--- /dev/null
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
+ * lttng-context.c
+ *
+ * LTTng trace/channel/event context management.
+ *
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_mappings() */
+#include <lttng/events.h>
+#include <lttng/tracer.h>
+
+/*
+ * The filter implementation requires that two consecutive "get" for the
+ * same context performed by the same thread return the same result.
+ */
+
+/*
+ * Static array of contexts, for $ctx filters.
+ */
+struct lttng_ctx *lttng_static_ctx;
+
+int lttng_find_context(struct lttng_ctx *ctx, const char *name)
+{
+ unsigned int i;
+
+ for (i = 0; i < ctx->nr_fields; i++) {
+ /* Skip allocated (but non-initialized) contexts */
+ if (!ctx->fields[i].event_field.name)
+ continue;
+ if (!strcmp(ctx->fields[i].event_field.name, name))
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_find_context);
+
+int lttng_get_context_index(struct lttng_ctx *ctx, const char *name)
+{
+ unsigned int i;
+ const char *subname;
+
+ if (!ctx)
+ return -1;
+ if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
+ subname = name + strlen("$ctx.");
+ } else {
+ subname = name;
+ }
+ for (i = 0; i < ctx->nr_fields; i++) {
+ /* Skip allocated (but non-initialized) contexts */
+ if (!ctx->fields[i].event_field.name)
+ continue;
+ if (!strcmp(ctx->fields[i].event_field.name, subname))
+ return i;
+ }
+ return -1;
+}
+EXPORT_SYMBOL_GPL(lttng_get_context_index);
+
+/*
+ * Note: as we append context information, the pointer location may change.
+ */
+struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
+{
+ struct lttng_ctx_field *field;
+ struct lttng_ctx *ctx;
+
+ if (!*ctx_p) {
+ *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
+ if (!*ctx_p)
+ return NULL;
+ (*ctx_p)->largest_align = 1;
+ }
+ ctx = *ctx_p;
+ if (ctx->nr_fields + 1 > ctx->allocated_fields) {
+ struct lttng_ctx_field *new_fields;
+
+ ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
+ new_fields = lttng_kvzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
+ if (!new_fields)
+ return NULL;
+ if (ctx->fields)
+ memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields);
+ lttng_kvfree(ctx->fields);
+ ctx->fields = new_fields;
+ }
+ field = &ctx->fields[ctx->nr_fields];
+ ctx->nr_fields++;
+ return field;
+}
+EXPORT_SYMBOL_GPL(lttng_append_context);
+
+/*
+ * lttng_context_update() should be called at least once between context
+ * modification and trace start.
+ */
+void lttng_context_update(struct lttng_ctx *ctx)
+{
+ int i;
+ size_t largest_align = 8; /* in bits */
+
+ for (i = 0; i < ctx->nr_fields; i++) {
+ struct lttng_type *type;
+ size_t field_align = 8;
+
+ type = &ctx->fields[i].event_field.type;
+ switch (type->atype) {
+ case atype_integer:
+ field_align = type->u.integer.alignment;
+ break;
+ case atype_array_nestable:
+ {
+ const struct lttng_type *nested_type;
+
+ nested_type = type->u.array_nestable.elem_type;
+ switch (nested_type->atype) {
+ case atype_integer:
+ field_align = nested_type->u.integer.alignment;
+ break;
+ case atype_string:
+ break;
+
+ case atype_array_nestable:
+ case atype_sequence_nestable:
+ case atype_struct_nestable:
+ case atype_variant_nestable:
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+ field_align = max_t(size_t, field_align,
+ type->u.array_nestable.alignment);
+ break;
+ }
+ case atype_sequence_nestable:
+ {
+ const struct lttng_type *nested_type;
+
+ nested_type = type->u.sequence_nestable.elem_type;
+ switch (nested_type->atype) {
+ case atype_integer:
+ field_align = nested_type->u.integer.alignment;
+ break;
+
+ case atype_string:
+ break;
+
+ case atype_array_nestable:
+ case atype_sequence_nestable:
+ case atype_struct_nestable:
+ case atype_variant_nestable:
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+ field_align = max_t(size_t, field_align,
+ type->u.sequence_nestable.alignment);
+ break;
+ }
+ case atype_string:
+ break;
+
+ case atype_struct_nestable:
+ case atype_variant_nestable:
+ break;
+
+ case atype_enum_nestable:
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+ largest_align = max_t(size_t, largest_align, field_align);
+ }
+ ctx->largest_align = largest_align >> 3; /* bits to bytes */
+}
+
+/*
+ * Remove last context field.
+ */
+void lttng_remove_context_field(struct lttng_ctx **ctx_p,
+ struct lttng_ctx_field *field)
+{
+ struct lttng_ctx *ctx;
+
+ ctx = *ctx_p;
+ ctx->nr_fields--;
+ WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
+ memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
+}
+EXPORT_SYMBOL_GPL(lttng_remove_context_field);
+
+void lttng_destroy_context(struct lttng_ctx *ctx)
+{
+ int i;
+
+ if (!ctx)
+ return;
+ for (i = 0; i < ctx->nr_fields; i++) {
+ if (ctx->fields[i].destroy)
+ ctx->fields[i].destroy(&ctx->fields[i]);
+ }
+ lttng_kvfree(ctx->fields);
+ kfree(ctx);
+}
+
+int lttng_context_init(void)
+{
+ int ret;
+
+ ret = lttng_add_hostname_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_hostname_to_ctx");
+ }
+ ret = lttng_add_nice_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_nice_to_ctx");
+ }
+ ret = lttng_add_pid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_pid_to_ctx");
+ }
+ ret = lttng_add_ppid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_ppid_to_ctx");
+ }
+ ret = lttng_add_prio_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_prio_to_ctx");
+ }
+ ret = lttng_add_procname_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
+ }
+ ret = lttng_add_tid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_tid_to_ctx");
+ }
+ ret = lttng_add_vppid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_vppid_to_ctx");
+ }
+ ret = lttng_add_vtid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
+ }
+ ret = lttng_add_vpid_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
+ }
+ ret = lttng_add_cpu_id_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_cpu_id_to_ctx");
+ }
+ ret = lttng_add_interruptible_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_interruptible_to_ctx");
+ }
+ ret = lttng_add_need_reschedule_to_ctx(<tng_static_ctx);
+ if (ret) {
+ printk(KERN_WARNING "Cannot add context lttng_add_need_reschedule_to_ctx");
+ }
+ ret = lttng_add_preemptible_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_preemptible_to_ctx");
+ }
+ ret = lttng_add_migratable_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_migratable_to_ctx");
+ }
+ ret = lttng_add_cgroup_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_cgroup_ns_to_ctx");
+ }
+ ret = lttng_add_ipc_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_ipc_ns_to_ctx");
+ }
+ ret = lttng_add_mnt_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_mnt_ns_to_ctx");
+ }
+ ret = lttng_add_net_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_net_ns_to_ctx");
+ }
+ ret = lttng_add_pid_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_pid_ns_to_ctx");
+ }
+ ret = lttng_add_user_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_user_ns_to_ctx");
+ }
+ ret = lttng_add_uts_ns_to_ctx(<tng_static_ctx);
+ if (ret && ret != -ENOSYS) {
+ printk(KERN_WARNING "Cannot add context lttng_add_uts_ns_to_ctx");
+ }
+ /* TODO: perf counters for filtering */
+ return 0;
+}
+
+void lttng_context_exit(void)
+{
+ lttng_destroy_context(lttng_static_ctx);
+ lttng_static_ctx = NULL;
+}
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