hurd/fopenport.c

   1 /* Copyright (C) 1994-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <hurd.h>
  19 #include <stdio.h>
  20 #include <fcntl.h>
  21 #include <string.h>
  22
  23 /* Read up to N chars into BUF from COOKIE.
  24    Return how many chars were read, 0 for EOF or -1 for error.  */
  25 static ssize_t
  26 readio (void *cookie, char *buf, size_t n)
  27 {
  28   mach_msg_type_number_t nread;
  29   error_t err;
  30   char *bufp = buf;
  31   io_t io = (io_t) (uintptr_t) cookie;
  32
  33   nread = n;
  34   if (err = __io_read (io, &bufp, &nread, -1, n))
  35     return __hurd_fail (err);
  36
  37   if (bufp != buf)
  38     {
  39       memcpy (buf, bufp, nread);
  40       __vm_deallocate (__mach_task_self (),
  41                        (vm_address_t) bufp, (vm_size_t) nread);
  42     }
  43
  44   return nread;
  45 }
  46
  47 /* Write up to N chars from BUF to COOKIE.
  48    Return how many chars were written or -1 for error.  */
  49 static ssize_t
  50 writeio (void *cookie, const char *buf, size_t n)
  51 {
  52   vm_size_t wrote;
  53   error_t err;
  54   io_t io = (io_t) (uintptr_t) cookie;
  55
  56   if (err = __io_write (io, buf, n, -1, &wrote))
  57     return __hurd_fail (err);
  58
  59   return wrote;
  60 }
  61
  62 /* Move COOKIE's file position *POS bytes, according to WHENCE.
  63    The current file position is stored in *POS.
  64    Returns zero if successful, nonzero if not.  */
  65 static int
  66 seekio (void *cookie,
  67         off64_t *pos,
  68         int whence)
  69 {
  70   io_t io = (io_t) (uintptr_t) cookie;
  71   error_t err = __io_seek (io, *pos, whence, pos);
  72   return err ? __hurd_fail (err) : 0;
  73 }
  74
  75 /* Close the file associated with COOKIE.
  76    Return 0 for success or -1 for failure.  */
  77 static int
  78 closeio (void *cookie)
  79 {
  80   io_t io = (io_t) (uintptr_t) cookie;
  81   error_t error = __mach_port_deallocate (__mach_task_self (),
  82                                           io);
  83   if (error)
  84     return __hurd_fail (error);
  85   return 0;
  86 }
  87
  88 #include "../libio/libioP.h"
  89 #define fopencookie _IO_fopencookie
  90 static const cookie_io_functions_t funcsio =
  91 { readio, writeio, seekio, closeio };
  92 \f
  93
  94 /* Open a stream on PORT.  MODE is as for fopen.  */
  95
  96 FILE *
  97 __fopenport (mach_port_t port, const char *mode)
  98 {
  99   int pflags;
 100   int needflags;
 101   error_t err;
 102
 103   const char *m = mode;
 104
 105   switch (*m++)
 106     {
 107     case 'r':
 108       needflags = O_READ;
 109       break;
 110     case 'w':
 111       needflags = O_WRITE;
 112       break;
 113     case 'a':
 114       needflags = O_WRITE|O_APPEND;
 115       break;
 116     default:
 117       return NULL;
 118   }
 119   if (m[0] == '+' || (m[0] == 'b' && m[1] == '+'))
 120     needflags |= O_RDWR;
 121
 122   /* Verify the PORT is valid allows the access MODE specifies.  */
 123
 124   if (err = __io_get_openmodes (port, &pflags))
 125     return __hurd_fail (err), NULL;
 126
 127   /* Check the access mode.  */
 128   if ((pflags & needflags) != needflags)
 129     return __hurd_fail (EBADF), NULL;
 130
 131   return fopencookie ((void *) (uintptr_t) port,
 132                       mode, funcsio);
 133 }
 134 weak_alias (__fopenport, fopenport)