Remove debugging printfs

man/patchelfcrc.1.md

@@ -136,4 +136,4 @@ The output sections start and end are checked for the given magic numbers in ord
 The memory is interpreted as *little endian* and the CRC calculation granularity is a 32 bit *word*.
 
 # BUGS
-Currently, reversed CRC algorithms are not implemented.
+None

src/crc.c

@@ -34,13 +34,26 @@ int crc_len_from_poly(uint64_t polynomial)
 	return pos;
 }
 
+static uint32_t reverse_short_poly(uint32_t poly, uint8_t len)
+{
+	uint8_t i;
+	uint32_t ret = 0ul;
+
+	for (i = 0; i < len; i++) {
+		ret <<= 1;
+		ret |= (poly & 1u);
+		poly >>= 1;
+	}
+
+	return ret;
+}
+
 static uint64_t shorten_polynomial(uint64_t poly)
 {
 	int i;
-
-	for (i = 31; i <= 0; i--) {
-		if (poly & (1 << i)) {
-			poly &= ~(1<<i);
+	for (i = 32; i >= 0; i--) {
+		if (poly & ((uint64_t)1ull << i)) {
+			poly &= ~((uint64_t)1ull<<i);
 			break;
 		}
 	}
@@ -55,14 +68,22 @@ static void internal_push_byte(struct crc_calc *crc, const uint8_t *data, size_t
 
 	crc_val = crc->crc_val;
 
-	for (i = 0; i < len; i++, data++) {
-		crc_val = ((crc_val << 8) & crc->crc_mask) ^ crc->table[((crc_val >> (crc->crc_length-8u)) & 0xff) ^ *data];
+	if (crc->settings.rev) {
+		for (i = 0; i < len; i++, data++) {
+			crc_val = (crc_val >> 8) ^ crc->table[((crc_val & 0xFF) ^ *data)];
+		}
+	} else {
+		/* Non reversed algo */
+		for (i = 0; i < len; i++, data++) {
+			crc_val = ((crc_val << 8) & crc->crc_mask) ^
+				crc->table[((crc_val >> (crc->crc_length-8u)) & 0xff) ^ *data];
+		}
 	}
 
 	crc->crc_val = crc_val;
 }
 
-static void fill_crc_table(struct crc_calc *crc)
+static void fill_crc_table_non_reversed(struct crc_calc *crc)
 {
 	uint32_t input;
 	uint32_t crc_reg;
@@ -86,10 +107,44 @@ static void fill_crc_table(struct crc_calc *crc)
 				crc_reg <<= 1;
 			}
 		}
-		crc->table[input] = crc_reg;
+		crc->table[input] = crc_reg & crc->crc_mask;
 	}
 }
 
+static void fill_crc_table_reversed(struct crc_calc *crc)
+{
+	uint32_t input;
+	uint32_t crc_reg;
+	uint32_t short_poly;
+	int i;
+
+	short_poly = (uint32_t)shorten_polynomial(crc->settings.polynomial);
+	short_poly = reverse_short_poly(short_poly, crc->crc_length);
+
+	for (input = 0; input <= 255u; input++) {
+		crc_reg = (uint32_t)input;
+		for (i = 0; i < 8; i++) {
+			/* Check LSB for reversed CRC shifting */
+			if (crc_reg & 1u) {
+				crc_reg >>= 1;
+				crc_reg ^= short_poly;
+			} else {
+				crc_reg >>= 1;
+			}
+		}
+		crc->table[input] = crc_reg & crc->crc_mask;
+	}
+
+}
+
+static void fill_crc_table(struct crc_calc *crc)
+{
+	if (crc->settings.rev)
+		fill_crc_table_reversed(crc);
+	else
+		fill_crc_table_non_reversed(crc);
+}
+
 void crc_init(struct crc_calc *crc, const struct crc_settings *settings)
 {
 	uint32_t i;

src/elfpatch.c

@@ -55,16 +55,16 @@ struct elfpatch {
 #define is_elfpatch_struct(x) ((x) && (x)->magic == (ELFPATCH_MAGIC))
 
 #define ret_if_ep_err(ep) do { \
-	if (!is_elfpatch_struct((ep))) { \
-	return; \
-	} \
-	} while(0)
+		if (!is_elfpatch_struct((ep))) { \
+			return; \
+		} \
+	} while (0)
 
 #define ret_val_if_ep_err(ep, val) do { \
-	if (!is_elfpatch_struct((ep))) { \
-	return (val); \
-	} \
-	} while(0)
+		if (!is_elfpatch_struct((ep))) { \
+			return val; \
+		} \
+	} while (0)
 
 /**
  * @brief Convert a series of 4 bytes into a uint32_t dpending on endianess
@@ -197,7 +197,7 @@ static SlList *elf_patch_get_sections(elfpatch_handle_t *ep)
 		sl_list_free_full(ret, (void (*)(void *))free_elf_section_element);
 	ep->sections = NULL;
 
-	if (elf_getshdrstrndx (ep->elf , &shstrndx) != 0) {
+	if (elf_getshdrstrndx(ep->elf, &shstrndx) != 0) {
 		print_err("ELF error: %s\n", elf_errmsg(-1));
 		goto ret_free_section_list;
 	}
@@ -218,9 +218,10 @@ static SlList *elf_patch_get_sections(elfpatch_handle_t *ep)
 		sec->lma = (uint64_t)sec->section_header.sh_addr;
 
 		name = elf_strptr(ep->elf, shstrndx, sec->section_header.sh_name);
-		if (name) {
+
+		if (name)
 			sec->name = strdup(name);
-		}
+
 		ret = sl_list_append(ret, sec);
 	}
 
@@ -431,15 +432,13 @@ elfpatch_handle_t *elf_patch_open(const char *path, bool readonly, bool expect_l
 		switch (ident[5]) {
 		case 1:
 			print_debug("ELF Endianess: little\n");
-			if (!expect_little_endian) {
+			if (!expect_little_endian)
 				print_err("Big endian format expected. File is little endian. Double check settings!\n");
-			}
 			break;
 		case 2:
 			print_debug("ELF Endianess: big\n");
-			if (expect_little_endian) {
+			if (expect_little_endian)
 				print_err("Little endian format expected. File is big endian. Double check settings!\n");
-			}
 			break;
 		default:
 			print_err("Cannot determine endianess of ELF file. EI_DATA is: %d\n", ident[5]);
@@ -454,9 +453,8 @@ close_elf:
 		ep->elf = NULL;
 	}
 close_fd:
-	if (ep->fd > 0) {
+	if (ep->fd > 0)
 		close(ep->fd);
-	}
 free_struct:
 	free(ep);
 	ep = NULL;
@@ -491,14 +489,14 @@ int elf_patch_check_for_section(elfpatch_handle_t *ep, const char *section)
 	return ret;
 }
 
-static size_t translate_index(size_t index, enum granularity granularity, bool little_endian)
+static size_t translate_index(size_t index, enum granularity granularity, bool little_endian, bool reversed)
 {
 	size_t word_idx;
 	size_t part_idx;
 	size_t d_index;
 	size_t gran_in_bytes;
 
-	if (!little_endian || granularity == GRANULARITY_BYTE)
+	if ((!little_endian && !reversed) || (little_endian && reversed) || granularity == GRANULARITY_BYTE)
 		return index;
 
 	gran_in_bytes = (size_t)granularity / 8u;
@@ -548,8 +546,9 @@ int elf_patch_compute_crc_over_section(elfpatch_handle_t *ep, const char *sectio
 		return -2;
 	}
 
-	/* If big endian or granularity is byte, simply compute CRC. No reordering is necessary */
-	if (!little_endian || granularity == GRANULARITY_BYTE) {
+	/* If big endian for non reversed / little endian for reversed or granularity is byte, simply compute CRC. No reordering is necessary */
+	if ((!little_endian && !crc->settings.rev) || (little_endian && crc->settings.rev) ||
+			granularity == GRANULARITY_BYTE) {
 		crc_push_bytes(crc, data->d_buf, data->d_size);
 	} else {
 		/* Little endian case with > byte sized chunks */
@@ -561,14 +560,17 @@ int elf_patch_compute_crc_over_section(elfpatch_handle_t *ep, const char *sectio
 				  section, padding_count);
 		}
 
-		for (idx = 0; idx < data->d_size; idx++) {
-			crc_push_byte(crc, ((char *)data->d_buf)[translate_index(idx, granularity, little_endian)]);
-		}
+		for (idx = 0; idx < data->d_size; idx++)
+			crc_push_byte(crc,
+				      ((char *)data->d_buf)[
+					translate_index(idx, granularity,
+						little_endian,
+						crc->settings.rev)
+					]);
 
 		/* Pad with zeroes */
-		for (idx = 0; idx < padding_count; idx++) {
+		for (idx = 0; idx < padding_count; idx++)
 			crc_push_byte(crc, 0x00);
-		}
 	}
 
 	return 0;
@@ -711,8 +713,8 @@ int elf_patch_write_crcs_to_section(elfpatch_handle_t *ep, const char *output_se
 
 	print_debug("Single CRC requires %u bytes.\n", (unsigned int)crc_size_bytes);
 
-	needed_space = calculate_needed_space_for_crcs(format, crc_data->elf_bits, check_start_magic, check_end_magic, crc_size_bytes,
-						       crc_count);
+	needed_space = calculate_needed_space_for_crcs(format, crc_data->elf_bits, check_start_magic,
+		check_end_magic, crc_size_bytes, crc_count);
 
 	print_debug("Required space for %zu CRCs%s: %zu (available: %zu)\n",
 		    crc_count,
@@ -782,11 +784,10 @@ int elf_patch_write_crcs_to_section(elfpatch_handle_t *ep, const char *output_se
 		crc_64bit.length = 0ull;
 		crc_64bit.start_address = 0ull;
 
-		if (crc_data->elf_bits == 32) {
+		if (crc_data->elf_bits == 32)
 			memcpy(sec_bytes, &crc_32bit, sizeof(crc_32bit));
-		} else {
+		else
 			memcpy(sec_bytes, &crc_64bit, sizeof(crc_64bit));
-		}
 	}
 
 	/* Flag section data as invalid to trigger rewrite.
@@ -808,9 +809,8 @@ void elf_patch_close_and_free(elfpatch_handle_t *ep)
 		if (ep->readonly) {
 			print_debug("DRY RUN: File will not be updated\n");
 		} else {
-			if (elf_update(ep->elf, ELF_C_WRITE) < 0) {
+			if (elf_update(ep->elf, ELF_C_WRITE) < 0)
 				print_err("Error writing ELF file: %s\n", elf_errmsg(-1));
-			}
 		}
 	}
 

src/main.c

@@ -108,11 +108,11 @@ static error_t parse_opt(int key, char *arg, struct argp_state *state)
 		/* Polyniomial */
 		args->crc.polynomial = strtoull(arg, &endptr, 0);
 		if (endptr == arg) {
-			if ((looked_up_crc = lookup_named_crc(arg))) {
+			looked_up_crc = lookup_named_crc(arg);
+			if (looked_up_crc)
 				memcpy(&args->crc, &looked_up_crc->settings, sizeof(struct crc_settings));
-			} else {
+			else
 				argp_error(state, "Error parsing polynomial: %s\n", arg);
-			}
 		}
 		break;
 	case 'l':
@@ -261,28 +261,22 @@ static void print_verbose_start_info(const struct command_line_options *cmd_opts
 		print_debug("CRC length: %d\n", crc_len_from_poly(cmd_opts->crc.polynomial));
 	}
 
-	if (cmd_opts->elf_path) {
+	if (cmd_opts->elf_path)
 		print_debug("ELF file: %s\n", cmd_opts->elf_path);
-	}
 
-	if (cmd_opts->output_section) {
+	if (cmd_opts->output_section)
 		print_debug("Output section: %s\n", cmd_opts->output_section);
-	}
 
-	if (cmd_opts->export_xml) {
+	if (cmd_opts->export_xml)
 		print_debug("Export CRCs to '%s'\n", cmd_opts->export_xml);
-	}
 
-	if (cmd_opts->import_xml) {
+	if (cmd_opts->import_xml)
 		print_debug("Import CRCs from '%s'\n", cmd_opts->import_xml);
-	}
 
 	if (cmd_opts->section_list) {
-		for (list_iter = cmd_opts->section_list, i = 1; list_iter; list_iter = sl_list_next(list_iter), i++) {
+		for (list_iter = cmd_opts->section_list, i = 1; list_iter; list_iter = sl_list_next(list_iter), i++)
 			print_debug("Input section [%d]: \"%s\"\n", i, (const char *)list_iter->data);
-		}
 	}
-
 }
 
 static void free_cmd_args(struct command_line_options *opts)
@@ -322,6 +316,7 @@ static int check_all_sections_present(elfpatch_handle_t *ep, SlList *list)
 		sec_name = (const char *)iter->data;
 		if (!sec_name)
 			continue;
+
 		if (elf_patch_check_for_section(ep, sec_name)) {
 			print_err("Cannot find section '%s'\n", sec_name);
 			ret = -2;
@@ -340,7 +335,8 @@ static int check_all_sections_present(elfpatch_handle_t *ep, SlList *list)
  * @param opts Command line options. Used for CRC generation
  * @return CRC data
  */
-static struct crc_import_data *compute_crcs(elfpatch_handle_t *ep, SlList *list, const struct command_line_options *opts)
+static struct crc_import_data *compute_crcs(elfpatch_handle_t *ep, SlList *list,
+	const struct command_line_options *opts)
 {
 	SlList *iter;
 	const char *sec_name;
@@ -423,6 +419,7 @@ int main(int argc, char **argv)
 
 	prepare_default_opts(&cmd_opts);
 	parse_cmdline_options(&argc, &argv, &cmd_opts);
+
 	if (cmd_opts.print_xsd) {
 		xml_print_xsd();
 		goto free_cmds;
@@ -430,6 +427,7 @@ int main(int argc, char **argv)
 
 	if (cmd_opts.verbose || cmd_opts.dry_run)
 		reporting_enable_verbose();
+
 	print_verbose_start_info(&cmd_opts);
 
 	if (cmd_opts.list) {
@@ -448,19 +446,11 @@ int main(int argc, char **argv)
 		return -2;
 	}
 
-	if (cmd_opts.use_vma && cmd_opts.format != FORMAT_STRUCT) {
+	if (cmd_opts.use_vma && cmd_opts.format != FORMAT_STRUCT)
 		print_warn("--use-vma option only has an effect when exporting as struct output.\n");
-	}
 
-	if (!cmd_opts.output_section && cmd_opts.export_xml == NULL) {
+	if (!cmd_opts.output_section && cmd_opts.export_xml == NULL)
 		print_err("No output section / XML export specified. Will continue but not create any output\n");
-	}
-
-	/* Do error printing if using a reversed polynomial. It is not implemented yet! */
-	if (cmd_opts.crc.rev) {
-		print_err("Reversed polynomials are not supported yet\nExiting...\n");
-		goto free_cmds;
-	}
 
 	/* Prepare libelf for use with the latest ELF version */
 	elf_version(EV_CURRENT);
@@ -481,13 +471,11 @@ int main(int argc, char **argv)
 
 		/* Compute CRCs over sections */
 		crc_data = compute_crcs(ep, cmd_opts.section_list, &cmd_opts);
-		if (!crc_data) {
+		if (!crc_data)
 			goto ret_close_elf;
-		}
 
-		if (reporting_get_verbosity()) {
+		if (reporting_get_verbosity())
 			print_crcs(crc_data);
-		}
 	} else {
 		crc_data = xml_import_from_file(cmd_opts.import_xml);
 	}

src/named_crcs.c

@@ -28,7 +28,7 @@
 		.xor = outxor, \
 		.start_value = init, \
 		.rev = reverse \
-}}
+} }
 
 const struct named_crc predefined_crc_table[] = {
 	NAMED_CRC("crc-8", 0x107, false, 0x00, 0x00),
@@ -70,7 +70,7 @@ const struct named_crc predefined_crc_table[] = {
 	NAMED_CRC("jamcrc", 0x104C11DB7, true, 0xFFFFFFFF, 0x00000000),
 	NAMED_CRC("xfer", 0x1000000AF, false, 0x00000000, 0x00000000),
 	/* SENTINEL */
-	{.name = NULL, .settings = {0, 0, 0, false}},
+	{ .name = NULL, .settings = {0, 0, 0, false} },
 };
 
 const struct named_crc *reverse_lookup_named_crc(const struct crc_settings *settings)
@@ -110,19 +110,26 @@ void list_predefined_crcs(void)
 {
 	ft_table_t *table;
 	const struct named_crc *iter;
+	struct crc_calc crc;
 
 	table = ft_create_table();
 
 	ft_set_cell_prop(table, 0, FT_ANY_COLUMN, FT_CPROP_ROW_TYPE, FT_ROW_HEADER);
-	ft_write_ln(table, "Name", "Polynomial", "Reversed", "Start Value", "Output XOR");
+	ft_write_ln(table, "Name", "Polynomial", "Reversed", "Start Value", "Output XOR", "Test Value");
 
 	for (iter = predefined_crc_table; iter->name; iter++) {
-		ft_printf_ln(table, "%s|0x%lx|%s|0x%x|0x%x",
+		crc_init(&crc, &iter->settings);
+		/* Calculate the test value */
+		crc_push_bytes(&crc, (const uint8_t *)"123456789", 9);
+		crc_finish_calc(&crc);
+		ft_printf_ln(table, "%s|0x%lx|%s|0x%x|0x%x|0x%x",
 			     iter->name,
 			     iter->settings.polynomial,
 			     iter->settings.rev ? "yes" : "no",
 			     iter->settings.start_value,
-			     iter->settings.xor);
+			     iter->settings.xor,
+			     crc_get_value(&crc));
+		crc_destroy(&crc);
 	}
 
 	printf("%s\n", ft_to_string(table));

src/xml.c

@@ -30,9 +30,8 @@ int xml_write_crcs_to_file(const char *path, const struct crc_import_data *crc_d
 	const struct crc_entry *entry;
 	size_t index;
 
-	if (!path || !crc_data) {
+	if (!path || !crc_data)
 		return -1000;
-	}
 
 	writer = xmlNewTextWriterFilename(path, 0);
 	if (!writer) {
@@ -67,7 +66,9 @@ int xml_write_crcs_to_file(const char *path, const struct crc_import_data *crc_d
 	xmlTextWriterStartElement(writer, BAD_CAST "sections");
 
 	/* Output all section CRCs */
-	for (entry_iter = crc_data->crc_entries, index = 0u; entry_iter; entry_iter = sl_list_next(entry_iter), index++) {
+	for (entry_iter = crc_data->crc_entries, index = 0u;
+	entry_iter;
+	entry_iter = sl_list_next(entry_iter), index++) {
 		entry = (const struct crc_entry *)entry_iter->data;
 		xmlTextWriterStartElement(writer, BAD_CAST "crc");
 		xmlTextWriterWriteFormatAttribute(writer, BAD_CAST "name", "%s", entry->name);
@@ -222,7 +223,8 @@ static int convert_number_string_to_uint(const char *data, uint64_t *output)
  * @return 0 if successful
  * @return negative in case of an error
  */
-static int get_uint64_from_xpath_content(const char *xpath, xmlXPathContextPtr xpath_ctx, uint64_t *output, bool required)
+static int get_uint64_from_xpath_content(const char *xpath, xmlXPathContextPtr xpath_ctx,
+						uint64_t *output, bool required)
 {
 	const char *data;
 	int ret = -1;
@@ -245,7 +247,8 @@ static int get_uint64_from_xpath_content(const char *xpath, xmlXPathContextPtr x
  * @return 0 if successful
  * @return negative in case of an error
  */
-static int get_uint32_from_xpath_content(const char *xpath, xmlXPathContextPtr xpath_ctx, uint32_t *output, bool required)
+static int get_uint32_from_xpath_content(const char *xpath, xmlXPathContextPtr xpath_ctx,
+						uint32_t *output, bool required)
 {
 	const char *data;
 	uint64_t tmp;
@@ -359,10 +362,10 @@ struct crc_import_data *xml_import_from_file(const char *path)
 		print_err("Error reading XML file: %s\n", path);
 		goto ret_none;
 	}
+
 	root_node = xmlDocGetRootElement(doc);
-	if (!root_node) {
+	if (!root_node)
 		goto ret_close_doc;
-	}
 
 	/* Validate the document */
 	if (!validate_xml_doc(doc)) {
@@ -372,9 +375,8 @@ struct crc_import_data *xml_import_from_file(const char *path)
 
 	/* Get xpath context */
 	xpath_ctx = xmlXPathNewContext(doc);
-	if (!xpath_ctx) {
+	if (!xpath_ctx)
 		goto ret_close_doc;
-	}
 
 	/* Get the version number and print error in case of incompatibility. Continue either way */
 	cptr = (char *)xmlGetProp(root_node, BAD_CAST "version");