Add simple cron implementation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>

1 files changed, 87 insertions, 0 deletions

diff --git a/crond/runjob.c b/crond/runjob.c
new file mode 100644
index 0000000..7650748
--- /dev/null
+++ b/crond/runjob.c
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * Copyright (C) 2018 - David Oberhollenzer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include "gcrond.h"
+
+int runjob(crontab_t *tab)
+{
+	struct sigaction act;
+	pid_t pid;
+	exec_t *e;
+	int ret;
+
+	if (tab->exec == NULL)
+		return 0;
+
+	pid = fork();
+	if (pid == -1) {
+		perror("fork");
+		return -1;
+	}
+
+	if (pid != 0) {
+		tab->pid = pid;
+		return 0;
+	}
+
+	/* XXX: inside the child process */
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = SIG_DFL;
+	sigaction(SIGINT, &act, NULL);
+	sigaction(SIGTERM, &act, NULL);
+	sigaction(SIGHUP, &act, NULL);
+
+	if (setup_tty(tab->ctty, tab->tty_truncate))
+		exit(EXIT_FAILURE);
+
+	if (tab->gid != 0) {
+		if (setresgid(tab->gid, tab->gid, tab->gid)) {
+			perror("setgid");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (tab->uid != 0) {
+		if (setresuid(tab->uid, tab->uid, tab->uid)) {
+			perror("setuid");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (tab->exec->next == NULL)
+		argv_exec(tab->exec);
+
+	for (e = tab->exec; e != NULL; e = e->next) {
+		pid = fork();
+		if (pid == -1) {
+			perror("fork");
+			exit(EXIT_FAILURE);
+		}
+
+		if (pid == 0)
+			argv_exec(e);
+
+		while (waitpid(pid, &ret, 0) != pid)
+			;
+
+		ret = WIFEXITED(ret) ? WEXITSTATUS(ret) : EXIT_FAILURE;
+		if (ret != EXIT_SUCCESS)
+			break;
+	}
+
+	exit(ret);
+}