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glibc  2.9
fd-read.c
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00001 /* Copyright (C) 1993,94,95,97,99,2002,2008 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <unistd.h>
00021 #include <hurd.h>
00022 #include <hurd/fd.h>
00023 #include <string.h>
00024 
00025 error_t
00026 _hurd_fd_read (struct hurd_fd *fd, void *buf, size_t *nbytes, loff_t offset)
00027 {
00028   error_t err;
00029   char *data;
00030   mach_msg_type_number_t nread;
00031 
00032   error_t readfd (io_t port)
00033     {
00034       return __io_read (port, &data, &nread, offset, *nbytes);
00035     }
00036 
00037   data = buf;
00038   nread = *nbytes;
00039   if (err = HURD_FD_PORT_USE (fd, _hurd_ctty_input (port, ctty, readfd)))
00040     return err;
00041 
00042   if (data != buf)
00043     {
00044       if (nread > *nbytes)  /* Sanity check for bogus server.  */
00045        {
00046          __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
00047          return EGRATUITOUS;
00048        }
00049       memcpy (buf, data, nread);
00050       __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
00051     }
00052 
00053   *nbytes = nread;
00054   return 0;
00055 }