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9p: remove support for the "handle" backend

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The "handle" fsdev backend was deprecated in QEMU 2.12.0 with:

commit db3b3c7281
Author: Greg Kurz <groug@kaod.org>
Date:   Mon Jan 8 11:18:23 2018 +0100

    9pfs: deprecate handle backend

    This backend raise some concerns:

    - doesn't support symlinks
    - fails +100 tests in the PJD POSIX file system test suite [1]
    - requires the QEMU process to run with the CAP_DAC_READ_SEARCH
      capability, which isn't recommended for security reasons

    This backend should not be used and wil be removed. The 'local'
    backend is the recommended alternative.

    [1] https://www.tuxera.com/community/posix-test-suite/

    Signed-off-by: Greg Kurz <groug@kaod.org>
    Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
    Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

It has passed the two release cooling period without any complaint.

Remove it now.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Greg Kurz 2018-12-12 14:18:10 +01:00
parent 75607e0dcc
commit 93aee84f57
5 changed files with 4 additions and 726 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fsdev/qemu-fsdev.c
View File

@ -23,9 +23,6 @@ static QTAILQ_HEAD(FsDriverEntry_head, FsDriverListEntry) fsdriver_entries =
static FsDriverTable FsDrivers[] = {
{ .name = "local", .ops = &local_ops},
#ifdef CONFIG_OPEN_BY_HANDLE
{ .name = "handle", .ops = &handle_ops},
#endif
{ .name = "synth", .ops = &synth_ops},
{ .name = "proxy", .ops = &proxy_ops},
};

710
hw/9pfs/9p-handle.c
View File

@ -1,710 +0,0 @@
/*
* 9p handle callback
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "9p.h"
#include "9p-xattr.h"
#include <arpa/inet.h>
#include <pwd.h>
#include <grp.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "qapi/error.h"
#include "qemu/xattr.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include <linux/fs.h>
#ifdef CONFIG_LINUX_MAGIC_H
#include <linux/magic.h>
#endif
#include <sys/ioctl.h>
#ifndef XFS_SUPER_MAGIC
#define XFS_SUPER_MAGIC 0x58465342
#endif
#ifndef EXT2_SUPER_MAGIC
#define EXT2_SUPER_MAGIC 0xEF53
#endif
#ifndef REISERFS_SUPER_MAGIC
#define REISERFS_SUPER_MAGIC 0x52654973
#endif
#ifndef BTRFS_SUPER_MAGIC
#define BTRFS_SUPER_MAGIC 0x9123683E
#endif
typedef struct HandleData {
int mountfd;
int handle_bytes;
} HandleData;
static inline int name_to_handle(int dirfd, const char *name,
struct file_handle *fh, int *mnt_id, int flags)
{
return name_to_handle_at(dirfd, name, fh, mnt_id, flags);
}
static inline int open_by_handle(int mountfd, const char *fh, int flags)
{
return open_by_handle_at(mountfd, (struct file_handle *)fh, flags);
}
static int handle_update_file_cred(int dirfd, const char *name, FsCred *credp)
{
int fd, ret;
fd = openat(dirfd, name, O_NONBLOCK | O_NOFOLLOW);
if (fd < 0) {
return fd;
}
ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
if (ret < 0) {
goto err_out;
}
ret = fchmod(fd, credp->fc_mode & 07777);
err_out:
close(fd);
return ret;
}
static int handle_lstat(FsContext *fs_ctx, V9fsPath *fs_path,
struct stat *stbuf)
{
int fd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
if (fd < 0) {
return fd;
}
ret = fstatat(fd, "", stbuf, AT_EMPTY_PATH);
close(fd);
return ret;
}
static ssize_t handle_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
char *buf, size_t bufsz)
{
int fd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
if (fd < 0) {
return fd;
}
ret = readlinkat(fd, "", buf, bufsz);
close(fd);
return ret;
}
static int handle_close(FsContext *ctx, V9fsFidOpenState *fs)
{
return close(fs->fd);
}
static int handle_closedir(FsContext *ctx, V9fsFidOpenState *fs)
{
return closedir(fs->dir.stream);
}
static int handle_open(FsContext *ctx, V9fsPath *fs_path,
int flags, V9fsFidOpenState *fs)
{
HandleData *data = (HandleData *) ctx->private;
fs->fd = open_by_handle(data->mountfd, fs_path->data, flags);
return fs->fd;
}
static int handle_opendir(FsContext *ctx,
V9fsPath *fs_path, V9fsFidOpenState *fs)
{
int ret;
ret = handle_open(ctx, fs_path, O_DIRECTORY, fs);
if (ret < 0) {
return -1;
}
fs->dir.stream = fdopendir(ret);
if (!fs->dir.stream) {
return -1;
}
return 0;
}
static void handle_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
{
rewinddir(fs->dir.stream);
}
static off_t handle_telldir(FsContext *ctx, V9fsFidOpenState *fs)
{
return telldir(fs->dir.stream);
}
static struct dirent *handle_readdir(FsContext *ctx, V9fsFidOpenState *fs)
{
return readdir(fs->dir.stream);
}
static void handle_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
{
seekdir(fs->dir.stream, off);
}
static ssize_t handle_preadv(FsContext *ctx, V9fsFidOpenState *fs,
const struct iovec *iov,
int iovcnt, off_t offset)
{
#ifdef CONFIG_PREADV
return preadv(fs->fd, iov, iovcnt, offset);
#else
int err = lseek(fs->fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
return readv(fs->fd, iov, iovcnt);
}
#endif
}
static ssize_t handle_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
const struct iovec *iov,
int iovcnt, off_t offset)
{
ssize_t ret;
#ifdef CONFIG_PREADV
ret = pwritev(fs->fd, iov, iovcnt, offset);
#else
int err = lseek(fs->fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
ret = writev(fs->fd, iov, iovcnt);
}
#endif
#ifdef CONFIG_SYNC_FILE_RANGE
if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
/*
* Initiate a writeback. This is not a data integrity sync.
* We want to ensure that we don't leave dirty pages in the cache
* after write when writeout=immediate is sepcified.
*/
sync_file_range(fs->fd, offset, ret,
SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
}
#endif
return ret;
}
static int handle_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
{
int fd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = fchmod(fd, credp->fc_mode);
close(fd);
return ret;
}
static int handle_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
const char *name, FsCred *credp)
{
int dirfd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
if (dirfd < 0) {
return dirfd;
}
ret = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
if (!ret) {
ret = handle_update_file_cred(dirfd, name, credp);
}
close(dirfd);
return ret;
}
static int handle_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
const char *name, FsCred *credp)
{
int dirfd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
if (dirfd < 0) {
return dirfd;
}
ret = mkdirat(dirfd, name, credp->fc_mode);
if (!ret) {
ret = handle_update_file_cred(dirfd, name, credp);
}
close(dirfd);
return ret;
}
static int handle_fstat(FsContext *fs_ctx, int fid_type,
V9fsFidOpenState *fs, struct stat *stbuf)
{
int fd;
if (fid_type == P9_FID_DIR) {
fd = dirfd(fs->dir.stream);
} else {
fd = fs->fd;
}
return fstat(fd, stbuf);
}
static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
int flags, FsCred *credp, V9fsFidOpenState *fs)
{
int ret;
int dirfd, fd;
HandleData *data = (HandleData *) fs_ctx->private;
dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
if (dirfd < 0) {
return dirfd;
}
fd = openat(dirfd, name, flags | O_NOFOLLOW, credp->fc_mode);
if (fd >= 0) {
ret = handle_update_file_cred(dirfd, name, credp);
if (ret < 0) {
close(fd);
fd = ret;
} else {
fs->fd = fd;
}
}
close(dirfd);
return fd;
}
static int handle_symlink(FsContext *fs_ctx, const char *oldpath,
V9fsPath *dir_path, const char *name, FsCred *credp)
{
int fd, dirfd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
if (dirfd < 0) {
return dirfd;
}
ret = symlinkat(oldpath, dirfd, name);
if (!ret) {
fd = openat(dirfd, name, O_PATH | O_NOFOLLOW);
if (fd < 0) {
ret = fd;
goto err_out;
}
ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
close(fd);
}
err_out:
close(dirfd);
return ret;
}
static int handle_link(FsContext *ctx, V9fsPath *oldpath,
V9fsPath *dirpath, const char *name)
{
int oldfd, newdirfd, ret;
HandleData *data = (HandleData *) ctx->private;
oldfd = open_by_handle(data->mountfd, oldpath->data, O_PATH);
if (oldfd < 0) {
return oldfd;
}
newdirfd = open_by_handle(data->mountfd, dirpath->data, O_PATH);
if (newdirfd < 0) {
close(oldfd);
return newdirfd;
}
ret = linkat(oldfd, "", newdirfd, name, AT_EMPTY_PATH);
close(newdirfd);
close(oldfd);
return ret;
}
static int handle_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK | O_WRONLY);
if (fd < 0) {
return fd;
}
ret = ftruncate(fd, size);
close(fd);
return ret;
}
static int handle_rename(FsContext *ctx, const char *oldpath,
const char *newpath)
{
errno = EOPNOTSUPP;
return -1;
}
static int handle_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
{
int fd, ret;
HandleData *data = (HandleData *) fs_ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
if (fd < 0) {
return fd;
}
ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
close(fd);
return ret;
}
static int handle_utimensat(FsContext *ctx, V9fsPath *fs_path,
const struct timespec *buf)
{
int ret;
int fd;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = futimens(fd, buf);
close(fd);
return ret;
}
static int handle_remove(FsContext *ctx, const char *path)
{
errno = EOPNOTSUPP;
return -1;
}
static int handle_fsync(FsContext *ctx, int fid_type,
V9fsFidOpenState *fs, int datasync)
{
int fd;
if (fid_type == P9_FID_DIR) {
fd = dirfd(fs->dir.stream);
} else {
fd = fs->fd;
}
if (datasync) {
return qemu_fdatasync(fd);
} else {
return fsync(fd);
}
}
static int handle_statfs(FsContext *ctx, V9fsPath *fs_path,
struct statfs *stbuf)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = fstatfs(fd, stbuf);
close(fd);
return ret;
}
static ssize_t handle_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
const char *name, void *value, size_t size)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = fgetxattr(fd, name, value, size);
close(fd);
return ret;
}
static ssize_t handle_llistxattr(FsContext *ctx, V9fsPath *fs_path,
void *value, size_t size)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = flistxattr(fd, value, size);
close(fd);
return ret;
}
static int handle_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
void *value, size_t size, int flags)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = fsetxattr(fd, name, value, size, flags);
close(fd);
return ret;
}
static int handle_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
const char *name)
{
int fd, ret;
HandleData *data = (HandleData *) ctx->private;
fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
if (fd < 0) {
return fd;
}
ret = fremovexattr(fd, name);
close(fd);
return ret;
}
static int handle_name_to_path(FsContext *ctx, V9fsPath *dir_path,
const char *name, V9fsPath *target)
{
char *buffer;
struct file_handle *fh;
int dirfd, ret, mnt_id;
HandleData *data = (HandleData *) ctx->private;
/* "." and ".." are not allowed */
if (!strcmp(name, ".") || !strcmp(name, "..")) {
errno = EINVAL;
return -1;
}
if (dir_path) {
dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
} else {
/* relative to export root */
buffer = rpath(ctx, ".");
dirfd = open(buffer, O_DIRECTORY);
g_free(buffer);
}
if (dirfd < 0) {
return dirfd;
}
fh = g_malloc(sizeof(struct file_handle) + data->handle_bytes);
fh->handle_bytes = data->handle_bytes;
/* add a "./" at the beginning of the path */
buffer = g_strdup_printf("./%s", name);
/* flag = 0 imply don't follow symlink */
ret = name_to_handle(dirfd, buffer, fh, &mnt_id, 0);
if (!ret) {
target->data = (char *)fh;
target->size = sizeof(struct file_handle) + data->handle_bytes;
} else {
g_free(fh);
}
close(dirfd);
g_free(buffer);
return ret;
}
static int handle_renameat(FsContext *ctx, V9fsPath *olddir,
const char *old_name, V9fsPath *newdir,
const char *new_name)
{
int olddirfd, newdirfd, ret;
HandleData *data = (HandleData *) ctx->private;
olddirfd = open_by_handle(data->mountfd, olddir->data, O_PATH);
if (olddirfd < 0) {
return olddirfd;
}
newdirfd = open_by_handle(data->mountfd, newdir->data, O_PATH);
if (newdirfd < 0) {
close(olddirfd);
return newdirfd;
}
ret = renameat(olddirfd, old_name, newdirfd, new_name);
close(newdirfd);
close(olddirfd);
return ret;
}
static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
const char *name, int flags)
{
int dirfd, ret;
HandleData *data = (HandleData *) ctx->private;
dirfd = open_by_handle(data->mountfd, dir->data, O_PATH);
if (dirfd < 0) {
return dirfd;
}
ret = unlinkat(dirfd, name, flags);
close(dirfd);
return ret;
}
static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
mode_t st_mode, uint64_t *st_gen)
{
#ifdef FS_IOC_GETVERSION
int err;
V9fsFidOpenState fid_open;
/*
* Do not try to open special files like device nodes, fifos etc
* We can get fd for regular files and directories only
*/
if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
errno = ENOTTY;
return -1;
}
err = handle_open(ctx, path, O_RDONLY, &fid_open);
if (err < 0) {
return err;
}
err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
handle_close(ctx, &fid_open);
return err;
#else
errno = ENOTTY;
return -1;
#endif
}
static int handle_init(FsContext *ctx, Error **errp)
{
int ret, mnt_id;
struct statfs stbuf;
struct file_handle fh;
HandleData *data = g_malloc(sizeof(HandleData));
data->mountfd = open(ctx->fs_root, O_DIRECTORY);
if (data->mountfd < 0) {
ret = data->mountfd;
goto err_out;
}
ret = statfs(ctx->fs_root, &stbuf);
if (!ret) {
switch (stbuf.f_type) {
case EXT2_SUPER_MAGIC:
case BTRFS_SUPER_MAGIC:
case REISERFS_SUPER_MAGIC:
case XFS_SUPER_MAGIC:
ctx->exops.get_st_gen = handle_ioc_getversion;
break;
}
}
memset(&fh, 0, sizeof(struct file_handle));
ret = name_to_handle(data->mountfd, ".", &fh, &mnt_id, 0);
if (ret && errno == EOVERFLOW) {
data->handle_bytes = fh.handle_bytes;
ctx->private = data;
ret = 0;
goto out;
}
/* we got 0 byte handle ? */
ret = -1;
close(data->mountfd);
err_out:
g_free(data);
out:
return ret;
}
static void handle_cleanup(FsContext *ctx)
{
HandleData *data = ctx->private;
close(data->mountfd);
g_free(data);
}
static int handle_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
{
const char *sec_model = qemu_opt_get(opts, "security_model");
const char *path = qemu_opt_get(opts, "path");
warn_report("handle backend is deprecated");
if (sec_model) {
error_setg(errp,
"Invalid argument security_model specified with handle fsdriver");
return -1;
}
if (!path) {
error_setg(errp, "fsdev: No path specified");
return -1;
}
fse->path = g_strdup(path);
return 0;
}
FileOperations handle_ops = {
.parse_opts = handle_parse_opts,
.init = handle_init,
.cleanup = handle_cleanup,
.lstat = handle_lstat,
.readlink = handle_readlink,
.close = handle_close,
.closedir = handle_closedir,
.open = handle_open,
.opendir = handle_opendir,
.rewinddir = handle_rewinddir,
.telldir = handle_telldir,
.readdir = handle_readdir,
.seekdir = handle_seekdir,
.preadv = handle_preadv,
.pwritev = handle_pwritev,
.chmod = handle_chmod,
.mknod = handle_mknod,
.mkdir = handle_mkdir,
.fstat = handle_fstat,
.open2 = handle_open2,
.symlink = handle_symlink,
.link = handle_link,
.truncate = handle_truncate,
.rename = handle_rename,
.chown = handle_chown,
.utimensat = handle_utimensat,
.remove = handle_remove,
.fsync = handle_fsync,
.statfs = handle_statfs,
.lgetxattr = handle_lgetxattr,
.llistxattr = handle_llistxattr,
.lsetxattr = handle_lsetxattr,
.lremovexattr = handle_lremovexattr,
.name_to_path = handle_name_to_path,
.renameat = handle_renameat,
.unlinkat = handle_unlinkat,
};

1
hw/9pfs/Makefile.objs
View File

@ -4,7 +4,6 @@ common-obj-y += 9p-local.o 9p-xattr.o
common-obj-y += 9p-xattr-user.o 9p-posix-acl.o
common-obj-y += coth.o cofs.o codir.o cofile.o
common-obj-y += coxattr.o 9p-synth.o
common-obj-$(CONFIG_OPEN_BY_HANDLE) += 9p-handle.o
common-obj-y += 9p-proxy.o
endif

8
qemu-deprecated.texi
View File

@ -46,14 +46,6 @@ would automatically enable USB support on the machine type.
If using the new syntax, USB support must be explicitly
enabled via the ``-machine usb=on'' argument.
@subsection -fsdev handle (since 2.12.0)
The ``handle'' fsdev backend does not support symlinks and causes the 9p
filesystem in the guest to fail a fair amount of tests from the PJD POSIX
filesystem test suite. Also it requires the CAP_DAC_READ_SEARCH capability,
which is not the recommended way to run QEMU. This backend should not be
used and it will be removed with no replacement.
@subsection -no-frame (since 2.12.0)
The @code{--no-frame} argument works with SDL 1.2 only. The other user

8
qemu-options.hx
View File

@ -1019,7 +1019,7 @@ Define a new file system device. Valid options are:
@table @option
@item @var{fsdriver}
This option specifies the fs driver backend to use.
Currently "local", "handle" and "proxy" file system drivers are supported.
Currently "local" and "proxy" file system drivers are supported.
@item id=@var{id}
Specifies identifier for this device
@item path=@var{path}
@ -1037,7 +1037,7 @@ hidden .virtfs_metadata directory. Directories exported by this security model c
interact with other unix tools. "none" security model is same as
passthrough except the sever won't report failures if it fails to
set file attributes like ownership. Security model is mandatory
only for local fsdriver. Other fsdrivers (like handle, proxy) don't take
only for local fsdriver. Other fsdrivers (like proxy) don't take
security model as a parameter.
@item writeout=@var{writeout}
This is an optional argument. The only supported value is "immediate".
@ -1088,7 +1088,7 @@ The general form of a Virtual File system pass-through options are:
@table @option
@item @var{fsdriver}
This option specifies the fs driver backend to use.
Currently "local", "handle" and "proxy" file system drivers are supported.
Currently "local" and "proxy" file system drivers are supported.
@item id=@var{id}
Specifies identifier for this device
@item path=@var{path}
@ -1106,7 +1106,7 @@ hidden .virtfs_metadata directory. Directories exported by this security model c
interact with other unix tools. "none" security model is same as
passthrough except the sever won't report failures if it fails to
set file attributes like ownership. Security model is mandatory only
for local fsdriver. Other fsdrivers (like handle, proxy) don't take security
for local fsdriver. Other fsdrivers (like proxy) don't take security
model as a parameter.
@item writeout=@var{writeout}
This is an optional argument. The only supported value is "immediate".