X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/4769a870917b98723690aa336d12d0656769528b..0fd474df7001837bde53da0e42e83081827c9641:/lunaix-os/kernel/fs/vfs.c?ds=sidebyside diff --git a/lunaix-os/kernel/fs/vfs.c b/lunaix-os/kernel/fs/vfs.c index 09539c9..32014d3 100644 --- a/lunaix-os/kernel/fs/vfs.c +++ b/lunaix-os/kernel/fs/vfs.c @@ -1,221 +1,1874 @@ +/** + * @file vfs.c + * @author Lunaixsky (zelong56@gmail.com) + * @brief Lunaix virtual file system - an abstraction layer for all file system. + * @version 0.1 + * @date 2022-07-24 + * + * @copyright Copyright (c) 2022 + * + */ + +// Welcome to The Mountain O'Shit! :) + +/* + TODO vfs & device todos checklist + + It is overseen by Twilight Sparkle ;) + + 1. Get inodes hooked into lru (CHECKED) + 2. Get dnodes hooked into lru (CHECKED) + 3. Get inodes properly hashed so they can be reused by underling fs (CHECKED) + 4. (lru) Add a callback function (or destructor) for eviction. (CHECKED) + [good idea] or a constructor/destructor pattern in cake allocator ? + 5. (mount) Figure out a way to identify a busy mount point before unmount + maybe a unified mount_point structure that maintain a referencing + counter on any dnodes within the subtree? Such a counter will only + increament if a file is opened or a dnode is being used as working + directory and decreamenting conversely. (CHECKED) + 6. (mount) Ability to track all mount points (including sub-mounts) + so we can be confident to clean up everything when we + unmount. (CHECKED) + 7. (mount) Figure out a way to acquire the device represented by a dnode. + so it can be used to mount. (e.g. we wish to get `struct device*` + out of the dnode at /dev/sda) + [tip] we should pay attention at twifs and add a private_data field + under struct v_dnode? (CHECKED) + 8. (mount) Then, we should refactor on mount/unmount mechanism. (CHECKED) + 9. (mount) (future) Ability to mount any thing? e.g. Linux can mount a disk + image file using a so called "loopback" pseudo device. Maybe + we can do similar thing in Lunaix? A block device emulation + above the regular file when we mount it on. + 10. (device) device number (dev_t) allocation + [good idea] :: composition (CHECKED) +*/ + #include +#include #include #include #include +#include +#include +#include +#include + +#include -#define PATH_DELIM '/' -#define DNODE_HASHTABLE_BITS 10 -#define DNODE_HASHTABLE_SIZE (1 << DNODE_HASHTABLE_BITS) -#define DNODE_HASH_MASK (DNODE_HASHTABLE_SIZE - 1) -#define DNODE_HASHBITS (32 - DNODE_HASHTABLE_BITS) +#include -#define VFS_ETOOLONG -1 -#define VFS_ENOFS -2 +#define INODE_ACCESSED 0 +#define INODE_MODIFY 1 static struct cake_pile* dnode_pile; static struct cake_pile* inode_pile; +static struct cake_pile* file_pile; static struct cake_pile* superblock_pile; -static struct cake_pile* name_pile; +static struct cake_pile* fd_pile; -static struct v_superblock* root_sb; -static struct hbucket* dnode_cache; +struct v_dnode* vfs_sysroot = NULL; -static int fs_id = 0; - -struct v_dnode* -__new_dnode(); +struct lru_zone *dnode_lru, *inode_lru; -void -__free_dnode(struct v_dnode* dnode); +struct hstr vfs_ddot = HSTR("..", 2); +struct hstr vfs_dot = HSTR(".", 1); +struct hstr vfs_empty = HSTR("", 0); -struct v_superblock* -__new_superblock(); +static int +__vfs_try_evict_dnode(struct lru_node* obj); -void -__free_superblock(struct v_superblock* sb); +static int +__vfs_try_evict_inode(struct lru_node* obj); void vfs_init() { - // 为他们专门创建一个蛋糕堆，而不使用valloc，这样我们可以最小化内部碎片的产生 - dnode_pile = cake_new_pile("dnode", sizeof(struct v_dnode), 1, 0); - inode_pile = cake_new_pile("inode", sizeof(struct v_inode), 1, 0); - name_pile = cake_new_pile("dname", VFS_NAME_MAXLEN, 1, 0); + // 为他们专门创建一个蛋糕堆，而不使用valloc，这样我们可以最小化内碎片的产生 + dnode_pile = cake_new_pile("dnode_cache", sizeof(struct v_dnode), 1, 0); + inode_pile = cake_new_pile("inode_cache", sizeof(struct v_inode), 1, 0); + file_pile = cake_new_pile("file_cache", sizeof(struct v_file), 1, 0); + fd_pile = cake_new_pile("fd_cache", sizeof(struct v_fd), 1, 0); superblock_pile = - cake_new_pile("superblock", sizeof(struct v_superblock), 1, 0); + cake_new_pile("sb_cache", sizeof(struct v_superblock), 1, 0); + + dnode_lru = lru_new_zone("vfs_dnode", __vfs_try_evict_dnode); + inode_lru = lru_new_zone("vfs_inode", __vfs_try_evict_inode); - dnode_cache = valloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket)); + hstr_rehash(&vfs_ddot, HSTR_FULL_HASH); + hstr_rehash(&vfs_dot, HSTR_FULL_HASH); + + // 创建一个根dnode。 + vfs_sysroot = vfs_d_alloc(NULL, &vfs_empty); + vfs_sysroot->parent = vfs_sysroot; + + vfs_ref_dnode(vfs_sysroot); +} + +static inline struct hbucket* +__dcache_hash(struct v_dnode* parent, u32_t* hash) +{ + struct hbucket* d_cache; + u32_t _hash; + + d_cache = parent->super_block->d_cache; + _hash = *hash; + _hash = _hash ^ (_hash >> VFS_HASHBITS); + _hash += (u32_t)__ptr(parent); - // 挂载Lunaix的根文件系统，TwiFS！ - struct filesystem* rootfs = fsm_get("twifs"); - root_sb = __new_superblock(); - rootfs->mount(root_sb, NULL); + *hash = _hash; + return &d_cache[_hash & VFS_HASH_MASK]; } -inline struct hbucket* -__dcache_get_bucket(struct v_dnode* parent, unsigned int hash) +static inline int +__sync_inode_nolock(struct v_inode* inode) { - // 与parent的指针值做加法，来减小碰撞的可能性。 - hash += (uint32_t)parent; - // 确保低位更加随机 - hash = hash ^ (hash >> DNODE_HASHBITS); - return &dnode_cache[hash & DNODE_HASH_MASK]; + pcache_commit_all(inode); + + int errno = ENOTSUP; + if (inode->ops->sync) { + errno = inode->ops->sync(inode); + } + + return errno; } struct v_dnode* vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str) { - struct hbucket* slot = __dcache_get_bucket(parent, str->hash); + if (!str->len || HSTR_EQ(str, &vfs_dot)) + return parent; + + if (HSTR_EQ(str, &vfs_ddot)) { + return parent->parent; + } + + u32_t hash = str->hash; + struct hbucket* slot = __dcache_hash(parent, &hash); struct v_dnode *pos, *n; hashtable_bucket_foreach(slot, pos, n, hash_list) { - if (pos->name.hash == str->hash) { + if (pos->name.hash == hash && pos->parent == parent) { return pos; } } return NULL; } +static void +__vfs_touch_inode(struct v_inode* inode, const int type) +{ + if (type == INODE_MODIFY) { + inode->mtime = clock_unixtime(); + } + + else if (type == INODE_ACCESSED) { + inode->atime = clock_unixtime(); + } + + lru_use_one(inode_lru, &inode->lru); +} + void vfs_dcache_add(struct v_dnode* parent, struct v_dnode* dnode) { - struct hbucket* bucket = __dcache_get_bucket(parent, dnode->name.hash); + assert(parent); + + dnode->ref_count = 1; + dnode->parent = parent; + llist_append(&parent->children, &dnode->siblings); + + struct hbucket* bucket = __dcache_hash(parent, &dnode->name.hash); hlist_add(&bucket->head, &dnode->hash_list); } +void +vfs_dcache_remove(struct v_dnode* dnode) +{ + assert(dnode); + assert(dnode->ref_count == 1); + + llist_delete(&dnode->siblings); + llist_delete(&dnode->aka_list); + hlist_delete(&dnode->hash_list); + + dnode->parent = NULL; + dnode->ref_count = 0; +} + +void +vfs_dcache_rehash(struct v_dnode* new_parent, struct v_dnode* dnode) +{ + assert(new_parent); + + hstr_rehash(&dnode->name, HSTR_FULL_HASH); + vfs_dcache_remove(dnode); + vfs_dcache_add(new_parent, dnode); +} + int -vfs_walk(struct v_dnode* start, const char* path, struct v_dnode** dentry) +vfs_open(struct v_dnode* dnode, struct v_file** file) { - int errno = 0; - int i = 0, j = 0; + struct v_inode* inode = dnode->inode; + + if (!inode || !inode->ops->open) { + return ENOTSUP; + } + + lock_inode(inode); + + struct v_file* vfile = cake_grab(file_pile); + memset(vfile, 0, sizeof(*vfile)); + + vfile->dnode = dnode; + vfile->inode = inode; + vfile->ref_count = 1; + vfile->ops = inode->default_fops; - if (path[0] == PATH_DELIM) { - start = start->super_block->root; - i++; + if (check_regfile_node(inode) && !inode->pg_cache) { + struct pcache* pcache = vzalloc(sizeof(struct pcache)); + pcache_init(pcache); + pcache->master = inode; + inode->pg_cache = pcache; } - struct v_dnode* dnode; - struct v_dnode* current_level = start; - - char name_content[VFS_NAME_MAXLEN]; - struct hstr name = HSTR(name_content, 0); - - char current, lookahead; - do { - current = path[i++]; - lookahead = path[i++]; - if (current != PATH_DELIM) { - if (j >= VFS_NAME_MAXLEN - 1) { - errno = VFS_ETOOLONG; - goto error; - } - name_content[j++] = current; - if (lookahead) { - continue; - } - } + int errno = inode->ops->open(inode, vfile); + if (errno) { + cake_release(file_pile, vfile); + } else { + vfs_ref_dnode(dnode); + inode->open_count++; - name_content[j] = 0; - hstr_rehash(&name, 32); + *file = vfile; + } - dnode = vfs_dcache_lookup(current_level, &name); + unlock_inode(inode); - if (!dnode) { - dnode = __new_dnode(); - strcpy(dnode->name.value, name_content); - dnode->name.hash = name.hash; - dnode->name.len = j; + return errno; +} - if ((errno = - dnode->inode->ops.dir_lookup(current_level->inode, dnode))) { - goto error; - } +void +vfs_assign_inode(struct v_dnode* assign_to, struct v_inode* inode) +{ + if (assign_to->inode) { + llist_delete(&assign_to->aka_list); + assign_to->inode->link_count--; + } - vfs_dcache_add(current_level, dnode); + llist_append(&inode->aka_dnodes, &assign_to->aka_list); + assign_to->inode = inode; + inode->link_count++; +} - dnode->parent = current_level; - llist_append(¤t_level->children, &dnode->siblings); - } +int +vfs_link(struct v_dnode* to_link, struct v_dnode* name) +{ + int errno; - j = 0; - current_level = dnode; - } while (lookahead); + if ((errno = vfs_check_writable(to_link))) { + return errno; + } - *dentry = dnode; - return 0; + lock_inode(to_link->inode); + if (to_link->super_block->root != name->super_block->root) { + errno = EXDEV; + } else if (!to_link->inode->ops->link) { + errno = ENOTSUP; + } else if (!(errno = to_link->inode->ops->link(to_link->inode, name))) { + vfs_assign_inode(name, to_link->inode); + } + unlock_inode(to_link->inode); -error: - __free_dnode(dnode); return errno; } int -vfs_mount(const char* fs_name, bdev_t device, struct v_dnode* mnt_point) +vfs_pclose(struct v_file* file, pid_t pid) { - struct filesystem* fs = fsm_get(fs_name); - if (!fs) - return VFS_ENOFS; - struct v_superblock* sb = __new_superblock(); - sb->dev = device; - sb->fs_id = fs_id++; - + struct v_inode* inode; int errno = 0; - if (!(errno = fs->mount(sb, mnt_point))) { - sb->fs = fs; - llist_append(&root_sb->sb_list, &sb->sb_list); + + inode = file->inode; + + /* + * Prevent dead lock. + * This happened when process is terminated while blocking on read. + * In that case, the process is still holding the inode lock and it + will never get released. + * The unlocking should also include ownership check. + * + * To see why, consider two process both open the same file both with + * fd=x. + * Process A: busy on reading x + * Process B: do nothing with x + * Assuming that, after a very short time, process B get terminated + * while process A is still busy in it's reading business. By this + * design, the inode lock of this file x is get released by B rather + * than A. And this will cause a probable race condition on A if other + * process is writing to this file later after B exit. + */ + + mutex_unlock_for(&inode->lock, pid); + + if (vfs_check_duped_file(file)) { + vfs_unref_file(file); + return 0; + } + + if ((errno = file->ops->close(file))) { + goto done; + } + + vfs_unref_dnode(file->dnode); + cake_release(file_pile, file); + + /* + if the current inode is not being locked by other + threads that does not share same open context, + then we can try to do sync opportunistically + */ + if (mutex_on_hold(&inode->lock)) { + goto done; } + + lock_inode(inode); + pcache_commit_all(inode); + inode->open_count--; + + if (!inode->open_count) { + __sync_inode_nolock(inode); + } + + unlock_inode(inode); + +done: return errno; } int -vfs_unmount(const int fs_id) +vfs_close(struct v_file* file) { - int errno = 0; - struct v_superblock *pos, *n; - llist_for_each(pos, n, &root_sb->sb_list, sb_list) - { - if (pos->fs_id != fs_id) { - continue; - } - if (!(errno = pos->fs->unmount(pos))) { - llist_delete(&pos->sb_list); - __free_superblock(pos); + return vfs_pclose(file, __current->pid); +} + +void +vfs_free_fd(struct v_fd* fd) +{ + cake_release(fd_pile, fd); +} + +int +vfs_isync(struct v_inode* inode) +{ + lock_inode(inode); + + int errno = __sync_inode_nolock(inode); + + unlock_inode(inode); + + return errno; +} + +int +vfs_fsync(struct v_file* file) +{ + int errno; + if ((errno = vfs_check_writable(file->dnode))) { + return errno; + } + + return vfs_isync(file->inode); +} + +int +vfs_alloc_fdslot(int* fd) +{ + for (size_t i = 0; i < VFS_MAX_FD; i++) { + if (!__current->fdtable->fds[i]) { + *fd = i; + return 0; } - break; } - return errno; + return EMFILE; } struct v_superblock* -__new_superblock() +vfs_sb_alloc() { struct v_superblock* sb = cake_grab(superblock_pile); memset(sb, 0, sizeof(*sb)); llist_init_head(&sb->sb_list); - sb->root = __new_dnode(); + + sb->i_cache = vzalloc(VFS_HASHTABLE_SIZE * sizeof(struct hbucket)); + sb->d_cache = vzalloc(VFS_HASHTABLE_SIZE * sizeof(struct hbucket)); + + sb->ref_count = 1; + return sb; +} + +void +vfs_sb_ref(struct v_superblock* sb) +{ + sb->ref_count++; } void -__free_superblock(struct v_superblock* sb) +vfs_sb_unref(struct v_superblock* sb) { - __free_dnode(sb->root); + assert(sb->ref_count); + + sb->ref_count--; + if (likely(sb->ref_count)) { + return; + } + + if (sb->ops.release) { + sb->ops.release(sb); + } + + vfree(sb->i_cache); + vfree(sb->d_cache); + cake_release(superblock_pile, sb); } +static int +__vfs_try_evict_dnode(struct lru_node* obj) +{ + struct v_dnode* dnode = container_of(obj, struct v_dnode, lru); + + if (!dnode->ref_count) { + vfs_d_free(dnode); + return 1; + } + return 0; +} + +static int +__vfs_try_evict_inode(struct lru_node* obj) +{ + struct v_inode* inode = container_of(obj, struct v_inode, lru); + + if (!inode->link_count && !inode->open_count) { + vfs_i_free(inode); + return 1; + } + return 0; +} + struct v_dnode* -__new_dnode() +vfs_d_alloc(struct v_dnode* parent, struct hstr* name) { struct v_dnode* dnode = cake_grab(dnode_pile); - dnode->inode = cake_grab(inode_pile); - dnode->name.value = cake_grab(name_pile); + if (!dnode) { + lru_evict_half(dnode_lru); + + if (!(dnode = cake_grab(dnode_pile))) { + return NULL; + } + } + + memset(dnode, 0, sizeof(*dnode)); + llist_init_head(&dnode->children); + llist_init_head(&dnode->siblings); + llist_init_head(&dnode->aka_list); + mutex_init(&dnode->lock); + + dnode->name = HHSTR(vzalloc(VFS_NAME_MAXLEN), 0, 0); + + hstrcpy(&dnode->name, name); + + if (parent) { + vfs_d_assign_sb(dnode, parent->super_block); + dnode->mnt = parent->mnt; + } + + lru_use_one(dnode_lru, &dnode->lru); + + return dnode; } void -__free_dnode(struct v_dnode* dnode) +vfs_d_free(struct v_dnode* dnode) { - cake_release(inode_pile, dnode->inode); - cake_release(name_pile, dnode->name.value); + assert(dnode->ref_count == 1); + + if (dnode->inode) { + assert(dnode->inode->link_count > 0); + dnode->inode->link_count--; + } + + vfs_dcache_remove(dnode); + // Make sure the children de-referencing their parent. + // With lru presented, the eviction will be propagated over the entire + // detached subtree eventually + struct v_dnode *pos, *n; + llist_for_each(pos, n, &dnode->children, siblings) + { + vfs_dcache_remove(pos); + } + + if (dnode->destruct) { + dnode->destruct(dnode); + } + + vfs_sb_unref(dnode->super_block); + vfree((void*)dnode->name.value); cake_release(dnode_pile, dnode); +} + +struct v_inode* +vfs_i_find(struct v_superblock* sb, u32_t i_id) +{ + struct hbucket* slot = &sb->i_cache[i_id & VFS_HASH_MASK]; + struct v_inode *pos, *n; + hashtable_bucket_foreach(slot, pos, n, hash_list) + { + if (pos->id == i_id) { + lru_use_one(inode_lru, &pos->lru); + return pos; + } + } + + return NULL; +} + +void +vfs_i_addhash(struct v_inode* inode) +{ + struct hbucket* slot = &inode->sb->i_cache[inode->id & VFS_HASH_MASK]; + + hlist_delete(&inode->hash_list); + hlist_add(&slot->head, &inode->hash_list); +} + +struct v_inode* +vfs_i_alloc(struct v_superblock* sb) +{ + assert(sb->ops.init_inode); + + struct v_inode* inode; + if (!(inode = cake_grab(inode_pile))) { + lru_evict_half(inode_lru); + if (!(inode = cake_grab(inode_pile))) { + return NULL; + } + } + + memset(inode, 0, sizeof(*inode)); + mutex_init(&inode->lock); + llist_init_head(&inode->xattrs); + llist_init_head(&inode->aka_dnodes); + + sb->ops.init_inode(sb, inode); + + inode->ctime = clock_unixtime(); + inode->atime = inode->ctime; + inode->mtime = inode->ctime; + + vfs_i_assign_sb(inode, sb); + lru_use_one(inode_lru, &inode->lru); + return inode; +} + +void +vfs_i_free(struct v_inode* inode) +{ + if (inode->pg_cache) { + pcache_release(inode->pg_cache); + vfree(inode->pg_cache); + } + // we don't need to sync inode. + // If an inode can be free, then it must be properly closed. + // Hence it must be synced already! + if (inode->destruct) { + inode->destruct(inode); + } + + vfs_sb_unref(inode->sb); + hlist_delete(&inode->hash_list); + cake_release(inode_pile, inode); +} + +/* ---- System call definition and support ---- */ + +// make a new name when not exists +#define FLOC_MAYBE_MKNAME 1 + +// name must be non-exist and made. +#define FLOC_MKNAME 2 + +// no follow symlink +#define FLOC_NOFOLLOW 4 + +int +vfs_getfd(int fd, struct v_fd** fd_s) +{ + if (TEST_FD(fd) && (*fd_s = __current->fdtable->fds[fd])) { + return 0; + } + return EBADF; +} + +static int +__vfs_mknod(struct v_inode* parent, struct v_dnode* dnode, + unsigned int itype, dev_t* dev) +{ + int errno; + + errno = parent->ops->create(parent, dnode, itype); + if (errno) { + return errno; + } + + return 0; +} + +struct file_locator { + struct v_dnode* dir; + struct v_dnode* file; + bool fresh; +}; + +/** + * @brief unlock the file locator (floc) if possible. + * If the file to be located if not exists, and + * any FLOC_*MKNAME flag is set, then the parent + * dnode will be locked until the file has been properly + * finalised by subsequent logic. + * + * @param floc + */ +static inline void +__floc_try_unlock(struct file_locator* floc) +{ + if (floc->fresh) { + assert(floc->dir); + unlock_dnode(floc->dir); + } +} + +static int +__vfs_try_locate_file(const char* path, + struct file_locator* floc, + int options) +{ + char name_str[VFS_NAME_MAXLEN]; + struct v_dnode *fdir, *file; + struct hstr name = HSTR(name_str, 0); + int errno, woption = 0; + + if ((options & FLOC_NOFOLLOW)) { + woption |= VFS_WALK_NOFOLLOW; + options &= ~FLOC_NOFOLLOW; + } + + floc->fresh = false; + name_str[0] = 0; + errno = vfs_walk_proc(path, &fdir, &name, woption | VFS_WALK_PARENT); + if (errno) { + return errno; + } + + errno = vfs_walk(fdir, name.value, &file, NULL, woption); + + if (errno && errno != ENOENT) { + goto done; + } + + if (!errno) { + if ((options & FLOC_MKNAME)) { + errno = EEXIST; + } + goto done; + } + + // errno == ENOENT + if (!options) { + goto done; + } + + errno = vfs_check_writable(fdir); + if (errno) { + goto done; + } + + floc->fresh = true; + + file = vfs_d_alloc(fdir, &name); + + if (!file) { + return ENOMEM; + } + + lock_dnode(fdir); + + vfs_dcache_add(fdir, file); + +done: + floc->dir = fdir; + floc->file = file; + + return errno; +} + + +static bool +__check_unlinkable(struct v_dnode* dnode) +{ + int acl; + bool wr_self, wr_parent; + struct v_dnode* parent; + + parent = dnode->parent; + acl = dnode->inode->acl; + + wr_self = check_allow_write(dnode->inode); + wr_parent = check_allow_write(parent->inode); + + if (!fsacl_test(acl, svtx)) { + return wr_self; + } + + if (current_euid() == dnode->inode->uid) { + return true; + } + + return wr_self && wr_parent; +} + +int +vfs_do_open(const char* path, int options) +{ + int errno, fd, loptions = 0; + struct v_dnode *dentry, *file; + struct v_file* ofile = NULL; + struct file_locator floc; + struct v_inode* inode; + + if ((options & FO_CREATE)) { + loptions |= FLOC_MAYBE_MKNAME; + } else if ((options & FO_NOFOLLOW)) { + loptions |= FLOC_NOFOLLOW; + } + + errno = __vfs_try_locate_file(path, &floc, loptions); + + if (errno || (errno = vfs_alloc_fdslot(&fd))) { + return errno; + } + + file = floc.file; + dentry = floc.dir; + + if (floc.fresh) { + errno = __vfs_mknod(dentry->inode, file, VFS_IFFILE, NULL); + if (errno) { + vfs_d_free(file); + __floc_try_unlock(&floc); + return errno; + } + + __floc_try_unlock(&floc); + } + + + if ((errno = vfs_open(file, &ofile))) { + return errno; + } + + inode = ofile->inode; + lock_inode(inode); + + struct v_fd* fd_s = cake_grab(fd_pile); + memset(fd_s, 0, sizeof(*fd_s)); + + if ((options & O_TRUNC)) { + file->inode->fsize = 0; + } + + if (vfs_get_dtype(inode->itype) == DT_DIR) { + ofile->f_pos = 0; + } + + fd_s->file = ofile; + fd_s->flags = options; + __current->fdtable->fds[fd] = fd_s; + + unlock_inode(inode); + + return fd; +} + +__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options) +{ + int errno = vfs_do_open(path, options); + return DO_STATUS_OR_RETURN(errno); +} + +__DEFINE_LXSYSCALL1(int, close, int, fd) +{ + struct v_fd* fd_s; + int errno = 0; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done_err; + } + + if ((errno = vfs_close(fd_s->file))) { + goto done_err; + } + + cake_release(fd_pile, fd_s); + __current->fdtable->fds[fd] = 0; + +done_err: + return DO_STATUS(errno); +} + +void +__vfs_readdir_callback(struct dir_context* dctx, + const char* name, + const int len, + const int dtype) +{ + struct lx_dirent* dent = (struct lx_dirent*)dctx->cb_data; + strncpy(dent->d_name, name, MIN(len, DIRENT_NAME_MAX_LEN)); + dent->d_nlen = len; + dent->d_type = dtype; +} + +__DEFINE_LXSYSCALL2(int, sys_readdir, int, fd, struct lx_dirent*, dent) +{ + struct v_fd* fd_s; + int errno; + + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_inode* inode = fd_s->file->inode; + + lock_inode(inode); + + if (!check_directory_node(inode)) { + errno = ENOTDIR; + goto unlock; + } + + if (!check_allow_read(inode)) { + errno = EPERM; + goto unlock; + } + + struct dir_context dctx = (struct dir_context) { + .cb_data = dent, + .read_complete_callback = __vfs_readdir_callback + }; + + if ((errno = fd_s->file->ops->readdir(fd_s->file, &dctx)) != 1) { + goto unlock; + } + dent->d_offset++; + fd_s->file->f_pos++; + +unlock: + unlock_inode(inode); + +done: + return DO_STATUS_OR_RETURN(errno); +} + +__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count) +{ + int errno = 0; + struct v_fd* fd_s; + struct v_inode* inode; + + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_file* file = fd_s->file; + if (check_directory_node(file->inode)) { + errno = EISDIR; + goto done; + } + + if (!check_allow_read(file->inode)) { + errno = EPERM; + goto done; + } + + inode = file->inode; + lock_inode(inode); + + __vfs_touch_inode(inode, INODE_ACCESSED); + + if (check_seqdev_node(inode) || (fd_s->flags & FO_DIRECT)) { + errno = file->ops->read(inode, buf, count, file->f_pos); + } else { + errno = pcache_read(inode, buf, count, file->f_pos); + } + + if (errno > 0) { + file->f_pos += errno; + unlock_inode(inode); + return errno; + } + + unlock_inode(inode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count) +{ + int errno = 0; + struct v_fd* fd_s; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_inode* inode; + struct v_file* file = fd_s->file; + + if ((errno = vfs_check_writable(file->dnode))) { + goto done; + } + + if (check_directory_node(file->inode)) { + errno = EISDIR; + goto done; + } + + inode = file->inode; + lock_inode(inode); + + __vfs_touch_inode(inode, INODE_MODIFY); + if ((fd_s->flags & O_APPEND)) { + file->f_pos = inode->fsize; + } + + if (check_seqdev_node(inode) || (fd_s->flags & FO_DIRECT)) { + errno = file->ops->write(inode, buf, count, file->f_pos); + } else { + errno = pcache_write(inode, buf, count, file->f_pos); + } + + if (errno > 0) { + file->f_pos += errno; + inode->fsize = MAX(inode->fsize, file->f_pos); + + unlock_inode(inode); + return errno; + } + + unlock_inode(inode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options) +{ + int errno = 0; + struct v_fd* fd_s; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_file* file = fd_s->file; + struct v_inode* inode = file->inode; + + if (!file->ops->seek) { + errno = ENOTSUP; + goto done; + } + + if (!check_allow_read(inode)) { + errno = EPERM; + goto done; + } + + lock_inode(inode); + + int overflow = 0; + int fpos = file->f_pos; + + if (vfs_get_dtype(inode->itype) == DT_DIR) { + options = (options != FSEEK_END) ? options : FSEEK_SET; + } + + switch (options) { + case FSEEK_CUR: + overflow = sadd_of((int)file->f_pos, offset, &fpos); + break; + case FSEEK_END: + overflow = sadd_of((int)inode->fsize, offset, &fpos); + break; + case FSEEK_SET: + fpos = offset; + break; + } + + if (overflow) { + errno = EOVERFLOW; + } + else { + errno = file->ops->seek(file, fpos); + } + + unlock_inode(inode); + +done: + return DO_STATUS(errno); +} + +int +vfs_get_path(struct v_dnode* dnode, char* buf, size_t size, int depth) +{ + if (!dnode) { + return 0; + } + + if (depth > 64) { + return ENAMETOOLONG; + } + + size_t len = 0; + + if (dnode->parent != dnode) { + len = vfs_get_path(dnode->parent, buf, size, depth + 1); + } + + if (len >= size) { + return len; + } + + if (!len || buf[len - 1] != VFS_PATH_DELIM) { + buf[len++] = VFS_PATH_DELIM; + } + + size_t cpy_size = MIN(dnode->name.len, size - len); + strncpy(buf + len, dnode->name.value, cpy_size); + len += cpy_size; + + return len; +} + +int +vfs_readlink(struct v_dnode* dnode, char* buf, size_t size) +{ + const char* link; + struct v_inode* inode = dnode->inode; + + if (!check_symlink_node(inode)) { + return EINVAL; + } + + if (!inode->ops->read_symlink) { + return ENOTSUP; + } + + if (!check_allow_read(inode)) { + return EPERM; + } + + lock_inode(inode); + + int errno = inode->ops->read_symlink(inode, &link); + if (errno >= 0) { + strncpy(buf, link, MIN(size, (size_t)errno)); + } + + unlock_inode(inode); + return errno; +} + +int +vfs_get_dtype(int itype) +{ + int dtype = DT_FILE; + if (check_itype(itype, VFS_IFSYMLINK)) { + dtype |= DT_SYMLINK; + } + + if (check_itype(itype, VFS_IFDIR)) { + dtype |= DT_DIR; + return dtype; + } + + // TODO other types + + return dtype; +} + +__DEFINE_LXSYSCALL3(int, realpathat, int, fd, char*, buf, size_t, size) +{ + int errno; + struct v_fd* fd_s; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_dnode* dnode; + errno = vfs_get_path(fd_s->file->dnode, buf, size, 0); + + if (errno >= 0) { + return errno; + } + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL3(int, readlink, const char*, path, char*, buf, size_t, size) +{ + int errno; + struct v_dnode* dnode; + if (!(errno = vfs_walk_proc(path, &dnode, NULL, VFS_WALK_NOFOLLOW))) { + errno = vfs_readlink(dnode, buf, size); + } + + if (errno >= 0) { + return errno; + } + + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL4( + int, readlinkat, int, dirfd, const char*, pathname, char*, buf, size_t, size) +{ + int errno; + struct v_fd* fd_s; + if ((errno = vfs_getfd(dirfd, &fd_s))) { + goto done; + } + + pathname = pathname ? pathname : ""; + + struct v_dnode* dnode; + if (!(errno = vfs_walk( + fd_s->file->dnode, pathname, &dnode, NULL, VFS_WALK_NOFOLLOW))) { + errno = vfs_readlink(fd_s->file->dnode, buf, size); + } + + if (errno >= 0) { + return errno; + } + +done: + return DO_STATUS(errno); +} + +/* + NOTE + When we perform operation that could affect the layout of + directory (i.e., rename, mkdir, rmdir). We must lock the parent dir + whenever possible. This will blocking any ongoing path walking to reach + it hence avoid any partial state. +*/ + +__DEFINE_LXSYSCALL1(int, rmdir, const char*, pathname) +{ + int errno; + struct v_dnode* dnode; + if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) { + return DO_STATUS(errno); + } + + lock_dnode(dnode); + + if (!__check_unlinkable(dnode)) { + errno = EPERM; + goto done; + } + + if ((errno = vfs_check_writable(dnode))) { + goto done; + } + + if ((dnode->super_block->fs->types & FSTYPE_ROFS)) { + errno = EROFS; + goto done; + } + + if (dnode->ref_count > 1 || dnode->inode->open_count) { + errno = EBUSY; + goto done; + } + + if (!llist_empty(&dnode->children)) { + errno = ENOTEMPTY; + goto done; + } + + struct v_dnode* parent = dnode->parent; + + if (!parent) { + errno = EINVAL; + goto done; + } + + lock_dnode(parent); + lock_inode(parent->inode); + + if (check_directory_node(dnode->inode)) { + errno = parent->inode->ops->rmdir(parent->inode, dnode); + if (!errno) { + vfs_dcache_remove(dnode); + } + } else { + errno = ENOTDIR; + } + + unlock_inode(parent->inode); + unlock_dnode(parent); + +done: + unlock_dnode(dnode); + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL1(int, mkdir, const char*, path) +{ + int errno = 0; + struct v_dnode *parent, *dir; + char name_value[VFS_NAME_MAXLEN]; + struct hstr name = HHSTR(name_value, 0, 0); + + if ((errno = vfs_walk_proc(path, &parent, &name, VFS_WALK_PARENT))) { + goto done; + } + + if (!(errno = vfs_walk(parent, name_value, &dir, NULL, 0))) { + errno = EEXIST; + goto done; + } + + if ((errno = vfs_check_writable(parent))) { + goto done; + } + + if (!(dir = vfs_d_alloc(parent, &name))) { + errno = ENOMEM; + goto done; + } + + struct v_inode* inode = parent->inode; + + lock_dnode(parent); + lock_inode(inode); + + if ((parent->super_block->fs->types & FSTYPE_ROFS)) { + errno = ENOTSUP; + } else if (!inode->ops->mkdir) { + errno = ENOTSUP; + } else if (!check_directory_node(inode)) { + errno = ENOTDIR; + } else if (!(errno = inode->ops->mkdir(inode, dir))) { + vfs_dcache_add(parent, dir); + goto cleanup; + } + + vfs_d_free(dir); + +cleanup: + unlock_inode(inode); + unlock_dnode(parent); +done: + return DO_STATUS(errno); +} + +static int +__vfs_do_unlink(struct v_dnode* dnode) +{ + int errno; + struct v_inode* inode = dnode->inode; + + if (dnode->ref_count > 1) { + return EBUSY; + } + + if (!__check_unlinkable(dnode)) { + return EPERM; + } + + if ((errno = vfs_check_writable(dnode))) { + return errno; + } + + lock_inode(inode); + + if (inode->open_count) { + errno = EBUSY; + } else if (!check_directory_node(inode)) { + errno = inode->ops->unlink(inode, dnode); + if (!errno) { + vfs_d_free(dnode); + } + } else { + errno = EISDIR; + } + + unlock_inode(inode); + + return errno; +} + +__DEFINE_LXSYSCALL1(int, unlink, const char*, pathname) +{ + int errno; + struct v_dnode* dnode; + if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) { + goto done; + } + + errno = __vfs_do_unlink(dnode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2(int, unlinkat, int, fd, const char*, pathname) +{ + int errno; + struct v_fd* fd_s; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_dnode* dnode; + if (!(errno = vfs_walk(fd_s->file->dnode, pathname, &dnode, NULL, 0))) { + errno = __vfs_do_unlink(dnode); + } + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2(int, link, const char*, oldpath, const char*, newpath) +{ + int errno; + struct file_locator floc; + struct v_dnode *to_link, *name_file; + + errno = __vfs_try_locate_file(oldpath, &floc, 0); + if (errno) { + goto done; + } + + __floc_try_unlock(&floc); + + to_link = floc.file; + errno = __vfs_try_locate_file(newpath, &floc, FLOC_MKNAME); + if (!errno) { + goto done; + } + + name_file = floc.file; + errno = vfs_link(to_link, name_file); + if (errno) { + vfs_d_free(name_file); + } + +done: + __floc_try_unlock(&floc); + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL1(int, fsync, int, fildes) +{ + int errno; + struct v_fd* fd_s; + + if (!(errno = vfs_getfd(fildes, &fd_s))) { + errno = vfs_fsync(fd_s->file); + } + + return DO_STATUS(errno); +} + +int +vfs_dup_fd(struct v_fd* old, struct v_fd** new) +{ + int errno = 0; + struct v_fd* copied = cake_grab(fd_pile); + + memcpy(copied, old, sizeof(struct v_fd)); + + vfs_ref_file(old->file); + + *new = copied; + + return errno; +} + +int +vfs_dup2(int oldfd, int newfd) +{ + if (newfd == oldfd) { + return newfd; + } + + int errno; + struct v_fd *oldfd_s, *newfd_s; + if ((errno = vfs_getfd(oldfd, &oldfd_s))) { + goto done; + } + + if (!TEST_FD(newfd)) { + errno = EBADF; + goto done; + } + + newfd_s = __current->fdtable->fds[newfd]; + if (newfd_s && (errno = vfs_close(newfd_s->file))) { + goto done; + } + + if (!(errno = vfs_dup_fd(oldfd_s, &newfd_s))) { + __current->fdtable->fds[newfd] = newfd_s; + return newfd; + } + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2(int, dup2, int, oldfd, int, newfd) +{ + return vfs_dup2(oldfd, newfd); +} + +__DEFINE_LXSYSCALL1(int, dup, int, oldfd) +{ + int errno, newfd; + struct v_fd *oldfd_s, *newfd_s; + if ((errno = vfs_getfd(oldfd, &oldfd_s))) { + goto done; + } + + if (!(errno = vfs_alloc_fdslot(&newfd)) && + !(errno = vfs_dup_fd(oldfd_s, &newfd_s))) { + __current->fdtable->fds[newfd] = newfd_s; + return newfd; + } + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2( + int, symlink, const char*, pathname, const char*, link_target) +{ + int errno; + struct file_locator floc; + struct v_dnode *file; + struct v_inode *f_ino; + + errno = __vfs_try_locate_file(pathname, &floc, FLOC_MKNAME); + if (errno) { + goto done; + } + + file = floc.file; + errno = __vfs_mknod(floc.dir->inode, file, VFS_IFSYMLINK, NULL); + if (errno) { + vfs_d_free(file); + goto done; + } + + f_ino = file->inode; + + assert(f_ino); + + errno = vfs_check_writable(file); + if (errno) { + goto done; + } + + if (!f_ino->ops->set_symlink) { + errno = ENOTSUP; + goto done; + } + + lock_inode(f_ino); + + errno = f_ino->ops->set_symlink(f_ino, link_target); + + unlock_inode(f_ino); + +done: + __floc_try_unlock(&floc); + return DO_STATUS(errno); +} + +static int +vfs_do_chdir_nolock(struct proc_info* proc, struct v_dnode* dnode) +{ + if (!check_directory_node(dnode->inode)) { + return ENOTDIR; + } + + if (proc->cwd) { + vfs_unref_dnode(proc->cwd); + } + + vfs_ref_dnode(dnode); + proc->cwd = dnode; + + return 0; +} + +static int +vfs_do_chdir(struct proc_info* proc, struct v_dnode* dnode) +{ + int errno = 0; + + lock_dnode(dnode); + + errno = vfs_do_chdir_nolock(proc, dnode); + + unlock_dnode(dnode); + + return errno; +} + +__DEFINE_LXSYSCALL1(int, chdir, const char*, path) +{ + struct v_dnode* dnode; + int errno = 0; + + if ((errno = vfs_walk_proc(path, &dnode, NULL, 0))) { + goto done; + } + + errno = vfs_do_chdir((struct proc_info*)__current, dnode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL1(int, fchdir, int, fd) +{ + struct v_fd* fd_s; + int errno = 0; + + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + errno = vfs_do_chdir((struct proc_info*)__current, fd_s->file->dnode); + +done: + return DO_STATUS(errno); +} + + +__DEFINE_LXSYSCALL1(int, chroot, const char*, path) +{ + int errno; + struct v_dnode* dnode; + if ((errno = vfs_walk_proc(path, &dnode, NULL, 0))) { + return errno; + } + + lock_dnode(dnode); + + errno = vfs_do_chdir_nolock(__current, dnode); + if (errno) { + unlock_dnode(dnode); + goto done; + } + + __current->root = dnode; + + unlock_dnode(dnode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2(char*, getcwd, char*, buf, size_t, size) +{ + int errno = 0; + char* ret_ptr = 0; + if (size < 2) { + errno = ERANGE; + goto done; + } + + size_t len = 0; + + if (!__current->cwd) { + *buf = VFS_PATH_DELIM; + len = 1; + } else { + len = vfs_get_path(__current->cwd, buf, size, 0); + if (len == size) { + errno = ERANGE; + goto done; + } + } + + buf[len] = '\0'; + + ret_ptr = buf; + +done: + syscall_result(errno); + return ret_ptr; +} + +int +vfs_do_rename(struct v_dnode* current, struct v_dnode* target) +{ + int errno = 0; + if (current->inode->id == target->inode->id) { + // hard link + return 0; + } + + if ((errno = vfs_check_writable(current))) { + return errno; + } + + if (current->ref_count > 1 || target->ref_count > 1) { + return EBUSY; + } + + if (current->super_block != target->super_block) { + return EXDEV; + } + + struct v_dnode* oldparent = current->parent; + struct v_dnode* newparent = target->parent; + + lock_dnode(current); + lock_dnode(target); + if (oldparent) + lock_dnode(oldparent); + if (newparent) + lock_dnode(newparent); + + if (!llist_empty(&target->children)) { + errno = ENOTEMPTY; + unlock_dnode(target); + goto cleanup; + } + + if ((errno = + current->inode->ops->rename(current->inode, current, target))) { + unlock_dnode(target); + goto cleanup; + } + + // re-position current + hstrcpy(¤t->name, &target->name); + vfs_dcache_rehash(newparent, current); + + // detach target + vfs_d_free(target); + + unlock_dnode(target); + +cleanup: + unlock_dnode(current); + if (oldparent) + unlock_dnode(oldparent); + if (newparent) + unlock_dnode(newparent); + + return errno; +} + +__DEFINE_LXSYSCALL2(int, rename, const char*, oldpath, const char*, newpath) +{ + struct v_dnode *cur, *target_parent, *target; + struct hstr name = HSTR(valloc(VFS_NAME_MAXLEN), 0); + int errno = 0; + + if ((errno = vfs_walk_proc(oldpath, &cur, NULL, 0))) { + goto done; + } + + if ((errno = vfs_walk( + __current->cwd, newpath, &target_parent, &name, VFS_WALK_PARENT))) { + goto done; + } + + errno = vfs_walk(target_parent, name.value, &target, NULL, 0); + if (errno == ENOENT) { + target = vfs_d_alloc(target_parent, &name); + vfs_dcache_add(target_parent, target); + } else if (errno) { + goto done; + } + + if (!target) { + errno = ENOMEM; + goto done; + } + + errno = vfs_do_rename(cur, target); + +done: + vfree((void*)name.value); + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL2(int, fstat, int, fd, struct file_stat*, stat) +{ + int errno = 0; + struct v_fd* fds; + + if ((errno = vfs_getfd(fd, &fds))) { + goto done; + } + + struct v_inode* vino = fds->file->inode; + struct device* fdev = vino->sb->dev; + + stat->st_ino = vino->id; + stat->st_blocks = vino->lb_usage; + stat->st_size = vino->fsize; + stat->st_blksize = vino->sb->blksize; + stat->st_nlink = vino->link_count; + stat->st_uid = vino->uid; + stat->st_gid = vino->gid; + + stat->st_ctim = vino->ctime; + stat->st_atim = vino->atime; + stat->st_mtim = vino->mtime; + + stat->st_mode = (vino->itype << 16) | vino->acl; + + stat->st_ioblksize = PAGE_SIZE; + + if (check_device_node(vino)) { + struct device* rdev = resolve_device(vino->data); + if (!rdev) { + errno = EINVAL; + goto done; + } + + stat->st_rdev = (dev_t){.meta = rdev->ident.fn_grp, + .unique = rdev->ident.unique, + .index = dev_uid(rdev) }; + } + + if (fdev) { + stat->st_dev = (dev_t){.meta = fdev->ident.fn_grp, + .unique = fdev->ident.unique, + .index = dev_uid(fdev) }; + } + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL4(int, fchmodat, int, fd, + const char*, path, int, mode, int, flags) +{ + int errno; + struct v_dnode *dnode; + struct v_inode* inode; + + errno = vfs_walkat(fd, path, flags, &dnode); + if (errno) { + goto done; + } + + errno = vfs_check_writable(dnode); + if (errno) { + return errno; + } + + inode = dnode->inode; + lock_inode(inode); + + if (!current_is_root()) { + mode = mode & FSACL_RWXMASK; + } + + inode->acl = mode; + __vfs_touch_inode(inode, INODE_MODIFY); + + unlock_inode(inode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL5(int, fchownat, int, fd, + const char*, path, uid_t, uid, gid_t, gid, int, flags) +{ + int errno; + struct v_dnode *dnode; + struct v_inode *inode; + + errno = vfs_walkat(fd, path, flags, &dnode); + if (errno) { + goto done; + } + + errno = vfs_check_writable(dnode); + if (errno) { + return errno; + } + + inode = dnode->inode; + lock_inode(inode); + + inode->uid = uid; + inode->gid = gid; + __vfs_touch_inode(inode, INODE_MODIFY); + + unlock_inode(inode); + +done: + return DO_STATUS(errno); +} + +__DEFINE_LXSYSCALL4(int, faccessat, int, fd, + const char*, path, int, amode, int, flags) +{ + int errno, acl; + struct v_dnode *dnode; + struct v_inode *inode; + struct user_scope* uscope; + + uid_t tuid; + gid_t tgid; + + errno = vfs_walkat(fd, path, flags, &dnode); + if (errno) { + goto done; + } + + if ((flags & AT_EACCESS)) { + tuid = current_euid(); + tgid = current_egid(); + } + else { + uscope = current_user_scope(); + tuid = uscope->ruid; + tgid = uscope->rgid; + } + + inode = dnode->inode; + + acl = inode->acl; + acl &= amode; + acl &= check_acl_between(inode->uid, inode->gid, tuid, tgid); + if (!acl) { + errno = EACCESS; + } + +done: + return DO_STATUS(errno); } \ No newline at end of file