+
+static void change_root(void)
+{
+ if (chroot_dir) {
+ if (chroot(chroot_dir) < 0) {
+ fprintf(stderr, "chroot failed\n");
+ exit(1);
+ }
+ if (chdir("/")) {
+ perror("not able to chdir to /");
+ exit(1);
+ }
+ }
+
+}
+
+void os_daemonize(void)
+{
+ if (daemonize) {
+ pid_t pid;
+
+ if (pipe(fds) == -1)
+ exit(1);
+
+ pid = fork();
+ if (pid > 0) {
+ uint8_t status;
+ ssize_t len;
+
+ close(fds[1]);
+
+ again:
+ len = read(fds[0], &status, 1);
+ if (len == -1 && (errno == EINTR))
+ goto again;
+
+ if (len != 1)
+ exit(1);
+ else if (status == 1) {
+ fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno));
+ exit(1);
+ } else
+ exit(0);
+ } else if (pid < 0)
+ exit(1);
+
+ close(fds[0]);
+ qemu_set_cloexec(fds[1]);
+
+ setsid();
+
+ pid = fork();
+ if (pid > 0)
+ exit(0);
+ else if (pid < 0)
+ exit(1);
+
+ umask(027);
+
+ signal(SIGTSTP, SIG_IGN);
+ signal(SIGTTOU, SIG_IGN);
+ signal(SIGTTIN, SIG_IGN);
+ }
+}
+
+void os_setup_post(void)
+{
+ int fd = 0;
+
+ if (daemonize) {
+ uint8_t status = 0;
+ ssize_t len;
+
+ again1:
+ len = write(fds[1], &status, 1);
+ if (len == -1 && (errno == EINTR))
+ goto again1;
+
+ if (len != 1)
+ exit(1);
+
+ if (chdir("/")) {
+ perror("not able to chdir to /");
+ exit(1);
+ }
+ TFR(fd = qemu_open("/dev/null", O_RDWR));
+ if (fd == -1)
+ exit(1);
+ }
+
+ change_root();
+ change_process_uid();
+
+ if (daemonize) {
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+
+ close(fd);
+ }
+}
+
+void os_pidfile_error(void)
+{
+ if (daemonize) {
+ uint8_t status = 1;
+ if (write(fds[1], &status, 1) != 1) {
+ perror("daemonize. Writing to pipe\n");
+ }
+ } else
+ fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
+}
+
+void os_set_line_buffering(void)
+{
+ setvbuf(stdout, NULL, _IOLBF, 0);
+}
+
+/*
+ * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.
+ */
+int qemu_eventfd(int fds[2])
+{
+#ifdef CONFIG_EVENTFD
+ int ret;
+
+ ret = eventfd(0, 0);
+ if (ret >= 0) {
+ fds[0] = ret;
+ qemu_set_cloexec(ret);
+ if ((fds[1] = dup(ret)) == -1) {
+ close(ret);
+ return -1;
+ }
+ qemu_set_cloexec(fds[1]);
+ return 0;
+ }
+
+ if (errno != ENOSYS) {
+ return -1;
+ }
+#endif
+
+ return qemu_pipe(fds);
+}
+
+int qemu_create_pidfile(const char *filename)
+{
+ char buffer[128];
+ int len;
+ int fd;
+
+ fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);
+ if (fd == -1) {
+ return -1;
+ }
+ if (lockf(fd, F_TLOCK, 0) == -1) {
+ return -1;
+ }
+ len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid());
+ if (write(fd, buffer, len) != len) {
+ return -1;
+ }
+
+ return 0;
+}
+
+int qemu_get_thread_id(void)
+{
+#if defined (__linux__)
+ return syscall(SYS_gettid);
+#else
+ return getpid();
+#endif
+}