Cleanup: Move all source files to src/

[lttng-modules.git] / src / lttng-context-hostname.c

diff --git a/src/lttng-context-hostname.c b/src/lttng-context-hostname.c
new file mode 100644 (file)
index 0000000..86c5d02
--- /dev/null
+++ b/src/lttng-context-hostname.c
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
+ * lttng-context-hostname.c
+ *
+ * LTTng hostname context.
+ *
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/utsname.h>
+#include <lttng/events.h>
+#include <ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <lttng/tracer.h>
+
+#define LTTNG_HOSTNAME_CTX_LEN (__NEW_UTS_LEN + 1)
+
+static
+size_t hostname_get_size(size_t offset)
+{
+       size_t size = 0;
+
+       size += LTTNG_HOSTNAME_CTX_LEN;
+       return size;
+}
+
+static
+void hostname_record(struct lttng_ctx_field *field,
+                struct lib_ring_buffer_ctx *ctx,
+                struct lttng_channel *chan)
+{
+       struct nsproxy *nsproxy;
+       struct uts_namespace *ns;
+       char *hostname;
+
+       /*
+        * No need to take the RCU read-side lock to read current
+        * nsproxy. (documented in nsproxy.h)
+        */
+       nsproxy = current->nsproxy;
+       if (nsproxy) {
+               ns = nsproxy->uts_ns;
+               hostname = ns->name.nodename;
+               chan->ops->event_write(ctx, hostname,
+                               LTTNG_HOSTNAME_CTX_LEN);
+       } else {
+               chan->ops->event_memset(ctx, 0,
+                               LTTNG_HOSTNAME_CTX_LEN);
+       }
+}
+
+static
+void hostname_get_value(struct lttng_ctx_field *field,
+               struct lttng_probe_ctx *lttng_probe_ctx,
+               union lttng_ctx_value *value)
+{
+       struct nsproxy *nsproxy;
+       struct uts_namespace *ns;
+       char *hostname;
+
+       /*
+        * No need to take the RCU read-side lock to read current
+        * nsproxy. (documented in nsproxy.h)
+        */
+       nsproxy = current->nsproxy;
+       if (nsproxy) {
+               ns = nsproxy->uts_ns;
+               hostname = ns->name.nodename;
+       } else {
+               hostname = "";
+       }
+       value->str = hostname;
+}
+
+static const struct lttng_type hostname_array_elem_type =
+       __type_integer(char, 0, 0, -1, __BYTE_ORDER, 10, UTF8);
+
+int lttng_add_hostname_to_ctx(struct lttng_ctx **ctx)
+{
+       struct lttng_ctx_field *field;
+
+       field = lttng_append_context(ctx);
+       if (!field)
+               return -ENOMEM;
+       if (lttng_find_context(*ctx, "hostname")) {
+               lttng_remove_context_field(ctx, field);
+               return -EEXIST;
+       }
+       field->event_field.name = "hostname";
+       field->event_field.type.atype = atype_array_nestable;
+       field->event_field.type.u.array_nestable.elem_type =
+               &hostname_array_elem_type;
+       field->event_field.type.u.array_nestable.length = LTTNG_HOSTNAME_CTX_LEN;
+       field->event_field.type.u.array_nestable.alignment = 0;
+
+       field->get_size = hostname_get_size;
+       field->record = hostname_record;
+       field->get_value = hostname_get_value;
+       lttng_context_update(*ctx);
+       wrapper_vmalloc_sync_mappings();
+       return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_add_hostname_to_ctx);