Split configuration parser and utility library

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

1 files changed, 357 insertions, 0 deletions

diff --git a/lib/util/rdsvc.c b/lib/util/rdsvc.c
new file mode 100644
index 0000000..6a964f7
--- /dev/null
+++ b/lib/util/rdsvc.c
@@ -0,0 +1,357 @@
+/* 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 <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#include "service.h"
+#include "libcfg.h"
+#include "util.h"
+
+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 int try_pack_argv(char *str, rdline_t *rd)
+{
+	int count = pack_argv(str);
+	if (count < 0) {
+		fprintf(stderr, "%s: %zu: malformed string constant\n",
+			rd->filename, rd->lineno);
+	}
+	return count;
+}
+
+static int svc_desc(service_t *svc, char *arg, rdline_t *rd)
+{
+	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)
+{
+	if (try_unescape(arg, rd))
+		return -1;
+	svc->ctty = try_strdup(arg, rd);
+	return svc->ctty == NULL ? -1 : 0;
+}
+
+static int svc_exec(service_t *svc, char *arg, rdline_t *rd)
+{
+	exec_t *e, *end;
+
+	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 = try_pack_argv(e->args, rd);
+	if (e->argc < 0)
+		return -1;
+
+	if (svc->exec == NULL) {
+		svc->exec = e;
+	} else {
+		for (end = svc->exec; end->next != NULL; end = end->next)
+			;
+		end->next = e;
+	}
+	return 0;
+}
+
+static int svc_before(service_t *svc, char *arg, rdline_t *rd)
+{
+	if (svc->before != NULL) {
+		fprintf(stderr, "%s: %zu: 'before' dependencies respecified\n",
+			rd->filename, rd->lineno);
+		return -1;
+	}
+
+	svc->before = try_strdup(arg, rd);
+	if (svc->before == NULL)
+		return -1;
+
+	svc->num_before = try_pack_argv(svc->before, rd);
+	return (svc->num_before < 0) ? -1 : 0;
+}
+
+static int svc_after(service_t *svc, char *arg, rdline_t *rd)
+{
+	if (svc->after != NULL) {
+		fprintf(stderr, "%s: %zu: 'after' dependencies respecified\n",
+			rd->filename, rd->lineno);
+		return -1;
+	}
+
+	svc->after = try_strdup(arg, rd);
+	if (svc->after == NULL)
+		return -1;
+
+	svc->num_after = try_pack_argv(svc->after, rd);
+	return (svc->num_after < 0) ? -1 : 0;
+}
+
+static int svc_type(service_t *svc, char *arg, rdline_t *rd)
+{
+	int count = try_pack_argv(arg, rd);
+
+	if (count < 1)
+		return -1;
+
+	svc->type = svc_type_from_string(arg);
+
+	if (svc->type == -1) {
+		fprintf(stderr, "%s: %zu: unknown service type '%s'\n",
+			rd->filename, rd->lineno, arg);
+		return -1;
+	}
+
+	if (count > 1) {
+		arg += strlen(arg) + 1;
+
+		switch (svc->type) {
+		case SVC_RESPAWN:
+			if (strcmp(arg, "limit") != 0)
+				goto fail_limit;
+			arg += strlen(arg) + 1;
+
+			if (count > 3)
+				goto fail_args;
+			if (!isdigit(*arg))
+				goto fail_limit;
+			svc->rspwn_limit = atoi(arg);
+			break;
+		default:
+			goto fail_args;
+		}
+	}
+
+	return 0;
+fail_args:
+	fprintf(stderr, "%s: %zu: unexpected extra arguments\n",
+		rd->filename, rd->lineno);
+	return -1;
+fail_limit:
+	fprintf(stderr, "%s: %zu: expected 'limit <value>' after 'respawn'\n",
+		rd->filename, rd->lineno);
+	return -1;
+}
+
+static int svc_target(service_t *svc, char *arg, rdline_t *rd)
+{
+	int target;
+
+	if (try_unescape(arg, rd))
+		return -1;
+
+	target = svc_target_from_string(arg);
+
+	if (target == -1) {
+		fprintf(stderr, "%s: %zu: unknown service target '%s'\n",
+			rd->filename, rd->lineno, arg);
+		return -1;
+	}
+
+	svc->target = target;
+	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 int splitkv(rdline_t *rd, char **k, char **v)
+{
+	char *key = rd->buffer, *value = rd->buffer;
+
+	while (*value != ' ' && *value != '\0') {
+		if (!isalpha(*value)) {
+			fprintf(stderr,
+				"%s: %zu: unexpected '%c' in keyword\n",
+				rd->filename, rd->lineno, *value);
+			return -1;
+		}
+		++value;
+	}
+
+	if (*value != ' ') {
+		fprintf(stderr, "%s: %zu: expected argument after '%s'\n",
+			rd->filename, rd->lineno, key);
+		return -1;
+	}
+
+	*(value++) = '\0';
+
+	*k = key;
+	*v = value;
+	return 0;
+}
+
+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;
+
+	fd = openat(dirfd, filename, O_RDONLY);
+	if (fd < 0) {
+		perror(filename);
+		return NULL;
+	}
+
+	arg = strchr(filename, '@');
+	if (arg != NULL) {
+		args[0] = arg + 1;
+		argc = 1;
+	} else {
+		argc = 0;
+	}
+
+	rdline_init(&rd, fd, filename, argc, args);
+
+	nlen = (arg != NULL) ? (size_t)(arg - filename) : strlen(filename);
+
+	svc = calloc(1, sizeof(*svc) + nlen + 1);
+	if (svc == NULL)
+		goto fail_oom;
+
+	if (!(flags & RDSVC_NO_FNAME)) {
+		svc->fname = strdup(filename);
+		if (svc->fname == NULL)
+			goto fail_oom;
+	}
+
+	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)
+		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:
+	delsvc(svc);
+	close(fd);
+	return NULL;
+}