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828226b69f
Add a basic test for the ability to mmap /sys/kernel/btf/vmlinux. Ensure that the data is valid BTF and that it is padded with zero. Signed-off-by: Lorenz Bauer <lmb@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20250520-vmlinux-mmap-v5-2-e8c941acc414@isovalent.com
82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
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/* Copyright (c) 2025 Isovalent */
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#include <test_progs.h>
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#include <bpf/btf.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <fcntl.h>
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#include <unistd.h>
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static void test_btf_mmap_sysfs(const char *path, struct btf *base)
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{
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struct stat st;
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__u64 btf_size, end;
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void *raw_data = NULL;
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int fd = -1;
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long page_size;
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struct btf *btf = NULL;
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page_size = sysconf(_SC_PAGESIZE);
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if (!ASSERT_GE(page_size, 0, "get_page_size"))
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goto cleanup;
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if (!ASSERT_OK(stat(path, &st), "stat_btf"))
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goto cleanup;
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btf_size = st.st_size;
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end = (btf_size + page_size - 1) / page_size * page_size;
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fd = open(path, O_RDONLY);
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if (!ASSERT_GE(fd, 0, "open_btf"))
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goto cleanup;
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raw_data = mmap(NULL, btf_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_writable"))
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goto cleanup;
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raw_data = mmap(NULL, btf_size, PROT_READ, MAP_SHARED, fd, 0);
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if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_shared"))
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goto cleanup;
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raw_data = mmap(NULL, end + 1, PROT_READ, MAP_PRIVATE, fd, 0);
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if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_invalid_size"))
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goto cleanup;
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raw_data = mmap(NULL, end, PROT_READ, MAP_PRIVATE, fd, 0);
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if (!ASSERT_OK_PTR(raw_data, "mmap_btf"))
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goto cleanup;
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if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_WRITE), -1,
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"mprotect_writable"))
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goto cleanup;
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if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_EXEC), -1,
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"mprotect_executable"))
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goto cleanup;
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/* Check padding is zeroed */
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for (int i = btf_size; i < end; i++) {
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if (((__u8 *)raw_data)[i] != 0) {
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PRINT_FAIL("tail of BTF is not zero at page offset %d\n", i);
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goto cleanup;
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}
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}
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btf = btf__new_split(raw_data, btf_size, base);
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if (!ASSERT_OK_PTR(btf, "parse_btf"))
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goto cleanup;
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cleanup:
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btf__free(btf);
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if (raw_data && raw_data != MAP_FAILED)
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munmap(raw_data, btf_size);
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if (fd >= 0)
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close(fd);
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}
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void test_btf_sysfs(void)
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{
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test_btf_mmap_sysfs("/sys/kernel/btf/vmlinux", NULL);
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}
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