Strictly speaking, this is not necessary, because lo_inode_open() will always return a new FD owned by the caller, so TempFd.owned will always be true.
However, auto-cleanup is nice, and in some cases this plays nicely with an lo_inode_fd() call in another conditional branch (see lo_setattr()). Signed-off-by: Max Reitz <mre...@redhat.com> --- tools/virtiofsd/passthrough_ll.c | 138 +++++++++++++------------------ 1 file changed, 59 insertions(+), 79 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 9e1bc37af8..292b7f7e27 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -291,10 +291,8 @@ static void temp_fd_clear(TempFd *temp_fd) /** * Return an owned fd from *temp_fd that will not be closed when * *temp_fd goes out of scope. - * - * (TODO: Remove __attribute__ once this is used.) */ -static __attribute__((unused)) int temp_fd_steal(TempFd *temp_fd) +static int temp_fd_steal(TempFd *temp_fd) { if (temp_fd->owned) { temp_fd->owned = false; @@ -673,9 +671,12 @@ static int lo_fd(fuse_req_t req, fuse_ino_t ino, TempFd *tfd) * when a malicious client opens special files such as block device nodes. * Symlink inodes are also rejected since symlinks must already have been * traversed on the client side. + * + * The fd is returned in tfd->fd. The return value is 0 on success and -errno + * otherwise. */ -static int lo_inode_open(struct lo_data *lo, struct lo_inode *inode, - int open_flags) +static int lo_inode_open(const struct lo_data *lo, const struct lo_inode *inode, + int open_flags, TempFd *tfd) { g_autofree char *fd_str = g_strdup_printf("%d", inode->fd); int fd; @@ -694,7 +695,13 @@ static int lo_inode_open(struct lo_data *lo, struct lo_inode *inode, if (fd < 0) { return -errno; } - return fd; + + *tfd = (TempFd) { + .fd = fd, + .owned = true, + }; + + return 0; } static void lo_init(void *userdata, struct fuse_conn_info *conn) @@ -852,7 +859,12 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, return; } - res = lo_inode_fd(inode, &inode_fd); + if (!fi && (valid & FUSE_SET_ATTR_SIZE)) { + /* We need an O_RDWR FD for ftruncate() */ + res = lo_inode_open(lo, inode, O_RDWR, &inode_fd); + } else { + res = lo_inode_fd(inode, &inode_fd); + } if (res < 0) { saverr = -res; goto out_err; @@ -900,18 +912,11 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, if (fi) { truncfd = fd; } else { - truncfd = lo_inode_open(lo, inode, O_RDWR); - if (truncfd < 0) { - saverr = -truncfd; - goto out_err; - } + truncfd = inode_fd.fd; } saverr = drop_security_capability(lo, truncfd); if (saverr) { - if (!fi) { - close(truncfd); - } goto out_err; } @@ -919,9 +924,6 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, res = drop_effective_cap("FSETID", &cap_fsetid_dropped); if (res != 0) { saverr = res; - if (!fi) { - close(truncfd); - } goto out_err; } } @@ -934,9 +936,6 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, fuse_log(FUSE_LOG_ERR, "Failed to gain CAP_FSETID\n"); } } - if (!fi) { - close(truncfd); - } if (res == -1) { goto out_err; } @@ -1822,11 +1821,12 @@ static struct lo_dirp *lo_dirp(fuse_req_t req, struct fuse_file_info *fi) static void lo_opendir(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) { + g_auto(TempFd) inode_fd = TEMP_FD_INIT; int error = ENOMEM; struct lo_data *lo = lo_data(req); struct lo_inode *inode; struct lo_dirp *d = NULL; - int fd; + int res; ssize_t fh; inode = lo_inode(req, ino); @@ -1840,13 +1840,13 @@ static void lo_opendir(fuse_req_t req, fuse_ino_t ino, goto out_err; } - fd = lo_inode_open(lo, inode, O_RDONLY); - if (fd < 0) { - error = -fd; + res = lo_inode_open(lo, inode, O_RDONLY, &inode_fd); + if (res < 0) { + error = -res; goto out_err; } - d->dp = fdopendir(fd); + d->dp = fdopendir(temp_fd_steal(&inode_fd)); if (d->dp == NULL) { goto out_errno; } @@ -1876,8 +1876,6 @@ out_err: if (d) { if (d->dp) { closedir(d->dp); - } else if (fd != -1) { - close(fd); } free(d); } @@ -2077,6 +2075,7 @@ static void update_open_flags(int writeback, int allow_direct_io, static int lo_do_open(struct lo_data *lo, struct lo_inode *inode, int existing_fd, struct fuse_file_info *fi) { + g_auto(TempFd) inode_fd = TEMP_FD_INIT; ssize_t fh; int fd = existing_fd; int err; @@ -2093,16 +2092,18 @@ static int lo_do_open(struct lo_data *lo, struct lo_inode *inode, } } - fd = lo_inode_open(lo, inode, fi->flags); + err = lo_inode_open(lo, inode, fi->flags, &inode_fd); if (cap_fsetid_dropped) { if (gain_effective_cap("FSETID")) { fuse_log(FUSE_LOG_ERR, "Failed to gain CAP_FSETID\n"); } } - if (fd < 0) { - return -fd; + if (err < 0) { + return -err; } + fd = temp_fd_steal(&inode_fd); + if (fi->flags & (O_TRUNC)) { int err = drop_security_capability(lo, fd); if (err) { @@ -2212,8 +2213,9 @@ static struct lo_inode_plock *lookup_create_plock_ctx(struct lo_data *lo, uint64_t lock_owner, pid_t pid, int *err) { + g_auto(TempFd) inode_fd = TEMP_FD_INIT; struct lo_inode_plock *plock; - int fd; + int res; plock = g_hash_table_lookup(inode->posix_locks, GUINT_TO_POINTER(lock_owner)); @@ -2230,15 +2232,15 @@ static struct lo_inode_plock *lookup_create_plock_ctx(struct lo_data *lo, /* Open another instance of file which can be used for ofd locks. */ /* TODO: What if file is not writable? */ - fd = lo_inode_open(lo, inode, O_RDWR); - if (fd < 0) { - *err = -fd; + res = lo_inode_open(lo, inode, O_RDWR, &inode_fd); + if (res < 0) { + *err = -res; free(plock); return NULL; } plock->lock_owner = lock_owner; - plock->fd = fd; + plock->fd = temp_fd_steal(&inode_fd); g_hash_table_insert(inode->posix_locks, GUINT_TO_POINTER(plock->lock_owner), plock); return plock; @@ -2454,6 +2456,7 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) { + g_auto(TempFd) inode_fd = TEMP_FD_INIT; struct lo_inode *inode = lo_inode(req, ino); struct lo_data *lo = lo_data(req); int res; @@ -2468,11 +2471,12 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, } if (!fi) { - fd = lo_inode_open(lo, inode, O_RDWR); - if (fd < 0) { - res = -fd; + res = lo_inode_open(lo, inode, O_RDWR, &inode_fd); + if (res < 0) { + res = -res; goto out; } + fd = inode_fd.fd; } else { fd = lo_fi_fd(req, fi); } @@ -2482,9 +2486,6 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, } else { res = fsync(fd) == -1 ? errno : 0; } - if (!fi) { - close(fd); - } out: lo_inode_put(lo, &inode); fuse_reply_err(req, res); @@ -3047,7 +3048,6 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, struct lo_inode *inode; ssize_t ret; int saverr; - int fd = -1; if (block_xattr(lo, in_name)) { fuse_reply_err(req, EOPNOTSUPP); @@ -3099,12 +3099,12 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, * Otherwise, call fchdir() to avoid open(). */ if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) { - fd = lo_inode_open(lo, inode, O_RDONLY); - if (fd < 0) { - saverr = -fd; + ret = lo_inode_open(lo, inode, O_RDONLY, &inode_fd); + if (ret < 0) { + saverr = -ret; goto out; } - ret = fgetxattr(fd, name, value, size); + ret = fgetxattr(inode_fd.fd, name, value, size); saverr = ret == -1 ? errno : 0; } else { ret = lo_inode_fd(inode, &inode_fd); @@ -3133,10 +3133,6 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, fuse_reply_xattr(req, ret); } out_free: - if (fd >= 0) { - close(fd); - } - lo_inode_put(lo, &inode); return; @@ -3157,7 +3153,6 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) struct lo_inode *inode; ssize_t ret; int saverr; - int fd = -1; inode = lo_inode(req, ino); if (!inode) { @@ -3181,12 +3176,12 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) } if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) { - fd = lo_inode_open(lo, inode, O_RDONLY); - if (fd < 0) { - saverr = -fd; + ret = lo_inode_open(lo, inode, O_RDONLY, &inode_fd); + if (ret < 0) { + saverr = -ret; goto out; } - ret = flistxattr(fd, value, size); + ret = flistxattr(inode_fd.fd, value, size); saverr = ret == -1 ? errno : 0; } else { ret = lo_inode_fd(inode, &inode_fd); @@ -3273,10 +3268,6 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) fuse_reply_xattr(req, ret); } out_free: - if (fd >= 0) { - close(fd); - } - lo_inode_put(lo, &inode); return; @@ -3299,7 +3290,6 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, struct lo_inode *inode; ssize_t ret; int saverr; - int fd = -1; bool switched_creds = false; bool cap_fsetid_dropped = false; struct lo_cred old = {}; @@ -3345,9 +3335,9 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, */ open_inode = S_ISREG(inode->filetype) || S_ISDIR(inode->filetype); if (open_inode) { - fd = lo_inode_open(lo, inode, O_RDONLY); - if (fd < 0) { - saverr = -fd; + ret = lo_inode_open(lo, inode, O_RDONLY, &inode_fd); + if (ret < 0) { + saverr = -ret; goto out; } } else { @@ -3382,8 +3372,7 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, switched_creds = true; } if (open_inode) { - assert(fd >= 0); - ret = fsetxattr(fd, name, value, size, flags); + ret = fsetxattr(inode_fd.fd, name, value, size, flags); saverr = ret == -1 ? errno : 0; } else { ret = setxattr(procname, name, value, size, flags); @@ -3402,10 +3391,6 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, } out: - if (fd >= 0) { - close(fd); - } - lo_inode_put(lo, &inode); g_free(mapped_name); fuse_reply_err(req, saverr); @@ -3421,7 +3406,6 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name) struct lo_inode *inode; ssize_t ret; int saverr; - int fd = -1; if (block_xattr(lo, in_name)) { fuse_reply_err(req, EOPNOTSUPP); @@ -3457,12 +3441,12 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name) name); if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) { - fd = lo_inode_open(lo, inode, O_RDONLY); - if (fd < 0) { - saverr = -fd; + ret = lo_inode_open(lo, inode, O_RDONLY, &inode_fd); + if (ret < 0) { + saverr = -ret; goto out; } - ret = fremovexattr(fd, name); + ret = fremovexattr(inode_fd.fd, name); saverr = ret == -1 ? errno : 0; } else { ret = lo_inode_fd(inode, &inode_fd); @@ -3479,10 +3463,6 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name) } out: - if (fd >= 0) { - close(fd); - } - lo_inode_put(lo, &inode); g_free(mapped_name); fuse_reply_err(req, saverr); -- 2.31.1