linux/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Google */

#include <test_progs.h>
#include <bpf/libbpf.h>
#include <bpf/btf.h>
#include "dmabuf_iter.skel.h"

#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>

#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
#include <linux/udmabuf.h>

static int udmabuf = -1;
static const char udmabuf_test_buffer_name[DMA_BUF_NAME_LEN] = "udmabuf_test_buffer_for_iter";
static size_t udmabuf_test_buffer_size;
static int sysheap_dmabuf = -1;
static const char sysheap_test_buffer_name[DMA_BUF_NAME_LEN] = "sysheap_test_buffer_for_iter";
static size_t sysheap_test_buffer_size;

static int create_udmabuf(void)
{
	struct udmabuf_create create;
	int dev_udmabuf, memfd, local_udmabuf;

	udmabuf_test_buffer_size = 10 * getpagesize();

	if (!ASSERT_LE(sizeof(udmabuf_test_buffer_name), DMA_BUF_NAME_LEN, "NAMETOOLONG"))
		return -1;

	memfd = memfd_create("memfd_test", MFD_ALLOW_SEALING);
	if (!ASSERT_OK_FD(memfd, "memfd_create"))
		return -1;

	if (!ASSERT_OK(ftruncate(memfd, udmabuf_test_buffer_size), "ftruncate"))
		goto close_memfd;

	if (!ASSERT_OK(fcntl(memfd, F_ADD_SEALS, F_SEAL_SHRINK), "seal"))
		goto close_memfd;

	dev_udmabuf = open("/dev/udmabuf", O_RDONLY);
	if (!ASSERT_OK_FD(dev_udmabuf, "open udmabuf"))
		goto close_memfd;

	memset(&create, 0, sizeof(create));
	create.memfd = memfd;
	create.flags = UDMABUF_FLAGS_CLOEXEC;
	create.offset = 0;
	create.size = udmabuf_test_buffer_size;

	local_udmabuf = ioctl(dev_udmabuf, UDMABUF_CREATE, &create);
	close(dev_udmabuf);
	if (!ASSERT_OK_FD(local_udmabuf, "udmabuf_create"))
		goto close_memfd;

	if (!ASSERT_OK(ioctl(local_udmabuf, DMA_BUF_SET_NAME_B, udmabuf_test_buffer_name), "name"))
		goto close_udmabuf;

	return local_udmabuf;

close_udmabuf:
	close(local_udmabuf);
close_memfd:
	close(memfd);
	return -1;
}

static int create_sys_heap_dmabuf(void)
{
	sysheap_test_buffer_size = 20 * getpagesize();

	struct dma_heap_allocation_data data = {
		.len = sysheap_test_buffer_size,
		.fd = 0,
		.fd_flags = O_RDWR | O_CLOEXEC,
		.heap_flags = 0,
	};
	int heap_fd, ret;

	if (!ASSERT_LE(sizeof(sysheap_test_buffer_name), DMA_BUF_NAME_LEN, "NAMETOOLONG"))
		return -1;

	heap_fd = open("/dev/dma_heap/system", O_RDONLY);
	if (!ASSERT_OK_FD(heap_fd, "open dma heap"))
		return -1;

	ret = ioctl(heap_fd, DMA_HEAP_IOCTL_ALLOC, &data);
	close(heap_fd);
	if (!ASSERT_OK(ret, "syheap alloc"))
		return -1;

	if (!ASSERT_OK(ioctl(data.fd, DMA_BUF_SET_NAME_B, sysheap_test_buffer_name), "name"))
		goto close_sysheap_dmabuf;

	return data.fd;

close_sysheap_dmabuf:
	close(data.fd);
	return -1;
}

static int create_test_buffers(void)
{
	udmabuf = create_udmabuf();
	sysheap_dmabuf = create_sys_heap_dmabuf();

	if (udmabuf < 0 || sysheap_dmabuf < 0)
		return -1;

	return 0;
}

static void destroy_test_buffers(void)
{
	close(udmabuf);
	udmabuf = -1;

	close(sysheap_dmabuf);
	sysheap_dmabuf = -1;
}

enum Fields { INODE, SIZE, NAME, EXPORTER, FIELD_COUNT };
struct DmabufInfo {
	unsigned long inode;
	unsigned long size;
	char name[DMA_BUF_NAME_LEN];
	char exporter[32];
};

static bool check_dmabuf_info(const struct DmabufInfo *bufinfo,
			      unsigned long size,
			      const char *name, const char *exporter)
{
	return size == bufinfo->size &&
	       !strcmp(name, bufinfo->name) &&
	       !strcmp(exporter, bufinfo->exporter);
}

static void subtest_dmabuf_iter_check_no_infinite_reads(struct dmabuf_iter *skel)
{
	int iter_fd;
	char buf[256];

	iter_fd = bpf_iter_create(bpf_link__fd(skel->links.dmabuf_collector));
	if (!ASSERT_OK_FD(iter_fd, "iter_create"))
		return;

	while (read(iter_fd, buf, sizeof(buf)) > 0)
		; /* Read out all contents */

	/* Next reads should return 0 */
	ASSERT_EQ(read(iter_fd, buf, sizeof(buf)), 0, "read");

	close(iter_fd);
}

static void subtest_dmabuf_iter_check_default_iter(struct dmabuf_iter *skel)
{
	bool found_test_sysheap_dmabuf = false;
	bool found_test_udmabuf = false;
	struct DmabufInfo bufinfo;
	size_t linesize = 0;
	char *line = NULL;
	FILE *iter_file;
	int iter_fd, f = INODE;

	iter_fd = bpf_iter_create(bpf_link__fd(skel->links.dmabuf_collector));
	if (!ASSERT_OK_FD(iter_fd, "iter_create"))
		return;

	iter_file = fdopen(iter_fd, "r");
	if (!ASSERT_OK_PTR(iter_file, "fdopen"))
		goto close_iter_fd;

	while (getline(&line, &linesize, iter_file) != -1) {
		if (f % FIELD_COUNT == INODE) {
			ASSERT_EQ(sscanf(line, "%ld", &bufinfo.inode), 1,
				  "read inode");
		} else if (f % FIELD_COUNT == SIZE) {
			ASSERT_EQ(sscanf(line, "%ld", &bufinfo.size), 1,
				  "read size");
		} else if (f % FIELD_COUNT == NAME) {
			ASSERT_EQ(sscanf(line, "%s", bufinfo.name), 1,
				  "read name");
		} else if (f % FIELD_COUNT == EXPORTER) {
			ASSERT_EQ(sscanf(line, "%31s", bufinfo.exporter), 1,
				  "read exporter");

			if (check_dmabuf_info(&bufinfo,
					      sysheap_test_buffer_size,
					      sysheap_test_buffer_name,
					      "system"))
				found_test_sysheap_dmabuf = true;
			else if (check_dmabuf_info(&bufinfo,
						   udmabuf_test_buffer_size,
						   udmabuf_test_buffer_name,
						   "udmabuf"))
				found_test_udmabuf = true;
		}
		++f;
	}

	ASSERT_EQ(f % FIELD_COUNT, INODE, "number of fields");

	ASSERT_TRUE(found_test_sysheap_dmabuf, "found_test_sysheap_dmabuf");
	ASSERT_TRUE(found_test_udmabuf, "found_test_udmabuf");

	free(line);
	fclose(iter_file);
close_iter_fd:
	close(iter_fd);
}

static void subtest_dmabuf_iter_check_open_coded(struct dmabuf_iter *skel, int map_fd)
{
	LIBBPF_OPTS(bpf_test_run_opts, topts);
	char key[DMA_BUF_NAME_LEN];
	int err, fd;
	bool found;

	/* No need to attach it, just run it directly */
	fd = bpf_program__fd(skel->progs.iter_dmabuf_for_each);

	err = bpf_prog_test_run_opts(fd, &topts);
	if (!ASSERT_OK(err, "test_run_opts err"))
		return;
	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
		return;

	if (!ASSERT_OK(bpf_map_get_next_key(map_fd, NULL, key), "get next key"))
		return;

	do {
		ASSERT_OK(bpf_map_lookup_elem(map_fd, key, &found), "lookup");
		ASSERT_TRUE(found, "found test buffer");
	} while (bpf_map_get_next_key(map_fd, key, key));
}

void test_dmabuf_iter(void)
{
	struct dmabuf_iter *skel = NULL;
	int map_fd;
	const bool f = false;

	skel = dmabuf_iter__open_and_load();
	if (!ASSERT_OK_PTR(skel, "dmabuf_iter__open_and_load"))
		return;

	map_fd = bpf_map__fd(skel->maps.testbuf_hash);
	if (!ASSERT_OK_FD(map_fd, "map_fd"))
		goto destroy_skel;

	if (!ASSERT_OK(bpf_map_update_elem(map_fd, udmabuf_test_buffer_name, &f, BPF_ANY),
		       "insert udmabuf"))
		goto destroy_skel;
	if (!ASSERT_OK(bpf_map_update_elem(map_fd, sysheap_test_buffer_name, &f, BPF_ANY),
		       "insert sysheap buffer"))
		goto destroy_skel;

	if (!ASSERT_OK(create_test_buffers(), "create_test_buffers"))
		goto destroy;

	if (!ASSERT_OK(dmabuf_iter__attach(skel), "skel_attach"))
		goto destroy;

	if (test__start_subtest("no_infinite_reads"))
		subtest_dmabuf_iter_check_no_infinite_reads(skel);
	if (test__start_subtest("default_iter"))
		subtest_dmabuf_iter_check_default_iter(skel);
	if (test__start_subtest("open_coded"))
		subtest_dmabuf_iter_check_open_coded(skel, map_fd);

destroy:
	destroy_test_buffers();
destroy_skel:
	dmabuf_iter__destroy(skel);
}