Add exception handler to logger, exit on errors

Add exception handler mechanism to logger and use that to exit cleanly
when sslsplit fails to write to a log file or fails to open a log file.

Issue:		#113
Reported by:	Matthias Kadenbach

log.c

@@ -51,6 +51,19 @@
  */
 
 
+/*
+ * Common code for all logs.
+ */
+static proxy_ctx_t *proxy_ctx = NULL;
+
+static void
+log_exceptcb(void)
+{
+	if (proxy_ctx) {
+		proxy_loopbreak(proxy_ctx);
+	}
+}
+
 /*
  * Error log.
  * Switchable between stderr and syslog.
@@ -937,7 +950,8 @@ log_preinit(opts_t *opts)
 			prepcb = log_content_file_prepcb;
 		}
 		if (!(content_log = logger_new(reopencb, opencb, closecb,
-		                               writecb, prepcb))) {
+		                               writecb, prepcb,
+		                               log_exceptcb))) {
 			log_content_file_fini();
 			goto out;
 		}
@@ -945,18 +959,21 @@ log_preinit(opts_t *opts)
 	if (opts->connectlog) {
 		if (log_connect_preinit(opts->connectlog) == -1)
 			goto out;
-		if (!(connect_log = logger_new(log_connect_reopencb, NULL, NULL,
-		                               log_connect_writecb, NULL))) {
+		if (!(connect_log = logger_new(log_connect_reopencb,
+		                               NULL, NULL,
+		                               log_connect_writecb, NULL,
+		                               log_exceptcb))) {
 			log_connect_fini();
 			goto out;
 		}
 	}
 	if (opts->certgendir) {
 		if (!(cert_log = logger_new(NULL, NULL, NULL, log_cert_writecb,
-		                            NULL)))
+		                            NULL, log_exceptcb)))
 			goto out;
 	}
-	if (!(err_log = logger_new(NULL, NULL, NULL, log_err_writecb, NULL)))
+	if (!(err_log = logger_new(NULL, NULL, NULL, log_err_writecb, NULL,
+	                           log_exceptcb)))
 		goto out;
 	return 0;
 
@@ -997,8 +1014,9 @@ log_preinit_undo(void)
  * Return -1 on errors, 0 otherwise.
  */
 int
-log_init(opts_t *opts, int clisock1, int clisock2)
+log_init(opts_t *opts, proxy_ctx_t *ctx, int clisock1, int clisock2)
 {
+	proxy_ctx = ctx;
 	if (err_log)
 		if (logger_start(err_log) == -1)
 			return -1;

log.h

@@ -29,6 +29,7 @@
 #define LOG_H
 
 #include "opts.h"
+#include "proxy.h"
 #include "logger.h"
 #include "attrib.h"
 
@@ -69,7 +70,7 @@ int log_cert_submit(const char *, X509 *) NONNULL(1,2) WUNRES;
 
 int log_preinit(opts_t *) NONNULL(1) WUNRES;
 void log_preinit_undo(void);
-int log_init(opts_t *, int, int) NONNULL(1) WUNRES;
+int log_init(opts_t *, proxy_ctx_t *, int, int) NONNULL(1,2) WUNRES;
 void log_fini(void);
 int log_reopen(void) WUNRES;
 

logger.c

@@ -49,6 +49,7 @@ struct logger {
 	logger_close_func_t close;
 	logger_prep_func_t prep;
 	logger_write_func_t write;
+	logger_except_func_t except;
 	thrqueue_t *queue;
 };
 
@@ -70,7 +71,7 @@ logger_clear(logger_t *logger)
 logger_t *
 logger_new(logger_reopen_func_t reopenfunc, logger_open_func_t openfunc,
            logger_close_func_t closefunc, logger_write_func_t writefunc,
-           logger_prep_func_t prepfunc)
+           logger_prep_func_t prepfunc, logger_except_func_t exceptfunc)
 {
 	logger_t *logger;
 
@@ -83,6 +84,7 @@ logger_new(logger_reopen_func_t reopenfunc, logger_open_func_t openfunc,
 	logger->close = closefunc;
 	logger->write = writefunc;
 	logger->prep = prepfunc;
+	logger->except = exceptfunc;
 	logger->queue = NULL;
 	return logger;
 }
@@ -186,16 +188,24 @@ logger_thread(void *arg)
 {
 	logger_t *logger = arg;
 	logbuf_t *lb;
+	int e = 0;
 
 	while ((lb = thrqueue_dequeue(logger->queue))) {
 		if (logbuf_ctl_isset(lb, LBFLAG_REOPEN)) {
-			logger->reopen();
+			if (logger->reopen() != 0)
+				e = 1;
 		} else if (logbuf_ctl_isset(lb, LBFLAG_OPEN)) {
-			logger->open(lb->fh);
+			if (logger->open(lb->fh) != 0)
+				e = 1;
 		} else if (logbuf_ctl_isset(lb, LBFLAG_CLOSE)) {
 			logger->close(lb->fh);
 		} else {
-			logbuf_write_free(lb, logger->write);
+			if (logbuf_write_free(lb, logger->write) < 0)
+				e = 1;
+		}
+
+		if (e && logger->except) {
+			logger->except();
 		}
 	}
 

logger.h

@@ -39,11 +39,13 @@ typedef int (*logger_open_func_t)(void *);
 typedef void (*logger_close_func_t)(void *);
 typedef ssize_t (*logger_write_func_t)(void *, const void *, size_t);
 typedef logbuf_t * (*logger_prep_func_t)(void *, unsigned long, logbuf_t *);
+typedef void (*logger_except_func_t)(void);
 typedef struct logger logger_t;
 
 logger_t * logger_new(logger_reopen_func_t, logger_open_func_t,
                       logger_close_func_t, logger_write_func_t,
-                      logger_prep_func_t) NONNULL(4) MALLOC;
+                      logger_prep_func_t, logger_except_func_t)
+                      NONNULL(4,6) MALLOC;
 void logger_free(logger_t *) NONNULL(1);
 int logger_start(logger_t *) NONNULL(1) WUNRES;
 void logger_leave(logger_t *) NONNULL(1);

main.c

@@ -950,7 +950,7 @@ main(int argc, char *argv[])
 	ssl_reinit();
 
 	/* Post-privdrop/chroot/detach initialization, thread spawning */
-	if (log_init(opts, clisock[1], clisock[2]) == -1) {
+	if (log_init(opts, proxy, clisock[1], clisock[2]) == -1) {
 		fprintf(stderr, "%s: failed to init log facility: %s\n",
 		                argv0, strerror(errno));
 		goto out_log_failed;

proxy.c

@@ -208,7 +208,7 @@ proxy_signal_cb(evutil_socket_t fd, UNUSED short what, void *arg)
 	case SIGQUIT:
 	case SIGINT:
 	case SIGHUP:
-		event_base_loopbreak(ctx->evbase);
+		proxy_loopbreak(ctx);
 		break;
 	case SIGUSR1:
 		if (log_reopen() == -1) {
@@ -393,6 +393,15 @@ proxy_run(proxy_ctx_t *ctx)
 	}
 }
 
+/*
+ * Break the loop of the proxy, causing the proxy_run to return.
+ */
+void
+proxy_loopbreak(proxy_ctx_t *ctx)
+{
+	event_base_loopbreak(ctx->evbase);
+}
+
 /*
  * Free the proxy data structures.
  */

proxy.h

@@ -35,6 +35,7 @@ typedef struct proxy_ctx proxy_ctx_t;
 
 proxy_ctx_t * proxy_new(opts_t *, int) NONNULL(1) MALLOC;
 void proxy_run(proxy_ctx_t *) NONNULL(1);
+void proxy_loopbreak(proxy_ctx_t *) NONNULL(1);
 void proxy_free(proxy_ctx_t *) NONNULL(1);
 
 #endif /* !PROXY_H */