builtin/bugreport.c: use thread-safe localtime_r()

ttaylorr · gitster · commit 4f6460df55cd · 2020-12-01T13:05:37.000-08:00
To generate its filename, the 'git bugreport' builtin asks the system
for the current time with 'localtime()'. Since this uses a shared
buffer, it is not thread-safe.

Even though 'git bugreport' is not multi-threaded, using localtime() can
trigger some static analysis tools to complain, and a quick

    $ git grep -oh 'localtime$_.$\?' -- **/*.c | sort | uniq -c

shows that the only usage of the thread-unsafe 'localtime' is in a piece
of documentation.

So, convert this instance to use the thread-safe version for
consistency, and to appease some analysis tools.

Signed-off-by: Taylor Blau &lt;me@ttaylorr.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/builtin/bugreport.c b/builtin/bugreport.c
@@ -125,6 +125,7 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
 	struct strbuf report_path = STRBUF_INIT;
 	int report = -1;
 	time_t now = time(NULL);
+	struct tm tm;
 	char *option_output = NULL;
 	char *option_suffix = "%Y-%m-%d-%H%M";
 	const char *user_relative_path = NULL;
@@ -147,7 +148,7 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
 	strbuf_complete(&report_path, '/');
 
 	strbuf_addstr(&report_path, "git-bugreport-");
-	strbuf_addftime(&report_path, option_suffix, localtime(&now), 0, 0);
+	strbuf_addftime(&report_path, option_suffix, localtime_r(&now, &tm), 0, 0);
 	strbuf_addstr(&report_path, ".txt");
 
 	switch (safe_create_leading_directories(report_path.buf)) {
