I've finally gotten 'cpio' into a shape where it could be useable. This version can archive and extract directories, sockets, FIFOs, devices, symlinks, and regular files. Supported options are -iot, -H FMT (which is a dummy right now). It only writes newc, and could read newc or newcrc. This does NOT implement -d, which essentially is equivalent to mkdir -p $(dirname $FILE) for every file that needs it. Hard links are not supported, though it would be easy to add them given a hash table or something like that. I also have not implemented the "<n> blocks" output on stderr. If desired, I can add it pretty simply. There is one assumption this makes: that the mode of a file, as mode_t, is bitwise equivalent to the mode as defined for the cpio format. This is true of Linux, but is not mandated by POSIX. If it is compiled for a system where that is false, the archives will not be portable.

// Function to display help text

#include "toys.h"

#if !CFG_TOYBOX_HELP
void show_help(void) {;}
#else
#include "generated/help.h"

#undef NEWTOY
#undef OLDTOY
#define NEWTOY(name,opt,flags) help_##name "\0"
#define OLDTOY(name,oldname,opts,flags) "\xff" #oldname "\0"
static char *help_data =
#include "generated/newtoys.h"
;

void show_help(void)
{
  int i = toys.which-toy_list;
  char *s;

  for (;;) {
    s = help_data;
    while (i--) s += strlen(s) + 1;
    // If it's an alias, restart search for real name
    if (*s != 255) break;
    i = toy_find(++s)-toy_list;
  }

  fprintf(toys.exithelp ? stderr : stdout, "%s", s);
}
#endif