Daemonize test.

ccan/daemonize/test/run.c

+#include <ccan/daemonize/daemonize.h>
+#include <ccan/daemonize/daemonize.c>
+#include <ccan/tap/tap.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <err.h>
+#include <errno.h>
+
+struct child_data {
+	pid_t pid;
+	pid_t ppid;
+	bool in_root_dir;
+	int read_from_stdin, write_to_stdout, write_to_stderr;
+};
+
+int main(int argc, char *argv[])
+{
+	int fds[2];
+	struct child_data daemonized;
+	pid_t pid;
+
+	plan_tests(6);
+
+	if (pipe(fds) != 0)
+		err(1, "Failed pipe");
+
+	/* Since daemonize forks and parent exits, we need to fork
+	 * that parent. */
+	pid = fork();
+	if (pid == -1)
+		err(1, "Failed fork");
+
+	if (pid == 0) {
+		char buffer[2];
+		pid = getpid();
+		daemonize();
+		daemonized.pid = getpid();
+		daemonized.in_root_dir = (getcwd(buffer, 2) != NULL);
+		daemonized.read_from_stdin
+			= read(STDIN_FILENO, buffer, 1) == -1 ? errno : 0;
+		daemonized.write_to_stdout
+			= write(STDOUT_FILENO, buffer, 1) == -1 ? errno : 0;
+		daemonized.write_to_stderr
+			= write(STDERR_FILENO, buffer, 1) == -1 ? errno : 0;
+
+		/* Make sure parent exits. */
+		while (getppid() == pid)
+			sleep(1);
+		daemonized.ppid = getppid();
+		write(fds[1], &daemonized, sizeof(daemonized));
+		exit(0);
+	}
+
+	if (read(fds[0], &daemonized, sizeof(daemonized)) != sizeof(daemonized))
+		err(1, "Failed read");
+
+	ok1(daemonized.pid != pid);
+	ok1(daemonized.ppid == 1);
+	ok1(daemonized.in_root_dir);
+	ok1(daemonized.read_from_stdin == EBADF);
+	ok1(daemonized.write_to_stdout == EBADF);
+	ok1(daemonized.write_to_stderr == EBADF);
+
+	return exit_status();
+}