compiler/clib/fcntl.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <proto/dos.h>
   7
   8 #include <fcntl.h>
   9 #include <errno.h>
  10 #include <stdarg.h>
  11
  12 #include "__errno.h"
  13 #include "__open.h"
  14
  15 /*****************************************************************************
  16
  17     NAME */
  18         int fcntl(
  19
  20 /*  SYNOPSIS */
  21         int fd,
  22         int cmd,
  23         ...)
  24
  25 /*  FUNCTION
  26         Perform operation specified in cmd on the file descriptor fd.
  27         Some operations require additional arguments, in this case they
  28         follow the cmd argument. The following operations are available:
  29
  30         F_DUPFD (int)  - Duplicate file descriptor fd as the lowest numbered
  31                          file descriptor greater or equal to the operation
  32                          argument.
  33
  34         F_GETFD (void) - Read the file descriptor flags
  35
  36         F_SETFD (int)  - Set the file descriptor flags to value given in
  37                          the operation argument
  38
  39         F_GETFL (void) - Read the file status flags
  40
  41         F_SETFL (int)  - Set the file status flags to value given in the
  42                          operation argument.
  43
  44         File descriptor flags are zero or more ORed constants:
  45
  46         FD_CLOEXEC - File descriptor will be closed during execve()
  47
  48         File descriptor flags are not copied during duplication of file
  49         descriptors.
  50
  51         File status flags are the flags given as mode parameter to open()
  52         function call. You can change only a few file status flags in opened
  53         file descriptor: O_NONBLOCK, O_APPEND and O_ASYNC. Any other file
  54         status flags passed in F_SETFL argument will be ignored.
  55
  56         All duplicated file descriptors share the same set of file status
  57         flags.
  58
  59     INPUTS
  60         fd - File descriptor to perform operation on.
  61         cmd - Operation specifier.
  62         ... - Operation arguments.
  63
  64     RESULT
  65         The return value of the function depends on the performed operation:
  66
  67         F_DUPFD  - New duplicated file descriptor
  68
  69         F_GETFD  - File descriptor flags
  70
  71         F_SETFD  - 0
  72
  73         F_GETFL  - File status flags
  74
  75         F_SETFL  - 0 on success, -1 on error. In case of error a global errno
  76                    variable is set.
  77
  78     NOTES
  79
  80     EXAMPLE
  81
  82     BUGS
  83
  84     SEE ALSO
  85         open()
  86
  87     INTERNALS
  88
  89 ******************************************************************************/
  90 {
  91     fdesc *desc = __getfdesc(fd);
  92
  93     if (!desc)
  94     {
  95         errno = EBADF;
  96         return -1;
  97     }
  98
  99     switch (cmd)
 100     {
 101         case F_DUPFD:
 102         {
 103             va_list ap;
 104             int     arg;
 105
 106             va_start(ap, cmd);
 107             arg = va_arg(ap, int);
 108             va_end(ap);
 109
 110             /*
 111                 FIXME: FD_CLOEXEC must be off on the copy, once this flag
 112                        is supported (related to F_GETFD and F_SETFD).
 113             */
 114
 115             return dup2(fd, __getfirstfd(arg));
 116         }
 117         case F_GETFD:
 118             return desc->fdflags;
 119
 120         case F_SETFD:
 121         {
 122             va_list ap;
 123             int     arg;
 124
 125             va_start(ap, cmd);
 126             arg = va_arg(ap, int);
 127             va_end(ap);
 128
 129             desc->fdflags = arg;
 130             return 0;
 131         }
 132
 133         case F_GETFL:
 134             return desc->fcb->flags & (O_NONBLOCK|O_APPEND|O_ASYNC);
 135
 136         case F_SETFL:
 137         {
 138             va_list ap;
 139             int     arg;
 140             int     oldmode = __oflags2amode(desc->fcb->flags & ~(O_NONBLOCK|O_APPEND|O_ASYNC));
 141
 142             va_start(ap, cmd);
 143             arg = va_arg(ap, int);
 144             va_end(ap);
 145
 146             arg &= (O_NONBLOCK|O_APPEND|O_ASYNC);
 147
 148             if (ChangeMode(CHANGE_FH, desc->fcb->fh, oldmode | __oflags2amode(arg)) == DOSTRUE)
 149             {
 150                 desc->fcb->flags &= ~(O_NONBLOCK|O_APPEND|O_ASYNC);
 151                 desc->fcb->flags |= arg;
 152                 return 0;
 153             }
 154
 155             errno = IoErr2errno(IoErr());
 156             return -1;
 157         }
 158
 159         default:
 160             errno = EINVAL;
 161             return -1;
 162     }
 163 }