Add some missing error handling

3 files changed, 119 insertions, 90 deletions

diff --git a/src/config.c b/src/config.c
index f18d975..8c63b4e 100644
--- a/src/config.c
+++ b/src/config.c
@@ -163,7 +163,8 @@ void fastd_read_peer_dir(fastd_context *ctx, fastd_config *conf, const char *dir
 
 		read_peer_dir(ctx, conf, conf->peer_dirs->str);
 
-		chdir(oldcwd);
+		if(chdir(oldcwd))
+			pr_error(ctx, "can't chdir to `%s': %s", oldcwd, strerror(errno));
 	}
 	else {
 		pr_error(ctx, "change from directory `%s' to `%s' failed: %s", oldcwd, dir, strerror(errno));
@@ -250,7 +251,8 @@ bool fastd_read_config(fastd_context *ctx, fastd_config *conf, const char *filen
 	fastd_config_pstate_delete(ps);
 	fastd_config_yylex_destroy(scanner);
 
-	chdir(oldcwd);
+	if(chdir(oldcwd))
+		pr_error(ctx, "can't chdir to `%s': %s", oldcwd, strerror(errno));
 
 	free(filename2);
 	free(oldcwd);
@@ -568,7 +570,9 @@ static void reconfigure_read_peer_dirs(fastd_context *ctx, fastd_config *new_con
 			pr_error(ctx, "change from directory `%s' to `%s' failed: %s", oldcwd, dir->str, strerror(errno));
 	}
 
-	chdir(oldcwd);
+	if (chdir(oldcwd))
+		pr_error(ctx, "can't chdir to `%s': %s", oldcwd, strerror(errno));
+
 	free(oldcwd);
 }
 
diff --git a/src/fastd.c b/src/fastd.c
index ca4edb8..b2cc196 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -191,22 +191,28 @@ static void on_up(fastd_context *ctx) {
 		return;
 
 	char *cwd = get_current_dir_name();
-	chdir(ctx->conf->on_up_dir);
 
-	setenv("INTERFACE", ctx->ifname, 1);
+	if (!chdir(ctx->conf->on_up_dir)) {
+		setenv("INTERFACE", ctx->ifname, 1);
 
-	char buf[6];
-	snprintf(buf, 6, "%u", ctx->conf->mtu);
-	setenv("MTU", buf, 1);
+		char buf[6];
+		snprintf(buf, 6, "%u", ctx->conf->mtu);
+		setenv("MTU", buf, 1);
 
-	int ret = system(ctx->conf->on_up);
+		int ret = system(ctx->conf->on_up);
 
-	if (WIFSIGNALED(ret))
-		pr_error(ctx, "on-up command exited with signal %i", WTERMSIG(ret));
-	else if(ret)
-		pr_warn(ctx, "on-up command exited with status %i", WEXITSTATUS(ret));
+		if (WIFSIGNALED(ret))
+			pr_error(ctx, "on-up command exited with signal %i", WTERMSIG(ret));
+		else if(ret)
+			pr_warn(ctx, "on-up command exited with status %i", WEXITSTATUS(ret));
+
+		if (chdir(cwd))
+			pr_error(ctx, "can't chdir to `%s': %s", cwd, strerror(errno));
+	}
+	else {
+		pr_error(ctx, "can't chdir to `%s': %s", ctx->conf->on_up_dir, strerror(errno));
+	}
 
-	chdir(cwd);
 	free(cwd);
 }
 
@@ -215,22 +221,28 @@ static void on_down(fastd_context *ctx) {
 		return;
 
 	char *cwd = get_current_dir_name();
-	chdir(ctx->conf->on_down_dir);
 
-	setenv("INTERFACE", ctx->ifname, 1);
+	if(!chdir(ctx->conf->on_down_dir)) {
+		setenv("INTERFACE", ctx->ifname, 1);
 
-	char buf[6];
-	snprintf(buf, 6, "%u", ctx->conf->mtu);
-	setenv("MTU", buf, 1);
+		char buf[6];
+		snprintf(buf, 6, "%u", ctx->conf->mtu);
+		setenv("MTU", buf, 1);
 
-	int ret = system(ctx->conf->on_down);
+		int ret = system(ctx->conf->on_down);
 
-	if (WIFSIGNALED(ret))
-		pr_error(ctx, "on-down command exited with signal %i", WTERMSIG(ret));
-	else if(ret)
-		pr_warn(ctx, "on-down command exited with status %i", WEXITSTATUS(ret));
+		if (WIFSIGNALED(ret))
+			pr_error(ctx, "on-down command exited with signal %i", WTERMSIG(ret));
+		else if(ret)
+			pr_warn(ctx, "on-down command exited with status %i", WEXITSTATUS(ret));
+
+		if (chdir(cwd))
+			pr_error(ctx, "can't chdir to `%s': %s", cwd, strerror(errno));
+	}
+	else {
+		pr_error(ctx, "can't chdir to `%s': %s", ctx->conf->on_down_dir, strerror(errno));
+	}
 
-	chdir(cwd);
 	free(cwd);
 }
 
@@ -306,7 +318,8 @@ static void handle_tasks(fastd_context *ctx) {
 					fastd_peer_eth_addr_add(ctx, task->peer, src_addr);
 			}
 
-			write(ctx->tunfd, task->handle_recv.buffer.data, task->handle_recv.buffer.len);
+			if (write(ctx->tunfd, task->handle_recv.buffer.data, task->handle_recv.buffer.len) < 0)
+				warn_errno(ctx, "write");
 
 			if (ctx->conf->mode == MODE_TAP && ctx->conf->peer_to_peer) {
 				const fastd_eth_addr *dest_addr = fastd_get_dest_address(ctx, task->handle_recv.buffer);
diff --git a/src/peer.c b/src/peer.c
index fd8577b..4c85db2 100644
--- a/src/peer.c
+++ b/src/peer.c
@@ -38,51 +38,57 @@ static void on_establish(fastd_context *ctx, fastd_peer *peer) {
 		return;
 
 	char *cwd = get_current_dir_name();
-	chdir(ctx->conf->on_establish_dir);
 
-	setenv("INTERFACE", ctx->ifname, 1);
+	if(!chdir(ctx->conf->on_establish_dir)) {
+		setenv("INTERFACE", ctx->ifname, 1);
 
-	char buf[INET6_ADDRSTRLEN];
-	snprintf(buf, sizeof(buf), "%u", ctx->conf->mtu);
-	setenv("MTU", buf, 1);
+		char buf[INET6_ADDRSTRLEN];
+		snprintf(buf, sizeof(buf), "%u", ctx->conf->mtu);
+		setenv("MTU", buf, 1);
 
-	if (peer->config && peer->config->name)
-		setenv("PEER_NAME", peer->config->name, 1);
-	else
-		unsetenv("PEER_NAME");
+		if (peer->config && peer->config->name)
+			setenv("PEER_NAME", peer->config->name, 1);
+		else
+			unsetenv("PEER_NAME");
 
-	switch(peer->address.sa.sa_family) {
-	case AF_INET:
-		inet_ntop(AF_INET, &peer->address.in.sin_addr, buf, sizeof(buf));
-		setenv("PEER_ADDRESS", buf, 1);
+		switch(peer->address.sa.sa_family) {
+		case AF_INET:
+			inet_ntop(AF_INET, &peer->address.in.sin_addr, buf, sizeof(buf));
+			setenv("PEER_ADDRESS", buf, 1);
 
-		snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in.sin_port));
-		setenv("PEER_PORT", buf, 1);
+			snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in.sin_port));
+			setenv("PEER_PORT", buf, 1);
 
-		break;
+			break;
 
-	case AF_INET6:
-		inet_ntop(AF_INET6, &peer->address.in6.sin6_addr, buf, sizeof(buf));
-		setenv("PEER_ADDRESS", buf, 1);
+		case AF_INET6:
+			inet_ntop(AF_INET6, &peer->address.in6.sin6_addr, buf, sizeof(buf));
+			setenv("PEER_ADDRESS", buf, 1);
 
-		snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in6.sin6_port));
-		setenv("PEER_PORT", buf, 1);
+			snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in6.sin6_port));
+			setenv("PEER_PORT", buf, 1);
 
-		break;
+			break;
 
-	default:
-		unsetenv("PEER_ADDRESS");
-		unsetenv("PEER_PORT");
-	}
+		default:
+			unsetenv("PEER_ADDRESS");
+			unsetenv("PEER_PORT");
+		}
 
-	int ret = system(ctx->conf->on_establish);
+		int ret = system(ctx->conf->on_establish);
 
-	if (WIFSIGNALED(ret))
-		pr_error(ctx, "on-establish command exited with signal %i", WTERMSIG(ret));
-	else if(ret)
-		pr_warn(ctx, "on-establish command exited with status %i", WEXITSTATUS(ret));
+		if (WIFSIGNALED(ret))
+			pr_error(ctx, "on-establish command exited with signal %i", WTERMSIG(ret));
+		else if(ret)
+			pr_warn(ctx, "on-establish command exited with status %i", WEXITSTATUS(ret));
+
+		if(chdir(cwd))
+			pr_error(ctx, "can't chdir to `%s': %s", cwd, strerror(errno));
+	}
+	else {
+		pr_error(ctx, "can't chdir to `%s': %s", ctx->conf->on_establish_dir, strerror(errno));
+	}
 
-	chdir(cwd);
 	free(cwd);
 }
 
@@ -91,51 +97,57 @@ static void on_disestablish(fastd_context *ctx, fastd_peer *peer) {
 		return;
 
 	char *cwd = get_current_dir_name();
-	chdir(ctx->conf->on_disestablish_dir);
 
-	setenv("INTERFACE", ctx->ifname, 1);
+	if(!chdir(ctx->conf->on_disestablish_dir)) {
+		setenv("INTERFACE", ctx->ifname, 1);
 
-	char buf[INET6_ADDRSTRLEN];
-	snprintf(buf, sizeof(buf), "%u", ctx->conf->mtu);
-	setenv("MTU", buf, 1);
+		char buf[INET6_ADDRSTRLEN];
+		snprintf(buf, sizeof(buf), "%u", ctx->conf->mtu);
+		setenv("MTU", buf, 1);
 
-	if (peer->config && peer->config->name)
-		setenv("PEER_NAME", peer->config->name, 1);
-	else
-		unsetenv("PEER_NAME");
+		if (peer->config && peer->config->name)
+			setenv("PEER_NAME", peer->config->name, 1);
+		else
+			unsetenv("PEER_NAME");
 
-	switch(peer->address.sa.sa_family) {
-	case AF_INET:
-		inet_ntop(AF_INET, &peer->address.in.sin_addr, buf, sizeof(buf));
-		setenv("PEER_ADDRESS", buf, 1);
+		switch(peer->address.sa.sa_family) {
+		case AF_INET:
+			inet_ntop(AF_INET, &peer->address.in.sin_addr, buf, sizeof(buf));
+			setenv("PEER_ADDRESS", buf, 1);
 
-		snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in.sin_port));
-		setenv("PEER_PORT", buf, 1);
+			snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in.sin_port));
+			setenv("PEER_PORT", buf, 1);
 
-		break;
+			break;
 
-	case AF_INET6:
-		inet_ntop(AF_INET6, &peer->address.in6.sin6_addr, buf, sizeof(buf));
-		setenv("PEER_ADDRESS", buf, 1);
+		case AF_INET6:
+			inet_ntop(AF_INET6, &peer->address.in6.sin6_addr, buf, sizeof(buf));
+			setenv("PEER_ADDRESS", buf, 1);
 
-		snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in6.sin6_port));
-		setenv("PEER_PORT", buf, 1);
+			snprintf(buf, sizeof(buf), "%u", ntohs(peer->address.in6.sin6_port));
+			setenv("PEER_PORT", buf, 1);
 
-		break;
+			break;
 
-	default:
-		unsetenv("PEER_ADDRESS");
-		unsetenv("PEER_PORT");
-	}
+		default:
+			unsetenv("PEER_ADDRESS");
+			unsetenv("PEER_PORT");
+		}
 
-	int ret = system(ctx->conf->on_disestablish);
+		int ret = system(ctx->conf->on_disestablish);
 
-	if (WIFSIGNALED(ret))
-		pr_error(ctx, "on-disestablish command exited with signal %i", WTERMSIG(ret));
-	else if(ret)
-		pr_warn(ctx, "on-disestablish command exited with status %i", WEXITSTATUS(ret));
+		if (WIFSIGNALED(ret))
+			pr_error(ctx, "on-disestablish command exited with signal %i", WTERMSIG(ret));
+		else if(ret)
+			pr_warn(ctx, "on-disestablish command exited with status %i", WEXITSTATUS(ret));
+
+		if(chdir(cwd))
+			pr_error(ctx, "can't chdir to `%s': %s", cwd, strerror(errno));
+	}
+	else {
+		pr_error(ctx, "can't chdir to `%s': %s", ctx->conf->on_disestablish_dir, strerror(errno));
+	}
 
-	chdir(cwd);
 	free(cwd);
 }