+++ /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 group ID context.
- */
-
-#define _LGPL_SOURCE
-#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 gid_t cached_vgid = INVALID_GID;
-
-static
-gid_t get_vgid(void)
-{
- gid_t vgid;
-
- vgid = CMM_LOAD_SHARED(cached_vgid);
-
- if (caa_unlikely(cached_vgid == (gid_t) -1)) {
- vgid = getgid();
- CMM_STORE_SHARED(cached_vgid, vgid);
- }
-
- return vgid;
-}
-
-/*
- * The vgid can change on setuid, setreuid and setresuid.
- */
-void lttng_context_vgid_reset(void)
-{
- CMM_STORE_SHARED(cached_vgid, INVALID_GID);
-}
-
-static
-size_t vgid_get_size(struct lttng_ust_ctx_field *field, size_t offset)
-{
- size_t size = 0;
-
- size += lib_ring_buffer_align(offset, lttng_alignof(gid_t));
- size += sizeof(gid_t);
- return size;
-}
-
-static
-void vgid_record(struct lttng_ust_ctx_field *field,
- struct lttng_ust_lib_ring_buffer_ctx *ctx,
- struct lttng_ust_channel_buffer *chan)
-{
- gid_t vgid;
-
- vgid = get_vgid();
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(vgid));
- chan->ops->event_write(ctx, &vgid, sizeof(vgid));
-}
-
-static
-void vgid_get_value(struct lttng_ust_ctx_field *field,
- struct lttng_ust_ctx_value *value)
-{
- value->u.s64 = get_vgid();
-}
-
-int lttng_add_vgid_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(gid_t) * CHAR_BIT,
- lttng_alignof(gid_t) * CHAR_BIT,
- lttng_is_signed_type(gid_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, "vgid")) {
- ret = -EEXIST;
- goto error_find_context;
- }
- field->event_field->name = strdup("vgid");
- if (!field->event_field->name) {
- ret = -ENOMEM;
- goto error_name;
- }
- field->event_field->type = type;
- field->get_size = vgid_get_size;
- field->record = vgid_record;
- field->get_value = vgid_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;
-}