/* $OpenBSD: vfs_vnops.c,v 1.122 2023/07/10 22:54:40 deraadt Exp $ */ /* $NetBSD: vfs_vnops.c,v 1.20 1996/02/04 02:18:41 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)vfs_vnops.c 8.5 (Berkeley) 12/8/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int vn_read(struct file *, struct uio *, int); int vn_write(struct file *, struct uio *, int); int vn_kqfilter(struct file *, struct knote *); int vn_closefile(struct file *, struct proc *); int vn_seek(struct file *, off_t *, int, struct proc *); const struct fileops vnops = { .fo_read = vn_read, .fo_write = vn_write, .fo_ioctl = vn_ioctl, .fo_kqfilter = vn_kqfilter, .fo_stat = vn_statfile, .fo_close = vn_closefile, .fo_seek = vn_seek, }; /* * Common code for vnode open operations. * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. */ int vn_open(struct nameidata *ndp, int fmode, int cmode) { struct vnode *vp; struct proc *p = ndp->ni_cnd.cn_proc; struct ucred *cred = p->p_ucred; struct vattr va; struct cloneinfo *cip; int error; /* * The only valid flags to pass in here from NDINIT are * KERNELPATH or BYPASSUNVEIL. This function will override the * nameiop based on the fmode and cmode flags, so validate that * our caller has not set other flags or operations in the nameidata * structure. */ KASSERT((ndp->ni_cnd.cn_flags & ~(KERNELPATH|BYPASSUNVEIL)) == 0); KASSERT(ndp->ni_cnd.cn_nameiop == 0); if ((fmode & (FREAD|FWRITE)) == 0) return (EINVAL); if ((fmode & (O_TRUNC | FWRITE)) == O_TRUNC) return (EINVAL); if (fmode & O_CREAT) { ndp->ni_cnd.cn_nameiop = CREATE; ndp->ni_cnd.cn_flags |= LOCKPARENT | LOCKLEAF; if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) ndp->ni_cnd.cn_flags |= FOLLOW; if ((error = namei(ndp)) != 0) return (error); if (ndp->ni_vp == NULL) { VATTR_NULL(&va); va.va_type = VREG; va.va_mode = cmode; if (fmode & O_EXCL) va.va_vaflags |= VA_EXCLUSIVE; error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, &ndp->ni_cnd, &va); vput(ndp->ni_dvp); if (error) return (error); fmode &= ~O_TRUNC; vp = ndp->ni_vp; } else { VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); if (ndp->ni_dvp == ndp->ni_vp) vrele(ndp->ni_dvp); else vput(ndp->ni_dvp); ndp->ni_dvp = NULL; vp = ndp->ni_vp; if (fmode & O_EXCL) { error = EEXIST; goto bad; } fmode &= ~O_CREAT; } } else { ndp->ni_cnd.cn_nameiop = LOOKUP; ndp->ni_cnd.cn_flags |= ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; if ((error = namei(ndp)) != 0) return (error); vp = ndp->ni_vp; } if (vp->v_type == VSOCK) { error = EOPNOTSUPP; goto bad; } if (vp->v_type == VLNK) { error = ELOOP; goto bad; } if ((fmode & O_DIRECTORY) && vp->v_type != VDIR) { error = ENOTDIR; goto bad; } if ((fmode & O_CREAT) == 0) { if (fmode & FREAD) { if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) goto bad; } if (fmode & FWRITE) { if (vp->v_type == VDIR) { error = EISDIR; goto bad; } if ((error = vn_writechk(vp)) != 0 || (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) goto bad; } } if ((fmode & O_TRUNC) && vp->v_type == VREG) { VATTR_NULL(&va); va.va_size = 0; if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) goto bad; } if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) goto bad; if (vp->v_flag & VCLONED) { cip = (struct cloneinfo *)vp->v_data; vp->v_flag &= ~VCLONED; ndp->ni_vp = cip->ci_vp; /* return cloned vnode */ vp->v_data = cip->ci_data; /* restore v_data */ VOP_UNLOCK(vp); /* keep a reference */ vp = ndp->ni_vp; /* for the increment below */ free(cip, M_TEMP, sizeof(*cip)); } if (fmode & FWRITE) vp->v_writecount++; return (0); bad: vput(vp); return (error); } /* * Check for write permissions on the specified vnode. * Prototype text segments cannot be written. */ int vn_writechk(struct vnode *vp) { /* * Disallow write attempts on read-only file systems; * unless the file is a socket or a block or character * device resident on the file system. */ if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_RDONLY)) { switch (vp->v_type) { case VREG: case VDIR: case VLNK: return (EROFS); case VNON: case VCHR: case VSOCK: case VFIFO: case VBAD: case VBLK: break; } } /* * If there's shared text associated with * the vnode, try to free it up once. If * we fail, we can't allow writing. */ if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) return (ETXTBSY); return (0); } /* * Check whether a write operation would exceed the file size rlimit * for the process, if one should be applied for this operation. * If a partial write should take place, the uio is adjusted and the * amount by which the request would have exceeded the limit is returned * via the 'overrun' argument. */ int vn_fsizechk(struct vnode *vp, struct uio *uio, int ioflag, ssize_t *overrun) { struct proc *p = uio->uio_procp; *overrun = 0; if (vp->v_type == VREG && p != NULL && !(ioflag & IO_NOLIMIT)) { rlim_t limit = lim_cur_proc(p, RLIMIT_FSIZE); /* if already at or over the limit, send the signal and fail */ if (uio->uio_offset >= limit) { psignal(p, SIGXFSZ); return (EFBIG); } /* otherwise, clamp the write to stay under the limit */ if (uio->uio_resid > limit - uio->uio_offset) { *overrun = uio->uio_resid - (limit - uio->uio_offset); uio->uio_resid = limit - uio->uio_offset; } } return (0); } /* * Mark a vnode as being the text image of a running process. */ void vn_marktext(struct vnode *vp) { vp->v_flag |= VTEXT; } /* * Vnode close call */ int vn_close(struct vnode *vp, int flags, struct ucred *cred, struct proc *p) { int error; if (flags & FWRITE) vp->v_writecount--; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); error = VOP_CLOSE(vp, flags, cred, p); vput(vp); return (error); } /* * Package up an I/O request on a vnode into a uio and do it. */ int vn_rdwr(enum uio_rw rw, struct vnode *vp, caddr_t base, int len, off_t offset, enum uio_seg segflg, int ioflg, struct ucred *cred, size_t *aresid, struct proc *p) { struct uio auio; struct iovec aiov; int error; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; aiov.iov_base = base; aiov.iov_len = len; auio.uio_resid = len; auio.uio_offset = offset; auio.uio_segflg = segflg; auio.uio_rw = rw; auio.uio_procp = p; if ((ioflg & IO_NODELOCKED) == 0) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if (rw == UIO_READ) { error = VOP_READ(vp, &auio, ioflg, cred); } else { error = VOP_WRITE(vp, &auio, ioflg, cred); } if ((ioflg & IO_NODELOCKED) == 0) VOP_UNLOCK(vp); if (aresid) *aresid = auio.uio_resid; else if (auio.uio_resid && error == 0) error = EIO; return (error); } /* * File table vnode read routine. */ int vn_read(struct file *fp, struct uio *uio, int fflags) { struct vnode *vp = fp->f_data; struct ucred *cred = fp->f_cred; size_t count = uio->uio_resid; off_t offset; int error; KERNEL_LOCK(); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if ((fflags & FO_POSITION) == 0) offset = uio->uio_offset = fp->f_offset; else offset = uio->uio_offset; /* no wrap around of offsets except on character devices */ if (vp->v_type != VCHR && count > LLONG_MAX - offset) { error = EINVAL; goto done; } if (vp->v_type == VDIR) { error = EISDIR; goto done; } error = VOP_READ(vp, uio, (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, cred); if ((fflags & FO_POSITION) == 0) { mtx_enter(&fp->f_mtx); fp->f_offset += count - uio->uio_resid; mtx_leave(&fp->f_mtx); } done: VOP_UNLOCK(vp); KERNEL_UNLOCK(); return (error); } /* * File table vnode write routine. */ int vn_write(struct file *fp, struct uio *uio, int fflags) { struct vnode *vp = fp->f_data; struct ucred *cred = fp->f_cred; int error, ioflag = IO_UNIT; size_t count; KERNEL_LOCK(); /* note: pwrite/pwritev are unaffected by O_APPEND */ if (vp->v_type == VREG && (fp->f_flag & O_APPEND) && (fflags & FO_POSITION) == 0) ioflag |= IO_APPEND; if (fp->f_flag & FNONBLOCK) ioflag |= IO_NDELAY; if ((fp->f_flag & FFSYNC) || (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) ioflag |= IO_SYNC; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if ((fflags & FO_POSITION) == 0) uio->uio_offset = fp->f_offset; count = uio->uio_resid; error = VOP_WRITE(vp, uio, ioflag, cred); if ((fflags & FO_POSITION) == 0) { mtx_enter(&fp->f_mtx); if (ioflag & IO_APPEND) fp->f_offset = uio->uio_offset; else fp->f_offset += count - uio->uio_resid; mtx_leave(&fp->f_mtx); } VOP_UNLOCK(vp); KERNEL_UNLOCK(); return (error); } /* * File table wrapper for vn_stat */ int vn_statfile(struct file *fp, struct stat *sb, struct proc *p) { struct vnode *vp = fp->f_data; return vn_stat(vp, sb, p); } /* * vnode stat routine. */ int vn_stat(struct vnode *vp, struct stat *sb, struct proc *p) { struct vattr va; int error; mode_t mode; error = VOP_GETATTR(vp, &va, p->p_ucred, p); if (error) return (error); /* * Copy from vattr table */ memset(sb, 0, sizeof(*sb)); sb->st_dev = va.va_fsid; sb->st_ino = va.va_fileid; mode = va.va_mode; switch (vp->v_type) { case VREG: mode |= S_IFREG; break; case VDIR: mode |= S_IFDIR; break; case VBLK: mode |= S_IFBLK; break; case VCHR: mode |= S_IFCHR; break; case VLNK: mode |= S_IFLNK; break; case VSOCK: mode |= S_IFSOCK; break; case VFIFO: mode |= S_IFIFO; break; default: return (EBADF); } sb->st_mode = mode; sb->st_nlink = va.va_nlink; sb->st_uid = va.va_uid; sb->st_gid = va.va_gid; sb->st_rdev = va.va_rdev; sb->st_size = va.va_size; sb->st_atim.tv_sec = va.va_atime.tv_sec; sb->st_atim.tv_nsec = va.va_atime.tv_nsec; sb->st_mtim.tv_sec = va.va_mtime.tv_sec; sb->st_mtim.tv_nsec = va.va_mtime.tv_nsec; sb->st_ctim.tv_sec = va.va_ctime.tv_sec; sb->st_ctim.tv_nsec = va.va_ctime.tv_nsec; sb->st_blksize = va.va_blocksize; sb->st_flags = va.va_flags; sb->st_gen = va.va_gen; sb->st_blocks = va.va_bytes / S_BLKSIZE; return (0); } /* * File table vnode ioctl routine. */ int vn_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p) { struct vnode *vp = fp->f_data; struct vattr vattr; int error = ENOTTY; KERNEL_LOCK(); switch (vp->v_type) { case VREG: case VDIR: if (com == FIONREAD) { error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); if (error) break; *(int *)data = vattr.va_size - foffset(fp); } else if (com == FIONBIO || com == FIOASYNC) /* XXX */ error = 0; /* XXX */ break; case VFIFO: case VCHR: case VBLK: error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); if (error == 0 && com == TIOCSCTTY) { struct session *s = p->p_p->ps_session; struct vnode *ovp = s->s_ttyvp; s->s_ttyvp = vp; vref(vp); if (ovp) vrele(ovp); } break; default: break; } KERNEL_UNLOCK(); return (error); } /* * Check that the vnode is still valid, and if so * acquire requested lock. */ int vn_lock(struct vnode *vp, int flags) { int error, xlocked, do_wakeup; do { mtx_enter(&vnode_mtx); if (vp->v_lflag & VXLOCK) { vp->v_lflag |= VXWANT; msleep_nsec(vp, &vnode_mtx, PINOD, "vn_lock", INFSLP); mtx_leave(&vnode_mtx); error = ENOENT; } else { vp->v_lockcount++; mtx_leave(&vnode_mtx); error = VOP_LOCK(vp, flags); mtx_enter(&vnode_mtx); vp->v_lockcount--; do_wakeup = (vp->v_lockcount == 0); xlocked = vp->v_lflag & VXLOCK; mtx_leave(&vnode_mtx); if (error == 0) { if (!xlocked) return (0); /* * The vnode was exclusively locked while * acquiring the requested lock. Release it and * try again. */ error = ENOENT; VOP_UNLOCK(vp); if (do_wakeup) wakeup_one(&vp->v_lockcount); } } } while (flags & LK_RETRY); return (error); } /* * File table vnode close routine. */ int vn_closefile(struct file *fp, struct proc *p) { struct vnode *vp = fp->f_data; struct flock lf; int error; KERNEL_LOCK(); if ((fp->f_iflags & FIF_HASLOCK)) { lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_UNLCK; (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); } error = vn_close(vp, fp->f_flag, fp->f_cred, p); KERNEL_UNLOCK(); return (error); } int vn_kqfilter(struct file *fp, struct knote *kn) { int error; KERNEL_LOCK(); error = VOP_KQFILTER(fp->f_data, fp->f_flag, kn); KERNEL_UNLOCK(); return (error); } int vn_seek(struct file *fp, off_t *offset, int whence, struct proc *p) { struct ucred *cred = p->p_ucred; struct vnode *vp = fp->f_data; struct vattr vattr; off_t newoff; int error = 0; int special; if (vp->v_type == VFIFO) return (ESPIPE); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if (vp->v_type == VCHR) special = 1; else special = 0; switch (whence) { case SEEK_CUR: newoff = fp->f_offset + *offset; break; case SEEK_END: KERNEL_LOCK(); error = VOP_GETATTR(vp, &vattr, cred, p); KERNEL_UNLOCK(); if (error) goto out; newoff = *offset + (off_t)vattr.va_size; break; case SEEK_SET: newoff = *offset; break; default: error = EINVAL; goto out; } if (!special && newoff < 0) { error = EINVAL; goto out; } mtx_enter(&fp->f_mtx); fp->f_offset = newoff; mtx_leave(&fp->f_mtx); *offset = newoff; out: VOP_UNLOCK(vp); return (error); } /* * Common code for vnode access operations. */ /* Check if a directory can be found inside another in the hierarchy */ int vn_isunder(struct vnode *lvp, struct vnode *rvp, struct proc *p) { int error; error = vfs_getcwd_common(lvp, rvp, NULL, NULL, MAXPATHLEN/2, 0, p); if (!error) return (1); return (0); }