/*
 * Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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 "dso_locl.h"
#include "internal/refcount.h"

static DSO_METHOD *default_DSO_meth = NULL;

static DSO *DSO_new_method(DSO_METHOD *meth)
{
    DSO *ret;

    if (default_DSO_meth == NULL) {
        /*
         * We default to DSO_METH_openssl() which in turn defaults to
         * stealing the "best available" method. Will fallback to
         * DSO_METH_null() in the worst case.
         */
        default_DSO_meth = DSO_METHOD_openssl();
    }
    ret = OPENSSL_zalloc(sizeof(*ret));
    if (ret == NULL) {
        DSOerr(DSO_F_DSO_NEW_METHOD, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    ret->meth_data = sk_void_new_null();
    if (ret->meth_data == NULL) {
        /* sk_new doesn't generate any errors so we do */
        DSOerr(DSO_F_DSO_NEW_METHOD, ERR_R_MALLOC_FAILURE);
        OPENSSL_free(ret);
        return NULL;
    }
    ret->meth = default_DSO_meth;
    ret->references = 1;
    ret->lock = CRYPTO_THREAD_lock_new();
    if (ret->lock == NULL) {
        DSOerr(DSO_F_DSO_NEW_METHOD, ERR_R_MALLOC_FAILURE);
        sk_void_free(ret->meth_data);
        OPENSSL_free(ret);
        return NULL;
    }

    if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {
        DSO_free(ret);
        ret = NULL;
    }

    return ret;
}

DSO *DSO_new(void)
{
    return DSO_new_method(NULL);
}

int DSO_free(DSO *dso)
{
    int i;

    if (dso == NULL)
        return 1;

    if (CRYPTO_DOWN_REF(&dso->references, &i, dso->lock) <= 0)
        return 0;

    REF_PRINT_COUNT("DSO", dso);
    if (i > 0)
        return 1;
    REF_ASSERT_ISNT(i < 0);

    if ((dso->flags & DSO_FLAG_NO_UNLOAD_ON_FREE) == 0) {
        if ((dso->meth->dso_unload != NULL) && !dso->meth->dso_unload(dso)) {
            DSOerr(DSO_F_DSO_FREE, DSO_R_UNLOAD_FAILED);
            return 0;
        }
    }

    if ((dso->meth->finish != NULL) && !dso->meth->finish(dso)) {
        DSOerr(DSO_F_DSO_FREE, DSO_R_FINISH_FAILED);
        return 0;
    }

    sk_void_free(dso->meth_data);
    OPENSSL_free(dso->filename);
    OPENSSL_free(dso->loaded_filename);
    CRYPTO_THREAD_lock_free(dso->lock);
    OPENSSL_free(dso);
    return 1;
}

int DSO_flags(DSO *dso)
{
    return ((dso == NULL) ? 0 : dso->flags);
}

int DSO_up_ref(DSO *dso)
{
    int i;

    if (dso == NULL) {
        DSOerr(DSO_F_DSO_UP_REF, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }

    if (CRYPTO_UP_REF(&dso->references, &i, dso->lock) <= 0)
        return 0;

    REF_PRINT_COUNT("DSO", r);
    REF_ASSERT_ISNT(i < 2);
    return ((i > 1) ? 1 : 0);
}

DSO *DSO_load(DSO *dso, const char *filename, DSO_METHOD *meth, int flags)
{
    DSO *ret;
    int allocated = 0;

    if (dso == NULL) {
        ret = DSO_new_method(meth);
        if (ret == NULL) {
            DSOerr(DSO_F_DSO_LOAD, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        allocated = 1;
        /* Pass the provided flags to the new DSO object */
        if (DSO_ctrl(ret, DSO_CTRL_SET_FLAGS, flags, NULL) < 0) {
            DSOerr(DSO_F_DSO_LOAD, DSO_R_CTRL_FAILED);
            goto err;
        }
    } else
        ret = dso;
    /* Don't load if we're currently already loaded */
    if (ret->filename != NULL) {
        DSOerr(DSO_F_DSO_LOAD, DSO_R_DSO_ALREADY_LOADED);
        goto err;
    }
    /*
     * filename can only be NULL if we were passed a dso that already has one
     * set.
     */
    if (filename != NULL)
        if (!DSO_set_filename(ret, filename)) {
            DSOerr(DSO_F_DSO_LOAD, DSO_R_SET_FILENAME_FAILED);
            goto err;
        }
    filename = ret->filename;
    if (filename == NULL) {
        DSOerr(DSO_F_DSO_LOAD, DSO_R_NO_FILENAME);
        goto err;
    }
    if (ret->meth->dso_load == NULL) {
        DSOerr(DSO_F_DSO_LOAD, DSO_R_UNSUPPORTED);
        goto err;
    }
    if (!ret->meth->dso_load(ret)) {
        DSOerr(DSO_F_DSO_LOAD, DSO_R_LOAD_FAILED);
        goto err;
    }
    /* Load succeeded */
    return ret;
 err:
    if (allocated)
        DSO_free(ret);
    return NULL;
}

DSO_FUNC_TYPE DSO_bind_func(DSO *dso, const char *symname)
{
    DSO_FUNC_TYPE ret = NULL;

    if ((dso == NULL) || (symname == NULL)) {
        DSOerr(DSO_F_DSO_BIND_FUNC, ERR_R_PASSED_NULL_PARAMETER);
        return NULL;
    }
    if (dso->meth->dso_bind_func == NULL) {
        DSOerr(DSO_F_DSO_BIND_FUNC, DSO_R_UNSUPPORTED);
        return NULL;
    }
    if ((ret = dso->meth->dso_bind_func(dso, symname)) == NULL) {
        DSOerr(DSO_F_DSO_BIND_FUNC, DSO_R_SYM_FAILURE);
        return NULL;
    }
    /* Success */
    return ret;
}

/*
 * I don't really like these *_ctrl functions very much to be perfectly
 * honest. For one thing, I think I have to return a negative value for any
 * error because possible DSO_ctrl() commands may return values such as
 * "size"s that can legitimately be zero (making the standard
 * "if (DSO_cmd(...))" form that works almost everywhere else fail at odd
 * times. I'd prefer "output" values to be passed by reference and the return
 * value as success/failure like usual ... but we conform when we must... :-)
 */
long DSO_ctrl(DSO *dso, int cmd, long larg, void *parg)
{
    if (dso == NULL) {
        DSOerr(DSO_F_DSO_CTRL, ERR_R_PASSED_NULL_PARAMETER);
        return -1;
    }
    /*
     * We should intercept certain generic commands and only pass control to
     * the method-specific ctrl() function if it's something we don't handle.
     */
    switch (cmd) {
    case DSO_CTRL_GET_FLAGS:
        return dso->flags;
    case DSO_CTRL_SET_FLAGS:
        dso->flags = (int)larg;
        return 0;
    case DSO_CTRL_OR_FLAGS:
        dso->flags |= (int)larg;
        return 0;
    default:
        break;
    }
    if ((dso->meth == NULL) || (dso->meth->dso_ctrl == NULL)) {
        DSOerr(DSO_F_DSO_CTRL, DSO_R_UNSUPPORTED);
        return -1;
    }
    return dso->meth->dso_ctrl(dso, cmd, larg, parg);
}

const char *DSO_get_filename(DSO *dso)
{
    if (dso == NULL) {
        DSOerr(DSO_F_DSO_GET_FILENAME, ERR_R_PASSED_NULL_PARAMETER);
        return NULL;
    }
    return dso->filename;
}

int DSO_set_filename(DSO *dso, const char *filename)
{
    char *copied;

    if ((dso == NULL) || (filename == NULL)) {
        DSOerr(DSO_F_DSO_SET_FILENAME, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }
    if (dso->loaded_filename) {
        DSOerr(DSO_F_DSO_SET_FILENAME, DSO_R_DSO_ALREADY_LOADED);
        return 0;
    }
    /* We'll duplicate filename */
    copied = OPENSSL_strdup(filename);
    if (copied == NULL) {
        DSOerr(DSO_F_DSO_SET_FILENAME, ERR_R_MALLOC_FAILURE);
        return 0;
    }
    OPENSSL_free(dso->filename);
    dso->filename = copied;
    return 1;
}

char *DSO_merge(DSO *dso, const char *filespec1, const char *filespec2)
{
    char *result = NULL;

    if (dso == NULL || filespec1 == NULL) {
        DSOerr(DSO_F_DSO_MERGE, ERR_R_PASSED_NULL_PARAMETER);
        return NULL;
    }
    if ((dso->flags & DSO_FLAG_NO_NAME_TRANSLATION) == 0) {
        if (dso->merger != NULL)
            result = dso->merger(dso, filespec1, filespec2);
        else if (dso->meth->dso_merger != NULL)
            result = dso->meth->dso_merger(dso, filespec1, filespec2);
    }
    return result;
}

char *DSO_convert_filename(DSO *dso, const char *filename)
{
    char *result = NULL;

    if (dso == NULL) {
        DSOerr(DSO_F_DSO_CONVERT_FILENAME, ERR_R_PASSED_NULL_PARAMETER);
        return NULL;
    }
    if (filename == NULL)
        filename = dso->filename;
    if (filename == NULL) {
        DSOerr(DSO_F_DSO_CONVERT_FILENAME, DSO_R_NO_FILENAME);
        return NULL;
    }
    if ((dso->flags & DSO_FLAG_NO_NAME_TRANSLATION) == 0) {
        if (dso->name_converter != NULL)
            result = dso->name_converter(dso, filename);
        else if (dso->meth->dso_name_converter != NULL)
            result = dso->meth->dso_name_converter(dso, filename);
    }
    if (result == NULL) {
        result = OPENSSL_strdup(filename);
        if (result == NULL) {
            DSOerr(DSO_F_DSO_CONVERT_FILENAME, ERR_R_MALLOC_FAILURE);
            return NULL;
        }
    }
    return result;
}

int DSO_pathbyaddr(void *addr, char *path, int sz)
{
    DSO_METHOD *meth = default_DSO_meth;
    if (meth == NULL)
        meth = DSO_METHOD_openssl();
    if (meth->pathbyaddr == NULL) {
        DSOerr(DSO_F_DSO_PATHBYADDR, DSO_R_UNSUPPORTED);
        return -1;
    }
    return (*meth->pathbyaddr) (addr, path, sz);
}

DSO *DSO_dsobyaddr(void *addr, int flags)
{
    DSO *ret = NULL;
    char *filename = NULL;
    int len = DSO_pathbyaddr(addr, NULL, 0);

    if (len < 0)
        return NULL;

    filename = OPENSSL_malloc(len);
    if (filename != NULL
            && DSO_pathbyaddr(addr, filename, len) == len)
        ret = DSO_load(NULL, filename, NULL, flags);

    OPENSSL_free(filename);
    return ret;
}

void *DSO_global_lookup(const char *name)
{
    DSO_METHOD *meth = default_DSO_meth;
    if (meth == NULL)
        meth = DSO_METHOD_openssl();
    if (meth->globallookup == NULL) {
        DSOerr(DSO_F_DSO_GLOBAL_LOOKUP, DSO_R_UNSUPPORTED);
        return NULL;
    }
    return (*meth->globallookup) (name);
}