svn commit: r321010 - stable/10/sys/compat/linux
Dmitry Chagin
dchagin at FreeBSD.org
Sat Jul 15 14:57:26 UTC 2017
Author: dchagin
Date: Sat Jul 15 14:57:24 2017
New Revision: 321010
URL: https://svnweb.freebsd.org/changeset/base/321010
Log:
MFC r281882(by trasz@):
Simplify linux_getcwd(), removing code that was longer used.
Modified:
stable/10/sys/compat/linux/linux_getcwd.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/compat/linux/linux_getcwd.c
==============================================================================
--- stable/10/sys/compat/linux/linux_getcwd.c Sat Jul 15 14:48:31 2017 (r321009)
+++ stable/10/sys/compat/linux/linux_getcwd.c Sat Jul 15 14:57:24 2017 (r321010)
@@ -2,11 +2,15 @@
/* $NetBSD: vfs_getcwd.c,v 1.3.2.3 1999/07/11 10:24:09 sommerfeld Exp $ */
/*-
* Copyright (c) 1999 The NetBSD Foundation, Inc.
+ * Copyright (c) 2015 The FreeBSD Foundation
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Bill Sommerfeld.
*
+ * Portions of this software were developed by Edward Tomasz Napierala
+ * under sponsorship from the FreeBSD Foundation.
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -36,19 +40,9 @@ __FBSDID("$FreeBSD$");
#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/malloc.h>
-#include <sys/dirent.h>
-#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
@@ -60,408 +54,37 @@ __FBSDID("$FreeBSD$");
#include <compat/linux/linux_misc.h>
#include <compat/linux/linux_util.h>
-#include <security/mac/mac_framework.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);
- 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;
- cn.cn_lkflags = LK_SHARED;
-
- /*
- * At this point, lvp is locked and will be unlocked by the lookup.
- * On successful return, *uvpp will be locked
- */
-#ifdef MAC
- error = mac_vnode_check_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) {
- vput(lvp);
- *lvpp = NULL;
- return 0;
- }
-
- fileno = va.va_fileid;
-
- dirbuflen = DIRBLKSIZ;
- if (dirbuflen < va.va_blocksize)
- dirbuflen = va.va_blocksize;
- dirbuf = malloc(dirbuflen, M_LINUX, 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_vnode_check_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:
- vput(lvp);
- *lvpp = NULL;
- free(dirbuf, M_LINUX);
- 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;
- accmode_t accmode = 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);
- if (error != 0)
- panic("vn_lock LK_RETRY returned error %d", error);
- 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, accmode, td->td_ucred, td);
- if (error)
- goto out;
- accmode = 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);
- if (error != 0)
- panic("vn_lock LK_RETRY returned %d", error);
- }
- error = linux_getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
- if (error)
- goto out;
-#ifdef 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.
*/
-
int
linux_getcwd(struct thread *td, struct linux_getcwd_args *args)
{
- char *bp, *bend, *path;
- int error, len, lenused;
+ char *path;
+ int error, lenused;
#ifdef DEBUG
if (ldebug(getcwd))
printf(ARGS(getcwd, "%p, %ld"), args->buf, (long)args->bufsize);
#endif
- len = args->bufsize;
+ /*
+ * Linux returns ERANGE instead of EINVAL.
+ */
+ if (args->bufsize < 2)
+ return (ERANGE);
- if (len > LINUX_PATH_MAX)
- len = LINUX_PATH_MAX;
- else if (len < 2)
- return ERANGE;
+ path = malloc(LINUX_PATH_MAX, M_TEMP, M_WAITOK);
- path = malloc(len, M_TEMP, M_WAITOK);
-
- error = kern___getcwd(td, path, UIO_SYSSPACE, len, LINUX_PATH_MAX);
- if (!error) {
+ error = kern___getcwd(td, path, UIO_SYSSPACE, args->bufsize,
+ LINUX_PATH_MAX);
+ if (error == 0) {
lenused = strlen(path) + 1;
- if (lenused <= args->bufsize) {
+ error = copyout(path, args->buf, lenused);
+ if (error == 0)
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);
}
-
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