/* dso_dlfcn.c -*- mode:C; c-file-style: "eay" -*- */
/*
 * Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL project
 * 2000.
 */
/* ====================================================================
 * Copyright (c) 2000 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/dso.h>

#ifndef DSO_DLFCN
DSO_METHOD *DSO_METHOD_dlfcn(void)
{
    return NULL;
}
#else

# ifdef HAVE_DLFCN_H
#  include <dlfcn.h>
# endif

/* Part of the hack in "dlfcn_load" ... */
# define DSO_MAX_TRANSLATED_SIZE 256

static int dlfcn_load(DSO *dso);
static int dlfcn_unload(DSO *dso);
static void *dlfcn_bind_var(DSO *dso, const char *symname);
static DSO_FUNC_TYPE dlfcn_bind_func(DSO *dso, const char *symname);
# if 0
static int dlfcn_unbind(DSO *dso, char *symname, void *symptr);
static int dlfcn_init(DSO *dso);
static int dlfcn_finish(DSO *dso);
static long dlfcn_ctrl(DSO *dso, int cmd, long larg, void *parg);
# endif
static char *dlfcn_name_converter(DSO *dso, const char *filename);
static char *dlfcn_merger(DSO *dso, const char *filespec1,
                          const char *filespec2);

static DSO_METHOD dso_meth_dlfcn = {
    "OpenSSL 'dlfcn' shared library method",
    dlfcn_load,
    dlfcn_unload,
    dlfcn_bind_var,
    dlfcn_bind_func,
/* For now, "unbind" doesn't exist */
# if 0
    NULL,                       /* unbind_var */
    NULL,                       /* unbind_func */
# endif
    NULL,                       /* ctrl */
    dlfcn_name_converter,
    dlfcn_merger,
    NULL,                       /* init */
    NULL                        /* finish */
};

DSO_METHOD *DSO_METHOD_dlfcn(void)
{
    return (&dso_meth_dlfcn);
}

/*
 * Prior to using the dlopen() function, we should decide on the flag we
 * send. There's a few different ways of doing this and it's a messy
 * venn-diagram to match up which platforms support what. So as we don't have
 * autoconf yet, I'm implementing a hack that could be hacked further
 * relatively easily to deal with cases as we find them. Initially this is to
 * cope with OpenBSD.
 */
# if defined(__OpenBSD__) || defined(__NetBSD__)
#  ifdef DL_LAZY
#   define DLOPEN_FLAG DL_LAZY
#  else
#   ifdef RTLD_NOW
#    define DLOPEN_FLAG RTLD_NOW
#   else
#    define DLOPEN_FLAG 0
#   endif
#  endif
# else
#  ifdef OPENSSL_SYS_SUNOS
#   define DLOPEN_FLAG 1
#  else
#   define DLOPEN_FLAG RTLD_NOW /* Hope this works everywhere else */
#  endif
# endif

/*
 * For this DSO_METHOD, our meth_data STACK will contain; (i) the handle
 * (void*) returned from dlopen().
 */

static int dlfcn_load(DSO *dso)
{
    void *ptr = NULL;
    /* See applicable comments in dso_dl.c */
    char *filename = DSO_convert_filename(dso, NULL);
    int flags = DLOPEN_FLAG;

    if (filename == NULL) {
        DSOerr(DSO_F_DLFCN_LOAD, DSO_R_NO_FILENAME);
        goto err;
    }
# ifdef RTLD_GLOBAL
    if (dso->flags & DSO_FLAG_GLOBAL_SYMBOLS)
        flags |= RTLD_GLOBAL;
# endif
    ptr = dlopen(filename, flags);
    if (ptr == NULL) {
        DSOerr(DSO_F_DLFCN_LOAD, DSO_R_LOAD_FAILED);
        ERR_add_error_data(4, "filename(", filename, "): ", dlerror());
        goto err;
    }
    if (!sk_push(dso->meth_data, (char *)ptr)) {
        DSOerr(DSO_F_DLFCN_LOAD, DSO_R_STACK_ERROR);
        goto err;
    }
    /* Success */
    dso->loaded_filename = filename;
    return (1);
 err:
    /* Cleanup! */
    if (filename != NULL)
        OPENSSL_free(filename);
    if (ptr != NULL)
        dlclose(ptr);
    return (0);
}

static int dlfcn_unload(DSO *dso)
{
    void *ptr;
    if (dso == NULL) {
        DSOerr(DSO_F_DLFCN_UNLOAD, ERR_R_PASSED_NULL_PARAMETER);
        return (0);
    }
    if (sk_num(dso->meth_data) < 1)
        return (1);
    ptr = (void *)sk_pop(dso->meth_data);
    if (ptr == NULL) {
        DSOerr(DSO_F_DLFCN_UNLOAD, DSO_R_NULL_HANDLE);
        /*
         * Should push the value back onto the stack in case of a retry.
         */
        sk_push(dso->meth_data, (char *)ptr);
        return (0);
    }
    /* For now I'm not aware of any errors associated with dlclose() */
    dlclose(ptr);
    return (1);
}

static void *dlfcn_bind_var(DSO *dso, const char *symname)
{
    void *ptr, *sym;

    if ((dso == NULL) || (symname == NULL)) {
        DSOerr(DSO_F_DLFCN_BIND_VAR, ERR_R_PASSED_NULL_PARAMETER);
        return (NULL);
    }
    if (sk_num(dso->meth_data) < 1) {
        DSOerr(DSO_F_DLFCN_BIND_VAR, DSO_R_STACK_ERROR);
        return (NULL);
    }
    ptr = (void *)sk_value(dso->meth_data, sk_num(dso->meth_data) - 1);
    if (ptr == NULL) {
        DSOerr(DSO_F_DLFCN_BIND_VAR, DSO_R_NULL_HANDLE);
        return (NULL);
    }
    sym = dlsym(ptr, symname);
    if (sym == NULL) {
        DSOerr(DSO_F_DLFCN_BIND_VAR, DSO_R_SYM_FAILURE);
        ERR_add_error_data(4, "symname(", symname, "): ", dlerror());
        return (NULL);
    }
    return (sym);
}

static DSO_FUNC_TYPE dlfcn_bind_func(DSO *dso, const char *symname)
{
    void *ptr;
    union {
        DSO_FUNC_TYPE sym;
        void *dlret;
    } u;

    if ((dso == NULL) || (symname == NULL)) {
        DSOerr(DSO_F_DLFCN_BIND_FUNC, ERR_R_PASSED_NULL_PARAMETER);
        return (NULL);
    }
    if (sk_num(dso->meth_data) < 1) {
        DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_STACK_ERROR);
        return (NULL);
    }
    ptr = (void *)sk_value(dso->meth_data, sk_num(dso->meth_data) - 1);
    if (ptr == NULL) {
        DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_NULL_HANDLE);
        return (NULL);
    }
    u.dlret = dlsym(ptr, symname);
    if (u.dlret == NULL) {
        DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_SYM_FAILURE);
        ERR_add_error_data(4, "symname(", symname, "): ", dlerror());
        return (NULL);
    }
    return u.sym;
}

static char *dlfcn_merger(DSO *dso, const char *filespec1,
                          const char *filespec2)
{
    char *merged;

    if (!filespec1 && !filespec2) {
        DSOerr(DSO_F_DLFCN_MERGER, ERR_R_PASSED_NULL_PARAMETER);
        return (NULL);
    }
    /*
     * If the first file specification is a rooted path, it rules. same goes
     * if the second file specification is missing.
     */
    if (!filespec2 || filespec1[0] == '/') {
        merged = OPENSSL_malloc(strlen(filespec1) + 1);
        if (!merged) {
            DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
            return (NULL);
        }
        strcpy(merged, filespec1);
    }
    /*
     * If the first file specification is missing, the second one rules.
     */
    else if (!filespec1) {
        merged = OPENSSL_malloc(strlen(filespec2) + 1);
        if (!merged) {
            DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
            return (NULL);
        }
        strcpy(merged, filespec2);
    } else
        /*
         * This part isn't as trivial as it looks.  It assumes that the
         * second file specification really is a directory, and makes no
         * checks whatsoever.  Therefore, the result becomes the
         * concatenation of filespec2 followed by a slash followed by
         * filespec1.
         */
    {
        int spec2len, len;

        spec2len = (filespec2 ? strlen(filespec2) : 0);
        len = spec2len + (filespec1 ? strlen(filespec1) : 0);

        if (filespec2 && filespec2[spec2len - 1] == '/') {
            spec2len--;
            len--;
        }
        merged = OPENSSL_malloc(len + 2);
        if (!merged) {
            DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
            return (NULL);
        }
        strcpy(merged, filespec2);
        merged[spec2len] = '/';
        strcpy(&merged[spec2len + 1], filespec1);
    }
    return (merged);
}

# ifdef OPENSSL_SYS_MACOSX
#  define DSO_ext ".dylib"
#  define DSO_extlen 6
# else
#  define DSO_ext ".so"
#  define DSO_extlen 3
# endif

static char *dlfcn_name_converter(DSO *dso, const char *filename)
{
    char *translated;
    int len, rsize, transform;

    len = strlen(filename);
    rsize = len + 1;
    transform = (strstr(filename, "/") == NULL);
    if (transform) {
        /* We will convert this to "%s.so" or "lib%s.so" etc */
        rsize += DSO_extlen;    /* The length of ".so" */
        if ((DSO_flags(dso) & DSO_FLAG_NAME_TRANSLATION_EXT_ONLY) == 0)
            rsize += 3;         /* The length of "lib" */
    }
    translated = OPENSSL_malloc(rsize);
    if (translated == NULL) {
        DSOerr(DSO_F_DLFCN_NAME_CONVERTER, DSO_R_NAME_TRANSLATION_FAILED);
        return (NULL);
    }
    if (transform) {
        if ((DSO_flags(dso) & DSO_FLAG_NAME_TRANSLATION_EXT_ONLY) == 0)
            sprintf(translated, "lib%s" DSO_ext, filename);
        else
            sprintf(translated, "%s" DSO_ext, filename);
    } else
        sprintf(translated, "%s", filename);
    return (translated);
}

#endif                          /* DSO_DLFCN */