commit 240a02bd2bb367d18a4c1672adda5f8c847a9a4d
Author: Florian Weimer <fweimer@redhat.com>
Date:   Sun Jul 9 12:25:35 2017 +0200

    Revert "Fix struct sigaltstack namespace (bug 21517)."
    
    This reverts commit 7553131847151d04d58a02300673f13d73861cbb.

diff --git a/bits/types/stack_t.h b/bits/types/stack_t.h
index 47149fc..3cf0a40 100644
--- a/bits/types/stack_t.h
+++ b/bits/types/stack_t.h
@@ -23,7 +23,7 @@
 #include <stddef.h>
 
 /* Structure describing a signal stack.  */
-typedef struct
+typedef struct sigaltstack
   {
     void *ss_sp;
     size_t ss_size;
diff --git a/debug/segfault.c b/debug/segfault.c
index 78c1cf5..dac9efb 100644
--- a/debug/segfault.c
+++ b/debug/segfault.c
@@ -156,7 +156,7 @@ install_handler (void)
   if (getenv ("SEGFAULT_USE_ALTSTACK") != 0)
     {
       void *stack_mem = malloc (2 * SIGSTKSZ);
-      stack_t ss;
+      struct sigaltstack ss;
 
       if (stack_mem != NULL)
 	{
diff --git a/hurd/hurd/signal.h b/hurd/hurd/signal.h
index e03d53e..f899e81 100644
--- a/hurd/hurd/signal.h
+++ b/hurd/hurd/signal.h
@@ -70,7 +70,7 @@ struct hurd_sigstate
     sigset_t blocked;		/* What signals are blocked.  */
     sigset_t pending;		/* Pending signals, possibly blocked.  */
     struct sigaction actions[NSIG];
-    stack_t sigaltstack;
+    struct sigaltstack sigaltstack;
 
     /* Chain of thread-local signal preemptors; see <hurd/sigpreempt.h>.
        Each element of this chain is in local stack storage, and the chain
diff --git a/hurd/trampoline.c b/hurd/trampoline.c
index e506fd8..8216e22 100644
--- a/hurd/trampoline.c
+++ b/hurd/trampoline.c
@@ -28,7 +28,7 @@
 struct sigcontext *
 _hurd_setup_sighandler (int flags,
 			__sighandler_t handler,
-			stack_t *sigaltstack,
+			struct sigaltstack *sigaltstack,
 			int signo, int sigcode,
 			void *state)
 {
diff --git a/include/signal.h b/include/signal.h
index bcf1455..e39ddc6 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -41,8 +41,8 @@ extern int __sigqueue (__pid_t __pid, int __sig,
 #ifdef __USE_MISC
 extern int __sigreturn (struct sigcontext *__scp);
 #endif
-extern int __sigaltstack (const stack_t *__ss,
-			  stack_t *__oss);
+extern int __sigaltstack (const struct sigaltstack *__ss,
+			  struct sigaltstack *__oss);
 extern int __libc_sigaction (int sig, const struct sigaction *act,
 			     struct sigaction *oact);
 libc_hidden_proto (__libc_sigaction)
diff --git a/signal/sigaltstack.c b/signal/sigaltstack.c
index b70afa7..e4d2319 100644
--- a/signal/sigaltstack.c
+++ b/signal/sigaltstack.c
@@ -21,7 +21,7 @@
 /* Run signals handlers on the stack specified by SS (if not NULL).
    If OSS is not NULL, it is filled in with the old signal stack status.  */
 int
-sigaltstack (const stack_t *ss, stack_t *oss)
+sigaltstack (const struct sigaltstack *ss, struct sigaltstack *oss)
 {
   __set_errno (ENOSYS);
   return -1;
diff --git a/sysdeps/mach/hurd/i386/signal-defines.sym b/sysdeps/mach/hurd/i386/signal-defines.sym
index e42bbbe..9521bd7 100644
--- a/sysdeps/mach/hurd/i386/signal-defines.sym
+++ b/sysdeps/mach/hurd/i386/signal-defines.sym
@@ -5,6 +5,6 @@
 
 HURD_SIGSTATE__SIGALTSTACK__OFFSET	offsetof(struct hurd_sigstate, sigaltstack)
 
-SIGALTSTACK__SS_SP__OFFSET		offsetof(stack_t, ss_sp)
-SIGALTSTACK__SS_SIZE__OFFSET		offsetof(stack_t, ss_size)
-SIGALTSTACK__SS_FLAGS__OFFSET		offsetof(stack_t, ss_flags)
+SIGALTSTACK__SS_SP__OFFSET		offsetof(struct sigaltstack, ss_sp)
+SIGALTSTACK__SS_SIZE__OFFSET		offsetof(struct sigaltstack, ss_size)
+SIGALTSTACK__SS_FLAGS__OFFSET		offsetof(struct sigaltstack, ss_flags)
diff --git a/sysdeps/mach/hurd/sigaltstack.c b/sysdeps/mach/hurd/sigaltstack.c
index 4fba69e..06a6a5c 100644
--- a/sysdeps/mach/hurd/sigaltstack.c
+++ b/sysdeps/mach/hurd/sigaltstack.c
@@ -22,16 +22,16 @@
 /* Run signals handlers on the stack specified by SS (if not NULL).
    If OSS is not NULL, it is filled in with the old signal stack status.  */
 int
-__sigaltstack (const stack_t *argss, stack_t *oss)
+__sigaltstack (const struct sigaltstack *argss, struct sigaltstack *oss)
 {
   struct hurd_sigstate *s;
-  stack_t ss, old;
+  struct sigaltstack ss, old;
 
   /* Fault before taking any locks.  */
   if (argss != NULL)
     ss = *argss;
   if (oss != NULL)
-    *(volatile stack_t *) oss = *oss;
+    *(volatile struct sigaltstack *) oss = *oss;
 
   s = _hurd_self_sigstate ();
   __spin_lock (&s->lock);
diff --git a/sysdeps/mach/hurd/sigstack.c b/sysdeps/mach/hurd/sigstack.c
index 484efb6..a3a11f9 100644
--- a/sysdeps/mach/hurd/sigstack.c
+++ b/sysdeps/mach/hurd/sigstack.c
@@ -24,7 +24,7 @@
 int
 sigstack (struct sigstack *ss, struct sigstack *oss)
 {
-  stack_t as, oas;
+  struct sigaltstack as, oas;
 
   as.ss_sp = ss->ss_sp;
   as.ss_size = 0;
diff --git a/sysdeps/unix/sysv/linux/alpha/sys/procfs.h b/sysdeps/unix/sysv/linux/alpha/sys/procfs.h
index abc9fd8..2cd69d4 100644
--- a/sysdeps/unix/sysv/linux/alpha/sys/procfs.h
+++ b/sysdeps/unix/sysv/linux/alpha/sys/procfs.h
@@ -71,7 +71,7 @@ struct elf_prstatus
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
 #if 0
-    stack_t pr_altstack;		/* Alternate stack info.  */
+    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
     struct sigaction pr_action;		/* Signal action for current sig.  */
 #endif
     __pid_t pr_pid;
diff --git a/sysdeps/unix/sysv/linux/bits/types/stack_t.h b/sysdeps/unix/sysv/linux/bits/types/stack_t.h
index 373c227..497e42b 100644
--- a/sysdeps/unix/sysv/linux/bits/types/stack_t.h
+++ b/sysdeps/unix/sysv/linux/bits/types/stack_t.h
@@ -23,7 +23,7 @@
 #include <stddef.h>
 
 /* Structure describing a signal stack.  */
-typedef struct
+typedef struct sigaltstack
   {
     void *ss_sp;
     int ss_flags;
diff --git a/sysdeps/unix/sysv/linux/hppa/____longjmp_chk.c b/sysdeps/unix/sysv/linux/hppa/____longjmp_chk.c
index 48aaeb3..3a04250 100644
--- a/sysdeps/unix/sysv/linux/hppa/____longjmp_chk.c
+++ b/sysdeps/unix/sysv/linux/hppa/____longjmp_chk.c
@@ -27,7 +27,7 @@
        destroyed must all have stack values higher than ours.  */	\
     if ((unsigned long) (sp) > this_sp)					\
       {									\
-        stack_t oss;							\
+        struct sigaltstack oss;						\
         INTERNAL_SYSCALL_DECL (err);					\
         int result = INTERNAL_SYSCALL (sigaltstack, err, 2, NULL, &oss);\
 	/* If we aren't using an alternate stack then we have already	\
diff --git a/sysdeps/unix/sysv/linux/ia64/sys/procfs.h b/sysdeps/unix/sysv/linux/ia64/sys/procfs.h
index afe54fb..93e569b 100644
--- a/sysdeps/unix/sysv/linux/ia64/sys/procfs.h
+++ b/sysdeps/unix/sysv/linux/ia64/sys/procfs.h
@@ -73,7 +73,7 @@ struct elf_prstatus
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
 #if 0
-    stack_t pr_altstack;		/* Alternate stack info.  */
+    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
     struct sigaction pr_action;		/* Signal action for current sig.  */
 #endif
     __pid_t pr_pid;
diff --git a/sysdeps/unix/sysv/linux/m68k/____longjmp_chk.c b/sysdeps/unix/sysv/linux/m68k/____longjmp_chk.c
index 030e463..3539b54 100644
--- a/sysdeps/unix/sysv/linux/m68k/____longjmp_chk.c
+++ b/sysdeps/unix/sysv/linux/m68k/____longjmp_chk.c
@@ -24,7 +24,7 @@
     register unsigned long this_sp asm ("sp");				      \
     if ((unsigned long) (sp) < this_sp)					      \
       {									      \
-	stack_t oss;							      \
+	struct sigaltstack oss;						      \
 	INTERNAL_SYSCALL_DECL (err);					      \
 	int result = INTERNAL_SYSCALL (sigaltstack, err, 2, NULL, &oss);      \
 	if (!INTERNAL_SYSCALL_ERROR_P (result, err)			      \
diff --git a/sysdeps/unix/sysv/linux/mips/bits/types/stack_t.h b/sysdeps/unix/sysv/linux/mips/bits/types/stack_t.h
index b9635ad..ef06072 100644
--- a/sysdeps/unix/sysv/linux/mips/bits/types/stack_t.h
+++ b/sysdeps/unix/sysv/linux/mips/bits/types/stack_t.h
@@ -23,7 +23,7 @@
 #include <stddef.h>
 
 /* Structure describing a signal stack.  */
-typedef struct
+typedef struct sigaltstack
   {
     void *ss_sp;
     size_t ss_size;
diff --git a/sysdeps/unix/sysv/linux/powerpc/sys/procfs.h b/sysdeps/unix/sysv/linux/powerpc/sys/procfs.h
index 61ded22..b7b7b0b 100644
--- a/sysdeps/unix/sysv/linux/powerpc/sys/procfs.h
+++ b/sysdeps/unix/sysv/linux/powerpc/sys/procfs.h
@@ -83,7 +83,7 @@ struct elf_prstatus
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
 #if 0
-    stack_t pr_altstack;		/* Alternate stack info.  */
+    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
     struct sigaction pr_action;		/* Signal action for current sig.  */
 #endif
     __pid_t pr_pid;
diff --git a/sysdeps/unix/sysv/linux/sh/sys/procfs.h b/sysdeps/unix/sysv/linux/sh/sys/procfs.h
index 414911a..c41c877 100644
--- a/sysdeps/unix/sysv/linux/sh/sys/procfs.h
+++ b/sysdeps/unix/sysv/linux/sh/sys/procfs.h
@@ -55,7 +55,7 @@ struct elf_prstatus
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
 #if 0
-    stack_t pr_altstack;		/* Alternate stack info.  */
+    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
     struct sigaction pr_action;		/* Signal action for current sig.  */
 #endif
     __pid_t pr_pid;
diff --git a/sysdeps/unix/sysv/linux/sys/procfs.h b/sysdeps/unix/sysv/linux/sys/procfs.h
index b3b2cf3..8dfa0c0 100644
--- a/sysdeps/unix/sysv/linux/sys/procfs.h
+++ b/sysdeps/unix/sysv/linux/sys/procfs.h
@@ -58,7 +58,7 @@ struct elf_prstatus
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
 #if 0
-    stack_t pr_altstack;		/* Alternate stack info.  */
+    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
     struct sigaction pr_action;		/* Signal action for current sig.  */
 #endif
     __pid_t pr_pid;