Use argument results to decide whether or not to read stack_argument.

test/integration-ebpf/src/stack_argument.rs

@@ -12,14 +12,30 @@ static ARGS: HashMap<u32, u64> = HashMap::with_max_entries(24, 0);
 
 #[uprobe]
 pub fn test_stack_argument(ctx: ProbeContext) -> i32 {
-    match try_stack_argument(ctx) {
-        Ok(ret) => ret,
-        Err(_) => 0,
-    }
+    try_stack_argument(ctx).unwrap_or(0)
 }
 
 // read function arguments, and set to map.
 fn try_stack_argument(ctx: ProbeContext) -> Result<i32, i64> {
+    let mut stack = false;
+    let mut arg = 0;
+    loop {
+        if arg > 7 {
+            break;
+        }
+        if stack {
+            let _ = ARGS.insert(&arg, &ctx.arg(arg as usize).ok_or(255)?, 0);
+        } else {
+            let arg_v: Option<u64> = ctx.arg(arg as usize);
+            if let None = arg_v {
+                // assume that we shall read from stack now.
+                stack = true;
+                continue;
+            }
+            let _ = ARGS.insert(&arg, &arg_v.unwrap(), 0);
+        }
+        arg += 1;
+    }
     let _ = ARGS.insert(&0, &ctx.arg(0).ok_or(255)?, 0);
     let _ = ARGS.insert(&1, &ctx.arg(1).ok_or(255)?, 0);
     let _ = ARGS.insert(&2, &ctx.arg(2).ok_or(255)?, 0);