Add PAL version api

src/pal/include/occlum_pal_api.h

@@ -5,6 +5,18 @@
 extern "C" {
 #endif
 
+/*
+ * Occlum PAL API version number
+ */
+#define OCCLUM_PAL_VERSION 1
+
+/*
+ * @brief Get version of Occlum PAL API
+ *
+ * @retval If > 0, then success; otherwise, it is an invalid version.
+ */
+int occlum_pal_get_version(void);
+
 /*
  * Occlum PAL attributes
  */

src/pal/pal.lds

@@ -1,5 +1,6 @@
 {
     global:
+        occlum_pal_get_version;
         occlum_pal_init;
         occlum_pal_exec;
         occlum_pal_destroy;

src/pal/src/pal_api.c

@@ -6,6 +6,10 @@
 #include "pal_syscall.h"
 #include "errno2str.h"
 
+int occlum_pal_get_version(void) {
+    return OCCLUM_PAL_VERSION;
+}
+
 int occlum_pal_init(const struct occlum_pal_attr* attr) {
     errno = 0;
 

src/run/main.c

@@ -26,6 +26,12 @@ int main(int argc, char* argv[]) {
     const char* cmd_path = (const char*) argv[1];
     const char** cmd_args = (const char**) &argv[2];
 
+    // Check Occlum PAL version
+    int pal_version = occlum_pal_get_version();
+    if (pal_version <= 0) {
+        return EXIT_FAILURE;
+    }
+
     // Init Occlum PAL
     struct occlum_pal_attr attr = OCCLUM_PAL_ATTR_INITVAL;
     attr.instance_dir = get_instance_dir();