From 68d7945627a349348497d3b65e569884aac0a98f Mon Sep 17 00:00:00 2001 From: kan Date: Fri, 27 Feb 2004 22:02:15 +0000 Subject: [PATCH] Move the code dealing with vnode out of several functions into a single helper function vm_mmap_vnode. Discussed with: jeffr,alc (a while ago) --- sys/vm/vm_mmap.c | 292 ++++++++++++++++++++++------------------------- 1 file changed, 136 insertions(+), 156 deletions(-) diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c index 6f438706a4c..380934b6176 100644 --- a/sys/vm/vm_mmap.c +++ b/sys/vm/vm_mmap.c @@ -110,6 +110,9 @@ vmmapentry_rsrc_init(dummy) max_proc_mmap /= 100; } +static int vm_mmap_vnode(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *, + int *, struct vnode *, vm_ooffset_t, vm_object_t *); + /* * MPSAFE */ @@ -203,17 +206,15 @@ mmap(td, uap) struct thread *td; struct mmap_args *uap; { - struct file *fp = NULL; + struct file *fp; struct vnode *vp; vm_offset_t addr; vm_size_t size, pageoff; vm_prot_t prot, maxprot; void *handle; int flags, error; - int disablexworkaround; off_t pos; struct vmspace *vms = td->td_proc->p_vmspace; - vm_object_t obj; addr = (vm_offset_t) uap->addr; size = uap->len; @@ -221,7 +222,6 @@ mmap(td, uap) flags = uap->flags; pos = uap->pos; - vp = NULL; fp = NULL; /* make sure mapping fits into numeric range etc */ if ((ssize_t) uap->len < 0 || @@ -284,7 +284,6 @@ mmap(td, uap) lim_max(td->td_proc, RLIMIT_DATA)); PROC_UNLOCK(td->td_proc); } - mtx_lock(&Giant); /* syscall marked mp-safe but isn't */ do { if (flags & MAP_ANON) { /* @@ -306,7 +305,6 @@ mmap(td, uap) error = EINVAL; goto done; } - /* * POSIX shared-memory objects are defined to have * kernel persistence, and are not defined to support @@ -318,60 +316,6 @@ mmap(td, uap) if (fp->f_flag & FPOSIXSHM) flags |= MAP_NOSYNC; vp = fp->f_vnode; - error = vget(vp, LK_EXCLUSIVE, td); - if (error) - goto done; - if (vp->v_type != VREG && vp->v_type != VCHR) { - error = EINVAL; - goto done; - } - if (vp->v_type == VREG) { - /* - * Get the proper underlying object - */ - if (VOP_GETVOBJECT(vp, &obj) != 0) { - error = EINVAL; - goto done; - } - if (obj->handle != vp) { - vput(vp); - vp = (struct vnode*)obj->handle; - vget(vp, LK_EXCLUSIVE, td); - } - } - /* - * XXX hack to handle use of /dev/zero to map anon memory (ala - * SunOS). - */ - if ((vp->v_type == VCHR) && - (vp->v_rdev->si_devsw->d_flags & D_MMAP_ANON)) { - handle = NULL; - maxprot = VM_PROT_ALL; - flags |= MAP_ANON; - pos = 0; - break; - } - /* - * cdevs does not provide private mappings of any kind. - */ - /* - * However, for XIG X server to continue to work, - * we should allow the superuser to do it anyway. - * We only allow it at securelevel < 1. - * (Because the XIG X server writes directly to video - * memory via /dev/mem, it should never work at any - * other securelevel. - * XXX this will have to go - */ - if (securelevel_ge(td->td_ucred, 1)) - disablexworkaround = 1; - else - disablexworkaround = suser(td); - if (vp->v_type == VCHR && disablexworkaround && - (flags & (MAP_PRIVATE|MAP_COPY))) { - error = EINVAL; - goto done; - } /* * Ensure that file and memory protections are * compatible. Note that we only worry about @@ -393,26 +337,11 @@ mmap(td, uap) * MAP_SHARED or via the implicit sharing of character * device mappings), and we are trying to get write * permission although we opened it without asking - * for it, bail out. Check for superuser, only if - * we're at securelevel < 1, to allow the XIG X server - * to continue to work. + * for it, bail out. */ - if ((flags & MAP_SHARED) != 0 || - (vp->v_type == VCHR && disablexworkaround)) { + if ((flags & MAP_SHARED) != 0 || vp->v_type == VCHR) { if ((fp->f_flag & FWRITE) != 0) { - struct vattr va; - if ((error = - VOP_GETATTR(vp, &va, - td->td_ucred, td))) { - goto done; - } - if ((va.va_flags & - (SF_SNAPSHOT|IMMUTABLE|APPEND)) == 0) { - maxprot |= VM_PROT_WRITE; - } else if (prot & PROT_WRITE) { - error = EPERM; - goto done; - } + maxprot |= VM_PROT_WRITE; } else if ((prot & PROT_WRITE) != 0) { error = EACCES; goto done; @@ -420,7 +349,6 @@ mmap(td, uap) } else { maxprot |= VM_PROT_WRITE; } - handle = (void *)vp; } while (0); @@ -435,28 +363,11 @@ mmap(td, uap) goto done; } - error = 0; -#ifdef MAC - if (handle != NULL && (flags & MAP_SHARED) != 0) { - error = mac_check_vnode_mmap(td->td_ucred, - (struct vnode *)handle, prot); - } -#endif - if (vp != NULL) { - vput(vp); - vp = NULL; - } - mtx_unlock(&Giant); - if (error == 0) - error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot, - flags, handle, pos); - mtx_lock(&Giant); + error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot, + flags, handle, pos); if (error == 0) td->td_retval[0] = (register_t) (addr + pageoff); done: - if (vp) - vput(vp); - mtx_unlock(&Giant); if (fp) fdrop(fp, td); @@ -1175,6 +1086,124 @@ kern_munlock(td, addr, size) return (error == KERN_SUCCESS ? 0 : ENOMEM); } +/* + * vm_mmap_vnode() + * + * MPSAFE + * + * Helper function for vm_mmap. Perform sanity check specific for mmap + * operations on vnodes. + */ +int +vm_mmap_vnode(struct thread *td, vm_size_t objsize, + vm_prot_t prot, vm_prot_t *maxprotp, int *flagsp, + struct vnode *vp, vm_ooffset_t foff, vm_object_t *objp) +{ + struct vattr va; + void *handle; + vm_object_t obj; + int disablexworkaround, error, flags, type; + + mtx_lock(&Giant); + if ((error = vget(vp, LK_EXCLUSIVE, td)) != 0) { + mtx_unlock(&Giant); + return (error); + } + flags = *flagsp; + if (vp->v_type == VREG) { + /* + * Get the proper underlying object + */ + if (VOP_GETVOBJECT(vp, &obj) != 0) { + error = EINVAL; + goto done; + } + if (obj->handle != vp) { + vput(vp); + vp = (struct vnode*)obj->handle; + vget(vp, LK_EXCLUSIVE, td); + } + type = OBJT_VNODE; + handle = vp; + } else if (vp->v_type == VCHR) { + type = OBJT_DEVICE; + handle = vp->v_rdev; + + if(vp->v_rdev->si_devsw->d_flags & D_MMAP_ANON) { + *maxprotp = VM_PROT_ALL; + *flagsp |= MAP_ANON; + error = 0; + goto done; + } + /* + * cdevs does not provide private mappings of any kind. + */ + /* + * However, for XIG X server to continue to work, + * we should allow the superuser to do it anyway. + * We only allow it at securelevel < 1. + * (Because the XIG X server writes directly to video + * memory via /dev/mem, it should never work at any + * other securelevel. + * XXX this will have to go + */ + if (securelevel_ge(td->td_ucred, 1)) + disablexworkaround = 1; + else + disablexworkaround = suser(td); + if (disablexworkaround && (flags & (MAP_PRIVATE|MAP_COPY))) { + error = EINVAL; + goto done; + } + /* + * Force device mappings to be shared. + */ + flags &= ~(MAP_PRIVATE|MAP_COPY); + flags |= MAP_SHARED; + } else { + error = EINVAL; + goto done; + } + if ((error = VOP_GETATTR(vp, &va, td->td_ucred, td))) { + goto done; + } + if ((flags & MAP_SHARED) != 0) { + if ((va.va_flags & (SF_SNAPSHOT|IMMUTABLE|APPEND)) != 0) { + if (prot & PROT_WRITE) { + error = EPERM; + goto done; + } + *maxprotp &= ~VM_PROT_WRITE; + } +#ifdef MAC + error = mac_check_vnode_mmap(td->td_ucred, vp, prot); + if (error != 0) + goto done; +#endif + } + /* + * If it is a regular file without any references + * we do not need to sync it. + * Adjust object size to be the size of actual file. + */ + if (vp->v_type == VREG) { + objsize = round_page(va.va_size); + if (va.va_nlink == 0) + flags |= MAP_NOSYNC; + } + obj = vm_pager_allocate(type, handle, objsize, prot, foff); + if (obj == NULL) { + error = (type == OBJT_DEVICE ? EINVAL : ENOMEM); + goto done; + } + *objp = obj; + *flagsp = flags; +done: + vput(vp); + mtx_unlock(&Giant); + return (error); +} + /* * vm_mmap() * @@ -1191,8 +1220,6 @@ vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot, { boolean_t fitit; vm_object_t object; - struct vnode *vp = NULL; - objtype_t type; int rv = KERN_SUCCESS; vm_ooffset_t objsize; int docow, error; @@ -1231,75 +1258,28 @@ vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot, fitit = FALSE; (void) vm_map_remove(map, *addr, *addr + size); } - /* * Lookup/allocate object. */ - if (flags & MAP_ANON) { - type = OBJT_DEFAULT; - /* - * Unnamed anonymous regions always start at 0. - */ - if (handle == 0) - foff = 0; - } else { - vp = (struct vnode *) handle; - mtx_lock(&Giant); - error = vget(vp, LK_EXCLUSIVE, td); + if (handle != NULL) { + error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, + handle, foff, &object); if (error) { - mtx_unlock(&Giant); return (error); } - if (vp->v_type == VCHR) { - type = OBJT_DEVICE; - handle = vp->v_rdev; - vput(vp); - mtx_unlock(&Giant); - } else { - struct vattr vat; - - error = VOP_GETATTR(vp, &vat, td->td_ucred, td); - if (error) { - vput(vp); - mtx_unlock(&Giant); - return (error); - } - objsize = round_page(vat.va_size); - type = OBJT_VNODE; - /* - * if it is a regular file without any references - * we do not need to sync it. - */ - if (vp->v_type == VREG && vat.va_nlink == 0) { - flags |= MAP_NOSYNC; - } - } } - - if (handle == NULL) { + if (flags & MAP_ANON) { object = NULL; docow = 0; + /* + * Unnamed anonymous regions always start at 0. + */ + if (handle == 0) + foff = 0; } else { - object = vm_pager_allocate(type, - handle, objsize, prot, foff); - if (type == OBJT_VNODE) { - vput(vp); - mtx_unlock(&Giant); - } - if (object == NULL) { - return (type == OBJT_DEVICE ? EINVAL : ENOMEM); - } docow = MAP_PREFAULT_PARTIAL; } - /* - * Force device mappings to be shared. - */ - if (type == OBJT_DEVICE) { - flags &= ~(MAP_PRIVATE|MAP_COPY); - flags |= MAP_SHARED; - } - if ((flags & (MAP_ANON|MAP_SHARED)) == 0) docow |= MAP_COPY_ON_WRITE; if (flags & MAP_NOSYNC) -- 2.45.2