diff options
author | 2023-10-10 11:40:56 +0000 | |
---|---|---|
committer | 2023-10-10 11:40:56 +0000 | |
commit | e02cda008591317b1625707ff8e115a4841aa889 (patch) | |
tree | aee302e3cf8b59ec2d32ec481be3d1afddfc8968 /hw/9pfs/9p-local.c | |
parent | cc668e6b7e0ffd8c9d130513d12053cf5eda1d3b (diff) |
Introduce Virtio-loopback epsilon release:
Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.
Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9
Diffstat (limited to 'hw/9pfs/9p-local.c')
-rw-r--r-- | hw/9pfs/9p-local.c | 1601 |
1 files changed, 1601 insertions, 0 deletions
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c new file mode 100644 index 000000000..210d9e770 --- /dev/null +++ b/hw/9pfs/9p-local.c @@ -0,0 +1,1601 @@ +/* + * 9p Posix callback + * + * Copyright IBM, Corp. 2010 + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * + * 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 <arpa/inet.h> +#include <pwd.h> +#include <grp.h> +#include <sys/socket.h> +#include <sys/un.h> +#include "qemu/xattr.h" +#include "qapi/error.h" +#include "qemu/cutils.h" +#include "qemu/error-report.h" +#include "qemu/option.h" +#include <libgen.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 { + 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; + renameat(odirfd, opath, ndirfd, npath); + errno = serrno; +} + +static void unlinkat_preserve_errno(int dirfd, const char *path, int flags) +{ + int serrno = errno; + 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 = 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 = 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 (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; + } + + 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 = 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 = 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 = 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 = 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 (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) { + stbuf->st_uid = le32_to_cpu(tmp_uid); + } + if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) { + stbuf->st_gid = le32_to_cpu(tmp_gid); + } + if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) { + stbuf->st_mode = le32_to_cpu(tmp_mode); + } + if (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 = 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 = 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 = 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 = unlinkat(map_dirfd, name, 0); + close_preserve_errno(map_dirfd); + if (ret < 0 && errno != ENOENT) { + return -1; + } + } else if (errno != ENOENT) { + return -1; + } + } + + return 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 (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 = 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 = 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 = 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, +}; 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