Add simple cron implementation

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

.gitignore

@@ -23,6 +23,7 @@ runsvc
 syslog
 usyslogd
 klogd
+gcrond
 
 services/sigkill
 services/sigterm

Makefile.am

@@ -20,6 +20,7 @@ dist_man8_MANS =
 include lib/Makemodule.am
 include cmd/Makemodule.am
 include initd/Makemodule.am
+include crond/Makemodule.am
 include scripts/Makemodule.am
 include services/Makemodule.am
 include syslogd/Makemodule.am
@@ -51,6 +52,10 @@ install-data-local:
 	$(LN_S) $(TEMPLATEDIR)/ifcfg $(DESTDIR)$(SVCDIR)/ifcfg
 	$(LN_S) $(TEMPLATEDIR)/modules $(DESTDIR)$(SVCDIR)/modules
 	$(LN_S) $(TEMPLATEDIR)/network $(DESTDIR)$(SVCDIR)/network
+if GCROND
+	$(MKDIR_P) $(DESTDIR)$(GCRONDIR)
+	$(LN_S) $(TEMPLATEDIR)/gcrond $(DESTDIR)$(SVCDIR)/gcrond
+endif
 if USYSLOGD
 	$(LN_S) $(TEMPLATEDIR)/usyslogd $(DESTDIR)$(SVCDIR)/usyslogd
 endif

cmd/runsvc/runsvc.c

@@ -17,51 +17,6 @@
  */
 #include "runsvc.h"
 
-static int setup_tty(service_t *svc)
-{
-	int fd;
-
-	if (svc->ctty != NULL) {
-		fd = open(svc->ctty, O_RDWR);
-		if (fd < 0) {
-			perror(svc->ctty);
-			return -1;
-		}
-
-		if (svc->flags & SVC_FLAG_TRUNCATE_OUT)
-			ftruncate(fd, 0);
-
-		close(STDIN_FILENO);
-		close(STDOUT_FILENO);
-		close(STDERR_FILENO);
-
-		setsid();
-
-		dup2(fd, STDIN_FILENO);
-		dup2(fd, STDOUT_FILENO);
-		dup2(fd, STDERR_FILENO);
-		close(fd);
-	}
-
-	return 0;
-}
-
-/*****************************************************************************/
-
-static NORETURN void argv_exec(exec_t *e)
-{
-	char **argv = alloca(e->argc + 1), *ptr;
-	int i;
-
-	for (ptr = e->args, i = 0; i < e->argc; ++i, ptr += strlen(ptr) + 1)
-		argv[i] = ptr;
-
-	argv[i] = NULL;
-	execvp(argv[0], argv);
-	perror(argv[0]);
-	exit(EXIT_FAILURE);
-}
-
 static int runlst_wait(exec_t *list)
 {
 	pid_t ret, pid;
@@ -128,7 +83,7 @@ int main(int argc, char **argv)
 	if (initenv())
 		goto out;
 
-	if (setup_tty(svc))
+	if (setup_tty(svc->ctty, (svc->flags & SVC_FLAG_TRUNCATE_OUT) != 0))
 		goto out;
 
 	if (svc->exec->next == NULL)

configure.ac

@@ -55,9 +55,19 @@ AC_ARG_WITH([klogd],
 	esac],
 	[AM_CONDITIONAL([KLOGD], [true])])
 
+AC_ARG_WITH([gcrond],
+	[AS_HELP_STRING([--without-gcrond], [Build without gcron daemon])],
+	[case "${withval}" in
+	yes) AM_CONDITIONAL([GCROND], [true]) ;;
+	no) AM_CONDITIONAL([GCROND], [false]) ;;
+	*) AC_MSG_ERROR([bad value ${withval} for --without-gcron]) ;;
+	esac],
+	[AM_CONDITIONAL([GCROND], [true])])
+
 
 AC_CONFIG_HEADERS([lib/include/config.h])
 AC_DEFINE_DIR(SVCDIR, sysconfdir/init.d, [Startup service directory])
+AC_DEFINE_DIR(GCRONDIR, sysconfdir/gcron.d, [Cron service directory])
 AC_DEFINE_DIR(TEMPLATEDIR, datadir/init, [Service template directory])
 AC_DEFINE_DIR(SCRIPTDIR, libexecdir/init, [Helper script directory])
 AC_DEFINE_DIR(SOCKDIR, localstatedir/run, [Directory for initd socket])

crond/Makemodule.am

@@ -0,0 +1,9 @@
+if GCROND
+gcrond_SOURCES = crond/main.c crond/gcrond.h crond/runjob.c
+gcrond_CPPFLAGS = $(AM_CPPFLAGS)
+gcrond_CFLAGS = $(AM_CFLAGS)
+gcrond_LDFLAGS = $(AM_LDFLAGS)
+gcrond_LDADD = libcron.a libinit.a libcfg.a
+
+sbin_PROGRAMS += gcrond
+endif

crond/gcrond.h

@@ -0,0 +1,37 @@
+/* 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/>.
+ */
+#ifndef GCROND_H
+#define GCROND_H
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "crontab.h"
+#include "config.h"
+#include "util.h"
+
+int runjob(crontab_t *tab);
+
+#endif /* GCROND_H */
+

crond/main.c

@@ -0,0 +1,139 @@
+/* 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"
+
+static crontab_t *jobs;
+static sig_atomic_t run = 1;
+static sig_atomic_t rescan = 1;
+
+static void read_config(void)
+{
+	if (cronscan(GCRONDIR, &jobs)) {
+		fputs("Error reading configuration. Continuing anyway.\n",
+		      stderr);
+	}
+}
+
+static void cleanup_config(void)
+{
+	crontab_t *t;
+
+	while (jobs != NULL) {
+		t = jobs;
+		jobs = jobs->next;
+		delcron(t);
+	}
+}
+
+static int calc_timeout(void)
+{
+	time_t now = time(NULL), future;
+	struct tm tmstruct;
+	crontab_t mask, *t;
+	int minutes;
+
+	for (minutes = 0; minutes < 120; ++minutes) {
+		future = now + minutes * 60;
+
+		localtime_r(&future, &tmstruct);
+		cron_tm_to_mask(&mask, &tmstruct);
+
+		for (t = jobs; t != NULL; t = t->next) {
+			if (cron_should_run(t, &mask))
+				goto out;
+		}
+	}
+out:
+	return minutes ? minutes * 60 : 60;
+}
+
+static void runjobs(void)
+{
+	time_t now = time(NULL);
+	struct tm tmstruct;
+	crontab_t mask, *t;
+
+	localtime_r(&now, &tmstruct);
+	cron_tm_to_mask(&mask, &tmstruct);
+
+	for (t = jobs; t != NULL; t = t->next) {
+		if (cron_should_run(t, &mask))
+			runjob(t);
+	}
+}
+
+static void sighandler(int signo)
+{
+	switch (signo) {
+	case SIGINT:
+	case SIGTERM:
+		run = 0;
+		break;
+	case SIGHUP:
+		rescan = 1;
+		break;
+	}
+}
+
+int main(void)
+{
+	struct timespec stime;
+	struct sigaction act;
+	crontab_t *t;
+	int timeout;
+	pid_t pid;
+
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = sighandler;
+	sigaction(SIGINT, &act, NULL);
+	sigaction(SIGTERM, &act, NULL);
+	sigaction(SIGHUP, &act, NULL);
+
+	while (run) {
+		if (rescan == 1) {
+			cleanup_config();
+			read_config();
+			timeout = 60;
+			rescan = 0;
+		} else {
+			runjobs();
+			timeout = calc_timeout();
+		}
+
+		stime.tv_sec = timeout;
+		stime.tv_nsec = 0;
+
+		while (nanosleep(&stime, &stime) != 0 && run && !rescan) {
+			if (errno != EINTR) {
+				perror("nanosleep");
+				break;
+			}
+		}
+
+		while ((pid = waitpid(-1, NULL, WNOHANG)) != -1) {
+			for (t = jobs; t != NULL; t = t->next) {
+				if (t->pid == pid) {
+					t->pid = -1;
+					break;
+				}
+			}
+		}
+	}
+
+	return EXIT_SUCCESS;
+}

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);
+}

lib/Makemodule.am

@@ -4,7 +4,7 @@ libinit_a_SOURCES = lib/util/delsvc.c lib/util/svcmap.c lib/util/enum_by_name.c
 libinit_a_SOURCES += lib/util/rdsvc.c lib/util/svcscan.c lib/util/mksock.c
 libinit_a_SOURCES += lib/util/del_svc_list.c lib/util/svc_tsort.c
 libinit_a_SOURCES += lib/util/opensock.c lib/util/enum_to_name.c
-libinit_a_SOURCES += lib/util/print_version.c $(HEADRS)
+libinit_a_SOURCES += lib/util/print_version.c lib/util/argv_exec.c $(HEADRS)
 libinit_a_CPPFLAGS = $(AM_CPPFLAGS)
 libinit_a_CFLAGS = $(AM_CFLAGS)
 

lib/cron/rdcron.c

@@ -490,6 +490,11 @@ crontab_t *rdcron(int dirfd, const char *filename)
 	}
 
 	cron->pid = -1;
+	cron->minute = 0xFFFFFFFFFFFFFFFFUL;
+	cron->hour = 0xFFFFFFFF;
+	cron->dayofmonth = 0xFFFFFFFF;
+	cron->month = 0xFFFF;
+	cron->dayofweek = 0xFF;
 
 	rdline_init(&rd, fd, filename, 0, NULL);
 	ret = rdcfg(cron, &rd, cron_params, ARRAY_SIZE(cron_params), 0);

lib/include/service.h

@@ -20,6 +20,8 @@
 
 #include <sys/types.h>
 
+#include "util.h"
+
 enum {
 	/*
 		Start the service in the background and continue with
@@ -123,5 +125,9 @@ const char *svc_target_to_string(int target);
 
 int svc_target_from_string(const char *target);
 
+int setup_tty(const char *tty, bool truncate);
+
+NORETURN void argv_exec(exec_t *e);
+
 #endif /* SERVICE_H */
 

lib/util/argv_exec.c

@@ -0,0 +1,67 @@
+/* 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 "service.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+int setup_tty(const char *tty, bool truncate)
+{
+	int fd;
+
+	if (tty == NULL)
+		return 0;
+
+	fd = open(tty, O_RDWR);
+	if (fd < 0) {
+		perror(tty);
+		return -1;
+	}
+
+	if (truncate)
+		ftruncate(fd, 0);
+
+	close(STDIN_FILENO);
+	close(STDOUT_FILENO);
+	close(STDERR_FILENO);
+
+	setsid();
+
+	dup2(fd, STDIN_FILENO);
+	dup2(fd, STDOUT_FILENO);
+	dup2(fd, STDERR_FILENO);
+	close(fd);
+	return 0;
+}
+
+void argv_exec(exec_t *e)
+{
+	char **argv = alloca(e->argc + 1), *ptr;
+	int i;
+
+	for (ptr = e->args, i = 0; i < e->argc; ++i, ptr += strlen(ptr) + 1)
+		argv[i] = ptr;
+
+	argv[i] = NULL;
+	execvp(argv[0], argv);
+	perror(argv[0]);
+	exit(EXIT_FAILURE);
+}

services/Makemodule.am

@@ -18,9 +18,13 @@ if USYSLOGD
 init_DATA += services/klogd
 endif
 
+if GCROND
+init_DATA += services/gcrond
+endif
+
 EXTRA_DIST += services/sysinit services/vfs services/agetty services/hostname
 EXTRA_DIST += services/hwclock services/loopback services/klogd
 EXTRA_DIST += services/sync services/sysctl services/tmpfs
 EXTRA_DIST += services/dhcpcd services/dhcpcdmaster services/unbound
 EXTRA_DIST += services/usyslogd services/dnsmasq services/network
-EXTRA_DIST += services/consolefont
+EXTRA_DIST += services/consolefont services/gcrond

services/gcrond

@@ -0,0 +1,5 @@
+description start gcron daemon
+exec gcrond
+type respawn
+target boot
+after network