linux: use TMPDIR to store icons if defined

TMPDIR is the canonical environment variable in Unix and POSIX that
should be used to specify a temporary directory:
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03

Let's use it if is defined to store temporary icon files and default to
'/tmp' if is not defined.

1 files changed, 9 insertions, 2 deletions

diff --git a/systray_linux.c b/systray_linux.c
index 3ed8ada..7ed58cd 100644
--- a/systray_linux.c
+++ b/systray_linux.c
@@ -48,9 +48,16 @@ void _unlink_temp_file() {
 
 // runs in main thread, should always return FALSE to prevent gtk to execute it again
 gboolean do_set_icon(gpointer data) {
-	GBytes* bytes = (GBytes*)data;
 	_unlink_temp_file();
-	strcpy(temp_file_name, "/tmp/systray_XXXXXX");
+	char *tmpdir = getenv("TMPDIR");
+	if (NULL == tmpdir) {
+		tmpdir = "/tmp";
+	}
+	strncpy(temp_file_name, tmpdir, PATH_MAX-1);
+	strncat(temp_file_name, "/systray_XXXXXX", PATH_MAX-1);
+	temp_file_name[PATH_MAX-1] = '\0';
+
+	GBytes* bytes = (GBytes*)data;
 	int fd = mkstemp(temp_file_name);
 	if (fd == -1) {
 		printf("failed to create temp icon file %s: %s\n", temp_file_name, strerror(errno));