1 files changed, 136 insertions, 0 deletions
diff --git a/src/core/lib/debug/trace.c b/src/core/lib/debug/trace.c
new file mode 100644
index 0000000000..786dd9324f
--- /dev/null
+++ b/src/core/lib/debug/trace.c
@@ -0,0 +1,136 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/debug/trace.h"
+
+#include <string.h>
+
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include "src/core/lib/support/env.h"
+
+typedef struct tracer {
+  const char *name;
+  int *flag;
+  struct tracer *next;
+} tracer;
+static tracer *tracers;
+
+void grpc_register_tracer(const char *name, int *flag) {
+  tracer *t = gpr_malloc(sizeof(*t));
+  t->name = name;
+  t->flag = flag;
+  t->next = tracers;
+  *flag = 0;
+  tracers = t;
+}
+
+static void add(const char *beg, const char *end, char ***ss, size_t *ns) {
+  size_t n = *ns;
+  size_t np = n + 1;
+  char *s;
+  size_t len;
+  GPR_ASSERT(end >= beg);
+  len = (size_t)(end - beg);
+  s = gpr_malloc(len + 1);
+  memcpy(s, beg, len);
+  s[len] = 0;
+  *ss = gpr_realloc(*ss, sizeof(char **) * np);
+  (*ss)[n] = s;
+  *ns = np;
+}
+
+static void split(const char *s, char ***ss, size_t *ns) {
+  const char *c = strchr(s, ',');
+  if (c == NULL) {
+    add(s, s + strlen(s), ss, ns);
+  } else {
+    add(s, c, ss, ns);
+    split(c + 1, ss, ns);
+  }
+}
+
+static void parse(const char *s) {
+  char **strings = NULL;
+  size_t nstrings = 0;
+  size_t i;
+  split(s, &strings, &nstrings);
+
+  for (i = 0; i < nstrings; i++) {
+    grpc_tracer_set_enabled(strings[i], 1);
+  }
+
+  for (i = 0; i < nstrings; i++) {
+    gpr_free(strings[i]);
+  }
+  gpr_free(strings);
+}
+
+void grpc_tracer_init(const char *env_var) {
+  char *e = gpr_getenv(env_var);
+  if (e != NULL) {
+    parse(e);
+    gpr_free(e);
+  }
+}
+
+void grpc_tracer_shutdown(void) {
+  while (tracers) {
+    tracer *t = tracers;
+    tracers = t->next;
+    gpr_free(t);
+  }
+}
+
+int grpc_tracer_set_enabled(const char *name, int enabled) {
+  tracer *t;
+  if (0 == strcmp(name, "all")) {
+    for (t = tracers; t; t = t->next) {
+      *t->flag = 1;
+    }
+  } else {
+    int found = 0;
+    for (t = tracers; t; t = t->next) {
+      if (0 == strcmp(name, t->name)) {
+        *t->flag = enabled;
+        found = 1;
+      }
+    }
+    if (!found) {
+      gpr_log(GPR_ERROR, "Unknown trace var: '%s'", name);
+      return 0; /* early return */
+    }
+  }
+  return 1;
+}