/* error.c : utility for looking up errno error numbers */
/* original version: 2006 June 27
 * 2006 June 29 -- version 1.04
 * contributers: Jon Mayo <jon.mayo@acm.org>
 * No copyright claimed -- Public Domain */

/* TODO: convert error strings into error numbers/names */

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define T(x) if(e==(x)) return #x

static const char **id_lookup_table;
static unsigned id_max;

static const char *
err_id(int e)
{
#ifdef EPERM
	T(EPERM);
#endif
#ifdef ENOENT
	T(ENOENT);
#endif
#ifdef ESRCH
	T(ESRCH);
#endif
#ifdef EINTR
	T(EINTR);
#endif
#ifdef EIO
	T(EIO);
#endif
#ifdef ENXIO
	T(ENXIO);
#endif
#ifdef E2BIG
	T(E2BIG);
#endif
#ifdef ENOEXEC
	T(ENOEXEC);
#endif
#ifdef EBADF
	T(EBADF);
#endif
#ifdef ECHILD
	T(ECHILD);
#endif
#ifdef EAGAIN
	T(EAGAIN);
#endif
#ifdef ENOMEM
	T(ENOMEM);
#endif
#ifdef EACCES
	T(EACCES);
#endif
#ifdef EFAULT
	T(EFAULT);
#endif
#ifdef ENOTBLK
	T(ENOTBLK);
#endif
#ifdef EBUSY
	T(EBUSY);
#endif
#ifdef EEXIST
	T(EEXIST);
#endif
#ifdef EXDEV
	T(EXDEV);
#endif
#ifdef ENODEV
	T(ENODEV);
#endif
#ifdef ENOTDIR
	T(ENOTDIR);
#endif
#ifdef EISDIR
	T(EISDIR);
#endif
#ifdef EINVAL
	T(EINVAL);
#endif
#ifdef ENFILE
	T(ENFILE);
#endif
#ifdef EMFILE
	T(EMFILE);
#endif
#ifdef ENOTTY
	T(ENOTTY);
#endif
#ifdef ETXTBSY
	T(ETXTBSY);
#endif
#ifdef EFBIG
	T(EFBIG);
#endif
#ifdef ENOSPC
	T(ENOSPC);
#endif
#ifdef ESPIPE
	T(ESPIPE);
#endif
#ifdef EROFS
	T(EROFS);
#endif
#ifdef EMLINK
	T(EMLINK);
#endif
#ifdef EPIPE
	T(EPIPE);
#endif
#ifdef EDOM
	T(EDOM);
#endif
#ifdef ERANGE
	T(ERANGE);
#endif
#ifdef EDEADLK
	T(EDEADLK);
#endif
#ifdef ENAMETOOLONG
	T(ENAMETOOLONG);
#endif
#ifdef ENOLCK
	T(ENOLCK);
#endif
#ifdef ENOSYS
	T(ENOSYS);
#endif
#ifdef ENOTEMPTY
	T(ENOTEMPTY);
#endif
#ifdef ELOOP
	T(ELOOP);
#endif
#ifdef EWOULDBLOCK
	T(EWOULDBLOCK);
#endif
#ifdef ENOMSG
	T(ENOMSG);
#endif
#ifdef EIDRM
	T(EIDRM);
#endif
#ifdef ECHRNG
	T(ECHRNG);
#endif
#ifdef EL2NSYNC
	T(EL2NSYNC);
#endif
#ifdef EL3HLT
	T(EL3HLT);
#endif
#ifdef EL3RST
	T(EL3RST);
#endif
#ifdef ELNRNG
	T(ELNRNG);
#endif
#ifdef EUNATCH
	T(EUNATCH);
#endif
#ifdef ENOCSI
	T(ENOCSI);
#endif
#ifdef EL2HLT
	T(EL2HLT);
#endif
#ifdef EBADE
	T(EBADE);
#endif
#ifdef EBADR
	T(EBADR);
#endif
#ifdef EXFULL
	T(EXFULL);
#endif
#ifdef ENOANO
	T(ENOANO);
#endif
#ifdef EBADRQC
	T(EBADRQC);
#endif
#ifdef EBADSLT
	T(EBADSLT);
#endif
#ifdef EDEADLOCK
	T(EDEADLOCK);
#endif
#ifdef EBFONT
	T(EBFONT);
#endif
#ifdef ENOSTR
	T(ENOSTR);
#endif
#ifdef ENODATA
	T(ENODATA);
#endif
#ifdef ETIME
	T(ETIME);
#endif
#ifdef ENOSR
	T(ENOSR);
#endif
#ifdef ENONET
	T(ENONET);
#endif
#ifdef ENOPKG
	T(ENOPKG);
#endif
#ifdef EREMOTE
	T(EREMOTE);
#endif
#ifdef ENOLINK
	T(ENOLINK);
#endif
#ifdef EADV
	T(EADV);
#endif
#ifdef ESRMNT
	T(ESRMNT);
#endif
#ifdef ECOMM
	T(ECOMM);
#endif
#ifdef EPROTO
	T(EPROTO);
#endif
#ifdef EMULTIHOP
	T(EMULTIHOP);
#endif
#ifdef EDOTDOT
	T(EDOTDOT);
#endif
#ifdef EBADMSG
	T(EBADMSG);
#endif
#ifdef EOVERFLOW
	T(EOVERFLOW);
#endif
#ifdef ENOTUNIQ
	T(ENOTUNIQ);
#endif
#ifdef EBADFD
	T(EBADFD);
#endif
#ifdef EREMCHG
	T(EREMCHG);
#endif
#ifdef ELIBACC
	T(ELIBACC);
#endif
#ifdef ELIBBAD
	T(ELIBBAD);
#endif
#ifdef ELIBSCN
	T(ELIBSCN);
#endif
#ifdef ELIBMAX
	T(ELIBMAX);
#endif
#ifdef ELIBEXEC
	T(ELIBEXEC);
#endif
#ifdef EILSEQ
	T(EILSEQ);
#endif
#ifdef ERESTART
	T(ERESTART);
#endif
#ifdef ESTRPIPE
	T(ESTRPIPE);
#endif
#ifdef EUSERS
	T(EUSERS);
#endif
#ifdef ENOTSOCK
	T(ENOTSOCK);
#endif
#ifdef ETOOMANYREF
	T(ETOOMANYREF);
#endif
#ifdef TADDRREQ
	T(TADDRREQ);
#endif
#ifdef EMSGSIZE
	T(EMSGSIZE);
#endif
#ifdef EPROTOTYPE
	T(EPROTOTYPE);
#endif
#ifdef ENOPROTOOPT
	T(ENOPROTOOPT);
#endif
#ifdef EPROTONOSUPPORT
	T(EPROTONOSUPPORT);
#endif
#ifdef ESOCKTNOSUPPORT
	T(ESOCKTNOSUPPORT);
#endif
#ifdef EOPNOTSUPP
	T(EOPNOTSUPP);
#endif
#ifdef EPFNOSUPPORT
	T(EPFNOSUPPORT);
#endif
#ifdef EAFNOSUPPORT
	T(EAFNOSUPPORT);
#endif
#ifdef EADDRINUSE
	T(EADDRINUSE);
#endif
#ifdef EADDRNOTAVAIL
	T(EADDRNOTAVAIL);
#endif
#ifdef ENETDOWN
	T(ENETDOWN);
#endif
#ifdef ENETUNREACH
	T(ENETUNREACH);
#endif
#ifdef ENETRESET
	T(ENETRESET);
#endif
#ifdef ECONNABORTED
	T(ECONNABORTED);
#endif
#ifdef ECONNRESET
	T(ECONNRESET);
#endif
#ifdef ENOBUFS
	T(ENOBUFS);
#endif
#ifdef EISCONN
	T(EISCONN);
#endif
#ifdef ENOTCONN
	T(ENOTCONN);
#endif
#ifdef ESHUTDOWN
	T(ESHUTDOWN);
#endif
#ifdef ETOOMANYREFS
	T(ETOOMANYREFS);
#endif
#ifdef ECONNREFUSED
	T(ECONNREFUSED);
#endif
#ifdef EHOSTDOWN
	T(EHOSTDOWN);
#endif
#ifdef EHOSTUNREACH
	T(EHOSTUNREACH);
#endif
#ifdef EALREADY
	T(EALREADY);
#endif
#ifdef EINPROGRESS
	T(EINPROGRESS);
#endif
#ifdef ESTALE
	T(ESTALE);
#endif
#ifdef EUCLEAN
	T(EUCLEAN);
#endif
#ifdef ENOTNAM
	T(ENOTNAM);
#endif
#ifdef ENAVAIL
	T(ENAVAIL);
#endif
#ifdef EISNAM
	T(EISNAM);
#endif
#ifdef EREMOTEIO
	T(EREMOTEIO);
#endif
#ifdef EDQUOT
	T(EDQUOT);
#endif
#ifdef ENOMEDIUM
	T(ENOMEDIUM);
#endif
#ifdef EMEDIUMTYPE
	T(EMEDIUMTYPE);
#endif
#ifdef ECANCELED
	T(ECANCELED);
#endif
#ifdef ENOKEY
	T(ENOKEY);
#endif
#ifdef EKEYEXPIRED
	T(EKEYEXPIRED);
#endif
#ifdef EKEYREVOKED
	T(EKEYREVOKED);
#endif
#ifdef EKEYREJECTED
	T(EKEYREJECTED);
#endif
	return 0;
}

/* attempt to guess the largest error value. assume gaps of 100 means that's the end of the list of errors */
static int
guess_max(void)
{
	int i;
	int miss_count;

	for(i = 0, miss_count = 0; i < INT_MAX; i++) {
		if(err_id(i)) {
			miss_count = 0;
		} else {
			miss_count++;

			if(miss_count > 100) break;
		}
	}

	return i - miss_count;
}

static void
init_id_lookup_table(void)
{
	unsigned i;
	id_max = guess_max();
	id_lookup_table = calloc(sizeof * id_lookup_table, id_max + 1);

	for(i = 0; i <= id_max; i++) {
		id_lookup_table[i] = err_id(i);
	}
}

static int
lookup_id_str(const char *str)
{
	unsigned i;
	assert(id_lookup_table != NULL);
	assert(id_max > 0);

	for(i = 0; i <= id_max; i++) {
		if(id_lookup_table[i] && !strcmp(str, id_lookup_table[i])) {
			return i;
		}
	}

	return -1;
}

static void
show_error(int e)
{
	const char *id;
	id = err_id(e);

	if(!id) id = "???";

	printf("%d:%s:%s\n", e, id, strerror(e));
}

static void
list_errors(void)
{
    unsigned e;
    // fprintf(stderr, "  max error: %d\n", max);
    assert(id_max > 0);
    for(e = 0; e <= id_max; e++) {
            const char *id = err_id(e);
            if (!id) continue;
            printf("%d:%s:%s\n", e, id, strerror(e));
    }
}

int
main(int argc, char **argv)
{
	if (argc == 1) {
usage:
		fprintf(stderr, "usage: %s [-l] <number | error_name>\n", argv[0]);
		fprintf(stderr, "  -l       : list errors\n");
		exit(1);
	} else {
		int i;
		init_id_lookup_table();

		for(i = 1; i < argc; i++) {
			const char *arg = argv[i];
			if (arg[0] == '-') {
				int j;
				for (j = 1; arg[j]; j++) {
					switch (arg[j]) {
					case 'l':
                                                list_errors();
                                                exit(0);
						break;
					default:
						goto usage;
					}
				}
				continue;
			}
			int e;
			char *endptr;
			e = strtol(arg, &endptr, 10);

			if(!endptr || *endptr) {
				e = lookup_id_str(arg);

				if(e < 0) {
					fprintf(stderr, "error '%s' unknown.\n", arg);
					continue;
				}
			}

			if(e < 0) e = -e;

			show_error(e);
		}
	}

	return 0;
}