From c550ab7aa40a7ef42ebf29c759af09768d4e2736 Mon Sep 17 00:00:00 2001
From: Mattia Meleleo <mattia.meleleo@elastic.co>
Date: Thu, 11 Jan 2024 14:41:17 +0100
Subject: [PATCH] fix: race condition in EventsTrace ctx init

---
 non-GPL/Events/EventsTrace/EventsTrace.c      | 10 ++++++-
 testing/test_bins/create_rename_delete_file.c | 26 +++++++++++++++++--
 testing/testrunner/tests.go                   | 13 +++++++---
 3 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/non-GPL/Events/EventsTrace/EventsTrace.c b/non-GPL/Events/EventsTrace/EventsTrace.c
index a66321d7..2469346b 100644
--- a/non-GPL/Events/EventsTrace/EventsTrace.c
+++ b/non-GPL/Events/EventsTrace/EventsTrace.c
@@ -16,6 +16,7 @@
 #include <string.h>
 #include <sys/resource.h>
 #include <sys/time.h>
+#include <unistd.h>
 
 #include <arpa/inet.h>
 #include <netinet/in.h>
@@ -109,6 +110,7 @@ uint64_t g_events_env   = 0;
 uint64_t g_features_env = 0;
 
 bool g_print_features_init = 0;
+bool g_features_printed    = 0;
 bool g_unbuffer_stdout     = 0;
 bool g_libbpf_verbose      = 0;
 
@@ -859,6 +861,10 @@ static void out_network_connection_closed_event(struct ebpf_net_event *evt)
 
 static int event_ctx_callback(struct ebpf_event_header *evt_hdr)
 {
+    if (g_print_features_init)
+        while (!g_features_printed)
+            usleep(100000);
+
     switch (evt_hdr->type) {
     case EBPF_EVENT_PROCESS_FORK:
         out_process_fork((struct ebpf_process_fork_event *)evt_hdr);
@@ -945,8 +951,10 @@ int main(int argc, char **argv)
         goto out;
     }
 
-    if (g_print_features_init)
+    if (g_print_features_init) {
         print_init_msg(ebpf_event_ctx__get_features(ctx));
+        g_features_printed = 1;
+    }
 
     while (!exiting) {
         err = ebpf_event_ctx__next(ctx, 10);
diff --git a/testing/test_bins/create_rename_delete_file.c b/testing/test_bins/create_rename_delete_file.c
index 549ee881..f98a8418 100644
--- a/testing/test_bins/create_rename_delete_file.c
+++ b/testing/test_bins/create_rename_delete_file.c
@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <unistd.h>
 
 #include "common.h"
@@ -25,13 +26,34 @@ int main()
            filename_orig, filename_new);
 
     FILE *f;
+    // create
     CHECK(f = fopen(filename_orig, "w"), NULL);
 
+    // rename
     CHECK(rename(filename_orig, filename_new), -1);
+
+    // modify(permissions)
     CHECK(chmod(filename_new, S_IRWXU | S_IRWXG | S_IRWXO), -1);
-    CHECK(fprintf(f, "test"), -1);
-    CHECK(ftruncate(fileno(f), 0), -1);
+
+    int fd = fileno(f);
+
+    // modify(content)
+    CHECK(write(fd, "test", 4), -1);
+
+    // modify(content)
+    struct iovec iov[2];
+    iov[0].iov_base = "test2";
+    iov[0].iov_len  = 5;
+    iov[1].iov_base = "test3";
+    iov[1].iov_len  = 5;
+    CHECK(writev(fd, iov, 2), -1);
+
+    // modify(content)
+    CHECK(ftruncate(fd, 0), -1);
+
     CHECK(fclose(f), EOF);
+
+    // delete
     CHECK(unlink(filename_new), -1);
 
     return 0;
diff --git a/testing/testrunner/tests.go b/testing/testrunner/tests.go
index 71ab9476..a8a45710 100644
--- a/testing/testrunner/tests.go
+++ b/testing/testrunner/tests.go
@@ -215,7 +215,7 @@ func TestFileDelete(et *EventsTraceInstance) {
 	AssertStringsEqual(fileDeleteEvent.Finfo.Type, "FILE")
 	AssertUint64NotEqual(fileDeleteEvent.Finfo.Inode, 0)
 	AssertUint64Equal(fileDeleteEvent.Finfo.Mode, 100777)
-	AssertUint64Equal(fileDeleteEvent.Finfo.Size, 4)
+	AssertUint64Equal(fileDeleteEvent.Finfo.Size, 0)
 	AssertUint64Equal(fileDeleteEvent.Finfo.Uid, 0)
 	AssertUint64Equal(fileDeleteEvent.Finfo.Gid, 0)
 }
@@ -401,7 +401,7 @@ func TestFileModify(et *EventsTraceInstance) {
 		TestFail("failed to unmarshal json", err)
 	}
 
-	eventsCount := 3 // chmod, write, truncate
+	eventsCount := 4 // chmod, write, writev, truncate
 	events := make([]FileModifyEvent, 0, eventsCount)
 	for {
 		var event FileModifyEvent
@@ -427,12 +427,17 @@ func TestFileModify(et *EventsTraceInstance) {
 	// write
 	AssertStringsEqual(events[1].Path, binOutput.FileNameNew)
 	AssertStringsEqual(events[1].ChangeType, "CONTENT")
+	AssertUint64Equal(events[1].Finfo.Size, 4)
 
-	// truncate
+	// writev
 	AssertStringsEqual(events[2].Path, binOutput.FileNameNew)
 	AssertStringsEqual(events[2].ChangeType, "CONTENT")
+	AssertUint64Equal(events[2].Finfo.Size, 4+5+5)
 
-	AssertTrue(events[1].Finfo.Size != events[2].Finfo.Size)
+	// truncate
+	AssertStringsEqual(events[3].Path, binOutput.FileNameNew)
+	AssertStringsEqual(events[3].ChangeType, "CONTENT")
+	AssertUint64Equal(events[3].Finfo.Size, 0)
 }
 
 func TestTtyWrite(et *EventsTraceInstance) {