Add user program initproc/user_shell, allow user programs allocate data on heap.

user/src/lib.rs

@@ -2,17 +2,36 @@
 #![feature(llvm_asm)]
 #![feature(linkage)]
 #![feature(panic_info_message)]
+#![feature(alloc_error_handler)]
 
 #[macro_use]
 pub mod console;
 mod syscall;
 mod lang_items;
 
+use syscall::*;
+use buddy_system_allocator::LockedHeap;
+
+const USER_HEAP_SIZE: usize = 16384;
+
+static mut HEAP_SPACE: [u8; USER_HEAP_SIZE] = [0; USER_HEAP_SIZE];
+
+#[global_allocator]
+static HEAP: LockedHeap = LockedHeap::empty();
+
+#[alloc_error_handler]
+pub fn handle_alloc_error(layout: core::alloc::Layout) -> ! {
+    panic!("Heap allocation error, layout = {:?}", layout);
+}
+
 #[no_mangle]
 #[link_section = ".text.entry"]
 pub extern "C" fn _start() -> ! {
-    syscall::sys_exit(main());
-    panic!("unreachable after sys_exit!");
+    unsafe {
+        HEAP.lock()
+            .init(HEAP_SPACE.as_ptr() as usize, USER_HEAP_SIZE);
+    }
+    exit(main());
 }
 
 #[linkage = "weak"]
@@ -21,5 +40,15 @@ fn main() -> i32 {
     panic!("Cannot find main!");
 }
 
-
-pub use syscall::*;
+pub fn read(fd: usize, buf: &mut [u8]) -> isize { sys_read(fd, buf) }
+pub fn write(fd: usize, buf: &[u8]) -> isize { sys_write(fd, buf) }
+pub fn exit(xstate: i32) -> ! { sys_exit(xstate); }
+pub fn yield_() -> isize { sys_yield() }
+pub fn get_time() -> isize { sys_get_time() }
+pub fn getpid() -> isize { sys_getpid() }
+pub fn fork() -> isize { sys_fork() }
+pub fn exec(path: &str) -> isize { sys_exec(path) }
+pub fn wait(xstate: &mut i32) -> isize { sys_waitpid(-1, xstate as *mut _) }
+pub fn waitpid(pid: usize, xstate: &mut i32) -> isize {
+    sys_waitpid(pid as isize, xstate as *mut _)
+}