Unified getcwd() implementation
Marc Olzheim
marcolz at stack.nl
Fri May 7 02:22:40 PDT 2004
Hi,
(Re: http://lists.freebsd.org/pipermail/freebsd-arch/2003-August/001152.html)
> Yes, it's quite an old patch, and much has happened since it was written.
Mostly some fine-grained locking was introduced.
I hope I got everything covered. Here Bruce's patch reworked, that works
for me. (even over NFS ;-))
Anyone care to share their view on it ?
Marc
-------------- next part --------------
--- /usr/src/sys/kern/vfs_cache.c Mon Apr 5 23:03:36 2004
+++ /usr/src/sys/kern/vfs_cache.c Fri May 7 10:39:48 2004
@@ -35,6 +35,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/vfs_cache.c,v 1.87 2004/04/05 21:03:36 imp Exp $");
+#include "opt_mac.h"
+
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
@@ -51,8 +53,11 @@
#include <sys/filedesc.h>
#include <sys/fnv_hash.h>
-#include <vm/uma.h>
-
+#include <sys/file.h>
+#include <sys/uio.h>
+#include <sys/mac.h>
+#include <sys/dirent.h>
+#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
/*
* This structure describes the elements in the cache of recent
* names looked up by namei.
@@ -69,6 +74,8 @@
char nc_name[0]; /* segment name */
};
+#include <vm/uma.h>
+
/*
* Name caching works as follows:
*
@@ -778,6 +785,13 @@
};
#endif
+static int getcwd_impl(struct vnode *lvp, struct vnode *rvp, char **bpp,
+ char *bufp, struct thread *td);
+static int getcwd_scandir(struct vnode **, struct vnode **, char **, char *,
+ struct thread *);
+
+#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
+
/*
* XXX All of these sysctls would probably be more productive dead.
*/
@@ -791,6 +805,7 @@
static u_long numcwdfail2; STATNODE(CTLFLAG_RD, numcwdfail2, &numcwdfail2);
static u_long numcwdfail3; STATNODE(CTLFLAG_RD, numcwdfail3, &numcwdfail3);
static u_long numcwdfail4; STATNODE(CTLFLAG_RD, numcwdfail4, &numcwdfail4);
+static u_long numcwdfail5; STATNODE(CTLFLAG_RD, numcwdfail5, &numcwdfail5);
static u_long numcwdfound; STATNODE(CTLFLAG_RD, numcwdfound, &numcwdfound);
/* Implementation of the getcwd syscall */
@@ -803,14 +818,20 @@
return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen));
}
+/*
+ * Find pathname of process's current directory.
+ *
+ * Use vfs vnode-to-name reverse cache; if that fails, fall back
+ * to reading directory contents.
+ */
int
kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
{
- char *bp, *tmpbuf;
- int error, i, slash_prefixed;
+ char *bp, *bufp;
+ int error;
struct filedesc *fdp;
- struct namecache *ncp;
- struct vnode *vp;
+ struct vnode *rvp;
+ struct vnode *lvp;
numcwdcalls++;
if (disablecwd)
@@ -819,82 +840,422 @@
return (EINVAL);
if (buflen > MAXPATHLEN)
buflen = MAXPATHLEN;
+
+ buflen *= 4; /* XXX */
+
error = 0;
- tmpbuf = bp = malloc(buflen, M_TEMP, M_WAITOK);
+ bufp = bp = malloc(buflen, M_TEMP, M_WAITOK);
bp += buflen - 1;
*bp = '\0';
+
fdp = td->td_proc->p_fd;
- slash_prefixed = 0;
+
FILEDESC_LOCK(fdp);
- for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) {
- if (vp->v_vflag & VV_ROOT) {
- if (vp->v_mount == NULL) { /* forced unmount */
- FILEDESC_UNLOCK(fdp);
- free(tmpbuf, M_TEMP);
- return (EBADF);
- }
- vp = vp->v_mount->mnt_vnodecovered;
- continue;
+
+ rvp = fdp->fd_rdir;
+ if (rvp == NULL)
+ rvp = rootvnode;
+ VREF(rvp);
+
+ lvp = fdp->fd_cdir;
+
+ /* We have all the info we need from fdp. */
+ FILEDESC_UNLOCK(fdp);
+
+ error = getcwd_impl(lvp, rvp, &bp, bufp, td);
+ if (!error) {
+ numcwdfound++;
+ if (bufseg == UIO_SYSSPACE)
+ bcopy(bp, buf, strlen(bp) + 1);
+ else
+ error = copyout(bp, buf, strlen(bp) + 1);
+ } else {
+#if DIAGNOSTIC
+ printf("getcwd: error %d\n", error);
+#endif
+ }
+
+ vrele(rvp);
+ free(bufp, M_TEMP);
+ return (error);
+}
+
+/*
+ * Recursively advance up the directory hierarchy from lvp to rvp.
+ * Look in the namecache first for each path component; if it cannot
+ * be found, use scandir to find it. Copy the result into the buffer
+ * pointed to by bufp from *bpp onwards.
+ */
+
+static int
+getcwd_impl(lvp, rvp, bpp, bufp, td)
+ struct vnode *lvp;
+ struct vnode *rvp;
+ char **bpp;
+ char *bufp;
+ struct thread *td;
+{
+ int i, error, slash_prefixed;
+ struct namecache *ncp;
+ struct vnode *uvp;
+ struct vnode *tvp;
+ char *bp;
+
+ error = slash_prefixed = 0;
+ uvp = NULL;
+
+ VREF(lvp);
+ error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
+ if (error) {
+ numcwdfail5++;
+ vrele(lvp);
+ lvp = NULL;
+ goto out;
+ }
+ if (bufp)
+ bp = *bpp;
+
+ while (lvp != rvp) {
+#if 1
+ if (lvp->v_type != VDIR) {
+ numcwdfail1++;
+ error = ENOTDIR;
+ goto out;
}
- if (vp->v_dd->v_id != vp->v_ddid) {
- FILEDESC_UNLOCK(fdp);
+#else
+ if (lvp->v_dd->v_id != lvp->v_ddid) {
numcwdfail1++;
- free(tmpbuf, M_TEMP);
- return (ENOTDIR);
+ error = ENOTDIR;
+ goto out;
}
- CACHE_LOCK();
- ncp = TAILQ_FIRST(&vp->v_cache_dst);
- if (!ncp) {
- numcwdfail2++;
- CACHE_UNLOCK();
- FILEDESC_UNLOCK(fdp);
- free(tmpbuf, M_TEMP);
- return (ENOENT);
+#endif
+ /*
+ * step up if we're a covered vnode.
+ */
+ while (lvp->v_vflag & VV_ROOT) {
+ if (lvp == rvp)
+ goto out;
+ tvp = lvp;
+ lvp = lvp->v_mount->mnt_vnodecovered;
+ vput(tvp);
+ if (lvp == NULL) {
+ numcwdfail3++;
+ error = ENOENT;
+ goto out;
+ }
+ VREF(lvp);
+ error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
+ if (error != 0) {
+ numcwdfail5++;
+ vrele(lvp);
+ lvp = NULL;
+ goto out;
+ }
}
- if (ncp->nc_dvp != vp->v_dd) {
- numcwdfail3++;
- CACHE_UNLOCK();
- FILEDESC_UNLOCK(fdp);
- free(tmpbuf, M_TEMP);
- return (EBADF);
- }
- for (i = ncp->nc_nlen - 1; i >= 0; i--) {
- if (bp == tmpbuf) {
- numcwdfail4++;
+ /*
+ * look in the cache first
+ */
+ CACHE_LOCK();
+ ncp = TAILQ_FIRST(&lvp->v_cache_dst);
+#if DIAGNOSTIC
+ /* XXX simulate cache failure every 10 lookups */
+ if ((numcwdcalls % 10) == 0)
+ ncp = NULL;
+#endif
+ if (ncp) {
+ if (ncp->nc_dvp != lvp->v_dd) {
CACHE_UNLOCK();
- FILEDESC_UNLOCK(fdp);
- free(tmpbuf, M_TEMP);
- return (ENOMEM);
+ numcwdfail3++;
+ error = EBADF;
+ goto out;
+ }
+ for (i = ncp->nc_nlen - 1; i >= 0; i--) {
+ if (bp == bufp) {
+ CACHE_UNLOCK();
+ numcwdfail4++;
+ error = ENOMEM;
+ goto out;
+ }
+ *--bp = ncp->nc_name[i];
}
- *--bp = ncp->nc_name[i];
- }
- if (bp == tmpbuf) {
- numcwdfail4++;
CACHE_UNLOCK();
- FILEDESC_UNLOCK(fdp);
- free(tmpbuf, M_TEMP);
- return (ENOMEM);
+ /*
+ * must ensure lvp is always locked and ref'd
+ */
+ tvp = lvp;
+ lvp = lvp->v_dd;
+ vput(tvp);
+ if (lvp == NULL) {
+ numcwdfail3++;
+ error = ENOENT;
+ goto out;
+ }
+ VREF(lvp);
+ error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
+ if (error != 0) {
+ numcwdfail5++;
+ vrele(lvp);
+ lvp = NULL;
+ goto out;
+ }
+ } else {
+ CACHE_UNLOCK();
+ numcwdfail2++;
+#if DIAGNOSTIC
+ printf("getcwd: using scandir\n");
+#endif
+ error = getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
+ if (error) {
+#if DIAGNOSTIC
+ printf("getcwd_scandir returned %d\n", error);
+#endif
+ goto out;
+ }
+#if DIAGNOSTIC
+ if (lvp != NULL)
+ panic("getcwd: oops, forgot to null lvp");
+#endif
+ lvp = uvp;
+ uvp = NULL;
}
+#if DIAGNOSTIC
+ if (bufp && (bp <= bufp))
+ panic("getcwd: oops, went back too far");
+#endif
*--bp = '/';
slash_prefixed = 1;
- vp = vp->v_dd;
- CACHE_UNLOCK();
}
- FILEDESC_UNLOCK(fdp);
+
if (!slash_prefixed) {
- if (bp == tmpbuf) {
+ if (bp == bufp) {
numcwdfail4++;
- free(tmpbuf, M_TEMP);
- return (ENOMEM);
+ error = ENOMEM;
+ goto out;
}
*--bp = '/';
}
- numcwdfound++;
- if (bufseg == UIO_SYSSPACE)
- bcopy(bp, buf, strlen(bp) + 1);
- else
- error = copyout(bp, buf, strlen(bp) + 1);
- free(tmpbuf, M_TEMP);
+out:
+ if (bpp)
+ *bpp = bp;
+ if (uvp)
+ vput(uvp);
+ if (lvp)
+ vput(lvp);
+ return (error);
+}
+
+/*
+ * Vnode variable naming conventions in this file:
+ *
+ * rvp: the current root we're aiming towards.
+ * lvp, *lvpp: the "lower" vnode
+ * uvp, *uvpp: the "upper" vnode.
+ *
+ * Since all the vnodes we're dealing with are directories, and the
+ * lookups are going *up* in the filesystem rather than *down*, the
+ * usual "pvp" (parent) or "dvp" (directory) naming conventions are
+ * too confusing.
+ */
+
+/*
+ * XXX Will infinite loop in certain cases if a directory read reliably
+ * returns EINVAL on last block.
+ * XXX is EINVAL the right thing to return if a directory is malformed?
+ */
+
+/*
+ * XXX Untested vs. mount -o union; probably does the wrong thing.
+ */
+
+/*
+ * Find parent vnode of *lvpp, return in *uvpp
+ *
+ * If we care about the name, scan it looking for name of directory
+ * entry pointing at lvp.
+ *
+ * Place the name in the buffer which starts at bufp, immediately
+ * before *bpp, and move bpp backwards to point at the start of it.
+ *
+ * On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
+ * On exit, *uvpp is either NULL or is a locked vnode reference.
+ */
+
+static int
+getcwd_scandir(lvpp, uvpp, bpp, bufp, td)
+ struct vnode **lvpp;
+ struct vnode **uvpp;
+ char **bpp;
+ char *bufp;
+ struct thread *td;
+{
+ int error = 0;
+ int eofflag;
+ off_t off;
+ int tries;
+ struct uio uio;
+ struct iovec iov;
+ char *dirbuf = NULL;
+ int dirbuflen;
+ ino_t fileno;
+ struct vattr va;
+ struct vnode *uvp = NULL;
+ struct vnode *lvp = *lvpp;
+ struct componentname cn;
+ int len, reclen;
+ tries = 0;
+
+ /*
+ * If we want the filename, get some info we need while the
+ * current directory is still locked.
+ */
+ if (bufp != NULL) {
+ error = VOP_GETATTR(lvp, &va, td->td_ucred, td);
+ if (error) {
+ vput(lvp);
+ *lvpp = NULL;
+ *uvpp = NULL;
+#if DIAGNOSTICS
+ printf("VOP_GETATTR returned %d", error);
+#endif
+ return error;
+ }
+ }
+
+ /*
+ * Ok, we have to do it the hard way..
+ * Next, get parent vnode using lookup of ..
+ */
+ cn.cn_nameiop = LOOKUP;
+ cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY;
+ cn.cn_thread = td;
+ cn.cn_cred = td->td_ucred;
+ cn.cn_pnbuf = NULL;
+ cn.cn_nameptr = "..";
+ cn.cn_namelen = 2;
+ cn.cn_consume = 0;
+
+ /*
+ * At this point, lvp is locked and will be unlocked by the lookup.
+ * On successful return, *uvpp will be locked
+ */
+ error = VOP_LOOKUP(lvp, uvpp, &cn);
+ if (error) {
+ vput(lvp);
+ *lvpp = NULL;
+ *uvpp = NULL;
+ return error;
+ }
+ uvp = *uvpp;
+
+ /* If we don't care about the pathname, we're done */
+ if (bufp == NULL) {
+ vrele(lvp);
+ *lvpp = NULL;
+ return 0;
+ }
+
+ fileno = va.va_fileid;
+
+ dirbuflen = DIRBLKSIZ;
+ if (dirbuflen < va.va_blocksize)
+ dirbuflen = va.va_blocksize;
+ dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
+
+#if 0
+unionread:
+#endif
+ off = 0;
+ do {
+ /* call VOP_READDIR of parent */
+ iov.iov_base = dirbuf;
+ iov.iov_len = dirbuflen;
+
+ uio.uio_iov = &iov;
+ uio.uio_iovcnt = 1;
+ uio.uio_offset = off;
+ uio.uio_resid = dirbuflen;
+ uio.uio_segflg = UIO_SYSSPACE;
+ uio.uio_rw = UIO_READ;
+ uio.uio_td = td;
+
+ eofflag = 0;
+
+#ifdef MAC
+ error = mac_check_vnode_readdir(td->td_ucred, uvp);
+ if (error == 0)
+#endif /* MAC */
+ error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag,
+ 0, 0);
+
+ off = uio.uio_offset;
+
+ /*
+ * Try again if NFS tosses its cookies.
+ * XXX this can still loop forever if the directory is busted
+ * such that the second or subsequent page of it always
+ * returns EINVAL
+ */
+ if ((error == EINVAL) && (tries < 3)) {
+ off = 0;
+ tries++;
+ continue; /* once more, with feeling */
+ }
+
+ if (!error) {
+ char *cpos;
+ struct dirent *dp;
+
+ cpos = dirbuf;
+ tries = 0;
+
+ /* scan directory page looking for matching vnode */
+ for (len = (dirbuflen - uio.uio_resid);
+ len > 0;
+ len -= reclen)
+ {
+ dp = (struct dirent *) cpos;
+ reclen = dp->d_reclen;
+
+ /* check for malformed directory.. */
+ if (reclen < DIRENT_MINSIZE) {
+ error = EINVAL;
+ goto out;
+ }
+ /*
+ * XXX should perhaps do VOP_LOOKUP to
+ * check that we got back to the right place,
+ * but getting the locking games for that
+ * right would be heinous.
+ */
+ if ((dp->d_type != DT_WHT) &&
+ (dp->d_fileno == fileno)) {
+ char *bp = *bpp;
+ bp -= dp->d_namlen;
+#if DIAGNOSTIC
+ printf("bp: %p bufp: %p dp->d_name: %s"
+ " (%d)\n",
+ bp, bufp,
+ dp->d_name, dp->d_namlen);
+#endif
+ if (bp <= bufp) {
+ error = ERANGE;
+ goto out;
+ }
+ bcopy(dp->d_name, bp, dp->d_namlen);
+ error = 0;
+ *bpp = bp;
+ goto out;
+ }
+ cpos += reclen;
+ }
+ }
+ } while (!eofflag);
+ error = ENOENT;
+
+out:
+ vrele(lvp);
+ *lvpp = NULL;
+ free(dirbuf, M_TEMP);
return (error);
}
--- /usr/src/sys/compat/linux/linux_getcwd.c Mon Nov 17 19:57:20 2003
+++ /usr/src/sys/compat/linux/linux_getcwd.c Fri May 7 11:12:28 2004
@@ -40,435 +40,27 @@
__FBSDID("$FreeBSD: src/sys/compat/linux/linux_getcwd.c,v 1.14 2003/11/17 18:57:20 rwatson Exp $");
#include "opt_compat.h"
-#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
-#include <sys/namei.h>
-#include <sys/filedesc.h>
-#include <sys/kernel.h>
-#include <sys/file.h>
-#include <sys/stat.h>
-#include <sys/syscallsubr.h>
-#include <sys/vnode.h>
-#include <sys/mount.h>
#include <sys/proc.h>
-#include <sys/uio.h>
-#include <sys/mac.h>
-#include <sys/malloc.h>
-#include <sys/dirent.h>
-#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
+#include <sys/syscallsubr.h>
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#include <compat/linux/linux_util.h>
-static int
-linux_getcwd_scandir(struct vnode **, struct vnode **,
- char **, char *, struct thread *);
-static int
-linux_getcwd_common(struct vnode *, struct vnode *,
- char **, char *, int, int, struct thread *);
-
-#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
-
-/*
- * Vnode variable naming conventions in this file:
- *
- * rvp: the current root we're aiming towards.
- * lvp, *lvpp: the "lower" vnode
- * uvp, *uvpp: the "upper" vnode.
- *
- * Since all the vnodes we're dealing with are directories, and the
- * lookups are going *up* in the filesystem rather than *down*, the
- * usual "pvp" (parent) or "dvp" (directory) naming conventions are
- * too confusing.
- */
-
-/*
- * XXX Will infinite loop in certain cases if a directory read reliably
- * returns EINVAL on last block.
- * XXX is EINVAL the right thing to return if a directory is malformed?
- */
-
-/*
- * XXX Untested vs. mount -o union; probably does the wrong thing.
- */
-
-/*
- * Find parent vnode of *lvpp, return in *uvpp
- *
- * If we care about the name, scan it looking for name of directory
- * entry pointing at lvp.
- *
- * Place the name in the buffer which starts at bufp, immediately
- * before *bpp, and move bpp backwards to point at the start of it.
- *
- * On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
- * On exit, *uvpp is either NULL or is a locked vnode reference.
- */
-static int
-linux_getcwd_scandir(lvpp, uvpp, bpp, bufp, td)
- struct vnode **lvpp;
- struct vnode **uvpp;
- char **bpp;
- char *bufp;
- struct thread *td;
-{
- int error = 0;
- int eofflag;
- off_t off;
- int tries;
- struct uio uio;
- struct iovec iov;
- char *dirbuf = NULL;
- int dirbuflen;
- ino_t fileno;
- struct vattr va;
- struct vnode *uvp = NULL;
- struct vnode *lvp = *lvpp;
- struct componentname cn;
- int len, reclen;
- tries = 0;
-
- /*
- * If we want the filename, get some info we need while the
- * current directory is still locked.
- */
- if (bufp != NULL) {
- error = VOP_GETATTR(lvp, &va, td->td_ucred, td);
- if (error) {
- vput(lvp);
- *lvpp = NULL;
- *uvpp = NULL;
- return error;
- }
- }
-
- /*
- * Ok, we have to do it the hard way..
- * Next, get parent vnode using lookup of ..
- */
- cn.cn_nameiop = LOOKUP;
- cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY;
- cn.cn_thread = td;
- cn.cn_cred = td->td_ucred;
- cn.cn_pnbuf = NULL;
- cn.cn_nameptr = "..";
- cn.cn_namelen = 2;
- cn.cn_consume = 0;
-
- /*
- * At this point, lvp is locked and will be unlocked by the lookup.
- * On successful return, *uvpp will be locked
- */
-#ifdef MAC
- error = mac_check_vnode_lookup(td->td_ucred, lvp, &cn);
- if (error == 0)
-#endif
- error = VOP_LOOKUP(lvp, uvpp, &cn);
- if (error) {
- vput(lvp);
- *lvpp = NULL;
- *uvpp = NULL;
- return error;
- }
- uvp = *uvpp;
-
- /* If we don't care about the pathname, we're done */
- if (bufp == NULL) {
- vrele(lvp);
- *lvpp = NULL;
- return 0;
- }
-
- fileno = va.va_fileid;
-
- dirbuflen = DIRBLKSIZ;
- if (dirbuflen < va.va_blocksize)
- dirbuflen = va.va_blocksize;
- dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
-
-#if 0
-unionread:
-#endif
- off = 0;
- do {
- /* call VOP_READDIR of parent */
- iov.iov_base = dirbuf;
- iov.iov_len = dirbuflen;
-
- uio.uio_iov = &iov;
- uio.uio_iovcnt = 1;
- uio.uio_offset = off;
- uio.uio_resid = dirbuflen;
- uio.uio_segflg = UIO_SYSSPACE;
- uio.uio_rw = UIO_READ;
- uio.uio_td = td;
-
- eofflag = 0;
-
-#ifdef MAC
- error = mac_check_vnode_readdir(td->td_ucred, uvp);
- if (error == 0)
-#endif /* MAC */
- error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag,
- 0, 0);
-
- off = uio.uio_offset;
-
- /*
- * Try again if NFS tosses its cookies.
- * XXX this can still loop forever if the directory is busted
- * such that the second or subsequent page of it always
- * returns EINVAL
- */
- if ((error == EINVAL) && (tries < 3)) {
- off = 0;
- tries++;
- continue; /* once more, with feeling */
- }
-
- if (!error) {
- char *cpos;
- struct dirent *dp;
-
- cpos = dirbuf;
- tries = 0;
-
- /* scan directory page looking for matching vnode */
- for (len = (dirbuflen - uio.uio_resid); len > 0; len -= reclen) {
- dp = (struct dirent *) cpos;
- reclen = dp->d_reclen;
-
- /* check for malformed directory.. */
- if (reclen < DIRENT_MINSIZE) {
- error = EINVAL;
- goto out;
- }
- /*
- * XXX should perhaps do VOP_LOOKUP to
- * check that we got back to the right place,
- * but getting the locking games for that
- * right would be heinous.
- */
- if ((dp->d_type != DT_WHT) &&
- (dp->d_fileno == fileno)) {
- char *bp = *bpp;
- bp -= dp->d_namlen;
-
- if (bp <= bufp) {
- error = ERANGE;
- goto out;
- }
- bcopy(dp->d_name, bp, dp->d_namlen);
- error = 0;
- *bpp = bp;
- goto out;
- }
- cpos += reclen;
- }
- }
- } while (!eofflag);
- error = ENOENT;
-
-out:
- vrele(lvp);
- *lvpp = NULL;
- free(dirbuf, M_TEMP);
- return error;
-}
-
-
-/*
- * common routine shared by sys___getcwd() and linux_vn_isunder()
- */
-
-#define GETCWD_CHECK_ACCESS 0x0001
-
-static int
-linux_getcwd_common (lvp, rvp, bpp, bufp, limit, flags, td)
- struct vnode *lvp;
- struct vnode *rvp;
- char **bpp;
- char *bufp;
- int limit;
- int flags;
- struct thread *td;
-{
- struct filedesc *fdp = td->td_proc->p_fd;
- struct vnode *uvp = NULL;
- char *bp = NULL;
- int error;
- int perms = VEXEC;
-
- if (rvp == NULL) {
- rvp = fdp->fd_rdir;
- if (rvp == NULL)
- rvp = rootvnode;
- }
-
- VREF(rvp);
- VREF(lvp);
-
- /*
- * Error handling invariant:
- * Before a `goto out':
- * lvp is either NULL, or locked and held.
- * uvp is either NULL, or locked and held.
- */
-
- error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
- if (error) {
- vrele(lvp);
- lvp = NULL;
- goto out;
- }
- if (bufp)
- bp = *bpp;
- /*
- * this loop will terminate when one of the following happens:
- * - we hit the root
- * - getdirentries or lookup fails
- * - we run out of space in the buffer.
- */
- if (lvp == rvp) {
- if (bp)
- *(--bp) = '/';
- goto out;
- }
- do {
- if (lvp->v_type != VDIR) {
- error = ENOTDIR;
- goto out;
- }
-
- /*
- * access check here is optional, depending on
- * whether or not caller cares.
- */
- if (flags & GETCWD_CHECK_ACCESS) {
- error = VOP_ACCESS(lvp, perms, td->td_ucred, td);
- if (error)
- goto out;
- perms = VEXEC|VREAD;
- }
-
- /*
- * step up if we're a covered vnode..
- */
- while (lvp->v_vflag & VV_ROOT) {
- struct vnode *tvp;
-
- if (lvp == rvp)
- goto out;
-
- tvp = lvp;
- lvp = lvp->v_mount->mnt_vnodecovered;
- vput(tvp);
- /*
- * hodie natus est radici frater
- */
- if (lvp == NULL) {
- error = ENOENT;
- goto out;
- }
- VREF(lvp);
- error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
- if (error != 0) {
- vrele(lvp);
- lvp = NULL;
- goto out;
- }
- }
- error = linux_getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
- if (error)
- goto out;
-#if DIAGNOSTIC
- if (lvp != NULL)
- panic("getcwd: oops, forgot to null lvp");
- if (bufp && (bp <= bufp)) {
- panic("getcwd: oops, went back too far");
- }
-#endif
- if (bp)
- *(--bp) = '/';
- lvp = uvp;
- uvp = NULL;
- limit--;
- } while ((lvp != rvp) && (limit > 0));
-
-out:
- if (bpp)
- *bpp = bp;
- if (uvp)
- vput(uvp);
- if (lvp)
- vput(lvp);
- vrele(rvp);
- return error;
-}
-
-
/*
* Find pathname of process's current directory.
- *
- * Use vfs vnode-to-name reverse cache; if that fails, fall back
- * to reading directory contents.
+ * Simply use the new, complete getcwd() implementation.
*/
int
linux_getcwd(struct thread *td, struct linux_getcwd_args *args)
{
- caddr_t bp, bend, path;
- int error, len, lenused;
-
#ifdef DEBUG
printf("Linux-emul(%ld): getcwd(%p, %ld)\n", (long)td->td_proc->p_pid,
args->buf, (long)args->bufsize);
#endif
-
- len = args->bufsize;
-
- if (len > MAXPATHLEN*4)
- len = MAXPATHLEN*4;
- else if (len < 2)
- return ERANGE;
-
- path = (char *)malloc(len, M_TEMP, M_WAITOK);
-
- error = kern___getcwd(td, path, UIO_SYSSPACE, len);
- if (!error) {
- lenused = strlen(path) + 1;
- if (lenused <= args->bufsize) {
- td->td_retval[0] = lenused;
- error = copyout(path, args->buf, lenused);
- }
- else
- error = ERANGE;
- } else {
- bp = &path[len];
- bend = bp;
- *(--bp) = '\0';
-
- /*
- * 5th argument here is "max number of vnodes to traverse".
- * Since each entry takes up at least 2 bytes in the output buffer,
- * limit it to N/2 vnodes for an N byte buffer.
- */
-
- error = linux_getcwd_common (td->td_proc->p_fd->fd_cdir, NULL,
- &bp, path, len/2, GETCWD_CHECK_ACCESS, td);
-
- if (error)
- goto out;
- lenused = bend - bp;
- td->td_retval[0] = lenused;
- /* put the result into user buffer */
- error = copyout(bp, args->buf, lenused);
- }
-out:
- free(path, M_TEMP);
- return (error);
+ return (kern___getcwd(td, args->buf, UIO_USERSPACE, args->bufsize));
}
-
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