1 files changed, 35 insertions, 0 deletions
diff --git a/src/harness_adapter.c b/src/harness_adapter.c
index 5a9b9a4..6ae8c66 100644
--- a/src/harness_adapter.c
+++ b/src/harness_adapter.c
@@ -5,8 +5,43 @@
 
 #include "HsFFI.h"
 #include "plugin_interface.h"
+#include <stdio.h>
 
 const char *plugin_name = "Wetterhorn";
 
 void plugin_load(int argc, char **argv) { hs_init(&argc, &argv); }
 void plugin_teardown(opqst_t st) { hs_exit(); }
+
+const char msg[] =
+    "Wetterhorn Plugin v 0.01\n"
+    " This is a mere shared object file, meant to be a plugin for the "
+    "Wetterhorn"
+    " Compositor. To use this, please run 'wtr_harness -p [this_file]' to"
+    " use this plugin.\n";
+const int msg_sz = sizeof(msg);
+
+
+__attribute__((naked)) void _start() {
+
+  // Make system call to print the message
+  asm(
+      // Load the address of the string into rsi
+      "mov %0, %%rsi\n"
+      // Load the string length into edx
+      "mov %1, %%edx\n"
+      // Load the file descriptor for stdout into edi
+      "mov $1, %%edi\n"
+      // Load the syscall number for sys_write into eax
+      "mov $1, %%eax\n"
+      // Make the syscall
+      "syscall\n"
+
+      // Exit the program.
+      "mov $0, %%rdi\n"
+      "mov $60, %%rax\n"
+      "syscall\n"
+      :
+      : "r"(msg), "r"(msg_sz)  // Input: address of msg
+      : "%rsi", "%edx", "%edi" // Clobbered registers
+  );
+}