/*
- * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2015 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
*
* @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95
*/
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections. This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
+ */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/mount_internal.h>
#include <sys/vnode_internal.h>
+#include <miscfs/specfs/specdev.h>
#include <sys/namei.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/kauth.h>
#include <sys/user.h>
+#include <sys/paths.h>
+
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif
/*
* Name caching works as follows:
long numcache; /* number of cache entries allocated */
int desiredNodes;
int desiredNegNodes;
+int ncs_negtotal;
+int nc_disabled = 0;
TAILQ_HEAD(, namecache) nchead; /* chain of all name cache entries */
TAILQ_HEAD(, namecache) neghead; /* chain of only negative cache entries */
+
+
+#if COLLECT_STATS
+
struct nchstats nchstats; /* cache effectiveness statistics */
+#define NCHSTAT(v) { \
+ nchstats.v++; \
+}
+#define NAME_CACHE_LOCK() name_cache_lock()
+#define NAME_CACHE_UNLOCK() name_cache_unlock()
+#define NAME_CACHE_LOCK_SHARED() name_cache_lock()
+
+#else
+
+#define NCHSTAT(v)
+#define NAME_CACHE_LOCK() name_cache_lock()
+#define NAME_CACHE_UNLOCK() name_cache_unlock()
+#define NAME_CACHE_LOCK_SHARED() name_cache_lock_shared()
+
+#endif
+
+
/* vars for name cache list lock */
lck_grp_t * namecache_lck_grp;
lck_grp_attr_t * namecache_lck_grp_attr;
lck_attr_t * namecache_lck_attr;
-lck_mtx_t * namecache_mtx_lock;
+
+lck_grp_t * strcache_lck_grp;
+lck_grp_attr_t * strcache_lck_grp_attr;
+lck_attr_t * strcache_lck_attr;
+
+lck_rw_t * namecache_rw_lock;
+lck_rw_t * strtable_rw_lock;
+
+#define NUM_STRCACHE_LOCKS 1024
+
+lck_mtx_t strcache_mtx_locks[NUM_STRCACHE_LOCKS];
+
static vnode_t cache_lookup_locked(vnode_t dvp, struct componentname *cnp);
-static int remove_name_locked(const char *);
-static char *add_name_locked(const char *, size_t, u_int, u_int);
+static const char *add_name_internal(const char *, uint32_t, u_int, boolean_t, u_int);
static void init_string_table(void);
static void cache_delete(struct namecache *, int);
-static void dump_string_table(void);
+static void cache_enter_locked(vnode_t dvp, vnode_t vp, struct componentname *cnp, const char *strname);
+
+#ifdef DUMP_STRING_TABLE
+/*
+ * Internal dump function used for debugging
+ */
+void dump_string_table(void);
+#endif /* DUMP_STRING_TABLE */
static void init_crc32(void);
static unsigned int crc32tab[256];
-//
-// This function builds the path to a filename in "buff". The
-// length of the buffer *INCLUDING* the trailing zero byte is
-// returned in outlen. NOTE: the length includes the trailing
-// zero byte and thus the length is one greater than what strlen
-// would return. This is important and lots of code elsewhere
-// in the kernel assumes this behavior.
-//
+/*
+ * This function builds the path to a filename in "buff". The
+ * length of the buffer *INCLUDING* the trailing zero byte is
+ * returned in outlen. NOTE: the length includes the trailing
+ * zero byte and thus the length is one greater than what strlen
+ * would return. This is important and lots of code elsewhere
+ * in the kernel assumes this behavior.
+ *
+ * This function can call vnop in file system if the parent vnode
+ * does not exist or when called for hardlinks via volfs path.
+ * If BUILDPATH_NO_FS_ENTER is set in flags, it only uses values present
+ * in the name cache and does not enter the file system.
+ *
+ * If BUILDPATH_CHECK_MOVED is set in flags, we return EAGAIN when
+ * we encounter ENOENT during path reconstruction. ENOENT means that
+ * one of the parents moved while we were building the path. The
+ * caller can special handle this case by calling build_path again.
+ *
+ * If BUILDPATH_VOLUME_RELATIVE is set in flags, we return path
+ * that is relative to the nearest mount point, i.e. do not
+ * cross over mount points during building the path.
+ *
+ * passed in vp must have a valid io_count reference
+ */
int
-build_path(vnode_t first_vp, char *buff, int buflen, int *outlen)
+build_path(vnode_t first_vp, char *buff, int buflen, int *outlen, int flags, vfs_context_t ctx)
{
- vnode_t vp = first_vp;
- char *end, *str;
- int len, ret=0, counter=0;
+ vnode_t vp, tvp;
+ vnode_t vp_with_iocount;
+ vnode_t proc_root_dir_vp;
+ char *end;
+ const char *str;
+ int len;
+ int ret = 0;
+ int fixhardlink;
+
+ if (first_vp == NULLVP)
+ return (EINVAL);
+
+ if (buflen <= 1)
+ return (ENOSPC);
+
+ /*
+ * Grab the process fd so we can evaluate fd_rdir.
+ */
+ if (vfs_context_proc(ctx)->p_fd)
+ proc_root_dir_vp = vfs_context_proc(ctx)->p_fd->fd_rdir;
+ else
+ proc_root_dir_vp = NULL;
+
+ vp_with_iocount = NULLVP;
+again:
+ vp = first_vp;
end = &buff[buflen-1];
*end = '\0';
/*
- * if this is the root dir of a file system...
+ * holding the NAME_CACHE_LOCK in shared mode is
+ * sufficient to stabilize both the vp->v_parent chain
+ * and the 'vp->v_mount->mnt_vnodecovered' chain
+ *
+ * if we need to drop this lock, we must first grab the v_id
+ * from the vnode we're currently working with... if that
+ * vnode doesn't already have an io_count reference (the vp
+ * passed in comes with one), we must grab a reference
+ * after we drop the NAME_CACHE_LOCK via vnode_getwithvid...
+ * deadlocks may result if you call vnode_get while holding
+ * the NAME_CACHE_LOCK... we lazily release the reference
+ * we pick up the next time we encounter a need to drop
+ * the NAME_CACHE_LOCK or before we return from this routine
*/
- if (vp && (vp->v_flag & VROOT) && vp->v_mount) {
- /*
- * then if it's the root fs, just put in a '/' and get out of here
- */
- if (vp->v_mount->mnt_flag & MNT_ROOTFS) {
+ NAME_CACHE_LOCK_SHARED();
+
+ /*
+ * Check if this is the root of a file system.
+ */
+ while (vp && vp->v_flag & VROOT) {
+ if (vp->v_mount == NULL) {
+ ret = EINVAL;
+ goto out_unlock;
+ }
+ if ((vp->v_mount->mnt_flag & MNT_ROOTFS) || (vp == proc_root_dir_vp)) {
+ /*
+ * It's the root of the root file system, so it's
+ * just "/".
+ */
*--end = '/';
- goto out;
+
+ goto out_unlock;
} else {
- /*
- * else just use the covered vnode to get the mount path
+ /*
+ * This the root of the volume and the caller does not
+ * want to cross mount points. Therefore just return
+ * '/' as the relative path.
*/
- vp = vp->v_mount->mnt_vnodecovered;
+ if (flags & BUILDPATH_VOLUME_RELATIVE) {
+ *--end = '/';
+ goto out_unlock;
+ } else {
+ vp = vp->v_mount->mnt_vnodecovered;
+ }
}
}
- name_cache_lock();
- while (vp && vp->v_parent != vp) {
- /*
- * the maximum depth of a file system hierarchy is MAXPATHLEN/2
- * (with single-char names separated by slashes). we panic if
- * we've ever looped more than that.
- */
- if (counter++ > MAXPATHLEN/2) {
- panic("build_path: vnode parent chain is too long! vp 0x%x\n", vp);
- }
- str = vp->v_name;
-
- if (str == NULL) {
- if (vp->v_parent != NULL) {
- ret = EINVAL;
- }
- break;
- }
- len = strlen(str);
+ while ((vp != NULLVP) && (vp->v_parent != vp)) {
+ int vid;
/*
- * check that there's enough space (make sure to include space for the '/')
+ * For hardlinks the v_name may be stale, so if its OK
+ * to enter a file system, ask the file system for the
+ * name and parent (below).
*/
- if ((end - buff) < (len + 1)) {
- ret = ENOSPC;
- break;
+ fixhardlink = (vp->v_flag & VISHARDLINK) &&
+ (vp->v_mount->mnt_kern_flag & MNTK_PATH_FROM_ID) &&
+ !(flags & BUILDPATH_NO_FS_ENTER);
+
+ if (!fixhardlink) {
+ str = vp->v_name;
+
+ if (str == NULL || *str == '\0') {
+ if (vp->v_parent != NULL)
+ ret = EINVAL;
+ else
+ ret = ENOENT;
+ goto out_unlock;
+ }
+ len = strlen(str);
+ /*
+ * Check that there's enough space (including space for the '/')
+ */
+ if ((end - buff) < (len + 1)) {
+ ret = ENOSPC;
+ goto out_unlock;
+ }
+ /*
+ * Copy the name backwards.
+ */
+ str += len;
+
+ for (; len > 0; len--)
+ *--end = *--str;
+ /*
+ * Add a path separator.
+ */
+ *--end = '/';
}
+
/*
- * copy it backwards
+ * Walk up the parent chain.
*/
- str += len;
+ if (((vp->v_parent != NULLVP) && !fixhardlink) ||
+ (flags & BUILDPATH_NO_FS_ENTER)) {
+
+ /*
+ * In this if () block we are not allowed to enter the filesystem
+ * to conclusively get the most accurate parent identifier.
+ * As a result, if 'vp' does not identify '/' and it
+ * does not have a valid v_parent, then error out
+ * and disallow further path construction
+ */
+ if ((vp->v_parent == NULLVP) && (rootvnode != vp)) {
+ /*
+ * Only '/' is allowed to have a NULL parent
+ * pointer. Upper level callers should ideally
+ * re-drive name lookup on receiving a ENOENT.
+ */
+ ret = ENOENT;
+
+ /* The code below will exit early if 'tvp = vp' == NULL */
+ }
+ vp = vp->v_parent;
+
+ /*
+ * if the vnode we have in hand isn't a directory and it
+ * has a v_parent, then we started with the resource fork
+ * so skip up to avoid getting a duplicate copy of the
+ * file name in the path.
+ */
+ if (vp && !vnode_isdir(vp) && vp->v_parent) {
+ vp = vp->v_parent;
+ }
+ } else {
+ /*
+ * No parent, go get it if supported.
+ */
+ struct vnode_attr va;
+ vnode_t dvp;
- for (; len > 0; len--) {
- *--end = *--str;
+ /*
+ * Make sure file system supports obtaining a path from id.
+ */
+ if (!(vp->v_mount->mnt_kern_flag & MNTK_PATH_FROM_ID)) {
+ ret = ENOENT;
+ goto out_unlock;
+ }
+ vid = vp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if (vp != first_vp && vp != vp_with_iocount) {
+ if (vp_with_iocount) {
+ vnode_put(vp_with_iocount);
+ vp_with_iocount = NULLVP;
+ }
+ if (vnode_getwithvid(vp, vid))
+ goto again;
+ vp_with_iocount = vp;
+ }
+ VATTR_INIT(&va);
+ VATTR_WANTED(&va, va_parentid);
+
+ if (fixhardlink) {
+ VATTR_WANTED(&va, va_name);
+ MALLOC_ZONE(va.va_name, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+ } else {
+ va.va_name = NULL;
+ }
+ /*
+ * Ask the file system for its parent id and for its name (optional).
+ */
+ ret = vnode_getattr(vp, &va, ctx);
+
+ if (fixhardlink) {
+ if ((ret == 0) && (VATTR_IS_SUPPORTED(&va, va_name))) {
+ str = va.va_name;
+ vnode_update_identity(vp, NULL, str, strlen(str), 0, VNODE_UPDATE_NAME);
+ } else if (vp->v_name) {
+ str = vp->v_name;
+ ret = 0;
+ } else {
+ ret = ENOENT;
+ goto bad_news;
+ }
+ len = strlen(str);
+
+ /*
+ * Check that there's enough space.
+ */
+ if ((end - buff) < (len + 1)) {
+ ret = ENOSPC;
+ } else {
+ /* Copy the name backwards. */
+ str += len;
+
+ for (; len > 0; len--) {
+ *--end = *--str;
+ }
+ /*
+ * Add a path separator.
+ */
+ *--end = '/';
+ }
+bad_news:
+ FREE_ZONE(va.va_name, MAXPATHLEN, M_NAMEI);
+ }
+ if (ret || !VATTR_IS_SUPPORTED(&va, va_parentid)) {
+ ret = ENOENT;
+ goto out;
+ }
+ /*
+ * Ask the file system for the parent vnode.
+ */
+ if ((ret = VFS_VGET(vp->v_mount, (ino64_t)va.va_parentid, &dvp, ctx)))
+ goto out;
+
+ if (!fixhardlink && (vp->v_parent != dvp))
+ vnode_update_identity(vp, dvp, NULL, 0, 0, VNODE_UPDATE_PARENT);
+
+ if (vp_with_iocount)
+ vnode_put(vp_with_iocount);
+ vp = dvp;
+ vp_with_iocount = vp;
+
+ NAME_CACHE_LOCK_SHARED();
+
+ /*
+ * if the vnode we have in hand isn't a directory and it
+ * has a v_parent, then we started with the resource fork
+ * so skip up to avoid getting a duplicate copy of the
+ * file name in the path.
+ */
+ if (vp && !vnode_isdir(vp) && vp->v_parent)
+ vp = vp->v_parent;
}
- /*
- * put in the path separator
- */
- *--end = '/';
/*
- * walk up the chain (as long as we're not the root)
+ * When a mount point is crossed switch the vp.
+ * Continue until we find the root or we find
+ * a vnode that's not the root of a mounted
+ * file system.
*/
- if (vp == first_vp && (vp->v_flag & VROOT)) {
- if (vp->v_mount && vp->v_mount->mnt_vnodecovered) {
- vp = vp->v_mount->mnt_vnodecovered->v_parent;
+ tvp = vp;
+
+ while (tvp) {
+ if (tvp == proc_root_dir_vp)
+ goto out_unlock; /* encountered the root */
+
+ if (!(tvp->v_flag & VROOT) || !tvp->v_mount)
+ break; /* not the root of a mounted FS */
+
+ if (flags & BUILDPATH_VOLUME_RELATIVE) {
+ /* Do not cross over mount points */
+ tvp = NULL;
} else {
- vp = NULLVP;
+ tvp = tvp->v_mount->mnt_vnodecovered;
}
- } else {
- vp = vp->v_parent;
}
- /*
- * check if we're crossing a mount point and
- * switch the vp if we are.
- */
- if (vp && (vp->v_flag & VROOT) && vp->v_mount) {
- vp = vp->v_mount->mnt_vnodecovered;
+ if (tvp == NULLVP)
+ goto out_unlock;
+ vp = tvp;
+
+ if (vp && (flags & BUILDPATH_CHECKACCESS)) {
+ vid = vp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if (vp != first_vp && vp != vp_with_iocount) {
+ if (vp_with_iocount) {
+ vnode_put(vp_with_iocount);
+ vp_with_iocount = NULLVP;
+ }
+ if (vnode_getwithvid(vp, vid))
+ goto again;
+ vp_with_iocount = vp;
+ }
+ if ((ret = vnode_authorize(vp, NULL, KAUTH_VNODE_SEARCH, ctx)))
+ goto out; /* no peeking */
+
+ NAME_CACHE_LOCK_SHARED();
}
}
- name_cache_unlock();
+out_unlock:
+ NAME_CACHE_UNLOCK();
out:
+ if (vp_with_iocount)
+ vnode_put(vp_with_iocount);
/*
- * slide it down to the beginning of the buffer
+ * Slide the name down to the beginning of the buffer.
*/
memmove(buff, end, &buff[buflen] - end);
-
- *outlen = &buff[buflen] - end; // length includes the trailing zero byte
+
+ /*
+ * length includes the trailing zero byte
+ */
+ *outlen = &buff[buflen] - end;
- return ret;
+ /* One of the parents was moved during path reconstruction.
+ * The caller is interested in knowing whether any of the
+ * parents moved via BUILDPATH_CHECK_MOVED, so return EAGAIN.
+ */
+ if ((ret == ENOENT) && (flags & BUILDPATH_CHECK_MOVED)) {
+ ret = EAGAIN;
+ }
+
+ return (ret);
}
vnode_t pvp = NULLVP;
int pvid;
- name_cache_lock();
+ NAME_CACHE_LOCK_SHARED();
/*
* v_parent is stable behind the name_cache lock
* however, the only thing we can really guarantee
if ( (pvp = vp->v_parent) != NULLVP ) {
pvid = pvp->v_id;
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
if (vnode_getwithvid(pvp, pvid) != 0)
pvp = NULL;
} else
- name_cache_unlock();
-
+ NAME_CACHE_UNLOCK();
return (pvp);
}
-char *
+const char *
vnode_getname(vnode_t vp)
{
- char *name = NULL;
-
- name_cache_lock();
+ const char *name = NULL;
+
+ NAME_CACHE_LOCK_SHARED();
if (vp->v_name)
- name = add_name_locked(vp->v_name, strlen(vp->v_name), 0, 0);
- name_cache_unlock();
+ name = vfs_addname(vp->v_name, strlen(vp->v_name), 0, 0);
+ NAME_CACHE_UNLOCK();
return (name);
}
void
-vnode_putname(char *name)
+vnode_putname(const char *name)
{
- name_cache_lock();
+ vfs_removename(name);
+}
- remove_name_locked(name);
+static const char unknown_vnodename[] = "(unknown vnode name)";
- name_cache_unlock();
+const char *
+vnode_getname_printable(vnode_t vp)
+{
+ const char *name = vnode_getname(vp);
+ if (name != NULL)
+ return name;
+
+ switch (vp->v_type) {
+ case VCHR:
+ case VBLK:
+ {
+ /*
+ * Create an artificial dev name from
+ * major and minor device number
+ */
+ char dev_name[64];
+ (void) snprintf(dev_name, sizeof(dev_name),
+ "%c(%u, %u)", VCHR == vp->v_type ? 'c':'b',
+ major(vp->v_rdev), minor(vp->v_rdev));
+ /*
+ * Add the newly created dev name to the name
+ * cache to allow easier cleanup. Also,
+ * vfs_addname allocates memory for the new name
+ * and returns it.
+ */
+ NAME_CACHE_LOCK_SHARED();
+ name = vfs_addname(dev_name, strlen(dev_name), 0, 0);
+ NAME_CACHE_UNLOCK();
+ return name;
+ }
+ default:
+ return unknown_vnodename;
+ }
}
+void
+vnode_putname_printable(const char *name)
+{
+ if (name == unknown_vnodename)
+ return;
+ vnode_putname(name);
+}
+
/*
* if VNODE_UPDATE_PARENT, and we can take
* if VNODE_UPDATE_CACHE, flush the name cache entries associated with vp
*/
void
-vnode_update_identity(vnode_t vp, vnode_t dvp, char *name, int name_len, int name_hashval, int flags)
+vnode_update_identity(vnode_t vp, vnode_t dvp, const char *name, int name_len, uint32_t name_hashval, int flags)
{
struct namecache *ncp;
vnode_t old_parentvp = NULLVP;
-
+#if NAMEDSTREAMS
+ int isstream = (vp->v_flag & VISNAMEDSTREAM);
+ int kusecountbumped = 0;
+#endif
+ kauth_cred_t tcred = NULL;
+ const char *vname = NULL;
+ const char *tname = NULL;
if (flags & VNODE_UPDATE_PARENT) {
- if (dvp && vnode_ref(dvp) != 0)
- dvp = NULLVP;
- } else
+ if (dvp && vnode_ref(dvp) != 0) {
+ dvp = NULLVP;
+ }
+#if NAMEDSTREAMS
+ /* Don't count a stream's parent ref during unmounts */
+ if (isstream && dvp && (dvp != vp) && (dvp != vp->v_parent) && (dvp->v_type == VREG)) {
+ vnode_lock_spin(dvp);
+ ++dvp->v_kusecount;
+ kusecountbumped = 1;
+ vnode_unlock(dvp);
+ }
+#endif
+ } else {
dvp = NULLVP;
- name_cache_lock();
+ }
+ if ( (flags & VNODE_UPDATE_NAME) ) {
+ if (name != vp->v_name) {
+ if (name && *name) {
+ if (name_len == 0)
+ name_len = strlen(name);
+ tname = vfs_addname(name, name_len, name_hashval, 0);
+ }
+ } else
+ flags &= ~VNODE_UPDATE_NAME;
+ }
+ if ( (flags & (VNODE_UPDATE_PURGE | VNODE_UPDATE_PARENT | VNODE_UPDATE_CACHE | VNODE_UPDATE_NAME)) ) {
+
+ NAME_CACHE_LOCK();
+
+ if ( (flags & VNODE_UPDATE_PURGE) ) {
+
+ if (vp->v_parent)
+ vp->v_parent->v_nc_generation++;
- if ( (flags & VNODE_UPDATE_NAME) && (name != vp->v_name) ) {
- if (vp->v_name != NULL) {
- remove_name_locked(vp->v_name);
- vp->v_name = NULL;
+ while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
+ cache_delete(ncp, 1);
+
+ while ( (ncp = LIST_FIRST(&vp->v_ncchildren)) )
+ cache_delete(ncp, 1);
+
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
+ vp->v_authorized_actions = 0;
}
- if (name && *name) {
- if (name_len == 0)
- name_len = strlen(name);
- vp->v_name = add_name_locked(name, name_len, name_hashval, 0);
+ if ( (flags & VNODE_UPDATE_NAME) ) {
+ vname = vp->v_name;
+ vp->v_name = tname;
}
- }
- if (flags & VNODE_UPDATE_PARENT) {
- if (dvp != vp && dvp != vp->v_parent) {
- old_parentvp = vp->v_parent;
- vp->v_parent = dvp;
- dvp = NULLVP;
+ if (flags & VNODE_UPDATE_PARENT) {
+ if (dvp != vp && dvp != vp->v_parent) {
+ old_parentvp = vp->v_parent;
+ vp->v_parent = dvp;
+ dvp = NULLVP;
- if (old_parentvp)
- flags |= VNODE_UPDATE_CACHE;
+ if (old_parentvp)
+ flags |= VNODE_UPDATE_CACHE;
+ }
}
- }
- if (flags & VNODE_UPDATE_CACHE) {
- while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
- cache_delete(ncp, 1);
- }
- name_cache_unlock();
+ if (flags & VNODE_UPDATE_CACHE) {
+ while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
+ cache_delete(ncp, 1);
+ }
+ NAME_CACHE_UNLOCK();
- if (dvp != NULLVP)
+ if (vname != NULL)
+ vfs_removename(vname);
+
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
+ }
+ if (dvp != NULLVP) {
+#if NAMEDSTREAMS
+ /* Back-out the ref we took if we lost a race for vp->v_parent. */
+ if (kusecountbumped) {
+ vnode_lock_spin(dvp);
+ if (dvp->v_kusecount > 0)
+ --dvp->v_kusecount;
+ vnode_unlock(dvp);
+ }
+#endif
vnode_rele(dvp);
-
+ }
if (old_parentvp) {
struct uthread *ut;
+#if NAMEDSTREAMS
+ if (isstream) {
+ vnode_lock_spin(old_parentvp);
+ if ((old_parentvp->v_type != VDIR) && (old_parentvp->v_kusecount > 0))
+ --old_parentvp->v_kusecount;
+ vnode_unlock(old_parentvp);
+ }
+#endif
ut = get_bsdthread_info(current_thread());
/*
while ( (vp = old_parentvp) != NULLVP ) {
- vnode_lock(vp);
-
+ vnode_lock_spin(vp);
vnode_rele_internal(vp, 0, 0, 1);
/*
* we'll sit in this loop until we run into
* a parent in this chain that is not in this state
*
- * make our check and the node_rele atomic
+ * make our check and the vnode_rele atomic
* with respect to the current vnode we're working on
* by holding the vnode lock
* if vnode_rele deferred the vnode_reclaim and has put
* pull the parent pointer now so that when we do the
* vnode_reclaim for each of the vnodes in the uu_vreclaims
* list, we won't recurse back through here
+ *
+ * need to do a convert here in case vnode_rele_internal
+ * returns with the lock held in the spin mode... it
+ * can drop and retake the lock under certain circumstances
*/
- name_cache_lock();
+ vnode_lock_convert(vp);
+
+ NAME_CACHE_LOCK();
old_parentvp = vp->v_parent;
vp->v_parent = NULLVP;
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
} else {
/*
* we're done... we ran into a vnode that isn't
* so that HFS can post-process the lookup. Also, volfs will call
* VNOP_GETATTR2 to determine the parent, instead of using v_parent.
*/
-void vnode_set_hard_link(vnode_t vp)
+void vnode_setmultipath(vnode_t vp)
{
- vnode_lock(vp);
+ vnode_lock_spin(vp);
/*
* In theory, we're changing the vnode's identity as far as the
}
+
+/*
+ * backwards compatibility
+ */
void vnode_uncache_credentials(vnode_t vp)
{
- kauth_cred_t ucred = NULL;
+ vnode_uncache_authorized_action(vp, KAUTH_INVALIDATE_CACHED_RIGHTS);
+}
- if (vp->v_cred) {
- vnode_lock(vp);
- ucred = vp->v_cred;
- vp->v_cred = NULL;
+/*
+ * use the exclusive form of NAME_CACHE_LOCK to protect the update of the
+ * following fields in the vnode: v_cred_timestamp, v_cred, v_authorized_actions
+ * we use this lock so that we can look at the v_cred and v_authorized_actions
+ * atomically while behind the NAME_CACHE_LOCK in shared mode in 'cache_lookup_path',
+ * which is the super-hot path... if we are updating the authorized actions for this
+ * vnode, we are already in the super-slow and far less frequented path so its not
+ * that bad that we take the lock exclusive for this case... of course we strive
+ * to hold it for the minimum amount of time possible
+ */
+
+void vnode_uncache_authorized_action(vnode_t vp, kauth_action_t action)
+{
+ kauth_cred_t tcred = NOCRED;
+
+ NAME_CACHE_LOCK();
- vnode_unlock(vp);
+ vp->v_authorized_actions &= ~action;
- if (ucred)
- kauth_cred_rele(ucred);
+ if (action == KAUTH_INVALIDATE_CACHED_RIGHTS &&
+ IS_VALID_CRED(vp->v_cred)) {
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
}
+ NAME_CACHE_UNLOCK();
+
+ if (tcred != NOCRED)
+ kauth_cred_unref(&tcred);
}
-void vnode_cache_credentials(vnode_t vp, vfs_context_t context)
+extern int bootarg_vnode_cache_defeat; /* default = 0, from bsd_init.c */
+
+boolean_t
+vnode_cache_is_authorized(vnode_t vp, vfs_context_t ctx, kauth_action_t action)
{
- kauth_cred_t ucred;
- kauth_cred_t tcred = NOCRED;
- struct timeval tv;
+ kauth_cred_t ucred;
+ boolean_t retval = FALSE;
- ucred = vfs_context_ucred(context);
+ /* Boot argument to defeat rights caching */
+ if (bootarg_vnode_cache_defeat)
+ return FALSE;
- if (vp->v_cred != ucred || (vp->v_mount->mnt_kern_flag & MNTK_AUTH_OPAQUE)) {
- vnode_lock(vp);
+ if ( (vp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ /*
+ * a TTL is enabled on the rights cache... handle it here
+ * a TTL of 0 indicates that no rights should be cached
+ */
+ if (vp->v_mount->mnt_authcache_ttl) {
+ if ( !(vp->v_mount->mnt_kern_flag & MNTK_AUTH_CACHE_TTL) ) {
+ /*
+ * For filesystems marked only MNTK_AUTH_OPAQUE (generally network ones),
+ * we will only allow a SEARCH right on a directory to be cached...
+ * that cached right always has a default TTL associated with it
+ */
+ if (action != KAUTH_VNODE_SEARCH || vp->v_type != VDIR)
+ vp = NULLVP;
+ }
+ if (vp != NULLVP && vnode_cache_is_stale(vp) == TRUE) {
+ vnode_uncache_authorized_action(vp, vp->v_authorized_actions);
+ vp = NULLVP;
+ }
+ } else
+ vp = NULLVP;
+ }
+ if (vp != NULLVP) {
+ ucred = vfs_context_ucred(ctx);
- microuptime(&tv);
- vp->v_cred_timestamp = tv.tv_sec;
+ NAME_CACHE_LOCK_SHARED();
- if (vp->v_cred != ucred) {
- kauth_cred_ref(ucred);
-
- tcred = vp->v_cred;
- vp->v_cred = ucred;
- }
- vnode_unlock(vp);
-
- if (tcred)
- kauth_cred_rele(tcred);
+ if (vp->v_cred == ucred && (vp->v_authorized_actions & action) == action)
+ retval = TRUE;
+
+ NAME_CACHE_UNLOCK();
}
+ return retval;
}
-/* reverse_lookup - lookup by walking back up the parent chain while leveraging
- * use of the name cache lock in order to protect our starting vnode.
- * NOTE - assumes you already have search access to starting point.
- * returns 0 when we have reached the root, current working dir, or chroot root
- *
- */
-int
-reverse_lookup(vnode_t start_vp, vnode_t *lookup_vpp, struct filedesc *fdp, vfs_context_t context, int *dp_authorized)
+
+void vnode_cache_authorized_action(vnode_t vp, vfs_context_t ctx, kauth_action_t action)
{
- int vid, done = 0;
- int auth_opaque = 0;
- vnode_t dp = start_vp;
- vnode_t vp = NULLVP;
- kauth_cred_t ucred;
- struct timeval tv;
+ kauth_cred_t tcred = NOCRED;
+ kauth_cred_t ucred;
+ struct timeval tv;
+ boolean_t ttl_active = FALSE;
- ucred = vfs_context_ucred(context);
- *lookup_vpp = start_vp;
+ ucred = vfs_context_ucred(ctx);
- name_cache_lock();
+ if (!IS_VALID_CRED(ucred) || action == 0)
+ return;
+
+ if ( (vp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ /*
+ * a TTL is enabled on the rights cache... handle it here
+ * a TTL of 0 indicates that no rights should be cached
+ */
+ if (vp->v_mount->mnt_authcache_ttl == 0)
+ return;
+
+ if ( !(vp->v_mount->mnt_kern_flag & MNTK_AUTH_CACHE_TTL) ) {
+ /*
+ * only cache SEARCH action for filesystems marked
+ * MNTK_AUTH_OPAQUE on VDIRs...
+ * the lookup_path code will time these out
+ */
+ if ( (action & ~KAUTH_VNODE_SEARCH) || vp->v_type != VDIR )
+ return;
+ }
+ ttl_active = TRUE;
- if ( dp->v_mount && (dp->v_mount->mnt_kern_flag & MNTK_AUTH_OPAQUE) ) {
- auth_opaque = 1;
microuptime(&tv);
}
- for (;;) {
- *dp_authorized = 0;
+ NAME_CACHE_LOCK();
- if (auth_opaque && ((tv.tv_sec - dp->v_cred_timestamp) > VCRED_EXPIRED))
- break;
- if (dp->v_cred != ucred)
- break;
- /*
- * indicate that we're allowed to traverse this directory...
- * even if we bail for some reason, this information is valid and is used
- * to avoid doing a vnode_authorize
+ if (vp->v_cred != ucred) {
+ kauth_cred_ref(ucred);
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
*/
- *dp_authorized = 1;
+ tcred = vp->v_cred;
+ vp->v_cred = ucred;
+ vp->v_authorized_actions = 0;
+ }
+ if (ttl_active == TRUE && vp->v_authorized_actions == 0) {
+ /*
+ * only reset the timestamnp on the
+ * first authorization cached after the previous
+ * timer has expired or we're switching creds...
+ * 'vnode_cache_is_authorized' will clear the
+ * authorized actions if the TTL is active and
+ * it has expired
+ */
+ vp->v_cred_timestamp = tv.tv_sec;
+ }
+ vp->v_authorized_actions |= action;
- if ((dp->v_flag & VROOT) != 0 || /* Hit "/" */
- (dp == fdp->fd_cdir) || /* Hit process's working directory */
- (dp == fdp->fd_rdir)) { /* Hit process chroot()-ed root */
- done = 1;
- break;
- }
+ NAME_CACHE_UNLOCK();
- if ( (vp = dp->v_parent) == NULLVP)
- break;
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
+}
- dp = vp;
- *lookup_vpp = dp;
- } /* for (;;) */
- vid = dp->v_id;
-
- name_cache_unlock();
-
- if (done == 0 && dp != start_vp) {
- if (vnode_getwithvid(dp, vid) != 0) {
- *lookup_vpp = start_vp;
- }
- }
+boolean_t vnode_cache_is_stale(vnode_t vp)
+{
+ struct timeval tv;
+ boolean_t retval;
+
+ microuptime(&tv);
- return((done == 1) ? 0 : -1);
+ if ((tv.tv_sec - vp->v_cred_timestamp) > vp->v_mount->mnt_authcache_ttl)
+ retval = TRUE;
+ else
+ retval = FALSE;
+
+ return retval;
}
+
+
+/*
+ * Returns: 0 Success
+ * ERECYCLE vnode was recycled from underneath us. Force lookup to be re-driven from namei.
+ * This errno value should not be seen by anyone outside of the kernel.
+ */
int
-cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp, vfs_context_t context, int *trailing_slash, int *dp_authorized)
+cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
+ vfs_context_t ctx, int *dp_authorized, vnode_t last_dp)
{
char *cp; /* pointer into pathname argument */
- int vid, vvid;
- int auth_opaque = 0;
+ int vid;
+ int vvid = 0; /* protected by vp != NULLVP */
vnode_t vp = NULLVP;
vnode_t tdp = NULLVP;
kauth_cred_t ucred;
- struct timeval tv;
+ boolean_t ttl_enabled = FALSE;
+ struct timeval tv;
+ mount_t mp;
unsigned int hash;
+ int error = 0;
- ucred = vfs_context_ucred(context);
- *trailing_slash = 0;
+#if CONFIG_TRIGGERS
+ vnode_t trigger_vp;
+#endif /* CONFIG_TRIGGERS */
- name_cache_lock();
+ ucred = vfs_context_ucred(ctx);
+ ndp->ni_flag &= ~(NAMEI_TRAILINGSLASH);
+ NAME_CACHE_LOCK_SHARED();
- if ( dp->v_mount && (dp->v_mount->mnt_kern_flag & MNTK_AUTH_OPAQUE) ) {
- auth_opaque = 1;
+ if ( dp->v_mount && (dp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ ttl_enabled = TRUE;
microuptime(&tv);
}
for (;;) {
- /*
+ /*
* Search a directory.
*
* The cn_hash value is for use by cache_lookup
cp = cnp->cn_nameptr;
while (*cp && (*cp != '/')) {
- hash ^= crc32tab[((hash >> 24) ^ (unsigned char)*cp++)];
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
}
/*
* the crc generator can legitimately generate
ndp->ni_pathlen--;
if (*cp == '\0') {
- *trailing_slash = 1;
+ ndp->ni_flag |= NAMEI_TRAILINGSLASH;
*ndp->ni_next = '\0';
}
}
cnp->cn_flags |= ISDOTDOT;
*dp_authorized = 0;
+#if NAMEDRSRCFORK
+ /*
+ * Process a request for a file's resource fork.
+ *
+ * Consume the _PATH_RSRCFORKSPEC suffix and tag the path.
+ */
+ if ((ndp->ni_pathlen == sizeof(_PATH_RSRCFORKSPEC)) &&
+ (cp[1] == '.' && cp[2] == '.') &&
+ bcmp(cp, _PATH_RSRCFORKSPEC, sizeof(_PATH_RSRCFORKSPEC)) == 0) {
+ /* Skip volfs file systems that don't support native streams. */
+ if ((dp->v_mount != NULL) &&
+ (dp->v_mount->mnt_flag & MNT_DOVOLFS) &&
+ (dp->v_mount->mnt_kern_flag & MNTK_NAMED_STREAMS) == 0) {
+ goto skiprsrcfork;
+ }
+ cnp->cn_flags |= CN_WANTSRSRCFORK;
+ cnp->cn_flags |= ISLASTCN;
+ ndp->ni_next[0] = '\0';
+ ndp->ni_pathlen = 1;
+ }
+skiprsrcfork:
+#endif
+
+#if CONFIG_MACF
- if (auth_opaque && ((tv.tv_sec - dp->v_cred_timestamp) > VCRED_EXPIRED))
+ /*
+ * Name cache provides authorization caching (see below)
+ * that will short circuit MAC checks in lookup().
+ * We must perform MAC check here. On denial
+ * dp_authorized will remain 0 and second check will
+ * be perfomed in lookup().
+ */
+ if (!(cnp->cn_flags & DONOTAUTH)) {
+ error = mac_vnode_check_lookup(ctx, dp, cnp);
+ if (error) {
+ NAME_CACHE_UNLOCK();
+ goto errorout;
+ }
+ }
+#endif /* MAC */
+ if (ttl_enabled && ((tv.tv_sec - dp->v_cred_timestamp) > dp->v_mount->mnt_authcache_ttl))
break;
- if (dp->v_cred != ucred)
+ /*
+ * NAME_CACHE_LOCK holds these fields stable
+ */
+ if ((dp->v_cred != ucred || !(dp->v_authorized_actions & KAUTH_VNODE_SEARCH)) &&
+ !(dp->v_authorized_actions & KAUTH_VNODE_SEARCHBYANYONE))
break;
+
/*
* indicate that we're allowed to traverse this directory...
* even if we fail the cache lookup or decide to bail for
*dp_authorized = 1;
if ( (cnp->cn_flags & (ISLASTCN | ISDOTDOT)) ) {
- if (cnp->cn_nameiop != LOOKUP)
- break;
- if (cnp->cn_flags & (LOCKPARENT | NOCACHE))
- break;
+ if (cnp->cn_nameiop != LOOKUP)
+ break;
+ if (cnp->cn_flags & LOCKPARENT)
+ break;
+ if (cnp->cn_flags & NOCACHE)
+ break;
if (cnp->cn_flags & ISDOTDOT) {
+ /*
+ * Force directory hardlinks to go to
+ * file system for ".." requests.
+ */
+ if (dp && (dp->v_flag & VISHARDLINK)) {
+ break;
+ }
/*
* Quit here only if we can't use
* the parent directory pointer or
* don't have one. Otherwise, we'll
* use it below.
*/
- if ((dp->v_flag & VROOT) ||
+ if ((dp->v_flag & VROOT) ||
+ dp == ndp->ni_rootdir ||
dp->v_parent == NULLVP)
break;
}
}
+ if ((cnp->cn_flags & CN_SKIPNAMECACHE)) {
+ /*
+ * Force lookup to go to the filesystem with
+ * all cnp fields set up.
+ */
+ break;
+ }
+
/*
* "." and ".." aren't supposed to be cached, so check
* for them before checking the cache.
*/
if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.')
vp = dp;
- else if (cnp->cn_flags & ISDOTDOT)
+ else if ( (cnp->cn_flags & ISDOTDOT) )
vp = dp->v_parent;
else {
if ( (vp = cache_lookup_locked(dp, cnp)) == NULLVP)
break;
- }
+ if ( (vp->v_flag & VISHARDLINK) ) {
+ /*
+ * The file system wants a VNOP_LOOKUP on this vnode
+ */
+ vp = NULL;
+ break;
+ }
+ }
if ( (cnp->cn_flags & ISLASTCN) )
break;
vp = NULL;
break;
}
- if (vp->v_mountedhere && ((cnp->cn_flags & NOCROSSMOUNT) == 0))
- break;
+
+ if ( (mp = vp->v_mountedhere) && ((cnp->cn_flags & NOCROSSMOUNT) == 0)) {
+ vnode_t tmp_vp = mp->mnt_realrootvp;
+ if (tmp_vp == NULLVP || mp->mnt_generation != mount_generation ||
+ mp->mnt_realrootvp_vid != tmp_vp->v_id)
+ break;
+ vp = tmp_vp;
+ }
+
+#if CONFIG_TRIGGERS
+ /*
+ * After traversing all mountpoints stacked here, if we have a
+ * trigger in hand, resolve it. Note that we don't need to
+ * leave the fast path if the mount has already happened.
+ */
+ if (vp->v_resolve)
+ break;
+#endif /* CONFIG_TRIGGERS */
+
dp = vp;
vp = NULLVP;
vvid = vp->v_id;
vid = dp->v_id;
- name_cache_unlock();
-
+ NAME_CACHE_UNLOCK();
if ((vp != NULLVP) && (vp->v_type != VLNK) &&
((cnp->cn_flags & (ISLASTCN | LOCKPARENT | WANTPARENT | SAVESTART)) == ISLASTCN)) {
dp = NULLVP;
} else {
need_dp:
- /*
+ /*
* return the last directory we looked at
- * with an io reference held
+ * with an io reference held. If it was the one passed
+ * in as a result of the last iteration of VNOP_LOOKUP,
+ * it should already hold an io ref. No need to increase ref.
*/
- if (dp == ndp->ni_usedvp) {
- /*
- * if this vnode matches the one passed in via USEDVP
- * than this context already holds an io_count... just
- * use vnode_get to get an extra ref for lookup to play
- * with... can't use the getwithvid variant here because
- * it will block behind a vnode_drain which would result
- * in a deadlock (since we already own an io_count that the
- * vnode_drain is waiting on)... vnode_get grabs the io_count
- * immediately w/o waiting... it always succeeds
- */
- vnode_get(dp);
- } else if ( (vnode_getwithvid(dp, vid)) ) {
- /*
- * failure indicates the vnode
- * changed identity or is being
- * TERMINATED... in either case
- * punt this lookup
- */
- return (ENOENT);
+ if (last_dp != dp){
+
+ if (dp == ndp->ni_usedvp) {
+ /*
+ * if this vnode matches the one passed in via USEDVP
+ * than this context already holds an io_count... just
+ * use vnode_get to get an extra ref for lookup to play
+ * with... can't use the getwithvid variant here because
+ * it will block behind a vnode_drain which would result
+ * in a deadlock (since we already own an io_count that the
+ * vnode_drain is waiting on)... vnode_get grabs the io_count
+ * immediately w/o waiting... it always succeeds
+ */
+ vnode_get(dp);
+ } else if ((error = vnode_getwithvid_drainok(dp, vid))) {
+ /*
+ * failure indicates the vnode
+ * changed identity or is being
+ * TERMINATED... in either case
+ * punt this lookup.
+ *
+ * don't necessarily return ENOENT, though, because
+ * we really want to go back to disk and make sure it's
+ * there or not if someone else is changing this
+ * vnode. That being said, the one case where we do want
+ * to return ENOENT is when the vnode's mount point is
+ * in the process of unmounting and we might cause a deadlock
+ * in our attempt to take an iocount. An ENODEV error return
+ * is from vnode_get* is an indication this but we change that
+ * ENOENT for upper layers.
+ */
+ if (error == ENODEV) {
+ error = ENOENT;
+ } else {
+ error = ERECYCLE;
+ }
+ goto errorout;
+ }
}
}
if (vp != NULLVP) {
- if ( (vnode_getwithvid(vp, vvid)) ) {
+ if ( (vnode_getwithvid_drainok(vp, vvid)) ) {
vp = NULLVP;
/*
}
}
}
+
ndp->ni_dvp = dp;
ndp->ni_vp = vp;
- return (0);
+#if CONFIG_TRIGGERS
+ trigger_vp = vp ? vp : dp;
+ if ((error == 0) && (trigger_vp != NULLVP) && vnode_isdir(trigger_vp)) {
+ error = vnode_trigger_resolve(trigger_vp, ndp, ctx);
+ if (error) {
+ if (vp)
+ vnode_put(vp);
+ if (dp)
+ vnode_put(dp);
+ goto errorout;
+ }
+ }
+#endif /* CONFIG_TRIGGERS */
+
+errorout:
+ /*
+ * If we came into cache_lookup_path after an iteration of the lookup loop that
+ * resulted in a call to VNOP_LOOKUP, then VNOP_LOOKUP returned a vnode with a io ref
+ * on it. It is now the job of cache_lookup_path to drop the ref on this vnode
+ * when it is no longer needed. If we get to this point, and last_dp is not NULL
+ * and it is ALSO not the dvp we want to return to caller of this function, it MUST be
+ * the case that we got to a subsequent path component and this previous vnode is
+ * no longer needed. We can then drop the io ref on it.
+ */
+ if ((last_dp != NULLVP) && (last_dp != ndp->ni_dvp)){
+ vnode_put(last_dp);
+ }
+
+ //initialized to 0, should be the same if no error cases occurred.
+ return error;
}
static vnode_t
cache_lookup_locked(vnode_t dvp, struct componentname *cnp)
{
- register struct namecache *ncp;
- register struct nchashhead *ncpp;
- register long namelen = cnp->cn_namelen;
- char *nameptr = cnp->cn_nameptr;
- unsigned int hashval = (cnp->cn_hash & NCHASHMASK);
- vnode_t vp;
+ struct namecache *ncp;
+ struct nchashhead *ncpp;
+ long namelen = cnp->cn_namelen;
+ unsigned int hashval = cnp->cn_hash;
+ if (nc_disabled) {
+ return NULL;
+ }
+
ncpp = NCHHASH(dvp, cnp->cn_hash);
LIST_FOREACH(ncp, ncpp, nc_hash) {
if ((ncp->nc_dvp == dvp) && (ncp->nc_hashval == hashval)) {
- if (memcmp(ncp->nc_name, nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
+ if (memcmp(ncp->nc_name, cnp->cn_nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
break;
}
}
- if (ncp == 0)
+ if (ncp == 0) {
/*
* We failed to find an entry
*/
+ NCHSTAT(ncs_miss);
return (NULL);
-
- vp = ncp->nc_vp;
- if (vp && (vp->v_flag & VISHARDLINK)) {
- /*
- * The file system wants a VNOP_LOOKUP on this vnode
- */
- vp = NULL;
}
-
- return (vp);
+ NCHSTAT(ncs_goodhits);
+
+ return (ncp->nc_vp);
}
+unsigned int hash_string(const char *cp, int len);
//
// Have to take a len argument because we may only need to
// hash part of a componentname.
//
-static unsigned int
+unsigned int
hash_string(const char *cp, int len)
{
unsigned hash = 0;
if (len) {
while (len--) {
- hash ^= crc32tab[((hash >> 24) ^ (unsigned char)*cp++)];
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
}
} else {
while (*cp != '\0') {
- hash ^= crc32tab[((hash >> 24) ^ (unsigned char)*cp++)];
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
}
}
/*
*/
int
-cache_lookup(dvp, vpp, cnp)
- struct vnode *dvp;
- struct vnode **vpp;
- struct componentname *cnp;
+cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
{
- register struct namecache *ncp;
- register struct nchashhead *ncpp;
- register long namelen = cnp->cn_namelen;
- char *nameptr = cnp->cn_nameptr;
- unsigned int hashval = (cnp->cn_hash & NCHASHMASK);
+ struct namecache *ncp;
+ struct nchashhead *ncpp;
+ long namelen = cnp->cn_namelen;
+ unsigned int hashval;
+ boolean_t have_exclusive = FALSE;
uint32_t vid;
vnode_t vp;
- name_cache_lock();
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+ hashval = cnp->cn_hash;
+
+ if (nc_disabled) {
+ return 0;
+ }
+
+ NAME_CACHE_LOCK_SHARED();
+relook:
ncpp = NCHHASH(dvp, cnp->cn_hash);
LIST_FOREACH(ncp, ncpp, nc_hash) {
if ((ncp->nc_dvp == dvp) && (ncp->nc_hashval == hashval)) {
- if (memcmp(ncp->nc_name, nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
+ if (memcmp(ncp->nc_name, cnp->cn_nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
break;
}
}
/* We failed to find an entry */
if (ncp == 0) {
- nchstats.ncs_miss++;
- name_cache_unlock();
+ NCHSTAT(ncs_miss);
+ NAME_CACHE_UNLOCK();
return (0);
}
/* We don't want to have an entry, so dump it */
if ((cnp->cn_flags & MAKEENTRY) == 0) {
- nchstats.ncs_badhits++;
- cache_delete(ncp, 1);
- name_cache_unlock();
- return (0);
+ if (have_exclusive == TRUE) {
+ NCHSTAT(ncs_badhits);
+ cache_delete(ncp, 1);
+ NAME_CACHE_UNLOCK();
+ return (0);
+ }
+ NAME_CACHE_UNLOCK();
+ NAME_CACHE_LOCK();
+ have_exclusive = TRUE;
+ goto relook;
}
vp = ncp->nc_vp;
/* We found a "positive" match, return the vnode */
if (vp) {
- nchstats.ncs_goodhits++;
+ NCHSTAT(ncs_goodhits);
vid = vp->v_id;
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
if (vnode_getwithvid(vp, vid)) {
- name_cache_lock();
- nchstats.ncs_badvid++;
- name_cache_unlock();
+#if COLLECT_STATS
+ NAME_CACHE_LOCK();
+ NCHSTAT(ncs_badvid);
+ NAME_CACHE_UNLOCK();
+#endif
return (0);
}
*vpp = vp;
/* We found a negative match, and want to create it, so purge */
if (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME) {
- nchstats.ncs_badhits++;
- cache_delete(ncp, 1);
- name_cache_unlock();
- return (0);
+ if (have_exclusive == TRUE) {
+ NCHSTAT(ncs_badhits);
+ cache_delete(ncp, 1);
+ NAME_CACHE_UNLOCK();
+ return (0);
+ }
+ NAME_CACHE_UNLOCK();
+ NAME_CACHE_LOCK();
+ have_exclusive = TRUE;
+ goto relook;
}
/*
* We found a "negative" match, ENOENT notifies client of this match.
- * The nc_whiteout field records whether this is a whiteout.
*/
- nchstats.ncs_neghits++;
+ NCHSTAT(ncs_neghits);
- if (ncp->nc_whiteout)
- cnp->cn_flags |= ISWHITEOUT;
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
return (ENOENT);
}
+const char *
+cache_enter_create(vnode_t dvp, vnode_t vp, struct componentname *cnp)
+{
+ const char *strname;
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+
+ /*
+ * grab 2 references on the string entered
+ * one for the cache_enter_locked to consume
+ * and the second to be consumed by v_name (vnode_create call point)
+ */
+ strname = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, TRUE, 0);
+
+ NAME_CACHE_LOCK();
+
+ cache_enter_locked(dvp, vp, cnp, strname);
+
+ NAME_CACHE_UNLOCK();
+
+ return (strname);
+}
+
+
+/*
+ * Add an entry to the cache...
+ * but first check to see if the directory
+ * that this entry is to be associated with has
+ * had any cache_purges applied since we took
+ * our identity snapshot... this check needs to
+ * be done behind the name cache lock
+ */
+void
+cache_enter_with_gen(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, int gen)
+{
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+
+ NAME_CACHE_LOCK();
+
+ if (dvp->v_nc_generation == gen)
+ (void)cache_enter_locked(dvp, vp, cnp, NULL);
+
+ NAME_CACHE_UNLOCK();
+}
+
+
/*
* Add an entry to the cache.
*/
void
-cache_enter(dvp, vp, cnp)
- struct vnode *dvp;
- struct vnode *vp;
- struct componentname *cnp;
+cache_enter(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
{
- register struct namecache *ncp, *negp;
- register struct nchashhead *ncpp;
+ const char *strname;
if (cnp->cn_hash == 0)
cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
- name_cache_lock();
+ /*
+ * grab 1 reference on the string entered
+ * for the cache_enter_locked to consume
+ */
+ strname = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, FALSE, 0);
+
+ NAME_CACHE_LOCK();
+
+ cache_enter_locked(dvp, vp, cnp, strname);
+
+ NAME_CACHE_UNLOCK();
+}
- /* if the entry is for -ve caching vp is null */
+
+static void
+cache_enter_locked(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, const char *strname)
+{
+ struct namecache *ncp, *negp;
+ struct nchashhead *ncpp;
+
+ if (nc_disabled)
+ return;
+
+ /*
+ * if the entry is for -ve caching vp is null
+ */
if ((vp != NULLVP) && (LIST_FIRST(&vp->v_nclinks))) {
/*
* someone beat us to the punch..
* this vnode is already in the cache
*/
- name_cache_unlock();
- return;
+ if (strname != NULL)
+ vfs_removename(strname);
+ return;
}
/*
* We allocate a new entry if we are less than the maximum
/*
* Allocate one more entry
*/
- ncp = (struct namecache *)_MALLOC_ZONE((u_long)sizeof *ncp, M_CACHE, M_WAITOK);
+ ncp = (struct namecache *)_MALLOC_ZONE(sizeof(*ncp), M_CACHE, M_WAITOK);
numcache++;
} else {
/*
* still in use... we need to
* delete it before re-using it
*/
- nchstats.ncs_stolen++;
+ NCHSTAT(ncs_stolen);
cache_delete(ncp, 0);
}
}
- nchstats.ncs_enters++;
+ NCHSTAT(ncs_enters);
/*
* Fill in cache info, if vp is NULL this is a "negative" cache entry.
ncp->nc_vp = vp;
ncp->nc_dvp = dvp;
ncp->nc_hashval = cnp->cn_hash;
- ncp->nc_whiteout = FALSE;
- ncp->nc_name = add_name_locked(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, 0);
+
+ if (strname == NULL)
+ ncp->nc_name = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, FALSE, 0);
+ else
+ ncp->nc_name = strname;
+
+ //
+ // If the bytes of the name associated with the vnode differ,
+ // use the name associated with the vnode since the file system
+ // may have set that explicitly in the case of a lookup on a
+ // case-insensitive file system where the case of the looked up
+ // name differs from what is on disk. For more details, see:
+ // <rdar://problem/8044697> FSEvents doesn't always decompose diacritical unicode chars in the paths of the changed directories
+ //
+ const char *vn_name = vp ? vp->v_name : NULL;
+ unsigned int len = vn_name ? strlen(vn_name) : 0;
+ if (vn_name && ncp && ncp->nc_name && strncmp(ncp->nc_name, vn_name, len) != 0) {
+ unsigned int hash = hash_string(vn_name, len);
+
+ vfs_removename(ncp->nc_name);
+ ncp->nc_name = add_name_internal(vn_name, len, hash, FALSE, 0);
+ ncp->nc_hashval = hash;
+ }
/*
* make us the newest entry in the cache
ncpp = NCHHASH(dvp, cnp->cn_hash);
#if DIAGNOSTIC
{
- register struct namecache *p;
+ struct namecache *p;
for (p = ncpp->lh_first; p != 0; p = p->nc_hash.le_next)
if (p == ncp)
} else {
/*
* this is a negative cache entry (vp == NULL)
- * stick it on the negative cache list
- * and record the whiteout state
+ * stick it on the negative cache list.
*/
TAILQ_INSERT_TAIL(&neghead, ncp, nc_un.nc_negentry);
- if (cnp->cn_flags & ISWHITEOUT)
- ncp->nc_whiteout = TRUE;
- nchstats.ncs_negtotal++;
+ ncs_negtotal++;
- if (nchstats.ncs_negtotal > desiredNegNodes) {
+ if (ncs_negtotal > desiredNegNodes) {
/*
* if we've reached our desired limit
* of negative cache entries, delete
* the oldest
*/
negp = TAILQ_FIRST(&neghead);
- TAILQ_REMOVE(&neghead, negp, nc_un.nc_negentry);
-
cache_delete(negp, 1);
}
}
* are children of dvp
*/
LIST_INSERT_HEAD(&dvp->v_ncchildren, ncp, nc_child);
-
- name_cache_unlock();
}
void
nchinit(void)
{
+ int i;
+
desiredNegNodes = (desiredvnodes / 10);
desiredNodes = desiredvnodes + desiredNegNodes;
init_crc32();
- nchashtbl = hashinit(MAX(4096, (2 *desiredNodes)), M_CACHE, &nchash);
+ nchashtbl = hashinit(MAX(CONFIG_NC_HASH, (2 *desiredNodes)), M_CACHE, &nchash);
nchashmask = nchash;
nchash++;
init_string_table();
- /* Allocate mount list lock group attribute and group */
+ /* Allocate name cache lock group attribute and group */
namecache_lck_grp_attr= lck_grp_attr_alloc_init();
- lck_grp_attr_setstat(namecache_lck_grp_attr);
namecache_lck_grp = lck_grp_alloc_init("Name Cache", namecache_lck_grp_attr);
- /* Allocate mount list lock attribute */
+ /* Allocate name cache lock attribute */
namecache_lck_attr = lck_attr_alloc_init();
- //lck_attr_setdebug(namecache_lck_attr);
- /* Allocate mount list lock */
- namecache_mtx_lock = lck_mtx_alloc_init(namecache_lck_grp, namecache_lck_attr);
+ /* Allocate name cache lock */
+ namecache_rw_lock = lck_rw_alloc_init(namecache_lck_grp, namecache_lck_attr);
+ /* Allocate string cache lock group attribute and group */
+ strcache_lck_grp_attr= lck_grp_attr_alloc_init();
+
+ strcache_lck_grp = lck_grp_alloc_init("String Cache", strcache_lck_grp_attr);
+
+ /* Allocate string cache lock attribute */
+ strcache_lck_attr = lck_attr_alloc_init();
+
+ /* Allocate string cache lock */
+ strtable_rw_lock = lck_rw_alloc_init(strcache_lck_grp, strcache_lck_attr);
+
+ for (i = 0; i < NUM_STRCACHE_LOCKS; i++)
+ lck_mtx_init(&strcache_mtx_locks[i], strcache_lck_grp, strcache_lck_attr);
+}
+
+void
+name_cache_lock_shared(void)
+{
+ lck_rw_lock_shared(namecache_rw_lock);
}
void
name_cache_lock(void)
{
- lck_mtx_lock(namecache_mtx_lock);
+ lck_rw_lock_exclusive(namecache_rw_lock);
}
void
name_cache_unlock(void)
{
- lck_mtx_unlock(namecache_mtx_lock);
-
+ lck_rw_done(namecache_rw_lock);
}
dNodes = newsize + dNegNodes;
// we don't support shrinking yet
- if (dNodes < desiredNodes) {
+ if (dNodes <= desiredNodes) {
return 0;
}
new_table = hashinit(2 * dNodes, M_CACHE, &nchashmask);
return ENOMEM;
}
- name_cache_lock();
+ NAME_CACHE_LOCK();
// do the switch!
old_table = nchashtbl;
nchashtbl = new_table;
desiredNodes = dNodes;
desiredNegNodes = dNegNodes;
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
FREE(old_table, M_CACHE);
return 0;
static void
cache_delete(struct namecache *ncp, int age_entry)
{
- nchstats.ncs_deletes++;
+ NCHSTAT(ncs_deletes);
if (ncp->nc_vp) {
LIST_REMOVE(ncp, nc_un.nc_link);
} else {
TAILQ_REMOVE(&neghead, ncp, nc_un.nc_negentry);
- nchstats.ncs_negtotal--;
+ ncs_negtotal--;
}
LIST_REMOVE(ncp, nc_child);
TAILQ_REMOVE(&nchead, ncp, nc_entry);
TAILQ_INSERT_HEAD(&nchead, ncp, nc_entry);
}
- remove_name_locked(ncp->nc_name);
+ vfs_removename(ncp->nc_name);
ncp->nc_name = NULL;
}
cache_purge(vnode_t vp)
{
struct namecache *ncp;
+ kauth_cred_t tcred = NULL;
- if ((LIST_FIRST(&vp->v_nclinks) == NULL) && (LIST_FIRST(&vp->v_ncchildren) == NULL))
+ if ((LIST_FIRST(&vp->v_nclinks) == NULL) &&
+ (LIST_FIRST(&vp->v_ncchildren) == NULL) &&
+ (vp->v_cred == NOCRED) &&
+ (vp->v_parent == NULLVP))
return;
- name_cache_lock();
+ NAME_CACHE_LOCK();
+
+ if (vp->v_parent)
+ vp->v_parent->v_nc_generation++;
while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
cache_delete(ncp, 1);
while ( (ncp = LIST_FIRST(&vp->v_ncchildren)) )
cache_delete(ncp, 1);
- name_cache_unlock();
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
+ vp->v_authorized_actions = 0;
+
+ NAME_CACHE_UNLOCK();
+
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
}
/*
void
cache_purge_negatives(vnode_t vp)
{
- struct namecache *ncp;
+ struct namecache *ncp, *next_ncp;
- name_cache_lock();
+ NAME_CACHE_LOCK();
- LIST_FOREACH(ncp, &vp->v_ncchildren, nc_child)
+ LIST_FOREACH_SAFE(ncp, &vp->v_ncchildren, nc_child, next_ncp)
if (ncp->nc_vp == NULL)
cache_delete(ncp , 1);
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
}
/*
* entries at the same time.
*/
void
-cache_purgevfs(mp)
- struct mount *mp;
+cache_purgevfs(struct mount *mp)
{
struct nchashhead *ncpp;
struct namecache *ncp;
- name_cache_lock();
+ NAME_CACHE_LOCK();
/* Scan hash tables for applicable entries */
for (ncpp = &nchashtbl[nchash - 1]; ncpp >= nchashtbl; ncpp--) {
restart:
}
}
}
- name_cache_unlock();
+ NAME_CACHE_UNLOCK();
}
//
static LIST_HEAD(stringhead, string_t) *string_ref_table;
static u_long string_table_mask;
-static uint32_t max_chain_len=0;
-static struct stringhead *long_chain_head=NULL;
static uint32_t filled_buckets=0;
-static uint32_t num_dups=0;
-static uint32_t nstrings=0;
+
typedef struct string_t {
LIST_ENTRY(string_t) hash_chain;
- unsigned char *str;
+ const char *str;
uint32_t refcount;
} string_t;
-
-static int
+static void
resize_string_ref_table(void)
{
- struct stringhead *new_table;
- struct stringhead *old_table;
- struct stringhead *old_head, *head;
- string_t *entry, *next;
- uint32_t i, hashval;
- u_long new_mask, old_mask;
-
- new_table = hashinit((string_table_mask + 1) * 2, M_CACHE, &new_mask);
- if (new_table == NULL) {
- return ENOMEM;
- }
+ struct stringhead *new_table;
+ struct stringhead *old_table;
+ struct stringhead *old_head, *head;
+ string_t *entry, *next;
+ uint32_t i, hashval;
+ u_long new_mask, old_mask;
- // do the switch!
- old_table = string_ref_table;
- string_ref_table = new_table;
- old_mask = string_table_mask;
- string_table_mask = new_mask;
+ /*
+ * need to hold the table lock exclusively
+ * in order to grow the table... need to recheck
+ * the need to resize again after we've taken
+ * the lock exclusively in case some other thread
+ * beat us to the punch
+ */
+ lck_rw_lock_exclusive(strtable_rw_lock);
- printf("resize: max chain len %d, new table size %d\n",
- max_chain_len, new_mask + 1);
- max_chain_len = 0;
- long_chain_head = NULL;
- filled_buckets = 0;
+ if (4 * filled_buckets < ((string_table_mask + 1) * 3)) {
+ lck_rw_done(strtable_rw_lock);
+ return;
+ }
+ new_table = hashinit((string_table_mask + 1) * 2, M_CACHE, &new_mask);
- // walk the old table and insert all the entries into
- // the new table
- //
- for(i=0; i <= old_mask; i++) {
- old_head = &old_table[i];
- for (entry=old_head->lh_first; entry != NULL; entry=next) {
- hashval = hash_string(entry->str, 0);
- head = &string_ref_table[hashval & string_table_mask];
- if (head->lh_first == NULL) {
- filled_buckets++;
- }
+ if (new_table == NULL) {
+ printf("failed to resize the hash table.\n");
+ lck_rw_done(strtable_rw_lock);
+ return;
+ }
+
+ // do the switch!
+ old_table = string_ref_table;
+ string_ref_table = new_table;
+ old_mask = string_table_mask;
+ string_table_mask = new_mask;
+ filled_buckets = 0;
- next = entry->hash_chain.le_next;
- LIST_INSERT_HEAD(head, entry, hash_chain);
+ // walk the old table and insert all the entries into
+ // the new table
+ //
+ for (i = 0; i <= old_mask; i++) {
+ old_head = &old_table[i];
+ for (entry = old_head->lh_first; entry != NULL; entry = next) {
+ hashval = hash_string((const char *)entry->str, 0);
+ head = &string_ref_table[hashval & string_table_mask];
+ if (head->lh_first == NULL) {
+ filled_buckets++;
+ }
+ next = entry->hash_chain.le_next;
+ LIST_INSERT_HEAD(head, entry, hash_chain);
+ }
}
- }
-
- FREE(old_table, M_CACHE);
+ lck_rw_done(strtable_rw_lock);
- return 0;
+ FREE(old_table, M_CACHE);
}
static void
init_string_table(void)
{
- string_ref_table = hashinit(4096, M_CACHE, &string_table_mask);
+ string_ref_table = hashinit(CONFIG_VFS_NAMES, M_CACHE, &string_table_mask);
}
-char *
-vfs_addname(const char *name, size_t len, u_int hashval, u_int flags)
+const char *
+vfs_addname(const char *name, uint32_t len, u_int hashval, u_int flags)
{
- char * ptr;
-
- name_cache_lock();
- ptr = add_name_locked(name, len, hashval, flags);
- name_cache_unlock();
-
- return(ptr);
+ return (add_name_internal(name, len, hashval, FALSE, flags));
}
-static char *
-add_name_locked(const char *name, size_t len, u_int hashval, __unused u_int flags)
+
+static const char *
+add_name_internal(const char *name, uint32_t len, u_int hashval, boolean_t need_extra_ref, __unused u_int flags)
{
- struct stringhead *head;
- string_t *entry;
- uint32_t chain_len = 0;
+ struct stringhead *head;
+ string_t *entry;
+ uint32_t chain_len = 0;
+ uint32_t hash_index;
+ uint32_t lock_index;
+ char *ptr;
- //
- // If the table gets more than 3/4 full, resize it
- //
- if (4*filled_buckets >= ((string_table_mask + 1) * 3)) {
- if (resize_string_ref_table() != 0) {
- printf("failed to resize the hash table.\n");
- }
- }
- if (hashval == 0) {
- hashval = hash_string(name, 0);
- }
-
- head = &string_ref_table[hashval & string_table_mask];
- for (entry=head->lh_first; entry != NULL; chain_len++, entry=entry->hash_chain.le_next) {
- if (memcmp(entry->str, name, len) == 0 && entry->str[len] == '\0') {
- entry->refcount++;
- num_dups++;
- break;
+ /*
+ * if the length already accounts for the null-byte, then
+ * subtract one so later on we don't index past the end
+ * of the string.
+ */
+ if (len > 0 && name[len-1] == '\0') {
+ len--;
+ }
+ if (hashval == 0) {
+ hashval = hash_string(name, len);
}
- }
- if (entry == NULL) {
- // it wasn't already there so add it.
- MALLOC(entry, string_t *, sizeof(string_t) + len + 1, M_TEMP, M_WAITOK);
+ /*
+ * take this lock 'shared' to keep the hash stable
+ * if someone else decides to grow the pool they
+ * will take this lock exclusively
+ */
+ lck_rw_lock_shared(strtable_rw_lock);
- // have to get "head" again because we could have blocked
- // in malloc and thus head could have changed.
- //
- head = &string_ref_table[hashval & string_table_mask];
- if (head->lh_first == NULL) {
- filled_buckets++;
+ /*
+ * If the table gets more than 3/4 full, resize it
+ */
+ if (4 * filled_buckets >= ((string_table_mask + 1) * 3)) {
+ lck_rw_done(strtable_rw_lock);
+
+ resize_string_ref_table();
+
+ lck_rw_lock_shared(strtable_rw_lock);
}
+ hash_index = hashval & string_table_mask;
+ lock_index = hash_index % NUM_STRCACHE_LOCKS;
+
+ head = &string_ref_table[hash_index];
- entry->str = (char *)((char *)entry + sizeof(string_t));
- strncpy(entry->str, name, len);
- entry->str[len] = '\0';
- entry->refcount = 1;
- LIST_INSERT_HEAD(head, entry, hash_chain);
+ lck_mtx_lock_spin(&strcache_mtx_locks[lock_index]);
- if (chain_len > max_chain_len) {
- max_chain_len = chain_len;
- long_chain_head = head;
+ for (entry = head->lh_first; entry != NULL; chain_len++, entry = entry->hash_chain.le_next) {
+ if (memcmp(entry->str, name, len) == 0 && entry->str[len] == 0) {
+ entry->refcount++;
+ break;
+ }
}
+ if (entry == NULL) {
+ lck_mtx_convert_spin(&strcache_mtx_locks[lock_index]);
+ /*
+ * it wasn't already there so add it.
+ */
+ MALLOC(entry, string_t *, sizeof(string_t) + len + 1, M_TEMP, M_WAITOK);
- nstrings++;
- }
+ if (head->lh_first == NULL) {
+ OSAddAtomic(1, &filled_buckets);
+ }
+ ptr = (char *)((char *)entry + sizeof(string_t));
+ strncpy(ptr, name, len);
+ ptr[len] = '\0';
+ entry->str = ptr;
+ entry->refcount = 1;
+ LIST_INSERT_HEAD(head, entry, hash_chain);
+ }
+ if (need_extra_ref == TRUE)
+ entry->refcount++;
- return entry->str;
+ lck_mtx_unlock(&strcache_mtx_locks[lock_index]);
+ lck_rw_done(strtable_rw_lock);
+
+ return (const char *)entry->str;
}
+
int
vfs_removename(const char *nameref)
{
- int i;
+ struct stringhead *head;
+ string_t *entry;
+ uint32_t hashval;
+ uint32_t hash_index;
+ uint32_t lock_index;
+ int retval = ENOENT;
- name_cache_lock();
- i = remove_name_locked(nameref);
- name_cache_unlock();
+ hashval = hash_string(nameref, 0);
- return(i);
-
-}
+ /*
+ * take this lock 'shared' to keep the hash stable
+ * if someone else decides to grow the pool they
+ * will take this lock exclusively
+ */
+ lck_rw_lock_shared(strtable_rw_lock);
+ /*
+ * must compute the head behind the table lock
+ * since the size and location of the table
+ * can change on the fly
+ */
+ hash_index = hashval & string_table_mask;
+ lock_index = hash_index % NUM_STRCACHE_LOCKS;
+ head = &string_ref_table[hash_index];
-static int
-remove_name_locked(const char *nameref)
-{
- struct stringhead *head;
- string_t *entry;
- uint32_t hashval;
- char * ptr;
-
- hashval = hash_string(nameref, 0);
- head = &string_ref_table[hashval & string_table_mask];
- for (entry=head->lh_first; entry != NULL; entry=entry->hash_chain.le_next) {
- if (entry->str == (unsigned char *)nameref) {
- entry->refcount--;
- if (entry->refcount == 0) {
- LIST_REMOVE(entry, hash_chain);
- if (head->lh_first == NULL) {
- filled_buckets--;
- }
- ptr = entry->str;
- entry->str = NULL;
- nstrings--;
+ lck_mtx_lock_spin(&strcache_mtx_locks[lock_index]);
- FREE(entry, M_TEMP);
- } else {
- num_dups--;
- }
+ for (entry = head->lh_first; entry != NULL; entry = entry->hash_chain.le_next) {
+ if (entry->str == nameref) {
+ entry->refcount--;
+
+ if (entry->refcount == 0) {
+ LIST_REMOVE(entry, hash_chain);
- return 0;
+ if (head->lh_first == NULL) {
+ OSAddAtomic(-1, &filled_buckets);
+ }
+ } else {
+ entry = NULL;
+ }
+ retval = 0;
+ break;
+ }
}
- }
+ lck_mtx_unlock(&strcache_mtx_locks[lock_index]);
+ lck_rw_done(strtable_rw_lock);
- return ENOENT;
+ if (entry != NULL)
+ FREE(entry, M_TEMP);
+
+ return retval;
}
+#ifdef DUMP_STRING_TABLE
void
dump_string_table(void)
{
string_t *entry;
u_long i;
- name_cache_lock();
+ lck_rw_lock_shared(strtable_rw_lock);
+
for (i = 0; i <= string_table_mask; i++) {
head = &string_ref_table[i];
for (entry=head->lh_first; entry != NULL; entry=entry->hash_chain.le_next) {
printf("%6d - %s\n", entry->refcount, entry->str);
}
}
- name_cache_unlock();
+ lck_rw_done(strtable_rw_lock);
}
+#endif /* DUMP_STRING_TABLE */
projects / apple / xnu.git / blobdiff