hurd: Add _read.

* include/gnu/hurd.h (fd_read): Declare.
* include/gnu/syscall.h (SYS__io_read): New value.
* lib/gnu/_read.c: New file.
* lib/gnu/fd-read.c: New file.
* lib/gnu/io-read.c: New file.
* build-aux/configure-lib.sh (libc_SOURCES): Add _read sources.

build-aux/configure-lib.sh

@@ -149,6 +149,14 @@ lib/string/strcpy.c
 lib/string/strncmp.c
 "
 
+if test $mes_kernel = gnu; then
+    libc_SOURCES="$libc_SOURCES
+lib/gnu/_read.c
+lib/gnu/fd-read.c
+lib/gnu/io-read.c
+"
+fi
+
 if test $mes_kernel = linux; then
     libc_SOURCES="$libc_SOURCES
 lib/linux/access.c

include/gnu/hurd.h

@@ -61,5 +61,6 @@ extern struct hurd_startup_data _hurd_startup_data;
 
 mach_port_t fd_get (int filedes);
 error_t fd_write (mach_port_t port, void const *buffer, size_t *size, loff_t offset);
+error_t fd_read (mach_port_t port, void *buffer, size_t *size, loff_t offset);
 
 #endif // __MES_GNU_HURD_H

include/gnu/syscall.h

@@ -42,6 +42,7 @@ enum
 enum
   {
    SYS__io_write = 21000,
+   SYS__io_read,
   };
 
 // hurd/process.defs
@@ -78,6 +79,13 @@ struct mach_msg_2
   mach_msg_type_t type_two; int two;
 };
 
+struct mach_msg_loff_int
+{
+  mach_msg_header_t header;
+  mach_msg_type_t type_one; loff_t one;
+  mach_msg_type_t type_two; int two;
+};
+
 struct mach_msg_startup_info
 {
   mach_msg_header_t header;
@@ -123,5 +131,6 @@ kern_return_t __exec_startup_get_data (mach_port_t bootstrap, struct hurd_startu
 
 // io.c
 kern_return_t __io_write (io_t io_object, data_t data, mach_msg_type_number_t size, loff_t offset, vm_size_t *wrote);
+kern_return_t __io_read (io_t io, data_t *data, mach_msg_type_number_t *read, loff_t offset, vm_size_t size);
 
 #endif // __MES_GNU_SYSCALL_H

lib/gnu/_read.c

@@ -0,0 +1,34 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gnu/hurd.h>
+#include <gnu/hurd-types.h>
+#include <gnu/syscall.h>
+#include <mach/mach-init.h>
+
+ssize_t
+_read (int filedes, void *buffer, size_t size)
+{
+  mach_port_t p = fd_get (filedes);
+  error_t e = fd_read (p, buffer, &size, -1);
+  if (!e)
+    return size;
+  return -1;
+}

lib/gnu/fd-read.c

@@ -0,0 +1,40 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** Commentary:
+    Inspired by implementation in GNU C Library:
+    _hurd_fd_read
+    Copyright (C) 1993-2016 Free Software Foundation, Inc.
+ */
+
+#include <gnu/hurd.h>
+#include <gnu/syscall.h>
+#include <string.h>
+#include <errno.h>
+
+error_t
+fd_read (mach_port_t port, void *buffer, size_t *read, loff_t offset)
+{
+  char *data;
+  error_t e = __io_read (port, &data, read, offset, *read);
+  if (!e)
+    memcpy (buffer, data, *read);
+  return e;
+}

lib/gnu/io-read.c

@@ -0,0 +1,60 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gnu/syscall.h>
+
+struct mach_msg_int_pointer
+{
+  mach_msg_header_t header;
+  mach_msg_type_t type_one; int one;
+  mach_msg_type_long_t type_two; union {char *two; char pointer[2048];};
+};
+
+kern_return_t
+__io_read (io_t io, data_t *data, mach_msg_type_number_t *read, loff_t offset, vm_size_t size)
+{
+  union message
+  {
+    struct mach_msg_loff_int request;
+    struct mach_msg_int_pointer reply;
+  };
+  union message message = {0};
+  message.request.header.msgh_size = sizeof (message.request);
+  message.request.type_one = mach_msg_type_int64;
+  message.request.one = offset;
+  message.request.type_two = mach_msg_type_int32;
+  message.request.two = size;
+
+  kern_return_t result = __syscall_put (io, SYS__io_read,
+                                        &message.request.header,
+                                        sizeof (message.reply));
+
+  if (result == KERN_SUCCESS)
+    {
+      *read = message.reply.type_two.msgtl_number;
+      *data = message.reply.pointer;
+    }
+  else
+    {
+      *read = 0;
+      *data = 0;
+    }
+  return result;
+}