hurd: Make read and pread64 cancellable

and add _nocancel variants.

* sysdeps/mach/hurd/pread64.c (__libc_pread64):  Call __pread64_nocancel
surrounded by enabling async cancel, to replace implementation moved to...
* sysdeps/mach/hurd/pread64_nocancel.c (__pread64_nocancel): ... here.
* sysdeps/mach/hurd/read.c (__libc_read): Call __read_nocancel surrounded by
enabling async cancel, to replace implementation moved to...
* sysdeps/mach/hurd/read_nocancel.c (__read_nocancel): ... here.
* sysdeps/mach/hurd/Makefile (sysdep_routines): Add read_nocancel and
pread64_nocancel.
* sysdeps/mach/hurd/not-cancel.h (__read_nocancel, __pread64_nocancel):
Replace macros with prototypes with a hidden proto on libc.

* sysdeps/mach/hurd/dl-sysdep.c: Include <not-cancel.h>.
(__pread64_nocancel): New alias, check that it is not hidden.
(__read_nocancel): New alias, check that it is not hidden.

* sysdeps/mach/hurd/Versions (libc.GLIBC_PRIVATE): Add __read_nocancel and
__pread64_nocancel.
(ld.GLIBC_2.1): Add __pread64.
(ld.GLIBC_PRIVATE): Add __read_nocancel and __pread64_nocancel.
* sysdeps/mach/hurd/i386/ld.abilist (__pread64): Add symbol.
* sysdeps/mach/hurd/i386/localplt.data (__read_nocancel, __pread64,
__pread64_nocancel): Add references.

1 files changed, 35 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/pread64_nocancel.c b/sysdeps/mach/hurd/pread64_nocancel.c
new file mode 100644
index 0000000000..f6bc5e62b4
--- /dev/null
+++ b/sysdeps/mach/hurd/pread64_nocancel.c
@@ -0,0 +1,35 @@
+/* Read block from 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
+__pread64_nocancel (int fd, void *buf, size_t nbytes, off64_t offset)
+{
+  error_t err;
+  if (offset < 0)
+    err = EINVAL;
+  else
+    err = HURD_FD_USE (fd, _hurd_fd_read (descriptor, buf, &nbytes, offset));
+  return err ? __hurd_dfail (fd, err) : nbytes;
+}
+libc_hidden_weak (__pread64_nocancel)