/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * System Use Sharing protocol subroutines for High Sierra filesystem
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/disp.h>
#include <sys/buf.h>
#include <sys/pathname.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/conf.h>

#include <vm/page.h>

#include <sys/fs/hsfs_spec.h>
#include <sys/fs/hsfs_isospec.h>
#include <sys/fs/hsfs_node.h>
#include <sys/fs/hsfs_impl.h>
#include <sys/fs/hsfs_susp.h>
#include <sys/fs/hsfs_rrip.h>

#include <sys/statvfs.h>
#include <sys/mount.h>
#include <sys/swap.h>
#include <sys/errno.h>
#include <sys/debug.h>
#include "fs/fs_subr.h"
#include <sys/cmn_err.h>

/* static declarations */
static void free_cont_area(uchar_t *);
static int get_cont_area(struct hsfs *, uchar_t **, cont_info_t *);
static int parse_signatures(sig_args_t *, int, uchar_t *, int);

/*
 * parse_sua()
 *
 * This is the main SUSP routine, that gets all the SUA areas and
 * continuations.       It calls parse_signatures() to actually interpret
 * the signature fields.
 *
 * XXX - need to implement signature searching to speed things up and
 *              which is needed for the api, which isn't done yet.
 */
int
parse_sua(
        uchar_t                 *name_p,        /* location to copy name */
        int                     *name_len_p,    /* location to put name len */
        int                     *name_change_p, /* flags to signal name chg */
        uchar_t                 *dirp,          /* pointer to ISO dir entry */
        uint_t                  last_offset,    /* last ind. in cur. dirblock */
        struct hs_direntry      *hdp,           /* loc to store dir info */
        struct hsfs             *fsp,           /* filesystem pointer */
        uchar_t                 *search_sig,    /* signature to search for */
        int                     search_num)     /* n^th sig to search for */
{
        uchar_t                 *SUA_p = IDE_sys_use_area(dirp);
        int                     SUA_len = IDE_SUA_LEN(dirp);
        uchar_t                 *tmp_SUA_p = (SUA_p + fsp->hsfs_sua_off);
        int                     tmp_SUA_len = (SUA_len - fsp->hsfs_sua_off);
        short                   ret_val = -1;
        uchar_t                 *cont_p = (uchar_t *)NULL;
        sig_args_t              sig_args;
        cont_info_t             cont_info;

        /*
         * If there is no SUA, just return, no error
         */

        if (SUA_len == 0)
                return (0);

        /*
         * Underflow on the length field means there's a mismatch
         * between sizes of SUA and ISO directory entry. This entry
         * is corrupted, return an appropriate error.
         */
        if (SUA_len < 0) {
                hs_log_bogus_disk_warning(fsp, HSFS_ERR_NEG_SUA_LEN, 0);
                return (SUA_EINVAL);
        }

        if ((tmp_SUA_p + tmp_SUA_len) > (dirp + last_offset)) {
                hs_log_bogus_disk_warning(fsp, HSFS_ERR_BAD_SUA_LEN, 0);
                return (SUA_EINVAL);
        }

        /*
         * Make sure that the continuation lenth is zero, as that is
         * the way to tell if we must grab another continuation area.
         */
        bzero((char *)&cont_info, sizeof (cont_info));

        sig_args.dirp           = dirp;
        sig_args.name_p         = name_p;
        sig_args.name_len_p     = name_len_p;
        sig_args.SUF_ptr        = tmp_SUA_p;
        sig_args.hdp            = hdp;
        sig_args.fsp            = fsp;
        sig_args.cont_info_p    = &cont_info;
        sig_args.flags          = 0;
        sig_args.name_flags     = 0;

        /*
         * Get ready to put in a new name.       If no "NM" is found, then
         * hs_namecopy will come to the rescue.  Make sure you don't
         * have NULL names, also.
         */
        if (name_p)
                *(name_p) = '\0';
        if (name_len_p)
                *(name_len_p) = 0;

        while (ret_val == -1) {
                switch (parse_signatures(&sig_args, tmp_SUA_len, search_sig,
                    search_num)) {
                case END_OF_SUA :
                        if (cont_info.cont_len) {

                                if (get_cont_area(fsp, &cont_p, &cont_info)) {
                                        ret_val = 1;
                                        goto clean_up;
                                }

                                sig_args.SUF_ptr =
                                    cont_p + cont_info.cont_offset;

                                tmp_SUA_len = cont_info.cont_len;
                                cont_info.cont_len = 0;

                                continue;
                        }
                        sig_args.flags = 0;     /* reset */
                        ret_val = 0;            /* keep going */
                        break;
                case SUA_NULL_POINTER:
                        ret_val = SUA_NULL_POINTER;
                        goto clean_up;
                case SUA_ENOMEM:
                        ret_val = SUA_ENOMEM;
                        goto clean_up;
                case SUA_EINVAL:
                        ret_val = SUA_EINVAL;
                        goto clean_up;
                case RELOC_DIR:
                        ret_val = RELOC_DIR;
                        goto clean_up;
                }
        }

        if (ret_val != 0)
                goto clean_up;

        if (IS_NAME_BIT_SET(sig_args.name_flags, RRIP_NAME_CHANGE))
                SET_NAME_BIT(*(name_change_p), RRIP_NAME_CHANGE);

clean_up:
        free_cont_area(cont_p);
        return (ret_val);

}

/*
 * parse_signatures()
 *
 * Find the correct handling function for the signature string that is
 * passed to this function.
 *
 * signature searching:
 *
 * The two arguments of search_sig and search_num are for finding the
 * search_num^th occurance of the signature search_sig.  This will come
 * in handy with searching for the "NM" field and is part of the api
 * for rrip (which really can be used for any extension).
 */
/*ARGSUSED*/
static int
parse_signatures(
        sig_args_t      *sig_args_p,
        int             SUA_len,
        uchar_t         *search_sig,    /* possible signature to search for */
        int             search_num)     /* n^th occurance of search_sig to */
                                        /*   search for */
{
        uchar_t                 *sig_string = sig_args_p->SUF_ptr;
        extension_name_t        *extnp;
        ext_signature_t         *ext_sigp;
        int                     impl_bit_num = 0;
        int                     SUA_rem = SUA_len; /* SUA length */
                                        /* remaining to be parsed */

        /* This should never happen ... just so we don't panic, literally */
        if (sig_string == (uchar_t *)NULL)
                return (SUA_NULL_POINTER);

        if (SUA_len < 0)
                return (SUA_EINVAL);

        /*
         * Until the end of SUA, search for the signatures
         * (check for end of SUA (2 consecutive NULL bytes)) or the
         * remaining  length of the SUA is <= 3.  The minimum signature
         * field  is 4.
         */

        while ((SUA_rem >= SUF_MIN_LEN) && (*sig_string != '\0') &&
                (*(sig_string + 1) != '\0')) {

                /*
                 * Find appropriate extension and signature table
                 */
                for (extnp = extension_name_table, impl_bit_num = 0;
                    extnp->extension_name != (char *)NULL;
                    extnp++, impl_bit_num++)  {

                        /*
                         * look at an extension only if it is implemented
                         * on the CD-ROM
                         */
                        if (!IS_IMPL_BIT_SET(sig_args_p->fsp, impl_bit_num))
                                continue;

                        /*
                         * Find the appropriate signature
                         */
                        for (ext_sigp = extnp->signature_table;
                            ext_sigp->ext_signature != (char *)NULL;
                            ext_sigp++)  {

                                if (strncmp((char *)sig_string,
                                            ext_sigp->ext_signature,
                                            SUF_SIG_LEN) == 0) {

                                        SUA_rem -= SUF_LEN(sig_string);
                                        if (SUA_rem < 0)
                                                return (END_OF_SUA);

                                        /*
                                         * The SUA_len parameter specifies the
                                         * length of the SUA that the kernel
                                         * expects. There is also a length
                                         * encoded in the SUA data. If they
                                         * do not agree, bail out.
                                         */
                                        if (SUA_len < SUF_LEN(sig_string)) {
                                                cmn_err(CE_NOTE,
                                        "parse_signatures: SUA length too big: "
                                        "expected=%d, found=%d",
                                                    SUA_len,
                                                    SUF_LEN(sig_string));
                                                return (SUA_EINVAL);
                                        }

                                        sig_args_p->SUF_ptr = sig_string;
                                        sig_string =
                                            (ext_sigp->sig_handler)(sig_args_p);

                                        switch (sig_args_p->flags) {
                                        case END_OF_SUA :
                                                return (END_OF_SUA);
                                        case SUA_ENOMEM :
                                                return (SUA_ENOMEM);
                                        case SUA_EINVAL :
                                                return (SUA_EINVAL);
                                        case RELOC_DIR :
                                                return (RELOC_DIR);
                                        default :
#if NAME_SEARCH
                                                case NAME_CONTINUE :
                                                        /* nothing for now */
                                                case NAME_CHANGE :
                                                        /* nothing for now */
#endif
                                                break;
                                        }

                                        /* reset to be zero */

                                        sig_args_p->flags = 0;
                                        goto next_signature;
                                }

                                /* off to the next signature .... */

                        } /* for ext_sigp */

                } /* for extnp  (extension parsing) */

                /*
                 * Opps, did not find this signature. We must
                 * advance on the the next signature in the SUA
                 * and pray to persumedly omniscient, omnipresent,
                 * almighty transcendental being(s) that the next
                 * record is in the susp format, or we get hosed.
                 */
                if (SUA_rem < SUF_MIN_LEN)
                        return (END_OF_SUA);

                SUA_rem -= SUF_LEN(sig_string);
                sig_string += SUF_LEN(sig_string);

next_signature:
                /*
                 * Failsafe
                 */
                if (SUA_rem < SUF_MIN_LEN ||
                    sig_string == NULL || SUF_LEN(sig_string) <= 0) {
                        return (END_OF_SUA);
                }

        } /* while */

        return (END_OF_SUA);
}

/*
 * hs_fill_root_dirent()
 *
 *
 * This function reads the root directory extent to get to the SUA of
 * the "." entry of the root directory.  It the checks to see if the
 * susp is implemented.
 */
void
hs_check_root_dirent(struct vnode *vp, struct hs_direntry *hdp)
{
        struct buf      *secbp;
        uchar_t         *root_ptr;
        uchar_t         *secp;
        uint_t          secno;
        offset_t        secoff;
        sig_args_t      sig_args;
        struct hsfs     *fsp;
        int             error;

        if (vp->v_type != VDIR) {
                cmn_err(CE_NOTE,
                    "hs_check_root_dirent: vp (0x%p) not a directory",
                    (void *)vp);
                return;
        }

        bzero((caddr_t)&sig_args, sizeof (sig_args));

        fsp = VFS_TO_HSFS(vp->v_vfsp);
        secno = LBN_TO_SEC(hdp->ext_lbn+hdp->xar_len, vp->v_vfsp);
        secoff = LBN_TO_BYTE(hdp->ext_lbn+hdp->xar_len, vp->v_vfsp) &
            MAXHSOFFSET;
        secbp = bread(fsp->hsfs_devvp->v_rdev, secno * 4, HS_SECTOR_SIZE);
        error = geterror(secbp);

        if (error != 0) {
                cmn_err(CE_NOTE,
                    "hs_check_root_dirent: bread: error=(%d)", error);
                goto end;
        }

        secp = (uchar_t *)secbp->b_un.b_addr;
        root_ptr = &secp[secoff];

        /* quick check */
        if (hdp->ext_lbn != HDE_EXT_LBN(root_ptr)) {
                cmn_err(CE_NOTE, "hs_check_root_dirent: dirent not match\n");
                /* keep on going */
        }

        /*
         * Here, we know that the "." entry is the first in the sector
         * just read (ISO 9660).  Let's now check for the sharing
         * protocol and set call the susp sig_handler() if we should.
         * Then we run through the hs_parsedir() function to catch all
         * the other possibilities of SUSP fields and continuations.
         *
         * If there is no SUA area, just return, and assume ISO.
         *
         * If the SUA area length is invalid (negative, due to a mismatch
         * between dirent size and SUA size), return and hope for the best.
         */

        if (IDE_SUA_LEN(root_ptr) <= 0)
                goto end;

        if (strncmp(SUSP_SP, (char *)IDE_sys_use_area(root_ptr),
            SUF_SIG_LEN) == 0) {
                /*
                 * We have a match of the sharing signature, so let's
                 * call the sig_handler to do what is necessary. We can
                 * ignore the return value, as implemented bits are set.
                 */
                sig_args.SUF_ptr = IDE_sys_use_area(root_ptr);
                sig_args.fsp     = fsp;

                if ((susp_sp->sig_handler)(&sig_args) == (uchar_t *)NULL) {
                        goto end;
                }
        } else {
                goto end;
        }

        /*
         * If the "ER" signature in the root directory is past any non SU
         * signature, the Rock Ridge signatures will be ignored. This happens
         * e.g. for filesystems created by mkisofs. In this case,
         * IS_RRIP_IMPLEMENTED(fsp) will return 0 when the "ER" signature is
         * parsed. Unfortunately, the results of this run will be cached for
         * the root vnode. The solution is to run hs_parsedir() a second time
         * for the root directory.
         */
        if (hs_parsedir(fsp, root_ptr, hdp, (char *)NULL, (int *)NULL,
            HS_SECTOR_SIZE - secoff) == 0) {
                (void) hs_parsedir(fsp, root_ptr, hdp, (char *)NULL,
                    (int *)NULL, HS_SECTOR_SIZE - secoff);
        }

        /*
         * If we did not get at least 1 extension, let's assume ISO and
         * NULL out the implementation bits.
         */
        if (fsp->hsfs_ext_impl <= 1L)
                fsp->hsfs_ext_impl = 0L;

end:
        brelse(secbp);
}


/*
 * get_cont_area()
 *
 * This function allocates a memory block, if necessary, and reads the
 * continuation area into the allocated space.
 *
 * Return value :       0 if the read and allocation went OK.
 *                      1 if there was an error.
 */
static int
get_cont_area(struct hsfs *fsp, uchar_t **buf_pp, cont_info_t *cont_info_p)
{
        struct buf      *secbp;
        int             error;
        uint_t          secno;

        /*
         * Guard against invalid continuation area records.
         * Both cont_offset and cont_len must be no longer than
         * HS_SECTOR_SIZE. If they are, return an error.
         */
        if (cont_info_p->cont_offset > HS_SECTOR_SIZE ||
            cont_info_p->cont_len > HS_SECTOR_SIZE) {
                cmn_err(CE_NOTE, "get_cont_area: invalid offset/length");
                return (1);
        }

        if (*buf_pp == (uchar_t *)NULL)
                *buf_pp = kmem_alloc((size_t)HS_SECTOR_SIZE, KM_SLEEP);

        secno = (uint_t)LBN_TO_SEC(cont_info_p->cont_lbn, fsp->hsfs_vfs);
        secbp = bread(fsp->hsfs_devvp->v_rdev, secno * 4, HS_SECTOR_SIZE);
        error = geterror(secbp);

        if (error != 0) {
                cmn_err(CE_NOTE, "get_cont_area: bread: error=(%d)", error);
                brelse(secbp);
                return (1);
        }

        /*
         * This continuation area does not extend into the next sector
         * so just copy the data to the buffer.
         */
        if ((cont_info_p->cont_offset + cont_info_p->cont_len) <=
            HS_SECTOR_SIZE) {
                bcopy(secbp->b_un.b_addr, (char *)*buf_pp, HS_SECTOR_SIZE);
        }
        /*
         * This continuation area extends into the next sector so we
         * need to do some dancing:
         *
         * - zero the return buffer so nothing random is returned
         * - copy the partial data to the *beginning* of the return buffer
         * - release the first sector's buffer
         * - read the next sector
         * - copy the remainder of the data to the return buffer
         */
        else {
                uint_t  partial_size;

                bzero((char *)*buf_pp, HS_SECTOR_SIZE);
                partial_size = HS_SECTOR_SIZE - cont_info_p->cont_offset;
                bcopy(&secbp->b_un.b_addr[cont_info_p->cont_offset],
                    (char *)*buf_pp, partial_size);
                cont_info_p->cont_offset = 0;
                brelse(secbp);

                secbp = bread(fsp->hsfs_devvp->v_rdev, (secno + 1) * 4,
                    HS_SECTOR_SIZE);
                error = geterror(secbp);
                if (error != 0) {
                        cmn_err(CE_NOTE, "get_cont_area: bread(2): error=(%d)",
                            error);
                        brelse(secbp);
                        return (1);
                }
                bcopy(secbp->b_un.b_addr, (char *)&(*buf_pp)[partial_size],
                    cont_info_p->cont_len - partial_size);
        }

        brelse(secbp);
        return (0);
}


/*
 * free_cont_area
 *
 * simple function to just free up memory, if it exists
 *
 */
static void
free_cont_area(uchar_t *cont_p)
{
        if (cont_p)
                (void) kmem_free((caddr_t)cont_p, (size_t)HS_SECTOR_SIZE);
        cont_p = (uchar_t *)NULL;
}