diff options
Diffstat (limited to 'kernel/fs/vnode_specials.c')
| -rw-r--r-- | kernel/fs/vnode_specials.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/kernel/fs/vnode_specials.c b/kernel/fs/vnode_specials.c new file mode 100644 index 0000000..a6c38a3 --- /dev/null +++ b/kernel/fs/vnode_specials.c @@ -0,0 +1,176 @@ +#include <errno.h> +#include <fs/stat.h> +#include <fs/vfs.h> +#include <fs/vnode.h> +#include <util/debug.h> + +static long special_file_stat(vnode_t *file, stat_t *ss); + +static ssize_t chardev_file_read(vnode_t *file, size_t pos, void *buf, + size_t count); + +static ssize_t chardev_file_write(vnode_t *file, size_t pos, const void *buf, + size_t count); + +static long chardev_file_mmap(vnode_t *file, mobj_t **ret); + +static long chardev_file_fill_pframe(vnode_t *file, pframe_t *pf); + +static long chardev_file_flush_pframe(vnode_t *file, pframe_t *pf); + +static vnode_ops_t chardev_spec_vops = { + .read = chardev_file_read, + .write = chardev_file_write, + .mmap = chardev_file_mmap, + .mknod = NULL, + .lookup = NULL, + .link = NULL, + .unlink = NULL, + .mkdir = NULL, + .rmdir = NULL, + .readdir = NULL, + .stat = special_file_stat, + .get_pframe = NULL, + .fill_pframe = chardev_file_fill_pframe, + .flush_pframe = chardev_file_flush_pframe, +}; + +static ssize_t blockdev_file_read(vnode_t *file, size_t pos, void *buf, + size_t count); + +static ssize_t blockdev_file_write(vnode_t *file, size_t pos, const void *buf, + size_t count); + +static long blockdev_file_mmap(vnode_t *file, mobj_t **ret); + +static long blockdev_file_fill_pframe(vnode_t *file, pframe_t *pf); + +static long blockdev_file_flush_pframe(vnode_t *file, pframe_t *pf); + +static vnode_ops_t blockdev_spec_vops = { + .read = blockdev_file_read, + .write = blockdev_file_write, + .mmap = blockdev_file_mmap, + .mknod = NULL, + .lookup = NULL, + .link = NULL, + .unlink = NULL, + .mkdir = NULL, + .rmdir = NULL, + .readdir = NULL, + .stat = special_file_stat, + .get_pframe = NULL, + .fill_pframe = blockdev_file_fill_pframe, + .flush_pframe = blockdev_file_flush_pframe, +}; + +void init_special_vnode(vnode_t *vn) +{ + if (S_ISCHR(vn->vn_mode)) + { + vn->vn_ops = &chardev_spec_vops; + vn->vn_dev.chardev = chardev_lookup(vn->vn_devid); + } + else + { + KASSERT(S_ISBLK(vn->vn_mode)); + vn->vn_ops = &blockdev_spec_vops; + vn->vn_dev.blockdev = blockdev_lookup(vn->vn_devid); + } +} + +static long special_file_stat(vnode_t *file, stat_t *ss) +{ + KASSERT(file->vn_fs->fs_root->vn_ops->stat != NULL); + // call the containing file system's stat routine + return file->vn_fs->fs_root->vn_ops->stat(file, ss); +} + +/* + * Make a read by deferring to the underlying chardev and its read operation. + * + * Returns what the chardev's read returned. + * + * Hint: Watch out! chardev_file_read and chardev_file_write are indirectly + * called in do_read and do_write, respectively, as the read/write ops for + * chardev-type vnodes. This means that the vnode file should be locked + * upon entry to this function. + * + * However, tty_read and tty_write, the read/write ops for the tty chardev, + * are potentially blocking. To avoid deadlock, you should unlock the file + * before calling the chardev's read, and lock it again after. If you fail + * to do this, a shell reading from /dev/tty0 for instance, will block all + * access to the /dev/tty0 vnode. This means that if someone runs `ls /dev/`, + * while a shell is reading from `/dev/tty0`, the `ls` call will hang. + * + * Also, if a vnode represents a chardev, you can access the chardev using + * vnode->vn_dev.chardev. + * + */ +static ssize_t chardev_file_read(vnode_t *file, size_t pos, void *buf, + size_t count) +{ + NOT_YET_IMPLEMENTED("VFS: ***none***"); + return 0; +} + +/* + * Make a write by deferring to the underlying chardev and its write operation. + * + * Return what the chardev's write returned. + * + * See the comments from chardev_file_read above for hints. + * + */ +static long chardev_file_write(vnode_t *file, size_t pos, const void *buf, + size_t count) +{ + NOT_YET_IMPLEMENTED("VFS: ***none***"); + return 0; +} + +/* + * For this and the following chardev functions, simply defer to the underlying + * chardev's corresponding operations. + */ +static long chardev_file_mmap(vnode_t *file, mobj_t **ret) +{ + NOT_YET_IMPLEMENTED("VM: ***none***"); + return 0; +} + +static long chardev_file_fill_pframe(vnode_t *file, pframe_t *pf) +{ + NOT_YET_IMPLEMENTED("VM: ***none***"); + return 0; +} + +static long chardev_file_flush_pframe(vnode_t *file, pframe_t *pf) +{ + NOT_YET_IMPLEMENTED("VM: ***none***"); + return 0; +} + +static ssize_t blockdev_file_read(vnode_t *file, size_t pos, void *buf, + size_t count) +{ + return -ENOTSUP; +} + +static long blockdev_file_write(vnode_t *file, size_t pos, const void *buf, + size_t count) +{ + return -ENOTSUP; +} + +static long blockdev_file_mmap(vnode_t *file, mobj_t **ret) { return -ENOTSUP; } + +static long blockdev_file_fill_pframe(vnode_t *file, pframe_t *pf) +{ + return -ENOTSUP; +} + +static long blockdev_file_flush_pframe(vnode_t *file, pframe_t *pf) +{ + return -ENOTSUP; +} |