X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-context-cgroup-ns.c;fp=lttng-context-cgroup-ns.c;h=81486e514a592d96affa30f8e55880253c16cc48;hb=a6cf40a4491954d6f81052f8bbce757f73727f16;hp=0000000000000000000000000000000000000000;hpb=47491cdffd394f09524657e9be1e90d4bb644f2f;p=lttng-modules.git

diff --git a/lttng-context-cgroup-ns.c b/lttng-context-cgroup-ns.c
new file mode 100644
index 00000000..81486e51
--- /dev/null
+++ b/lttng-context-cgroup-ns.c
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
+ * lttng-context-cgroup-ns.c
+ *
+ * LTTng cgroup namespace context.
+ *
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *               2019 Michael Jeanson <mjeanson@efficios.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/cgroup.h>
+#include <lttng-events.h>
+#include <wrapper/ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <wrapper/namespace.h>
+#include <lttng-tracer.h>
+
+#if defined(CONFIG_CGROUPS) && \
+	((LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0)) || \
+	 LTTNG_UBUNTU_KERNEL_RANGE(4,4,0,0, 4,5,0,0))
+
+static
+size_t cgroup_ns_get_size(size_t offset)
+{
+	size_t size = 0;
+
+	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
+	size += sizeof(unsigned int);
+	return size;
+}
+
+static
+void cgroup_ns_record(struct lttng_ctx_field *field,
+		 struct lib_ring_buffer_ctx *ctx,
+		 struct lttng_channel *chan)
+{
+	unsigned int cgroup_ns_inum = 0;
+
+	/*
+	 * nsproxy can be NULL when scheduled out of exit.
+	 *
+	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
+	 * precautions should be taken when accessing the current task's
+	 * namespaces, just dereference the pointers.
+	 */
+	if (current->nsproxy)
+		cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;
+
+	lib_ring_buffer_align_ctx(ctx, lttng_alignof(cgroup_ns_inum));
+	chan->ops->event_write(ctx, &cgroup_ns_inum, sizeof(cgroup_ns_inum));
+}
+
+static
+void cgroup_ns_get_value(struct lttng_ctx_field *field,
+		struct lttng_probe_ctx *lttng_probe_ctx,
+		union lttng_ctx_value *value)
+{
+	unsigned int cgroup_ns_inum = 0;
+
+	/*
+	 * nsproxy can be NULL when scheduled out of exit.
+	 *
+	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
+	 * precautions should be taken when accessing the current task's
+	 * namespaces, just dereference the pointers.
+	 */
+	if (current->nsproxy)
+		cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;
+
+	value->s64 = cgroup_ns_inum;
+}
+
+int lttng_add_cgroup_ns_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, "cgroup_ns")) {
+		lttng_remove_context_field(ctx, field);
+		return -EEXIST;
+	}
+	field->event_field.name = "cgroup_ns";
+	field->event_field.type.atype = atype_integer;
+	field->event_field.type.u.basic.integer.size = sizeof(unsigned int) * CHAR_BIT;
+	field->event_field.type.u.basic.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
+	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(unsigned int);
+	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
+	field->event_field.type.u.basic.integer.base = 10;
+	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
+	field->get_size = cgroup_ns_get_size;
+	field->record = cgroup_ns_record;
+	field->get_value = cgroup_ns_get_value;
+	lttng_context_update(*ctx);
+	wrapper_vmalloc_sync_all();
+	return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_add_cgroup_ns_to_ctx);
+
+#endif