conf: generate runtime .conf files in the block format

Finit's own generated services -- watchdogd, keventd, runparts, and
the dbus plugin -- still went through conf_save_service() as legacy
one-liners, so `initctl show keventd` taught the old format on a
system otherwise converted to the new one.

conf_save_service() now takes the block title and a printf-style body
and writes the file itself:

    # Generated by finit:conf_save_service()
    service keventd {
            description = "Finit kernel event daemon"
            runlevel    = "S12345789"
            notify      = "none"
            cgroup init {}
            command     = "/libexec/finit/keventd"
    }

vfprintf() into the file also removes the fixed-size staging buffers
in the callers, where a long dbus pidfile path could truncate inside
a quoted string and take the whole generated file with it.

Semantics preserved: watch-only pid:! maps to pidfile without
pidfile-create, the watchdog keeps its watchdog:finit identity, and
log:console becomes log { file = "/dev/console" }.

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

plugins/dbus.c

@@ -100,7 +100,7 @@ static void setup(void *arg)
 {
 	char *group = DBUS_DAEMONGROUP;
 	char *user = DBUS_DAEMONUSER;
-	char line[256];
+	char pid[300];
 	char *pidfn;
 	mode_t prev;
 	char *cmd;
@@ -151,15 +151,19 @@ static void setup(void *arg)
 	 * Register service with Finit
 	 * Note: dbus drops privs after starting up.
 	 */
+	pid[0] = 0;
 	if (pidfn) {
-		snprintf(line, sizeof(line), "[S123456789] cgroup.system notify:none name:dbus pid:!%s %s %s -- %s",
-			 pidfn, cmd, DBUS_ARGS, DBUS_DESC);
+		snprintf(pid, sizeof(pid), "\tpidfile     = \"%s\"\n", pidfn);
 		free(pidfn);
-	} else
-		snprintf(line, sizeof(line), "[S123456789] cgroup.system notify:none name:dbus %s %s -- %s",
-			 cmd, DBUS_ARGS, DBUS_DESC);
-
-	conf_save_service(SVC_TYPE_SERVICE, line, "dbus.conf");
+	}
+	conf_save_service(SVC_TYPE_SERVICE, "dbus", "dbus.conf",
+			  "\tdescription = \"" DBUS_DESC "\"\n"
+			  "\trunlevel    = \"S123456789\"\n"
+			  "\tnotify      = \"none\"\n"
+			  "\tcgroup system {}\n"
+			  "%s"
+			  "\tcommand     = \"%s " DBUS_ARGS "\"\n",
+			  pid, cmd);
 	free(cmd);
 }
 

src/conf.c

@@ -43,6 +43,7 @@
 
 #include "config.h"		/* Generated by configure script */
 
+#include <stdarg.h>
 #include <string.h>
 #include <sys/inotify.h>
 #include <sys/resource.h>
@@ -664,11 +665,14 @@ done:
 }
 
 /*
- * Called by plugins and similar that dynamically generate system services
+ * Called by plugins and similar that dynamically generate system
+ * services.  @body holds the block contents, one indented line per
+ * setting.
  */
-void conf_save_service(int type, char *cfg, char *file)
+void conf_save_service(int type, const char *name, char *file, const char *fmt, ...)
 {
 	char fn[256];
+	va_list ap;
 	svc_t foo;
 	FILE *fp;
 
@@ -684,7 +688,11 @@ void conf_save_service(int type, char *cfg, char *file)
 
 	foo.type = type;
 	fprintf(fp, "# Generated by finit:%s()\n", __func__);
-	fprintf(fp, "%s %s\n", svc_typestr(&foo), cfg);
+	fprintf(fp, "%s %s {\n", svc_typestr(&foo), name);
+	va_start(ap, fmt);
+	vfprintf(fp, fmt, ap);
+	va_end(ap);
+	fprintf(fp, "}\n");
 	fclose(fp);
 }
 
@@ -2520,16 +2528,24 @@ int conf_init(uev_ctx_t *ctx)
 	 */
 #ifdef WDT_DEVNODE
 	if (whichp(FINIT_EXECPATH_ "/watchdogd") && fexist(WDT_DEVNODE)) {
-		conf_save_service(SVC_TYPE_SERVICE, "[S0123456789] cgroup.init notify:none name:watchdog :finit "
-				  FINIT_EXECPATH_ "/watchdogd -- Finit watchdog daemon", "watchdogd.conf");
+		conf_save_service(SVC_TYPE_SERVICE, "watchdog:finit", "watchdogd.conf",
+				  "\tdescription = \"Finit watchdog daemon\"\n"
+				  "\trunlevel    = \"S0123456789\"\n"
+				  "\tnotify      = \"none\"\n"
+				  "\tcgroup init {}\n"
+				  "\tcommand     = \"" FINIT_EXECPATH_ "/watchdogd\"\n");
 	}
 #endif
 	/*
 	 * Start kernel event daemon as soon as possible, if enabled
 	 */
 	if (whichp(FINIT_EXECPATH_ "/keventd"))
-		conf_save_service(SVC_TYPE_SERVICE, "[S12345789] cgroup.init notify:none "
-				  FINIT_EXECPATH_ "/keventd -- Finit kernel event daemon", "keventd.conf");
+		conf_save_service(SVC_TYPE_SERVICE, "keventd", "keventd.conf",
+				  "\tdescription = \"Finit kernel event daemon\"\n"
+				  "\trunlevel    = \"S12345789\"\n"
+				  "\tnotify      = \"none\"\n"
+				  "\tcgroup init {}\n"
+				  "\tcommand     = \"" FINIT_EXECPATH_ "/keventd\"\n");
 
 	dbg("Allow plugins to register early runlevel 1 run/task/services ...");
 	plugin_run_hooks(HOOK_SVC_PLUGIN);
@@ -2552,7 +2568,6 @@ int conf_init(uev_ctx_t *ctx)
 	 * Background startup scripts in the runparts directory, if any.
 	 */
 	if (runparts && fisdir(runparts) && !rescue) {
-		char conf[sizeof(_PATH_RUNPARTS) + strlen(runparts) + 100];
 		char args[10] = { 0 };
 
 		if (debug)
@@ -2562,10 +2577,14 @@ int conf_init(uev_ctx_t *ctx)
 		if (runparts_sysv)
 			strlcat(args, "-s ", sizeof(args));
 
-		snprintf(conf, sizeof(conf), "[S] <int/bootstrap> notify:none log:console %s %s %s"
-			 " -- Calling runparts %s in the background",
-			 _PATH_RUNPARTS, args, runparts, runparts);
-		conf_save_service(SVC_TYPE_TASK, conf, "runparts.conf");
+		conf_save_service(SVC_TYPE_TASK, "runparts", "runparts.conf",
+				  "\tdescription = \"Calling runparts %s in the background\"\n"
+				  "\trunlevel    = \"S\"\n"
+				  "\tconditions  = { \"int/bootstrap\" }\n"
+				  "\tnotify      = \"none\"\n"
+				  "\tlog { file = \"/dev/console\" }\n"
+				  "\tcommand     = \"%s %s%s\"\n",
+				  runparts, _PATH_RUNPARTS, args, runparts);
 	}
 
 	return 0;

src/conf.h

@@ -71,7 +71,8 @@ int   conf_monitor         (void);
 
 void  conf_saverc          (void);
 void  conf_save_exec_order (svc_t *svc, char *cmdline, int result);
-void  conf_save_service    (int type, char *cfg, char *file);
+void  conf_save_service    (int type, const char *name, char *file, const char *fmt, ...)
+                           __attribute__ ((format (printf, 4, 5)));
 void  conf_parse_cmdline   (int argc, char *argv[]);
 
 void  conf_reset_env       (void);