fix(userspace/falco): timer_delete() workaround due to bug in older GLIBC

CHANGELOG.md

@@ -22,7 +22,7 @@ Released on 2023-09-26
 
 
 * new(falco-driver-loader): --source-only now prints the values as env vars [[#2353](https://github.com/falcosecurity/falco/pull/2353)] - [@steakunderscore](https://github.com/steakunderscore)
-* new(docker): allow passing options to falco-driver-loader from the driver loader cointainer [[#2781](https://github.com/falcosecurity/falco/pull/2781)] - [@LucaGuerra](https://github.com/LucaGuerra)
+* new(docker): allow passing options to falco-driver-loader from the driver loader container [[#2781](https://github.com/falcosecurity/falco/pull/2781)] - [@LucaGuerra](https://github.com/LucaGuerra)
 * new(docker): add experimental falco-distroless image based on Wolfi [[#2768](https://github.com/falcosecurity/falco/pull/2768)] - [@LucaGuerra](https://github.com/LucaGuerra)
 * new: the legacy falco image is available as driver-loader-legacy [[#2718](https://github.com/falcosecurity/falco/pull/2718)] - [@LucaGuerra](https://github.com/LucaGuerra)
 * new: added option to enable/disable echoing of server answer to stdout (disabled by default) when using HTTP output [[#2602](https://github.com/falcosecurity/falco/pull/2602)] - [@FedeDP](https://github.com/FedeDP)
@@ -1086,7 +1086,7 @@ Released on 2021-01-18
 ### Minor Changes
 
 * build: bump b64 to v2.0.0.1 [[#1441](https://github.com/falcosecurity/falco/pull/1441)] - [@fntlnz](https://github.com/fntlnz)
-* rules(macro container_started): re-use `spawned_process` macro inside `container_started` macro [[#1449](https://github.com/falcosecurity/falco/pull/1449)] - [@leodido](https://github.com/leodido)
+* rules(macro container_started): reuse `spawned_process` macro inside `container_started` macro [[#1449](https://github.com/falcosecurity/falco/pull/1449)] - [@leodido](https://github.com/leodido)
 * docs: reach out documentation [[#1472](https://github.com/falcosecurity/falco/pull/1472)] - [@fntlnz](https://github.com/fntlnz)
 * docs: Broken outputs.proto link [[#1493](https://github.com/falcosecurity/falco/pull/1493)] - [@deepskyblue86](https://github.com/deepskyblue86)
 * docs(README.md): correct broken links [[#1506](https://github.com/falcosecurity/falco/pull/1506)] - [@leogr](https://github.com/leogr)

proposals/20221129-artifacts-distribution.md

@@ -69,7 +69,7 @@ The allowed publishing channels are:
 Both channels are equivalent and may publish the same artifacts. However, for historical reasons and to avoid confusion, the **`docker.io` registry should only be used for container images** and not for other kinds of artifacts (e.g., plugins, rules, etc.).
 
 
-Mirrors are allowed and encouraged if they facilitate artifacts consumption by our users. This proposal reccomends to enable mirrors on the major public OCI registry, such as [Amazon ECR](https://gallery.ecr.aws/) (which is already implentend in our infra at the time of writing).
+Mirrors are allowed and encouraged if they facilitate artifacts consumption by our users. This proposal recommends to enable mirrors on the major public OCI registry, such as [Amazon ECR](https://gallery.ecr.aws/) (which is already implentend in our infra at the time of writing).
 
 
 Official **channels and mirrors must be listed at [falco.org](https://falco.org/)**. 

userspace/falco/atomic_signal_handler.h

@@ -87,9 +87,9 @@ namespace falco
         /**
          * @brief If a signal is triggered, performs an handler action.
          * The action function will be invoked exactly once among all the
-         * simultaneus calls. The action will not be performed if the
+         * simultaneous calls. The action will not be performed if the
          * signal is not triggered, or if the triggered has already been
-         * handled. When an action is being performed, all the simultaneus
+         * handled. When an action is being performed, all the simultaneous
          * callers will wait and be blocked up until its execution is finished.
          * If the handler action throws an exception, it will be considered
          * performed. After the first handler has been performed, every

userspace/falco/falco_outputs.h

@@ -36,7 +36,7 @@ limitations under the License.
 
 	All methods in this class are thread-safe. The output framework supports
 	a multi-producer model where messages are stored in a queue and consumed
-	by each configured output asynchrounously.
+	by each configured output asynchronously.
 */
 class falco_outputs
 {

userspace/falco/stats_writer.cpp

@@ -34,6 +34,12 @@ limitations under the License.
 // check that this value changed since their last observation.
 static std::atomic<stats_writer::ticker_t> s_timer((stats_writer::ticker_t) 0);
 static timer_t s_timerid;
+// note: Workaround for older GLIBC versions (< 2.35), where calling timer_delete() 
+// with an invalid timer ID not returned by timer_create() causes a segfault because of 
+// a bug in GLIBC (https://sourceware.org/bugzilla/show_bug.cgi?id=28257).
+// Just performing a nullptr check is not enough as even after creating the timer, s_timerid
+// remains a nullptr somehow.
+bool s_timerid_exists = false;
 
 static void timer_handler(int signum)
 {
@@ -60,18 +66,31 @@ bool stats_writer::init_ticker(uint32_t interval_msec, std::string &err)
 	sev.sigev_value.sival_ptr = &s_timerid;
 #ifndef __EMSCRIPTEN__
 	// delete any previously set timer
-	timer_delete(s_timerid);
-	if (timer_create(CLOCK_MONOTONIC, &sev, &s_timerid) == -1) {
+	if (s_timerid_exists)
+	{
+		if (timer_delete(s_timerid) == -1) 
+		{
+			err = std::string("Could not delete previous timer: ") + strerror(errno);
+			return false;
+		}
+		s_timerid_exists = false;
+	}
+
+	if (timer_create(CLOCK_MONOTONIC, &sev, &s_timerid) == -1) 
+	{
 		err = std::string("Could not create periodic timer: ") + strerror(errno);
 		return false;
 	}
+	s_timerid_exists = true;
+
 #endif
 	timer.it_value.tv_sec = interval_msec / 1000;
 	timer.it_value.tv_nsec = (interval_msec % 1000) * 1000 * 1000;
 	timer.it_interval = timer.it_value;
 
 #ifndef __EMSCRIPTEN__
-	if (timer_settime(s_timerid, 0, &timer, NULL) == -1) {
+	if (timer_settime(s_timerid, 0, &timer, NULL) == -1) 
+	{
 		err = std::string("Could not set up periodic timer: ") + strerror(errno);
 		return false;
 	}
@@ -134,7 +153,11 @@ stats_writer::~stats_writer()
 		}
 		// delete timerID and reset timer
 #ifndef __EMSCRIPTEN__
-		timer_delete(s_timerid);
+		if (s_timerid_exists)
+		{
+			timer_delete(s_timerid);
+			s_timerid_exists = false;
+		}
 #endif
 	}
 }