Add a utility function to resolve TTY color escape codes dynamically

src/libstrongswan/utils/utils.c

@@ -194,6 +194,69 @@ bool mkdir_p(const char *path, mode_t mode)
 	return TRUE;
 }
 
+ENUM(tty_color_names, TTY_RESET, TTY_BG_DEF,
+	"\e[0m",
+	"\e[1m",
+	"\e[4m",
+	"\e[5m",
+	"\e[30m",
+	"\e[31m",
+	"\e[32m",
+	"\e[33m",
+	"\e[34m",
+	"\e[35m",
+	"\e[36m",
+	"\e[37m",
+	"\e[39m",
+	"\e[40m",
+	"\e[41m",
+	"\e[42m",
+	"\e[43m",
+	"\e[44m",
+	"\e[45m",
+	"\e[46m",
+	"\e[47m",
+	"\e[49m",
+);
+
+/**
+ * Get the escape string for a given TTY color, empty string on non-tty FILE
+ */
+char* tty_escape_get(int fd, tty_escape_t escape)
+{
+	if (!isatty(fd))
+	{
+		return "";
+	}
+	switch (escape)
+	{
+		case TTY_RESET:
+		case TTY_BOLD:
+		case TTY_UNDERLINE:
+		case TTY_BLINKING:
+		case TTY_FG_BLACK:
+		case TTY_FG_RED:
+		case TTY_FG_GREEN:
+		case TTY_FG_YELLOW:
+		case TTY_FG_BLUE:
+		case TTY_FG_MAGENTA:
+		case TTY_FG_CYAN:
+		case TTY_FG_WHITE:
+		case TTY_FG_DEF:
+		case TTY_BG_BLACK:
+		case TTY_BG_RED:
+		case TTY_BG_GREEN:
+		case TTY_BG_YELLOW:
+		case TTY_BG_BLUE:
+		case TTY_BG_MAGENTA:
+		case TTY_BG_CYAN:
+		case TTY_BG_WHITE:
+		case TTY_BG_DEF:
+			return enum_to_name(tty_color_names, escape);
+		/* warn if a excape code is missing */
+	}
+	return "";
+}
 
 /**
  * The size of the thread-specific error buffer

src/libstrongswan/utils/utils.h

@@ -314,6 +314,46 @@ enum status_t {
  */
 extern enum_name_t *status_names;
 
+typedef enum tty_escape_t tty_escape_t;
+
+/**
+ * Excape codes for tty colors
+ */
+enum tty_escape_t {
+	/** text properties */
+	TTY_RESET,
+	TTY_BOLD,
+	TTY_UNDERLINE,
+	TTY_BLINKING,
+
+	/** foreground colors */
+	TTY_FG_BLACK,
+	TTY_FG_RED,
+	TTY_FG_GREEN,
+	TTY_FG_YELLOW,
+	TTY_FG_BLUE,
+	TTY_FG_MAGENTA,
+	TTY_FG_CYAN,
+	TTY_FG_WHITE,
+	TTY_FG_DEF,
+
+	/** background colors */
+	TTY_BG_BLACK,
+	TTY_BG_RED,
+	TTY_BG_GREEN,
+	TTY_BG_YELLOW,
+	TTY_BG_BLUE,
+	TTY_BG_MAGENTA,
+	TTY_BG_CYAN,
+	TTY_BG_WHITE,
+	TTY_BG_DEF,
+};
+
+/**
+ * Get the escape string for a given TTY color, empty string on non-tty fd
+ */
+char* tty_escape_get(int fd, tty_escape_t escape);
+
 /**
  * deprecated pluto style return value:
  * error message, NULL for success