void rproc_coredump_using_sections()

in remoteproc_coredump.c [343:468]

• 90 lines of code
• 8 McCabe index (conditional complexity)

void rproc_coredump_using_sections(struct rproc *rproc)
{
	struct rproc_dump_segment *segment;
	void *shdr;
	void *ehdr;
	size_t data_size;
	size_t strtbl_size = 0;
	size_t strtbl_index = 1;
	size_t offset;
	void *data;
	u8 class = rproc->elf_class;
	int shnum;
	struct rproc_coredump_state dump_state;
	unsigned int dump_conf = rproc->dump_conf;
	char *str_tbl = "STR_TBL";

	if (list_empty(&rproc->dump_segments) ||
	    dump_conf == RPROC_COREDUMP_DISABLED)
		return;

	if (class == ELFCLASSNONE) {
		dev_err(&rproc->dev, "Elf class is not set\n");
		return;
	}

	/*
	 * We allocate two extra section headers. The first one is null.
	 * Second section header is for the string table. Also space is
	 * allocated for string table.
	 */
	data_size = elf_size_of_hdr(class) + 2 * elf_size_of_shdr(class);
	shnum = 2;

	/* the extra byte is for the null character at index 0 */
	strtbl_size += strlen(str_tbl) + 2;

	list_for_each_entry(segment, &rproc->dump_segments, node) {
		data_size += elf_size_of_shdr(class);
		strtbl_size += strlen(segment->priv) + 1;
		if (dump_conf == RPROC_COREDUMP_ENABLED)
			data_size += segment->size;
		shnum++;
	}

	data_size += strtbl_size;

	data = vmalloc(data_size);
	if (!data)
		return;

	ehdr = data;
	memset(ehdr, 0, elf_size_of_hdr(class));
	/* e_ident field is common for both elf32 and elf64 */
	elf_hdr_init_ident(ehdr, class);

	elf_hdr_set_e_type(class, ehdr, ET_CORE);
	elf_hdr_set_e_machine(class, ehdr, rproc->elf_machine);
	elf_hdr_set_e_version(class, ehdr, EV_CURRENT);
	elf_hdr_set_e_entry(class, ehdr, rproc->bootaddr);
	elf_hdr_set_e_shoff(class, ehdr, elf_size_of_hdr(class));
	elf_hdr_set_e_ehsize(class, ehdr, elf_size_of_hdr(class));
	elf_hdr_set_e_shentsize(class, ehdr, elf_size_of_shdr(class));
	elf_hdr_set_e_shnum(class, ehdr, shnum);
	elf_hdr_set_e_shstrndx(class, ehdr, 1);

	/*
	 * The zeroth index of the section header is reserved and is rarely used.
	 * Set the section header as null (SHN_UNDEF) and move to the next one.
	 */
	shdr = data + elf_hdr_get_e_shoff(class, ehdr);
	memset(shdr, 0, elf_size_of_shdr(class));
	shdr += elf_size_of_shdr(class);

	/* Initialize the string table. */
	offset = elf_hdr_get_e_shoff(class, ehdr) +
		 elf_size_of_shdr(class) * elf_hdr_get_e_shnum(class, ehdr);
	memset(data + offset, 0, strtbl_size);

	/* Fill in the string table section header. */
	memset(shdr, 0, elf_size_of_shdr(class));
	elf_shdr_set_sh_type(class, shdr, SHT_STRTAB);
	elf_shdr_set_sh_offset(class, shdr, offset);
	elf_shdr_set_sh_size(class, shdr, strtbl_size);
	elf_shdr_set_sh_entsize(class, shdr, 0);
	elf_shdr_set_sh_flags(class, shdr, 0);
	elf_shdr_set_sh_name(class, shdr, elf_strtbl_add(str_tbl, ehdr, class, &strtbl_index));
	offset += elf_shdr_get_sh_size(class, shdr);
	shdr += elf_size_of_shdr(class);

	list_for_each_entry(segment, &rproc->dump_segments, node) {
		memset(shdr, 0, elf_size_of_shdr(class));
		elf_shdr_set_sh_type(class, shdr, SHT_PROGBITS);
		elf_shdr_set_sh_offset(class, shdr, offset);
		elf_shdr_set_sh_addr(class, shdr, segment->da);
		elf_shdr_set_sh_size(class, shdr, segment->size);
		elf_shdr_set_sh_entsize(class, shdr, 0);
		elf_shdr_set_sh_flags(class, shdr, SHF_WRITE);
		elf_shdr_set_sh_name(class, shdr,
				     elf_strtbl_add(segment->priv, ehdr, class, &strtbl_index));

		/* No need to copy segments for inline dumps */
		if (dump_conf == RPROC_COREDUMP_ENABLED)
			rproc_copy_segment(rproc, data + offset, segment, 0,
					   segment->size);
		offset += elf_shdr_get_sh_size(class, shdr);
		shdr += elf_size_of_shdr(class);
	}

	if (dump_conf == RPROC_COREDUMP_ENABLED) {
		dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
		return;
	}

	/* Initialize the dump state struct to be used by rproc_coredump_read */
	dump_state.rproc = rproc;
	dump_state.header = data;
	init_completion(&dump_state.dump_done);

	dev_coredumpm(&rproc->dev, NULL, &dump_state, data_size, GFP_KERNEL,
		      rproc_coredump_read, rproc_coredump_free);

	/* Wait until the dump is read and free is called. Data is freed
	 * by devcoredump framework automatically after 5 minutes.
	 */
	wait_for_completion(&dump_state.dump_done);
}