Handle EINTR in mod_rrdtool (fixes #604)

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2400 152afb58-edef-0310-8abb-c4023f1b3aa9

1 files changed, 46 insertions, 5 deletions

diff --git a/src/mod_rrdtool.c b/src/mod_rrdtool.c
index f405e259..67c44377 100644
--- a/src/mod_rrdtool.c
+++ b/src/mod_rrdtool.c
@@ -92,11 +92,11 @@ FREE_FUNC(mod_rrd_free) {
 }
 
 int mod_rrd_create_pipe(server *srv, plugin_data *p) {
+#ifdef HAVE_FORK
 	pid_t pid;
 
 	int to_rrdtool_fds[2];
 	int from_rrdtool_fds[2];
-#ifdef HAVE_FORK
 	if (pipe(to_rrdtool_fds)) {
 		log_error_write(srv, __FILE__, __LINE__, "ss",
 				"pipe failed: ", strerror(errno));
@@ -194,6 +194,47 @@ int mod_rrd_create_pipe(server *srv, plugin_data *p) {
 #endif
 }
 
+/* read/write wrappers to catch EINTR */
+
+/* write to blocking socket; blocks until all data is sent, write returns 0 or an error (apart from EINTR) occurs. */
+static ssize_t safe_write(int fd, const void *buf, size_t count) {
+	ssize_t res, sum = 0;
+
+	for (;;) {
+		res = write(fd, buf, count);
+		if (res >= 0) {
+			sum += res;
+			/* do not try again if res == 0 */
+			if (res == 0 || (size_t) res == count) return sum;
+			count -= res;
+			buf = (const char*) buf + res;
+			continue;
+		}
+		switch (errno) {
+		case EINTR:
+			continue;
+		default:
+			return -1;
+		}
+	}
+}
+
+/* this assumes we get enough data on a successful read */
+static ssize_t safe_read(int fd, void *buf, size_t count) {
+	ssize_t res;
+
+	for (;;) {
+		res = read(fd, buf, count);
+		if (res >= 0) return res;
+		switch (errno) {
+		case EINTR:
+			continue;
+		default:
+			return -1;
+		}
+	}
+}
+
 static int mod_rrdtool_create_rrd(server *srv, plugin_data *p, plugin_config *s) {
 	struct stat st;
 
@@ -229,7 +270,7 @@ static int mod_rrdtool_create_rrd(server *srv, plugin_data *p, plugin_config *s)
 			"RRA:MIN:0.5:24:775 "
 			"RRA:MIN:0.5:288:797\n"));
 
-		if (-1 == (r = write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
+		if (-1 == (r = safe_write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
 			log_error_write(srv, __FILE__, __LINE__, "ss",
 				"rrdtool-write: failed", strerror(errno));
 
@@ -237,7 +278,7 @@ static int mod_rrdtool_create_rrd(server *srv, plugin_data *p, plugin_config *s)
 		}
 
 		buffer_prepare_copy(p->resp, 4096);
-		if (-1 == (r = read(p->read_fd, p->resp->ptr, p->resp->size))) {
+		if (-1 == (r = safe_read(p->read_fd, p->resp->ptr, p->resp->size))) {
 			log_error_write(srv, __FILE__, __LINE__, "ss",
 				"rrdtool-read: failed", strerror(errno));
 
@@ -390,7 +431,7 @@ TRIGGER_FUNC(mod_rrd_trigger) {
 		buffer_append_long(p->cmd, s->requests);
 		buffer_append_string_len(p->cmd, CONST_STR_LEN("\n"));
 
-		if (-1 == (r = write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
+		if (-1 == (r = safe_write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
 			p->rrdtool_running = 0;
 
 			log_error_write(srv, __FILE__, __LINE__, "ss",
@@ -400,7 +441,7 @@ TRIGGER_FUNC(mod_rrd_trigger) {
 		}
 
 		buffer_prepare_copy(p->resp, 4096);
-		if (-1 == (r = read(p->read_fd, p->resp->ptr, p->resp->size))) {
+		if (-1 == (r = safe_read(p->read_fd, p->resp->ptr, p->resp->size))) {
 			p->rrdtool_running = 0;
 
 			log_error_write(srv, __FILE__, __LINE__, "ss",