/* * $Id: cap_extint.c,v 1.1 2003/01/03 02:16:17 jwm Exp $ * * Copyright (c) 1997-8 Andrew G Morgan <morgan@linux.kernel.org> * * See end of file for Log. * * This file deals with exchanging internal and external * representations of capability sets. */#include "libcap.h"/* * External representation for capabilities. (exported as a fixed * length (void *)) */#define CAP_EXT_MAGIC "\220\302\001\121"#define CAP_EXT_MAGIC_SIZE 4const static __u8 external_magic[CAP_EXT_MAGIC_SIZE+1] = CAP_EXT_MAGIC;struct cap_ext_struct {    __u8 magic[CAP_EXT_MAGIC_SIZE];    __u8 length_of_capset;/* note, we arrange these so the caps are stacked with byte-size   resolution */    __u8 bytes[CAP_SET_SIZE][NUMBER_OF_CAP_SETS];};/* * return size of external capability set */ssize_t cap_size(cap_t caps){    return sizeof(struct cap_ext_struct);}/* * Copy the internal (cap_d) capability set into an external * representation.  The external representation is portable to other * Linux architectures. */ssize_t cap_copy_ext(void *cap_ext, cap_t cap_d, ssize_t length){    struct cap_ext_struct *result = (struct cap_ext_struct *) cap_ext;    __u32 *from = (__u32 *) &(cap_d->set);    int i;    /* valid arguments? */    if (!good_cap_t(cap_d) || length < sizeof(struct cap_ext_struct)	|| cap_ext == NULL) {	errno = EINVAL;	return -1;    }    /* fill external capability set */    memcpy(&result->magic, external_magic, CAP_EXT_MAGIC_SIZE);    result->length_of_capset = CAP_SET_SIZE;    for (i=0; i<NUMBER_OF_CAP_SETS; ++i) {	int j;	for (j=0; j<CAP_SET_SIZE; ) {	    __u32 val = *from++;	    result->bytes[j++][i] =  val        & 0xFF;	    result->bytes[j++][i] = (val >>= 8) & 0xFF;	    result->bytes[j++][i] = (val >>= 8) & 0xFF;	    result->bytes[j++][i] = (val >> 8)  & 0xFF;	}    }    /* All done: return length of external representation */    return (sizeof(struct cap_ext_struct));}/* * Import an external representation to produce an internal rep. * the internal rep should be liberated with cap_free(). *//* * XXX - need to take a little more care when importing small * capability sets. */cap_t cap_copy_int(const void *cap_ext){    const struct cap_ext_struct *export =	(const struct cap_ext_struct *) cap_ext;    cap_t cap_d = NULL;    int set, blen;    __u32 * to = (__u32 *) &cap_d->set;    /* Does the external representation make sense? */    if (export == NULL || !memcmp(export->magic, external_magic				  , CAP_EXT_MAGIC_SIZE)) {	errno = EINVAL;	return NULL;    }    /* Obtain a new internal capability set */    if (!(cap_d = cap_init()))       return NULL;    blen = export->length_of_capset;    for (set=0; set<=NUMBER_OF_CAP_SETS; ++set) {	int blk;	int bno = 0;	for (blk=0; blk<(CAP_SET_SIZE/4); ++blk) {	    __u32 val = 0;	    if (bno != blen)		val  = export->bytes[bno++][set];	    if (bno != blen)		val |= export->bytes[bno++][set] << 8;	    if (bno != blen)		val |= export->bytes[bno++][set] << 16;	    if (bno != blen)		val |= export->bytes[bno++][set] << 24;	    *to++ = val;	}    }    /* all done */    return cap_d;}/* * $Log: cap_extint.c,v $ * Revision 1.1  2003/01/03 02:16:17  jwm * * Turning mod_linuxprivs into a core module, mod_cap. This is by no means * complete. * * Revision 1.3  1999/09/17 03:54:08  macgyver * Corrected gcc warning. * * Revision 1.2  1999/09/07 23:14:19  macgyver * Updated capabilities library and model. * * Revision 1.1.1.1  1999/04/17 22:16:31  morgan * release 1.0 of libcap * * Revision 1.3  1998/05/24 22:54:09  morgan * updated for 2.1.104 * * Revision 1.2  1997/04/28 00:57:11  morgan * fixes and zefram's patches * * Revision 1.1  1997/04/21 04:32:52  morgan * Initial revision * */