Add a small multithreading test case

This adds a test case that just spawns a bunch of threads quickly and
calls efi_get_variable() on an empty directory.  It fails pretty
reliably without either of the following commits:

65a3ad0 error.c: make our 'global' state be thread local
3d19e7d efivarfs.c: Call get_efivarfs_path() from a constructor

Signed-off-by: Peter Jones <pjones@redhat.com>

.gitignore

@@ -11,7 +11,6 @@
 *.map
 *.pc
 *.S
-!src/guids.S
 *.so
 *.so.*
 *.spec
@@ -22,7 +21,3 @@ core.*
 cov-int
 vgcore.*
 scan-results/
-src/efivar
-src/efivar-static
-src/makeguids
-src/guid-symbols.c

src/.gitignore

@@ -1,2 +1,8 @@
+!guids.S
 *.bin
+efivar
 efivar-guids.h
+efivar-static
+makeguids
+guid-symbols.c
+thread-test

src/Makefile

@@ -7,7 +7,7 @@ include $(TOPDIR)/src/include/defaults.mk
 
 LIBTARGETS=libefivar.so libefiboot.so
 STATICLIBTARGETS=libefivar.a libefiboot.a
-BINTARGETS=efivar
+BINTARGETS=efivar thread-test
 STATICBINTARGETS=efivar-static
 PCTARGETS=efivar.pc efiboot.pc
 TARGETS=$(LIBTARGETS) $(BINTARGETS) $(PCTARGETS)
@@ -86,6 +86,10 @@ libefiboot.so : | libefiboot.map libefivar.so
 libefiboot.so : LIBS=efivar
 libefiboot.so : MAP=libefiboot.map
 
+thread-test : thread-test.o
+thread-test : CFLAGS=$(HOST_CFLAGS) -I$(TOPDIR)/src/include/efivar
+thread-test : LIBS=pthread efivar
+
 deps : $(ALL_SOURCES)
 	@$(MAKE) -f $(SRCDIR)/include/deps.mk deps SOURCES="$(ALL_SOURCES)"
 

src/thread-test.c

@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/*
+ * thread-test.c - test (some) efivar thread safety
+ * Copyright Jonathan Marler
+ */
+
+#include <alloca.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+// returns: the number of threads created
+static size_t
+multi_pthread_create(pthread_t * threads, unsigned count,
+		     void *(*start_routine)(void *))
+{
+	size_t i = 0;
+	int result;
+
+	for (; i < count; i++) {
+		result = pthread_create(&threads[i], NULL, start_routine, NULL);
+		if (result != 0) {
+			perror("pthread_create");
+			break;
+		}
+	}
+
+	return i;
+}
+
+#define TEST_SUCCESS NULL
+#define TEST_FAIL ((void*)1)
+static const char *test_result_str(void *result)
+{
+	return (result == TEST_SUCCESS) ? "SUCCESS" : "FAIL";
+}
+
+// returns: 0 on success
+static int
+multi_pthread_join(pthread_t * threads, unsigned count, void **worst_result)
+{
+	for (unsigned i = 0; i < count; i++) {
+		void *result;
+		int join_result;
+
+		join_result = pthread_join(threads[i], &result);
+		if (join_result != 0) {
+			perror("pthread_join");
+			return 1;
+		}
+		printf("[MAIN-THREAD] child %d exited with %s\n", i,
+		       test_result_str(result));
+		if (result != NULL) {
+			*worst_result = result;
+		}
+	}
+	return 0;
+}
+
+#include <efivar.h>
+#define LOOP_COUNT 100
+
+static void *loop_get_variable_size_test(void *_ __attribute__((__unused__)))
+{
+	//printf("[DEBUG] test running on new thread!\n");
+	for (unsigned i = 0; i < LOOP_COUNT; i++) {
+		size_t size;
+		efi_guid_t guid = { 0 };
+		int result;
+
+		result = efi_get_variable_size(guid, "foo2", &size);
+		if (result == 0 || errno != ENOENT) {
+			printf("fail, iteration=%u, result=%d errno=%d, expected error\n",
+			       i, result, errno);
+			return TEST_FAIL;
+		} else {
+			//printf("[DEBUG] iteration=%u, result=%d errno=%d\n", i, result, errno);
+		}
+	}
+	return TEST_SUCCESS;
+}
+
+static int multithreaded_test(size_t count, void *(*test_func)(void *))
+{
+	pthread_t *threads = alloca(sizeof(pthread_t) * count);
+	if (count != multi_pthread_create(threads, count, test_func)) {
+		// error already logged
+		return 1;
+	}
+	void *worst_result = TEST_SUCCESS;
+	if (multi_pthread_join(threads, count, &worst_result)) {
+		// error already logged
+		return 1;
+	}
+	printf("worst result %s\n", test_result_str(worst_result));
+	return (worst_result == TEST_SUCCESS) ? 0 : -1;
+}
+
+int main(int argc, char *argv[])
+{
+	int thread_count;
+
+	if (argc != 2) {
+		printf("Usage: %s THREAD_COUNT\n", argv[0]);
+		return 1;
+	}
+
+	thread_count = atoi(argv[1]);
+	printf("thread count %d\n", thread_count);
+	return multithreaded_test(thread_count, loop_get_variable_size_test);
+}
+
+// vim:fenc=utf-8:tw=75:noet

tests/Makefile

@@ -3,7 +3,7 @@
 # Peter Jones, 2019-06-18 11:10
 #
 
-all: clean test0 test1 test2 test3 test4
+all: clean test0 test1 test2 test3 test4 test5
 
 GRUB_PREFIX ?= grub2
 EFIVAR ?= $(TOPDIR)/src/efivar
@@ -80,6 +80,10 @@ test4:
 	@rm test.4.0.result.var test.4.1.result.var
 	@echo passed
 
+test5:
+	@echo testing threading in libefivar
+	@TOPDIR=$(TOPDIR) $(TOPDIR)/tests/test-threading
+
 .PHONY: all clean test0
 # vim:ft=make
 #

tests/test-threading

@@ -0,0 +1,40 @@
+#!/usr/bin/env sh
+# SPDX-License-Identifier: LGPL-2.1-or-later
+# test (some) efivar thread safety
+#
+# Copyright Jonathan Marler
+
+set -e
+
+if [ "x$TOPDIR" = "x" ] ; then
+	TOPDIR="$(realpath "$(dirname "$0")/../")"
+fi
+
+rm -rf scratch
+mkdir scratch
+
+EFIVARFS_PATH=""
+LD_LIBRARY_PATH=""
+LIBEFIVAR_OPS=""
+
+EFIVARFS_PATH=$(realpath scratch)/
+LD_LIBRARY_PATH="${TOPDIR}/src/"
+LIBEFIVAR_OPS=efivarfs
+export EFIVARFS_PATH LD_LIBRARY_PATH LIBEFIVAR_OPS
+
+test() {
+	echo "================================================================================"
+	echo "testing $1 thread..."
+	echo "================================================================================"
+	if "${TOPDIR}/src/thread-test" "$1" ; then
+		echo "${1} thread worked"
+	else
+		echo "${1} thread failed"
+		exit 1
+	fi
+}
+
+test 1
+test 2
+test 4
+test 64