/* #ident  "@(#)g_initialize.c 1.2     96/02/06 SMI" */

/*
 * Copyright 1996 by Sun Microsystems, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of Sun Microsystems not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. Sun Microsystems makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * SUN MICROSYSTEMS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL SUN MICROSYSTEMS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * This function will initialize the gssapi mechglue library
 */

#include "config.h"
#include "mglueP.h"
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#ifdef USE_SOLARIS_SHARED_LIBRARIES
#include <dlfcn.h>

#define MECH_CONF "/etc/mech.conf"
#define MECH_SYM "gss_mech_initialize"

static void solaris_initialize (void);
#endif /* USE_SOLARIS_SHARED_LIBRARIES */

#ifdef __linux__
#define USE_LINUX_SHARED_LIBRARIES
#endif

#ifdef USE_LINUX_SHARED_LIBRARIES
#include <dlfcn.h>
#define MECH_CONF "/etc/gssapi_mech.conf"
#define MECH_SYM "gss_mech_initialize"
static void linux_initialize (void);
#endif /* USE_LINUX_SHARED_LIBRARIES */

#define g_OID_equal(o1,o2) \
   (((o1)->length == (o2)->length) && \
    (memcmp((o1)->elements,(o2)->elements,(int) (o1)->length) == 0))

extern gss_mechanism krb5_gss_initialize();

static int _gss_initialized = 0;

static struct gss_config null_mech = {
  {0,NULL}};

gss_mechanism *__gss_mechs_array = NULL;

/*
 * This function will add a new mechanism to the mechs_array
 */

static OM_uint32
add_mechanism (mech, replace)
     gss_mechanism mech;
     int replace;
{
    gss_mechanism *	temp_array;
    gss_OID_set		mech_names;
    OM_uint32		minor_status, major_status;
    unsigned int 	i;

    if (mech == NULL)
	return GSS_S_COMPLETE;

    /* initialize the mechs_array if it hasn't already been initialized */
    if (__gss_mechs_array == NULL) {
	__gss_mechs_array = (gss_mechanism *) malloc (sizeof(gss_mechanism));

	if (__gss_mechs_array == NULL)
	    return ENOMEM;

	__gss_mechs_array[0] = &null_mech;
    }

    /*
     * Find the length of __gss_mechs_array, and look for an existing
     * entry for this OID
     */
    for (i=0; __gss_mechs_array[i]->mech_type.length != 0; i++) {
	if (!g_OID_equal(&__gss_mechs_array[i]->mech_type,
			 &mech->mech_type))
	    continue;

	/* We found a match.  Replace it? */
	if (!replace)
	    return GSS_S_FAILURE;

	__gss_mechs_array[i] = mech;
	return GSS_S_COMPLETE;
    }

    /* we didn't find it -- add it to the end of the __gss_mechs_array */
    temp_array = (gss_mechanism *) realloc(__gss_mechs_array,
					   (i+2)*sizeof(gss_mechanism));

    if (temp_array == NULL)
	return ENOMEM;

    temp_array[i++] = mech;
    temp_array[i] = &null_mech;

    __gss_mechs_array = temp_array;

    /*
     * OK, now let's register all of the name types this mechanism
     * knows how to deal with.
     */
    major_status = gss_inquire_names_for_mech(&minor_status, &mech->mech_type,
					      &mech_names);
    if (major_status != GSS_S_COMPLETE)
	return (GSS_S_COMPLETE);
    for (i=0; i < mech_names->count; i++) {
	gss_add_mech_name_type(&minor_status, &mech_names->elements[i],
			       &mech->mech_type);
    }
    (void) gss_release_oid_set(&minor_status, &mech_names);

    return GSS_S_COMPLETE;
}

void gss_initialize ()
{
    /* Make sure we've not run already */
    if (_gss_initialized)
	return;
    _gss_initialized = 1;

#ifdef USE_SOLARIS_SHARED_LIBRARIES
    solaris_initialize();

#elif defined(USE_LINUX_SHARED_LIBRARIES)
    linux_initialize();

#else
    {
	gss_mechanism mech;

	/*
	 * Use hard-coded in mechanisms...  I need to know what mechanisms
	 * are supported...  As more mechanisms become supported, they
	 * should be added here, unless shared libraries are used.
	 */

	/* Initialize the krb5 mechanism */
	mech = (gss_mechanism)krb5_gss_initialize();
	if (mech)
	    add_mechanism (mech, 1);
    }

#endif /* USE_SOLARIS_SHARED_LIBRARIES */

#if !defined(macintosh)
    if (__gss_mechs_array == NULL) { /* this is very bad! */
      fprintf(stderr,"gss_initialize fatal error: no mechanisms loaded!\n");
      exit(-1);
    }
#else
    /*
     * Nothing for now, since this should never happen using static
     * mechanism loading.
     */
#endif

    return;
}

#ifdef USE_SOLARIS_SHARED_LIBRARIES
/*
 * read the configuration file to find out what mechanisms to
 * load, load them, and then load the mechanism defitions in
 * and add the mechanisms
 */
static void solaris_initialize ()
{
    char buffer[BUFSIZ], *filename, *symname, *endp;
    FILE *conffile;
    void *dl;
    gss_mechanism (*sym)(void), mech;

    if ((filename = getenv("GSSAPI_MECH_CONF")) == NULL)
	filename = MECH_CONF;

    if ((conffile = fopen(filename, "r")) == NULL) {
		fprintf(stderr,"fatal error: unable to open %s:"
			" errno %d (%s)\n", filename, errno, strerror(errno));
		return;
    }

    while (fgets (buffer, BUFSIZ, conffile) != NULL) {
	/* ignore lines beginning with # */
	if (*buffer == '#')
	    continue;

	/* find the first white-space character after the filename */
	for (symname = buffer; *symname && !isspace(*symname); symname++);

	/* Now find the first non-white-space character */
	if (*symname) {
	    *symname = '\0';
	    symname++;
	    while (*symname && isspace(*symname))
		symname++;
	}

	if (! *symname)
	    symname = MECH_SYM;
	else {
	  /* Find the end of the symname and make sure it is NULL-terminated */
	  for (endp = symname; *endp && !isspace(*endp); endp++);
	  if (*endp)
	    *endp = '\0';
	}

	if ((dl = dlopen(buffer, RTLD_NOW)) == NULL) {
		/* for debugging only */
		fprintf(stderr,"can't open %s: %s\n",buffer, dlerror());
		continue;
	}

	if ((sym = (gss_mechanism (*)(void))dlsym(dl, symname)) == NULL) {
	    dlclose(dl);
	    continue;
	}

	/* Call the symbol to get the mechanism table */
	mech = sym();

	/* And add the mechanism (or close the shared library) */
	if (mech)
	    add_mechanism (mech, 1);
	else
	    dlclose(dl);

    } /* while */

    return;
}
#endif /* USE_SOLARIS_SHARED_LIBRARIES */

#ifdef USE_LINUX_SHARED_LIBRARIES
extern gss_mechanism internal_krb5_gss_initialize(void *dl);

/*
 * read the configuration file to find out what mechanisms to
 * load, load them, and then load the mechanism defitions in
 * and add the mechanisms
 */
static void linux_initialize ()
{
    char buffer[BUFSIZ], *filename, *symname, *endp, *err_string;
    FILE *conffile;
    void *dl;
    gss_mechanism (*sym)(void), mech;

    if ((filename = getenv("GSSAPI_MECH_CONF")) == NULL)
	filename = MECH_CONF;

    if ((conffile = fopen(filename, "r")) == NULL) {
		fprintf(stderr,"fatal error: unable to open %s:"
			" errno %d (%s)\n", filename, errno, strerror(errno));
		return;
    }

    while (fgets (buffer, BUFSIZ, conffile) != NULL) {
	/* ignore lines beginning with # */
	if (*buffer == '#')
	    continue;

	/* find the first white-space character after the filename */
	for (symname = buffer; *symname && !isspace(*symname); symname++);

	/* Now find the first non-white-space character */
	if (*symname) {
	    *symname = '\0';
	    symname++;
	    while (*symname && isspace(*symname))
		symname++;
	}

	if (! *symname)
	    symname = MECH_SYM;
	else {
	    /* Find the end of the symname and make sure it is
	     * NULL-terminated */
	    for (endp = symname; *endp && !isspace(*endp); endp++);
	    if (*endp)
		*endp = '\0';
	}

	if ((dl = dlopen(buffer, RTLD_NOW)) == NULL) {
	    /* for debugging only */
	    fprintf(stderr,"can't open %s: %s\n",buffer, dlerror());
	    continue;
	}

#if defined(HAVE_KRB5) && defined(HAVE_HEIMDAL)
#error Should not have both HAVE_KRB5 and HAVE_HEIMDAL defined!!
#endif

#ifdef HAVE_KRB5
	/* Special case for dealing with MIT krb5 mechanism */
	if (strcmp(symname, "mechglue_internal_krb5_init") == 0) {
#ifdef DEBUG
	    fprintf(stderr, "Using special MIT initialization\n");
#endif
	    mech = internal_krb5_gss_initialize(dl);
	}
	else
#endif

#ifdef HAVE_HEIMDAL
	/* Special case for dealing with heimdal krb5 mechanism */
	if (strcmp(symname, "mechglue_internal_heimdal_init") == 0) {
#ifdef DEBUG
	    fprintf(stderr, "Using special Heimdal initialization\n");
#endif
	    mech = internal_heimdal_gss_initialize(dl);
	}
	else
#endif
	{
	    if ((sym = (gss_mechanism (*)(void))dlsym(dl, symname)) == NULL) {
		if ((err_string = dlerror()) != NULL) {
		    fprintf(stderr, "%s: searching for symbol '%s' in '%s'\n",
			    err_string, symname, buffer);
		    dlclose(dl);
		}
		continue;
	    }

	    /* Call the symbol to get the mechanism table */
	    mech = sym();
	}

	/* And add the mechanism (or close the shared library) */
	if (mech) {
#ifdef DEBUG
	    fprintf(stderr, "Adding mechanism for library '%s'\n", buffer);
#endif
	    add_mechanism (mech, 1);
	}
	else {
#ifdef DEBUG
	    fprintf(stderr,
		    "Failed to initialize mechanism for library '%s'\n",
		     buffer);
#endif
	    dlclose(dl);
	}

    } /* while */

    return;
}
#endif /* USE_LINUX_SHARED_LIBRARIES */