1: /* Get a host configuration item kept as the whole contents of a file.
    2:    Copyright (C) 1996,97,99,2000,2001 Free Software Foundation, Inc.
    3:    This file is part of the GNU C Library.
    4: 
    5:    The GNU C Library is free software; you can redistribute it and/or
    6:    modify it under the terms of the GNU Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the License, or (at your option) any later version.
    9: 
   10:    The GNU C Library is distributed in the hope that it will be useful,
   11:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   13:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.  */
   19: 
   20: #include <fcntl.h>
   21: #include <hurd.h>
   22: #include <hurd/lookup.h>
   23: #include "hurdhost.h"
   24: #include <string.h>
   25: 
   26: ssize_t
   27: _hurd_get_host_config (const char *item, char *buf, size_t buflen)
   28: {
   29:   error_t err;
   30:   char *data;
   31:   mach_msg_type_number_t nread, more;
   32:   file_t config;
   33: 
   34:   err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0,
   35:                                  item, O_RDONLY, 0, &config);
   36:   switch (err)
   37:     {
   38:     case 0:                     /* Success; read file contents below.  */
   39:       break;
   40: 
   41:     case ENOENT:                /* ? Others?  All errors? */
   42:       /* The file does not exist, so no value has been set.  Rather than
   43:          causing gethostname et al to fail with ENOENT, give an empty value
   44:          as other systems do before sethostname has been called.  */
   45:       if (buflen != 0)
   46:         *buf = '\0';
   47:       return 0;
   48: 
   49:     default:
   50:       return __hurd_fail (err);
   51:     }
   52: 
   53:   data = buf;
   54:   err = __io_read (config, &data, &nread, -1, buflen);
   55:   if (! err)
   56:     /* Check if there is more in the file we didn't read.  */
   57:     err = __io_readable (config, &more);
   58:   __mach_port_deallocate (__mach_task_self (), config);
   59:   if (err)
   60:     return __hurd_fail (err);
   61:   if (data != buf)
   62:     {
   63:       memcpy (buf, data, nread);
   64:       __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
   65:     }
   66: 
   67:   /* If the file is empty, give an empty value.  */
   68:   if (nread == 0)
   69:     {
   70:       if (buflen != 0)
   71:         *buf = '\0';
   72:       return 0;
   73:     }
   74: 
   75:   /* Remove newlines in case someone wrote the file by hand.  */
   76:   while (nread > 0 && buf[nread - 1] == '\n')
   77:     buf[--nread] = '\0';
   78: 
   79:   /* Null-terminate the result if there is enough space.  */
   80:   if (nread < buflen)
   81:     buf[nread] = '\0';
   82:   else
   83:     if (buf[nread - 1] != '\0')
   84:       more = 1;
   85: 
   86:   if (more)
   87:     /* If we didn't read the whole file, tell the caller to use a bigger
   88:        buffer next time.  */
   89:     return __hurd_fail (ENAMETOOLONG);
   90: 
   91:   return nread;
   92: }