/* 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).
 *
 */

/* We need to do this early, because stdio.h includes the header files
   that handle _GNU_SOURCE and other similar macros.  Defining it later
   is simply too late, because those headers are protected from re-
   inclusion.  */
#ifdef __linux
# ifndef _GNU_SOURCE
#  define _GNU_SOURCE	/* make sure dladdr is declared */
# endif
#endif

#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 int dlfcn_pathbyaddr(void *addr,char *path,int sz);

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 */
	dlfcn_pathbyaddr
	};

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;
	DSO_FUNC_TYPE sym, *tsym = &sym;

	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);
		}
	*(void **)(tsym) = dlsym(ptr, symname);
	if(sym == NULL)
		{
		DSOerr(DSO_F_DLFCN_BIND_FUNC,DSO_R_SYM_FAILURE);
		ERR_add_error_data(4, "symname(", symname, "): ", dlerror());
		return(NULL);
		}
	return(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);
	}

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" */
		rsize += 3;	/* 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.so", filename);
		else
			sprintf(translated, "%s.so", filename);
		}
	else
		sprintf(translated, "%s", filename);
	return(translated);
	}

#ifdef __sgi
#if 0
This is a quote from IRIX manual for dladdr(3c):

     <dlfcn.h> does not contain a prototype for dladdr or definition of
     Dl_info.  The #include <dlfcn.h>  in the SYNOPSIS line is traditional,
     but contains no dladdr prototype and no IRIX library contains an
     implementation.  Write your own declaration based on the code below.

     The following code is dependent on internal interfaces that are not
     part of the IRIX compatibility guarantee; however, there is no future
     intention to change this interface, so on a practical level, the code
     below is safe to use on IRIX.
#endif
#include <rld_interface.h>
#ifndef _RLD_INTERFACE_DLFCN_H_DLADDR
#define _RLD_INTERFACE_DLFCN_H_DLADDR
typedef struct Dl_info {
    const char * dli_fname;
    void       * dli_fbase;
    const char * dli_sname;
    void       * dli_saddr;
    int          dli_version;
    int          dli_reserved1;
    long         dli_reserved[4];
} Dl_info;
#else
typedef struct Dl_info Dl_info;
#endif
#define _RLD_DLADDR             14

static int dladdr(void *address, Dl_info *dl)
{
	void *v;
	v = _rld_new_interface(_RLD_DLADDR,address,dl);
	return (int)v;
}
#endif

static int dlfcn_pathbyaddr(void *addr,char *path,int sz)
	{
	Dl_info dli;
	int len;

	if (addr == NULL)
		{
		union	{ int(*f)(void*,char*,int); void *p; } t =
			{ dlfcn_pathbyaddr };
		addr = t.p;
		}

	if (dladdr(addr,&dli))
		{
		len = (int)strlen(dli.dli_fname);
		if (sz <= 0) return len+1;
		if (len >= sz) len=sz-1;
		memcpy(path,dli.dli_fname,len);
		path[len++]=0;
		return len;
		}

	ERR_add_error_data(4, "dlfcn_pathbyaddr(): ", dlerror());
	return -1;
	}
#endif /* DSO_DLFCN */