From ac1efb50d1e4d5ac04968cffefa5464b1511743c Mon Sep 17 00:00:00 2001
From: benbuckman <ben@benbuckman.net>
Date: Mon, 11 Nov 2019 14:20:44 -0800
Subject: [PATCH] ArgumentError on interval <1 or >1m

Addresses https://github.com/tmm1/stackprof/issues/125
---
 ext/stackprof/stackprof.c | 5 +++++
 test/test_stackprof.rb    | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/ext/stackprof/stackprof.c b/ext/stackprof/stackprof.c
index ae3467d4..c6c18214 100644
--- a/ext/stackprof/stackprof.c
+++ b/ext/stackprof/stackprof.c
@@ -16,6 +16,7 @@
 #include <pthread.h>
 
 #define BUF_SIZE 2048
+#define MICROSECONDS_IN_SECOND 1000000
 
 typedef struct {
     size_t total_samples;
@@ -92,6 +93,10 @@ stackprof_start(int argc, VALUE *argv, VALUE self)
     }
     if (!RTEST(mode)) mode = sym_wall;
 
+    if (!NIL_P(interval) && (NUM2INT(interval) < 1 || NUM2INT(interval) >= MICROSECONDS_IN_SECOND)) {
+        rb_raise(rb_eArgError, "interval is a number of microseconds between 1 and 1 million");
+    }
+
     if (!_stackprof.frames) {
 	_stackprof.frames = st_init_numtable();
 	_stackprof.overall_signals = 0;
diff --git a/test/test_stackprof.rb b/test/test_stackprof.rb
index 27da5c37..f8b4f65f 100644
--- a/test/test_stackprof.rb
+++ b/test/test_stackprof.rb
@@ -194,6 +194,15 @@ def test_pathname_out
     refute_empty profile[:frames]
   end
 
+  def test_min_max_interval
+    [-1, 0, 1_000_000, 1_000_001].each do |invalid_interval|
+      err = assert_raises(ArgumentError, "invalid interval #{invalid_interval}") do
+        StackProf.run(interval: invalid_interval, debug: true) {}
+      end
+      assert_match(/microseconds/, err.message)
+    end
+  end
+
   def math
     250_000.times do
       2 ** 10