Start working on ELF utils

.gitignore

@@ -40,6 +40,7 @@
 /tests/multiboot2_print1
 /tests/multiboot2_print2
 /tests/test_cmdline
+/tests/test_elf
 /tests/test_multiboot2_helpers
 /tests/test_multiboot2_print
 /tests/test_multiboot2_validation

Makefile.am

@@ -12,6 +12,7 @@ lib_LIBRARIES = libkernaux.a
 TESTS = \
 	examples/printf \
 	examples/printf_va \
+	tests/test_elf \
 	tests/test_printf \
 	tests/test_stdlib
 
@@ -83,6 +84,10 @@ tests_test_cmdline_SOURCES = \
 	$(libkernaux_a_SOURCES) \
 	tests/test_cmdline.c
 
+tests_test_elf_SOURCES = \
+	$(libkernaux_a_SOURCES) \
+	tests/test_elf.c
+
 tests_test_multiboot2_helpers_SOURCES = \
 	$(libkernaux_a_SOURCES) \
 	tests/test_multiboot2_helpers.c

README.md

@@ -26,7 +26,7 @@ API
 * [Multiboot 2 (GRUB 2) information parser](/include/kernaux/multiboot2.h)
 * [Serial console](/include/kernaux/console.h)
 * [Page Frame Allocator](/include/kernaux/pfa.h) *(work in progress)*
-* ELF utils *(planned)*
+* [ELF utils](/include/kernaux/elf.h) *(work in progress)*
 * [Architecture-specific helpers](/include/kernaux/arch/)
 * [printf replacement](/include/kernaux/printf.h) *(work in progress)*
 * [stdlib replacement](/include/kernaux/stdlib.h):

include/kernaux/elf.h

@@ -0,0 +1,136 @@
+#ifndef KERNAUX_INCLUDED_ELF
+#define KERNAUX_INCLUDED_ELF 1
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct KernAux_ELF_Header {
+    unsigned char  magic_0x7F     : 8;
+    unsigned char  magic_E        : 8;
+    unsigned char  magic_L        : 8;
+    unsigned char  magic_F        : 8;
+    unsigned char  bitness        : 8;
+    unsigned char  endianness     : 8;
+    unsigned char  header_version : 8;
+    unsigned char  os_abi         : 8;
+    unsigned long  unused1        : 32;
+    unsigned long  unused2        : 32;
+    unsigned short obj_type       : 16;
+    unsigned short isa            : 16;
+    unsigned long  elf_version    : 32;
+    unsigned long  entrypoint     : 32;
+    unsigned long  prog_table_pos : 32;
+    unsigned long  sect_table_pos : 32;
+    unsigned long  arch_flags     : 32;
+    unsigned short header_size    : 16;
+    unsigned short prog_entr_size : 16;
+    unsigned short prog_entr_num  : 16;
+    unsigned short sect_entr_size : 16;
+    unsigned short sect_entr_num  : 16;
+    unsigned short sect_names_idx : 16;
+}
+__attribute__((packed));
+
+struct KernAux_ELF_ProgramEntry {
+    unsigned long type       : 32;
+    unsigned long offset     : 32;
+    unsigned long virt_addr  : 32;
+    unsigned long phys_addr  : 32;
+    unsigned long file_size  : 32;
+    unsigned long mem_size   : 32;
+    unsigned long flags      : 32;
+    unsigned long align      : 32;
+}
+__attribute__((packed));
+
+struct KernAux_ELF_SectionEntry {
+    unsigned long name        : 32;
+    unsigned long type        : 32;
+    unsigned long flags       : 32;
+    unsigned long vaddr       : 32;
+    unsigned long file_offset : 32;
+    unsigned long file_size   : 32;
+    unsigned long link        : 32;
+    unsigned long info        : 32;
+    unsigned long alignment   : 32;
+    unsigned long ent_size    : 32;
+}
+__attribute__((packed));
+
+struct KernAux_ELF_RelocationEntry {
+    unsigned long virt_addr : 32;
+    unsigned long info      : 32;
+}
+__attribute__((packed));
+
+typedef struct KernAux_ELF_ProgramEntry KernAux_ELF_ProgramTable[];
+
+typedef struct KernAux_ELF_SectionEntry KernAux_ELF_SectionTable[];
+
+typedef struct KernAux_ELF_RelocationEntry KernAux_ELF_RelocationTable[];
+
+inline static bool KernAux_ELF_Header_is_valid(
+    const struct KernAux_ELF_Header *header
+);
+
+bool KernAux_ELF_Header_is_valid(
+    const struct KernAux_ELF_Header *const header
+) {
+    if (!(
+        header->magic_0x7F     == 0x7F &&
+        header->magic_E        == 'E'  &&
+        header->magic_L        == 'L'  &&
+        header->magic_F        == 'F'  &&
+        header->header_version == 1    &&
+        header->elf_version    == 1
+    )) {
+        return false;
+    }
+
+    if (!(
+        header->bitness == 1 || // 32 bit
+        header->bitness == 2    // 64 bit
+    )) {
+        return false;
+    }
+
+    if (!(
+        header->endianness == 1 || // Little endian
+        header->endianness == 2    // Big endian
+    )) {
+        return false;
+    }
+
+    if (!(
+        header->os_abi >= 0    &&
+        header->os_abi <= 0x12 &&
+        header->os_abi != 0x05
+    )) {
+        return false;
+    }
+
+    if (!(
+        header->obj_type == 0x00   || // NONE
+        header->obj_type == 0x01   || // REL
+        header->obj_type == 0x02   || // EXEC
+        header->obj_type == 0x03   || // DYN
+        header->obj_type == 0x04   || // CORE
+        header->obj_type == 0xFE00 || // LOOS
+        header->obj_type == 0xFEFF || // HIOS
+        header->obj_type == 0xFF00 || // LOPROC
+        header->obj_type == 0xFFFF    // HIPROC
+    )) {
+        return false;
+    }
+
+    return true;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

tests/test_elf.c

@@ -0,0 +1,29 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <kernaux/elf.h>
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#define BUFFER_SIZE (1024 * 1024)
+
+int main(int argc, char **argv)
+{
+    assert(argc >= 1);
+
+    FILE *const fd = fopen(argv[0], "r");
+    assert(fd);
+
+    unsigned char buffer[BUFFER_SIZE];
+    const size_t size = fread(buffer, sizeof(unsigned char), BUFFER_SIZE, fd);
+    assert(size > 0);
+
+    assert(KernAux_ELF_Header_is_valid(buffer));
+
+    fclose(fd);
+
+    return 0;
+}