src/elfpatch.c

@@ -30,19 +30,6 @@
 #include <fort.h>
 #include <inttypes.h>
 #include <patchelfcrc/crc-output-struct.h>
-#include <byteswap.h>
-
-static const union  {
-	uint8_t data[4];
-	uint32_t val;
-} _endianess_check_union = {{1u, 2u, 3u, 4u}};
-
-enum endianess {
-	END_LITTLE = 0x04030201ul,
-	END_BIG = 0x01020304ul,
-};
-
-#define HOST_ENDIANESS (_endianess_check_union.value)
 
 struct elf_section {
 	GElf_Shdr section_header;
@@ -90,15 +77,14 @@ static uint32_t get_uint32_from_byte_string(const uint8_t *data, bool little_end
 	uint32_t out = 0ul;
 	int i;
 
-	/* Always shift in in big endian format */
 	for (i = 0; i < 4; i++) {
+		if (little_endian)
+			out >>= 8u;
+		else
 			out <<= 8u;
-		out |= (uint32_t)data[i];
-	}
 
-	/* Swap bytes if little endian */
-	if (little_endian)
-		out = bswap_32(out);
+		out |= (((uint32_t)data[i]) << (little_endian ? 24u : 0u));
+	}
 
 	return out;
 }
@@ -110,12 +96,14 @@ static void write_crc_to_byte_array(uint8_t *byte_array, uint32_t crc, uint8_t c
 	if (!byte_array)
 		return;
 
-	if (!little_endian)
-		crc = bswap_32(crc);
-
 	for (i = 0; i < crc_size_bytes; i++) {
-		byte_array[i] = (uint8_t)(crc & 0xFFul);
-		crc >>= 8u;
+		if (little_endian) {
+			byte_array[i] = (uint8_t)(crc & 0xFFul);
+			crc >>= 8u;
+		} else {
+			byte_array[i] = (uint8_t)((crc & 0xFF000000ul) >> 24u);
+			crc <<= 8u;
+		}
 	}
 }
 
@@ -148,14 +136,6 @@ static const char *section_type_to_str(Elf64_Word type)
 		return "INIT_ARRAY";
 	case SHT_FINI_ARRAY:
 		return "FINI_ARRAY";
-	case SHT_PREINIT_ARRAY:
-		return "PREINIT_ARRAY";
-	case SHT_DYNAMIC:
-		return "DYNAMIC";
-	case SHT_ARM_ATTRIBUTES:
-		return "ARM_ATTRIBUTES";
-	case SHT_ARM_PREEMPTMAP:
-		return "ARM_PREEMPTMAP";
 	default:
 		break;
 	}
@@ -167,7 +147,6 @@ static void print_sections(elfpatch_handle_t *ep)
 	SlList *iter;
 	ft_table_t *table;
 	const struct elf_section *section;
-	bool alloc, write, exec;
 
 	ret_if_ep_err(ep);
 
@@ -183,23 +162,15 @@ static void print_sections(elfpatch_handle_t *ep)
 
 	/* Write header */
 	ft_set_cell_prop(table, 0, FT_ANY_COLUMN, FT_CPROP_ROW_TYPE, FT_ROW_HEADER);
-	ft_write_ln(table, "Section", "Type", "ALLOC", "WRITE", "EXEC", "Size", "VMA", "LMA", "File Offset");
+	ft_write_ln(table, "Section", "Type", "Size", "VMA", "LMA", "File Offset");
 
 	for (iter = ep->sections; iter; iter = sl_list_next(iter)) {
 		section = (const struct elf_section *)iter->data;
 		if (!section)
 			continue;
-
-		alloc = !!(section->section_header.sh_flags & SHF_ALLOC);
-		write = !!(section->section_header.sh_flags & SHF_WRITE);
-		exec = !!(section->section_header.sh_flags & SHF_EXECINSTR);
-
-		ft_printf_ln(table, "%s|%s|%s|%s|%s|%lu|%p|%p|%p",
+		ft_printf_ln(table, "%s|%s|%lu|%p|%p|%p",
 			     section->name,
 			     section_type_to_str(section->section_header.sh_type),
-			     alloc ? "x" : "",
-			     write ? "x" : "",
-			     exec ? "x" : "",
 			     section->section_header.sh_size,
 			     (void *)section->section_header.sh_addr,
 			     (void *)section->lma,
@@ -290,12 +261,6 @@ static int elf_patch_read_program_headers(elfpatch_handle_t *ep)
 		return -1;
 	}
 
-	if (header_count == 0) {
-		/* No program headers found. This ELF file is probably not linked */
-		ep->program_headers_count = 0;
-		return 0;
-	}
-
 	ep->program_headers = (GElf_Phdr *)malloc(header_count * sizeof(GElf_Phdr));
 	if (!ep->program_headers) {
 		/* Mem error. Abort. Program will crash eventually */
@@ -341,11 +306,9 @@ static void resolve_section_lmas(elfpatch_handle_t *ep)
 		if (!sec)
 			continue;
 
-		/* By default each sections LMA is assumed to be its LMA as well */
-		sec->lma = (uint64_t)sec->section_header.sh_addr;
-
 		if (sec->section_header.sh_type == SHT_NOBITS) {
 			/* Section does not contain data. It may be allocated but is not loaded. Therefore, LMA=VMA. */
+			sec->lma = (uint64_t)sec->section_header.sh_addr;
 			continue;
 		}