Implement sys_readlink and improve sys_mremap

crate/memory/src/memory_set/mod.rs

@@ -301,7 +301,14 @@ impl<T: InactivePageTable> MemorySet<T> {
                     let new_area = MemoryArea { start_addr: area.start_addr, end_addr: start_addr, attr: area.attr, handler: area.handler, name: area.name };
                     self.areas.insert(i, new_area);
                 } else {
-                    unimplemented!("");
+                    // superset
+                    let area = self.areas.remove(i);
+                    let dead_area = MemoryArea { start_addr: start_addr, end_addr: end_addr, attr: area.attr, handler: area.handler.box_clone(), name: area.name };
+                    self.page_table.edit(|pt| dead_area.unmap(pt));
+                    let new_area_left = MemoryArea { start_addr: area.start_addr, end_addr: start_addr, attr: area.attr, handler: area.handler.box_clone(), name: area.name };
+                    self.areas.insert(i, new_area_left);
+                    let new_area_right = MemoryArea { start_addr: end_addr, end_addr: area.start_addr, attr: area.attr, handler: area.handler, name: area.name };
+                    self.areas.insert(i, new_area_right);
                 }
                 return;
             }

kernel/Cargo.lock

@@ -338,12 +338,12 @@ dependencies = [
 [[package]]
 name = "rcore-fs"
 version = "0.1.0"
-source = "git+https://github.com/rcore-os/rcore-fs?branch=sefs#38dab25178eb25abaab8e6d929af354a56158d5f"
+source = "git+https://github.com/rcore-os/rcore-fs?branch=sefs#47df4e1cc97f061fa6eadf66eaacf774d22bb806"
 
 [[package]]
 name = "rcore-fs-sfs"
 version = "0.1.0"
-source = "git+https://github.com/rcore-os/rcore-fs?branch=sefs#38dab25178eb25abaab8e6d929af354a56158d5f"
+source = "git+https://github.com/rcore-os/rcore-fs?branch=sefs#47df4e1cc97f061fa6eadf66eaacf774d22bb806"
 dependencies = [
  "bitvec 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",

kernel/src/syscall/fs.rs

@@ -384,6 +384,23 @@ pub fn sys_lstat(path: *const u8, stat_ptr: *mut Stat) -> SysResult {
     Ok(0)
 }
 
+pub fn sys_readlink(path: *const u8, base: *mut u8, len: usize) -> SysResult {
+    let proc = process();
+    let path = unsafe { proc.vm.check_and_clone_cstr(path)? };
+    proc.vm.check_write_array(base, len)?;
+    info!("readlink: path: {:?}, base: {:?}, len: {}", path, base, len);
+
+    let inode = proc.lookup_inode(&path)?;
+    if inode.metadata()?.type_ == FileType::SymLink {
+        // TODO: recursive link resolution and loop detection
+        let mut slice = unsafe { slice::from_raw_parts_mut(base, len) };
+        let len = inode.read_at(0, &mut slice)?;
+        Ok(len)
+    } else {
+        Err(SysError::EINVAL)
+    }
+}
+
 pub fn sys_lseek(fd: usize, offset: i64, whence: u8) -> SysResult {
     let pos = match whence {
         SEEK_SET => SeekFrom::Start(offset as u64),
@@ -441,7 +458,7 @@ pub fn sys_getdents64(fd: usize, buf: *mut LinuxDirent64, buf_size: usize) -> Sy
             r => r,
         }?;
         // TODO: get ino from dirent
-        let ok = writer.try_write(0, 0, &name);
+        let ok = writer.try_write(0, DirentType::from_type(&info.type_).bits(), &name);
         if !ok { break; }
     }
     Ok(writer.written_size)
@@ -799,6 +816,42 @@ impl DirentBufWriter {
     }
 }
 
+bitflags! {
+    pub struct DirentType: u8 {
+        const DT_UNKNOWN  = 0;
+        /// FIFO (named pipe)
+        const DT_FIFO = 1;
+        /// Character device
+        const DT_CHR  = 2;
+        /// Directory
+        const DT_DIR  = 4;
+        /// Block device
+        const DT_BLK = 6;
+        /// Regular file
+        const DT_REG = 8;
+        /// Symbolic link
+        const DT_LNK = 10;
+        /// UNIX domain socket
+        const DT_SOCK  = 12;
+        /// ???
+        const DT_WHT = 14;
+    }
+}
+
+impl DirentType {
+    fn from_type(type_: &FileType) -> Self {
+        match type_ {
+            FileType::File => Self::DT_REG,
+            FileType::Dir => Self::DT_DIR,
+            FileType::SymLink => Self::DT_LNK,
+            FileType::CharDevice => Self::DT_CHR,
+            FileType::BlockDevice => Self::DT_BLK,
+            FileType::Socket => Self::DT_SOCK,
+            FileType::NamedPipe => Self::DT_FIFO,
+        }
+    }
+}
+
 #[cfg(target_arch = "x86_64")]
 #[repr(C)]
 #[derive(Debug)]

kernel/src/syscall/mod.rs

@@ -243,16 +243,13 @@ fn x86_64_syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> Option<Sys
         SYS_RMDIR => sys_rmdir(args[0] as *const u8),
         SYS_LINK => sys_link(args[0] as *const u8, args[1] as *const u8),
         SYS_UNLINK => sys_unlink(args[0] as *const u8),
+        SYS_READLINK => sys_readlink(args[0] as *const u8, args[1] as *mut u8, args[2]),
         SYS_ARCH_PRCTL => sys_arch_prctl(args[0] as i32, args[1], tf),
         SYS_TIME => sys_time(args[0] as *mut u64),
         SYS_ALARM => {
             warn!("sys_alarm is unimplemented");
             Ok(0)
         }
-        SYS_READLINK => {
-            warn!("sys_readlink is unimplemented");
-            Err(SysError::ENOENT)
-        }
         SYS_CHOWN => {
             warn!("sys_chown is unimplemented");
             Ok(0)