hurd: Make write and pwrite64 cancellation points

and add _nocancel variants.

* sysdeps/mach/hurd/write.c (__libc_write): Call __write_nocancel
surrounded by enabling async cancel, to replace implementation moved
to...
* sysdeps/mach/hurd/write_nocancel.c (__write_nocancel): ... here.
* sysdeps/mach/hurd/pwrite64.c (__libc_pwrite64): Call
__pwrite64_nocancel surrounded by enabling async cancel, to replace
implementation moved to...
* sysdeps/mach/hurd/pwrite64_nocancel.c (__pwrite64_nocancel): ... here.
* sysdeps/mach/hurd/Makefile (sysdep_routines): Add write_nocancel and
pwrite64_nocancel.
* sysdeps/mach/hurd/not-cancel.h (__write_nocancel,
__pwrite64_nocancel): Replace macros with prototypes with a hidden proto on
libc.

* sysdeps/mach/hurd/dl-sysdep.c (__write_nocancel): New alias, check
that it is not hidden.
* sysdeps/mach/hurd/Versions (libc.GLIBC_PRIVATE): Add __write_nocancel.
(ld.GLIBC_PRIVATE): Add __write_nocancel.
* sysdeps/mach/hurd/i386/localplt.data (__write_nocancel): Add
reference.

sysdeps/mach/hurd/Makefile

@@ -197,7 +197,7 @@ endif
 
 ifeq (io, $(subdir))
 sysdep_routines += f_setlk close_nocancel_nostatus read_nocancel \
-		   pread64_nocancel
+		   pread64_nocancel write_nocancel pwrite64_nocancel
 endif
 
 ifeq ($(subdir),sunrpc)

sysdeps/mach/hurd/Versions

@@ -11,6 +11,7 @@ libc {
     # Functions shared with the dynamic linker
     __access; __access_noerrno; __libc_read; __libc_write; __libc_lseek64;
     __read_nocancel; __pread64_nocancel;
+    __write_nocancel;
     __libc_lock_self0; __getcwd;
 
     _dl_init_first;
@@ -51,6 +52,7 @@ ld {
     # functions that must be shared with libc
     __access; __access_noerrno; __libc_read; __libc_write; __libc_lseek64;
     __read_nocancel; __pread64_nocancel;
+    __write_nocancel;
     __libc_lock_self0; __getcwd;
   }
 }

sysdeps/mach/hurd/dl-sysdep.c

@@ -396,6 +396,7 @@ libc_hidden_weak (__read)
 weak_alias (__read, __read_nocancel)
 
 check_no_hidden(__write);
+check_no_hidden(__write_nocancel);
 __ssize_t weak_function
 __write (int fd, const void *buf, size_t nbytes)
 {
@@ -411,6 +412,7 @@ __write (int fd, const void *buf, size_t nbytes)
   return nwrote;
 }
 libc_hidden_weak (__write)
+  weak_alias (__write, __write_nocancel)
 
 /* This is only used for printing messages (see dl-misc.c).  */
 check_no_hidden(__writev);

sysdeps/mach/hurd/i386/localplt.data

@@ -23,7 +23,8 @@ ld.so: __read ?
 ld.so: __read_nocancel
 ld.so: __pread64
 ld.so: __pread64_nocancel
-ld.so: __write
+ld.so: __write ?
+ld.so: __write_nocancel
 ld.so: __writev
 ld.so: __libc_lseek64
 ld.so: __mmap

sysdeps/mach/hurd/not-cancel.h

@@ -48,8 +48,12 @@ __typeof (__read) __read_nocancel;
 /* Non cancellable pread syscall (LFS version).  */
 __typeof (__pread64) __pread64_nocancel;
 
-#define __write_nocancel(fd, buf, n) \
-  __write (fd, buf, n)
+/* Non cancellable write syscall.  */
+__typeof (__write) __write_nocancel;
+
+/* Non cancellable pwrite syscall (LFS version).  */
+__typeof (__pwrite64) __pwrite64_nocancel;
+
 #define __writev_nocancel_nostatus(fd, iov, n) \
   (void) __writev (fd, iov, n)
 # define __waitpid_nocancel(pid, stat_loc, options) \
@@ -60,6 +64,8 @@ __typeof (__pread64) __pread64_nocancel;
 #if IS_IN (libc)
 hidden_proto (__read_nocancel)
 hidden_proto (__pread64_nocancel)
+hidden_proto (__write_nocancel)
+hidden_proto (__pwrite64_nocancel)
 hidden_proto (__close_nocancel_nostatus)
 #endif
 

sysdeps/mach/hurd/pwrite64.c

@@ -17,19 +17,17 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <unistd.h>
-#include <hurd/fd.h>
+#include <sysdep-cancel.h>
+#include <not-cancel.h>
 
 ssize_t
 __libc_pwrite64 (int fd, const void *buf, size_t nbytes, off64_t offset)
 {
-  error_t err;
-  if (offset < 0)
-    err = EINVAL;
-  else
-    err = HURD_FD_USE (fd, _hurd_fd_write (descriptor, buf, &nbytes, offset));
-  return err ? __hurd_dfail (fd, err) : nbytes;
+  ssize_t ret;
+  int cancel_oldtype = LIBC_CANCEL_ASYNC();
+  ret = __pwrite64_nocancel (fd, buf, nbytes, offset);
+  LIBC_CANCEL_RESET (cancel_oldtype);
+  return ret;
 }
 
 #ifndef __libc_pwrite64

sysdeps/mach/hurd/pwrite64_nocancel.c

@@ -0,0 +1,35 @@
+/* Write block to given position in file without changing file pointer.
+   Hurd version.
+   Copyright (C) 2001-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <unistd.h>
+#include <hurd/fd.h>
+#include <not-cancel.h>
+
+ssize_t
+__pwrite64_nocancel (int fd, const void *buf, size_t nbytes, off64_t offset)
+{
+  error_t err;
+  if (offset < 0)
+    err = EINVAL;
+  else
+    err = HURD_FD_USE (fd, _hurd_fd_write (descriptor, buf, &nbytes, offset));
+  return err ? __hurd_dfail (fd, err) : nbytes;
+}
+libc_hidden_weak (__pwrite64_nocancel)

sysdeps/mach/hurd/write.c

@@ -15,16 +15,17 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <unistd.h>
-#include <hurd/fd.h>
+#include <sysdep-cancel.h>
+#include <not-cancel.h>
 
 ssize_t
 __libc_write (int fd, const void *buf, size_t nbytes)
 {
-  error_t err = HURD_FD_USE (fd, _hurd_fd_write (descriptor,
-						 buf, &nbytes, -1));
-  return err ? __hurd_dfail (fd, err) : nbytes;
+  ssize_t ret;
+  int cancel_oldtype = LIBC_CANCEL_ASYNC();
+  ret = __write_nocancel (fd, buf, nbytes);
+  LIBC_CANCEL_RESET (cancel_oldtype);
+  return ret;
 }
 libc_hidden_def (__libc_write)
 weak_alias (__libc_write, __write)

sysdeps/mach/hurd/write_nocancel.c

@@ -0,0 +1,30 @@
+/* Copyright (C) 1991-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <unistd.h>
+#include <hurd/fd.h>
+#include <not-cancel.h>
+
+ssize_t
+__write_nocancel (int fd, const void *buf, size_t nbytes)
+{
+  error_t err = HURD_FD_USE (fd, _hurd_fd_write (descriptor,
+						 buf, &nbytes, -1));
+  return err ? __hurd_dfail (fd, err) : nbytes;
+}
+libc_hidden_weak (__write_nocancel)