X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=src%2Fwrite_prometheus.c;h=991415ef08713ddb7939e63fd7d5d196a3d35981;hb=98e38add333bfcb893fcde408ecf3a0c43d99e31;hp=43a60fc980d4ef8f0332e239ae09e4737705870a;hpb=c53c496b6db4e11fd8aed8df9556dad481220196;p=collectd.git

diff --git a/src/write_prometheus.c b/src/write_prometheus.c
index 43a60fc9..991415ef 100644
--- a/src/write_prometheus.c
+++ b/src/write_prometheus.c
@@ -37,7 +37,7 @@
 #include <microhttpd.h>
 
 #ifndef PROMETHEUS_DEFAULT_STALENESS_DELTA
-#define PROMETHEUS_DEFAULT_STALENESS_DELTA TIME_T_TO_CDTIME_T(300)
+#define PROMETHEUS_DEFAULT_STALENESS_DELTA TIME_T_TO_CDTIME_T_STATIC(300)
 #endif
 
 #define VARINT_UINT32_BYTES 5
@@ -98,6 +98,43 @@ static void format_protobuf(ProtobufCBuffer *buffer) {
   pthread_mutex_unlock(&metrics_lock);
 }
 
+static char const *escape_label_value(char *buffer, size_t buffer_size,
+                                      char const *value) {
+  /* shortcut for values that don't need escaping. */
+  if (strpbrk(value, "\n\"\\") == NULL)
+    return value;
+
+  size_t value_len = strlen(value);
+  size_t buffer_len = 0;
+
+  for (size_t i = 0; i < value_len; i++) {
+    switch (value[i]) {
+    case '\n':
+    case '"':
+    case '\\':
+      if ((buffer_size - buffer_len) < 3) {
+        break;
+      }
+      buffer[buffer_len] = '\\';
+      buffer[buffer_len + 1] = (value[i] == '\n') ? 'n' : value[i];
+      buffer_len += 2;
+      break;
+
+    default:
+      if ((buffer_size - buffer_len) < 2) {
+        break;
+      }
+      buffer[buffer_len] = value[i];
+      buffer_len++;
+      break;
+    }
+  }
+
+  assert(buffer_len < buffer_size);
+  buffer[buffer_len] = 0;
+  return buffer;
+}
+
 /* format_labels formats a metric's labels in Prometheus-compatible format. This
  * format looks like this:
  *
@@ -109,16 +146,22 @@ static char *format_labels(char *buffer, size_t buffer_size,
   assert(m->n_label >= 1);
   assert(m->n_label <= 3);
 
-#define LABEL_BUFFER_SIZE (2 * DATA_MAX_NAME_LEN + 4)
+#define LABEL_KEY_SIZE DATA_MAX_NAME_LEN
+#define LABEL_VALUE_SIZE (2 * DATA_MAX_NAME_LEN - 1)
+#define LABEL_BUFFER_SIZE (LABEL_KEY_SIZE + LABEL_VALUE_SIZE + 4)
 
   char *labels[3] = {
       (char[LABEL_BUFFER_SIZE]){0}, (char[LABEL_BUFFER_SIZE]){0},
       (char[LABEL_BUFFER_SIZE]){0},
   };
 
-  for (size_t i = 0; i < m->n_label; i++)
+  /* N.B.: the label *names* are hard-coded by this plugin and therefore we
+   * know that they are sane. */
+  for (size_t i = 0; i < m->n_label; i++) {
+    char value[LABEL_VALUE_SIZE];
     ssnprintf(labels[i], LABEL_BUFFER_SIZE, "%s=\"%s\"", m->label[i]->name,
-              m->label[i]->value);
+              escape_label_value(value, sizeof(value), m->label[i]->value));
+  }
 
   strjoin(buffer, buffer_size, labels, m->n_label, ",");
   return buffer;
@@ -210,12 +253,11 @@ static int http_handler(void *cls, struct MHD_Connection *connection,
   else
     format_text(buffer);
 
-  struct MHD_Response *res =
 #if defined(MHD_VERSION) && MHD_VERSION >= 0x00090500
-    MHD_create_response_from_buffer(
+  struct MHD_Response *res = MHD_create_response_from_buffer(
       simple.len, simple.data, MHD_RESPMEM_MUST_COPY);
 #else
-    MHD_create_response_from_data(
+  struct MHD_Response *res = MHD_create_response_from_data(
       simple.len, simple.data, /* must_free = */ 0, /* must_copy = */ 1);
 #endif
   MHD_add_response_header(res, MHD_HTTP_HEADER_CONTENT_TYPE,