/* $OpenBSD: msdosfs_vnops.c,v 1.9 2021/10/06 00:40:41 deraadt Exp $ */ /* $NetBSD: msdosfs_vnops.c,v 1.17 2016/01/30 09:59:27 mlelstv Exp $ */ /*- * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. * Copyright (C) 1994, 1995, 1997 TooLs GmbH. * All rights reserved. * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). * * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by TooLs GmbH. * 4. The name of TooLs GmbH may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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. */ /* * Written by Paul Popelka (paulp@uts.amdahl.com) * * You can do anything you want with this software, just don't say you wrote * it, and don't remove this notice. * * This software is provided "as is". * * The author supplies this software to be publicly redistributed on the * understanding that the author is not responsible for the correct * functioning of this software in any circumstances and is not liable for * any damages caused by this software. * * October 1992 */ #include #include #include #include #include "ffs/buf.h" #include #include "msdos/direntry.h" #include "msdos/denode.h" #include "msdos/msdosfsmount.h" #include "msdos/fat.h" #include "makefs.h" #include "msdos.h" #ifdef MSDOSFS_DEBUG #define DPRINTF(a) printf a #else #define DPRINTF(a) #endif /* * Some general notes: * * In the ufs filesystem the inodes, superblocks, and indirect blocks are * read/written using the mkfsvnode for the filesystem. Blocks that represent * the contents of a file are read/written using the mkfsvnode for the file * (including directories when they are read/written as files). This * presents problems for the dos filesystem because data that should be in * an inode (if dos had them) resides in the directory itself. Since we * must update directory entries without the benefit of having the mkfsvnode * for the directory we must use the mkfsvnode for the filesystem. This means * that when a directory is actually read/written (via read, write, or * readdir, or seek) we must use the mkfsvnode for the filesystem instead of * the mkfsvnode for the directory as would happen in ufs. This is to insure we * retrieve the correct block from the buffer cache since the hash value is * based upon the mkfsvnode address and the desired block number. */ static int msdosfs_wfile(const char *, struct denode *, fsnode *); static void msdosfs_times(struct msdosfsmount *pmp, struct denode *dep, const struct stat *st) { struct timespec at = st->st_atimespec; struct timespec mt = st->st_mtimespec; unix2dostime(&at, pmp->pm_minuteswest, &dep->de_ADate, NULL, NULL); unix2dostime(&mt, pmp->pm_minuteswest, &dep->de_MDate, &dep->de_MTime, NULL); } /* * When we search a directory the blocks containing directory entries are * read and examined. The directory entries contain information that would * normally be in the inode of a unix filesystem. This means that some of * a directory's contents may also be in memory resident denodes (sort of * an inode). This can cause problems if we are searching while some other * process is modifying a directory. To prevent one process from accessing * incompletely modified directory information we depend upon being the * sole owner of a directory block. bread/brelse provide this service. * This being the case, when a process modifies a directory it must first * acquire the disk block that contains the directory entry to be modified. * Then update the disk block and the denode, and then write the disk block * out to disk. This way disk blocks containing directory entries and in * memory denode's will be in synch. */ static int msdosfs_findslot(struct denode *dp, struct componentname *cnp) { daddr_t bn; int error; int slotcount; int slotoffset = 0; int frcn; u_long cluster; int blkoff; u_int diroff; int blsize; struct msdosfsmount *pmp; struct mkfsbuf *bp = 0; struct direntry *dep; u_char dosfilename[12]; int wincnt = 1; int chksum = -1, chksum_ok; int olddos = 1; pmp = dp->de_pmp; switch (unix2dosfn(cnp->cn_nameptr, dosfilename, cnp->cn_namelen, 0)) { case 0: return (EINVAL); case 1: break; case 2: wincnt = winSlotCnt(cnp->cn_nameptr, cnp->cn_namelen) + 1; break; case 3: olddos = 0; wincnt = winSlotCnt(cnp->cn_nameptr, cnp->cn_namelen) + 1; break; } if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) wincnt = 1; /* * Suppress search for slots unless creating * file and at end of pathname, in which case * we watch for a place to put the new file in * case it doesn't already exist. */ slotcount = 0; DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename)); /* * Search the directory pointed at by vdp for the name pointed at * by cnp->cn_nameptr. */ /* * The outer loop ranges over the clusters that make up the * directory. Note that the root directory is different from all * other directories. It has a fixed number of blocks that are not * part of the pool of allocatable clusters. So, we treat it a * little differently. The root directory starts at "cluster" 0. */ diroff = 0; for (frcn = 0; diroff < dp->de_FileSize; frcn++) { if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) { if (error == E2BIG) break; return (error); } error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 0, &bp); if (error) { return (error); } for (blkoff = 0; blkoff < blsize; blkoff += sizeof(struct direntry), diroff += sizeof(struct direntry)) { dep = (struct direntry *)((char *)bp->b_data + blkoff); /* * If the slot is empty and we are still looking * for an empty then remember this one. If the * slot is not empty then check to see if it * matches what we are looking for. If the slot * has never been filled with anything, then the * remainder of the directory has never been used, * so there is no point in searching it. */ if (dep->deName[0] == SLOT_EMPTY || dep->deName[0] == SLOT_DELETED) { /* * Drop memory of previous long matches */ chksum = -1; if (slotcount < wincnt) { slotcount++; slotoffset = diroff; } if (dep->deName[0] == SLOT_EMPTY) { brelse(bp, 0); goto notfound; } } else { /* * If there wasn't enough space for our * winentries, forget about the empty space */ if (slotcount < wincnt) slotcount = 0; /* * Check for Win95 long filename entry */ if (dep->deAttributes == ATTR_WIN95) { if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) continue; chksum = winChkName(cnp->cn_nameptr, cnp->cn_namelen, (struct winentry *)dep, chksum); continue; } /* * Ignore volume labels (anywhere, not just * the root directory). */ if (dep->deAttributes & ATTR_VOLUME) { chksum = -1; continue; } /* * Check for a checksum or name match */ chksum_ok = (chksum == winChksum(dep->deName)); if (!chksum_ok && (!olddos || memcmp(dosfilename, dep->deName, 11))) { chksum = -1; continue; } DPRINTF(("%s(): match blkoff %d, diroff %d\n", __func__, blkoff, diroff)); /* * Remember where this directory * entry came from for whoever did * this lookup. */ dp->de_fndoffset = diroff; dp->de_fndcnt = 0; return EEXIST; } } /* for (blkoff = 0; .... */ /* * Release the buffer holding the directory cluster just * searched. */ brelse(bp, 0); } /* for (frcn = 0; ; frcn++) */ notfound: /* * We hold no disk buffers at this point. */ /* * If we get here we didn't find the entry we were looking for. But * that's ok if we are creating or renaming and are at the end of * the pathname and the directory hasn't been removed. */ DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n", __func__, dp->de_refcnt, slotcount, slotoffset)); /* * Fixup the slot description to point to the place where * we might put the new DOS direntry (putting the Win95 * long name entries before that) */ if (!slotcount) { slotcount = 1; slotoffset = diroff; } if (wincnt > slotcount) { slotoffset += sizeof(struct direntry) * (wincnt - slotcount); } /* * Return an indication of where the new directory * entry should be put. */ dp->de_fndoffset = slotoffset; dp->de_fndcnt = wincnt - 1; /* * We return with the directory locked, so that * the parameters we set up above will still be * valid if we actually decide to do a direnter(). * We return ni_vp == NULL to indicate that the entry * does not currently exist; we leave a pointer to * the (locked) directory inode in ndp->ni_dvp. * * NB - if the directory is unlocked, then this * information cannot be used. */ return 0; } /* * Create a regular file. On entry the directory to contain the file being * created is locked. We must release before we return. */ struct denode * msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node) { struct componentname cn; struct denode ndirent; struct denode *dep; int error; struct stat *st = &node->inode->st; struct msdosfsmount *pmp = pdep->de_pmp; cn.cn_nameptr = node->name; cn.cn_namelen = strlen(node->name); DPRINTF(("%s(name %s, mode 0%o size %zu)\n", __func__, node->name, st->st_mode, (size_t)st->st_size)); /* * If this is the root directory and there is no space left we * can't do anything. This is because the root directory can not * change size. */ if (pdep->de_StartCluster == MSDOSFSROOT && pdep->de_fndoffset >= pdep->de_FileSize) { error = ENOSPC; goto bad; } /* * Create a directory entry for the file, then call createde() to * have it installed. NOTE: DOS files are always executable. We * use the absence of the owner write bit to make the file * readonly. */ memset(&ndirent, 0, sizeof(ndirent)); if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) goto bad; ndirent.de_Attributes = (st->st_mode & S_IWUSR) ? ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY; ndirent.de_StartCluster = 0; ndirent.de_FileSize = 0; ndirent.de_dev = pdep->de_dev; ndirent.de_devvp = pdep->de_devvp; ndirent.de_pmp = pdep->de_pmp; ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; msdosfs_times(pmp, &ndirent, st); if ((error = msdosfs_findslot(pdep, &cn)) != 0) goto bad; if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) goto bad; if ((error = msdosfs_wfile(path, dep, node)) != 0) goto bad; return dep; bad: errno = error; return NULL; } static int msdosfs_updatede(struct denode *dep) { struct mkfsbuf *bp; struct direntry *dirp; int error; dep->de_flag &= ~DE_MODIFIED; error = readde(dep, &bp, &dirp); if (error) return error; DE_EXTERNALIZE(dirp, dep); error = bwrite(bp); return error; } /* * Write data to a file or directory. */ static int msdosfs_wfile(const char *path, struct denode *dep, fsnode *node) { int error, fd; size_t osize = dep->de_FileSize; struct stat *st = &node->inode->st; size_t nsize, offs; struct msdosfsmount *pmp = dep->de_pmp; struct mkfsbuf *bp; char *dat; u_long cn = 0; error = 0; /* XXX: gcc/vax */ DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", __func__, dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster)); if (st->st_size == 0) return 0; /* Don't bother to try to write files larger than the fs limit */ if (st->st_size > MSDOSFS_FILESIZE_MAX) { errno = EFBIG; return -1; } nsize = st->st_size; DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize)); if (nsize > osize) { if ((error = deextend(dep, nsize)) != 0) { errno = error; return -1; } if ((error = msdosfs_updatede(dep)) != 0) { errno = error; return -1; } } if ((fd = open(path, O_RDONLY)) == -1) err(1, "open %s", path); if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)) == MAP_FAILED) { DPRINTF(("%s: mmap %s %s", __func__, node->name, strerror(errno))); close(fd); goto out; } close(fd); for (offs = 0; offs < nsize;) { int blsize, cpsize; daddr_t bn; u_long on = offs & pmp->pm_crbomask; #ifdef HACK cn = dep->de_StartCluster; if (cn == MSDOSFSROOT) { DPRINTF(("%s: bad lbn %lu", __func__, cn)); goto out; } bn = cntobn(pmp, cn); blsize = pmp->pm_bpcluster; #else if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) { DPRINTF(("%s: pcbmap %lu", __func__, bn)); goto out; } #endif DPRINTF(("%s(cn=%lu, bn=%llu/%llu, blsize=%d)\n", __func__, cn, (unsigned long long)bn, (unsigned long long)de_bn2kb(pmp, bn), blsize)); if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 0, &bp)) != 0) { DPRINTF(("bread %d\n", error)); goto out; } cpsize = MINIMUM((nsize - offs), blsize - on); memcpy((char *)bp->b_data + on, dat + offs, cpsize); bwrite(bp); offs += cpsize; } munmap(dat, nsize); return 0; out: munmap(dat, nsize); return error; } static const struct { struct direntry dot; struct direntry dotdot; } dosdirtemplate = { { ". ", " ", /* the . entry */ ATTR_DIRECTORY, /* file attribute */ 0, /* reserved */ 0, { 0, 0 }, { 0, 0 }, /* create time & date */ { 0, 0 }, /* access date */ { 0, 0 }, /* high bits of start cluster */ { 210, 4 }, { 210, 4 }, /* modify time & date */ { 0, 0 }, /* startcluster */ { 0, 0, 0, 0 } /* filesize */ }, { ".. ", " ", /* the .. entry */ ATTR_DIRECTORY, /* file attribute */ 0, /* reserved */ 0, { 0, 0 }, { 0, 0 }, /* create time & date */ { 0, 0 }, /* access date */ { 0, 0 }, /* high bits of start cluster */ { 210, 4 }, { 210, 4 }, /* modify time & date */ { 0, 0 }, /* startcluster */ { 0, 0, 0, 0 } /* filesize */ } }; struct denode * msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) { struct denode ndirent; struct denode *dep; struct componentname cn; struct stat *st = &node->inode->st; struct msdosfsmount *pmp = pdep->de_pmp; int error; u_long newcluster, pcl, bn; daddr_t lbn; struct direntry *denp; struct mkfsbuf *bp; cn.cn_nameptr = node->name; cn.cn_namelen = strlen(node->name); /* * If this is the root directory and there is no space left we * can't do anything. This is because the root directory can not * change size. */ if (pdep->de_StartCluster == MSDOSFSROOT && pdep->de_fndoffset >= pdep->de_FileSize) { error = ENOSPC; goto bad2; } /* * Allocate a cluster to hold the about to be created directory. */ error = clusteralloc(pmp, 0, 1, &newcluster, NULL); if (error) goto bad2; memset(&ndirent, 0, sizeof(ndirent)); ndirent.de_pmp = pmp; ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; msdosfs_times(pmp, &ndirent, st); /* * Now fill the cluster with the "." and ".." entries. And write * the cluster to disk. This way it is there for the parent * directory to be pointing at if there were a crash. */ bn = cntobn(pmp, newcluster); lbn = de_bn2kb(pmp, bn); DPRINTF(("%s(newcluster %lu, bn=%lu, lbn=%lu)\n", __func__, newcluster, bn, lbn)); /* always succeeds */ bp = getblk(pmp->pm_devvp, lbn, pmp->pm_bpcluster, 0, 0); memset(bp->b_data, 0, pmp->pm_bpcluster); memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate); denp = (struct direntry *)bp->b_data; putushort(denp[0].deStartCluster, newcluster); putushort(denp[0].deCDate, ndirent.de_CDate); putushort(denp[0].deCTime, ndirent.de_CTime); denp[0].deCTimeHundredth = ndirent.de_CHun; putushort(denp[0].deADate, ndirent.de_ADate); putushort(denp[0].deMDate, ndirent.de_MDate); putushort(denp[0].deMTime, ndirent.de_MTime); pcl = pdep->de_StartCluster; DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl, pmp->pm_rootdirblk)); if (FAT32(pmp) && pcl == pmp->pm_rootdirblk) pcl = 0; putushort(denp[1].deStartCluster, pcl); putushort(denp[1].deCDate, ndirent.de_CDate); putushort(denp[1].deCTime, ndirent.de_CTime); denp[1].deCTimeHundredth = ndirent.de_CHun; putushort(denp[1].deADate, ndirent.de_ADate); putushort(denp[1].deMDate, ndirent.de_MDate); putushort(denp[1].deMTime, ndirent.de_MTime); if (FAT32(pmp)) { putushort(denp[0].deHighClust, newcluster >> 16); putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16); } else { putushort(denp[0].deHighClust, 0); putushort(denp[1].deHighClust, 0); } if ((error = bwrite(bp)) != 0) goto bad; /* * Now build up a directory entry pointing to the newly allocated * cluster. This will be written to an empty slot in the parent * directory. */ if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) goto bad; ndirent.de_Attributes = ATTR_DIRECTORY; ndirent.de_StartCluster = newcluster; ndirent.de_FileSize = 0; ndirent.de_dev = pdep->de_dev; ndirent.de_devvp = pdep->de_devvp; ndirent.de_pmp = pdep->de_pmp; if ((error = msdosfs_findslot(pdep, &cn)) != 0) goto bad; if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) goto bad; if ((error = msdosfs_updatede(dep)) != 0) goto bad; return dep; bad: clusterfree(pmp, newcluster, NULL); bad2: errno = error; return NULL; }