[2/2] Refactor internal-signals.h

  The main drive is to optimize the internal usage and required size
when sigset_t in embedded in other data structures.  On Linux, the
current supported signal set requires up to 8 bytes (16 on mips),
wat lower than the user defined sigset_t (128 bytes).

A new internal type internal_sigset_t is added, along with the
functions to operate on it similar to the ones for sigset_t.  The
internal-signals.h is also refactores to remove unused functions

Besides small stack usage on some functions (posix_spawn, abort)
it lower the struct pthread by about 120 bytes (112 on mips).

Checked on x86_64-linux-gnu.
---
 nptl/descr.h                                  |   3 +-
 nptl/pthread_attr_setsigmask.c                |   2 +-
 nptl/pthread_create.c                         |  16 +--
 nptl/pthread_kill.c                           |  10 +-
 nptl/pthread_sigmask.c                        |   2 +-
 rt/tst-timer-sigmask.c                        |   2 +-
 signal/sigaction.c                            |   2 +-
 signal/sigaddset.c                            |   2 +-
 signal/sigdelset.c                            |   2 +-
 signal/sigfillset.c                           |   2 +-
 stdlib/abort.c                                |  10 +-
 sysdeps/generic/internal-signals.h            |  31 +-----
 sysdeps/posix/signal.c                        |   2 +-
 sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c |   2 +-
 sysdeps/unix/sysv/linux/internal-signals.h    |  53 +++++----
 sysdeps/unix/sysv/linux/internal-sigset.h     | 105 ++++++++++++++++++
 sysdeps/unix/sysv/linux/spawni.c              |  14 ++-
 sysdeps/unix/sysv/linux/timer_routines.c      |   2 +-
 18 files changed, 178 insertions(+), 84 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/internal-sigset.h
  

Hi Adhemerval,

Overall, the patch looks mostly okay to me. I have some comments,
questions, and minor typos noted inline:

> The main drive is to optimize the internal usage and required size
> when sigset_t in embedded in other data structures.  On Linux, the

Typo: s/in/is/

> current supported signal set requires up to 8 bytes (16 on mips),
> wat lower than the user defined sigset_t (128 bytes).

Typo: was

> A new internal type internal_sigset_t is added, along with the
> functions to operate on it similar to the ones for sigset_t.  The
> internal-signals.h is also refactores to remove unused functions

Minor typo: refactored

> Besides small stack usage on some functions (posix_spawn, abort)
> it lower the struct pthread by about 120 bytes (112 on mips).
>
> Checked on x86_64-linux-gnu.

OK. I rebuilt the Fedora Rawhide glibc package with this patch a few
days ago and the testsuite run was clean.

> ---
>  nptl/descr.h                                  |   3 +-
>  nptl/pthread_attr_setsigmask.c                |   2 +-
>  nptl/pthread_create.c                         |  16 +--
>  nptl/pthread_kill.c                           |  10 +-
>  nptl/pthread_sigmask.c                        |   2 +-
>  rt/tst-timer-sigmask.c                        |   2 +-
>  signal/sigaction.c                            |   2 +-
>  signal/sigaddset.c                            |   2 +-
>  signal/sigdelset.c                            |   2 +-
>  signal/sigfillset.c                           |   2 +-
>  stdlib/abort.c                                |  10 +-
>  sysdeps/generic/internal-signals.h            |  31 +-----
>  sysdeps/posix/signal.c                        |   2 +-
>  sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c |   2 +-
>  sysdeps/unix/sysv/linux/internal-signals.h    |  53 +++++----
>  sysdeps/unix/sysv/linux/internal-sigset.h     | 105 ++++++++++++++++++
>  sysdeps/unix/sysv/linux/spawni.c              |  14 ++-
>  sysdeps/unix/sysv/linux/timer_routines.c      |   2 +-
>  18 files changed, 178 insertions(+), 84 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/internal-sigset.h
>
> diff --git a/nptl/descr.h b/nptl/descr.h
> index b5852632e3..5cacb286f3 100644
> --- a/nptl/descr.h
> +++ b/nptl/descr.h
> @@ -35,6 +35,7 @@
>  #include <kernel-features.h>
>  #include <tls-internal-struct.h>
>  #include <sys/rseq.h>
> +#include <internal-sigset.h>

OK. New header defining internal_sigset_t and functions that operate on it.

>
>  #ifndef TCB_ALIGNMENT
>  # define TCB_ALIGNMENT 32
> @@ -387,7 +388,7 @@ struct pthread
>    /* Signal mask for the new thread.  Used during thread startup to
>       restore the signal mask.  (Threads are launched with all signals
>       masked.)  */
> -  sigset_t sigmask;
> +  internal_sigset_t sigmask;

OK. Use newer, smaller struct.

>
>    /* Indicates whether is a C11 thread created by thrd_creat.  */
>    bool c11;

> diff --git a/sysdeps/generic/internal-signals.h b/sysdeps/generic/internal-signals.h
> index 6121c117ab..0c8f67f1a2 100644
> --- a/sysdeps/generic/internal-signals.h
> +++ b/sysdeps/generic/internal-signals.h

OK. Changes to the generic header.

> @@ -29,39 +29,20 @@
>  #define RESERVED_SIGRT  0
>
>  static inline bool
> -__is_internal_signal (int sig)
> +is_internal_signal (int sig)

OK. Renamed function that isn't visible externally.

>  {
>    return false;
>  }
>
>  static inline void
> -__clear_internal_signals (sigset_t *set)
> +clear_internal_signals (sigset_t *set)

OK. Same.

>  {
>  }
>
> -static inline void
> -__libc_signal_block_all (sigset_t *set)
> -{
> -  sigset_t allset;
> -  __sigfillset (&allset);
> -  __sigprocmask (SIG_BLOCK, &allset, set);
> -}

OK. Remove unused function.

> -
> -static inline void
> -__libc_signal_block_app (sigset_t *set)
> -{
> -  sigset_t allset;
> -  __sigfillset (&allset);
> -  __clear_internal_signals (&allset);
> -  __sigprocmask (SIG_BLOCK, &allset, set);
> -}

OK. Remove unused function.

> -
> -/* Restore current process signal mask.  */
> -static inline void
> -__libc_signal_restore_set (const sigset_t *set)
> -{
> -  __sigprocmask (SIG_SETMASK, set, NULL);
> -}

I noticed that nptl/pthread_{kill,create}.c use
internal_signal_restore_set which isn't defined in the generic header
any more. I also noticed that internal_sigfillset and
internal_sigdelset are in use but not defined by the generic header
any more. Am I missing something?

> +typedef sigset_t internal_sigset_t;

OK. In the generic version, internal_sigset_t is just an alias for
sigset_t. We continue to use the old type.

>
> +#define internal_sigemptyset(__s)            sigemptyset (__s)
> +#define internal_sigaddset(__s, __i)        sigaddset (__s, __i)
> +#define internal_sigprocmask(__h, __s, __o)  sigprocmask (__h, __s, __o)

OK. References to these three have been replaced by references to
internal_ versions in abort.c so we need those definitions.

>
>  #endif /* __INTERNAL_SIGNALS_H  */

> diff --git a/sysdeps/unix/sysv/linux/internal-signals.h b/sysdeps/unix/sysv/linux/internal-signals.h
> index f9efb6a159..96cfa0a962 100644
> --- a/sysdeps/unix/sysv/linux/internal-signals.h
> +++ b/sysdeps/unix/sysv/linux/internal-signals.h

OK. Changes to the linux specific header.

> @@ -19,10 +19,11 @@
>  #ifndef __INTERNAL_SIGNALS_H
>  # define __INTERNAL_SIGNALS_H
>
> +#include <internal-sigset.h>
> +#include <limits.h>
>  #include <signal.h>
>  #include <sigsetops.h>
>  #include <stdbool.h>
> -#include <limits.h>
>  #include <stddef.h>
>  #include <sysdep.h>
>
> @@ -47,49 +48,60 @@
>
>  /* Return is sig is used internally.  */
>  static inline bool
> -__is_internal_signal (int sig)
> +is_internal_signal (int sig)
>  {
>    return (sig == SIGCANCEL) || (sig == SIGSETXID);
>  }

OK. Dropped __ prefix in a function not visible externally.

>
>  /* Remove internal glibc signal from the mask.  */
>  static inline void
> -__clear_internal_signals (sigset_t *set)
> +clear_internal_signals (sigset_t *set)
>  {
>    __sigdelset (set, SIGCANCEL);
>    __sigdelset (set, SIGSETXID);
>  }

OK. Function renamed. I was momentarily confused by the "internal_" in
the name, with this patch being about internal_sigset_t - but I see
that the "internal" here refers to signals internally used by glibc.
Obviously, it continues to use the old type because that's how it is
still used.

>
> -static const sigset_t sigall_set = {
> -   .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 }
> +static const internal_sigset_t sigall_set = {
> +   .__val = {[0 ...  __NSIG_WORDS-1 ] =  -1 }
>  };

OK. sigall_set is now an internal_sigset and thus only NSIG_WORDS words long.

>
> -static const sigset_t sigtimer_set = {
> -  .__val = { [0]                      = __sigmask (SIGTIMER),
> -             [1 ... _SIGSET_NWORDS-1] = 0 }
> -};

OK. This definition was moved further down.

> +/* Obtain and changed blocked signals, including internal glibc ones.  */

Typo. Looks like it should be "Obtain and change".

> +static inline int
> +internal_sigprocmask (int how, const internal_sigset_t *set,
> +                     internal_sigset_t *oldset)
> +{
> +  return INTERNAL_SYSCALL_CALL (rt_sigprocmask, how, set, oldset,
> +                               __NSIG_BYTES);
> +}

OK. New internal function. Yes, internal_sigset_t is __NSIG_BYTES wide.

>
>  /* Block all signals, including internal glibc ones.  */
>  static inline void
> -__libc_signal_block_all (sigset_t *set)
> +internal_signal_block_all (internal_sigset_t *set)
>  {
>    INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigall_set, set,
>                          __NSIG_BYTES);
>  }

While we are changing things here, calling the argument 'oset' instead
of 'set' might be clearer as to its intent?

>
> -/* Block all application signals (excluding internal glibc ones).  */
> +/* Restore current process signal mask.  */
>  static inline void
> -__libc_signal_block_app (sigset_t *set)
> +internal_signal_restore_set (const internal_sigset_t *set)
>  {
> -  sigset_t allset = sigall_set;
> -  __clear_internal_signals (&allset);
> -  INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &allset, set,
> +  INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
>                          __NSIG_BYTES);
>  }

OK. signal_block_app is removed because it wasn't being used.

OK. internal_signal_restore_set replaces __libc_signal_restore_set;
uses the new type.

>
> +
> +/* It is used on timer_create code directly on sigwaitinfo call, so it can not
> +   use the internal_sigset_t definitions.  */
> +static const sigset_t sigtimer_set = {
> +  .__val = { [0]                      = __sigmask (SIGTIMER),
> +             [1 ... _SIGSET_NWORDS-1] = 0
> +  }
> +};

OK. This definition was moved down.

> +
>  /* Block only SIGTIMER and return the previous set on SET.  */
>  static inline void
> -__libc_signal_block_sigtimer (sigset_t *set)
> +signal_block_sigtimer (sigset_t *set)

Internal function renamed. But looks like it isn't used at all?

>  {
>    INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigtimer_set, set,
>                          __NSIG_BYTES);
> @@ -97,17 +109,10 @@ __libc_signal_block_sigtimer (sigset_t *set)
>
>  /* Unblock only SIGTIMER and return the previous set on SET.  */
>  static inline void
> -__libc_signal_unblock_sigtimer (sigset_t *set)
> +signal_unblock_sigtimer (sigset_t *set)

Internal function renamed. Looks like this is only ever used once with
a NULL argument and could be switched to internal_sigset_t for
consistency?

>  {
>    INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_UNBLOCK, &sigtimer_set, set,
>                          __NSIG_BYTES);
>  }
>
> -/* Restore current process signal mask.  */
> -static inline void
> -__libc_signal_restore_set (const sigset_t *set)
> -{
> -  INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
> -                        __NSIG_BYTES);
> -}

OK. This got replaced by internal_signal_restore_set.

>  #endif
> diff --git a/sysdeps/unix/sysv/linux/internal-sigset.h b/sysdeps/unix/sysv/linux/internal-sigset.h
> new file mode 100644
> index 0000000000..cdd7260b1c
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/internal-sigset.h
> @@ -0,0 +1,105 @@
> +/* Internal sigset_t definition.
> +   Copyright (C) 2022 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/>.  */
> +
> +#ifndef _INTERNAL_SIGSET_H
> +#define _INTERNAL_SIGSET_H
> +
> +#include <sigsetops.h>
> +
> +typedef struct
> +{
> +  unsigned long int __val[__NSIG_WORDS];
> +} internal_sigset_t;

OK. New internal structure that is only NSIG_WORDS words long.

> +
> +static inline void
> +internal_sigset_from_sigset (internal_sigset_t *iset, const sigset_t *set)
> +{
> +  int cnt = __NSIG_WORDS;
> +  while (--cnt >= 0)
> +   iset->__val[cnt] = set->__val[cnt];
> +}

OK. Converts sigset to internal_sigset. We only care about the first
NSIG_WORDS words.

> +
> +static inline void
> +internal_sigemptyset (internal_sigset_t *set)
> +{
> +  int cnt = __NSIG_WORDS;
> +  while (--cnt >= 0)
> +   set->__val[cnt] = 0;
> +}

OK.

> +
> +static inline void
> +internal_sigfillset (internal_sigset_t *set)
> +{
> +  int cnt = __NSIG_WORDS;
> +  while (--cnt >= 0)
> +   set->__val[cnt] = ~0UL;
> +}

OK.

> +
> +static inline int
> +internal_sigisemptyset (const internal_sigset_t *set)
> +{
> +  int cnt = __NSIG_WORDS;
> +  int ret = set->__val[--cnt];
> +  while (ret == 0 && --cnt >= 0)
> +    ret = set->__val[cnt];
> +  return ret == 0;
> +}

OK. Check each word (starting from the last) for zero. Stop checking
as soon as we see a non-zero.
I wonder if it's easier to read a `for' loop here instead.

> +
> +static inline void
> +internal_sigandset (internal_sigset_t *dest, const internal_sigset_t *left,
> +                   const internal_sigset_t *right)
> +{
> +  int cnt = __NSIG_WORDS;
> +  while (--cnt >= 0)
> +    dest->__val[cnt] = left->__val[cnt] & right->__val[cnt];
> +}

OK. Bitwise-and each word of left and right, and store it in dest.

> +
> +static inline void
> +internal_sigorset (internal_sigset_t *dest, const internal_sigset_t *left,
> +                  const internal_sigset_t *right)
> +{
> +  int cnt = __NSIG_WORDS;
> +  while (--cnt >= 0)
> +    dest->__val[cnt] = left->__val[cnt] | right->__val[cnt];
> +}

OK. Same for bitwise-or.

> +
> +static inline int
> +internal_sigismember (const internal_sigset_t *set, int sig)
> +{
> +  unsigned long int mask = __sigmask (sig);
> +  unsigned long int word = __sigword (sig);
> +  return set->__val[word] & mask ? 1 : 0;
> +}

OK.
sigmask returns the word containing sig from a mask where only sig is set.
sigword returns the index of the word containing sig.
Doing a bitwise-and of val[word] and mask will tell if the signal is set in val.

> +
> +static inline void
> +internal_sigaddset (internal_sigset_t *set, int sig)
> +{
> +  unsigned long int mask = __sigmask (sig);
> +  unsigned long int word = __sigword (sig);
> +  set->__val[word] |= mask;
> +}

OK.

> +
> +static inline void
> +internal_sigdelset (internal_sigset_t *set, int sig)
> +{
> +  unsigned long int mask = __sigmask (sig);
> +  unsigned long int word = __sigword (sig);
> +  set->__val[word] &= ~mask;
> +}

OK.

> +
> +#endif

Might be useful to include a comment referring to the corresponding #if here.

Moving on to changes that depend on the above code.

> diff --git a/nptl/pthread_attr_setsigmask.c b/nptl/pthread_attr_setsigmask.c
> index a6e650f4cc..908a0c13ef 100644
> --- a/nptl/pthread_attr_setsigmask.c
> +++ b/nptl/pthread_attr_setsigmask.c
> @@ -28,7 +28,7 @@ pthread_attr_setsigmask_np (pthread_attr_t *attr, const sigset_t *sigmask)
>
>    /* Filter out internal signals.  */
>    struct pthread_attr *iattr = (struct pthread_attr *) attr;
> -  __clear_internal_signals (&iattr->extension->sigmask);
> +  clear_internal_signals (&iattr->extension->sigmask);

OK. Function was renamed.

>
>    return 0;
>  }
> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> index e7a099acb7..360e78eb13 100644
> --- a/nptl/pthread_create.c
> +++ b/nptl/pthread_create.c
> @@ -423,7 +423,7 @@ start_thread (void *arg)
>        /* Store the new cleanup handler info.  */
>        THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
>
> -      __libc_signal_restore_set (&pd->sigmask);
> +      internal_signal_restore_set (&pd->sigmask);

OK. pd->sigmask is now internal_sigset_t.

>
>        LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
>
> @@ -501,8 +501,8 @@ start_thread (void *arg)
>       signal to be delivered.  (SIGSETXID cannot run application code,
>       nor does it use pthread_kill.)  Reuse the pd->sigmask space for
>       computing the signal mask, to save stack space.  */
> -  __sigfillset (&pd->sigmask);
> -  __sigdelset (&pd->sigmask, SIGSETXID);
> +  internal_sigfillset (&pd->sigmask);
> +  internal_sigdelset (&pd->sigmask, SIGSETXID);

OK. Switch to functions that operate on internal_sigset_t since
pd->sigmask is now of this type.

>    INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &pd->sigmask, NULL,
>                          __NSIG_BYTES);
>
> @@ -766,14 +766,14 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>    /* Block all signals, so that the new thread starts out with
>       signals disabled.  This avoids race conditions in the thread
>       startup.  */
> -  sigset_t original_sigmask;
> -  __libc_signal_block_all (&original_sigmask);
> +  internal_sigset_t original_sigmask;
> +  internal_signal_block_all (&original_sigmask);

OK. Use the new type.

>
>    if (iattr->extension != NULL && iattr->extension->sigmask_set)
>      /* Use the signal mask in the attribute.  The internal signals
>         have already been filtered by the public
>         pthread_attr_setsigmask_np interface.  */
> -    pd->sigmask = iattr->extension->sigmask;
> +    internal_sigset_from_sigset (&pd->sigmask, &iattr->extension->sigmask);

OK. Replace the assignment with conversion to internal type since
pd->sigmask is now an internal_sigset_t.

>    else
>      {
>        /* Conceptually, the new thread needs to inherit the signal mask
> @@ -783,7 +783,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>        pd->sigmask = original_sigmask;
>        /* Reset the cancellation signal mask in case this thread is
>          running cancellation.  */
> -      __sigdelset (&pd->sigmask, SIGCANCEL);
> +      internal_sigdelset (&pd->sigmask, SIGCANCEL);

OK.

>      }
>
>    /* Start the thread.  */
> @@ -830,7 +830,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>
>    /* Return to the previous signal mask, after creating the new
>       thread.  */
> -  __libc_signal_restore_set (&original_sigmask);
> +  internal_signal_restore_set (&original_sigmask);

OK. original_sigmask is now an internal_sigset_t.

>
>    if (__glibc_unlikely (retval != 0))
>      {
> diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c
> index 8015e10b70..178d38d3bd 100644
> --- a/nptl/pthread_kill.c
> +++ b/nptl/pthread_kill.c
> @@ -45,8 +45,8 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid)
>      }
>
>    /* Block all signals, as required by pd->exit_lock.  */
> -  sigset_t old_mask;
> -  __libc_signal_block_all (&old_mask);
> +  internal_sigset_t old_mask;
> +  internal_signal_block_all (&old_mask);

OK. Use new type.

>    __libc_lock_lock (pd->exit_lock);
>
>    int ret;
> @@ -64,7 +64,7 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid)
>      }
>
>    __libc_lock_unlock (pd->exit_lock);
> -  __libc_signal_restore_set (&old_mask);
> +  internal_signal_restore_set (&old_mask);

OK. Use new function for new type.

>
>    return ret;
>  }
> @@ -83,7 +83,7 @@ __pthread_kill (pthread_t threadid, int signo)
>  {
>    /* Disallow sending the signal we use for cancellation, timers,
>       for the setxid implementation.  */
> -  if (__is_internal_signal (signo))
> +  if (is_internal_signal (signo))

OK. Function was renamed.

>      return EINVAL;
>
>    return __pthread_kill_internal (threadid, signo);
> @@ -102,7 +102,7 @@ int
>  attribute_compat_text_section
>  __pthread_kill_esrch (pthread_t threadid, int signo)
>  {
> -  if (__is_internal_signal (signo))
> +  if (is_internal_signal (signo))

OK.

>      return EINVAL;
>
>    return __pthread_kill_implementation (threadid, signo, ESRCH);
> diff --git a/nptl/pthread_sigmask.c b/nptl/pthread_sigmask.c
> index 20f811cc6b..977740b97e 100644
> --- a/nptl/pthread_sigmask.c
> +++ b/nptl/pthread_sigmask.c
> @@ -32,7 +32,7 @@ __pthread_sigmask (int how, const sigset_t *newmask, sigset_t *oldmask)
>           || __glibc_unlikely (__sigismember (newmask, SIGSETXID))))
>      {
>        local_newmask = *newmask;
> -      __clear_internal_signals (&local_newmask);
> +      clear_internal_signals (&local_newmask);

OK. Function was renamed.

>        newmask = &local_newmask;
>      }
>
> diff --git a/rt/tst-timer-sigmask.c b/rt/tst-timer-sigmask.c
> index 11acb670ab..4d088a691d 100644
> --- a/rt/tst-timer-sigmask.c
> +++ b/rt/tst-timer-sigmask.c
> @@ -43,7 +43,7 @@ thread_handler (union sigval sv)
>        if (sigismember (&ss, sig))
>         {
>           TEST_VERIFY (sig != SIGKILL && sig != SIGSTOP);
> -         TEST_VERIFY (!__is_internal_signal (sig));
> +         TEST_VERIFY (!is_internal_signal (sig));

OK. Function was renamed.

>         }
>        if (test_verbose && sigismember (&ss, sig))
>         printf ("%d, ", sig);
> diff --git a/signal/sigaction.c b/signal/sigaction.c
> index 8e94b9a10b..d56b3196ca 100644
> --- a/signal/sigaction.c
> +++ b/signal/sigaction.c
> @@ -24,7 +24,7 @@
>  int
>  __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
>  {
> -  if (sig <= 0 || sig >= NSIG || __is_internal_signal (sig))
> +  if (sig <= 0 || sig >= NSIG || is_internal_signal (sig))

OK. Function was renamed.

>      {
>        __set_errno (EINVAL);
>        return -1;
> diff --git a/signal/sigaddset.c b/signal/sigaddset.c
> index c6ef0a953a..f0fed84dd7 100644
> --- a/signal/sigaddset.c
> +++ b/signal/sigaddset.c
> @@ -25,7 +25,7 @@ int
>  sigaddset (sigset_t *set, int signo)
>  {
>    if (set == NULL || signo <= 0 || signo >= NSIG
> -      || __is_internal_signal (signo))
> +      || is_internal_signal (signo))

OK. Function was renamed.

>      {
>        __set_errno (EINVAL);
>        return -1;
> diff --git a/signal/sigdelset.c b/signal/sigdelset.c
> index 81bb9a908a..2c973c9b84 100644
> --- a/signal/sigdelset.c
> +++ b/signal/sigdelset.c
> @@ -25,7 +25,7 @@ int
>  sigdelset (sigset_t *set, int signo)
>  {
>    if (set == NULL || signo <= 0 || signo >= NSIG
> -      || __is_internal_signal (signo))
> +      || is_internal_signal (signo))

OK. Function was renamed.

>      {
>        __set_errno (EINVAL);
>        return -1;
> diff --git a/signal/sigfillset.c b/signal/sigfillset.c
> index b52ef06aa0..1d11ae4fec 100644
> --- a/signal/sigfillset.c
> +++ b/signal/sigfillset.c
> @@ -31,7 +31,7 @@ sigfillset (sigset_t *set)
>      }
>
>    __sigfillset (set);
> -  __clear_internal_signals (set);
> +  clear_internal_signals (set);

OK. Function was renamed.

>    return 0;
>  }
>  libc_hidden_def (sigfillset)
> diff --git a/stdlib/abort.c b/stdlib/abort.c
> index bcf72f9356..9c1065af0e 100644
> --- a/stdlib/abort.c
> +++ b/stdlib/abort.c
> @@ -21,7 +21,7 @@
>  #include <stdlib.h>
>  #include <string.h>
>  #include <unistd.h>
> -#include <sigsetops.h>
> +#include <internal-signals.h>

OK. We will be operating on internal_sigset_t.

>
>  /* Try to get a machine dependent instruction which will make the
>     program crash.  This is used in case everything else fails.  */
> @@ -48,7 +48,6 @@ void
>  abort (void)
>  {
>    struct sigaction act;
> -  sigset_t sigs;

OK. Declared later.

>
>    /* First acquire the lock.  */
>    __libc_lock_lock_recursive (lock);
> @@ -59,9 +58,10 @@ abort (void)
>    if (stage == 0)
>      {
>        ++stage;
> -      __sigemptyset (&sigs);
> -      __sigaddset (&sigs, SIGABRT);
> -      __sigprocmask (SIG_UNBLOCK, &sigs, 0);
> +      internal_sigset_t sigs;
> +      internal_sigemptyset (&sigs);
> +      internal_sigaddset (&sigs, SIGABRT);
> +      internal_sigprocmask (SIG_UNBLOCK, &sigs, NULL);
>      }

OK. Use new type and functions.

>
>    /* Send signal which possibly calls a user handler.  */

> diff --git a/sysdeps/posix/signal.c b/sysdeps/posix/signal.c
> index 8f17b4278d..88c3757126 100644
> --- a/sysdeps/posix/signal.c
> +++ b/sysdeps/posix/signal.c
> @@ -32,7 +32,7 @@ __bsd_signal (int sig, __sighandler_t handler)
>
>    /* Check signal extents to protect __sigismember.  */
>    if (handler == SIG_ERR || sig < 1 || sig >= NSIG
> -      || __is_internal_signal (sig))
> +      || is_internal_signal (sig))

OK.

>      {
>        __set_errno (EINVAL);
>        return SIG_ERR;
> diff --git a/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c b/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
> index a59ad78036..a53ae79965 100644
> --- a/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
> +++ b/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
> @@ -34,7 +34,7 @@ __libc_unwind_longjmp (sigjmp_buf env, int val)
>
>    if (env[0].__mask_was_saved)
>      /* Restore the saved signal mask.  */
> -    __libc_signal_restore_set (&env[0].__saved_mask);
> +    __sigprocmask (SIG_SETMASK, &env[0].__saved_mask, NULL);

OK. internal_signal_restore_set operates on internal_sigset_t, but
here we have a sigset_t. __saved_mask is a sigset_t, so we cannot use
it here. Instead, we directly call sigprocmask like we did in
__libc_signal_restore_set.

>
>    /* Call the machine-dependent function to restore machine state.  */
>    __sigstack_longjmp (env[0].__jmpbuf, val ?: 1);

> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
> index d703485e3f..75f5c06e32 100644
> --- a/sysdeps/unix/sysv/linux/spawni.c
> +++ b/sysdeps/unix/sysv/linux/spawni.c
> @@ -57,7 +57,7 @@
>
>  struct posix_spawn_args
>  {
> -  sigset_t oldmask;
> +  internal_sigset_t oldmask;

OK.

>    const char *file;
>    int (*exec) (const char *, char *const *, char *const *);
>    const posix_spawn_file_actions_t *fa;
> @@ -124,7 +124,7 @@ __spawni_child (void *arguments)
>         }
>        else if (__sigismember (&hset, sig))
>         {
> -         if (__is_internal_signal (sig))
> +         if (is_internal_signal (sig))

OK.

>             sa.sa_handler = SIG_IGN;
>           else
>             {
> @@ -284,8 +284,10 @@ __spawni_child (void *arguments)
>
>    /* Set the initial signal mask of the child if POSIX_SPAWN_SETSIGMASK
>       is set, otherwise restore the previous one.  */
> -  __sigprocmask (SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
> -                ? &attr->__ss : &args->oldmask, 0);
> +  if (attr->__flags & POSIX_SPAWN_SETSIGMASK)
> +    __sigprocmask (SIG_SETMASK, &attr->__ss, NULL);
> +  else
> +    internal_sigprocmask (SIG_SETMASK, &args->oldmask, NULL);

OK. One is a sigset_t and the other is an internal_sigset_t, so we
write this differently now. It's also more readable than the "?:"
version.

>
>    args->exec (args->file, args->argv, args->envp);
>
> @@ -368,7 +370,7 @@ __spawnix (pid_t * pid, const char *file,
>    args.envp = envp;
>    args.xflags = xflags;
>
> -  __libc_signal_block_all (&args.oldmask);
> +  internal_signal_block_all (&args.oldmask);

OK.

>
>    /* The clone flags used will create a new child that will run in the same
>       memory space (CLONE_VM) and the execution of calling thread will be
> @@ -416,7 +418,7 @@ __spawnix (pid_t * pid, const char *file,
>    if ((ec == 0) && (pid != NULL))
>      *pid = new_pid;
>
> -  __libc_signal_restore_set (&args.oldmask);
> +  internal_signal_restore_set (&args.oldmask);

OK.

>
>    __pthread_setcancelstate (state, NULL);
>
> diff --git a/sysdeps/unix/sysv/linux/timer_routines.c b/sysdeps/unix/sysv/linux/timer_routines.c
> index 8f0a2f635d..fc3deb6823 100644
> --- a/sysdeps/unix/sysv/linux/timer_routines.c
> +++ b/sysdeps/unix/sysv/linux/timer_routines.c
> @@ -41,7 +41,7 @@ struct thread_start_data
>  static void *
>  timer_sigev_thread (void *arg)
>  {
> -  __libc_signal_unblock_sigtimer (NULL);
> +  signal_unblock_sigtimer (NULL);

OK.

>
>    struct thread_start_data *td = (struct thread_start_data *) arg;
>    void (*thrfunc) (sigval_t) = td->thrfunc;
> --
> 2.34.1
>
  

> On 28 Jun 2022, at 14:16, Arjun Shankar <arjun@redhat.com> wrote:
> 
> Hi Adhemerval,
> 
> Overall, the patch looks mostly okay to me. I have some comments,
> questions, and minor typos noted inline:
> 
>> The main drive is to optimize the internal usage and required size
>> when sigset_t in embedded in other data structures. On Linux, the
> 
> Typo: s/in/is/

Ack.

> 
>> current supported signal set requires up to 8 bytes (16 on mips),
>> wat lower than the user defined sigset_t (128 bytes).
> 
> Typo: was

Ack.

> 
>> A new internal type internal_sigset_t is added, along with the
>> functions to operate on it similar to the ones for sigset_t. The
>> internal-signals.h is also refactores to remove unused functions
> 
> Minor typo: refactored

Ack.

> 
>> Besides small stack usage on some functions (posix_spawn, abort)
>> it lower the struct pthread by about 120 bytes (112 on mips).
>> 
>> Checked on x86_64-linux-gnu.
> 
> OK. I rebuilt the Fedora Rawhide glibc package with this patch a few
> days ago and the testsuite run was clean.

Thanks for the review, I will send an updated version.

> 
>> ---
>> nptl/descr.h | 3 +-
>> nptl/pthread_attr_setsigmask.c | 2 +-
>> nptl/pthread_create.c | 16 +--
>> nptl/pthread_kill.c | 10 +-
>> nptl/pthread_sigmask.c | 2 +-
>> rt/tst-timer-sigmask.c | 2 +-
>> signal/sigaction.c | 2 +-
>> signal/sigaddset.c | 2 +-
>> signal/sigdelset.c | 2 +-
>> signal/sigfillset.c | 2 +-
>> stdlib/abort.c | 10 +-
>> sysdeps/generic/internal-signals.h | 31 +-----
>> sysdeps/posix/signal.c | 2 +-
>> sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c | 2 +-
>> sysdeps/unix/sysv/linux/internal-signals.h | 53 +++++----
>> sysdeps/unix/sysv/linux/internal-sigset.h | 105 ++++++++++++++++++
>> sysdeps/unix/sysv/linux/spawni.c | 14 ++-
>> sysdeps/unix/sysv/linux/timer_routines.c | 2 +-
>> 18 files changed, 178 insertions(+), 84 deletions(-)
>> create mode 100644 sysdeps/unix/sysv/linux/internal-sigset.h
>> 
>> diff --git a/nptl/descr.h b/nptl/descr.h
>> index b5852632e3..5cacb286f3 100644
>> --- a/nptl/descr.h
>> +++ b/nptl/descr.h
>> @@ -35,6 +35,7 @@
>> #include <kernel-features.h>
>> #include <tls-internal-struct.h>
>> #include <sys/rseq.h>
>> +#include <internal-sigset.h>
> 
> OK. New header defining internal_sigset_t and functions that operate on it.
> 
>> 
>> #ifndef TCB_ALIGNMENT
>> # define TCB_ALIGNMENT 32
>> @@ -387,7 +388,7 @@ struct pthread
>> /* Signal mask for the new thread. Used during thread startup to
>> restore the signal mask. (Threads are launched with all signals
>> masked.) */
>> - sigset_t sigmask;
>> + internal_sigset_t sigmask;
> 
> OK. Use newer, smaller struct.
> 
>> 
>> /* Indicates whether is a C11 thread created by thrd_creat. */
>> bool c11;
> 
>> diff --git a/sysdeps/generic/internal-signals.h b/sysdeps/generic/internal-signals.h
>> index 6121c117ab..0c8f67f1a2 100644
>> --- a/sysdeps/generic/internal-signals.h
>> +++ b/sysdeps/generic/internal-signals.h
> 
> OK. Changes to the generic header.
> 
>> @@ -29,39 +29,20 @@
>> #define RESERVED_SIGRT 0
>> 
>> static inline bool
>> -__is_internal_signal (int sig)
>> +is_internal_signal (int sig)
> 
> OK. Renamed function that isn't visible externally.
> 
>> {
>> return false;
>> }
>> 
>> static inline void
>> -__clear_internal_signals (sigset_t *set)
>> +clear_internal_signals (sigset_t *set)
> 
> OK. Same.
> 
>> {
>> }
>> 
>> -static inline void
>> -__libc_signal_block_all (sigset_t *set)
>> -{
>> - sigset_t allset;
>> - __sigfillset (&allset);
>> - __sigprocmask (SIG_BLOCK, &allset, set);
>> -}
> 
> OK. Remove unused function.
> 
>> -
>> -static inline void
>> -__libc_signal_block_app (sigset_t *set)
>> -{
>> - sigset_t allset;
>> - __sigfillset (&allset);
>> - __clear_internal_signals (&allset);
>> - __sigprocmask (SIG_BLOCK, &allset, set);
>> -}
> 
> OK. Remove unused function.
> 
>> -
>> -/* Restore current process signal mask. */
>> -static inline void
>> -__libc_signal_restore_set (const sigset_t *set)
>> -{
>> - __sigprocmask (SIG_SETMASK, set, NULL);
>> -}
> 
> I noticed that nptl/pthread_{kill,create}.c use
> internal_signal_restore_set which isn't defined in the generic header
> any more. I also noticed that internal_sigfillset and
> internal_sigdelset are in use but not defined by the generic header
> any more. Am I missing something?

The nptl folder is in fact a Linux specific implementation of pthread, so
for a non-Linux possible port it won’t be used as default (as Hurd does 
with the htl).  All the new internal signal usage are restricted to nptl 
or Linux implementations:

$ git grep internal_signal_restore_set
nptl/pthread_create.c:      internal_signal_restore_set (&pd->sigmask);
nptl/pthread_create.c:  internal_signal_restore_set (&original_sigmask);
nptl/pthread_kill.c:  internal_signal_restore_set (&old_mask);
sysdeps/unix/sysv/linux/internal-signals.h:internal_signal_restore_set (const internal_sigset_t *set)
sysdeps/unix/sysv/linux/spawni.c:  internal_signal_restore_set (&args.oldmask);

$ git grep internal_sigfillset
nptl/pthread_create.c:  internal_sigfillset (&pd->sigmask);
sysdeps/unix/sysv/linux/internal-sigset.h:internal_sigfillset (internal_sigset_t *set)

$ git grep internal_sigdelset
nptl/pthread_create.c:  internal_sigdelset (&pd->sigmask, SIGSETXID);
nptl/pthread_create.c:      internal_sigdelset (&pd->sigmask, SIGCANCEL);
sysdeps/unix/sysv/linux/internal-sigset.h:internal_sigdelset (internal_sigset_t *set, int sig)

> 
>> +typedef sigset_t internal_sigset_t;
> 
> OK. In the generic version, internal_sigset_t is just an alias for
> sigset_t. We continue to use the old type.
> 
>> 
>> +#define internal_sigemptyset(__s) sigemptyset (__s)
>> +#define internal_sigaddset(__s, __i) sigaddset (__s, __i)
>> +#define internal_sigprocmask(__h, __s, __o) sigprocmask (__h, __s, __o)
> 
> OK. References to these three have been replaced by references to
> internal_ versions in abort.c so we need those definitions.
> 
>> 
>> #endif /* __INTERNAL_SIGNALS_H */
> 
>> diff --git a/sysdeps/unix/sysv/linux/internal-signals.h b/sysdeps/unix/sysv/linux/internal-signals.h
>> index f9efb6a159..96cfa0a962 100644
>> --- a/sysdeps/unix/sysv/linux/internal-signals.h
>> +++ b/sysdeps/unix/sysv/linux/internal-signals.h
> 
> OK. Changes to the linux specific header.
> 
>> @@ -19,10 +19,11 @@
>> #ifndef __INTERNAL_SIGNALS_H
>> # define __INTERNAL_SIGNALS_H
>> 
>> +#include <internal-sigset.h>
>> +#include <limits.h>
>> #include <signal.h>
>> #include <sigsetops.h>
>> #include <stdbool.h>
>> -#include <limits.h>
>> #include <stddef.h>
>> #include <sysdep.h>
>> 
>> @@ -47,49 +48,60 @@
>> 
>> /* Return is sig is used internally. */
>> static inline bool
>> -__is_internal_signal (int sig)
>> +is_internal_signal (int sig)
>> {
>> return (sig == SIGCANCEL) || (sig == SIGSETXID);
>> }
> 
> OK. Dropped __ prefix in a function not visible externally.
> 
>> 
>> /* Remove internal glibc signal from the mask. */
>> static inline void
>> -__clear_internal_signals (sigset_t *set)
>> +clear_internal_signals (sigset_t *set)
>> {
>> __sigdelset (set, SIGCANCEL);
>> __sigdelset (set, SIGSETXID);
>> }
> 
> OK. Function renamed. I was momentarily confused by the "internal_" in
> the name, with this patch being about internal_sigset_t - but I see
> that the "internal" here refers to signals internally used by glibc.
> Obviously, it continues to use the old type because that's how it is
> still used.

Yeah, I used the internal_ prefix for the function that operate on the
new internal_sigset_t.

> 
>> 
>> -static const sigset_t sigall_set = {
>> - .__val = {[0 ... _SIGSET_NWORDS-1 ] = -1 }
>> +static const internal_sigset_t sigall_set = {
>> + .__val = {[0 ... __NSIG_WORDS-1 ] = -1 }
>> };
> 
> OK. sigall_set is now an internal_sigset and thus only NSIG_WORDS words long.
> 
>> 
>> -static const sigset_t sigtimer_set = {
>> - .__val = { [0] = __sigmask (SIGTIMER),
>> - [1 ... _SIGSET_NWORDS-1] = 0 }
>> -};
> 
> OK. This definition was moved further down.
> 
>> +/* Obtain and changed blocked signals, including internal glibc ones. */
> 
> Typo. Looks like it should be "Obtain and change".

Ack.

> 
>> +static inline int
>> +internal_sigprocmask (int how, const internal_sigset_t *set,
>> + internal_sigset_t *oldset)
>> +{
>> + return INTERNAL_SYSCALL_CALL (rt_sigprocmask, how, set, oldset,
>> + __NSIG_BYTES);
>> +}
> 
> OK. New internal function. Yes, internal_sigset_t is __NSIG_BYTES wide.
> 
>> 
>> /* Block all signals, including internal glibc ones. */
>> static inline void
>> -__libc_signal_block_all (sigset_t *set)
>> +internal_signal_block_all (internal_sigset_t *set)
>> {
>> INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigall_set, set,
>> __NSIG_BYTES);
>> }
> 
> While we are changing things here, calling the argument 'oset' instead
> of 'set' might be clearer as to its intent?

It does make sense.

> 
>> 
>> -/* Block all application signals (excluding internal glibc ones). */
>> +/* Restore current process signal mask. */
>> static inline void
>> -__libc_signal_block_app (sigset_t *set)
>> +internal_signal_restore_set (const internal_sigset_t *set)
>> {
>> - sigset_t allset = sigall_set;
>> - __clear_internal_signals (&allset);
>> - INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &allset, set,
>> + INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
>> __NSIG_BYTES);
>> }
> 
> OK. signal_block_app is removed because it wasn't being used.
> 
> OK. internal_signal_restore_set replaces __libc_signal_restore_set;
> uses the new type.
> 
>> 
>> +
>> +/* It is used on timer_create code directly on sigwaitinfo call, so it can not
>> + use the internal_sigset_t definitions. */
>> +static const sigset_t sigtimer_set = {
>> + .__val = { [0] = __sigmask (SIGTIMER),
>> + [1 ... _SIGSET_NWORDS-1] = 0
>> + }
>> +};
> 
> OK. This definition was moved down.
> 
>> +
>> /* Block only SIGTIMER and return the previous set on SET. */
>> static inline void
>> -__libc_signal_block_sigtimer (sigset_t *set)
>> +signal_block_sigtimer (sigset_t *set)
> 
> Internal function renamed. But looks like it isn't used at all?

Indeed, I will remove it.

> 
>> {
>> INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigtimer_set, set,
>> __NSIG_BYTES);
>> @@ -97,17 +109,10 @@ __libc_signal_block_sigtimer (sigset_t *set)
>> 
>> /* Unblock only SIGTIMER and return the previous set on SET. */
>> static inline void
>> -__libc_signal_unblock_sigtimer (sigset_t *set)
>> +signal_unblock_sigtimer (sigset_t *set)
> 
> Internal function renamed. Looks like this is only ever used once with
> a NULL argument and could be switched to internal_sigset_t for
> consistency?

Right, I think it would be better to just remove the argument (we can add
it later if it is really required).

> 
>> {
>> INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_UNBLOCK, &sigtimer_set, set,
>> __NSIG_BYTES);
>> }
>> 
>> -/* Restore current process signal mask. */
>> -static inline void
>> -__libc_signal_restore_set (const sigset_t *set)
>> -{
>> - INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
>> - __NSIG_BYTES);
>> -}
> 
> OK. This got replaced by internal_signal_restore_set.
> 
>> #endif
>> diff --git a/sysdeps/unix/sysv/linux/internal-sigset.h b/sysdeps/unix/sysv/linux/internal-sigset.h
>> new file mode 100644
>> index 0000000000..cdd7260b1c
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/internal-sigset.h
>> @@ -0,0 +1,105 @@
>> +/* Internal sigset_t definition.
>> + Copyright (C) 2022 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/>. */
>> +
>> +#ifndef _INTERNAL_SIGSET_H
>> +#define _INTERNAL_SIGSET_H
>> +
>> +#include <sigsetops.h>
>> +
>> +typedef struct
>> +{
>> + unsigned long int __val[__NSIG_WORDS];
>> +} internal_sigset_t;
> 
> OK. New internal structure that is only NSIG_WORDS words long.
> 
>> +
>> +static inline void
>> +internal_sigset_from_sigset (internal_sigset_t *iset, const sigset_t *set)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + while (--cnt >= 0)
>> + iset->__val[cnt] = set->__val[cnt];
>> +}
> 
> OK. Converts sigset to internal_sigset. We only care about the first
> NSIG_WORDS words.
> 
>> +
>> +static inline void
>> +internal_sigemptyset (internal_sigset_t *set)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + while (--cnt >= 0)
>> + set->__val[cnt] = 0;
>> +}
> 
> OK.
> 
>> +
>> +static inline void
>> +internal_sigfillset (internal_sigset_t *set)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + while (--cnt >= 0)
>> + set->__val[cnt] = ~0UL;
>> +}
> 
> OK.
> 
>> +
>> +static inline int
>> +internal_sigisemptyset (const internal_sigset_t *set)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + int ret = set->__val[--cnt];
>> + while (ret == 0 && --cnt >= 0)
>> + ret = set->__val[cnt];
>> + return ret == 0;
>> +}
> 
> OK. Check each word (starting from the last) for zero. Stop checking
> as soon as we see a non-zero.
> I wonder if it's easier to read a `for' loop here instead.
> 
>> +
>> +static inline void
>> +internal_sigandset (internal_sigset_t *dest, const internal_sigset_t *left,
>> + const internal_sigset_t *right)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + while (--cnt >= 0)
>> + dest->__val[cnt] = left->__val[cnt] & right->__val[cnt];
>> +}
> 
> OK. Bitwise-and each word of left and right, and store it in dest.
> 
>> +
>> +static inline void
>> +internal_sigorset (internal_sigset_t *dest, const internal_sigset_t *left,
>> + const internal_sigset_t *right)
>> +{
>> + int cnt = __NSIG_WORDS;
>> + while (--cnt >= 0)
>> + dest->__val[cnt] = left->__val[cnt] | right->__val[cnt];
>> +}
> 
> OK. Same for bitwise-or.
> 
>> +
>> +static inline int
>> +internal_sigismember (const internal_sigset_t *set, int sig)
>> +{
>> + unsigned long int mask = __sigmask (sig);
>> + unsigned long int word = __sigword (sig);
>> + return set->__val[word] & mask ? 1 : 0;
>> +}
> 
> OK.
> sigmask returns the word containing sig from a mask where only sig is set.
> sigword returns the index of the word containing sig.
> Doing a bitwise-and of val[word] and mask will tell if the signal is set in val.
> 
>> +
>> +static inline void
>> +internal_sigaddset (internal_sigset_t *set, int sig)
>> +{
>> + unsigned long int mask = __sigmask (sig);
>> + unsigned long int word = __sigword (sig);
>> + set->__val[word] |= mask;
>> +}
> 
> OK.
> 
>> +
>> +static inline void
>> +internal_sigdelset (internal_sigset_t *set, int sig)
>> +{
>> + unsigned long int mask = __sigmask (sig);
>> + unsigned long int word = __sigword (sig);
>> + set->__val[word] &= ~mask;
>> +}
> 
> OK.
> 
>> +
>> +#endif
> 
> Might be useful to include a comment referring to the corresponding #if here.

Ack.

> 
> Moving on to changes that depend on the above code.
> 
>> diff --git a/nptl/pthread_attr_setsigmask.c b/nptl/pthread_attr_setsigmask.c
>> index a6e650f4cc..908a0c13ef 100644
>> --- a/nptl/pthread_attr_setsigmask.c
>> +++ b/nptl/pthread_attr_setsigmask.c
>> @@ -28,7 +28,7 @@ pthread_attr_setsigmask_np (pthread_attr_t *attr, const sigset_t *sigmask)
>> 
>> /* Filter out internal signals. */
>> struct pthread_attr *iattr = (struct pthread_attr *) attr;
>> - __clear_internal_signals (&iattr->extension->sigmask);
>> + clear_internal_signals (&iattr->extension->sigmask);
> 
> OK. Function was renamed.
> 
>> 
>> return 0;
>> }
>> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
>> index e7a099acb7..360e78eb13 100644
>> --- a/nptl/pthread_create.c
>> +++ b/nptl/pthread_create.c
>> @@ -423,7 +423,7 @@ start_thread (void *arg)
>> /* Store the new cleanup handler info. */
>> THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
>> 
>> - __libc_signal_restore_set (&pd->sigmask);
>> + internal_signal_restore_set (&pd->sigmask);
> 
> OK. pd->sigmask is now internal_sigset_t.
> 
>> 
>> LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
>> 
>> @@ -501,8 +501,8 @@ start_thread (void *arg)
>> signal to be delivered. (SIGSETXID cannot run application code,
>> nor does it use pthread_kill.) Reuse the pd->sigmask space for
>> computing the signal mask, to save stack space. */
>> - __sigfillset (&pd->sigmask);
>> - __sigdelset (&pd->sigmask, SIGSETXID);
>> + internal_sigfillset (&pd->sigmask);
>> + internal_sigdelset (&pd->sigmask, SIGSETXID);
> 
> OK. Switch to functions that operate on internal_sigset_t since
> pd->sigmask is now of this type.
> 
>> INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &pd->sigmask, NULL,
>> __NSIG_BYTES);
>> 
>> @@ -766,14 +766,14 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>> /* Block all signals, so that the new thread starts out with
>> signals disabled. This avoids race conditions in the thread
>> startup. */
>> - sigset_t original_sigmask;
>> - __libc_signal_block_all (&original_sigmask);
>> + internal_sigset_t original_sigmask;
>> + internal_signal_block_all (&original_sigmask);
> 
> OK. Use the new type.
> 
>> 
>> if (iattr->extension != NULL && iattr->extension->sigmask_set)
>> /* Use the signal mask in the attribute. The internal signals
>> have already been filtered by the public
>> pthread_attr_setsigmask_np interface. */
>> - pd->sigmask = iattr->extension->sigmask;
>> + internal_sigset_from_sigset (&pd->sigmask, &iattr->extension->sigmask);
> 
> OK. Replace the assignment with conversion to internal type since
> pd->sigmask is now an internal_sigset_t.
> 
>> else
>> {
>> /* Conceptually, the new thread needs to inherit the signal mask
>> @@ -783,7 +783,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>> pd->sigmask = original_sigmask;
>> /* Reset the cancellation signal mask in case this thread is
>> running cancellation. */
>> - __sigdelset (&pd->sigmask, SIGCANCEL);
>> + internal_sigdelset (&pd->sigmask, SIGCANCEL);
> 
> OK.
> 
>> }
>> 
>> /* Start the thread. */
>> @@ -830,7 +830,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
>> 
>> /* Return to the previous signal mask, after creating the new
>> thread. */
>> - __libc_signal_restore_set (&original_sigmask);
>> + internal_signal_restore_set (&original_sigmask);
> 
> OK. original_sigmask is now an internal_sigset_t.
> 
>> 
>> if (__glibc_unlikely (retval != 0))
>> {
>> diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c
>> index 8015e10b70..178d38d3bd 100644
>> --- a/nptl/pthread_kill.c
>> +++ b/nptl/pthread_kill.c
>> @@ -45,8 +45,8 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid)
>> }
>> 
>> /* Block all signals, as required by pd->exit_lock. */
>> - sigset_t old_mask;
>> - __libc_signal_block_all (&old_mask);
>> + internal_sigset_t old_mask;
>> + internal_signal_block_all (&old_mask);
> 
> OK. Use new type.
> 
>> __libc_lock_lock (pd->exit_lock);
>> 
>> int ret;
>> @@ -64,7 +64,7 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid)
>> }
>> 
>> __libc_lock_unlock (pd->exit_lock);
>> - __libc_signal_restore_set (&old_mask);
>> + internal_signal_restore_set (&old_mask);
> 
> OK. Use new function for new type.
> 
>> 
>> return ret;
>> }
>> @@ -83,7 +83,7 @@ __pthread_kill (pthread_t threadid, int signo)
>> {
>> /* Disallow sending the signal we use for cancellation, timers,
>> for the setxid implementation. */
>> - if (__is_internal_signal (signo))
>> + if (is_internal_signal (signo))
> 
> OK. Function was renamed.
> 
>> return EINVAL;
>> 
>> return __pthread_kill_internal (threadid, signo);
>> @@ -102,7 +102,7 @@ int
>> attribute_compat_text_section
>> __pthread_kill_esrch (pthread_t threadid, int signo)
>> {
>> - if (__is_internal_signal (signo))
>> + if (is_internal_signal (signo))
> 
> OK.
> 
>> return EINVAL;
>> 
>> return __pthread_kill_implementation (threadid, signo, ESRCH);
>> diff --git a/nptl/pthread_sigmask.c b/nptl/pthread_sigmask.c
>> index 20f811cc6b..977740b97e 100644
>> --- a/nptl/pthread_sigmask.c
>> +++ b/nptl/pthread_sigmask.c
>> @@ -32,7 +32,7 @@ __pthread_sigmask (int how, const sigset_t *newmask, sigset_t *oldmask)
>> || __glibc_unlikely (__sigismember (newmask, SIGSETXID))))
>> {
>> local_newmask = *newmask;
>> - __clear_internal_signals (&local_newmask);
>> + clear_internal_signals (&local_newmask);
> 
> OK. Function was renamed.
> 
>> newmask = &local_newmask;
>> }
>> 
>> diff --git a/rt/tst-timer-sigmask.c b/rt/tst-timer-sigmask.c
>> index 11acb670ab..4d088a691d 100644
>> --- a/rt/tst-timer-sigmask.c
>> +++ b/rt/tst-timer-sigmask.c
>> @@ -43,7 +43,7 @@ thread_handler (union sigval sv)
>> if (sigismember (&ss, sig))
>> {
>> TEST_VERIFY (sig != SIGKILL && sig != SIGSTOP);
>> - TEST_VERIFY (!__is_internal_signal (sig));
>> + TEST_VERIFY (!is_internal_signal (sig));
> 
> OK. Function was renamed.
> 
>> }
>> if (test_verbose && sigismember (&ss, sig))
>> printf ("%d, ", sig);
>> diff --git a/signal/sigaction.c b/signal/sigaction.c
>> index 8e94b9a10b..d56b3196ca 100644
>> --- a/signal/sigaction.c
>> +++ b/signal/sigaction.c
>> @@ -24,7 +24,7 @@
>> int
>> __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
>> {
>> - if (sig <= 0 || sig >= NSIG || __is_internal_signal (sig))
>> + if (sig <= 0 || sig >= NSIG || is_internal_signal (sig))
> 
> OK. Function was renamed.
> 
>> {
>> __set_errno (EINVAL);
>> return -1;
>> diff --git a/signal/sigaddset.c b/signal/sigaddset.c
>> index c6ef0a953a..f0fed84dd7 100644
>> --- a/signal/sigaddset.c
>> +++ b/signal/sigaddset.c
>> @@ -25,7 +25,7 @@ int
>> sigaddset (sigset_t *set, int signo)
>> {
>> if (set == NULL || signo <= 0 || signo >= NSIG
>> - || __is_internal_signal (signo))
>> + || is_internal_signal (signo))
> 
> OK. Function was renamed.
> 
>> {
>> __set_errno (EINVAL);
>> return -1;
>> diff --git a/signal/sigdelset.c b/signal/sigdelset.c
>> index 81bb9a908a..2c973c9b84 100644
>> --- a/signal/sigdelset.c
>> +++ b/signal/sigdelset.c
>> @@ -25,7 +25,7 @@ int
>> sigdelset (sigset_t *set, int signo)
>> {
>> if (set == NULL || signo <= 0 || signo >= NSIG
>> - || __is_internal_signal (signo))
>> + || is_internal_signal (signo))
> 
> OK. Function was renamed.
> 
>> {
>> __set_errno (EINVAL);
>> return -1;
>> diff --git a/signal/sigfillset.c b/signal/sigfillset.c
>> index b52ef06aa0..1d11ae4fec 100644
>> --- a/signal/sigfillset.c
>> +++ b/signal/sigfillset.c
>> @@ -31,7 +31,7 @@ sigfillset (sigset_t *set)
>> }
>> 
>> __sigfillset (set);
>> - __clear_internal_signals (set);
>> + clear_internal_signals (set);
> 
> OK. Function was renamed.
> 
>> return 0;
>> }
>> libc_hidden_def (sigfillset)
>> diff --git a/stdlib/abort.c b/stdlib/abort.c
>> index bcf72f9356..9c1065af0e 100644
>> --- a/stdlib/abort.c
>> +++ b/stdlib/abort.c
>> @@ -21,7 +21,7 @@
>> #include <stdlib.h>
>> #include <string.h>
>> #include <unistd.h>
>> -#include <sigsetops.h>
>> +#include <internal-signals.h>
> 
> OK. We will be operating on internal_sigset_t.
> 
>> 
>> /* Try to get a machine dependent instruction which will make the
>> program crash. This is used in case everything else fails. */
>> @@ -48,7 +48,6 @@ void
>> abort (void)
>> {
>> struct sigaction act;
>> - sigset_t sigs;
> 
> OK. Declared later.
> 
>> 
>> /* First acquire the lock. */
>> __libc_lock_lock_recursive (lock);
>> @@ -59,9 +58,10 @@ abort (void)
>> if (stage == 0)
>> {
>> ++stage;
>> - __sigemptyset (&sigs);
>> - __sigaddset (&sigs, SIGABRT);
>> - __sigprocmask (SIG_UNBLOCK, &sigs, 0);
>> + internal_sigset_t sigs;
>> + internal_sigemptyset (&sigs);
>> + internal_sigaddset (&sigs, SIGABRT);
>> + internal_sigprocmask (SIG_UNBLOCK, &sigs, NULL);
>> }
> 
> OK. Use new type and functions.
> 
>> 
>> /* Send signal which possibly calls a user handler. */
> 
>> diff --git a/sysdeps/posix/signal.c b/sysdeps/posix/signal.c
>> index 8f17b4278d..88c3757126 100644
>> --- a/sysdeps/posix/signal.c
>> +++ b/sysdeps/posix/signal.c
>> @@ -32,7 +32,7 @@ __bsd_signal (int sig, __sighandler_t handler)
>> 
>> /* Check signal extents to protect __sigismember. */
>> if (handler == SIG_ERR || sig < 1 || sig >= NSIG
>> - || __is_internal_signal (sig))
>> + || is_internal_signal (sig))
> 
> OK.
> 
>> {
>> __set_errno (EINVAL);
>> return SIG_ERR;
>> diff --git a/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c b/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
>> index a59ad78036..a53ae79965 100644
>> --- a/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
>> +++ b/sysdeps/unix/sysv/linux/ia64/unwind_longjmp.c
>> @@ -34,7 +34,7 @@ __libc_unwind_longjmp (sigjmp_buf env, int val)
>> 
>> if (env[0].__mask_was_saved)
>> /* Restore the saved signal mask. */
>> - __libc_signal_restore_set (&env[0].__saved_mask);
>> + __sigprocmask (SIG_SETMASK, &env[0].__saved_mask, NULL);
> 
> OK. internal_signal_restore_set operates on internal_sigset_t, but
> here we have a sigset_t. __saved_mask is a sigset_t, so we cannot use
> it here. Instead, we directly call sigprocmask like we did in
> __libc_signal_restore_set.
> 
>> 
>> /* Call the machine-dependent function to restore machine state. */
>> __sigstack_longjmp (env[0].__jmpbuf, val ?: 1);
> 
>> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
>> index d703485e3f..75f5c06e32 100644
>> --- a/sysdeps/unix/sysv/linux/spawni.c
>> +++ b/sysdeps/unix/sysv/linux/spawni.c
>> @@ -57,7 +57,7 @@
>> 
>> struct posix_spawn_args
>> {
>> - sigset_t oldmask;
>> + internal_sigset_t oldmask;
> 
> OK.
> 
>> const char *file;
>> int (*exec) (const char *, char *const *, char *const *);
>> const posix_spawn_file_actions_t *fa;
>> @@ -124,7 +124,7 @@ __spawni_child (void *arguments)
>> }
>> else if (__sigismember (&hset, sig))
>> {
>> - if (__is_internal_signal (sig))
>> + if (is_internal_signal (sig))
> 
> OK.
> 
>> sa.sa_handler = SIG_IGN;
>> else
>> {
>> @@ -284,8 +284,10 @@ __spawni_child (void *arguments)
>> 
>> /* Set the initial signal mask of the child if POSIX_SPAWN_SETSIGMASK
>> is set, otherwise restore the previous one. */
>> - __sigprocmask (SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
>> - ? &attr->__ss : &args->oldmask, 0);
>> + if (attr->__flags & POSIX_SPAWN_SETSIGMASK)
>> + __sigprocmask (SIG_SETMASK, &attr->__ss, NULL);
>> + else
>> + internal_sigprocmask (SIG_SETMASK, &args->oldmask, NULL);
> 
> OK. One is a sigset_t and the other is an internal_sigset_t, so we
> write this differently now. It's also more readable than the "?:"
> version.
> 
>> 
>> args->exec (args->file, args->argv, args->envp);
>> 
>> @@ -368,7 +370,7 @@ __spawnix (pid_t * pid, const char *file,
>> args.envp = envp;
>> args.xflags = xflags;
>> 
>> - __libc_signal_block_all (&args.oldmask);
>> + internal_signal_block_all (&args.oldmask);
> 
> OK.
> 
>> 
>> /* The clone flags used will create a new child that will run in the same
>> memory space (CLONE_VM) and the execution of calling thread will be
>> @@ -416,7 +418,7 @@ __spawnix (pid_t * pid, const char *file,
>> if ((ec == 0) && (pid != NULL))
>> *pid = new_pid;
>> 
>> - __libc_signal_restore_set (&args.oldmask);
>> + internal_signal_restore_set (&args.oldmask);
> 
> OK.
> 
>> 
>> __pthread_setcancelstate (state, NULL);
>> 
>> diff --git a/sysdeps/unix/sysv/linux/timer_routines.c b/sysdeps/unix/sysv/linux/timer_routines.c
>> index 8f0a2f635d..fc3deb6823 100644
>> --- a/sysdeps/unix/sysv/linux/timer_routines.c
>> +++ b/sysdeps/unix/sysv/linux/timer_routines.c
>> @@ -41,7 +41,7 @@ struct thread_start_data
>> static void *
>> timer_sigev_thread (void *arg)
>> {
>> - __libc_signal_unblock_sigtimer (NULL);
>> + signal_unblock_sigtimer (NULL);
> 
> OK.
> 
>> 
>> struct thread_start_data *td = (struct thread_start_data *) arg;
>> void (*thrfunc) (sigval_t) = td->thrfunc;
>> --
>> 2.34.1