feat(isolation/filemap): Use proper tree for all file lookups [WIP]

Author: fogti

src/hypercall.rs

@@ -14,7 +14,7 @@ use uhyve_interface::{
 use crate::{
 	isolation::{
 		fd::{FdData, GuestFd, UhyveFileDescriptorLayer},
-		filemap::UhyveFileMap,
+		filemap::{UhyveFileMap, UhyveTreeFile},
 	},
 	mem::MmapMemory,
 	params::EnvVars,
@@ -129,18 +129,27 @@ fn translate_last_errno() -> Option<i32> {
 pub fn unlink(mem: &MmapMemory, sysunlink: &mut UnlinkParams, file_map: &mut UhyveFileMap) {
 	let requested_path_ptr = mem.host_address(sysunlink.name).unwrap() as *const i8;
 	let guest_path = unsafe { CStr::from_ptr(requested_path_ptr) };
-	sysunlink.ret = if let Some(host_path) = file_map.get_host_path(guest_path) {
-		// We can safely unwrap here, as host_path.as_bytes will never contain internal \0 bytes
-		// As host_path_c_string is a valid CString, this implementation is presumed to be safe.
-		let host_path_c_string = CString::new(host_path.as_bytes()).unwrap();
-		if unsafe { libc::unlink(host_path_c_string.as_c_str().as_ptr()) } < 0 {
-			-translate_last_errno().unwrap_or(1)
-		} else {
+	sysunlink.ret = match file_map.unlink(guest_path) {
+		Ok(Some(host_path)) => {
+			// We can safely unwrap here, as host_path.as_bytes will never contain internal \0 bytes
+			// As host_path_c_string is a valid CString, this implementation is presumed to be safe.
+			let host_path_c_string = CString::new(host_path.as_bytes()).unwrap();
+			if unsafe { libc::unlink(host_path_c_string.as_c_str().as_ptr()) } < 0 {
+				-translate_last_errno().unwrap_or(1)
+			} else {
+				0
+			}
+		}
+		Ok(None) => {
+			// Removed virtual entry
 			0
 		}
-	} else {
-		error!("The kernel requested to unlink() an unknown path ({guest_path:?}): Rejecting...");
-		-ENOENT
+		Err(()) => {
+			error!(
+				"The kernel requested to unlink() an unknown path ({guest_path:?}): Rejecting..."
+			);
+			-ENOENT
+		}
 	};
 }
 
@@ -181,10 +190,25 @@ pub fn open(mem: &MmapMemory, sysopen: &mut OpenParams, file_map: &mut UhyveFile
 
 	sysopen.ret = if let Some(host_path) = file_map.get_host_path(guest_path) {
 		debug!("{guest_path:#?} found in file map.");
-		// We can safely unwrap here, as host_path.as_bytes will never contain internal \0 bytes
-		// As host_path_c_string is a valid CString, this implementation is presumed to be safe.
-		let host_path_c_string = CString::new(host_path.as_bytes()).unwrap();
-		do_open(&mut file_map.fdmap, host_path_c_string, flags, sysopen.mode)
+		match host_path {
+			UhyveTreeFile::OnHost(host_path) => {
+				// We can safely unwrap here, as host_path.as_bytes will never contain internal \0 bytes
+				// As host_path_c_string is a valid CString, this implementation is presumed to be safe.
+				let host_path_c_string = CString::new(host_path.as_os_str().as_bytes()).unwrap();
+				do_open(&mut file_map.fdmap, host_path_c_string, flags, sysopen.mode)
+			}
+			UhyveTreeFile::Virtual(data) => {
+				if let Some(guest_fd) = file_map.fdmap.insert(FdData::Virtual {
+					// The following only clones a pointer, and increases an `Arc` refcount.
+					data: data.clone(),
+					offset: 0,
+				}) {
+					guest_fd.0
+				} else {
+					-ENOENT
+				}
+			}
+		}
 	} else {
 		debug!("{guest_path:#?} not found in file map.");
 		if (flags & O_CREAT) == O_CREAT {
@@ -198,8 +222,15 @@ pub fn open(mem: &MmapMemory, sysopen: &mut OpenParams, file_map: &mut UhyveFile
 				flags |= file_map.get_io_mode_flags();
 			}
 
-			let host_path_c_string = file_map.create_temporary_file(guest_path);
-			do_open(&mut file_map.fdmap, host_path_c_string, flags, sysopen.mode)
+			match file_map.create_temporary_file(guest_path) {
+				Some(host_path_c_string) => {
+					do_open(&mut file_map.fdmap, host_path_c_string, flags, sysopen.mode)
+				}
+				None => {
+					debug!("Returning -EINVAL for {guest_path:#?}");
+					-EINVAL
+				}
+			}
 		} else {
 			debug!("Returning -ENOENT for {guest_path:#?}");
 			-ENOENT