/* * 9p Posix callback * * Copyright IBM, Corp. 2010 * * Authors: * Anthony Liguori * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. */ /* * Not so fast! You might want to read the 9p developer docs first: * https://wiki.qemu.org/Documentation/9p */ #include "qemu/osdep.h" #include "9p.h" #include "9p-local.h" #include "9p-xattr.h" #include "9p-util.h" #include "fsdev/qemu-fsdev.h" /* local_ops */ #include #include #include #include #include #include "qemu/xattr.h" #include "qapi/error.h" #include "qemu/cutils.h" #include "qemu/error-report.h" #include "qemu/option.h" #include #ifdef CONFIG_LINUX #include #ifdef CONFIG_LINUX_MAGIC_H #include #endif #endif #include #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 { int mountfd; } LocalData; int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags, mode_t mode) { LocalData *data = fs_ctx->private; int fd = data->mountfd; while (*path && fd != -1) { const char *c; int next_fd; char *head; /* Only relative paths without consecutive slashes */ assert(*path != '/'); head = g_strdup(path); c = qemu_strchrnul(path, '/'); if (*c) { /* Intermediate path element */ head[c - path] = 0; path = c + 1; next_fd = openat_dir(fd, head); } else { /* Rightmost path element */ next_fd = openat_file(fd, head, flags, mode); path = c; } g_free(head); if (fd != data->mountfd) { close_preserve_errno(fd); } fd = next_fd; } assert(fd != data->mountfd); return fd; } int local_opendir_nofollow(FsContext *fs_ctx, const char *path) { return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0); } static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd, const char *npath) { int serrno = errno; qemu_renameat(odirfd, opath, ndirfd, npath); errno = serrno; } static void unlinkat_preserve_errno(int dirfd, const char *path, int flags) { int serrno = errno; qemu_unlinkat(dirfd, path, flags); errno = serrno; } #define VIRTFS_META_DIR ".virtfs_metadata" #define VIRTFS_META_ROOT_FILE VIRTFS_META_DIR "_root" static FILE *local_fopenat(int dirfd, const char *name, const char *mode) { int fd, o_mode = 0; FILE *fp; int flags; /* * only supports two modes */ if (mode[0] == 'r') { flags = O_RDONLY; } else if (mode[0] == 'w') { flags = O_WRONLY | O_TRUNC | O_CREAT; o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH; } else { return NULL; } fd = openat_file(dirfd, name, flags, o_mode); if (fd == -1) { return NULL; } fp = fdopen(fd, mode); if (!fp) { close(fd); } return fp; } #define ATTR_MAX 100 static void local_mapped_file_attr(int dirfd, const char *name, struct stat *stbuf) { FILE *fp; char buf[ATTR_MAX]; int map_dirfd; if (strcmp(name, ".")) { map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); if (map_dirfd == -1) { return; } fp = local_fopenat(map_dirfd, name, "r"); close_preserve_errno(map_dirfd); } else { fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r"); } if (!fp) { return; } memset(buf, 0, ATTR_MAX); while (fgets(buf, ATTR_MAX, fp)) { if (!strncmp(buf, "virtfs.uid", 10)) { stbuf->st_uid = atoi(buf + 11); } else if (!strncmp(buf, "virtfs.gid", 10)) { stbuf->st_gid = atoi(buf + 11); } else if (!strncmp(buf, "virtfs.mode", 11)) { stbuf->st_mode = atoi(buf + 12); } else if (!strncmp(buf, "virtfs.rdev", 11)) { stbuf->st_rdev = atoi(buf + 12); } memset(buf, 0, ATTR_MAX); } fclose(fp); } static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf) { int err = -1; char *dirpath = g_path_get_dirname(fs_path->data); char *name = g_path_get_basename(fs_path->data); int dirfd; dirfd = local_opendir_nofollow(fs_ctx, dirpath); if (dirfd == -1) { goto out; } err = qemu_fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW); if (err) { goto err_out; } if (fs_ctx->export_flags & V9FS_SM_MAPPED) { /* Actual credentials are part of extended attrs */ uid_t tmp_uid; gid_t tmp_gid; mode_t tmp_mode; dev_t tmp_dev; if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) { stbuf->st_uid = le32_to_cpu(tmp_uid); } if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) { stbuf->st_gid = le32_to_cpu(tmp_gid); } if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) { stbuf->st_mode = le32_to_cpu(tmp_mode); } if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) { stbuf->st_rdev = le64_to_cpu(tmp_dev); } } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { local_mapped_file_attr(dirfd, name, stbuf); } err_out: close_preserve_errno(dirfd); out: g_free(name); g_free(dirpath); return err; } static int local_set_mapped_file_attrat(int dirfd, const char *name, FsCred *credp) { FILE *fp; int ret; char buf[ATTR_MAX]; int uid = -1, gid = -1, mode = -1, rdev = -1; int map_dirfd = -1, map_fd; bool is_root = !strcmp(name, "."); if (is_root) { fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r"); if (!fp) { if (errno == ENOENT) { goto update_map_file; } else { return -1; } } } else { ret = qemu_mkdirat(dirfd, VIRTFS_META_DIR, 0700); if (ret < 0 && errno != EEXIST) { return -1; } map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); if (map_dirfd == -1) { return -1; } fp = local_fopenat(map_dirfd, name, "r"); if (!fp) { if (errno == ENOENT) { goto update_map_file; } else { close_preserve_errno(map_dirfd); return -1; } } } memset(buf, 0, ATTR_MAX); while (fgets(buf, ATTR_MAX, fp)) { if (!strncmp(buf, "virtfs.uid", 10)) { uid = atoi(buf + 11); } else if (!strncmp(buf, "virtfs.gid", 10)) { gid = atoi(buf + 11); } else if (!strncmp(buf, "virtfs.mode", 11)) { mode = atoi(buf + 12); } else if (!strncmp(buf, "virtfs.rdev", 11)) { rdev = atoi(buf + 12); } memset(buf, 0, ATTR_MAX); } fclose(fp); update_map_file: if (is_root) { fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "w"); } else { fp = local_fopenat(map_dirfd, name, "w"); /* We can't go this far with map_dirfd not being a valid file descriptor * but some versions of gcc aren't smart enough to see it. */ if (map_dirfd != -1) { close_preserve_errno(map_dirfd); } } if (!fp) { return -1; } map_fd = fileno(fp); assert(map_fd != -1); ret = fchmod(map_fd, 0600); assert(ret == 0); if (credp->fc_uid != -1) { uid = credp->fc_uid; } if (credp->fc_gid != -1) { gid = credp->fc_gid; } if (credp->fc_mode != (mode_t)-1) { mode = credp->fc_mode; } if (credp->fc_rdev != -1) { rdev = credp->fc_rdev; } if (uid != -1) { fprintf(fp, "virtfs.uid=%d\n", uid); } if (gid != -1) { fprintf(fp, "virtfs.gid=%d\n", gid); } if (mode != -1) { fprintf(fp, "virtfs.mode=%d\n", mode); } if (rdev != -1) { fprintf(fp, "virtfs.rdev=%d\n", rdev); } fclose(fp); return 0; } static int fchmodat_nofollow(int dirfd, const char *name, mode_t mode) { struct stat stbuf; int fd, ret; /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW). * Unfortunately, the linux kernel doesn't implement it yet. */ /* First, we clear non-racing symlinks out of the way. */ if (qemu_fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW)) { return -1; } if (S_ISLNK(stbuf.st_mode)) { errno = ELOOP; return -1; } fd = openat_file(dirfd, name, O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0); #if O_PATH_9P_UTIL == 0 /* Fallback for systems that don't support O_PATH: we depend on the file * being readable or writable. */ if (fd == -1) { /* In case the file is writable-only and isn't a directory. */ if (errno == EACCES) { fd = openat_file(dirfd, name, O_WRONLY, 0); } if (fd == -1 && errno == EISDIR) { errno = EACCES; } } if (fd == -1) { return -1; } ret = fchmod(fd, mode); #else /* Access modes are ignored when O_PATH is supported. If name is a symbolic * link, O_PATH | O_NOFOLLOW causes openat(2) to return a file descriptor * referring to the symbolic link. */ if (fd == -1) { return -1; } /* Now we handle racing symlinks. */ ret = fstat(fd, &stbuf); if (!ret) { if (S_ISLNK(stbuf.st_mode)) { errno = ELOOP; ret = -1; } else { char *proc_path = g_strdup_printf("/proc/self/fd/%d", fd); ret = chmod(proc_path, mode); g_free(proc_path); } } #endif close_preserve_errno(fd); return ret; } static int local_set_xattrat(int dirfd, const char *path, FsCred *credp) { int err; if (credp->fc_uid != -1) { uint32_t tmp_uid = cpu_to_le32(credp->fc_uid); err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid, sizeof(uid_t), 0); if (err) { return err; } } if (credp->fc_gid != -1) { uint32_t tmp_gid = cpu_to_le32(credp->fc_gid); err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid, sizeof(gid_t), 0); if (err) { return err; } } if (credp->fc_mode != (mode_t)-1) { uint32_t tmp_mode = cpu_to_le32(credp->fc_mode); err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode, sizeof(mode_t), 0); if (err) { return err; } } if (credp->fc_rdev != -1) { uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev); err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev, sizeof(dev_t), 0); if (err) { return err; } } return 0; } static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd, const char *name, FsCred *credp) { if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, AT_SYMLINK_NOFOLLOW) < 0) { /* * If we fail to change ownership and if we are * using security model none. Ignore the error */ if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) { return -1; } } return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777); } static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path, char *buf, size_t bufsz) { ssize_t tsize = -1; if ((fs_ctx->export_flags & V9FS_SM_MAPPED) || (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) { int fd; fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0); if (fd == -1) { return -1; } do { tsize = read(fd, (void *)buf, bufsz); } while (tsize == -1 && errno == EINTR); close_preserve_errno(fd); } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || (fs_ctx->export_flags & V9FS_SM_NONE)) { char *dirpath = g_path_get_dirname(fs_path->data); char *name = g_path_get_basename(fs_path->data); int dirfd; dirfd = local_opendir_nofollow(fs_ctx, dirpath); if (dirfd == -1) { goto out; } tsize = readlinkat(dirfd, name, buf, bufsz); close_preserve_errno(dirfd); out: g_free(name); g_free(dirpath); } return tsize; } static int local_close(FsContext *ctx, V9fsFidOpenState *fs) { return close(fs->fd); } static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs) { return closedir(fs->dir.stream); } static int local_open(FsContext *ctx, V9fsPath *fs_path, int flags, V9fsFidOpenState *fs) { int fd; fd = local_open_nofollow(ctx, fs_path->data, flags, 0); if (fd == -1) { return -1; } fs->fd = fd; return fs->fd; } static int local_opendir(FsContext *ctx, V9fsPath *fs_path, V9fsFidOpenState *fs) { int dirfd; DIR *stream; dirfd = local_opendir_nofollow(ctx, fs_path->data); if (dirfd == -1) { return -1; } stream = fdopendir(dirfd); if (!stream) { close(dirfd); return -1; } fs->dir.stream = stream; return 0; } static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) { rewinddir(fs->dir.stream); } static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs) { return telldir(fs->dir.stream); } static bool local_is_mapped_file_metadata(FsContext *fs_ctx, const char *name) { return !strcmp(name, VIRTFS_META_DIR) || !strcmp(name, VIRTFS_META_ROOT_FILE); } static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs) { struct dirent *entry; again: entry = readdir(fs->dir.stream); if (!entry) { return NULL; } #ifdef CONFIG_DARWIN int off; off = telldir(fs->dir.stream); /* If telldir fails, fail the entire readdir call */ if (off < 0) { return NULL; } entry->d_seekoff = off; #endif if (ctx->export_flags & V9FS_SM_MAPPED) { entry->d_type = DT_UNKNOWN; } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { if (local_is_mapped_file_metadata(ctx, entry->d_name)) { /* skip the meta data */ goto again; } entry->d_type = DT_UNKNOWN; } return entry; } static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) { seekdir(fs->dir.stream, off); } static ssize_t local_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 local_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 local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) { char *dirpath = g_path_get_dirname(fs_path->data); char *name = g_path_get_basename(fs_path->data); int ret = -1; int dirfd; dirfd = local_opendir_nofollow(fs_ctx, dirpath); if (dirfd == -1) { goto out; } if (fs_ctx->export_flags & V9FS_SM_MAPPED) { ret = local_set_xattrat(dirfd, name, credp); } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { ret = local_set_mapped_file_attrat(dirfd, name, credp); } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || fs_ctx->export_flags & V9FS_SM_NONE) { ret = fchmodat_nofollow(dirfd, name, credp->fc_mode); } close_preserve_errno(dirfd); out: g_free(dirpath); g_free(name); return ret; } static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, FsCred *credp) { int err = -1; int dirfd; if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(fs_ctx, name)) { errno = EINVAL; return -1; } dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); if (dirfd == -1) { return -1; } if (fs_ctx->export_flags & V9FS_SM_MAPPED || fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { err = qemu_mknodat(dirfd, name, fs_ctx->fmode | S_IFREG, 0); if (err == -1) { goto out; } if (fs_ctx->export_flags & V9FS_SM_MAPPED) { err = local_set_xattrat(dirfd, name, credp); } else { err = local_set_mapped_file_attrat(dirfd, name, credp); } if (err == -1) { goto err_end; } } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || fs_ctx->export_flags & V9FS_SM_NONE) { err = qemu_mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev); if (err == -1) { goto out; } err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); if (err == -1) { goto err_end; } } goto out; err_end: unlinkat_preserve_errno(dirfd, name, 0); out: close_preserve_errno(dirfd); return err; } static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, FsCred *credp) { int err = -1; int dirfd; if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(fs_ctx, name)) { errno = EINVAL; return -1; } dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); if (dirfd == -1) { return -1; } if (fs_ctx->export_flags & V9FS_SM_MAPPED || fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { err = qemu_mkdirat(dirfd, name, fs_ctx->dmode); if (err == -1) { goto out; } credp->fc_mode = credp->fc_mode | S_IFDIR; if (fs_ctx->export_flags & V9FS_SM_MAPPED) { err = local_set_xattrat(dirfd, name, credp); } else { err = local_set_mapped_file_attrat(dirfd, name, credp); } if (err == -1) { goto err_end; } } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || fs_ctx->export_flags & V9FS_SM_NONE) { err = qemu_mkdirat(dirfd, name, credp->fc_mode); if (err == -1) { goto out; } err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); if (err == -1) { goto err_end; } } goto out; err_end: unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR); out: close_preserve_errno(dirfd); return err; } static int local_fstat(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs, struct stat *stbuf) { int err, fd; if (fid_type == P9_FID_DIR) { fd = dirfd(fs->dir.stream); } else { fd = fs->fd; } err = fstat(fd, stbuf); if (err) { return err; } if (fs_ctx->export_flags & V9FS_SM_MAPPED) { /* Actual credentials are part of extended attrs */ uid_t tmp_uid; gid_t tmp_gid; mode_t tmp_mode; dev_t tmp_dev; if (qemu_fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) { stbuf->st_uid = le32_to_cpu(tmp_uid); } if (qemu_fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) { stbuf->st_gid = le32_to_cpu(tmp_gid); } if (qemu_fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) { stbuf->st_mode = le32_to_cpu(tmp_mode); } if (qemu_fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) { stbuf->st_rdev = le64_to_cpu(tmp_dev); } } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { errno = EOPNOTSUPP; return -1; } return err; } static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, int flags, FsCred *credp, V9fsFidOpenState *fs) { int fd = -1; int err = -1; int dirfd; if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(fs_ctx, name)) { errno = EINVAL; return -1; } /* * Mark all the open to not follow symlinks */ flags |= O_NOFOLLOW; dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); if (dirfd == -1) { return -1; } /* Determine the security model */ if (fs_ctx->export_flags & V9FS_SM_MAPPED || fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { fd = openat_file(dirfd, name, flags, fs_ctx->fmode); if (fd == -1) { goto out; } credp->fc_mode = credp->fc_mode | S_IFREG; if (fs_ctx->export_flags & V9FS_SM_MAPPED) { /* Set cleint credentials in xattr */ err = local_set_xattrat(dirfd, name, credp); } else { err = local_set_mapped_file_attrat(dirfd, name, credp); } if (err == -1) { goto err_end; } } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || (fs_ctx->export_flags & V9FS_SM_NONE)) { fd = openat_file(dirfd, name, flags, credp->fc_mode); if (fd == -1) { goto out; } err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); if (err == -1) { goto err_end; } } err = fd; fs->fd = fd; goto out; err_end: unlinkat_preserve_errno(dirfd, name, flags & O_DIRECTORY ? AT_REMOVEDIR : 0); close_preserve_errno(fd); out: close_preserve_errno(dirfd); return err; } static int local_symlink(FsContext *fs_ctx, const char *oldpath, V9fsPath *dir_path, const char *name, FsCred *credp) { int err = -1; int dirfd; if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(fs_ctx, name)) { errno = EINVAL; return -1; } dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); if (dirfd == -1) { return -1; } /* Determine the security model */ if (fs_ctx->export_flags & V9FS_SM_MAPPED || fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { int fd; ssize_t oldpath_size, write_size; fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR, fs_ctx->fmode); if (fd == -1) { goto out; } /* Write the oldpath (target) to the file. */ oldpath_size = strlen(oldpath); do { write_size = write(fd, (void *)oldpath, oldpath_size); } while (write_size == -1 && errno == EINTR); close_preserve_errno(fd); if (write_size != oldpath_size) { goto err_end; } /* Set cleint credentials in symlink's xattr */ credp->fc_mode = credp->fc_mode | S_IFLNK; if (fs_ctx->export_flags & V9FS_SM_MAPPED) { err = local_set_xattrat(dirfd, name, credp); } else { err = local_set_mapped_file_attrat(dirfd, name, credp); } if (err == -1) { goto err_end; } } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || fs_ctx->export_flags & V9FS_SM_NONE) { err = symlinkat(oldpath, dirfd, name); if (err) { goto out; } err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, AT_SYMLINK_NOFOLLOW); if (err == -1) { /* * If we fail to change ownership and if we are * using security model none. Ignore the error */ if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) { goto err_end; } else { err = 0; } } } goto out; err_end: unlinkat_preserve_errno(dirfd, name, 0); out: close_preserve_errno(dirfd); return err; } static int local_link(FsContext *ctx, V9fsPath *oldpath, V9fsPath *dirpath, const char *name) { char *odirpath = g_path_get_dirname(oldpath->data); char *oname = g_path_get_basename(oldpath->data); int ret = -1; int odirfd, ndirfd; if (ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(ctx, name)) { errno = EINVAL; goto out; } odirfd = local_opendir_nofollow(ctx, odirpath); if (odirfd == -1) { goto out; } ndirfd = local_opendir_nofollow(ctx, dirpath->data); if (ndirfd == -1) { close_preserve_errno(odirfd); goto out; } ret = linkat(odirfd, oname, ndirfd, name, 0); if (ret < 0) { goto out_close; } /* now link the virtfs_metadata files */ if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { int omap_dirfd, nmap_dirfd; ret = qemu_mkdirat(ndirfd, VIRTFS_META_DIR, 0700); if (ret < 0 && errno != EEXIST) { goto err_undo_link; } omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); if (omap_dirfd == -1) { goto err; } nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); if (nmap_dirfd == -1) { close_preserve_errno(omap_dirfd); goto err; } ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0); close_preserve_errno(nmap_dirfd); close_preserve_errno(omap_dirfd); if (ret < 0 && errno != ENOENT) { goto err_undo_link; } ret = 0; } goto out_close; err: ret = -1; err_undo_link: unlinkat_preserve_errno(ndirfd, name, 0); out_close: close_preserve_errno(ndirfd); close_preserve_errno(odirfd); out: g_free(oname); g_free(odirpath); return ret; } static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size) { int fd, ret; fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0); if (fd == -1) { return -1; } ret = ftruncate(fd, size); close_preserve_errno(fd); return ret; } static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) { char *dirpath = g_path_get_dirname(fs_path->data); char *name = g_path_get_basename(fs_path->data); int ret = -1; int dirfd; dirfd = local_opendir_nofollow(fs_ctx, dirpath); if (dirfd == -1) { goto out; } if ((credp->fc_uid == -1 && credp->fc_gid == -1) || (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || (fs_ctx->export_flags & V9FS_SM_NONE)) { ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, AT_SYMLINK_NOFOLLOW); } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) { ret = local_set_xattrat(dirfd, name, credp); } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { ret = local_set_mapped_file_attrat(dirfd, name, credp); } close_preserve_errno(dirfd); out: g_free(name); g_free(dirpath); return ret; } static int local_utimensat(FsContext *s, V9fsPath *fs_path, const struct timespec *buf) { char *dirpath = g_path_get_dirname(fs_path->data); char *name = g_path_get_basename(fs_path->data); int dirfd, ret = -1; dirfd = local_opendir_nofollow(s, dirpath); if (dirfd == -1) { goto out; } ret = qemu_utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW); close_preserve_errno(dirfd); out: g_free(dirpath); g_free(name); return ret; } static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, int flags) { int ret; if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { int map_dirfd; /* We need to remove the metadata as well: * - the metadata directory if we're removing a directory * - the metadata file in the parent's metadata directory * * If any of these are missing (ie, ENOENT) then we're probably * trying to remove something that wasn't created in mapped-file * mode. We just ignore the error. */ if (flags == AT_REMOVEDIR) { int fd; fd = openat_dir(dirfd, name); if (fd == -1) { return -1; } ret = qemu_unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); close_preserve_errno(fd); if (ret < 0 && errno != ENOENT) { return -1; } } map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); if (map_dirfd != -1) { ret = qemu_unlinkat(map_dirfd, name, 0); close_preserve_errno(map_dirfd); if (ret < 0 && errno != ENOENT) { return -1; } } else if (errno != ENOENT) { return -1; } } return qemu_unlinkat(dirfd, name, flags); } static int local_remove(FsContext *ctx, const char *path) { struct stat stbuf; char *dirpath = g_path_get_dirname(path); char *name = g_path_get_basename(path); int flags = 0; int dirfd; int err = -1; dirfd = local_opendir_nofollow(ctx, dirpath); if (dirfd == -1) { goto out; } if (qemu_fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) { goto err_out; } if (S_ISDIR(stbuf.st_mode)) { flags |= AT_REMOVEDIR; } err = local_unlinkat_common(ctx, dirfd, name, flags); err_out: close_preserve_errno(dirfd); out: g_free(name); g_free(dirpath); return err; } static int local_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 local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) { int fd, ret; fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0); if (fd == -1) { return -1; } ret = fstatfs(fd, stbuf); close_preserve_errno(fd); return ret; } static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name, void *value, size_t size) { char *path = fs_path->data; return v9fs_get_xattr(ctx, path, name, value, size); } static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path, void *value, size_t size) { char *path = fs_path->data; return v9fs_list_xattr(ctx, path, value, size); } static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name, void *value, size_t size, int flags) { char *path = fs_path->data; return v9fs_set_xattr(ctx, path, name, value, size, flags); } static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path, const char *name) { char *path = fs_path->data; return v9fs_remove_xattr(ctx, path, name); } static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path, const char *name, V9fsPath *target) { if (ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(ctx, name)) { errno = EINVAL; return -1; } if (dir_path) { if (!strcmp(name, ".")) { /* "." relative to "foo/bar" is "foo/bar" */ v9fs_path_copy(target, dir_path); } else if (!strcmp(name, "..")) { if (!strcmp(dir_path->data, ".")) { /* ".." relative to the root is "." */ v9fs_path_sprintf(target, "."); } else { char *tmp = g_path_get_dirname(dir_path->data); /* Symbolic links are resolved by the client. We can assume * that ".." relative to "foo/bar" is equivalent to "foo" */ v9fs_path_sprintf(target, "%s", tmp); g_free(tmp); } } else { assert(!strchr(name, '/')); v9fs_path_sprintf(target, "%s/%s", dir_path->data, name); } } else if (!strcmp(name, "/") || !strcmp(name, ".") || !strcmp(name, "..")) { /* This is the root fid */ v9fs_path_sprintf(target, "."); } else { assert(!strchr(name, '/')); v9fs_path_sprintf(target, "./%s", name); } return 0; } static int local_renameat(FsContext *ctx, V9fsPath *olddir, const char *old_name, V9fsPath *newdir, const char *new_name) { int ret; int odirfd, ndirfd; if (ctx->export_flags & V9FS_SM_MAPPED_FILE && (local_is_mapped_file_metadata(ctx, old_name) || local_is_mapped_file_metadata(ctx, new_name))) { errno = EINVAL; return -1; } odirfd = local_opendir_nofollow(ctx, olddir->data); if (odirfd == -1) { return -1; } ndirfd = local_opendir_nofollow(ctx, newdir->data); if (ndirfd == -1) { close_preserve_errno(odirfd); return -1; } ret = qemu_renameat(odirfd, old_name, ndirfd, new_name); if (ret < 0) { goto out; } if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { int omap_dirfd, nmap_dirfd; ret = qemu_mkdirat(ndirfd, VIRTFS_META_DIR, 0700); if (ret < 0 && errno != EEXIST) { goto err_undo_rename; } omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); if (omap_dirfd == -1) { goto err; } nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); if (nmap_dirfd == -1) { close_preserve_errno(omap_dirfd); goto err; } /* rename the .virtfs_metadata files */ ret = qemu_renameat(omap_dirfd, old_name, nmap_dirfd, new_name); close_preserve_errno(nmap_dirfd); close_preserve_errno(omap_dirfd); if (ret < 0 && errno != ENOENT) { goto err_undo_rename; } ret = 0; } goto out; err: ret = -1; err_undo_rename: renameat_preserve_errno(ndirfd, new_name, odirfd, old_name); out: close_preserve_errno(ndirfd); close_preserve_errno(odirfd); return ret; } static void v9fs_path_init_dirname(V9fsPath *path, const char *str) { path->data = g_path_get_dirname(str); path->size = strlen(path->data) + 1; } static int local_rename(FsContext *ctx, const char *oldpath, const char *newpath) { int err; char *oname = g_path_get_basename(oldpath); char *nname = g_path_get_basename(newpath); V9fsPath olddir, newdir; v9fs_path_init_dirname(&olddir, oldpath); v9fs_path_init_dirname(&newdir, newpath); err = local_renameat(ctx, &olddir, oname, &newdir, nname); v9fs_path_free(&newdir); v9fs_path_free(&olddir); g_free(nname); g_free(oname); return err; } static int local_unlinkat(FsContext *ctx, V9fsPath *dir, const char *name, int flags) { int ret; int dirfd; if (ctx->export_flags & V9FS_SM_MAPPED_FILE && local_is_mapped_file_metadata(ctx, name)) { errno = EINVAL; return -1; } dirfd = local_opendir_nofollow(ctx, dir->data); if (dirfd == -1) { return -1; } ret = local_unlinkat_common(ctx, dirfd, name, flags); close_preserve_errno(dirfd); return ret; } #ifdef FS_IOC_GETVERSION static int local_ioc_getversion(FsContext *ctx, V9fsPath *path, mode_t st_mode, uint64_t *st_gen) { 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 = local_open(ctx, path, O_RDONLY, &fid_open); if (err < 0) { return err; } err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen); local_close(ctx, &fid_open); return err; } #endif static int local_ioc_getversion_init(FsContext *ctx, LocalData *data, Error **errp) { #ifdef FS_IOC_GETVERSION struct statfs stbuf; /* * use ioc_getversion only if the ioctl is definied */ if (fstatfs(data->mountfd, &stbuf) < 0) { error_setg_errno(errp, errno, "failed to stat file system at '%s'", ctx->fs_root); return -1; } 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 = local_ioc_getversion; break; } #endif return 0; } static int local_init(FsContext *ctx, Error **errp) { LocalData *data = g_malloc(sizeof(*data)); data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY); if (data->mountfd == -1) { error_setg_errno(errp, errno, "failed to open '%s'", ctx->fs_root); goto err; } if (local_ioc_getversion_init(ctx, data, errp) < 0) { close(data->mountfd); goto err; } if (ctx->export_flags & V9FS_SM_PASSTHROUGH) { ctx->xops = passthrough_xattr_ops; } else if (ctx->export_flags & V9FS_SM_MAPPED) { ctx->xops = mapped_xattr_ops; } else if (ctx->export_flags & V9FS_SM_NONE) { ctx->xops = none_xattr_ops; } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { /* * xattr operation for mapped-file and passthrough * remain same. */ ctx->xops = passthrough_xattr_ops; } ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT; ctx->private = data; return 0; err: g_free(data); return -1; } static void local_cleanup(FsContext *ctx) { LocalData *data = ctx->private; if (!data) { return; } close(data->mountfd); g_free(data); } static void error_append_security_model_hint(Error *const *errp) { error_append_hint(errp, "Valid options are: security_model=" "[passthrough|mapped-xattr|mapped-file|none]\n"); } static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp) { ERRP_GUARD(); const char *sec_model = qemu_opt_get(opts, "security_model"); const char *path = qemu_opt_get(opts, "path"); const char *multidevs = qemu_opt_get(opts, "multidevs"); if (!sec_model) { error_setg(errp, "security_model property not set"); error_append_security_model_hint(errp); return -1; } if (!strcmp(sec_model, "passthrough")) { fse->export_flags |= V9FS_SM_PASSTHROUGH; } else if (!strcmp(sec_model, "mapped") || !strcmp(sec_model, "mapped-xattr")) { fse->export_flags |= V9FS_SM_MAPPED; } else if (!strcmp(sec_model, "none")) { fse->export_flags |= V9FS_SM_NONE; } else if (!strcmp(sec_model, "mapped-file")) { fse->export_flags |= V9FS_SM_MAPPED_FILE; } else { error_setg(errp, "invalid security_model property '%s'", sec_model); error_append_security_model_hint(errp); return -1; } if (multidevs) { if (!strcmp(multidevs, "remap")) { fse->export_flags &= ~V9FS_FORBID_MULTIDEVS; fse->export_flags |= V9FS_REMAP_INODES; } else if (!strcmp(multidevs, "forbid")) { fse->export_flags &= ~V9FS_REMAP_INODES; fse->export_flags |= V9FS_FORBID_MULTIDEVS; } else if (!strcmp(multidevs, "warn")) { fse->export_flags &= ~V9FS_FORBID_MULTIDEVS; fse->export_flags &= ~V9FS_REMAP_INODES; } else { error_setg(errp, "invalid multidevs property '%s'", multidevs); error_append_hint(errp, "Valid options are: multidevs=" "[remap|forbid|warn]\n"); return -1; } } if (!path) { error_setg(errp, "path property not set"); return -1; } if (fsdev_throttle_parse_opts(opts, &fse->fst, errp)) { error_prepend(errp, "invalid throttle configuration: "); return -1; } if (fse->export_flags & V9FS_SM_MAPPED || fse->export_flags & V9FS_SM_MAPPED_FILE) { fse->fmode = qemu_opt_get_number(opts, "fmode", SM_LOCAL_MODE_BITS) & 0777; fse->dmode = qemu_opt_get_number(opts, "dmode", SM_LOCAL_DIR_MODE_BITS) & 0777; } else { if (qemu_opt_find(opts, "fmode")) { error_setg(errp, "fmode is only valid for mapped security modes"); return -1; } if (qemu_opt_find(opts, "dmode")) { error_setg(errp, "dmode is only valid for mapped security modes"); return -1; } } fse->path = g_strdup(path); return 0; } FileOperations local_ops = { .parse_opts = local_parse_opts, .init = local_init, .cleanup = local_cleanup, .lstat = local_lstat, .readlink = local_readlink, .close = local_close, .closedir = local_closedir, .open = local_open, .opendir = local_opendir, .rewinddir = local_rewinddir, .telldir = local_telldir, .readdir = local_readdir, .seekdir = local_seekdir, .preadv = local_preadv, .pwritev = local_pwritev, .chmod = local_chmod, .mknod = local_mknod, .mkdir = local_mkdir, .fstat = local_fstat, .open2 = local_open2, .symlink = local_symlink, .link = local_link, .truncate = local_truncate, .rename = local_rename, .chown = local_chown, .utimensat = local_utimensat, .remove = local_remove, .fsync = local_fsync, .statfs = local_statfs, .lgetxattr = local_lgetxattr, .llistxattr = local_llistxattr, .lsetxattr = local_lsetxattr, .lremovexattr = local_lremovexattr, .name_to_path = local_name_to_path, .renameat = local_renameat, .unlinkat = local_unlinkat, };