On 4/5/24 1:44 PM, Dev Jain wrote:
> This patch introduces an ELF parsing test; the 5th byte of the ELF header
> must be 0x01 for a 32-bit process. A basic sanity check is required to ensure
> that we are actually testing a 32-bit build.
>
> Signed-off-by: Dev Jain <dev.j...@arm.com>
> ---
> tools/testing/selftests/arm/elf/parse_elf.c | 75 +++++++++++++++++++++
> 1 file changed, 75 insertions(+)
> create mode 100644 tools/testing/selftests/arm/elf/parse_elf.c
>
> diff --git a/tools/testing/selftests/arm/elf/parse_elf.c
> b/tools/testing/selftests/arm/elf/parse_elf.c
> new file mode 100644
> index 000000000000..decd65699858
> --- /dev/null
> +++ b/tools/testing/selftests/arm/elf/parse_elf.c
> @@ -0,0 +1,75 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2024 ARM Limited
> + *
> + * Author : Dev Jain <dev.j...@arm.com>
> + *
> + * Parse elf header to confirm 32-bit process
> + */
> +
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <elf.h>
> +#include <stdint.h>
> +
> +#include <kselftest.h>
> +
> +/* The ELF file header. This appears at the start of every ELF file. */
> +
> +struct elf_header {
> + unsigned char e_ident[16]; /* Magic number and other info */
> + uint16_t e_type; /* Object file type */
> + uint16_t e_machine; /* Architecture */
> + uint32_t e_version; /* Object file version */
> + uint64_t e_entry; /* Entry point virtual address */
> + uint64_t e_phoff; /* Program header table file offset */
> + uint64_t e_shoff; /* Section header table file offset */
> + uint32_t e_flags; /* Processor-specific flags */
> + uint16_t e_ehsize; /* ELF header size in bytes */
> + uint16_t e_phentsize; /* Program header table entry size */
> + uint16_t e_phnum; /* Program header table entry count */
> + uint16_t e_shentsize; /* Section header table entry size */
> + uint16_t e_shnum; /* Section header table entry count */
> + uint16_t e_shstrndx; /* Section header string table index */
> +};
> +
> +static int read_elf_header(const char *elfFile)
> +{
> + struct elf_header header;
> + FILE *file;
> +
> + file = fopen(elfFile, "r");
> + if (file) {
> +
> + /* store header in struct */
> + fread(&header, 1, sizeof(header), file);
> + fclose(file);
> +
> + /* sanity check: does it really follow ELF format */
> + if (header.e_ident[0] == 0x7f &&
> + header.e_ident[1] == 'E' &&
> + header.e_ident[2] == 'L' &&
> + header.e_ident[3] == 'F') {
> + if (header.e_ident[4] == 0x01)
> + return 0;
> + return 1;
> + }
> + ksft_exit_fail_msg("Cannot parse /proc/self/exe\n");
> + }
> + ksft_exit_fail_msg("Cannot open /proc/self/exe\n");
> + exit(EXIT_FAILURE);
Instead of failing and exiting multiple times here, use ksft_print_msg,
return error or -1 from here and fail the test case in ksft_test_result().
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + const char *file_name;
> +
> + ksft_print_header();
> + ksft_set_plan(1);
> +
> + file_name = "/proc/self/exe";
> + ksft_test_result(read_elf_header(file_name) == 0, "ELF is 32 bit\n");
> + ksft_finished();
> +}
--
BR,
Muhammad Usama Anjum
