From 43cd776d7dc8ac573262f8459edeb1c1f5f3cd09 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 7 Mar 2024 16:18:32 -0500
Subject: xtime: Call tzset() from main() instead of lazily

POSIX specifies[1] that

    If a thread accesses tzname, daylight, or timezone directly while
    another thread is in a call to tzset(), or to any function that is
    required or allowed to set timezone information as if by calling
    tzset(), the behavior is undefined.

So calling it lazily from arbitrary threads is risky.

[1]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/tzset.html
---
 tests/bfstd.c  |  5 -----
 tests/main.c   | 14 ++++++++++++++
 tests/xtime.c  | 10 ++--------
 tests/xtouch.c |  2 ++
 4 files changed, 18 insertions(+), 13 deletions(-)

(limited to 'tests')

diff --git a/tests/bfstd.c b/tests/bfstd.c
index 4d0ec23..0ded5de 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -43,11 +43,6 @@ static bool check_wordesc(const char *str, const char *exp, enum wesc_flags flag
 bool check_bfstd(void) {
 	bool ret = true;
 
-	// Try to set a UTF-8 locale
-	if (!setlocale(LC_ALL, "C.UTF-8")) {
-		setlocale(LC_ALL, "");
-	}
-
 	// From man 3p basename
 	ret &= check_base_dir("usr", ".", "usr");
 	ret &= check_base_dir("usr/", ".", "usr");
diff --git a/tests/main.c b/tests/main.c
index e69fe35..38438b2 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -11,9 +11,11 @@
 #include "../src/config.h"
 #include "../src/diag.h"
 #include <errno.h>
+#include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 /**
  * Test context.
@@ -90,6 +92,18 @@ static void run_test(struct test_ctx *ctx, const char *test, test_fn *fn) {
 }
 
 int main(int argc, char *argv[]) {
+	// Try to set a UTF-8 locale
+	if (!setlocale(LC_ALL, "C.UTF-8")) {
+		setlocale(LC_ALL, "");
+	}
+
+	// Run tests in UTC
+	if (setenv("TZ", "UTC0", true) != 0) {
+		perror("setenv()");
+		return EXIT_FAILURE;
+	}
+	tzset();
+
 	struct test_ctx ctx;
 	if (test_init(&ctx, argc, argv) != 0) {
 		goto done;
diff --git a/tests/xtime.c b/tests/xtime.c
index f853428..2609c1c 100644
--- a/tests/xtime.c
+++ b/tests/xtime.c
@@ -81,8 +81,8 @@ static bool check_xgetdate(void) {
 /** Check one xmktime() result. */
 static bool check_one_xmktime(time_t expected) {
 	struct tm tm;
-	if (xlocaltime(&expected, &tm) != 0) {
-		bfs_diag("xlocaltime(%jd): %s", (intmax_t)expected, xstrerror(errno));
+	if (!localtime_r(&expected, &tm)) {
+		bfs_diag("localtime_r(%jd): %s", (intmax_t)expected, xstrerror(errno));
 		return false;
 	}
 
@@ -145,12 +145,6 @@ static bool check_xtimegm(void) {
 }
 
 bool check_xtime(void) {
-	if (setenv("TZ", "UTC0", true) != 0) {
-		perror("setenv()");
-		return false;
-	}
-	tzset();
-
 	bool ret = true;
 	ret &= check_xgetdate();
 	ret &= check_xmktime();
diff --git a/tests/xtouch.c b/tests/xtouch.c
index 6099128..8c5c5f3 100644
--- a/tests/xtouch.c
+++ b/tests/xtouch.c
@@ -157,6 +157,8 @@ done:
 }
 
 int main(int argc, char *argv[]) {
+	tzset();
+
 	mode_t mask = umask(0);
 
 	struct args args = {
-- 
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