/*

 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#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 <limits.h>

#include <openssl/bio.h>

#include <openssl/x509v3.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)

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;

    /* 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++ = tolower((unsigned char)*p);

    *q = '\0';

    return prog;

}

#elif defined(OPENSSL_SYS_VMS)

char *opt_progname(const char *argv0)

{

    const char *p, *q;

    /* Find last special character 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) {

#ifndef NDEBUG

        const OPTIONS *next;

        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);

        switch (i) {

        case   0: case '-': case '/': case '<': case '>': case 'E': case 'F':

        case 'M': case 'U': case 'f': case 'l': case 'n': case 'p': case 's':

        case 'u': case 'c':

            break;

        default:

            assert(0);

        }

        /* 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},

    {"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 != NULL)

        return 1;

    BIO_printf(bio_err, "%s: Unrecognized flag %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 != NULL)

        return 1;

    BIO_printf(bio_err, "%s: Unrecognized flag %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;

}

/* Parse an int, put it into *result; return 0 on failure, else 1. */

int opt_int(const char *value, int *result)

{

    long l;

    if (!opt_long(value, &l))

        return 0;

    *result = (int)l;

    if (*result != l) {

        BIO_printf(bio_err, "%s: Value \"%s\" outside integer range\n",

                   prog, value);

        return 0;

    }

    return 1;

}

static void opt_number_error(const char *v)

{

    size_t i = 0;

    struct strstr_pair_st {

        char *prefix;

        char *name;

    } b[] = {

        {"0x", "a hexadecimal"},

        {"0X", "a hexadecimal"},

        {"0", "an octal"}

    };

    for (i = 0; i < OSSL_NELEM(b); i++) {

        if (strncmp(v, b[i].prefix, strlen(b[i].prefix)) == 0) {

            BIO_printf(bio_err,

                       "%s: Can't parse \"%s\" as %s number\n",

                       prog, v, b[i].name);

            return;

        }

    }

    BIO_printf(bio_err, "%s: Can't parse \"%s\" as a number\n", prog, v);

    return;

}

/* Parse a long, put it into *result; return 0 on failure, else 1. */

int opt_long(const char *value, long *result)

{

    int oerrno = errno;

    long l;

    char *endp;

    errno = 0;

    l = strtol(value, &endp, 0);

    if (*endp

            || endp == value

            || ((l == LONG_MAX || l == LONG_MIN) && errno == ERANGE)

            || (l == 0 && errno != 0)) {

        opt_number_error(value);

        errno = oerrno;

        return 0;

    }

    *result = l;

    errno = oerrno;

    return 1;

}

#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L && \

    defined(INTMAX_MAX) && defined(UINTMAX_MAX)

/* Parse an intmax_t, put it into *result; return 0 on failure, else 1. */

int opt_imax(const char *value, intmax_t *result)

{

    int oerrno = errno;

    intmax_t m;

    char *endp;

    errno = 0;

    m = strtoimax(value, &endp, 0);

    if (*endp

            || endp == value

            || ((m == INTMAX_MAX || m == INTMAX_MIN) && errno == ERANGE)

            || (m == 0 && errno != 0)) {

        opt_number_error(value);

        errno = oerrno;

        return 0;

    }

    *result = m;

    errno = oerrno;

    return 1;

}

/* Parse a uintmax_t, put it into *result; return 0 on failure, else 1. */

int opt_umax(const char *value, uintmax_t *result)

{

    int oerrno = errno;

    uintmax_t m;

    char *endp;

    errno = 0;

    m = strtoumax(value, &endp, 0);

    if (*endp

            || endp == value

            || (m == UINTMAX_MAX && errno == ERANGE)

            || (m == 0 && errno != 0)) {

        opt_number_error(value);

        errno = oerrno;

        return 0;

    }

    *result = m;

    errno = oerrno;

    return 1;

}

#endif

/*

 * Parse an unsigned long, put it into *result; return 0 on failure, else 1.

 */

int opt_ulong(const char *value, unsigned long *result)

{

    int oerrno = errno;

    char *endptr;

    unsigned long l;

    errno = 0;

    l = strtoul(value, &endptr, 0);

    if (*endptr

            || endptr == value

            || ((l == ULONG_MAX) && errno == ERANGE)

            || (l == 0 && errno != 0)) {

        opt_number_error(value);

        errno = oerrno;

        return 0;

    }

    *result = l;

    errno = oerrno;

    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)

{

    int i;

    ossl_intmax_t t = 0;

    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:

        /* purpose name -> purpose index */

        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;

        }

        /* purpose index -> purpose object */

        xptmp = X509_PURPOSE_get0(i);

        /* purpose object -> purpose value */

        i = X509_PURPOSE_get_id(xptmp);

        if (!X509_VERIFY_PARAM_set_purpose(vpm, i)) {

            BIO_printf(bio_err,

                       "%s: Internal error setting purpose %s\n",

                       prog, opt_arg());

            return 0;

        }

        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_VERIFY_AUTH_LEVEL:

        i = atoi(opt_arg());

        if (i >= 0)

            X509_VERIFY_PARAM_set_auth_level(vpm, i);

        break;

    case OPT_V_ATTIME:

        if (!opt_imax(opt_arg(), &t))

            return 0;

        if (t != (time_t)t) {

            BIO_printf(bio_err, "%s: epoch time out of range %s\n",

                       prog, opt_arg());

            return 0;

        }

        X509_VERIFY_PARAM_set_time(vpm, (time_t)t);

        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:

        /* NOP, deprecated */

        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;

    case OPT_V_ALLOW_PROXY_CERTS:

        X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_ALLOW_PROXY_CERTS);

        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;

    const OPTIONS *o;

    int ival;

    long lval;

    unsigned long ulval;

    ossl_intmax_t imval;

    ossl_uintmax_t umval;

    /* 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. */

        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. */

            break;

        case '>':

            /* Output file. */

            break;

        case 'p':

        case 'n':

            if (!opt_int(arg, &ival)

                    || (o->valtype == 'p' && ival <= 0)) {

                BIO_printf(bio_err,

                           "%s: Non-positive number \"%s\" for -%s\n",

                           prog, arg, o->name);

                return -1;

            }

            break;

        case 'M':

            if (!opt_imax(arg, &imval)) {

                BIO_printf(bio_err,

                           "%s: Invalid number \"%s\" for -%s\n",

                           prog, arg, o->name);

                return -1;

            }

            break;

        case 'U':

            if (!opt_umax(arg, &umval)) {

                BIO_printf(bio_err,

                           "%s: Invalid number \"%s\" for -%s\n",

                           prog, arg, o->name);

                return -1;

            }

            break;

        case 'l':

            if (!opt_long(arg, &lval)) {

                BIO_printf(bio_err,

                           "%s: Invalid number \"%s\" for -%s\n",

                           prog, arg, o->name);

                return -1;

            }

            break;

        case 'u':

            if (!opt_ulong(arg, &ulval)) {

                BIO_printf(bio_err,

                           "%s: Invalid number \"%s\" for -%s\n",

                           prog, arg, o->name);

                return -1;

            }

            break;

        case 'c':

        case 'E':

        case 'F':

        case 'f':

            if (opt_format(arg,

                           o->valtype == 'c' ? OPT_FMT_PDS :

                           o->valtype == 'E' ? OPT_FMT_PDE :

                           o->valtype == 'F' ? OPT_FMT_PEMDER

                           : OPT_FMT_ANY, &ival))

                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 0:

    case '-':

        return "";

    case 's':

        return "val";

    case '/':

        return "dir";

    case '<':

        return "infile";

    case '>':

        return "outfile";

    case 'p':

        return "+int";

    case 'n':

        return "int";

    case 'l':

        return "long";

    case 'u':

        return "ulong";

    case 'E':

        return "PEM|DER|ENGINE";

    case 'F':

        return "PEM|DER";

    case 'f':

        return "format";

    case 'M':

        return "intmax";

    case 'U':

        return "uintmax";

    }

    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; pad 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++ = '-';