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.jain@arm.com --- tools/testing/selftests/arm/elf/parse_elf.c | 74 +++++++++++++++++++++ 1 file changed, 74 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..86a2ec88b47d --- /dev/null +++ b/tools/testing/selftests/arm/elf/parse_elf.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2024 ARM Limited + * + * Author : Dev Jain dev.jain@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; + int ret = -1; + + 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) + ret = 0; + } else { + ksft_print_msg("Cannot parse /proc/self/exe\n"); + } + } else { + ksft_print_msg("Cannot open /proc/self/exe\n"); + } + return ret; +} + +int main(int argc, char *argv[]) +{ + ksft_print_header(); + ksft_set_plan(1); + + ksft_test_result(read_elf_header("/proc/self/exe") == 0, "ELF is 32 bit\n"); + ksft_finished(); +}