Signed-off-by: Fotis Xenakis <[email protected]>
---
fs/virtiofs/virtiofs_vnops.cc | 76 ++++++++++++++++++++++++++++++++++-
1 file changed, 74 insertions(+), 2 deletions(-)
diff --git a/fs/virtiofs/virtiofs_vnops.cc b/fs/virtiofs/virtiofs_vnops.cc
index 4bea964e..66eb6fb3 100644
--- 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)
--
2.27.0
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