rework the daemon to do fork+exec

It uses the 'common' proc.c from various OpenBSD-daemons.

gmid grew organically bit by bit and it was also the first place where I
tried to implement privsep.  It wasn't done very well, in fact the
parent process (that retains root privileges) just fork()s a generation
of servers, all sharing *exactly* the same address space.  No good!

Now, we fork() and re-exec() ourselves, so that each process has a fresh
address space.

Some features (require client ca for example) are temporarly disabled,
will be fixed in subsequent commits.  The "ge" program is also
temporarly disabled as it needs tweaks to do privsep too.

1 files changed, 62 insertions, 53 deletions

diff --git a/logger.c b/logger.c
index c509ddb..08aa19e 100644
--- a/logger.c
+++ b/logger.c
@@ -32,21 +32,22 @@
 
 #include "logger.h"
 #include "log.h"
+#include "proc.h"
 
-static struct event imsgev;
+#ifndef nitems
+#define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
+#endif
 
 static FILE *log;
 
-static void	handle_imsg_quit(struct imsgbuf*, struct imsg*, size_t);
-static void	handle_imsg_log(struct imsgbuf*, struct imsg*, size_t);
-static void	handle_imsg_log_type(struct imsgbuf*, struct imsg*, size_t);
-static void	handle_dispatch_imsg(int, short, void*);
+static void logger_init(struct privsep *, struct privsep_proc *, void *);
+static void logger_shutdown(void);
+static int logger_dispatch_parent(int, struct privsep_proc *, struct imsg *);
+static int logger_dispatch_server(int, struct privsep_proc *, struct imsg *);
 
-static imsg_handlerfn *handlers[] = {
-	[IMSG_QUIT] = handle_imsg_quit,
-	[IMSG_LOG] = handle_imsg_log,
-	[IMSG_LOG_REQUEST] = handle_imsg_log,
-	[IMSG_LOG_TYPE] = handle_imsg_log_type,
+static struct privsep_proc procs[] = {
+	{ "parent",	PROC_PARENT,	logger_dispatch_parent },
+	{ "server",	PROC_SERVER,	logger_dispatch_server },
 };
 
 void
@@ -99,74 +100,82 @@ log_request(struct client *c, char *meta, size_t l)
 	if (ec == -1)
 		err(1, "asprintf");
 
-	imsg_compose(&logibuf, IMSG_LOG_REQUEST, 0, 0, -1, fmted, ec + 1);
-	imsg_flush(&logibuf);
+	proc_compose(conf.ps, PROC_LOGGER, IMSG_LOG_REQUEST,
+	    fmted, ec + 1);
 
 	free(fmted);
 }
 
 
 
-static void
-handle_imsg_quit(struct imsgbuf *ibuf, struct imsg *imsg, size_t datalen)
+void
+logger(struct privsep *ps, struct privsep_proc *p)
 {
-	event_loopbreak();
+	proc_run(ps, p, procs, nitems(procs), logger_init, NULL);
 }
 
 static void
-handle_imsg_log(struct imsgbuf *ibuf, struct imsg *imsg, size_t datalen)
+logger_init(struct privsep *ps, struct privsep_proc *p, void *arg)
 {
-	char	*msg;
-
-	msg = imsg->data;
-	msg[datalen-1] = '\0';
-
-	if (log != NULL)
-		fprintf(log, "%s\n", msg);
-	else
-		syslog(LOG_DAEMON | LOG_NOTICE, "%s", msg);
+	p->p_shutdown = logger_shutdown;
+	log = stderr;
+	sandbox_logger_process();
 }
 
 static void
-handle_imsg_log_type(struct imsgbuf *ibuf, struct imsg *imsg, size_t datalen)
+logger_shutdown(void)
 {
-	if (log != NULL && log != stderr) {
+	closelog();
+	if (log && log != stderr) {
 		fflush(log);
 		fclose(log);
 	}
-	log = NULL;
+}
+
+static int
+logger_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
+{
+	switch (imsg->hdr.type) {
+	case IMSG_LOG_TYPE:
+		if (log != NULL && log != stderr) {
+			fflush(log);
+			fclose(log);
+		}
+		log = NULL;
 
-	if (imsg->fd != -1) {
-		if ((log = fdopen(imsg->fd, "a")) == NULL) {
-			syslog(LOG_DAEMON | LOG_ERR, "fdopen: %s",
-			    strerror(errno));
-			exit(1);
+		if (imsg->fd != -1) {
+			if ((log = fdopen(imsg->fd, "a")) == NULL)
+				fatal("fdopen");
 		}
+		break;
+	default:
+		return -1;
 	}
-}
 
-static void
-handle_dispatch_imsg(int fd, short ev, void *d)
-{
-	struct imsgbuf *ibuf = d;
-	dispatch_imsg(ibuf, handlers, sizeof(handlers));
+	return 0;
 }
 
-int
-logger_main(int fd, struct imsgbuf *ibuf)
+static int
+logger_dispatch_server(int fd, struct privsep_proc *p, struct imsg *imsg)
 {
-	log = stderr;
-
-	event_init();
-
-	event_set(&imsgev, fd, EV_READ | EV_PERSIST, &handle_dispatch_imsg, ibuf);
-	event_add(&imsgev, NULL);
-
-	sandbox_logger_process();
-
-	event_dispatch();
-
-	closelog();
+	char *msg;
+	size_t datalen;
+
+	switch (imsg->hdr.type) {
+	case IMSG_LOG_REQUEST:
+		msg = imsg->data;
+		datalen = IMSG_DATA_SIZE(imsg);
+		if (datalen == 0)
+			fatal("got invalid IMSG_LOG_REQUEST");
+		msg[datalen - 1] = '\0';
+		if (log != NULL)
+			fprintf(log, "%s\n", msg);
+		else
+			syslog(LOG_DAEMON | LOG_NOTICE, "%s", msg);
+		break;
+	default:
+		return -1;
+	}
 
 	return 0;
 }