NationalSecurityAgency/ghidra · error

%s: error: too many @-files encountered

Error message

%s: error: too many @-files encountered

What it means

In libiberty's buildargv/expandargv-style argument processing (argv.c), command-line tokens of the form @file are expanded by reading the named response file and inserting its contents as arguments. A counter (iteration_limit, initialized to 2000) bounds how many @-files are processed to stop infinite recursion (e.g. @a includes @a, or a cycle). When the counter hits zero the program prints this error and calls xexit(1).

Source

Thrown at GPL/DemanglerGnu/src/demangler_gnu_v2_24/c/argv.c:406

      /* The number of characters in the response file, when actually
	 read.  */
      size_t len;
      /* A dynamically allocated buffer used to hold options read from a
	 response file.  */
      char *buffer;
      /* Dynamically allocated storage for the options read from the
	 response file.  */
      char **file_argv;
      /* The number of options read from the response file, if any.  */
      size_t file_argc;
      /* We are only interested in options of the form "@file".  */
      filename = (*argvp)[i];
      if (filename[0] != '@')
	continue;
      /* If we have iterated too many times then stop.  */
      if (-- iteration_limit == 0)
	{
	  fprintf (stderr, "%s: error: too many @-files encountered\n", (*argvp)[0]);
	  xexit (1);
	}
      /* Read the contents of the file.  */
      f = fopen (++filename, "r");
      if (!f)
	continue;
      if (fseek (f, 0L, SEEK_END) == -1)
	goto error;
      pos = ftell (f);
      if (pos == -1)
	goto error;
      if (fseek (f, 0L, SEEK_SET) == -1)
	goto error;
      buffer = (char *) xmalloc (pos * sizeof (char) + 1);
      len = fread (buffer, sizeof (char), pos, f);
      if (len != (size_t) pos
	  /* On Windows, fread may return a value smaller than POS,
	     due to CR/LF->CR translation when reading text files.

View on GitHub (pinned to d5f144c24d)

Solutions

  1. Check response files for self-references or mutual cycles (grep for the file's own name inside it).
  2. Regenerate the response file so it lists only real arguments, never @-references back into itself.
  3. Remove the @file indirection and pass arguments directly to confirm the cycle is the cause.
  4. Audit build scripts/templates that produce @-files to exclude the response file path from its own contents.

Example fix

# before: build/link.args contains a line '@link.args' (self-reference)
clang @build/link.args main.c

# after: regenerate build/link.args without self-inclusion
# (e.g. exclude the args file itself from the glob that writes it)
clang @build/link.args main.c
Defensive patterns

Strategy: validation

Validate before calling

// Validate response files for self-reference before invoking the tool
#include <stdio.h>
#include <string.h>
int self_references(const char *file) {
    /* returns 1 if 'file' contains an @-ref to itself */
    FILE *f = fopen(file, "r"); char line[4096]; int found = 0;
    if (!f) return 0;
    while (fgets(line, sizeof line, f))
        if (strstr(line, file)) { found = 1; break; }
    fclose(f); return found;
}

Type guard

// detect a cycle in @-file references before passing to the tool
bool hasResponseFileCycle(const std::vector<std::string>& files);

Try / catch

// This is a CLI invocation error that calls xexit(1); it cannot be caught.
// Capture child stderr and non-zero exit code in the calling process:
int rc = run_child({"clang", "@build/args", "main.c"});
if (rc != 0 && stderr_contains("too many @-files")) {
    report("response file cycle detected; regenerating @build/args without self-reference");
}

Prevention

When it happens

Trigger: Supplying a @file argument whose response file(s) transitively reference enough @-files to exhaust the 2000-deep limit, typically via a circular chain (file @a contains '@a') or a very deep, self-referential include graph.

Common situations: A generated response file accidentally includes itself (common with build tools that emit @file from a glob that contains the response file); a circular reference between two response files; an extremely large, deliberately nested set of @-files. This is a build/CLI invocation problem, not a runtime data problem.

Related errors

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/17453d31fe858f73. Report an issue: GitHub.