From: Fotis Xenakis <[email protected]> Committer: Waldemar Kozaczuk <[email protected]> Branch: master
virtio-fs: implement readdir Signed-off-by: Fotis Xenakis <[email protected]> Message-Id: <am0pr03mb6292510f3fc9656870453a98a6...@am0pr03mb6292.eurprd03.prod.outlook.com> --- diff --git a/fs/virtiofs/virtiofs_vnops.cc b/fs/virtiofs/virtiofs_vnops.cc --- a/fs/virtiofs/virtiofs_vnops.cc +++ b/fs/virtiofs/virtiofs_vnops.cc @@ -13,6 +13,7 @@ #include <sys/param.h> #include <sys/stat.h> #include <sys/types.h> +#include <tuple> #include <osv/contiguous_alloc.hh> #include <osv/debug.h> @@ -24,6 +25,7 @@ #include <osv/sched.hh> #include <osv/vnode.h> +#include "fuse_kernel.h" #include "virtiofs.hh" #include "virtiofs_dax.hh" #include "virtiofs_i.hh" @@ -264,11 +266,81 @@ static int virtiofs_read(struct vnode* vnode, struct file* fp, struct uio* uio, ioflag, *drv, *uio); } +// Checks if @buf (with size @len) points to a valid fuse_dirent (with its name +// not exceeding @name_max) and if so returns @buf. Otherwise, returns nullptr. +static fuse_dirent* parse_fuse_dirent(void* buf, size_t len, size_t name_max) +{ + if (len < FUSE_NAME_OFFSET) { + return nullptr; + } + + auto* fdir = static_cast<struct fuse_dirent*>(buf); + if (FUSE_DIRENT_SIZE(fdir) > len || fdir->namelen > name_max) { + return nullptr; + } + + return fdir; +} + static int virtiofs_readdir(struct vnode* vnode, struct file* fp, struct dirent* dir) { - // TODO: Implement - return EPERM; + auto* inode = static_cast<virtiofs_inode*>(vnode->v_data); + auto* file_data = static_cast<virtiofs_file_data*>(fp->f_data); + auto* m_data = static_cast<virtiofs_mount_data*>(vnode->v_mount->m_data); + auto* drv = m_data->drv; + + // NOTE: The response consists of a buffer of size <= fuse_read_in.size. + // This contains multiple (whole) fuse_dirent structs, each padded to 64-bit + // boundary. We only parse one such struct at a time, for simplicity. The + // fuse_dirent.name field is _not_ null-terminated, but our dirent.d_name + // is, requiring caution. + std::unique_ptr<fuse_read_in> in_args {new (std::nothrow) fuse_read_in()}; + constexpr size_t name_max = sizeof(dir->d_name) - 1; // account for '\0' + // The size of a (padded) fuse_dirent with a name_max-long name + size_t bufsize = FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + name_max); + std::unique_ptr<void, std::function<void(void*)>> buf { + memory::alloc_phys_contiguous_aligned(bufsize, + alignof(std::max_align_t)), memory::free_phys_contiguous_aligned }; + if (!in_args || !buf) { + return ENOMEM; + } + in_args->fh = file_data->file_handle; + in_args->offset = fp->f_offset; + in_args->size = bufsize; + in_args->flags = fp->f_flags; + + size_t len; + int error; + std::tie(len, error) = fuse_req_send_and_receive_reply(drv, FUSE_READDIR, + inode->nodeid, in_args.get(), sizeof(*in_args), buf.get(), bufsize); + if (error) { + kprintf("[virtiofs] inode %lld, readdir failed\n", inode->nodeid); + return error; + } + + if (len == 0) { + return ENOENT; + } + auto* fdir = parse_fuse_dirent(buf.get(), len, name_max); + if (!fdir) { + kprintf("[virtiofs] inode %lld, dirent parsing failed\n", + inode->nodeid); + return EIO; + } + + dir->d_ino = fdir->ino; + dir->d_off = fdir->off; + dir->d_type = fdir->type; + // Copy fdir->name (not null-terminated) to dir->d_name (null-terminated) + memcpy(dir->d_name, fdir->name, fdir->namelen); + dir->d_name[fdir->namelen] = '\0'; + + fp->f_offset = fdir->off; + + virtiofs_debug("inode %lld, read dir entry %s\n", inode->nodeid, + dir->d_name); + return 0; } static int virtiofs_getattr(struct vnode* vnode, struct vattr* attr) -- You received this message because you are subscribed to the Google Groups "OSv Development" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/osv-dev/000000000000cc088805aafd166b%40google.com.
