+
+bool is_valid_documentation_url(const char *url) {
+ assert(url);
+
+ if (startswith(url, "http://") && url[7])
+ return true;
+
+ if (startswith(url, "https://") && url[8])
+ return true;
+
+ if (startswith(url, "file:") && url[5])
+ return true;
+
+ if (startswith(url, "info:") && url[5])
+ return true;
+
+ if (startswith(url, "man:") && url[4])
+ return true;
+
+ return false;
+}
+
+bool in_initrd(void) {
+ static int saved = -1;
+
+ if (saved < 0)
+ saved = access("/etc/initrd-release", F_OK) >= 0;
+
+ return saved;
+}
+
+void warn_melody(void) {
+ int fd;
+
+ fd = open("/dev/console", O_WRONLY|O_CLOEXEC|O_NOCTTY);
+ if (fd < 0)
+ return;
+
+ /* Yeah, this is synchronous. Kinda sucks. Bute well... */
+
+ ioctl(fd, KIOCSOUND, (int)(1193180/440));
+ usleep(125*USEC_PER_MSEC);
+
+ ioctl(fd, KIOCSOUND, (int)(1193180/220));
+ usleep(125*USEC_PER_MSEC);
+
+ ioctl(fd, KIOCSOUND, (int)(1193180/220));
+ usleep(125*USEC_PER_MSEC);
+
+ ioctl(fd, KIOCSOUND, 0);
+ close_nointr_nofail(fd);
+}