compiler/clib/fcntl.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <proto/dos.h>
   7
   8 #include <errno.h>
   9 #include <stdarg.h>
  10 #include <unistd.h>
  11
  12 #include "__errno.h"
  13 #include "__fdesc.h"
  14
  15 /*****************************************************************************
  16
  17     NAME */
  18 #include <fcntl.h>
  19
  20         int fcntl(
  21
  22 /*  SYNOPSIS */
  23         int fd,
  24         int cmd,
  25         ...)
  26
  27 /*  FUNCTION
  28         Perform operation specified in cmd on the file descriptor fd.
  29         Some operations require additional arguments, in this case they
  30         follow the cmd argument. The following operations are available:
  31
  32         F_DUPFD (int)  - Duplicate file descriptor fd as the lowest numbered
  33                          file descriptor greater or equal to the operation
  34                          argument.
  35
  36         F_GETFD (void) - Read the file descriptor flags
  37
  38         F_SETFD (int)  - Set the file descriptor flags to value given in
  39                          the operation argument
  40
  41         F_GETFL (void) - Read the file status flags
  42
  43         F_SETFL (int)  - Set the file status flags to value given in the
  44                          operation argument.
  45
  46         File descriptor flags are zero or more ORed constants:
  47
  48         FD_CLOEXEC - File descriptor will be closed during execve()
  49
  50         File descriptor flags are not copied during duplication of file
  51         descriptors.
  52
  53         File status flags are the flags given as mode parameter to open()
  54         function call. You can change only a few file status flags in opened
  55         file descriptor: O_NONBLOCK, O_APPEND and O_ASYNC. Any other file
  56         status flags passed in F_SETFL argument will be ignored.
  57
  58         All duplicated file descriptors share the same set of file status
  59         flags.
  60
  61     INPUTS
  62         fd - File descriptor to perform operation on.
  63         cmd - Operation specifier.
  64         ... - Operation arguments.
  65
  66     RESULT
  67         The return value of the function depends on the performed operation:
  68
  69         F_DUPFD  - New duplicated file descriptor
  70
  71         F_GETFD  - File descriptor flags
  72
  73         F_SETFD  - 0
  74
  75         F_GETFL  - File status flags
  76
  77         F_SETFL  - 0 on success, -1 on error. In case of error a global errno
  78                    variable is set.
  79
  80     NOTES
  81
  82     EXAMPLE
  83
  84     BUGS
  85
  86     SEE ALSO
  87         open()
  88
  89     INTERNALS
  90
  91 ******************************************************************************/
  92 {
  93     fdesc *desc = __getfdesc(fd);
  94
  95     if (!desc)
  96     {
  97         errno = EBADF;
  98         return -1;
  99     }
 100
 101     switch (cmd)
 102     {
 103         case F_DUPFD:
 104         {
 105             va_list ap;
 106             int     arg;
 107
 108             va_start(ap, cmd);
 109             arg = va_arg(ap, int);
 110             va_end(ap);
 111
 112             /*
 113                 FIXME: FD_CLOEXEC must be off on the copy, once this flag
 114                        is supported (related to F_GETFD and F_SETFD).
 115             */
 116
 117             return dup2(fd, __getfirstfd(arg));
 118         }
 119         case F_GETFD:
 120             return desc->fdflags;
 121
 122         case F_SETFD:
 123         {
 124             va_list ap;
 125             int     arg;
 126
 127             va_start(ap, cmd);
 128             arg = va_arg(ap, int);
 129             va_end(ap);
 130
 131             desc->fdflags = arg;
 132             return 0;
 133         }
 134
 135         case F_GETFL:
 136             return desc->fcb->flags & (O_NONBLOCK|O_APPEND|O_ASYNC);
 137
 138         case F_SETFL:
 139         {
 140             va_list ap;
 141             int     arg;
 142             int     oldmode = __oflags2amode(desc->fcb->flags & ~(O_NONBLOCK|O_APPEND|O_ASYNC));
 143
 144             va_start(ap, cmd);
 145             arg = va_arg(ap, int);
 146             va_end(ap);
 147
 148             arg &= (O_NONBLOCK|O_APPEND|O_ASYNC);
 149
 150             if (ChangeMode(CHANGE_FH, desc->fcb->fh, oldmode | __oflags2amode(arg)) == DOSTRUE)
 151             {
 152                 desc->fcb->flags &= ~(O_NONBLOCK|O_APPEND|O_ASYNC);
 153                 desc->fcb->flags |= arg;
 154                 return 0;
 155             }
 156
 157             errno = IoErr2errno(IoErr());
 158             return -1;
 159         }
 160
 161         default:
 162             errno = EINVAL;
 163             return -1;
 164     }
 165 }