sh: Do not leak memory when using cd

apps/cat.cpp

@@ -14,11 +14,12 @@ static Result<void> do_cat(StringView path)
     else
         f = TRY(File::open(path, File::ReadOnly));
 
+    auto buf = TRY(Buffer::create_sized(4096));
     while (1)
     {
-        String line = TRY(f->read_line());
-        if (line.is_empty()) break;
-        out->write(line.view());
+        TRY(f->read(buf, 4096));
+        if (buf.is_empty()) break;
+        out->write(buf);
     }
 
     return {};

apps/sh.cpp

@@ -14,7 +14,7 @@
 
 using os::File;
 
-static Result<Vector<char*>> split_command_into_argv(StringView cmd)
+static Result<Vector<char*>> split_command_into_argv(StringView cmd, char** out)
 {
     char* str = strdup(cmd.chars());
 
@@ -33,13 +33,15 @@ static Result<Vector<char*>> split_command_into_argv(StringView cmd)
         if (segment == NULL) return result;
     }
 
+    if (out) *out = str;
+
     return result;
 }
 
 [[noreturn]] static void execute_command(StringView command)
 {
     Vector<char*> argv;
-    bool ok = split_command_into_argv(command).try_move_value_or_error(argv, errno);
+    bool ok = split_command_into_argv(command, nullptr).try_move_value_or_error(argv, errno);
     if (!ok)
     {
         perror("failed to parse command");
@@ -73,7 +75,10 @@ Result<int> luna_main(int argc, char** argv)
         interactive = true;
     }
     else
+    {
         input_file = TRY(File::open(path, File::ReadOnly));
+        input_file->set_close_on_exec();
+    }
 
     while (1)
     {
@@ -90,17 +95,21 @@ Result<int> luna_main(int argc, char** argv)
 
         if (!strncmp(cmd.chars(), "cd", 2))
         {
-            auto args = TRY(split_command_into_argv(cmd.view()));
+            char* copy = nullptr;
+
+            auto args = TRY(split_command_into_argv(cmd.view(), &copy));
             check("cd"_sv == args[0]);
 
             if (args.size() == 2)
             {
                 auto home = TRY(os::FileSystem::home_directory());
                 if (chdir(home.chars()) < 0) perror("cd");
+                free(copy);
                 continue;
             }
 
             if (chdir(args[1]) < 0) perror("cd");
+            free(copy);
             continue;
         }
 

libluna/include/luna/Buffer.h

@@ -46,6 +46,11 @@ class Buffer
         return m_size;
     }
 
+    bool is_empty() const
+    {
+        return m_size == 0;
+    }
+
   private:
     Buffer(u8* data, usize size);
 

libos/include/os/File.h

@@ -31,9 +31,12 @@ namespace os
         void set_close_on_exec();
 
         Result<void> write(StringView str);
+        Result<void> write(const Buffer& buf);
 
         Result<String> read_line();
 
+        Result<void> read(Buffer& buf, usize size);
+
         Result<int> getchar();
 
         File(Badge<File>);

libos/src/File.cpp

@@ -101,6 +101,13 @@ namespace os
         return {};
     }
 
+    Result<void> File::write(const Buffer& buf)
+    {
+        TRY(raw_write(buf.data(), buf.size()));
+
+        return {};
+    }
+
     Result<String> File::read_line()
     {
         Vector<char> data;
@@ -124,6 +131,17 @@ namespace os
         return String::from_cstring(data.data());
     }
 
+    Result<void> File::read(Buffer& buf, usize size)
+    {
+        u8* slice = TRY(buf.slice(0, size));
+
+        usize nread = TRY(raw_read(slice, size));
+
+        TRY(buf.try_resize(nread));
+
+        return {};
+    }
+
     Result<int> File::getchar()
     {
         char value;