+
+int daemon_detach(void)
+{
+ pid_t pid;
+
+ close(STDIN_FILENO);
+ close(STDOUT_FILENO);
+ close(STDERR_FILENO);
+
+ open("/dev/null", O_RDWR);
+ open("/dev/null", O_RDWR);
+ open("/dev/null", O_RDWR);
+
+ pid = fork();
+ if (pid < 0)
+ return -1;
+ if (pid)
+ exit(0);
+
+ setsid();
+ return 0;
+}
+
+int drop_privileges(const char *user, const char *group)
+{
+ if (!geteuid()) {
+ struct passwd *pw;
+ struct group *gr;
+
+ if (group) {
+ gr = getgrnam(group);
+ if (!gr)
+ return -1;
+ setgid(gr->gr_gid);
+ }
+
+ pw = getpwnam(user);
+ if (!pw)
+ return -1;
+ if (!group) {
+ setgid(pw->pw_gid);
+ }
+ setuid(pw->pw_uid);
+ }
+
+ return 0;
+}
+
+extern initcall_t __madinit[], __madexit[];
+
+static void common_shutdown(void)
+{
+ for (int i = -1; __madexit[i]; i--) {
+ (*__madexit[i])();
+ }
+}
+
+static void __attribute__((__constructor__,__used__))
+common_initialize(void)
+{
+ if (atexit(common_shutdown)) {
+ fputs("Cannot hook my atexit function, quitting !\n", stderr);
+ abort();
+ }
+
+ for (int i = 0; __madinit[i]; i++) {
+ if ((*__madinit[i])()) {
+ exit(EXIT_FAILURE);
+ }
+ }
+}
+