options/posix: Implement posix_fallocate()

options/internal/include/mlibc/sysdeps.hpp

@@ -28,6 +28,7 @@ int sys_isatty(int fd, int *ptr);
 int sys_stat(const char *pathname, struct stat *statbuf);
 int sys_fstat(int fd, struct stat *statbuf);
 int sys_readlink(const char *path, void *buffer, size_t max_size, ssize_t *length);
+int sys_fallocate(int fd, off_t offset, size_t size);
 int sys_unlink(const char *path);
 int sys_socket(int family, int type, int protocol, int *fd);
 gid_t sys_getgid();

options/posix/generic/fcntl-stubs.cpp

@@ -1,9 +1,8 @@
 
-#include <cstdarg>
-
-#include <fcntl.h>
-
+#include <errno.h>
 #include <bits/ensure.h>
+#include <fcntl.h>
+#include <stdarg.h>
 
 #include <mlibc/sysdeps.hpp>
 
@@ -28,9 +27,24 @@ int posix_fadvise(int, off_t, off_t, int) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
 }
-int posix_fallocate(int, off_t, off_t) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+int posix_fallocate(int fd, off_t offset, off_t size) {
+	struct error_guard {
+		error_guard()
+		: _s{errno} { }
+
+		~error_guard() {
+			errno = _s;
+		}
+
+	private:
+		int _s;
+	};
+
+	error_guard guard;
+
+	if(mlibc::sys_fallocate(fd, offset, size))
+		return errno;
+	return 0;
 }
 
 // This is a linux extension

sysdeps/managarm/generic/file.cpp

@@ -1938,6 +1938,46 @@ int sys_readlink(const char *path, void *data, size_t max_size, ssize_t *length)
 	}
 }
 
+int sys_fallocate(int fd, off_t offset, size_t size) {
+	HelAction actions[3];
+	globalQueue.trim();
+
+	auto handle = cacheFileTable()[fd];
+	__ensure(handle);
+	
+	managarm::fs::CntRequest<MemoryAllocator> req(getAllocator());
+	req.set_req_type(managarm::fs::CntReqType::PT_FALLOCATE);
+	req.set_rel_offset(offset);
+	req.set_size(size);
+
+	frigg::String<MemoryAllocator> ser(getAllocator());
+	req.SerializeToString(&ser);
+	actions[0].type = kHelActionOffer;
+	actions[0].flags = kHelItemAncillary;
+	actions[1].type = kHelActionSendFromBuffer;
+	actions[1].flags = kHelItemChain;
+	actions[1].buffer = ser.data();
+	actions[1].length = ser.size();
+	actions[2].type = kHelActionRecvInline;
+	actions[2].flags = 0;
+	HEL_CHECK(helSubmitAsync(handle, actions, 3,
+			globalQueue.getQueue(), 0, 0));
+
+	auto element = globalQueue.dequeueSingle();
+	auto offer = parseSimple(element);
+	auto send_req = parseSimple(element);
+	auto recv_resp = parseInline(element);
+
+	HEL_CHECK(offer->error);
+	HEL_CHECK(send_req->error);
+	HEL_CHECK(recv_resp->error);
+
+	managarm::fs::SvrResponse<MemoryAllocator> resp(getAllocator());
+	resp.ParseFromArray(recv_resp->data, recv_resp->length);
+	__ensure(resp.error() == managarm::fs::Errors::SUCCESS);
+	return 0;
+}
+
 int sys_unlink(const char *path) {
 	HelAction actions[3];