Add new proxy filesystem driver to add root privilege to qemu process. It needs a helper process to be started by root user. Following command line can be used to utilize proxy filesystem driver -virtfs proxy,id=<id>,mount_tag=<tag>,socket_fd=<socket-fd> Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
389 lines
9.5 KiB
C
389 lines
9.5 KiB
C
/*
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* Virtio 9p Proxy callback
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*
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* Copyright IBM, Corp. 2011
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*
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* Authors:
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* M. Mohan Kumar <mohan@in.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include <sys/socket.h>
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#include <sys/un.h>
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#include "hw/virtio.h"
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#include "virtio-9p.h"
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#include "fsdev/qemu-fsdev.h"
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#include "virtio-9p-proxy.h"
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typedef struct V9fsProxy {
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int sockfd;
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QemuMutex mutex;
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struct iovec iovec;
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} V9fsProxy;
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static int proxy_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static ssize_t proxy_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
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char *buf, size_t bufsz)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_close(FsContext *ctx, V9fsFidOpenState *fs)
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{
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return close(fs->fd);
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}
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static int proxy_closedir(FsContext *ctx, V9fsFidOpenState *fs)
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{
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return closedir(fs->dir);
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}
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static int proxy_open(FsContext *ctx, V9fsPath *fs_path,
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int flags, V9fsFidOpenState *fs)
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{
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fs->fd = -1;
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return fs->fd;
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}
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static int proxy_opendir(FsContext *ctx,
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V9fsPath *fs_path, V9fsFidOpenState *fs)
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{
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fs->dir = NULL;
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errno = EOPNOTSUPP;
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return -1;
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}
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static void proxy_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
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{
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return rewinddir(fs->dir);
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}
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static off_t proxy_telldir(FsContext *ctx, V9fsFidOpenState *fs)
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{
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return telldir(fs->dir);
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}
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static int proxy_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
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struct dirent *entry,
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struct dirent **result)
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{
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return readdir_r(fs->dir, entry, result);
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}
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static void proxy_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
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{
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return seekdir(fs->dir, off);
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}
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static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
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const struct iovec *iov,
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int iovcnt, off_t offset)
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{
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#ifdef CONFIG_PREADV
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return preadv(fs->fd, iov, iovcnt, offset);
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#else
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int err = lseek(fs->fd, offset, SEEK_SET);
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if (err == -1) {
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return err;
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} else {
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return readv(fs->fd, iov, iovcnt);
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}
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#endif
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}
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static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
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const struct iovec *iov,
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int iovcnt, off_t offset)
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{
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ssize_t ret;
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#ifdef CONFIG_PREADV
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ret = pwritev(fs->fd, iov, iovcnt, offset);
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#else
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int err = lseek(fs->fd, offset, SEEK_SET);
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if (err == -1) {
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return err;
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} else {
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ret = writev(fs->fd, iov, iovcnt);
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}
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#endif
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#ifdef CONFIG_SYNC_FILE_RANGE
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if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
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/*
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* Initiate a writeback. This is not a data integrity sync.
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* We want to ensure that we don't leave dirty pages in the cache
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* after write when writeout=immediate is sepcified.
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*/
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sync_file_range(fs->fd, offset, ret,
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SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
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}
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#endif
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return ret;
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}
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static int proxy_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
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const char *name, FsCred *credp)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
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const char *name, FsCred *credp)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_fstat(FsContext *fs_ctx, int fid_type,
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V9fsFidOpenState *fs, struct stat *stbuf)
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{
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int fd;
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if (fid_type == P9_FID_DIR) {
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fd = dirfd(fs->dir);
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} else {
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fd = fs->fd;
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}
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return fstat(fd, stbuf);
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}
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static int proxy_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
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int flags, FsCred *credp, V9fsFidOpenState *fs)
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{
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fs->fd = -1;
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_symlink(FsContext *fs_ctx, const char *oldpath,
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V9fsPath *dir_path, const char *name, FsCred *credp)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_link(FsContext *ctx, V9fsPath *oldpath,
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V9fsPath *dirpath, const char *name)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_rename(FsContext *ctx, const char *oldpath,
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const char *newpath)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_utimensat(FsContext *s, V9fsPath *fs_path,
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const struct timespec *buf)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_remove(FsContext *ctx, const char *path)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_fsync(FsContext *ctx, int fid_type,
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V9fsFidOpenState *fs, int datasync)
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{
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int fd;
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if (fid_type == P9_FID_DIR) {
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fd = dirfd(fs->dir);
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} else {
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fd = fs->fd;
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}
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if (datasync) {
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return qemu_fdatasync(fd);
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} else {
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return fsync(fd);
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}
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}
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static int proxy_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static ssize_t proxy_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
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const char *name, void *value, size_t size)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static ssize_t proxy_llistxattr(FsContext *ctx, V9fsPath *fs_path,
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void *value, size_t size)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
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void *value, size_t size, int flags)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
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const char *name)
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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static int proxy_name_to_path(FsContext *ctx, V9fsPath *dir_path,
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const char *name, V9fsPath *target)
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{
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if (dir_path) {
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v9fs_string_sprintf((V9fsString *)target, "%s/%s",
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dir_path->data, name);
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} else {
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v9fs_string_sprintf((V9fsString *)target, "%s", name);
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}
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/* Bump the size for including terminating NULL */
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target->size++;
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return 0;
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}
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static int proxy_renameat(FsContext *ctx, V9fsPath *olddir,
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const char *old_name, V9fsPath *newdir,
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const char *new_name)
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{
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int ret;
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V9fsString old_full_name, new_full_name;
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v9fs_string_init(&old_full_name);
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v9fs_string_init(&new_full_name);
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v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
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v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
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ret = proxy_rename(ctx, old_full_name.data, new_full_name.data);
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v9fs_string_free(&old_full_name);
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v9fs_string_free(&new_full_name);
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return ret;
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}
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static int proxy_unlinkat(FsContext *ctx, V9fsPath *dir,
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const char *name, int flags)
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{
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int ret;
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V9fsString fullname;
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v9fs_string_init(&fullname);
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v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
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ret = proxy_remove(ctx, fullname.data);
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v9fs_string_free(&fullname);
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return ret;
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}
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static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs)
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{
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const char *sock_fd = qemu_opt_get(opts, "sock_fd");
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if (sock_fd) {
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fprintf(stderr, "sock_fd option not specified\n");
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return -1;
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}
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fs->path = g_strdup(sock_fd);
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return 0;
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}
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static int proxy_init(FsContext *ctx)
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{
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V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy));
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int sock_id;
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sock_id = atoi(ctx->fs_root);
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if (sock_id < 0) {
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fprintf(stderr, "socket descriptor not initialized\n");
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return -1;
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}
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g_free(ctx->fs_root);
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proxy->iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
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proxy->iovec.iov_len = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
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ctx->private = proxy;
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proxy->sockfd = sock_id;
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qemu_mutex_init(&proxy->mutex);
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ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
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return 0;
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}
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FileOperations proxy_ops = {
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.parse_opts = proxy_parse_opts,
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.init = proxy_init,
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.lstat = proxy_lstat,
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.readlink = proxy_readlink,
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.close = proxy_close,
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.closedir = proxy_closedir,
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.open = proxy_open,
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.opendir = proxy_opendir,
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.rewinddir = proxy_rewinddir,
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.telldir = proxy_telldir,
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.readdir_r = proxy_readdir_r,
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.seekdir = proxy_seekdir,
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.preadv = proxy_preadv,
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.pwritev = proxy_pwritev,
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.chmod = proxy_chmod,
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.mknod = proxy_mknod,
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.mkdir = proxy_mkdir,
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.fstat = proxy_fstat,
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.open2 = proxy_open2,
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.symlink = proxy_symlink,
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.link = proxy_link,
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.truncate = proxy_truncate,
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.rename = proxy_rename,
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.chown = proxy_chown,
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.utimensat = proxy_utimensat,
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.remove = proxy_remove,
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.fsync = proxy_fsync,
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.statfs = proxy_statfs,
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.lgetxattr = proxy_lgetxattr,
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.llistxattr = proxy_llistxattr,
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.lsetxattr = proxy_lsetxattr,
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.lremovexattr = proxy_lremovexattr,
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.name_to_path = proxy_name_to_path,
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.renameat = proxy_renameat,
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.unlinkat = proxy_unlinkat,
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};
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