1 files changed, 31 insertions, 0 deletions
diff --git a/src/fish.cpp b/src/fish.cpp
index 45899866..9482bd3f 100644
--- a/src/fish.cpp
+++ b/src/fish.cpp
@@ -407,6 +407,36 @@ static int fish_parse_opt(int argc, char **argv, std::vector<std::string> *cmds)
     return optind;
 }
 
+/// Various things we need to initialize at run-time that don't really fit any of the other init
+/// routines.
+static void misc_init() {
+#ifdef OS_IS_CYGWIN
+    // MS Windows tty devices do not have either a read or write timestamp. Those respective fields
+    // of `struct stat` are always the current time. Which means we can't use them. So we assume no
+    // external program has written to the terminal behind our back. This makes multiline prompts
+    // usable. See issue #2859.
+    has_working_tty_timestamps = false;
+#else
+    // This covers Windows Subsystem for Linux (WSL).
+    int fd = open("/proc/sys/kernel/osrelease", O_RDONLY);
+    if (fd != -1) {
+        const char *magic_suffix = "Microsoft";
+        int len_magic_suffix = strlen(magic_suffix);
+        char osrelease[128] = {0};
+        int len_osrelease = read(fd, osrelease, sizeof(osrelease) - 1);
+        if (osrelease[len_osrelease - 1] == '\n') {
+            osrelease[len_osrelease - 1] = '\0';
+            len_osrelease--;
+        }
+        if (len_osrelease >= len_magic_suffix &&
+            strcmp(magic_suffix, osrelease + len_osrelease - len_magic_suffix) == 0) {
+            has_working_tty_timestamps = false;
+        }
+        close(fd);
+    }
+#endif  // OS_IS_MS_WINDOWS
+}
+
 int main(int argc, char **argv) {
     int res = 1;
     int my_optind = 0;
@@ -452,6 +482,7 @@ int main(int argc, char **argv) {
     history_init();
     // For set_color to support term256 in config.fish (issue #1022).
     update_fish_color_support();
+    misc_init();
 
     parser_t &parser = parser_t::principal_parser();