source: vendor/current/source3/smbd/dfree.c

/* 
   Unix SMB/CIFS implementation.
   functions to calculate the free disk space
   Copyright (C) Andrew Tridgell 1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"

/****************************************************************************
 Normalise for DOS usage.
****************************************************************************/

static void disk_norm(uint64_t *bsize, uint64_t *dfree, uint64_t *dsize)
{
        /* check if the disk is beyond the max disk size */
        uint64_t maxdisksize = lp_max_disk_size();
        if (maxdisksize) {
                /* convert to blocks - and don't overflow */
                maxdisksize = ((maxdisksize*1024)/(*bsize))*1024;
                if (*dsize > maxdisksize) {
                        *dsize = maxdisksize;
                }
                if (*dfree > maxdisksize) {
                        *dfree = maxdisksize - 1;
                }
                /* the -1 should stop applications getting div by 0
                   errors */
        }
}



/****************************************************************************
 Return number of 1K blocks available on a path and total number.
****************************************************************************/

uint64_t sys_disk_free(connection_struct *conn, struct smb_filename *fname,
                       uint64_t *bsize, uint64_t *dfree, uint64_t *dsize)
{
        uint64_t dfree_retval;
        uint64_t dfree_q = 0;
        uint64_t bsize_q = 0;
        uint64_t dsize_q = 0;
        const char *dfree_command;
        static bool dfree_broken = false;
        const char *path = fname->base_name;

        (*dfree) = (*dsize) = 0;
        (*bsize) = 512;

        /*
         * If external disk calculation specified, use it.
         */

        dfree_command = lp_dfree_command(talloc_tos(), SNUM(conn));
        if (dfree_command && *dfree_command) {
                const char *p;
                char **lines = NULL;
                char *syscmd = NULL;

                syscmd = talloc_asprintf(talloc_tos(),
                                "%s %s",
                                dfree_command,
                                path);

                if (!syscmd) {
                        return (uint64_t)-1;
                }

                DEBUG (3, ("disk_free: Running command '%s'\n", syscmd));

                lines = file_lines_pload(syscmd, NULL);
                if (lines != NULL) {
                        char *line = lines[0];

                        DEBUG (3, ("Read input from dfree, \"%s\"\n", line));

                        *dsize = STR_TO_SMB_BIG_UINT(line, &p);
                        while (p && *p && isspace(*p))
                                p++;
                        if (p && *p)
                                *dfree = STR_TO_SMB_BIG_UINT(p, &p);
                        while (p && *p && isspace(*p))
                                p++;
                        if (p && *p)
                                *bsize = STR_TO_SMB_BIG_UINT(p, NULL);
                        else
                                *bsize = 1024;
                        TALLOC_FREE(lines);
                        DEBUG (3, ("Parsed output of dfree, dsize=%u, dfree=%u, bsize=%u\n",
                                (unsigned int)*dsize, (unsigned int)*dfree, (unsigned int)*bsize));

                        if (!*dsize)
                                *dsize = 2048;
                        if (!*dfree)
                                *dfree = 1024;

                        goto dfree_done;
                }
                DEBUG (0, ("disk_free: file_lines_load() failed for "
                           "command '%s'. Error was : %s\n",
                           syscmd, strerror(errno) ));
        }

        if (SMB_VFS_DISK_FREE(conn, path, bsize, dfree, dsize) ==
            (uint64_t)-1) {
                DBG_ERR("VFS disk_free failed. Error was : %s\n",
                        strerror(errno));
                return (uint64_t)-1;
        }

        if (disk_quotas(conn, fname, &bsize_q, &dfree_q, &dsize_q)) {
                uint64_t min_bsize = MIN(*bsize, bsize_q);

                (*dfree) = (*dfree) * (*bsize) / min_bsize;
                (*dsize) = (*dsize) * (*bsize) / min_bsize;
                dfree_q = dfree_q * bsize_q / min_bsize;
                dsize_q = dsize_q * bsize_q / min_bsize;

                (*bsize) = min_bsize;
                (*dfree) = MIN(*dfree,dfree_q);
                (*dsize) = MIN(*dsize,dsize_q);
        }

        /* FIXME : Any reason for this assumption ? */
        if (*bsize < 256) {
                DEBUG(5,("disk_free:Warning: bsize == %d < 256 . Changing to assumed correct bsize = 512\n",(int)*bsize));
                *bsize = 512;
        }

        if ((*dsize)<1) {
                if (!dfree_broken) {
                        DEBUG(0,("WARNING: dfree is broken on this system\n"));
                        dfree_broken=true;
                }
                *dsize = 20*1024*1024/(*bsize);
                *dfree = MAX(1,*dfree);
        }

dfree_done:
        disk_norm(bsize, dfree, dsize);

        if ((*bsize) < 1024) {
                dfree_retval = (*dfree)/(1024/(*bsize));
        } else {
                dfree_retval = ((*bsize)/1024)*(*dfree);
        }

        return(dfree_retval);
}

/****************************************************************************
 Potentially returned cached dfree info.
****************************************************************************/

uint64_t get_dfree_info(connection_struct *conn, struct smb_filename *fname,
                        uint64_t *bsize, uint64_t *dfree, uint64_t *dsize)
{
        int dfree_cache_time = lp_dfree_cache_time(SNUM(conn));
        struct dfree_cached_info *dfc = conn->dfree_info;
        uint64_t dfree_ret;

        if (!dfree_cache_time) {
                return sys_disk_free(conn, fname, bsize, dfree, dsize);
        }

        if (dfc && (conn->lastused - dfc->last_dfree_time < dfree_cache_time)) {
                /* Return cached info. */
                *bsize = dfc->bsize;
                *dfree = dfc->dfree;
                *dsize = dfc->dsize;
                return dfc->dfree_ret;
        }

        dfree_ret = sys_disk_free(conn, fname, bsize, dfree, dsize);

        if (dfree_ret == (uint64_t)-1) {
                /* Don't cache bad data. */
                return dfree_ret;
        }

        /* No cached info or time to refresh. */
        if (!dfc) {
                dfc = talloc(conn, struct dfree_cached_info);
                if (!dfc) {
                        return dfree_ret;
                }
                conn->dfree_info = dfc;
        }

        dfc->bsize = *bsize;
        dfc->dfree = *dfree;
        dfc->dsize = *dsize;
        dfc->dfree_ret = dfree_ret;
        dfc->last_dfree_time = conn->lastused;

        return dfree_ret;
}