/* $NetBSD: tmpfs_subr.c,v 1.114 2021/10/20 03:08:17 thorpej Exp $ */ /* * Copyright (c) 2005-2020 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Julio M. Merino Vidal, developed as part of Google's Summer of Code * 2005 program, and by Mindaugas Rasiukevicius. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Efficient memory file system: interfaces for inode and directory entry * construction, destruction and manipulation. * * Reference counting * * The link count of inode (tmpfs_node_t::tn_links) is used as a * reference counter. However, it has slightly different semantics. * * For directories - link count represents directory entries, which * refer to the directories. In other words, it represents the count * of sub-directories. It also takes into account the virtual '.' * entry (which has no real entry in the list). For files - link count * represents the hard links. Since only empty directories can be * removed - link count aligns the reference counting requirements * enough. Note: to check whether directory is not empty, the inode * size (tmpfs_node_t::tn_size) can be used. * * The inode itself, as an object, gathers its first reference when * directory entry is attached via tmpfs_dir_attach(9). For instance, * after regular tmpfs_create(), a file would have a link count of 1, * while directory after tmpfs_mkdir() would have 2 (due to '.'). * * Reclamation * * It should be noted that tmpfs inodes rely on a combination of vnode * reference counting and link counting. That is, an inode can only be * destroyed if its associated vnode is inactive. The destruction is * done on vnode reclamation i.e. tmpfs_reclaim(). It should be noted * that tmpfs_node_t::tn_links being 0 is a destruction criterion. * * If an inode has references within the file system (tn_links > 0) and * its inactive vnode gets reclaimed/recycled - then the association is * broken in tmpfs_reclaim(). In such case, an inode will always pass * tmpfs_lookup() and thus vcache_get() to associate a new vnode. * * Lock order * * vnode_t::v_vlock -> * vnode_t::v_interlock */ #include __KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.114 2021/10/20 03:08:17 thorpej Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static void tmpfs_dir_putseq(tmpfs_node_t *, tmpfs_dirent_t *); /* * Initialize vnode with tmpfs node. */ static void tmpfs_init_vnode(struct vnode *vp, tmpfs_node_t *node) { krwlock_t *slock; KASSERT(node->tn_vnode == NULL); /* Share the interlock with the node. */ if (node->tn_type == VREG) { slock = node->tn_spec.tn_reg.tn_aobj->vmobjlock; rw_obj_hold(slock); uvm_obj_setlock(&vp->v_uobj, slock); } vp->v_tag = VT_TMPFS; vp->v_type = node->tn_type; /* Type-specific initialization. */ switch (vp->v_type) { case VBLK: case VCHR: vp->v_op = tmpfs_specop_p; spec_node_init(vp, node->tn_spec.tn_dev.tn_rdev); break; case VFIFO: vp->v_op = tmpfs_fifoop_p; break; case VDIR: if (node->tn_spec.tn_dir.tn_parent == node) vp->v_vflag |= VV_ROOT; /* FALLTHROUGH */ case VLNK: case VREG: case VSOCK: vp->v_op = tmpfs_vnodeop_p; break; default: panic("bad node type %d", vp->v_type); break; } vp->v_data = node; node->tn_vnode = vp; uvm_vnp_setsize(vp, node->tn_size); KASSERT(node->tn_mode != VNOVAL); cache_enter_id(vp, node->tn_mode, node->tn_uid, node->tn_gid, true); } /* * tmpfs_loadvnode: initialise a vnode for a specified inode. */ int tmpfs_loadvnode(struct mount *mp, struct vnode *vp, const void *key, size_t key_len, const void **new_key) { tmpfs_node_t *node; KASSERT(key_len == sizeof(node)); memcpy(&node, key, key_len); if (node->tn_links == 0) return ENOENT; tmpfs_init_vnode(vp, node); *new_key = &vp->v_data; return 0; } /* * tmpfs_newvnode: allocate a new inode of a specified type and * attach the vonode. */ int tmpfs_newvnode(struct mount *mp, struct vnode *dvp, struct vnode *vp, struct vattr *vap, kauth_cred_t cred, void *extra, size_t *key_len, const void **new_key) { tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); tmpfs_node_t *node, *dnode; if (dvp != NULL) { KASSERT(VOP_ISLOCKED(dvp)); dnode = VP_TO_TMPFS_DIR(dvp); if (dnode->tn_links == 0) return ENOENT; if (vap->va_type == VDIR) { /* Check for maximum links limit. */ if (dnode->tn_links == LINK_MAX) return EMLINK; KASSERT(dnode->tn_links < LINK_MAX); } } else dnode = NULL; node = tmpfs_node_get(tmp); if (node == NULL) return ENOSPC; /* Initially, no references and no associations. */ node->tn_links = 0; node->tn_vnode = NULL; node->tn_holdcount = 0; node->tn_dirent_hint = NULL; /* * XXX Where the pool is backed by a map larger than (4GB * * sizeof(*node)), this may produce duplicate inode numbers * for applications that do not understand 64-bit ino_t. */ node->tn_id = (ino_t)((uintptr_t)node / sizeof(*node)); /* * Make sure the generation number is not zero. * tmpfs_inactive() uses generation zero to mark dead nodes. */ do { node->tn_gen = TMPFS_NODE_GEN_MASK & cprng_fast32(); } while (node->tn_gen == 0); /* Generic initialization. */ KASSERT((int)vap->va_type != VNOVAL); node->tn_type = vap->va_type; node->tn_size = 0; node->tn_flags = 0; node->tn_lockf = NULL; node->tn_tflags = 0; vfs_timestamp(&node->tn_atime); node->tn_birthtime = node->tn_atime; node->tn_ctime = node->tn_atime; node->tn_mtime = node->tn_atime; mutex_init(&node->tn_timelock, MUTEX_DEFAULT, IPL_NONE); if (dvp == NULL) { KASSERT(vap->va_uid != VNOVAL && vap->va_gid != VNOVAL); node->tn_uid = vap->va_uid; node->tn_gid = vap->va_gid; vp->v_vflag |= VV_ROOT; } else { KASSERT(dnode != NULL); node->tn_uid = kauth_cred_geteuid(cred); node->tn_gid = dnode->tn_gid; } KASSERT(vap->va_mode != VNOVAL); node->tn_mode = vap->va_mode; /* Type-specific initialization. */ switch (node->tn_type) { case VBLK: case VCHR: /* Character/block special device. */ KASSERT(vap->va_rdev != VNOVAL); node->tn_spec.tn_dev.tn_rdev = vap->va_rdev; break; case VDIR: /* Directory. */ TAILQ_INIT(&node->tn_spec.tn_dir.tn_dir); node->tn_spec.tn_dir.tn_parent = NULL; node->tn_spec.tn_dir.tn_seq_arena = NULL; node->tn_spec.tn_dir.tn_next_seq = TMPFS_DIRSEQ_START; node->tn_spec.tn_dir.tn_readdir_lastp = NULL; /* Extra link count for the virtual '.' entry. */ node->tn_links++; break; case VFIFO: case VSOCK: break; case VLNK: node->tn_size = 0; node->tn_spec.tn_lnk.tn_link = NULL; break; case VREG: /* Regular file. Create an underlying UVM object. */ node->tn_spec.tn_reg.tn_aobj = uao_create(INT64_MAX - PAGE_SIZE, 0); node->tn_spec.tn_reg.tn_aobj_pages = 0; break; default: panic("bad node type %d", vp->v_type); break; } tmpfs_init_vnode(vp, node); mutex_enter(&tmp->tm_lock); LIST_INSERT_HEAD(&tmp->tm_nodes, node, tn_entries); mutex_exit(&tmp->tm_lock); *key_len = sizeof(vp->v_data); *new_key = &vp->v_data; return 0; } /* * tmpfs_free_node: remove the inode from a list in the mount point and * destroy the inode structures. */ void tmpfs_free_node(tmpfs_mount_t *tmp, tmpfs_node_t *node) { size_t objsz; uint32_t hold; mutex_enter(&tmp->tm_lock); hold = atomic_or_32_nv(&node->tn_holdcount, TMPFS_NODE_RECLAIMED); /* Defer destruction to last thread holding this node. */ if (hold != TMPFS_NODE_RECLAIMED) { mutex_exit(&tmp->tm_lock); return; } LIST_REMOVE(node, tn_entries); mutex_exit(&tmp->tm_lock); switch (node->tn_type) { case VLNK: if (node->tn_size > 0) { tmpfs_strname_free(tmp, node->tn_spec.tn_lnk.tn_link, node->tn_size); } break; case VREG: /* * Calculate the size of inode data, decrease the used-memory * counter, and destroy the unerlying UVM object (if any). */ objsz = PAGE_SIZE * node->tn_spec.tn_reg.tn_aobj_pages; if (objsz != 0) { tmpfs_mem_decr(tmp, objsz); } if (node->tn_spec.tn_reg.tn_aobj != NULL) { uao_detach(node->tn_spec.tn_reg.tn_aobj); } break; case VDIR: KASSERT(node->tn_size == 0); KASSERT(node->tn_spec.tn_dir.tn_seq_arena == NULL); KASSERT(TAILQ_EMPTY(&node->tn_spec.tn_dir.tn_dir)); KASSERT(node->tn_spec.tn_dir.tn_parent == NULL || node == tmp->tm_root); break; default: break; } KASSERT(node->tn_vnode == NULL); KASSERT(node->tn_links == 0); mutex_destroy(&node->tn_timelock); tmpfs_node_put(tmp, node); } /* * tmpfs_construct_node: allocate a new file of specified type and adds it * into the parent directory. * * => Credentials of the caller are used. */ int tmpfs_construct_node(vnode_t *dvp, vnode_t **vpp, struct vattr *vap, struct componentname *cnp, char *target) { tmpfs_mount_t *tmp = VFS_TO_TMPFS(dvp->v_mount); tmpfs_node_t *dnode = VP_TO_TMPFS_DIR(dvp), *node; tmpfs_dirent_t *de, *wde; char *slink = NULL; int ssize = 0; int error; /* Allocate symlink target. */ if (target != NULL) { KASSERT(vap->va_type == VLNK); ssize = strlen(target); KASSERT(ssize < MAXPATHLEN); if (ssize > 0) { slink = tmpfs_strname_alloc(tmp, ssize); if (slink == NULL) return ENOSPC; memcpy(slink, target, ssize); } } /* Allocate a directory entry that points to the new file. */ error = tmpfs_alloc_dirent(tmp, cnp->cn_nameptr, cnp->cn_namelen, &de); if (error) { if (slink != NULL) tmpfs_strname_free(tmp, slink, ssize); return error; } /* Allocate a vnode that represents the new file. */ error = vcache_new(dvp->v_mount, dvp, vap, cnp->cn_cred, NULL, vpp); if (error) { if (slink != NULL) tmpfs_strname_free(tmp, slink, ssize); tmpfs_free_dirent(tmp, de); return error; } error = vn_lock(*vpp, LK_EXCLUSIVE); if (error) { vrele(*vpp); *vpp = NULL; if (slink != NULL) tmpfs_strname_free(tmp, slink, ssize); tmpfs_free_dirent(tmp, de); return error; } node = VP_TO_TMPFS_NODE(*vpp); if (slink != NULL) { node->tn_spec.tn_lnk.tn_link = slink; node->tn_size = ssize; } /* Remove whiteout before adding the new entry. */ if (cnp->cn_flags & ISWHITEOUT) { wde = tmpfs_dir_lookup(dnode, cnp); KASSERT(wde != NULL && wde->td_node == TMPFS_NODE_WHITEOUT); tmpfs_dir_detach(dnode, wde); tmpfs_free_dirent(tmp, wde); } /* Associate inode and attach the entry into the directory. */ tmpfs_dir_attach(dnode, de, node); /* Make node opaque if requested. */ if (cnp->cn_flags & ISWHITEOUT) node->tn_flags |= UF_OPAQUE; /* Update the parent's timestamps. */ tmpfs_update(dvp, TMPFS_UPDATE_MTIME | TMPFS_UPDATE_CTIME); VOP_UNLOCK(*vpp); cache_enter(dvp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); return 0; } /* * tmpfs_alloc_dirent: allocates a new directory entry for the inode. * The directory entry contains a path name component. */ int tmpfs_alloc_dirent(tmpfs_mount_t *tmp, const char *name, uint16_t len, tmpfs_dirent_t **de) { tmpfs_dirent_t *nde; nde = tmpfs_dirent_get(tmp); if (nde == NULL) return ENOSPC; nde->td_name = tmpfs_strname_alloc(tmp, len); if (nde->td_name == NULL) { tmpfs_dirent_put(tmp, nde); return ENOSPC; } nde->td_namelen = len; memcpy(nde->td_name, name, len); nde->td_seq = TMPFS_DIRSEQ_NONE; nde->td_node = NULL; /* for asserts */ *de = nde; return 0; } /* * tmpfs_free_dirent: free a directory entry. */ void tmpfs_free_dirent(tmpfs_mount_t *tmp, tmpfs_dirent_t *de) { KASSERT(de->td_node == NULL); KASSERT(de->td_seq == TMPFS_DIRSEQ_NONE); tmpfs_strname_free(tmp, de->td_name, de->td_namelen); tmpfs_dirent_put(tmp, de); } /* * tmpfs_dir_attach: associate directory entry with a specified inode, * and attach the entry into the directory, specified by vnode. * * => Increases link count on the associated node. * => Increases link count on directory node if our node is VDIR. * => It is caller's responsibility to check for the LINK_MAX limit. * => Triggers kqueue events here. */ void tmpfs_dir_attach(tmpfs_node_t *dnode, tmpfs_dirent_t *de, tmpfs_node_t *node) { vnode_t *dvp = dnode->tn_vnode; int events = NOTE_WRITE; KASSERT(dvp != NULL); KASSERT(VOP_ISLOCKED(dvp)); /* Get a new sequence number. */ KASSERT(de->td_seq == TMPFS_DIRSEQ_NONE); de->td_seq = tmpfs_dir_getseq(dnode, de); /* Associate directory entry and the inode. */ de->td_node = node; if (node != TMPFS_NODE_WHITEOUT) { KASSERT(node->tn_links < LINK_MAX); node->tn_links++; /* Save the hint (might overwrite). */ node->tn_dirent_hint = de; } else if ((dnode->tn_gen & TMPFS_WHITEOUT_BIT) == 0) { /* Flag that there are whiteout entries. */ atomic_or_32(&dnode->tn_gen, TMPFS_WHITEOUT_BIT); } /* Insert the entry to the directory (parent of inode). */ TAILQ_INSERT_TAIL(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); dnode->tn_size += sizeof(tmpfs_dirent_t); uvm_vnp_setsize(dvp, dnode->tn_size); if (node != TMPFS_NODE_WHITEOUT && node->tn_type == VDIR) { /* Set parent. */ KASSERT(node->tn_spec.tn_dir.tn_parent == NULL); node->tn_spec.tn_dir.tn_parent = dnode; /* Increase the link count of parent. */ KASSERT(dnode->tn_links < LINK_MAX); dnode->tn_links++; events |= NOTE_LINK; TMPFS_VALIDATE_DIR(node); } } /* * tmpfs_dir_detach: disassociate directory entry and its inode, * and detach the entry from the directory, specified by vnode. * * => Decreases link count on the associated node. * => Decreases the link count on directory node, if our node is VDIR. * => Triggers kqueue events here. * * => Note: dvp and vp may be NULL only if called by tmpfs_unmount(). */ void tmpfs_dir_detach(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { tmpfs_node_t *node = de->td_node; vnode_t *dvp = dnode->tn_vnode; KASSERT(dvp == NULL || VOP_ISLOCKED(dvp)); if (__predict_true(node != TMPFS_NODE_WHITEOUT)) { /* Deassociate the inode and entry. */ node->tn_dirent_hint = NULL; KASSERT(node->tn_links > 0); node->tn_links--; /* If directory - decrease the link count of parent. */ if (node->tn_type == VDIR) { KASSERT(node->tn_spec.tn_dir.tn_parent == dnode); node->tn_spec.tn_dir.tn_parent = NULL; KASSERT(dnode->tn_links > 0); dnode->tn_links--; } } de->td_node = NULL; /* Remove the entry from the directory. */ if (dnode->tn_spec.tn_dir.tn_readdir_lastp == de) { dnode->tn_spec.tn_dir.tn_readdir_lastp = NULL; } TAILQ_REMOVE(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); dnode->tn_size -= sizeof(tmpfs_dirent_t); tmpfs_dir_putseq(dnode, de); if (dvp) { uvm_vnp_setsize(dvp, dnode->tn_size); } } /* * tmpfs_dir_lookup: find a directory entry in the specified inode. * * Note that the . and .. components are not allowed as they do not * physically exist within directories. */ tmpfs_dirent_t * tmpfs_dir_lookup(tmpfs_node_t *node, struct componentname *cnp) { const char *name = cnp->cn_nameptr; const uint16_t nlen = cnp->cn_namelen; tmpfs_dirent_t *de; KASSERT(VOP_ISLOCKED(node->tn_vnode)); KASSERT(nlen != 1 || !(name[0] == '.')); KASSERT(nlen != 2 || !(name[0] == '.' && name[1] == '.')); TMPFS_VALIDATE_DIR(node); TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { if (de->td_namelen != nlen) continue; if (memcmp(de->td_name, name, nlen) != 0) continue; break; } return de; } /* * tmpfs_dir_cached: get a cached directory entry if it is valid. Used to * avoid unnecessary tmpfs_dir_lookup(). * * => The vnode must be locked. */ tmpfs_dirent_t * tmpfs_dir_cached(tmpfs_node_t *node) { tmpfs_dirent_t *de = node->tn_dirent_hint; KASSERT(VOP_ISLOCKED(node->tn_vnode)); if (de == NULL) { return NULL; } KASSERT(de->td_node == node); /* * Directories always have a valid hint. For files, check if there * are any hard links. If there are - hint might be invalid. */ return (node->tn_type != VDIR && node->tn_links > 1) ? NULL : de; } /* * tmpfs_dir_getseq: get a per-directory sequence number for the entry. * * => Shall not be larger than 2^31 for linux32 compatibility. */ uint32_t tmpfs_dir_getseq(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { uint32_t seq = de->td_seq; vmem_t *seq_arena; vmem_addr_t off; int error __diagused; TMPFS_VALIDATE_DIR(dnode); if (__predict_true(seq != TMPFS_DIRSEQ_NONE)) { /* Already set. */ KASSERT(seq >= TMPFS_DIRSEQ_START); return seq; } /* * The "." and ".." and the end-of-directory have reserved numbers. * The other sequence numbers are allocated as following: * * - The first half of the 2^31 is assigned incrementally. * * - If that range is exceeded, then the second half of 2^31 * is used, but managed by vmem(9). */ seq = dnode->tn_spec.tn_dir.tn_next_seq; KASSERT(seq >= TMPFS_DIRSEQ_START); if (__predict_true(seq < TMPFS_DIRSEQ_END)) { /* First half: just increment and return. */ dnode->tn_spec.tn_dir.tn_next_seq++; return seq; } /* * First half exceeded, use the second half. May need to create * vmem(9) arena for the directory first. */ if ((seq_arena = dnode->tn_spec.tn_dir.tn_seq_arena) == NULL) { seq_arena = vmem_create("tmpfscoo", 0, TMPFS_DIRSEQ_END - 1, 1, NULL, NULL, NULL, 0, VM_SLEEP, IPL_NONE); dnode->tn_spec.tn_dir.tn_seq_arena = seq_arena; KASSERT(seq_arena != NULL); } error = vmem_alloc(seq_arena, 1, VM_SLEEP | VM_BESTFIT, &off); KASSERT(error == 0); KASSERT(off < TMPFS_DIRSEQ_END); seq = off | TMPFS_DIRSEQ_END; return seq; } static void tmpfs_dir_putseq(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { vmem_t *seq_arena = dnode->tn_spec.tn_dir.tn_seq_arena; uint32_t seq = de->td_seq; TMPFS_VALIDATE_DIR(dnode); if (seq == TMPFS_DIRSEQ_NONE || seq < TMPFS_DIRSEQ_END) { /* First half (or no sequence number set yet). */ KASSERT(de->td_seq >= TMPFS_DIRSEQ_START); } else { /* Second half. */ KASSERT(seq_arena != NULL); KASSERT(seq >= TMPFS_DIRSEQ_END); seq &= ~TMPFS_DIRSEQ_END; vmem_free(seq_arena, seq, 1); } de->td_seq = TMPFS_DIRSEQ_NONE; /* Empty? We can reset. */ if (seq_arena && dnode->tn_size == 0) { dnode->tn_spec.tn_dir.tn_seq_arena = NULL; dnode->tn_spec.tn_dir.tn_next_seq = TMPFS_DIRSEQ_START; vmem_destroy(seq_arena); } } /* * tmpfs_dir_lookupbyseq: lookup a directory entry by the sequence number. */ tmpfs_dirent_t * tmpfs_dir_lookupbyseq(tmpfs_node_t *node, off_t seq) { tmpfs_dirent_t *de = node->tn_spec.tn_dir.tn_readdir_lastp; TMPFS_VALIDATE_DIR(node); /* * First, check the cache. If does not match - perform a lookup. */ if (de && de->td_seq == seq) { KASSERT(de->td_seq >= TMPFS_DIRSEQ_START); KASSERT(de->td_seq != TMPFS_DIRSEQ_NONE); return de; } TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { KASSERT(de->td_seq >= TMPFS_DIRSEQ_START); KASSERT(de->td_seq != TMPFS_DIRSEQ_NONE); if (de->td_seq == seq) return de; } return NULL; } /* * tmpfs_dir_getdotents: helper function for tmpfs_readdir() to get the * dot meta entries, that is, "." or "..". Copy it to the UIO space. */ static int tmpfs_dir_getdotents(tmpfs_node_t *node, struct dirent *dp, struct uio *uio) { tmpfs_dirent_t *de; off_t next = 0; int error; switch (uio->uio_offset) { case TMPFS_DIRSEQ_DOT: dp->d_fileno = node->tn_id; strlcpy(dp->d_name, ".", sizeof(dp->d_name)); next = TMPFS_DIRSEQ_DOTDOT; break; case TMPFS_DIRSEQ_DOTDOT: dp->d_fileno = node->tn_spec.tn_dir.tn_parent->tn_id; strlcpy(dp->d_name, "..", sizeof(dp->d_name)); de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); next = de ? tmpfs_dir_getseq(node, de) : TMPFS_DIRSEQ_EOF; break; default: KASSERT(false); } dp->d_type = DT_DIR; dp->d_namlen = strlen(dp->d_name); dp->d_reclen = _DIRENT_SIZE(dp); if (dp->d_reclen > uio->uio_resid) { return EJUSTRETURN; } if ((error = uiomove(dp, dp->d_reclen, uio)) != 0) { return error; } uio->uio_offset = next; return error; } /* * tmpfs_dir_getdents: helper function for tmpfs_readdir. * * => Returns as much directory entries as can fit in the uio space. * => The read starts at uio->uio_offset. */ int tmpfs_dir_getdents(tmpfs_node_t *node, struct uio *uio, off_t *cntp) { tmpfs_dirent_t *de; struct dirent dent; int error = 0; KASSERT(VOP_ISLOCKED(node->tn_vnode)); TMPFS_VALIDATE_DIR(node); /* * First check for the "." and ".." cases. * Note: tmpfs_dir_getdotents() will "seek" for us. */ memset(&dent, 0, sizeof(dent)); if (uio->uio_offset == TMPFS_DIRSEQ_DOT) { if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) { goto done; } (*cntp)++; } if (uio->uio_offset == TMPFS_DIRSEQ_DOTDOT) { if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) { goto done; } (*cntp)++; } /* Done if we reached the end. */ if (uio->uio_offset == TMPFS_DIRSEQ_EOF) { goto done; } /* Locate the directory entry given by the given sequence number. */ de = tmpfs_dir_lookupbyseq(node, uio->uio_offset); if (de == NULL) { error = EINVAL; goto done; } /* * Read as many entries as possible; i.e., until we reach the end * of the directory or we exhaust UIO space. */ do { if (de->td_node == TMPFS_NODE_WHITEOUT) { dent.d_fileno = 1; dent.d_type = DT_WHT; } else { dent.d_fileno = de->td_node->tn_id; dent.d_type = vtype2dt(de->td_node->tn_type); } dent.d_namlen = de->td_namelen; KASSERT(de->td_namelen < sizeof(dent.d_name)); memcpy(dent.d_name, de->td_name, de->td_namelen); dent.d_name[de->td_namelen] = '\0'; dent.d_reclen = _DIRENT_SIZE(&dent); if (dent.d_reclen > uio->uio_resid) { /* Exhausted UIO space. */ error = EJUSTRETURN; break; } /* Copy out the directory entry and continue. */ error = uiomove(&dent, dent.d_reclen, uio); if (error) { break; } (*cntp)++; de = TAILQ_NEXT(de, td_entries); } while (uio->uio_resid > 0 && de); /* Cache the last entry or clear and mark EOF. */ uio->uio_offset = de ? tmpfs_dir_getseq(node, de) : TMPFS_DIRSEQ_EOF; node->tn_spec.tn_dir.tn_readdir_lastp = de; done: tmpfs_update(node->tn_vnode, TMPFS_UPDATE_ATIME); if (error == EJUSTRETURN) { /* Exhausted UIO space - just return. */ error = 0; } KASSERT(error >= 0); return error; } /* * tmpfs_reg_resize: resize the underlying UVM object associated with the * specified regular file. */ int tmpfs_reg_resize(struct vnode *vp, off_t newsize) { tmpfs_mount_t *tmp = VFS_TO_TMPFS(vp->v_mount); tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); struct uvm_object *uobj = node->tn_spec.tn_reg.tn_aobj; size_t newpages, oldpages; off_t oldsize; KASSERT(vp->v_type == VREG); KASSERT(newsize >= 0); oldsize = node->tn_size; oldpages = round_page(oldsize) >> PAGE_SHIFT; newpages = round_page(newsize) >> PAGE_SHIFT; KASSERT(oldpages == node->tn_spec.tn_reg.tn_aobj_pages); if (newsize == oldsize) { return 0; } if (newpages > oldpages) { /* Increase the used-memory counter if getting extra pages. */ if (!tmpfs_mem_incr(tmp, (newpages - oldpages) << PAGE_SHIFT)) { return ENOSPC; } } else if (newsize < oldsize) { size_t zerolen; zerolen = MIN(round_page(newsize), node->tn_size) - newsize; ubc_zerorange(uobj, newsize, zerolen, UBC_VNODE_FLAGS(vp)); } node->tn_spec.tn_reg.tn_aobj_pages = newpages; node->tn_size = newsize; uvm_vnp_setsize(vp, newsize); /* * Free "backing store". */ if (newpages < oldpages) { rw_enter(uobj->vmobjlock, RW_WRITER); uao_dropswap_range(uobj, newpages, oldpages); rw_exit(uobj->vmobjlock); /* Decrease the used-memory counter. */ tmpfs_mem_decr(tmp, (oldpages - newpages) << PAGE_SHIFT); } return 0; } /* * tmpfs_chflags: change flags of the given vnode. */ int tmpfs_chflags(vnode_t *vp, int flags, kauth_cred_t cred, lwp_t *l) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); kauth_action_t action = KAUTH_VNODE_WRITE_FLAGS; int error; bool changing_sysflags = false; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* * If the new flags have non-user flags that are different than * those on the node, we need special permission to change them. */ if ((flags & SF_SETTABLE) != (node->tn_flags & SF_SETTABLE)) { action |= KAUTH_VNODE_WRITE_SYSFLAGS; changing_sysflags = true; } /* * Indicate that this node's flags have system attributes in them if * that's the case. */ if (node->tn_flags & (SF_IMMUTABLE | SF_APPEND)) { action |= KAUTH_VNODE_HAS_SYSFLAGS; } error = kauth_authorize_vnode(cred, action, vp, NULL, genfs_can_chflags(vp, cred, node->tn_uid, changing_sysflags)); if (error) return error; /* * Set the flags. If we're not setting non-user flags, be careful not * to overwrite them. * * XXX: Can't we always assign here? if the system flags are different, * the code above should catch attempts to change them without * proper permissions, and if we're here it means it's okay to * change them... */ if (!changing_sysflags) { /* Clear all user-settable flags and re-set them. */ node->tn_flags &= SF_SETTABLE; node->tn_flags |= (flags & UF_SETTABLE); } else { node->tn_flags = flags; } tmpfs_update(vp, TMPFS_UPDATE_CTIME); return 0; } /* * tmpfs_chmod: change access mode on the given vnode. */ int tmpfs_chmod(vnode_t *vp, mode_t mode, kauth_cred_t cred, lwp_t *l) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_SECURITY, vp, NULL, genfs_can_chmod(vp, cred, node->tn_uid, node->tn_gid, mode)); if (error) { return error; } node->tn_mode = (mode & ALLPERMS); tmpfs_update(vp, TMPFS_UPDATE_CTIME); cache_enter_id(vp, node->tn_mode, node->tn_uid, node->tn_gid, true); return 0; } /* * tmpfs_chown: change ownership of the given vnode. * * => At least one of uid or gid must be different than VNOVAL. * => Attribute is unchanged for VNOVAL case. */ int tmpfs_chown(vnode_t *vp, uid_t uid, gid_t gid, kauth_cred_t cred, lwp_t *l) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Assign default values if they are unknown. */ KASSERT(uid != VNOVAL || gid != VNOVAL); if (uid == VNOVAL) { uid = node->tn_uid; } if (gid == VNOVAL) { gid = node->tn_gid; } /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; error = kauth_authorize_vnode(cred, KAUTH_VNODE_CHANGE_OWNERSHIP, vp, NULL, genfs_can_chown(vp, cred, node->tn_uid, node->tn_gid, uid, gid)); if (error) { return error; } node->tn_uid = uid; node->tn_gid = gid; tmpfs_update(vp, TMPFS_UPDATE_CTIME); cache_enter_id(vp, node->tn_mode, node->tn_uid, node->tn_gid, true); return 0; } /* * tmpfs_chsize: change size of the given vnode. */ int tmpfs_chsize(vnode_t *vp, u_quad_t size, kauth_cred_t cred, lwp_t *l) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); const off_t length = size; int error; KASSERT(VOP_ISLOCKED(vp)); /* Decide whether this is a valid operation based on the file type. */ switch (vp->v_type) { case VDIR: return EISDIR; case VREG: if (vp->v_mount->mnt_flag & MNT_RDONLY) { return EROFS; } break; case VBLK: case VCHR: case VFIFO: /* * Allow modifications of special files even if in the file * system is mounted read-only (we are not modifying the * files themselves, but the objects they represent). */ return 0; default: return EOPNOTSUPP; } /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) { return EPERM; } if (length < 0) { return EINVAL; } /* Note: tmpfs_reg_resize() will raise NOTE_EXTEND and NOTE_ATTRIB. */ if (node->tn_size != length && (error = tmpfs_reg_resize(vp, length)) != 0) { return error; } tmpfs_update(vp, TMPFS_UPDATE_CTIME | TMPFS_UPDATE_MTIME); return 0; } /* * tmpfs_chtimes: change access and modification times for vnode. */ int tmpfs_chtimes(vnode_t *vp, const struct timespec *atime, const struct timespec *mtime, const struct timespec *btime, int vaflags, kauth_cred_t cred, lwp_t *l) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_TIMES, vp, NULL, genfs_can_chtimes(vp, cred, node->tn_uid, vaflags)); if (error) return error; mutex_enter(&node->tn_timelock); if (atime->tv_sec != VNOVAL) { atomic_and_uint(&node->tn_tflags, ~TMPFS_UPDATE_ATIME); node->tn_atime = *atime; } if (mtime->tv_sec != VNOVAL) { atomic_and_uint(&node->tn_tflags, ~TMPFS_UPDATE_MTIME); node->tn_mtime = *mtime; } if (btime->tv_sec != VNOVAL) { node->tn_birthtime = *btime; } mutex_exit(&node->tn_timelock); return 0; } /* * tmpfs_update_locked: update the timestamps as indicated by the flags. */ void tmpfs_update_locked(vnode_t *vp, unsigned tflags) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); struct timespec nowtm; KASSERT(mutex_owned(&node->tn_timelock)); if ((tflags |= atomic_swap_uint(&node->tn_tflags, 0)) == 0) { return; } vfs_timestamp(&nowtm); if (tflags & TMPFS_UPDATE_ATIME) { node->tn_atime = nowtm; } if (tflags & TMPFS_UPDATE_MTIME) { node->tn_mtime = nowtm; } if (tflags & TMPFS_UPDATE_CTIME) { node->tn_ctime = nowtm; } } /* * tmpfs_update: update the timestamps as indicated by the flags. */ void tmpfs_update(vnode_t *vp, unsigned tflags) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); if ((tflags | atomic_load_relaxed(&node->tn_tflags)) == 0) { return; } mutex_enter(&node->tn_timelock); tmpfs_update_locked(vp, tflags); mutex_exit(&node->tn_timelock); } /* * tmpfs_update_lazily: schedule a deferred timestamp update. */ void tmpfs_update_lazily(vnode_t *vp, unsigned tflags) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); unsigned cur; cur = atomic_load_relaxed(&node->tn_tflags); if ((cur & tflags) != tflags) { atomic_or_uint(&node->tn_tflags, tflags); return; } }