Comtrol eCos - Manual (Page 436)

Chapter 29. Writing a New Filesystem
static int ramfs_fo_dirread (struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio);
static int ramfs_fo_dirlseek (struct CYG_FILE_TAG *fp, off_t *pos, int whence );
We define all of the fstab entries and all of the file IO operations. We also define alternatives for the fo_read and
fo_lseek file IO operations.
We can now define the filesystem table entry. There is a macro, FSTAB_ENTRY to do this:
//==========================================================================
// Filesystem table entries
// -------------------------------------------------------------------------
// Fstab entry.
// This defines the entry in the filesystem table.
// For simplicity we use _FILESYSTEM synchronization for all accesses since
// we should never block in any filesystem operations.
FSTAB_ENTRY( ramfs_fste, "ramfs", 0,
CYG_SYNCMODE_FILE_FILESYSTEM|CYG_SYNCMODE_IO_FILESYSTEM,
ramfs_mount,
ramfs_umount,
ramfs_open,
ramfs_unlink,
ramfs_mkdir,
ramfs_rmdir,
ramfs_rename,
ramfs_link,
ramfs_opendir,
ramfs_chdir,
ramfs_stat,
ramfs_getinfo,
ramfs_setinfo);
The first argument to this macro gives the fstab entry a name, the remainder are initializers for the field of the
structure.
We must also define the file operations table that is installed in all open file table entries:
// -------------------------------------------------------------------------
// File operations.
// This set of file operations are used for normal open files.
static cyg_fileops ramfs_fileops =
{
ramfs_fo_read,
ramfs_fo_write,
ramfs_fo_lseek,
ramfs_fo_ioctl,
cyg_fileio_seltrue,
ramfs_fo_fsync,
ramfs_fo_close,
ramfs_fo_fstat,
ramfs_fo_getinfo,
ramfs_fo_setinfo
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