Create close system call

kernel/include/scheduler.hpp

@@ -38,6 +38,7 @@ void sleep_ms(pid_t pid, size_t time);
 
 size_t register_new_handle(const std::string& path);
 bool has_handle(size_t fd);
+void release_handle(size_t fd);
 const std::string& get_handle(size_t fd);
 
 } //end of namespace scheduler

kernel/include/vfs.hpp

@@ -15,6 +15,7 @@
 namespace vfs {
 
 int64_t open(const char* file);
+void close(size_t fd);
 int64_t stat(size_t fd, stat_info& info);
 
 } //end of namespace vfs

kernel/src/scheduler.cpp

@@ -814,6 +814,10 @@ size_t scheduler::register_new_handle(const std::string& path){
     return pcb[current_pid].handles.size() - 1;
 }
 
+void scheduler::release_handle(size_t fd){
+    pcb[current_pid].handles[fd] = nullptr;
+}
+
 bool scheduler::has_handle(size_t fd){
     return pcb[current_pid].handles.size() - 1 <= fd;
 }

kernel/src/system_calls.cpp

@@ -109,6 +109,12 @@ void sc_open(interrupt::syscall_regs* regs){
     regs->rax = vfs::open(file);
 }
 
+void sc_close(interrupt::syscall_regs* regs){
+    auto fd = regs->rbx;
+
+    vfs::close(fd);
+}
+
 void sc_stat(interrupt::syscall_regs* regs){
     auto fd = regs->rbx;
     auto info = reinterpret_cast<stat_info*>(regs->rcx);
@@ -186,6 +192,10 @@ void system_call_entry(interrupt::syscall_regs* regs){
             sc_stat(regs);
             break;
 
+        case 302:
+            sc_close(regs);
+            break;
+
         case 0x666:
             //TODO Do something with return code
             scheduler::kill_current_process();

kernel/src/vfs.cpp

@@ -55,6 +55,12 @@ int64_t vfs::open(const char* file_path){
     return -std::ERROR_NOT_EXISTS;
 }
 
+void vfs::close(size_t fd){
+    if(scheduler::has_handle(fd)){
+        scheduler::release_handle(fd);
+    }
+}
+
 int64_t vfs::stat(size_t fd, stat_info& info){
     if(!disks::mounted_partition() || !disks::mounted_disk()){
         return -std::ERROR_NOTHING_MOUNTED;

programs/stat/src/main.cpp

@@ -87,6 +87,8 @@ int main(int argc, char* argv[]){
         } else {
             printf("stat: error: %s\n", std::error_message(info.error()));
         }
+
+        close(*fd);
     } else {
         printf("stat: error: %s\n", std::error_message(fd.error()));
     }

tlib/include/file.hpp

@@ -14,6 +14,7 @@
 #include <stat_info.hpp>
 
 std::expected<size_t> open(const char* file);
+void close(size_t fd);
 std::expected<stat_info> stat(size_t fd);
 
 #endif

tlib/src/file.cpp

@@ -20,6 +20,12 @@ std::expected<size_t> open(const char* file){
         return std::make_expected<size_t>(fd);
     }
 }
+void close(size_t fd){
+    asm volatile("mov rax, 302; mov rbx, %[fd]; int 50;"
+        : /* No outputs */
+        : [fd] "g" (fd)
+        : "rax", "rbx");
+}
 
 std::expected<stat_info> stat(size_t fd){
     stat_info info;