+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com>
- *
- * LTTng UST namespaced real user ID context.
- */
-
-#define _LGPL_SOURCE
-#include <limits.h>
-#include <stddef.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <lttng/ust-events.h>
-#include <lttng/ust-tracer.h>
-#include <lttng/ringbuffer-context.h>
-
-#include "context-internal.h"
-#include "creds.h"
-
-
-/*
- * At the kernel level, user IDs and group IDs are a per-thread attribute.
- * However, POSIX requires that all threads in a process share the same
- * credentials. The NPTL threading implementation handles the POSIX
- * requirements by providing wrapper functions for the various system calls
- * that change process UIDs and GIDs. These wrapper functions (including those
- * for setreuid() and setregid()) employ a signal-based technique to ensure
- * that when one thread changes credentials, all of the other threads in the
- * process also change their credentials.
- */
-
-/*
- * We cache the result to ensure we don't trigger a system call for
- * each event. User / group IDs are global to the process.
- */
-static uid_t cached_vuid = INVALID_UID;
-
-static
-uid_t get_vuid(void)
-{
- uid_t vuid;
-
- vuid = CMM_LOAD_SHARED(cached_vuid);
-
- if (caa_unlikely(vuid == INVALID_UID)) {
- vuid = getuid();
- CMM_STORE_SHARED(cached_vuid, vuid);
- }
-
- return vuid;
-}
-
-/*
- * The vuid can change on setuid, setreuid and setresuid.
- */
-void lttng_context_vuid_reset(void)
-{
- CMM_STORE_SHARED(cached_vuid, INVALID_UID);
-}
-
-static
-size_t vuid_get_size(struct lttng_ust_ctx_field *field, size_t offset)
-{
- size_t size = 0;
-
- size += lib_ring_buffer_align(offset, lttng_alignof(uid_t));
- size += sizeof(uid_t);
- return size;
-}
-
-static
-void vuid_record(struct lttng_ust_ctx_field *field,
- struct lttng_ust_lib_ring_buffer_ctx *ctx,
- struct lttng_ust_channel_buffer *chan)
-{
- uid_t vuid;
-
- vuid = get_vuid();
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(vuid));
- chan->ops->event_write(ctx, &vuid, sizeof(vuid));
-}
-
-static
-void vuid_get_value(struct lttng_ust_ctx_field *field,
- struct lttng_ust_ctx_value *value)
-{
- value->u.s64 = get_vuid();
-}
-
-int lttng_add_vuid_to_ctx(struct lttng_ust_ctx **ctx)
-{
- struct lttng_ust_ctx_field *field;
- struct lttng_ust_type_common *type;
- int ret;
-
- type = lttng_ust_create_type_integer(sizeof(uid_t) * CHAR_BIT,
- lttng_alignof(uid_t) * CHAR_BIT,
- lttng_ust_is_signed_type(uid_t),
- BYTE_ORDER, 10);
- if (!type)
- return -ENOMEM;
- field = lttng_append_context(ctx);
- if (!field) {
- ret = -ENOMEM;
- goto error_context;
- }
- if (lttng_find_context(*ctx, "vuid")) {
- ret = -EEXIST;
- goto error_find_context;
- }
- field->event_field->name = strdup("vuid");
- if (!field->event_field->name) {
- ret = -ENOMEM;
- goto error_name;
- }
- field->event_field->type = type;
- field->get_size = vuid_get_size;
- field->record = vuid_record;
- field->get_value = vuid_get_value;
- lttng_context_update(*ctx);
- return 0;
-
-error_name:
-error_find_context:
- lttng_remove_context_field(ctx, field);
-error_context:
- lttng_ust_destroy_type(type);
- return ret;
-}