Enable agent application contexts if filter has such dependencies

[lttng-tools.git] / src / common / context.c

diff --git a/src/common/context.c b/src/common/context.c
new file mode 100644 (file)
index 0000000..ead6bb3
--- /dev/null
+++ b/src/common/context.c
@@ -0,0 +1,93 @@
+/*
+ * context.c
+ *
+ * LTTng context utilities.
+ *
+ * Copyright 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License, version 2.1 only,
+ * as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "context.h"
+#include <stddef.h>
+#include <string.h>
+#include <common/error.h>
+#include <common/macros.h>
+
+int parse_application_context(const char *str, char **out_provider_name,
+               char **out_ctx_name)
+{
+       const char app_ctx_prefix[] = "$app.";
+       char *provider_name = NULL, *ctx_name = NULL;
+       size_t i, len, colon_pos = 0, provider_name_len, ctx_name_len;
+
+       if (!str || !out_provider_name || !out_ctx_name) {
+               goto not_found;
+       }
+
+       len = strlen(str);
+       if (len <= sizeof(app_ctx_prefix) - 1) {
+               goto not_found;
+       }
+
+       /* String starts with $app. */
+       if (strncmp(str, app_ctx_prefix, sizeof(app_ctx_prefix) - 1)) {
+               goto not_found;
+       }
+
+       /* Validate that the ':' separator is present. */
+       for (i = sizeof(app_ctx_prefix); i < len; i++) {
+               const char c = str[i];
+
+               if (c == ':') {
+                       colon_pos = i;
+                       break;
+               }
+       }
+
+       /*
+        * No colon found or no ctx name ("$app.provider:") or no provider name
+        * given ("$app.:..."), which is invalid.
+        */
+       if (!colon_pos || colon_pos == len ||
+                       colon_pos == sizeof(app_ctx_prefix)) {
+               goto not_found;
+       }
+
+       provider_name_len = colon_pos - sizeof(app_ctx_prefix) + 2;
+       provider_name = zmalloc(provider_name_len);
+       if (!provider_name) {
+               PERROR("malloc provider_name");
+               goto not_found;
+       }
+       strncpy(provider_name, str + sizeof(app_ctx_prefix) - 1,
+                       provider_name_len - 1);
+
+       ctx_name_len = len - colon_pos;
+       ctx_name = zmalloc(ctx_name_len);
+       if (!ctx_name) {
+               PERROR("malloc ctx_name");
+               goto not_found;
+       }
+       strncpy(ctx_name, str + colon_pos + 1, ctx_name_len - 1);
+
+       *out_provider_name = provider_name;
+       *out_ctx_name = ctx_name;
+       return 0;
+not_found:
+       free(provider_name);
+       free(ctx_name);
+       return -1;
+}
+