minix/servers/vfs/const.h
Ben Gras 35a83eadc0 vfs: mmap support
. libc: add vfs_mmap, a way for vfs to initiate mmap()s.
	  This is a good special case to have as vfs is a slightly
	  different client from regular user processes. It doesn't do it
	  for itself, and has the dev & inode info already so the callback
	  to VFS for the lookup isn't necessary. So it has different info
	  to have to give to VM.
	. libc: also add minix_mmap64() that accepts a 64-bit offset, even
	  though our off_t is still 32 bit now.
	. to support mmap, we need to create new references to FD's (such
	  as an FD) so that the mmapped object can never be removed even if
	  all FD's are closed. To do that we conceptually dup the
	  filedescriptor into a new range that is only visible to the system.
	  So there are FDS_PER_PROCESS fd's, which is more than OPEN_MAX,
	  per process, and user processes can still use up to OPEN_MAX
	  FD's. mmap()ped objects then get extra reference in the invisible
	  range so user processes can't close them. The in-vfs fd_set is
	  of size FDS_PER_PROCESS.
	. On exec() time, try to mmap() in the executable if available.
	  (It is not yet available in this commit.)
	. To support mmap(), add do_vm_call that allows VM to lookup
	  (to ino+dev), do i/o from and close FD's on behalf of other
	  processes.
	. To make this possible, a few functions have 2 more arguments
	  to make the target process explicit (instead of the implicit
	  global fp) and to specify whether the request is from a user
	  process or the system (which implies whether FD's starting at
	  OPEN_MAX are valid). These are close_fd, common_open, actual_llseek,
	  actual_read_write_peek, get_fd and get_filp2.

Change-Id: I831551e45a6781c74313c450eb9c967a68505932
2013-05-18 16:10:47 +00:00

60 lines
2.2 KiB
C

#ifndef __VFS_CONST_H__
#define __VFS_CONST_H__
/* How many FD's must be reserved per process? OPEN_MAX are
* user-visible, SYSTEM_FDS_MAX are system-usable.
*/
#define SYSTEM_FDSTART OPEN_MAX /* How many user FD's */
#define SYSTEM_FDS_MAX OPEN_MAX /* How many system FD's */
#define FDS_PER_PROCESS (OPEN_MAX+SYSTEM_FDS_MAX) /* Total FD's */
/* Tables sizes */
#define NR_FILPS 1024 /* # slots in filp table */
#define NR_LOCKS 8 /* # slots in the file locking table */
#define NR_MNTS 16 /* # slots in mount table */
#define NR_VNODES 1024 /* # slots in vnode table */
#define NR_WTHREADS 8 /* # slots in worker thread table */
#define NR_NONEDEVS NR_MNTS /* # slots in nonedev bitmap */
/* Miscellaneous constants */
#define SU_UID ((uid_t) 0) /* super_user's uid_t */
#define SYS_UID ((uid_t) 0) /* uid_t for system processes and INIT */
#define SYS_GID ((gid_t) 0) /* gid_t for system processes and INIT */
#define FP_BLOCKED_ON_NONE 0 /* not blocked */
#define FP_BLOCKED_ON_PIPE 1 /* susp'd on pipe */
#define FP_BLOCKED_ON_LOCK 2 /* susp'd on lock */
#define FP_BLOCKED_ON_POPEN 3 /* susp'd on pipe open */
#define FP_BLOCKED_ON_SELECT 4 /* susp'd on select */
#define FP_BLOCKED_ON_DOPEN 5 /* susp'd on device open */
#define FP_BLOCKED_ON_OTHER 6 /* blocked on other process, check
fp_task to find out */
/* test if the process is blocked on something */
#define fp_is_blocked(fp) ((fp)->fp_blocked_on != FP_BLOCKED_ON_NONE)
/* test if reply is a driver reply */
#define IS_DRV_REPLY(x) (IS_DEV_RS(x) || IS_BDEV_RS(x) || (x) == TASK_REPLY)
#define DUP_MASK 0100 /* mask to distinguish dup2 from dup */
#define LOOK_UP 0 /* tells search_dir to lookup string */
#define ENTER 1 /* tells search_dir to make dir entry */
#define DELETE 2 /* tells search_dir to delete entry */
#define IS_EMPTY 3 /* tells search_dir to ret. OK or ENOTEMPTY */
#define SYMLOOP 16
#define LABEL_MAX 16 /* maximum label size (including '\0'). Should
* not be smaller than 16 or bigger than
* M3_LONG_STRING.
*/
/* Args to dev_io */
#define VFS_DEV_READ 2001
#define VFS_DEV_WRITE 2002
#define VFS_DEV_IOCTL 2005
#define VFS_DEV_SELECT 2006
#endif