source: vendor/3.6.23/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(bool small_query, uint64_t *bsize,uint64_t *dfree,uint64_t *dsize)
{
        /* check if the disk is beyond the max disk size */
        uint64_t maxdisksize = lp_maxdisksize();
        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 */
        }  

        if(small_query) {       
                while (*dfree > WORDMAX || *dsize > WORDMAX || *bsize < 512) {
                        *dfree /= 2;
                        *dsize /= 2;
                        *bsize *= 2;
                        /*
                         * Force max to fit in 16 bit fields.
                         */
                        if (*bsize > (WORDMAX*512)) {
                                *bsize = (WORDMAX*512);
                                if (*dsize > WORDMAX)
                                        *dsize = WORDMAX;
                                if (*dfree >  WORDMAX)
                                        *dfree = WORDMAX;
                                break;
                        }
                }
        }
}



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

uint64_t sys_disk_free(connection_struct *conn, const char *path, bool small_query, 
                              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;

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

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

        dfree_command = lp_dfree_command(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) {
                        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;
                } else {
                        DEBUG (0, ("disk_free: sys_popen() failed for command %s. Error was : %s\n",
                                syscmd, strerror(errno) ));
                        if (sys_fsusage(path, dfree, dsize) != 0) {
                                DEBUG (0, ("disk_free: sys_fsusage() failed. Error was : %s\n",
                                        strerror(errno) ));
                                return (uint64_t)-1;
                        }
                }
        } else {
                if (sys_fsusage(path, dfree, dsize) != 0) {
                        DEBUG (0, ("disk_free: sys_fsusage() failed. Error was : %s\n",
                                strerror(errno) ));
                        return (uint64_t)-1;
                }
        }

        if (disk_quotas(path, &bsize_q, &dfree_q, &dsize_q)) {
                (*bsize) = bsize_q;
                (*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);
        }

        disk_norm(small_query,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,
                        const char *path,
                        bool small_query,
                        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 SMB_VFS_DISK_FREE(conn,path,small_query,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 = SMB_VFS_DISK_FREE(conn,path,small_query,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_P(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;
}