/* ====================================================================
 * Copyright (c) 2015 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 */

/* #define COMPILE_STANDALONE_TEST_DRIVER  */
#include "apps.h"
#include <string.h>
#if !defined(OPENSSL_SYS_MSDOS)
# include OPENSSL_UNISTD
#endif

#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <openssl/bio.h>

#define MAX_OPT_HELP_WIDTH 30
const char OPT_HELP_STR[] = "--";
const char OPT_MORE_STR[] = "---";

/* Our state */
static char **argv;
static int argc;
static int opt_index;
static char *arg;
static char *flag;
static char *dunno;
static const OPTIONS *unknown;
static const OPTIONS *opts;
static char prog[40];

/*
 * Return the simple name of the program; removing various platform gunk.
 */
#if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_NETWARE)
char *opt_progname(const char *argv0)
{
    size_t i, n;
    const char *p;
    char *q;

    /* find the last '/', '\' or ':' */
    for (p = argv0 + strlen(argv0); --p > argv0;)
        if (*p == '/' || *p == '\\' || *p == ':') {
            p++;
            break;
        }

    /* Strip off trailing nonsense. */
    n = strlen(p);
    if (n > 4 &&
        (strcmp(&p[n - 4], ".exe") == 0 || strcmp(&p[n - 4], ".EXE") == 0))
        n -= 4;
#if defined(OPENSSL_SYS_NETWARE)
    if (n > 4 &&
        (strcmp(&p[n - 4], ".nlm") == 0 || strcmp(&p[n - 4], ".NLM") == 0))
        n -= 4;
#endif

    /* Copy over the name, in lowercase. */
    if (n > sizeof prog - 1)
        n = sizeof prog - 1;
    for (q = prog, i = 0; i < n; i++, p++)
        *q++ = isupper(*p) ? tolower(*p) : *p;
    *q = '\0';
    return prog;
}

#elif defined(OPENSSL_SYS_VMS)

char *opt_progname(const char *argv0)
{
    const char *p, *q;

    /* Find last special charcter sys:[foo.bar]openssl */
    for (p = argv0 + strlen(argv0); --p > argv0;)
        if (*p == ':' || *p == ']' || *p == '>') {
            p++;
            break;
        }

    q = strrchr(p, '.');
    strncpy(prog, p, sizeof prog - 1);
    prog[sizeof prog - 1] = '\0';
    if (q == NULL || q - p >= sizeof prog)
        prog[q - p] = '\0';
    return prog;
}

#else

char *opt_progname(const char *argv0)
{
    const char *p;

    /* Could use strchr, but this is like the ones above. */
    for (p = argv0 + strlen(argv0); --p > argv0;)
        if (*p == '/') {
            p++;
            break;
        }
    strncpy(prog, p, sizeof prog - 1);
    prog[sizeof prog - 1] = '\0';
    return prog;
}
#endif

char *opt_getprog(void)
{
    return prog;
}

/* Set up the arg parsing. */
char *opt_init(int ac, char **av, const OPTIONS *o)
{
    /* Store state. */
    argc = ac;
    argv = av;
    opt_index = 1;
    opts = o;
    opt_progname(av[0]);
    unknown = NULL;

    for (; o->name; ++o) {
        const OPTIONS *next;
#ifndef NDEBUG
        int duplicated, i;
#endif

        if (o->name == OPT_HELP_STR || o->name == OPT_MORE_STR)
            continue;
#ifndef NDEBUG
        i = o->valtype;

        /* Make sure options are legit. */
        assert(o->name[0] != '-');
        assert(o->retval > 0);
        assert(i == 0 || i == '-'
               || i == 'n' || i == 'p' || i == 'u'
               || i == 's' || i == '<' || i == '>' || i == '/'
               || i == 'f' || i == 'F');

        /* Make sure there are no duplicates. */
        for (next = o + 1; next->name; ++next) {
            /*
             * Some compilers inline strcmp and the assert string is too long.
             */
            duplicated = strcmp(o->name, next->name) == 0;
            assert(!duplicated);
        }
#endif
        if (o->name[0] == '\0') {
            assert(unknown == NULL);
            unknown = o;
            assert(unknown->valtype == 0 || unknown->valtype == '-');
        }
    }
    return prog;
}

static OPT_PAIR formats[] = {
    {"PEM/DER", OPT_FMT_PEMDER},
    {"pkcs12", OPT_FMT_PKCS12},
    {"smime", OPT_FMT_SMIME},
    {"engine", OPT_FMT_ENGINE},
    {"msblob", OPT_FMT_MSBLOB},
    {"netscape", OPT_FMT_NETSCAPE},
    {"nss", OPT_FMT_NSS},
    {"text", OPT_FMT_TEXT},
    {"http", OPT_FMT_HTTP},
    {"pvk", OPT_FMT_PVK},
    {NULL}
};

/* Print an error message about a failed format parse. */
int opt_format_error(const char *s, unsigned long flags)
{
    OPT_PAIR *ap;

    if (flags == OPT_FMT_PEMDER)
        BIO_printf(bio_err, "%s: Bad format \"%s\"; must be pem or der\n",
                   prog, s);
    else {
        BIO_printf(bio_err, "%s: Bad format \"%s\"; must be one of:\n",
                   prog, s);
        for (ap = formats; ap->name; ap++)
            if (flags & ap->retval)
                BIO_printf(bio_err, "   %s\n", ap->name);
    }
    return 0;
}

/* Parse a format string, put it into *result; return 0 on failure, else 1. */
int opt_format(const char *s, unsigned long flags, int *result)
{
    switch (*s) {
    default:
        return 0;
    case 'D':
    case 'd':
        if ((flags & OPT_FMT_PEMDER) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_ASN1;
        break;
    case 'T':
    case 't':
        if ((flags & OPT_FMT_TEXT) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_TEXT;
        break;
    case 'N':
    case 'n':
        if ((flags & OPT_FMT_NSS) == 0)
            return opt_format_error(s, flags);
        if (strcmp(s, "NSS") != 0 && strcmp(s, "nss") != 0)
            return opt_format_error(s, flags);
        *result = FORMAT_NSS;
        break;
    case 'S':
    case 's':
        if ((flags & OPT_FMT_SMIME) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_SMIME;
        break;
    case 'M':
    case 'm':
        if ((flags & OPT_FMT_MSBLOB) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_MSBLOB;
        break;
    case 'E':
    case 'e':
        if ((flags & OPT_FMT_ENGINE) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_ENGINE;
        break;
    case 'H':
    case 'h':
        if ((flags & OPT_FMT_HTTP) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_HTTP;
        break;
    case '1':
        if ((flags & OPT_FMT_PKCS12) == 0)
            return opt_format_error(s, flags);
        *result = FORMAT_PKCS12;
        break;
    case 'P':
    case 'p':
        if (s[1] == '\0' || strcmp(s, "PEM") == 0 || strcmp(s, "pem") == 0) {
            if ((flags & OPT_FMT_PEMDER) == 0)
                return opt_format_error(s, flags);
            *result = FORMAT_PEM;
        } else if (strcmp(s, "PVK") == 0 || strcmp(s, "pvk") == 0) {
            if ((flags & OPT_FMT_PVK) == 0)
                return opt_format_error(s, flags);
            *result = FORMAT_PVK;
        } else if (strcmp(s, "P12") == 0 || strcmp(s, "p12") == 0
                   || strcmp(s, "PKCS12") == 0 || strcmp(s, "pkcs12") == 0) {
            if ((flags & OPT_FMT_PKCS12) == 0)
                return opt_format_error(s, flags);
            *result = FORMAT_PKCS12;
        } else
            return 0;
        break;
    }
    return 1;
}

/* Parse a cipher name, put it in *EVP_CIPHER; return 0 on failure, else 1. */
int opt_cipher(const char *name, const EVP_CIPHER **cipherp)
{
    *cipherp = EVP_get_cipherbyname(name);
    if (*cipherp)
        return 1;
    BIO_printf(bio_err, "%s: Unknown cipher %s\n", prog, name);
    return 0;
}

/*
 * Parse message digest name, put it in *EVP_MD; return 0 on failure, else 1.
 */
int opt_md(const char *name, const EVP_MD **mdp)
{
    *mdp = EVP_get_digestbyname(name);
    if (*mdp)
        return 1;
    BIO_printf(bio_err, "%s: Unknown digest %s\n", prog, name);
    return 0;
}

/* Look through a list of name/value pairs. */
int opt_pair(const char *name, const OPT_PAIR* pairs, int *result)
{
    const OPT_PAIR *pp;

    for (pp = pairs; pp->name; pp++)
        if (strcmp(pp->name, name) == 0) {
            *result = pp->retval;
            return 1;
        }
    BIO_printf(bio_err, "%s: Value must be one of:\n", prog);
    for (pp = pairs; pp->name; pp++)
        BIO_printf(bio_err, "\t%s\n", pp->name);
    return 0;
}

/* See if cp looks like a hex number, in case user left off the 0x */
static int scanforhex(const char *cp)
{
    if (*cp == '0' && (cp[1] == 'x' || cp[1] == 'X'))
        return 16;
    for (; *cp; cp++)
        /* Look for a hex digit that isn't a regular digit. */
        if (isxdigit(*cp) && !isdigit(*cp))
            return 16;
    return 0;
}

/* Parse an int, put it into *result; return 0 on failure, else 1. */
int opt_int(const char *value, int *result)
{
    const char *fmt = "%d";
    int base = scanforhex(value);

    if (base == 16)
        fmt = "%x";
    else if (*value == '0')
        fmt = "%o";
    if (sscanf(value, fmt, result) != 1) {
        BIO_printf(bio_err, "%s: Can't parse \"%s\" as a number\n",
                   prog, value);
        return 0;
    }
    return 1;
}

/* Parse a long, put it into *result; return 0 on failure, else 1. */
int opt_long(const char *value, long *result)
{
    char *endptr;
    int base = scanforhex(value);

    *result = strtol(value, &endptr, base);
    if (*endptr) {
        BIO_printf(bio_err,
                   "%s: Bad char %c in number %s\n", prog, *endptr, value);
        return 0;
    }
    return 1;
}

/*
 * Parse an unsigned long, put it into *result; return 0 on failure, else 1.
 */
int opt_ulong(const char *value, unsigned long *result)
{
    char *endptr;
    int base = scanforhex(value);

    *result = strtoul(value, &endptr, base);
    if (*endptr) {
        BIO_printf(bio_err,
                   "%s: Bad char %c in number %s\n", prog, *endptr, value);
        return 0;
    }
    return 1;
}

/*
 * We pass opt as an int but cast it to "enum range" so that all the
 * items in the OPT_V_ENUM enumeration are caught; this makes -Wswitch
 * in gcc do the right thing.
 */
enum range { OPT_V_ENUM };

int opt_verify(int opt, X509_VERIFY_PARAM *vpm)
{
    unsigned long ul;
    int i;
    ASN1_OBJECT *otmp;
    X509_PURPOSE *xptmp;
    const X509_VERIFY_PARAM *vtmp;

    assert(vpm != NULL);
    assert(opt > OPT_V__FIRST);
    assert(opt < OPT_V__LAST);

    switch ((enum range)opt) {
    case OPT_V__FIRST:
    case OPT_V__LAST:
        return 0;
    case OPT_V_POLICY:
        otmp = OBJ_txt2obj(opt_arg(), 0);
        if (otmp == NULL) {
            BIO_printf(bio_err, "%s: Invalid Policy %s\n", prog, opt_arg());
            return 0;
        }
        X509_VERIFY_PARAM_add0_policy(vpm, otmp);
        break;
    case OPT_V_PURPOSE:
        i = X509_PURPOSE_get_by_sname(opt_arg());
        if (i < 0) {
            BIO_printf(bio_err, "%s: Invalid purpose %s\n", prog, opt_arg());
            return 0;
        }
        xptmp = X509_PURPOSE_get0(i);
        i = X509_PURPOSE_get_id(xptmp);
        X509_VERIFY_PARAM_set_purpose(vpm, i);
        break;
    case OPT_V_VERIFY_NAME:
        vtmp = X509_VERIFY_PARAM_lookup(opt_arg());
        if (vtmp == NULL) {
            BIO_printf(bio_err, "%s: Invalid verify name %s\n",
                       prog, opt_arg());
            return 0;
        }
        X509_VERIFY_PARAM_set1(vpm, vtmp);
        break;
    case OPT_V_VERIFY_DEPTH:
        i = atoi(opt_arg());
        if (i >= 0)
            X509_VERIFY_PARAM_set_depth(vpm, i);
        break;
    case OPT_V_ATTIME:
        opt_ulong(opt_arg(), &ul);
        if (ul)
            X509_VERIFY_PARAM_set_time(vpm, (time_t)ul);
        break;
    case OPT_V_VERIFY_HOSTNAME:
        if (!X509_VERIFY_PARAM_set1_host(vpm, opt_arg(), 0))
            return 0;
        break;
    case OPT_V_VERIFY_EMAIL:
        if (!X509_VERIFY_PARAM_set1_email(vpm, opt_arg(), 0))
            return 0;
        break;
    case OPT_V_VERIFY_IP:
        if (!X509_VERIFY_PARAM_set1_ip_asc(vpm, opt_arg()))
            return 0;
        break;
    case OPT_V_IGNORE_CRITICAL:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_IGNORE_CRITICAL);
        break;
    case OPT_V_ISSUER_CHECKS:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_CB_ISSUER_CHECK);
        break;
    case OPT_V_CRL_CHECK:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_CRL_CHECK);
        break;
    case OPT_V_CRL_CHECK_ALL:
        X509_VERIFY_PARAM_set_flags(vpm,
                                    X509_V_FLAG_CRL_CHECK |
                                    X509_V_FLAG_CRL_CHECK_ALL);
        break;
    case OPT_V_POLICY_CHECK:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_POLICY_CHECK);
        break;
    case OPT_V_EXPLICIT_POLICY:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_EXPLICIT_POLICY);
        break;
    case OPT_V_INHIBIT_ANY:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_INHIBIT_ANY);
        break;
    case OPT_V_INHIBIT_MAP:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_INHIBIT_MAP);
        break;
    case OPT_V_X509_STRICT:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_X509_STRICT);
        break;
    case OPT_V_EXTENDED_CRL:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_EXTENDED_CRL_SUPPORT);
        break;
    case OPT_V_USE_DELTAS:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_USE_DELTAS);
        break;
    case OPT_V_POLICY_PRINT:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_NOTIFY_POLICY);
        break;
    case OPT_V_CHECK_SS_SIG:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_CHECK_SS_SIGNATURE);
        break;
    case OPT_V_TRUSTED_FIRST:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_TRUSTED_FIRST);
        break;
    case OPT_V_SUITEB_128_ONLY:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_SUITEB_128_LOS_ONLY);
        break;
    case OPT_V_SUITEB_128:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_SUITEB_128_LOS);
        break;
    case OPT_V_SUITEB_192:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_SUITEB_192_LOS);
        break;
    case OPT_V_PARTIAL_CHAIN:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_PARTIAL_CHAIN);
        break;
    case OPT_V_NO_ALT_CHAINS:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_NO_ALT_CHAINS);
	break;
    case OPT_V_NO_CHECK_TIME:
        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_NO_CHECK_TIME);
	break;
    }
    return 1;

}

/*
 * Parse the next flag (and value if specified), return 0 if done, -1 on
 * error, otherwise the flag's retval.
 */
int opt_next(void)
{
    char *p;
    char *endptr;
    const OPTIONS *o;
    int dummy;
    int base;
    long val;

    /* Look at current arg; at end of the list? */
    arg = NULL;
    p = argv[opt_index];
    if (p == NULL)
        return 0;

    /* If word doesn't start with a -, we're done. */
    if (*p != '-')
        return 0;

    /* Hit "--" ? We're done. */
    opt_index++;
    if (strcmp(p, "--") == 0)
        return 0;

    /* Allow -nnn and --nnn */
    if (*++p == '-')
        p++;
    flag = p - 1;

    /* If we have --flag=foo, snip it off */
    if ((arg = strchr(p, '=')) != NULL)
        *arg++ = '\0';
    for (o = opts; o->name; ++o) {
        /* If not this option, move on to the next one. */
        if (strcmp(p, o->name) != 0)
            continue;

        /* If it doesn't take a value, make sure none was given. */
        if (o->valtype == 0 || o->valtype == '-') {
            if (arg) {
                BIO_printf(bio_err,
                           "%s: Option -%s does not take a value\n", prog, p);
                return -1;
            }
            return o->retval;
        }

        /* Want a value; get the next param if =foo not used. */
        if (arg == NULL) {
            if (argv[opt_index] == NULL) {
                BIO_printf(bio_err,
                           "%s: Option -%s needs a value\n", prog, o->name);
                return -1;
            }
            arg = argv[opt_index++];
        }

        /* Syntax-check value. */
        /*
         * Do some basic syntax-checking on the value.  These tests aren't
         * perfect (ignore range overflow) but they catch common failures.
         */
        switch (o->valtype) {
        default:
        case 's':
            /* Just a string. */
            break;
        case '/':
            if (app_isdir(arg) >= 0)
                break;
            BIO_printf(bio_err, "%s: Not a directory: %s\n", prog, arg);
            return -1;
        case '<':
            /* Input file. */
            if (strcmp(arg, "-") == 0 || app_access(arg, R_OK) >= 0)
                break;
            BIO_printf(bio_err,
                       "%s: Cannot open input file %s, %s\n",
                       prog, arg, strerror(errno));
            return -1;
        case '>':
            /* Output file. */
            if (strcmp(arg, "-") == 0 || app_access(arg, W_OK) >= 0 || errno == ENOENT)
                break;
            BIO_printf(bio_err,
                       "%s: Cannot open output file %s, %s\n",
                       prog, arg, strerror(errno));
            return -1;
        case 'p':
        case 'n':
            base = scanforhex(arg);
            val = strtol(arg, &endptr, base);
            if (*endptr == '\0') {
                if (o->valtype == 'p' && val <= 0) {
                    BIO_printf(bio_err,
                               "%s: Non-positive number \"%s\" for -%s\n",
                               prog, arg, o->name);
                    return -1;
                }
                break;
            }
            BIO_printf(bio_err,
                       "%s: Invalid number \"%s\" for -%s\n",
                       prog, arg, o->name);
            return -1;
        case 'u':
            base = scanforhex(arg);
            strtoul(arg, &endptr, base);
            if (*endptr == '\0')
                break;
            BIO_printf(bio_err,
                       "%s: Invalid number \"%s\" for -%s\n",
                       prog, arg, o->name);
            return -1;
        case 'f':
        case 'F':
            if (opt_format(arg,
                           o->valtype == 'F' ? OPT_FMT_PEMDER
                           : OPT_FMT_ANY, &dummy))
                break;
            BIO_printf(bio_err,
                       "%s: Invalid format \"%s\" for -%s\n",
                       prog, arg, o->name);
            return -1;
        }

        /* Return the flag value. */
        return o->retval;
    }
    if (unknown != NULL) {
        dunno = p;
        return unknown->retval;
    }
    BIO_printf(bio_err, "%s: Option unknown option -%s\n", prog, p);
    return -1;
}

/* Return the most recent flag parameter. */
char *opt_arg(void)
{
    return arg;
}

/* Return the most recent flag. */
char *opt_flag(void)
{
    return flag;
}

/* Return the unknown option. */
char *opt_unknown(void)
{
    return dunno;
}

/* Return the rest of the arguments after parsing flags. */
char **opt_rest(void)
{
    return &argv[opt_index];
}

/* How many items in remaining args? */
int opt_num_rest(void)
{
    int i = 0;
    char **pp;

    for (pp = opt_rest(); *pp; pp++, i++)
        continue;
    return i;
}

/* Return a string describing the parameter type. */
static const char *valtype2param(const OPTIONS *o)
{
    switch (o->valtype) {
    case '-':
        return "";
    case 's':
        return "val";
    case '/':
        return "dir";
    case '<':
        return "infile";
    case '>':
        return "outfile";
    case 'p':
        return "pnum";
    case 'n':
        return "num";
    case 'u':
        return "unum";
    case 'F':
        return "der/pem";
    case 'f':
        return "format";
    }
    return "parm";
}

void opt_help(const OPTIONS *list)
{
    const OPTIONS *o;
    int i;
    int standard_prolog;
    int width = 5;
    char start[80 + 1];
    char *p;
    const char *help;

    /* Starts with its own help message? */
    standard_prolog = list[0].name != OPT_HELP_STR;

    /* Find the widest help. */
    for (o = list; o->name; o++) {
        if (o->name == OPT_MORE_STR)
            continue;
        i = 2 + (int)strlen(o->name);
        if (o->valtype != '-')
            i += 1 + strlen(valtype2param(o));
        if (i < MAX_OPT_HELP_WIDTH && i > width)
            width = i;
        assert(i < (int)sizeof start);
    }

    if (standard_prolog)
        BIO_printf(bio_err, "Usage: %s [options]\nValid options are:\n",
                   prog);

    /* Now let's print. */
    for (o = list; o->name; o++) {
        help = o->helpstr ? o->helpstr : "(No additional info)";
        if (o->name == OPT_HELP_STR) {
            BIO_printf(bio_err, help, prog);
            continue;
        }

        /* Pad out prefix */
        memset(start, ' ', sizeof(start) - 1);
        start[sizeof start - 1] = '\0';

        if (o->name == OPT_MORE_STR) {
            /* Continuation of previous line; padd and print. */
            start[width] = '\0';
            BIO_printf(bio_err, "%s  %s\n", start, help);
            continue;
        }

        /* Build up the "-flag [param]" part. */
        p = start;
        *p++ = ' ';
        *p++ = '-';
        if (o->name[0])
            p += strlen(strcpy(p, o->name));
        else
            *p++ = '*';
        if (o->valtype != '-') {
            *p++ = ' ';
            p += strlen(strcpy(p, valtype2param(o)));
        }
        *p = ' ';
        if ((int)(p - start) >= MAX_OPT_HELP_WIDTH) {
            *p = '\0';
            BIO_printf(bio_err, "%s\n", start);
            memset(start, ' ', sizeof(start));
        }
        start[width] = '\0';
        BIO_printf(bio_err, "%s  %s\n", start, help);
    }
}

#ifdef COMPILE_STANDALONE_TEST_DRIVER
# include <sys/stat.h>

typedef enum OPTION_choice {
    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
    OPT_IN, OPT_INFORM, OPT_OUT, OPT_COUNT, OPT_U, OPT_FLAG,
    OPT_STR, OPT_NOTUSED
} OPTION_CHOICE;

static OPTIONS options[] = {
    {OPT_HELP_STR, 1, '-', "Usage: %s flags\n"},
    {OPT_HELP_STR, 1, '-', "Valid options are:\n"},
    {"help", OPT_HELP, '-', "Display this summary"},
    {"in", OPT_IN, '<', "input file"},
    {OPT_MORE_STR, 1, '-', "more detail about input"},
    {"inform", OPT_INFORM, 'f', "input file format; defaults to pem"},
    {"out", OPT_OUT, '>', "output file"},
    {"count", OPT_COUNT, 'p', "a counter greater than zero"},
    {"u", OPT_U, 'u', "an unsigned number"},
    {"flag", OPT_FLAG, 0, "just some flag"},
    {"str", OPT_STR, 's', "the magic word"},
    {"areallyverylongoption", OPT_HELP, '-', "long way for help"},
    {NULL}
};

BIO *bio_err;

int app_isdir(const char *name)
{
    struct stat sb;

    return name != NULL && stat(name, &sb) >= 0 && S_ISDIR(sb.st_mode);
}

int main(int ac, char **av)
{
    OPTION_CHOICE o;
    char **rest;
    char *prog;

    bio_err = BIO_new_fp(stderr, BIO_NOCLOSE | BIO_FP_TEXT);

    prog = opt_init(ac, av, options);
    while ((o = opt_next()) != OPT_EOF) {
        switch (c) {
        case OPT_NOTUSED:
        case OPT_EOF:
        case OPT_ERR:
            printf("%s: Usage error; try -help.\n", prog);
            return 1;
        case OPT_HELP:
            opt_help(options);
            return 0;
        case OPT_IN:
            printf("in %s\n", opt_arg());
            break;
        case OPT_INFORM:
            printf("inform %s\n", opt_arg());
            break;
        case OPT_OUT:
            printf("out %s\n", opt_arg());
            break;
        case OPT_COUNT:
            printf("count %s\n", opt_arg());
            break;
        case OPT_U:
            printf("u %s\n", opt_arg());
            break;
        case OPT_FLAG:
            printf("flag\n");
            break;
        case OPT_STR:
            printf("str %s\n", opt_arg());
            break;
        }
    }
    argc = opt_num_rest();
    argv = opt_rest();

    printf("args = %d\n", argc);
    if (argc)
        while (*argv)
            printf("  %s\n", *argv++);
    return 0;
}
#endif