Add helper library for cron configuration

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

9 files changed, 882 insertions, 88 deletions

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 817a2a5..7620e63 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -9,11 +9,16 @@ libinit_a_CPPFLAGS = $(AM_CPPFLAGS)
 libinit_a_CFLAGS = $(AM_CFLAGS)
 
 libcfg_a_SOURCES = lib/libcfg/rdline.c lib/libcfg/unescape.c
-libcfg_a_SOURCES += lib/libcfg/splitkv.c
+libcfg_a_SOURCES += lib/libcfg/splitkv.c lib/libcfg/rdcfg.c
 libcfg_a_SOURCES += lib/libcfg/pack_argv.c lib/include/libcfg.h
 libcfg_a_CPPFLAGS = $(AM_CPPFLAGS)
 libcfg_a_CFLAGS = $(AM_CFLAGS)
 
-EXTRA_DIST += $(HEADRS) lib/include/libcfg.h
+libcron_a_SOURCES = lib/cron/rdcron.c lib/cron/delcron.c lib/cron/crontab.c
+libcron_a_SOURCES += lib/cron/cronscan.c lib/include/crontab.h
+libcron_a_CPPFLAGS = $(AM_CPPFLAGS)
+libcron_a_CFLAGS = $(AM_CFLAGS)
 
-noinst_LIBRARIES += libinit.a libcfg.a
+EXTRA_DIST += $(HEADRS) lib/include/libcfg.h lib/include/crontab.h
+
+noinst_LIBRARIES += libinit.a libcfg.a libcron.a
diff --git a/lib/cron/cronscan.c b/lib/cron/cronscan.c
new file mode 100644
index 0000000..e28fb03
--- /dev/null
+++ b/lib/cron/cronscan.c
@@ -0,0 +1,77 @@
+/* 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 <sys/types.h>
+#include <sys/stat.h>
+#include <stddef.h>
+#include <dirent.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#include "crontab.h"
+
+int cronscan(const char *directory, crontab_t **list)
+{
+	struct dirent *ent;
+	int dfd, ret = 0;
+	crontab_t *cron;
+	DIR *dir;
+
+	dir = opendir(directory);
+	if (dir == NULL) {
+		perror(directory);
+		return -1;
+	}
+
+	dfd = dirfd(dir);
+	if (dfd < 0) {
+		perror(directory);
+		closedir(dir);
+		return -1;
+	}
+
+	for (;;) {
+		errno = 0;
+		ent = readdir(dir);
+
+		if (ent == NULL) {
+			if (errno != 0) {
+				perror(directory);
+				ret = -1;
+			}
+			break;
+		}
+
+		if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
+			continue;
+
+		cron = rdcron(dfd, ent->d_name);
+		if (cron == NULL) {
+			ret = -1;
+			continue;
+		}
+
+		cron->next = *list;
+		*list = cron;
+	}
+
+	closedir(dir);
+	return ret;
+}
diff --git a/lib/cron/crontab.c b/lib/cron/crontab.c
new file mode 100644
index 0000000..f761ec0
--- /dev/null
+++ b/lib/cron/crontab.c
@@ -0,0 +1,50 @@
+/* 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 <string.h>
+
+#include "crontab.h"
+
+void cron_tm_to_mask(crontab_t *out, struct tm *t)
+{
+	memset(out, 0, sizeof(*out));
+	out->minute     = 1UL << ((unsigned long)t->tm_min);
+	out->hour       = 1 << t->tm_hour;
+	out->dayofmonth = 1 << (t->tm_mday - 1);
+	out->month      = 1 << t->tm_mon;
+	out->dayofweek  = 1 << t->tm_wday;
+}
+
+bool cron_should_run(const crontab_t *t, const crontab_t *mask)
+{
+	if ((t->minute & mask->minute) == 0)
+		return false;
+
+	if ((t->hour & mask->hour) == 0)
+		return false;
+
+	if ((t->dayofmonth & mask->dayofmonth) == 0)
+		return false;
+
+	if ((t->month & mask->month) == 0)
+		return false;
+
+	if ((t->dayofweek & mask->dayofweek) == 0)
+		return false;
+
+	return true;
+}
diff --git a/lib/cron/delcron.c b/lib/cron/delcron.c
new file mode 100644
index 0000000..1877db1
--- /dev/null
+++ b/lib/cron/delcron.c
@@ -0,0 +1,38 @@
+/* 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 <stdlib.h>
+
+#include "crontab.h"
+
+void delcron(crontab_t *cron)
+{
+	exec_t *e;
+
+	if (cron == NULL)
+		return;
+
+	while (cron->exec != NULL) {
+		e = cron->exec;
+		cron->exec = e->next;
+
+		free(e);
+	}
+
+	free(cron->ctty);
+	free(cron);
+}
diff --git a/lib/cron/rdcron.c b/lib/cron/rdcron.c
new file mode 100644
index 0000000..42936ce
--- /dev/null
+++ b/lib/cron/rdcron.c
@@ -0,0 +1,503 @@
+/* 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 <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <pwd.h>
+#include <grp.h>
+
+#include "crontab.h"
+#include "libcfg.h"
+#include "util.h"
+
+
+static const enum_map_t weekday[] = {
+	{ "MON", 1 },
+	{ "TUE", 2 },
+	{ "WED", 3 },
+	{ "THU", 4 },
+	{ "FRI", 5 },
+	{ "SAT", 6 },
+	{ "SUN", 0 },
+};
+
+static const enum_map_t month[] = {
+	{ "JAN", 1 },
+	{ "FEB", 2 },
+	{ "MAR", 3 },
+	{ "APR", 4 },
+	{ "MAY", 5 },
+	{ "JUN", 6 },
+	{ "JUL", 7 },
+	{ "AUG", 8 },
+	{ "SEP", 9 },
+	{ "OCT", 10 },
+	{ "NOV", 11 },
+	{ "DEC", 12 },
+};
+
+static const struct {
+	const char *macro;
+	crontab_t tab;
+} intervals[] = {
+	{
+		.macro = "yearly",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0x01,
+			.dayofmonth = 0x01,
+			.month = 0x01,
+			.dayofweek = 0xFF
+		},
+	}, {
+		.macro = "annually",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0x01,
+			.dayofmonth = 0x01,
+			.month = 0x01,
+			.dayofweek = 0xFF
+		},
+	}, {
+		.macro = "monthly",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0x01,
+			.dayofmonth = 0x01,
+			.month = 0xFFFF,
+			.dayofweek = 0xFF
+		},
+	}, {
+		.macro = "weekly",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0x01,
+			.dayofmonth = 0xFFFFFFFF,
+			.month = 0xFFFF,
+			.dayofweek = 0x01
+		},
+	}, {
+		.macro = "daily",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0x01,
+			.dayofmonth = 0xFFFFFFFF,
+			.month = 0xFFFF,
+			.dayofweek = 0xFF
+		},
+	}, {
+		.macro = "hourly",
+		.tab = {
+			.minute = 0x01,
+			.hour = 0xFFFFFFFF,
+			.dayofmonth = 0xFFFFFFFF,
+			.month = 0xFFFF,
+			.dayofweek = 0xFF
+		},
+	},
+};
+
+/*****************************************************************************/
+
+static int try_unescape(char *arg, rdline_t *rd)
+{
+	if (unescape(arg)) {
+		fprintf(stderr, "%s: %zu: malformed string constant\n",
+			rd->filename, rd->lineno);
+		return -1;
+	}
+	return 0;
+}
+
+static char *try_strdup(const char *str, rdline_t *rd)
+{
+	char *out = strdup(str);
+
+	if (out == NULL) {
+		fprintf(stderr, "%s: %zu: out of memory\n",
+			rd->filename, rd->lineno);
+	}
+	return out;
+}
+
+static char *readnum(char *line, int *out, int minval, int maxval,
+		     const enum_map_t *mnemonic, rdline_t *rd)
+{
+	int i, temp, value = 0;
+	const enum_map_t *ev;
+
+	if (!isdigit(*line)) {
+		if (!mnemonic)
+			goto fail_mn;
+
+		for (i = 0; isalnum(line[i]); ++i)
+			;
+		if (i == 0)
+			goto fail_mn;
+
+		temp = line[i];
+		line[i] = '\0';
+		ev = enum_by_name(mnemonic, line);
+		if (!ev) {
+			fprintf(stderr, "%s: %zu: unexpected '%s'",
+				rd->filename, rd->lineno, line);
+		}
+		line[i] = temp;
+		if (!ev)
+			return NULL;
+		*out = ev->value;
+		return line + i;
+	}
+
+	while (isdigit(*line)) {
+		i = ((*(line++)) - '0');
+		if (value > (maxval - i) / 10)
+			goto fail_of;
+		value = value * 10 + i;
+	}
+
+	if (value < minval)
+		goto fail_uf;
+
+	*out = value;
+	return line;
+fail_of:
+	fprintf(stderr, "%s: %zu: value exceeds maximum (%d > %d)\n",
+		rd->filename, rd->lineno, value, maxval);
+	return NULL;
+fail_uf:
+	fprintf(stderr, "%s: %zu: value too small (%d < %d)\n",
+		rd->filename, rd->lineno, value, minval);
+	return NULL;
+fail_mn:
+	fprintf(stderr, "%s: %zu: expected numeric value",
+		rd->filename, rd->lineno);
+	return NULL;
+}
+
+static char *readfield(char *line, uint64_t *out, int minval, int maxval,
+		       const enum_map_t *mnemonic, rdline_t *rd)
+{
+	int value, endvalue, step;
+	uint64_t v = 0;
+next:
+	if (*line == '*') {
+		++line;
+		value = minval;
+		endvalue = maxval;
+	} else {
+		line = readnum(line, &value, minval, maxval, mnemonic, rd);
+		if (!line)
+			goto fail;
+
+		if (*line == '-') {
+			line = readnum(line + 1, &endvalue, minval, maxval,
+				       mnemonic, rd);
+			if (!line)
+				goto fail;
+		} else {
+			endvalue = value;
+		}
+	}
+
+	if (endvalue < value)
+		goto fail;
+
+	if (*line == '/') {
+		line = readnum(line + 1, &step, 1, maxval + 1, NULL, rd);
+		if (!line)
+			goto fail;
+	} else {
+		step = 1;
+	}
+
+	while (value <= endvalue) {
+		v |= 1UL << (unsigned long)(value - minval);
+		value += step;
+	}
+
+	if (*line == ',' || *line == ' ') {
+		++line;
+		goto next;
+	}
+
+	if (*line != '\0')
+		goto fail;
+
+	*out = v;
+	return line;
+fail:
+	fprintf(stderr, "%s: %zu: invalid time range expression\n",
+		rd->filename, rd->lineno);
+	return NULL;
+}
+
+/*****************************************************************************/
+
+static int cron_exec(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	exec_t *e, *end;
+	(void)flags;
+
+	e = calloc(1, sizeof(*e) + strlen(arg) + 1);
+	if (e == NULL) {
+		fprintf(stderr, "%s: %zu: out of memory\n",
+			rd->filename, rd->lineno);
+		return -1;
+	}
+
+	strcpy(e->args, arg);
+
+	e->argc = pack_argv(e->args);
+	if (e->argc < 0) {
+		fprintf(stderr, "%s: %zu: malformed string constant\n",
+			rd->filename, rd->lineno);
+		return -1;
+	}
+
+	if (cron->exec == NULL) {
+		cron->exec = e;
+	} else {
+		for (end = cron->exec; end->next != NULL; end = end->next)
+			;
+		end->next = e;
+	}
+	return 0;
+}
+
+static int cron_hour(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	uint64_t value;
+	(void)flags;
+
+	if (!readfield(arg, &value, 0, 23, NULL, rd))
+		return -1;
+
+	cron->hour = value;
+	return 0;
+}
+
+static int cron_minute(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	uint64_t value;
+	(void)flags;
+
+	if (!readfield(arg, &value, 0, 59, NULL, rd))
+		return -1;
+
+	cron->minute = value;
+	return 0;
+}
+
+static int cron_dayofmonth(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	uint64_t value;
+	(void)flags;
+
+	if (!readfield(arg, &value, 1, 31, NULL, rd))
+		return -1;
+
+	cron->dayofmonth = value;
+	return 0;
+}
+
+static int cron_dayofweek(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	uint64_t value;
+	(void)flags;
+
+	if (!readfield(arg, &value, 0, 6, weekday, rd))
+		return -1;
+
+	cron->dayofweek = value;
+	return 0;
+}
+
+static int cron_month(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	uint64_t value;
+	(void)flags;
+
+	if (!readfield(arg, &value, 1, 12, month, rd))
+		return -1;
+
+	cron->month = value;
+	return 0;
+}
+
+static int cron_interval(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	size_t i;
+	(void)flags;
+
+	for (i = 0; i < ARRAY_SIZE(intervals); ++i) {
+		if (!strcmp(intervals[i].macro, arg)) {
+			cron->minute = intervals[i].tab.minute;
+			cron->hour = intervals[i].tab.hour;
+			cron->dayofmonth = intervals[i].tab.dayofmonth;
+			cron->month = intervals[i].tab.month;
+			cron->dayofweek = intervals[i].tab.dayofweek;
+			return 0;
+		}
+	}
+
+	fprintf(stderr, "%s: %zu: unknown interval '%s'\n",
+		rd->filename, rd->lineno, arg);
+	return -1;
+}
+
+static int cron_user(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	struct passwd *pwd;
+	bool isnumeric;
+	char *ptr;
+	int value;
+	(void)flags;
+
+	for (ptr = arg; isdigit(*ptr); ++ptr)
+		;
+
+	isnumeric = (*ptr == '\0');
+	pwd = getpwnam(arg);
+
+	if (pwd == NULL && !isnumeric) {
+		fprintf(stderr, "%s: %zu: unknown user '%s'\n",
+			rd->filename, rd->lineno, arg);
+		return -1;
+	}
+
+	if (pwd != NULL) {
+		cron->uid = pwd->pw_uid;
+	} else {
+		if (readnum(arg, &value, 0, INT_MAX, NULL, rd))
+			return -1;
+		cron->uid = value;
+	}
+	return 0;
+}
+
+static int cron_group(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	struct group *group;
+	bool isnumeric;
+	char *ptr;
+	int value;
+	(void)flags;
+
+	for (ptr = arg; isdigit(*ptr); ++ptr)
+		;
+
+	isnumeric = (*ptr == '\0');
+	group = getgrnam(arg);
+
+	if (group == NULL && !isnumeric) {
+		fprintf(stderr, "%s: %zu: unknown group '%s'\n",
+			rd->filename, rd->lineno, arg);
+		return -1;
+	}
+
+	if (group != NULL) {
+		cron->gid = group->gr_gid;
+	} else {
+		if (readnum(arg, &value, 0, INT_MAX, NULL, rd))
+			return -1;
+		cron->gid = value;
+	}
+	return 0;
+}
+
+static int cron_tty(void *user, char *arg, rdline_t *rd, int flags)
+{
+	crontab_t *cron = user;
+	(void)flags;
+
+	if (strncmp(arg, "truncate", 8) == 0 && isspace(arg[8])) {
+		cron->tty_truncate = 1;
+		arg += 8;
+		while (isspace(*arg))
+			++arg;
+	}
+
+	if (try_unescape(arg, rd))
+		return -1;
+
+	cron->ctty = try_strdup(arg, rd);
+	return cron->ctty == NULL ? -1 : 0;
+}
+
+
+
+static const cfg_param_t cron_params[] = {
+	{ "hour", 0, cron_hour },
+	{ "minute", 0, cron_minute },
+	{ "dayofmonth", 0, cron_dayofmonth },
+	{ "dayofweek", 0, cron_dayofweek },
+	{ "month", 0, cron_month },
+	{ "interval", 0, cron_interval },
+	{ "user", 0, cron_user },
+	{ "group", 0, cron_group },
+	{ "tty", 0, cron_tty },
+	{ "exec", 1, cron_exec },
+};
+
+crontab_t *rdcron(int dirfd, const char *filename)
+{
+	crontab_t *cron;
+	rdline_t rd;
+	int fd, ret;
+
+	fd = openat(dirfd, filename, O_RDONLY);
+	if (fd < 0) {
+		perror(filename);
+		return NULL;
+	}
+
+	cron = calloc(1, sizeof(*cron));
+	if (cron == NULL) {
+		fputs("out of memory\n", stderr);
+		goto out;
+	}
+
+	cron->pid = -1;
+
+	rdline_init(&rd, fd, filename, 0, NULL);
+	ret = rdcfg(cron, &rd, cron_params, ARRAY_SIZE(cron_params), 0);
+	if (ret) {
+		delcron(cron);
+		cron = NULL;
+	}
+out:
+	close(fd);
+	return cron;
+}
diff --git a/lib/include/crontab.h b/lib/include/crontab.h
new file mode 100644
index 0000000..408d276
--- /dev/null
+++ b/lib/include/crontab.h
@@ -0,0 +1,56 @@
+/* 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 CRONTAB_H
+#define CRONTAB_H
+
+#include <sys/types.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <time.h>
+
+#include "service.h"
+
+typedef struct crontab_t {
+	struct crontab_t *next;
+	exec_t *exec;
+	char *ctty;
+
+	uid_t uid;
+	gid_t gid;
+	pid_t pid;
+
+	uint64_t minute;
+	uint32_t hour;
+	uint32_t dayofmonth;
+	uint16_t month;
+	uint8_t dayofweek;
+
+	unsigned int tty_truncate : 1;
+} crontab_t;
+
+crontab_t *rdcron(int dirfd, const char *filename);
+
+void delcron(crontab_t *cron);
+
+int cronscan(const char *directory, crontab_t **list);
+
+void cron_tm_to_mask(crontab_t *out, struct tm *t);
+
+bool cron_should_run(const crontab_t *t, const crontab_t *mask);
+
+#endif /* CRONTAB_H */
diff --git a/lib/include/libcfg.h b/lib/include/libcfg.h
index 83b9213..8096f1b 100644
--- a/lib/include/libcfg.h
+++ b/lib/include/libcfg.h
@@ -19,6 +19,7 @@
 #define LIBCONFIG_H
 
 #include <stdbool.h>
+#include <stddef.h>
 
 typedef struct {
 	int fd;			/* input file descriptor */
@@ -38,6 +39,20 @@ typedef struct {
 	bool comment;		/* inside a comment */
 } rdline_t;
 
+typedef struct {
+	/* keyword to map the callback to */
+	const char *key;
+
+	/*
+		If set, allow grouping repetitions of the keyword in a single
+		multi line '{' ... '}' block. The callback is called for each
+		line.
+	 */
+	unsigned int allow_block : 1;
+
+	int (*handle)(void *obj, char *arg, rdline_t *rd, int flags);
+} cfg_param_t;
+
 /*
 	Initialize the config line scanner.
 
@@ -104,4 +119,13 @@ int pack_argv(char *str);
  */
 int splitkv(rdline_t *rd, char **k, char **v);
 
+/*
+	Parse a configuration file containing '<keyword> [arguments...]' lines.
+	The cfgobj and flags are passed to the callback in the params array.
+
+	Returns zero on success.
+ */
+int rdcfg(void *cfgobj, rdline_t *rd, const cfg_param_t *params, size_t count,
+	  int flags);
+
 #endif /* LIBCONFIG_H */
diff --git a/lib/libcfg/rdcfg.c b/lib/libcfg/rdcfg.c
new file mode 100644
index 0000000..71a994f
--- /dev/null
+++ b/lib/libcfg/rdcfg.c
@@ -0,0 +1,83 @@
+/* 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 "libcfg.h"
+
+#include <string.h>
+#include <stdio.h>
+
+static const cfg_param_t *find_param(rdline_t *rd, const char *name,
+				     const cfg_param_t *params, size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; ++i) {
+		if (!strcmp(params[i].key, name))
+			return params + i;
+	}
+
+	fprintf(stderr, "%s: %zu: unknown keyword '%s'\n",
+		rd->filename, rd->lineno, name);
+	return NULL;
+}
+
+int rdcfg(void *cfgobj, rdline_t *rd, const cfg_param_t *params, size_t count,
+	  int flags)
+{
+	const cfg_param_t *p;
+	char *key, *value;
+	int ret;
+
+	while ((ret = rdline(rd)) == 0) {
+		if (splitkv(rd, &key, &value))
+			return -1;
+
+		p = find_param(rd, key, params, count);
+		if (p == NULL)
+			return -1;
+
+		if (p->allow_block && *value == '{') {
+			for (++value; *value == ' '; ++value)
+				;
+
+			if (*value != '\0') {
+				ret = p->handle(cfgobj, value, rd, flags);
+				if (ret)
+					return -1;
+			}
+
+			while ((ret = rdline(rd)) == 0) {
+				if (strcmp(rd->buffer, "}") == 0)
+					break;
+				if (p->handle(cfgobj, rd->buffer, rd, flags))
+					return -1;
+			}
+
+			if (ret < 0)
+				return -1;
+			if (ret > 0)
+				goto fail_bra;
+		} else if (p->handle(cfgobj, value, rd, flags)) {
+			return -1;
+		}
+	}
+
+	return ret < 0 ? -1 : 0;
+fail_bra:
+	fprintf(stderr, "%s: missing '}' before end-of-file\n", rd->filename);
+	return -1;
+}
diff --git a/lib/util/rdsvc.c b/lib/util/rdsvc.c
index 3e146a2..747d753 100644
--- a/lib/util/rdsvc.c
+++ b/lib/util/rdsvc.c
@@ -60,16 +60,24 @@ static int try_pack_argv(char *str, rdline_t *rd)
 	return count;
 }
 
-static int svc_desc(service_t *svc, char *arg, rdline_t *rd)
+static int svc_desc(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
+	(void)flags;
+
 	if (try_unescape(arg, rd))
 		return -1;
 	svc->desc = try_strdup(arg, rd);
 	return svc->desc == NULL ? -1 : 0;
 }
 
-static int svc_tty(service_t *svc, char *arg, rdline_t *rd)
+static int svc_tty(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
+
+	if (flags & RDSVC_NO_CTTY)
+		return 0;
+
 	if (strncmp(arg, "truncate", 8) == 0 && isspace(arg[8])) {
 		svc->flags |= SVC_FLAG_TRUNCATE_OUT;
 		arg += 8;
@@ -84,10 +92,14 @@ static int svc_tty(service_t *svc, char *arg, rdline_t *rd)
 	return svc->ctty == NULL ? -1 : 0;
 }
 
-static int svc_exec(service_t *svc, char *arg, rdline_t *rd)
+static int svc_exec(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
 	exec_t *e, *end;
 
+	if (flags & RDSVC_NO_EXEC)
+		return 0;
+
 	e = calloc(1, sizeof(*e) + strlen(arg) + 1);
 	if (e == NULL) {
 		fprintf(stderr, "%s: %zu: out of memory\n",
@@ -111,8 +123,13 @@ static int svc_exec(service_t *svc, char *arg, rdline_t *rd)
 	return 0;
 }
 
-static int svc_before(service_t *svc, char *arg, rdline_t *rd)
+static int svc_before(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
+
+	if (flags & RDSVC_NO_DEPS)
+		return 0;
+
 	if (svc->before != NULL) {
 		fprintf(stderr, "%s: %zu: 'before' dependencies respecified\n",
 			rd->filename, rd->lineno);
@@ -127,8 +144,13 @@ static int svc_before(service_t *svc, char *arg, rdline_t *rd)
 	return (svc->num_before < 0) ? -1 : 0;
 }
 
-static int svc_after(service_t *svc, char *arg, rdline_t *rd)
+static int svc_after(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
+
+	if (flags & RDSVC_NO_DEPS)
+		return 0;
+
 	if (svc->after != NULL) {
 		fprintf(stderr, "%s: %zu: 'after' dependencies respecified\n",
 			rd->filename, rd->lineno);
@@ -143,9 +165,11 @@ static int svc_after(service_t *svc, char *arg, rdline_t *rd)
 	return (svc->num_after < 0) ? -1 : 0;
 }
 
-static int svc_type(service_t *svc, char *arg, rdline_t *rd)
+static int svc_type(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
 	int count = try_pack_argv(arg, rd);
+	(void)flags;
 
 	if (count < 1)
 		return -1;
@@ -189,9 +213,11 @@ fail_limit:
 	return -1;
 }
 
-static int svc_target(service_t *svc, char *arg, rdline_t *rd)
+static int svc_target(void *user, char *arg, rdline_t *rd, int flags)
 {
+	service_t *svc = user;
 	int target;
+	(void)flags;
 
 	if (try_unescape(arg, rd))
 		return -1;
@@ -208,48 +234,23 @@ static int svc_target(service_t *svc, char *arg, rdline_t *rd)
 	return 0;
 }
 
-static const struct svc_param {
-	const char *key;
-
-	unsigned int allow_block : 1;
-
-	int flags;
-
-	int (*handle)(service_t *svc, char *arg, rdline_t *rd);
-} svc_params[] = {
-	{ "description", 0, 0, svc_desc },
-	{ "exec", 1, RDSVC_NO_EXEC, svc_exec },
-	{ "type", 0, 0, svc_type },
-	{ "target", 0, 0, svc_target },
-	{ "tty", 0, RDSVC_NO_CTTY, svc_tty },
-	{ "before", 0, RDSVC_NO_DEPS, svc_before },
-	{ "after", 0, RDSVC_NO_DEPS, svc_after },
+static const cfg_param_t svc_params[] = {
+	{ "description", 0, svc_desc },
+	{ "exec", 1, svc_exec },
+	{ "type", 0, svc_type },
+	{ "target", 0, svc_target },
+	{ "tty", 0, svc_tty },
+	{ "before", 0, svc_before },
+	{ "after", 0, svc_after },
 };
 
-static const struct svc_param *find_param(rdline_t *rd, const char *name)
-{
-	size_t i;
-
-	for (i = 0; i < ARRAY_SIZE(svc_params); ++i) {
-		if (!strcmp(svc_params[i].key, name))
-			return svc_params + i;
-	}
-
-	fprintf(stderr, "%s: %zu: unknown keyword '%s'\n",
-		rd->filename, rd->lineno, name);
-	return NULL;
-}
-
-
 service_t *rdsvc(int dirfd, const char *filename, int flags)
 {
-	const struct svc_param *p;
 	const char *arg, *args[1];
 	service_t *svc = NULL;
-	char *key, *value;
 	size_t argc, nlen;
 	rdline_t rd;
-	int fd, ret;
+	int fd;
 
 	fd = openat(dirfd, filename, O_RDONLY);
 	if (fd < 0) {
@@ -281,54 +282,11 @@ service_t *rdsvc(int dirfd, const char *filename, int flags)
 
 	memcpy(svc->name, filename, nlen);
 
-	while ((ret = rdline(&rd)) == 0) {
-		if (splitkv(&rd, &key, &value))
-			goto fail;
-
-		p = find_param(&rd, key);
-		if (p == NULL)
-			goto fail;
-
-		if (p->allow_block && *value == '{') {
-			for (++value; *value == ' '; ++value)
-				;
-
-			if (!(flags & p->flags)) {
-				if (*value != '\0' &&
-				    p->handle(svc, value, &rd)) {
-					goto fail;
-				}
-			}
-
-			while ((ret = rdline(&rd)) == 0) {
-				if (strcmp(rd.buffer, "}") == 0)
-					break;
-				if (flags & p->flags)
-					continue;
-				if (p->handle(svc, rd.buffer, &rd))
-					goto fail;
-			}
-
-			if (ret < 0)
-				goto fail;
-			if (ret > 0)
-				goto fail_bra;
-		} else {
-			if (flags & p->flags)
-				continue;
-			if (p->handle(svc, value, &rd))
-				goto fail;
-		}
-	}
-
-	if (ret < 0)
+	if (rdcfg(svc, &rd, svc_params, ARRAY_SIZE(svc_params), flags))
 		goto fail;
 
 	close(fd);
 	return svc;
-fail_bra:
-	fprintf(stderr, "%s: missing '}' before end-of-file\n", filename);
-	goto fail;
 fail_oom:
 	fputs("out of memory\n", stderr);
 fail: