Usage: %s target-str, arch, mach, disassembly base-addr (for

Q: What causes "Usage: %s target-str, arch, mach, disassembly base-addr (for rel offsets instrs), full-path to Little and Big Elfs, big/little ascii-byte-string up to %d chars\n" in NationalSecurityAgency/ghidra?

Supply all 7 arguments in order: target arch mach base-addr little-elf big-elf bytestring.

Error message

Usage: %s target-str, arch, mach, disassembly base-addr (for rel offsets instrs), full-path to Little and Big Elfs, big/little ascii-byte-string up to %d chars\n

What it means

GnuDisassembler (gdis) usage error. main() requires at least 8 argv elements: program name, target-str, arch, mach, disassembly base-addr, path to little-endian ELF, path to big-endian ELF, and an ascii hex byte-string. When argc < 8 it prints the Usage line to stderr, lists supported arch/mach targets and all BFD-known architectures, then continues (does not exit at this point).

Source

Thrown at GPL/GnuDisassembler/src/gdis/c/disasm_1.c:240

int main(int argc, char* argv[]){
	struct disassemble_info DI;
	enum bfd_architecture arch;
	struct bfd_arch_info ai;
	unsigned long mach;
	enum bfd_endian endian;
	unsigned int end;
	bfd_vma offset;
	disassembler_ftype disassemble_fn;
	char *target = default_target;
	bfd *bfdfile;
	unsigned long a,m;
	char* byteString;
	char elf_file_location[MAX_ELF_FILE_PATH_LEN];
	char arch_str[256];
	char mach_str[256];

	if ( argc < 8) {
		fprintf(stderr, "Usage: %s target-str, arch, mach, disassembly base-addr (for rel offsets instrs), full-path to Little and Big Elfs, big/little ascii-byte-string up to %d chars\n", argv[0], MAX_ASCII_CHAR_BYTE_STRING);
		listSupportedArchMachTargets();
		const char** archList = bfd_arch_list();
		const bfd_arch_info_type* ait;
		while(*archList != NULL){
			printf("checking against architecture: %s.\n", *archList);
			ait = NULL;
			ait = bfd_scan_arch(*archList);
			if(ait != NULL){
				printf("archname: %s arch: 0x%08X, mach: 0x%08lX.\n", ait->arch_name, ait->arch, ait->mach);
			}
			archList++;
		}
		return(1);
	}

	end = 0x00000000;
	endian = (enum bfd_endian) 0x00;
	mach = 0x00000000;

View on GitHub (pinned to d5f144c24d)

Solutions

Supply all 7 arguments in order: target arch mach base-addr little-elf big-elf bytestring.
Run with no/insufficient args intentionally to dump the supported arch/mach list, then re-invoke correctly.
Wrap the binary in a script that validates argc >= 8 before exec.
Check the two ELF file paths exist and the byte-string is within MAX_ASCII_CHAR_BYTE_STRING.

Example fix

// before
$ gdis i386:x86-64

// after (target arch mach base-addr little-elf big-elf bytes)
$ gdis "i386:x86-64" "i386" "x86-64" 0x400000 ./prog.le ./prog.be 90909090

Defensive patterns

Strategy: validation

Validate before calling

if (argc < 8) {
  fprintf(stderr, "gdis needs 7 args: target arch mach base-addr le-elf be-elf bytes\n");
  return 2;
}

Prevention

Wrap gdis in a launcher that checks argc >= 8.
Validate file paths and byte-string length before exec.
Run with insufficient args once to capture the supported arch list.

When it happens

Trigger: Invoking the gdis binary with fewer than 7 user arguments (argc < 8). E.g. calling `gdis <target>` without arch, mach, base-addr, and both ELF paths.

Common situations: First-time use without reading the argument contract; a wrapper/IDE launcher dropping trailing arguments; missing the dual (little + big endian) ELF path requirement.

Related errors

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/4784d5eb0742059b. Report an issue: GitHub.