2f42d3a 100644
--- a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
@@ -115,10 +115,10 @@  typedef struct
 #undef __ctx
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/makecontext.c b/sysdeps/unix/sysv/linux/sparc/sparc64/makecontext.c
index ca174d0..9712740 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/makecontext.c
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/makecontext.c
@@ -21,7 +21,7 @@ 
 #include <stdlib.h>
 #include <ucontext.h>
 
-extern void __start_context (struct ucontext *ucp);
+extern void __start_context (ucontext_t *ucp);
 
 void
 __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
diff --git a/sysdeps/unix/sysv/linux/sparc/sys/ucontext.h b/sysdeps/unix/sysv/linux/sparc/sys/ucontext.h
index 7ce5f2b..dc0d316 100644
--- a/sysdeps/unix/sysv/linux/sparc/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/sparc/sys/ucontext.h
@@ -82,8 +82,8 @@  typedef struct {
 	mc_fpu_t	mc_fpregs;
 } mcontext_t;
 
-typedef struct ucontext {
-	struct ucontext		*uc_link;
+typedef struct ucontext_t {
+	struct ucontext_t	*uc_link;
 	unsigned long		uc_flags;
 	unsigned long		__uc_sigmask;
 	mcontext_t		uc_mcontext;
@@ -261,10 +261,10 @@  typedef struct
 
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long   uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     sigset_t	    uc_sigmask;
     stack_t         uc_stack;
     mcontext_t      uc_mcontext;
diff --git a/sysdeps/unix/sysv/linux/tile/sigcontextinfo.h b/sysdeps/unix/sysv/linux/tile/sigcontextinfo.h
index 8908c58..bad81e4 100644
--- a/sysdeps/unix/sysv/linux/tile/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/tile/sigcontextinfo.h
@@ -18,7 +18,7 @@ 
 
 #include <arch/abi.h>
 
-#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT siginfo_t *_si, ucontext_t *
 #define SIGCONTEXT_EXTRA_ARGS _si,
 #define GET_PC(ctx)	((void *) (long) ctx->uc_mcontext.pc)
 #define GET_FRAME(ctx)	((void *) (long) ctx->uc_mcontext.regs[TREG_FP])
diff --git a/sysdeps/unix/sysv/linux/tile/sys/ucontext.h b/sysdeps/unix/sysv/linux/tile/sys/ucontext.h
index 7e5cf4a..fcbe3ff 100644
--- a/sysdeps/unix/sysv/linux/tile/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/tile/sys/ucontext.h
@@ -60,10 +60,10 @@  enum
 typedef struct sigcontext mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/x86/sys/ucontext.h b/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
index 5fd64bf..a45e16a 100644
--- a/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
@@ -139,10 +139,10 @@  typedef struct
 } mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
@@ -243,10 +243,10 @@  typedef struct
   } mcontext_t;
 
 /* Userlevel context.  */
-typedef struct ucontext
+typedef struct ucontext_t
   {
     unsigned long int uc_flags;
-    struct ucontext *uc_link;
+    struct ucontext_t *uc_link;
     stack_t uc_stack;
     mcontext_t uc_mcontext;
     sigset_t uc_sigmask;
diff --git a/sysdeps/unix/sysv/linux/x86_64/register-dump.h b/sysdeps/unix/sysv/linux/x86_64/register-dump.h
index 6a52957..dda8ea3 100644
--- a/sysdeps/unix/sysv/linux/x86_64/register-dump.h
+++ b/sysdeps/unix/sysv/linux/x86_64/register-dump.h
@@ -64,7 +64,7 @@  hexvalue (unsigned long int value, char *buf, size_t len)
 }
 
 static void
-register_dump (int fd, struct ucontext *ctx)
+register_dump (int fd, ucontext_t *ctx)
 {
   char regs[25][16];
   char fpregs[30][8];
diff --git a/sysdeps/unix/sysv/linux/x86_64/sigcontextinfo.h b/sysdeps/unix/sysv/linux/x86_64/sigcontextinfo.h
index e935353..131f96b 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/x86_64/sigcontextinfo.h
@@ -17,7 +17,7 @@ 
 
 #include <stdint.h>
 
-#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT siginfo_t *_si, ucontext_t *
 #define SIGCONTEXT_EXTRA_ARGS _si,
 #define GET_PC(ctx)	\
   ((void *) (uintptr_t) (ctx)->uc_mcontext.gregs[REG_RIP])