src/confd: improved coverage of ietf-system

- Call external programs safely with run()
 - Use augeas to update /etc/hostname and /etc/hosts
 - Add support for generating /etc/chrony.conf
 - Update license copyright due to significant contrib.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/confd/LICENSE

@@ -1,4 +1,5 @@
 Copyright (c) 2020 Denis Kalashnikov
+Copyright (c) 2023 The KernelKit Authors
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

src/confd/src/Makefile.am

@@ -3,7 +3,7 @@ AM_CPPFLAGS             = -DYANG_PATH_=\"$(YANGDIR)/\"
 plugindir               = $(srpdplugindir)
 plugin_LTLIBRARIES      = confd-plugin.la
 
-confd_plugin_la_CFLAGS  = $(sysrepo_CFLAGS) $(CFLAGS)
-confd_plugin_la_LIBADD  = $(sysrepo_LIBS)   $(CFLAGS)
+confd_plugin_la_CFLAGS  = $(augeas_CFLAGS) $(sysrepo_CFLAGS) $(CFLAGS)
+confd_plugin_la_LIBADD  = $(augeas_LIBS)   $(sysrepo_LIBS)   $(CFLAGS)
 confd_plugin_la_LDFLAGS = -module -avoid-version -shared
 confd_plugin_la_SOURCES = ietf-system.c

src/confd/src/ietf-system.c

@@ -1,5 +1,6 @@
-/* Sysrepo plugin of ietf-system@2014-08-06.yang module */
+/* SPDX-License-Identifier: BSD-3-Clause */
 
+#include <augeas.h>
 #include <stdio.h>
 #include <syslog.h>
 #include <stdlib.h>
@@ -15,15 +16,72 @@
 
 #include <libyang/libyang.h>
 #include <sysrepo.h>
+#include <sysrepo/values.h>
+#include <sysrepo/xpath.h>
 
 #define CLOCK_PATH_    "/ietf-system:system-state/clock"
 #define PLATFORM_PATH_ "/ietf-system:system-state/platform"
 
+
+#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
+
 #define DEBUG(frmt, ...)
 //#define DEBUG(frmt, ...) syslog(LOG_DEBUG, "%s: "frmt, __func__, ##__VA_ARGS__)
 #define ERROR(frmt, ...) syslog(LOG_ERR, "%s: " frmt, __func__, ##__VA_ARGS__)
 #define ERRNO(frmt, ...) syslog(LOG_ERR, "%s: " frmt ": %s", __func__, ##__VA_ARGS__, strerror(errno))
 
+static augeas *aug;
+
+
+/**
+ * Like system(), but takes a formatted string as argument.
+ * @param fmt  printf style format list to command to run
+ *
+ * This system() wrapper greatly simplifies operations that usually
+ * consist of composing a command from parts into a dynamic buffer
+ * before calling it.  The return value from system() is also parsed,
+ * checking for proper exit and signals.
+ *
+ * @returns If the command exits normally, the return code of the command
+ * is returned.  Otherwise, if the command is signalled, the return code
+ * is -1 and @a errno is set to @c EINTR.
+ */
+static int run(const char *fmt, ...)
+{
+	va_list ap;
+	char *cmd;
+	int len;
+	int rc;
+
+	va_start(ap, fmt);
+	len = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+
+	cmd = alloca(++len);
+	if (!cmd) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	va_start(ap, fmt);
+	vsnprintf(cmd, len, fmt, ap);
+	va_end(ap);
+
+	rc = system(cmd);
+	if (rc == -1)
+		return -1;
+
+	if (WIFEXITED(rc)) {
+		errno = 0;
+		rc = WEXITSTATUS(rc);
+	} else if (WIFSIGNALED(rc)) {
+		errno = EINTR;
+		rc = -1;
+	}
+
+	return rc;
+}
+
 /* Return seconds since boot */
 static long get_uptime(void)
 {
@@ -143,29 +201,26 @@ static int platform_cb(sr_session_ctx_t *session, uint32_t sub_id, const char *m
 	return SR_ERR_OK;
 }
 
-static int exec_rpc_cb(sr_session_ctx_t *session, uint32_t sub_id, const char *path,
-		       const sr_val_t *input, const size_t input_cnt,
-		       sr_event_t event, unsigned request_id,
-		       sr_val_t **output, size_t *output_cnt,
-		       void *priv)
+static int rpc_exec(sr_session_ctx_t *session, uint32_t sub_id, const char *path,
+		    const sr_val_t *input, const size_t input_cnt,
+		    sr_event_t event, unsigned request_id,
+		    sr_val_t **output, size_t *output_cnt,
+		    void *priv)
 {
-	int rc;
-
 	DEBUG("path: %s", path);
 
-	rc = system(priv);
-	if (WIFSIGNALED(rc) || (WIFEXITED(rc) && WEXITSTATUS(rc)))
+	if (run(priv))
 		return SR_ERR_INTERNAL;
 
 	return SR_ERR_OK;
 }
 
 /* '/ietf-system:set-current-date-time' */
-static int set_datetime_rpc_cb(sr_session_ctx_t *session, uint32_t sub_id,
-			       const char *path, const sr_val_t *input,
-			       const size_t input_cnt, sr_event_t event,
-			       unsigned request_id, sr_val_t **output,
-			       size_t *output_cnt, void *priv)
+static int rpc_set_datetime(sr_session_ctx_t *session, uint32_t sub_id,
+			    const char *path, const sr_val_t *input,
+			    const size_t input_cnt, sr_event_t event,
+			    unsigned request_id, sr_val_t **output,
+			    size_t *output_cnt, void *priv)
 {
 	struct timeval tv;
 	struct tm tm;
@@ -201,51 +256,287 @@ static int set_datetime_rpc_cb(sr_session_ctx_t *session, uint32_t sub_id,
 	return SR_ERR_OK;
 }
 
-int hostname_change_cb(sr_session_ctx_t *session, uint32_t sub_id, const char *module,
-		       const char *xpath, sr_event_t event,
-		       unsigned request_id, void *priv)
+static int sys_reload_services(void)
 {
-	sr_val_t *old_val, *new_val, *val;
-	sr_change_iter_t *iter;
-	sr_change_oper_t op;
+	return run("initctl -nbq touch sysklogd lldpd");
+}
+
+static void print_val(sr_val_t *val)
+{
+	char *str;
+
+	if (sr_print_val_mem(&str, val))
+		return;
+	ERROR("%s", str);
+	free(str);
+}
+
+int sr_get_bool(sr_session_ctx_t *session, const char *fmt, ...)
+{
+	sr_val_t *val = NULL;
+	char *xpath;
+	va_list ap;
+	int rc = 0;
+	int len;
+
+	va_start(ap, fmt);
+	len = vsnprintf(NULL, 0, fmt, ap) + 1;
+	va_end(ap);
+
+	xpath = alloca(len);
+	if (!xpath)
+		goto fail;
+
+	va_start(ap, fmt);
+	vsnprintf(xpath, len, fmt, ap);
+	va_end(ap);
+
+	if (sr_get_item(session, xpath, 0, &val))
+		goto fail;
+	if (!val || val->type != SR_BOOL_T)
+		goto fail;
+
+	rc = val->data.bool_val;
+fail:
+	if (val)
+		sr_free_val(val);
+	return rc;
+}
+
+char *sr_get_str(sr_session_ctx_t *session, const char *fmt, ...)
+{
+	char *str = NULL;
+	sr_val_t *val;
+	char *xpath;
+	va_list ap;
+	int len;
+
+	va_start(ap, fmt);
+	len = vsnprintf(NULL, 0, fmt, ap) + 1;
+	va_end(ap);
+
+	xpath = alloca(len);
+	if (!xpath)
+		return NULL;
+
+	va_start(ap, fmt);
+	vsnprintf(xpath, len, fmt, ap);
+	va_end(ap);
+
+	if (sr_get_item(session, xpath, 0, &val)) {
+		ERROR("Failed reading string value from xpath %s", xpath);
+		goto fail;
+	}
+	if (!val || val->type != SR_STRING_T)
+		goto fail;
+
+	str = strdup(val->data.string_val);
+fail:
+	if (val)
+		sr_free_val(val);
+	return str;
+}
+
+#define CHRONY_CONF "/etc/chrony.conf"
+#define CHRONY_PREV CHRONY_CONF "-"
+#define CHRONY_NEXT CHRONY_CONF "+"
+
+static int change_ntp(sr_session_ctx_t *session, uint32_t sub_id, const char *module,
+	const char *xpath, sr_event_t event, unsigned request_id, void *priv)
+{
+	const char *fn = CHRONY_NEXT;
+	int valid = -1;
+	sr_data_t *sdt;
+	sr_val_t *val;
+	size_t cnt;
+	FILE *fp;
 	int rc;
 
-	if (event != SR_EV_ENABLED && event != SR_EV_DONE)
+	switch (event) {
+	case SR_EV_ENABLED:	/* first time, on register. */
+	case SR_EV_CHANGE:	/* regular change (copy cand running) */
+		/* Generate next config */
+		break;
+
+	case SR_EV_ABORT:	/* User abort, or other plugin failed */
+		remove(CHRONY_NEXT);
 		return SR_ERR_OK;
 
-	rc = sr_get_changes_iter(session, "//.", &iter);
-	if (rc) {
-		ERROR("failed to get changes iter: %s", sr_strerror(rc));
-		return rc;
+	case SR_EV_DONE:
+		/* Check if passed validation in previous event */
+		if (access(CHRONY_NEXT, F_OK))
+			return SR_ERR_OK;
+
+		remove(CHRONY_PREV);
+		rename(CHRONY_CONF, CHRONY_PREV);
+		rename(CHRONY_NEXT, CHRONY_CONF);
+		if (!sr_get_bool(session, "/ietf-system:system/ntp/enabled")) {
+			run("initctl -nbq disable chronyd");
+			return SR_ERR_OK;
+		}
+		/*
+		 * If chrony is alrady enabled we tell Finit it's been
+		 * modified , so Finit restarts it, otherwise enable it.
+		 */
+		run("initctl -nbq touch chronyd");
+		run("initctl -nbq enable chronyd");
+		return SR_ERR_OK;
 	}
 
-	while (sr_get_change_next(session, iter, &op, &old_val, &new_val) == SR_ERR_OK) {
-		val = new_val ? new_val : old_val;
-		if (strcmp(val->xpath, "/ietf-system:system/hostname"))
-			goto free_vals;
+	if (rc = sr_get_items(session, "/ietf-system:system/ntp/server", 0, 0, &val, &cnt)) {
+		remove(CHRONY_NEXT);
+		return rc;
+	}
+	
+	fp = fopen(fn, "w");
+	if (!fp) {
+		ERROR("failed updating %s: %s", fn, strerror(errno));
+		sr_free_values(val, cnt);
+		return SR_ERR_SYS;
+	}
 
-		switch (op) {
-		case SR_OP_CREATED:
-		case SR_OP_MODIFIED:
-			if (sethostname(new_val->data.string_val,
-					strlen(new_val->data.string_val))) {
-				ERRNO("Failed to set hostname");
-				return SR_ERR_SYS;
+	for (size_t i = 0; i < cnt; i++) {
+		const char *xpath = val[i].xpath;
+		char *type, *ptr;
+		int server = 0;
+
+		/* 
+		 * Handle empty startup-config on SR_EV_ENABLED,
+		 * prevents subscribe failure due to false invalid.
+		 */
+		if (i == 0)
+			valid = 0;
+
+		/* Get /ietf-system:system/ntp/server[name='foo'] */
+		ptr = sr_get_str(session, "%s/udp/address", xpath);
+		if (ptr) {
+			type = sr_get_str(session, "%s/association-type", xpath);
+			fprintf(fp, "%s %s", type ?: "server", ptr);
+			server++;
+			if (type)
+				free(type);
+			free(ptr);
+
+			if (ptr = sr_get_str(session, "%s/udp/port", xpath)) {
+				fprintf(fp, " port %s", ptr);
+				free(ptr);
 			}
-
-			DEBUG("Set hostname to '%s'", new_val->data.string_val);
-			break;
 		}
 
-	free_vals:
-		sr_free_val(old_val);
-		sr_free_val(new_val);
+		if (server) {
+			if (sr_get_bool(session, "%s/iburst", xpath))
+				fprintf(fp, " iburst");
+			if (sr_get_bool(session, "%s/prefer", xpath))
+				fprintf(fp, " prefer");
+
+			fprintf(fp, "\n");
+			valid++;
+		}
+	}
+	sr_free_values(val, cnt);
+
+	fprintf(fp, "driftfile /var/lib/chrony/drift\n");
+	fprintf(fp, "makestep 1.0 3\n");
+	fprintf(fp, "maxupdateskew 100.0\n");
+	fprintf(fp, "dumpdir /var/lib/chrony\n");
+	fprintf(fp, "rtcfile /var/lib/chrony/rtc\n");
+	fclose(fp);
+
+	if (!valid) {
+		remove(fn);
+		return SR_ERR_VALIDATION_FAILED;
 	}
 
 	return SR_ERR_OK;
 }
 
-int sr_plugin_init_cb(sr_session_ctx_t *sess, void **priv)
+static int change_hostname(sr_session_ctx_t *session, uint32_t sub_id, const char *module,
+	const char *xpath, sr_event_t event, unsigned request_id, void *priv)
+{
+	const char *host, *nm, *tmp;
+	char **hosts, *current;
+	int err, i, nhosts;
+	int rc;
+
+	switch (event) {
+	case SR_EV_ENABLED:	/* first time, on register. */
+	case SR_EV_CHANGE:	/* regular change (copy cand running) */
+		/* Wait for DONE to activate changes */
+		return SR_ERR_OK;
+
+	case SR_EV_ABORT:	/* User abort, or other plugin failed */
+		return SR_ERR_OK;
+
+	case SR_EV_DONE:
+		/* Activate changes */
+		break;
+	}
+
+	nm = sr_get_str(session, xpath);
+	if (!nm) {
+		ERROR("No valid hostname in current session");
+		nm = "infix";	/* XXX: derive from global "options.h" */
+	}
+	ERROR("Got hostname %s", nm);
+
+	aug_get(aug, "etc/hostname/hostname", &tmp);
+	current = strdup(tmp);
+	ERROR("Current hostname %s", current);
+
+	err = sethostname(nm, strlen(nm));
+	err = err ? : aug_set(aug, "etc/hostname/hostname", nm);
+
+	nhosts = aug_match(aug, "etc/hosts/*/canonical", &hosts);
+	for (i = 0; i < nhosts; i++) {
+		aug_get(aug, hosts[i], &host);
+		if (!strcmp(host, current))
+			err = err ? : aug_set(aug, hosts[i], nm);
+		free(hosts[i]);
+	}
+	free(hosts);
+	free(current);
+
+	if (err) {
+		ERROR("Failed activating changes.");
+		return err;
+	}
+
+	ERROR("Reload hostname-dependent services ...");
+	err = err ? : aug_save(aug);
+	if (sys_reload_services())
+		return SR_ERR_SYS;
+
+	return SR_ERR_OK;
+}
+
+static int register_change(sr_session_ctx_t *session, const char *xpath,
+			   sr_module_change_cb cb, void *arg, sr_subscription_ctx_t **sub)
+{
+	int rc = sr_module_change_subscribe(session, "ietf-system", xpath, cb, arg, 0,
+					    SR_SUBSCR_DEFAULT | SR_SUBSCR_ENABLED, sub);
+	if (rc)
+		ERROR("failed subscribing to changes of %s: %s", xpath, sr_strerror(rc));
+	return rc;
+}
+
+static int register_rpc(sr_session_ctx_t *session, const char *xpath,
+			sr_rpc_cb cb, void *arg, sr_subscription_ctx_t **sub)
+{
+	int rc = sr_rpc_subscribe(session, xpath, cb, arg, 0, SR_SUBSCR_DEFAULT, sub);
+	if (rc)
+		ERROR("failed subscribing to %s rpc: %s", xpath, sr_strerror(rc));
+	return rc;
+}
+
+#define REGISTER_CHANGE(s,x,c,a,u) \
+	if (rc = register_change(s, x, c, a, u))\
+		goto err
+
+#define REGISTER_RPC(s,x,c,a,u) \
+	if (rc = register_rpc(s, x, c, a, u))	\
+		goto err
+
+int sr_plugin_init_cb(sr_session_ctx_t *session, void **priv)
 {
 	sr_subscription_ctx_t *sub = NULL;
 	sr_conn_ctx_t *conn;
@@ -257,44 +548,34 @@ int sr_plugin_init_cb(sr_session_ctx_t *sess, void **priv)
 	};
 	int rc;
 
-	openlog("sysrepo ietf-system plugin", LOG_USER, 0);
-	conn = sr_session_get_connection(sess);
+	aug = aug_init(NULL, "", 0);
+	if (!aug ||
+	    aug_load_file(aug, "/etc/hostname") ||
+	    aug_load_file(aug, "/etc/hosts")) {
+		ERROR("ietf-system: Augeas initialization failed");
+		goto err;
+	}
+
+	openlog("ietf-system", LOG_USER, 0);
+	conn = sr_session_get_connection(session);
 	sr_install_module(conn, YANG_PATH_"ietf-system@2014-08-06.yang", NULL, features);
 
-	rc = sr_oper_get_subscribe(sess, "ietf-system", CLOCK_PATH_,
+	rc = sr_oper_get_subscribe(session, "ietf-system", CLOCK_PATH_,
 				   clock_cb, NULL, SR_SUBSCR_DEFAULT, &sub);
 	if (rc != SR_ERR_OK)
 		goto err;
 
-	rc = sr_oper_get_subscribe(sess, "ietf-system", PLATFORM_PATH_,
+	rc = sr_oper_get_subscribe(session, "ietf-system", PLATFORM_PATH_,
 				   platform_cb, NULL, SR_SUBSCR_DEFAULT, &sub);
 	if (rc != SR_ERR_OK)
 		goto err;
 
-	rc = sr_rpc_subscribe(sess, "/ietf-system:system-restart",
-			      exec_rpc_cb, "reboot",
-			      0, SR_SUBSCR_DEFAULT, &sub);
-	if (rc != SR_ERR_OK)
-		goto err;
+	REGISTER_RPC(session, "/ietf-system:system-restart",  rpc_exec, "reboot", &sub);
+	REGISTER_RPC(session, "/ietf-system:system-shutdown", rpc_exec, "poweroff", &sub);
+	REGISTER_RPC(session, "/ietf-system:set-current-datetime", rpc_set_datetime, NULL, &sub);
 
-	rc = sr_rpc_subscribe(sess, "/ietf-system:system-shutdown",
-			      exec_rpc_cb, "poweroff", 0, SR_SUBSCR_DEFAULT, &sub);
-	if (rc != SR_ERR_OK)
-		goto err;
-
-	rc = sr_rpc_subscribe(sess, "/ietf-system:set-current-datetime",
-			      set_datetime_rpc_cb, NULL, 0, SR_SUBSCR_DEFAULT, &sub);
-	if (rc != SR_ERR_OK)
-		goto err;
-
-	rc = sr_module_change_subscribe(sess, "ietf-system", "/ietf-system:system/hostname",
-				        hostname_change_cb, NULL, 0,
-					SR_SUBSCR_DEFAULT | SR_SUBSCR_ENABLED, &sub);
-	if (rc != SR_ERR_OK) {
-		ERROR("failed to subscribe to changes of hostname: %s",
-		      sr_strerror(rc));
-		goto err;
-	}
+	REGISTER_CHANGE(session, "/ietf-system:system/hostname", change_hostname, NULL, &sub);
+	REGISTER_CHANGE(session, "/ietf-system:system/ntp", change_ntp, NULL, &sub);
 
 	*(sr_subscription_ctx_t **)priv = sub;
 	DEBUG("init ok");