est_ops.c

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/************************************************************************
 * Copyright (C) 2005-2009 Philipp Marek.
 *
 * This program is free software;  you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 ************************************************************************/

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>


#include "global.h"
#include "status.h"
#include "cache.h"
#include "actions.h"
#include "est_ops.h"
#include "ignore.h"
#include "direnum.h"
#include "warnings.h"
#include "helper.h"
#include "checksum.h"
#include "url.h"

struct free_estat
{
    struct free_estat *next;
    int count; 
};



const char ops__dir_info_format_p[]="%07llo %8x %8x %x %s %s "
"%lld %ld %u %lx %lld %lld %u "
"%u %u %s";
#define WAA_MAX_DIR_INFO_CHARS (11+1+8+1+8+1+8+1+APR_MD5_DIGESTSIZE*2+1 \
        +18+1+9+1+9+1+16+1+18+1+18+1+9+1+ \
        9+1+9+1+NAME_MAX+1+1)


const char link_spec[]="link ",
            cdev_spec[]="cdev",
            bdev_spec[]="bdev";

static struct free_estat *free_list = NULL;



int ops__string_to_dev(struct estat *sts, char *data, char **info)
{
    int maj, min;
    int ft, mode, len;
    char delimiter;
    int status;


    status=0;
    if (0 == strncmp(data, link_spec, strlen(link_spec)))
    {
        mode=S_IFLNK;
        if (info)
            *info=data+5;
    }
    else
    {
        if (0 == strncmp(data, cdev_spec, strlen(cdev_spec)))
        {
            data+=strlen(cdev_spec);
            mode=S_IFCHR;
        }
        else if (0 == strncmp(data, bdev_spec, strlen(bdev_spec)))
        {
            data+=strlen(bdev_spec);
            mode=S_IFBLK;
        }
        else mode=0;


        ft=sscanf(data, "%c0x%X:0x%X%n", &delimiter, &maj, &min, &len);

        STOPIF_CODE_ERR(mode == 0 ||
                ft != 3 || 
                (delimiter != ':' && delimiter != ' '),
                EINVAL,
                "'%s' is not parseable as a special description", data);

        if (info) *info=data+len;

#ifdef DEVICE_NODES_DISABLED
        DEVICE_NODES_DISABLED();
#else
        sts->st.rdev=MKDEV(maj, min);
#endif
    }

    sts->st.mode= (sts->st.mode & ~S_IFMT) | mode;
    sts->local_mode_packed = MODE_T_to_PACKED(mode);

ex:
    return status;
}


int ops__link_to_string(struct estat *sts, char *filename,
        char **erg)
{
    static struct cache_t *cache=NULL;
    char *cp;
    int l, status, hlen;


    STOPIF( cch__new_cache(&cache, 4), NULL);


    status=0;
    BUG_ON(!S_ISLNK(sts->st.mode));

    if (!filename)
        STOPIF( ops__build_path(&filename, sts), NULL); 

    hlen=strlen(link_spec);
    l=sts->st.size + hlen + 1 + 8;
    STOPIF( cch__add(cache, 0, NULL, l, &cp), NULL);

    strcpy(cp, link_spec);
    STOPIF_CODE_ERR( readlink(filename, cp+hlen, sts->st.size) == -1,
            errno, "can't read link %s", filename);

    cp[hlen+sts->st.size]=0;
    *erg=cp;

ex:
    return status;
}


char *ops___dev_to_string(struct estat *sts, char delimiter)
{
    static char buffer[64];

    /* I'm not fully sure about that. */
    BUG_ON(!(sts->remote_status & FS_NEW) && 
            !(S_ISBLK(sts->st.mode) || S_ISCHR(sts->st.mode)),
            "%s: mode is 0%o", sts->name, sts->st.mode);

#ifdef DEVICE_NODES_DISABLED
    DEVICE_NODES_DISABLED();
#else
    sprintf(buffer, "%s%c0x%x:0x%x",
            S_ISBLK(sts->st.mode) ? bdev_spec : cdev_spec,
            delimiter,
            (int)MAJOR(sts->st.rdev),
            (int)MINOR(sts->st.rdev));
#endif

    return buffer;
}


char *ops__dev_to_waa_string(struct estat *sts)
{
    return ops___dev_to_string(sts, ':');
}


char *ops__dev_to_filedata(struct estat *sts)
{
    return ops___dev_to_string(sts, ' ');
}


int ops__stat_to_action(struct estat *sts, struct sstat_t *new)
{
    struct sstat_t *old;
    int ft_old, ft_new;
    int file_status;


    old=&(sts->st);

    /* The exact comparison here would be
     *   old->_mtime != new->_mtime ||
     *   old->_ctime != new->_ctime ? FS_META_MTIME : 0;
     * but that doesn't work, as most filesystems don't have 
     * nanoseconds stored. Furthermore we get only usec in the repository
     * (due to svn_time_to_string), so the nsec make no sense here.
     * We compare only the "coarse", but common, granularity of seconds.
     * VFAT can store only even seconds!
     *
     * The problem gets a bit more complicated as the linux kernel keeps
     * nsec in the dentry (cached inode), but as soon as the inode has to be
     * read from disk it has possibly only seconds!
     *
     * There's a long thread on dev@subversion.tigris.org about the
     * granularity of timestamps - auto detecting vs. setting, etc. */
    file_status = 
        old->mtim.tv_sec != new->mtim.tv_sec ? FS_META_MTIME : 0;
    /* We don't show a changed ctime as "t" any more. On commit nothing 
     * would change in the repository, and it looks a bit silly.
     * A changed ctime is now only used as an indicator for changes. */

    if (old->uid != new->uid)
        file_status |= FS_META_OWNER;
    if (old->gid != new->gid)
        file_status |= FS_META_GROUP;

    if (old->mode != new->mode)
        file_status |= FS_META_UMODE;

    /* both of same type ? */
    ft_old = old->mode & S_IFMT;
    ft_new = new->mode & S_IFMT;

    if (ft_old != ft_new)
    {
        file_status |= FS_REPLACED;
        goto ex;
    }

    /* same type - compare */
    BUG_ON(sts->to_be_ignored);
    switch (ft_new)
    {
        case S_IFBLK:
        case S_IFCHR:
            DEBUGP("old=%llu new=%llu", (t_ull)old->rdev, (t_ull)new->rdev);
            file_status |= 
                (old->rdev == new->rdev) 
                ? FS_NO_CHANGE : FS_REPLACED;
            break;

        case S_IFLNK:
        case S_IFREG:
            if (old->size != new->size)
                file_status |= FS_CHANGED;
            else
                /* The changed flag can be set or cleared by cs__compare_file().
                 * We don't set it until we *know* the entry has changed. */
                /* If the entry is copied, the ctime *must* be different (unless 
                 * it's a hardlink); here we assume that it's not changed, if the 
                 * mtime is the same. */
                if ((file_status & FS_META_MTIME) ||
                        (old->ctim.tv_sec != new->ctim.tv_sec && 
                         !(sts->flags & RF___IS_COPY)) )
                    file_status |= FS_LIKELY;
            break;

        case S_IFDIR:
            /* This entry *could* be changed.
             * But as the changed flag is set if a child entry is missing
             * or if new entries are found, but never cleared, we don't set 
             * it here. */
            if ( (file_status & FS_META_MTIME) ||
                    old->ctim.tv_sec != new->ctim.tv_sec )
                file_status |= FS_LIKELY;
            break;

        default:
            BUG_ON(1);
            //      case FT_IGNORE:
            file_status=FS_NO_CHANGE;
    }

ex:
    DEBUGP("change: types 0%o vs 0%o; 0x%x=%s", 
            ft_old, ft_new,
            file_status, 
            st__status_string_fromint(file_status));
    return file_status;
}


int ops__load_1entry(char **mem_pos, struct estat *sts, char **filename,
        ino_t *parent_i)
{
    char *buffer, *before;
    int status;
    ino_t parent_inode;
       unsigned internal_number, e_t;



    status=0;
    buffer=*mem_pos;

    /* Now parse. Use temporary variables of defined size for some inputs. */
    /* The parsing is in a block, followed by the checks, so that the icache 
     * is happy. */
    /* Hexadecimal allows more characters than octal, so we have to check 
     * whether something was done here.
     * Below we can try some conversions (for the same base) one after 
     * another, and only check the last - if a bad character is in the 
     * string, all of the last calls will fail, so we only need to check the 
     * last conversion in each per-base block.
     * We have to skip the initial whitespace; if there's eg " X" in the 
     * string, the space would be skipped, and the pointers different. */
    before=hlp__skip_ws(buffer);
    sts->st.mode = strtoul(before, &buffer, 8);
    sts->old_rev_mode_packed = 
        sts->new_rev_mode_packed = 
        sts->local_mode_packed = MODE_T_to_PACKED(sts->st.mode);
    if (before == buffer) goto inval;
    /* And we know that we write a space; without this a later test would 
     * fail, and give some misleading error. */
    if (*(buffer++) != ' ') goto inval;


    /* Base 16. */
    sts->st.ctim.tv_sec= strtoul(buffer, &buffer, 16);
    sts->st.mtim.tv_sec= strtoul(buffer, &buffer, 16);
    before=hlp__skip_ws(buffer);
    sts->flags= strtoul(before, &buffer, 16);
    if (before == buffer) goto inval;
    if (*(buffer++) != ' ') goto inval;


    /* Devices have major:minor stored */
    buffer=hlp__skip_ws(buffer);
    if (S_ISBLK(sts->st.mode) || S_ISCHR(sts->st.mode))
        STOPIF( ops__string_to_dev(sts, buffer, &buffer), NULL);
    else
        buffer=hlp__get_word(buffer, NULL);

    /* All entries but directories have MD5 */
    buffer=hlp__skip_ws(buffer);
    if (!S_ISDIR(sts->st.mode))
        STOPIF( cs__char2md5( buffer, &buffer, sts->md5),
                "Parsing the md5 failed");
    else
        buffer=hlp__get_word(buffer, NULL);


    /* Base 10. */
    sts->st.size = strtoul(buffer, &buffer, 10); 
    sts->old_rev = sts->repos_rev = strtoul(buffer, &buffer, 10); 
    internal_number = strtoul(buffer, &buffer, 10); 
    sts->st.dev = strtoul(buffer, &buffer, 16); 
    sts->st.ino = strtoul(buffer, &buffer, 10); 
    parent_inode= strtoul(buffer, &buffer, 10); 
       e_t = strtoul(buffer, &buffer, 10);
    sts->st.uid = strtoul(buffer, &buffer, 10); 
    before=hlp__skip_ws(buffer);
    sts->st.gid = strtoul(before, &buffer, 10); 
    if (before == buffer) goto inval;


       /* We need to parse, but would overwrite the shared md5 member. */
       if (S_ISDIR(sts->st.mode))
               sts->entry_count = e_t;
       /* Only a directory may have children. We cannot test sts->entry_count,
        * as this is already overwritten by the MD5. */
       BUG_ON(e_t && !S_ISDIR(sts->st.mode));


    /* Skip over exactly one space - else we'd loose information about 
     * filenames starting with whitespaces. */
    if (*buffer != ' ') goto inval;
    *filename=buffer+1;


    /* Only the root entry has parent_inode==0; the others start counting 
     * with 1. */
    if (parent_inode)
    {
        /* There may be entries without an URL associated - eg. entries which
         * were just added, but not committed. */
        if (internal_number)
            STOPIF( url__find_by_intnum(internal_number, &(sts->url)), NULL);
    }
    else
    {
        /* The root entry gets the highest priority url.
         * There may be no URLs defined! */
        sts->url= urllist_count ? 
            urllist[urllist_count-1] : 
            NULL;
    }

    if (parent_i) *parent_i=parent_inode;

    /* Advance memory pointer past end of filename.
     * Skip \0 and \n.
     * If we didn't skip the \n, the next sscanf() should work, too;
     * but the caller would have a hard time figuring if we're already
     * finished. */
    *mem_pos = *filename + strlen(*filename) + 1;
    if (**mem_pos == '\n') (*mem_pos)++;

ex:
    return status;
    /* Out of line */

inval:
    STOPIF( EINVAL, "Error parsing entry line \"%s\";\n"
            "your entry list is corrupt, ask the users mailing list, please.", 
            *mem_pos);
    /* gcc warns about reaching the end of a non-void function - which can't 
     * really happen here, but to humor the compiler ... */
    goto ex;
}


int ops___entries_to_write(struct estat *dir)
{
    struct estat **list;
    int count;

    count=0;
    if (!dir->entry_count) return 0;
    list=dir->by_inode;
    while (*list)
    {
        if (ops__should_entry_be_written_in_list(*list)) 
            count++;
        list++;
    }

    return count;
}


int ops__save_1entry(struct estat *sts,
        ino_t parent_ino,
        int filehandle)
{
    int len;
    static char buffer[WAA_MAX_DIR_INFO_CHARS+2] = 
    { 
        // overrun detection for debugging
        [sizeof(buffer)-1]=0xff,
        [sizeof(buffer)-2]=0x0,
    };
    int is_dir, is_dev, status, is_spec;
    int intnum;


#if 0
    if (sts->parent)
    {
        /* For entries other than the root node:
         * If the entry was not added or copied, it has to have an URL.
         *
         * But we cannot test for that, as _build_list does exactly that - and 
         * is needed by the tests. */
        BUG_ON(!sts->url && 
                !(sts->flags & (RF_COPY_SUB | RF_COPY_BASE | RF_ADD)));
    }
#endif

    is_dir = S_ISDIR(sts->st.mode);
    is_dev = S_ISBLK(sts->st.mode) || S_ISCHR(sts->st.mode);
    is_spec = S_ISBLK(sts->st.mode) || S_ISCHR(sts->st.mode) ||
        S_ISLNK(sts->st.mode);


    if (sts->match_pattern)
        STOPIF( ops__apply_group(sts, NULL, NULL), NULL);


    if (sts->url)
        intnum=sts->url->internal_number;
    else
    {
        /* A non-root entry has no url. May happen with _build_list, when
         * there are no urls. */
        if (sts->parent)
            DEBUGP("Non-root entry %s has no URL", sts->name);
        intnum=0;
    }

    len=sprintf(buffer, ops__dir_info_format_p,
            (t_ull)sts->st.mode,
            (int)sts->st.ctim.tv_sec,
            (int)sts->st.mtim.tv_sec,
            sts->flags & RF___SAVE_MASK,
            ( is_dev ? ops__dev_to_waa_string(sts) : "nd" ),
            ( is_dir ? "x" : cs__md5tohex_buffered(sts->md5) ),
            (t_ull)sts->st.size,
            sts->repos_rev == SET_REVNUM ? sts->url->current_rev : sts->repos_rev,
            intnum,
            (t_ul)sts->st.dev,
            (t_ull)sts->st.ino,
            (t_ull)parent_ino,
            /* We have to make sure that the entry count in the parent is 
             * correct. */
            is_dir ? ops___entries_to_write(sts) : 0,
            sts->st.uid,
            sts->st.gid,
            sts->name
            );
    BUG_ON(len > sizeof(buffer)-2);
    len++; // include \0
    buffer[len++]='\n';

    // redundant (?) check
    BUG_ON(buffer[sizeof(buffer)-1]!=0xff || 
            buffer[sizeof(buffer)-2]!=0x0);

    is_dir=write(filehandle, buffer, len);
    STOPIF_CODE_ERR(is_dir != len, errno, 
            "write entry");

    status=0;

ex:
    return status;
}


char *ops__get_filename(char *path)
{
    char *cp;

    cp=strrchr(path, PATH_SEPARATOR);
    return cp ? cp+1 : path;
}


static inline const char *ops___split_fnpart(const char *path)
{
    char *cp;

    cp=strchr(path, PATH_SEPARATOR);
    if (!cp) return NULL;

    /* Overwrite multiple path separators */
    while (*cp == PATH_SEPARATOR) *(cp++)=0;

    /* If the path looks like "name////", there's no next_part, too. */
    if (!*cp) return NULL;

    return cp;
}


int ops__build_path2(char *path, int max, struct estat *sts)
{
    int l,i;


    /* The path lenghts have just been fixed by ops__calc_path_len(), so we 
     * can rely on that (minus the PATH_SEPARATOR).
     * If there's no parent, we're at ".". */
    l=sts->parent ? sts->path_len - sts->parent->path_len - 1 : 1;
    if (l+1 > max) return 0;

    if (sts->parent)
    {
        i=ops__build_path2(path, max - (l+1), sts->parent);

        /* not enough space ? */
        if (!i) return 0; 
    }
    else
    {
        i=0;
    }

    memcpy(path+i, sts->name, l);
    path[i+l+0]=PATH_SEPARATOR;
    path[i+l+1]=0;

    return i+l+1;
}


int ops__calc_path_len(struct estat *sts)
{
    int plen;

    if (sts->parent)
    {
        if (!sts->parent->path_len) 
            ops__calc_path_len(sts->parent);
        /* Include the path separator. */
        plen=sts->parent->path_len+1;
    }
    else
        plen=0;

    sts->path_len = plen + strlen(sts->name);
    return sts->path_len;
}


int ops__build_path(char **value, struct estat *sts)
{
    static struct cache_t *cache=NULL;
    int status, i;
    unsigned needed_space;
    char *data;

    /* Please note that in struct \ref estat there's a bitfield, and its member 
     * \ref cache_index must take the full range plus an additional "out of 
     * range" value! */
    STOPIF( cch__new_cache(&cache, 48), NULL);

    /* Look if it's cached. */
    if (sts->cache_index>0 &&
            sts->cache_index<=cache->max && 
            cache->entries[sts->cache_index-1]->id == (cache_value_t)sts &&
            cache->entries[sts->cache_index-1]->data[0])
    {
        /* the found entry has index i; we'd like that to be the LRU. */
        i=sts->cache_index-1;
        DEBUGP("%p found in cache index %d; lru %d",
                sts, i, cache->lru);
        cch__set_active(cache, i);
        goto ex;
    }

    if (!sts->path_len)
        ops__calc_path_len(sts);

    needed_space=sts->path_len+1;

    STOPIF( cch__add(cache, (cache_value_t)sts, NULL, 
                needed_space, &data), NULL);

    /* Now we have an index, and enough space. */
    status=ops__build_path2(data, needed_space, sts);
    if (status == 0)
    {
        /* Something happened with our path length counting -
         * it's really a bug. */
        BUG("path len counting went wrong");
    }

    data[status-1]=0;
    sts->cache_index=cache->lru+1;
    status=0;

ex:
    //  DEBUGP("status=%d; path=%s", status, cache->entries[cache->lru]->data);
    if (!status) *value=cache->entries[cache->lru]->data;
    return status;
}


int ops__new_entries(struct estat *dir,
        int count,
        struct estat **new_entries)
{
    int status;


    status=0;
    /* By name is no longer valid. */
    IF_FREE(dir->by_name);
    /* Now insert the newly found entries in the dir list. */
    STOPIF( hlp__realloc( &dir->by_inode, 
                (dir->entry_count+count+1) * sizeof(dir->by_inode[0])), NULL);

    memcpy(dir->by_inode+dir->entry_count,
            new_entries, count*sizeof(dir->by_inode[0]));
    dir->entry_count += count;
    dir->by_inode[dir->entry_count]=NULL;

    /* Re-sort the index next time it's needed. */
    dir->to_be_sorted=1;

ex:
    return status;
}


int ops__find_entry_byname(struct estat *dir, char *name, 
        struct estat **sts,
        int ignored_too)
{
    int status;
    struct estat **sts_p;
    char *filename;


    status=0;
    BUG_ON(!S_ISDIR(dir->st.mode));

    if (!dir->by_name)
        STOPIF(dir__sortbyname(dir), NULL);

    /* Strip the path, leave the file name */
    filename=ops__get_filename(name);

    /* find entry, binary search. */
    sts_p=bsearch(filename, dir->by_name, dir->entry_count, 
            sizeof(dir->by_name[0]), 
            (comparison_fn_t)dir___f_sort_by_nameCS);

    if (sts_p)
        DEBUGP("found %s on %p; ignored: 0x%x", name, sts_p,
                (*sts_p)->to_be_ignored);

    /* don't return removed entries, if they're not wanted */
    *sts=sts_p && (!(*sts_p)->to_be_ignored || ignored_too) ?
        *sts_p : NULL;

    if (!*sts)
        DEBUGP("Searching for %s (%s) found no entry (ignored_too=%d)",
                filename, name, ignored_too);

ex:
    return status;
}


#if 0
// Currently unused
int ops__find_entry_byinode(struct estat *dir, 
        dev_t dev, 
        ino_t inode, 
        struct estat **sts)
{
    int status;
    struct estat **sts_p;
    struct estat sts_cmp;


    status=0;
    BUG_ON(!S_ISDIR(dir->st.mode));

    if (!dir->by_inode) 
        STOPIF(dir__sortbyinode(dir), NULL);

    sts_cmp.st.dev=dev;
    sts_cmp.st.ino=inode;

    /* find entry, binary search. */
    sts_p=bsearch(&sts_cmp, dir->by_inode, dir->entry_count, 
            sizeof(dir->by_inode[0]), 
            (comparison_fn_t)dir___f_sort_by_inode);

    *sts=sts_p && ((*sts_p)->entry_status != FT_IGNORE) ?
        *sts_p : NULL;

ex:
    return status;
}
#endif


static inline void ops___move_array(struct estat **array, int index, int len)
{
    /* From A B C D E F i H J K l  NULL
     * to   A B C D E F H J K l  NULL */
    memmove( array+index, array+index+1,
            /* +1 below is for the NULL */
            (len-index-1+1) * sizeof(*array) );
}


int ops__allocate(int needed, 
        struct estat **where, int *count)
{
    struct free_estat *free_p;
    int status, remain;
    int returned;


    status=0;
    BUG_ON(needed <=0, "not even a single block needed?");

    DEBUGP("need %d blocks, freelist=%p", needed, free_list);
    if (free_list)
    {
        free_p=free_list;
        VALGRIND_MAKE_MEM_DEFINED(free_p, sizeof(*free_p));

        if (free_p->count <= needed)
        {
            /* Whole free block is used up */
            free_list=free_p->next;

            returned=free_p->count;
            *where=(struct estat*)free_p;
        }
        else
        {
            /* Only part of this block is needed.
             * We return the "higher" part in memory, so that the free list
             * is not changed.
             *
             * Needed: 3
             * Free block:  [0 1 2 3 4 5] size=6
             * Returned:           ^ 
             *    size=3 after*/
            returned=needed;

            remain=free_p->count-needed;
            *where=((struct estat*)free_p) + remain;
            free_p->count=remain;
            DEBUGP("splitting block; %d remain", remain);
        }

        VALGRIND_MAKE_MEM_DEFINED(*where, sizeof(**where)*returned);
        /* Clear the memory. Not needed for calloc(). */
        memset(*where, 0, sizeof(**where) * returned);
    }
    else
    {
        DEBUGP("no free list, allocating");
        /* No more free entries in free list. Allocate. */
        returned=needed;
        /* Allocate at least a certain block size. */
        if (needed < 8192/sizeof(**where)) 
            needed=8192/sizeof(**where);
        STOPIF( hlp__calloc( where, needed, sizeof(**where)), NULL);

        if (needed > returned)
        {
            free_list=(struct free_estat*)(*where+returned);
            free_list->next=NULL;
            free_list->count=needed-returned;
        }
    }

    DEBUGP("giving %d blocks at %p", returned, *where);
    BUG_ON(!returned, "Not even a single block returned!!");
    if (count)
        *count=returned;

    /* The memory is cleared; cache_index == 0 means uninitialized, which is 
     * exactly what we want. */

    VALGRIND_MAKE_MEM_DEFINED(*where, sizeof(**where) * returned);

ex:
    return status;
}


int ops__free_entry(struct estat **sts_p)
{
    int i, status;
    struct estat *sts=*sts_p;
    struct free_estat *free_p, *free_p2;
    struct free_estat **prev;
    struct free_estat *block;


    status=0;
    if (sts->old)
        STOPIF( ops__free_entry(& sts->old), NULL);
    if (S_ISDIR(sts->st.mode))
    {
        BUG_ON(sts->entry_count && !sts->by_inode);

        for(i=0; i<sts->entry_count; i++)
            STOPIF( ops__free_entry(sts->by_inode+i), NULL);

        IF_FREE(sts->by_inode);
        IF_FREE(sts->by_name);
        IF_FREE(sts->strings);
        sts->st.mode=0;
    }

    /* Clearing the memory here serves no real purpose;
     * the free list written here overwrites parts.
     * So we clear on allocate. */

    /* TODO: insert into free list (pointer, element count) with merging. 
     * That requires finding a free block just below or just above
     * the current sts, and check if the current and the free can be merged.
     * Currently the list is just prepended.
     *
     * TODO: The list should be sorted in some way.
     * Possibly by address and size in two trees, to quickly find
     * the largest free block or the nearest block.
     */
    /* The freed block stores the list data to other blocks. */
    DEBUGP("freeing block %p", *sts_p);

    block=(struct free_estat*)*sts_p;
    /* Can we merge? */
    free_p=free_list;
    prev=&free_list;
    while (free_p)
    {
        VALGRIND_MAKE_MEM_DEFINED(free_p, sizeof(*free_p));
        if ((char*)block + sizeof(struct estat) == (char*)free_p)
        {
            /* Copy data */
            block->count = free_p->count+1;
            block->next = free_p->next;
            if (prev != &free_list)
                VALGRIND_MAKE_MEM_DEFINED(prev, sizeof(*prev));
            *prev = block;
            if (prev != &free_list)
                VALGRIND_MAKE_MEM_NOACCESS(prev, sizeof(*prev));
            break;
        }

        if ((char*)block == (char*)free_p+sizeof(struct estat)*free_p->count)
        {
            free_p->count++;
            break;
        }

        prev=&free_p->next;
        free_p2=free_p;

        free_p=*prev;

        VALGRIND_MAKE_MEM_NOACCESS(free_p2, sizeof(*free_p2));
    }


    if (free_p)
    {
        DEBUGP("merged to %p; now size %d", block, free_p->count);
        VALGRIND_MAKE_MEM_NOACCESS(free_p, sizeof(*free_p));
    }
    else
    {
        block->next=free_list;
        block->count=1;
        free_list=block;
        DEBUGP("new entry in free list");
    }

    VALGRIND_MAKE_MEM_NOACCESS( block, sizeof(struct estat));

    *sts_p=NULL;

ex:
    return status;
}


int ops__delete_entry(struct estat *dir, 
        struct estat *sts, 
        int index_byinode, 
        int index_byname)
{
    int i;
    int status;

    BUG_ON( (sts ? 1 : 0) +
            (index_byinode >=0 ? 1 : 0) +
            (index_byname >=0 ? 1 : 0) 
            != 1,
            "must have exactly 1 definition!!!");


    BUG_ON(!S_ISDIR(dir->st.mode), "can remove only from directory");

    if (!sts)
    {
        if (index_byinode != UNKNOWN_INDEX)
        {
            BUG_ON(index_byinode > dir->entry_count, "i > c");
            sts=dir->by_inode[index_byinode];
        }
        else
        {
            BUG_ON(index_byname > dir->entry_count, "i > c");
            sts=dir->by_name[index_byname];
        }
    }


    i=0;
    if (dir->by_inode)
    {
        if (index_byinode == UNKNOWN_INDEX)
        {
            /* Maybe use ops__find_entry_byinode ? Would be faster for large 
             * arrays - but the bsearch wouldn't return an index, only a pointer.  
             * */
            for(index_byinode=dir->entry_count-1; 
                    index_byinode>=0; 
                    index_byinode--)
                if (dir->by_inode[index_byinode] == sts) break;

            BUG_ON(index_byinode == UNKNOWN_INDEX);
        }

        ops___move_array(dir->by_inode, index_byinode,
                dir->entry_count);
        i=1;
    }

    if (dir->by_name)
    {
        if (index_byname == UNKNOWN_INDEX)
        {
            /* Maybe use ops__find_entry_byname? Would do a binary search, but 
             * using string compares. */
            for(index_byname=dir->entry_count-1; 
                    index_byname>=0; 
                    index_byname--)
                if (dir->by_name[index_byname] == sts) break;

            BUG_ON(index_byname == UNKNOWN_INDEX);
        }

        ops___move_array(dir->by_name, index_byname,
                dir->entry_count);
        i=1;
    }

    STOPIF( ops__free_entry(&sts), NULL);

ex:
    DEBUGP("entry count was %d; flag to remove is %d",
            dir->entry_count, i);
    if (i)
        dir->entry_count--;
    return i ? 0 : ENOENT;
}


int ops__free_marked(struct estat *dir, int fast_mode)
{
    struct estat **src, **dst;
    int i, new_count;
    int status;


    BUG_ON(!S_ISDIR(dir->st.mode));
    status=0;

    IF_FREE(dir->by_name);

    src=dst=dir->by_inode;
    new_count=0;
    for(i=0; i<dir->entry_count; i++)
    {
        if (!(*src)->to_be_ignored)
        {
            *dst=*src;
            dst++;
            new_count++;
        }
        else
        {
            if (!fast_mode)
                STOPIF( ops__free_entry(src), NULL);
        }

        src++;
    }

    if (new_count != dir->entry_count)
    {
        if (!fast_mode)
        {
            /* resize by_inode - should never give NULL. */
            STOPIF( hlp__realloc( &dir->by_inode, 
                        sizeof(*(dir->by_inode)) * (new_count+1) ), NULL);
        }

        dir->by_inode[new_count]=NULL;
        dir->entry_count=new_count;
    }

ex:
    return status;
}


int ops__traverse(struct estat *current, char *fullpath, 
        int flags,
        int sts_flags,
        struct estat **ret)
{
    int status;
    char *next_part;
    struct estat *sts;
    int quit;
    char *copy, *path;


    status=0;
    STOPIF( hlp__strdup( &copy, fullpath), NULL);
    path=copy;

    quit=0;
    while (path)
    {
        next_part=(char*)ops___split_fnpart(path);

        BUG_ON(!path[0]);

        /* Check special cases. */
        if (path[0] == '.' && 
                path[1] == '\0')
        {
            /* This happens for the start of a wc-relative path: ./dir/file */
            path=next_part;
            continue;
        }

        if (path[0] == '.' && 
                path[1] == '.' &&
                path[2] == '\0')
        {
            /* This shouldn't happen; the paths being worked on here should be 
             * normalized.  */
            BUG("Path '%s' includes '..'!", fullpath);
        }


        /* Look in this directory for the wanted entry.
         * If there's an ignored entry, we'll take that, too. */
        STOPIF( ops__find_entry_byname(current, path, &sts, 1), NULL);

        if (!sts)
        {
            /* If we may not create it, print the optional warning, and possibly  
             * return an error.
             * Print no error message, as the caller may want to catch this. */
            if (!(flags & OPS__CREATE))
            {
                if (flags & OPS__FAIL_NOT_LIST)
                    STOPIF_CODE_ERR( 1, ENOENT,
                            "!The entry '%s' was not found.", fullpath);

                status=ENOENT;
                goto ex;
            }

            /* None found, make a new. */
            STOPIF( ops__allocate(1, &sts, NULL), NULL);
            STOPIF( hlp__strdup( &sts->name, path), NULL);

            if (flags & OPS__ON_UPD_LIST)
                STOPIF( waa__insert_entry_block(sts, 1), NULL);

            /* Fake a directory node. */
            sts->st.mode=S_IFDIR | 0700;
            sts->st.size=0;
            sts->entry_count=0;
            sts->parent=current;
            /* Add that directory with the next commit. */
            sts->flags=sts_flags | RF_ISNEW;


            STOPIF( ops__new_entries(current, 1, &sts), NULL);
        }

        current=sts;

        path=next_part;
    }

    *ret=current;

ex: 
    IF_FREE(copy);
    return status;
}


int ops__update_single_entry(struct estat *sts, struct sstat_t *output)
{
    int status;
    struct sstat_t st;
    int i;
    char *fullpath;


    STOPIF( ops__build_path(&fullpath, sts), NULL);

    /* If we see that the parent has been removed, there's no need
     * to check this entry - the path will surely be invalid. */
    if (sts->parent)
        if (sts->parent->entry_status & FS_REMOVED)
        {
            goto removed;
        }

    /* Check for current status */
    status=hlp__lstat(fullpath, &st);

    if (status)
    {
        DEBUGP("lstat whines %d", status);

        /* only valid error is ENOENT - then this entry has been removed */
        /* If we did STOPIF_CODE_ERR(status != ENOENT ...), then status
         * would be overwritten with the value of the comparison. */
        if (abs(status) != ENOENT) 
            STOPIF(status, "cannot lstat(%s)", fullpath);

removed:
        /* Re-set the values, if needed */
        if (st.mode)
            memset(&st, 0, sizeof(st));

        sts->entry_status=FS_REMOVED;
        /* Only ENOENT gets here, and that's ok. */
        status=0;
    }
    else
    {
        /* Entry exists. Check for changes. */
        sts->entry_status=ops__stat_to_action(sts, &st);

        /* May we print a '?' ? */
        if ( ((opt__get_int(OPT__CHANGECHECK) & CHCHECK_FILE) && 
                    (sts->entry_status & FS_LIKELY)) ||
                (opt__get_int(OPT__CHANGECHECK) & CHCHECK_ALLFILES) )
        {
            /* If the type changed (symlink => file etc.) there's no 'likely' - 
             * the entry *was* changed.
             * So if we get here, we can check either type - st or sts->st. */
            if (S_ISREG(st.mode) || S_ISLNK(st.mode))
            {
                /* make sure, one way or another */
                STOPIF( cs__compare_file(sts, fullpath, &i), NULL);

                if (i>0)
                    sts->entry_status= (sts->entry_status & ~ FS_LIKELY) | FS_CHANGED;
                else if (i==0)
                    sts->entry_status= sts->entry_status  & ~(FS_LIKELY  | FS_CHANGED);
            }
            /* Directories will be checked later, on finishing their children; 
             * devices have already been checked, and other types are not 
             * allowed. */
        }
    }

    /* Now we've compared we take the new values.
     * Better for display, needed for commit (current values) */
    /* Before an update (and some other operations) we only set 
     * sts->entry_status - to keep the old values intact. */
    if (output)
        *output=st;
    else
        if (action->overwrite_sts_st) sts->st=st;

    DEBUGP("known %s: action=%X, flags=%X, mode=0%o, status=%d",
            fullpath, sts->entry_status, sts->flags, sts->st.mode, status);

    sts->local_mode_packed = MODE_T_to_PACKED(st.mode);

ex:
    return status;
}


inline void ops___set_todo_bits(struct estat *sts)
{
    /* For recursive operation: If we should do the parent completely, we do 
     * the sub-entries, too. */
    if (opt_recursive>0)
        sts->do_userselected |= sts->parent->do_userselected;
    /* For semi-recursive operation: Do the child, if the parent was 
     * wanted. */
    if (opt_recursive>=0)
        sts->do_this_entry |= sts->parent->do_userselected | sts->do_userselected;
}


void ops__set_todo_bits(struct estat *sts)
{
    /* We don't know any better yet. */
    sts->do_filter_allows=1;
    sts->do_filter_allows_done=1;

    if (sts->parent)
        ops___set_todo_bits(sts);

    DEBUGP("user_sel,this=%d.%d parent=%d.%d", 
            sts->do_userselected, 
            sts->do_this_entry,
            sts->parent ? sts->parent->do_userselected : 0,
            sts->parent ? sts->parent->do_this_entry : 0);

    return;
}


int ops__update_filter_set_bits(struct estat *sts)
{
    int status;
    struct sstat_t stat;

    status=0;

    if (sts->parent)
        ops__set_todo_bits(sts);

    if (sts->do_this_entry)
    {
        STOPIF( ops__update_single_entry(sts, &stat), NULL);

        if (ops__calc_filter_bit(sts))
        {
            /* We'd have an invalid value if the entry is removed. */
            if ((sts->entry_status & FS_REPLACED) != FS_REMOVED)
                if (action->overwrite_sts_st)
                    sts->st = stat;
        }
    }

    DEBUGP("filter says %d", sts->do_filter_allows);

ex:
    return status;
}

void ops__copy_single_entry(struct estat *src, struct estat *dest)
{
    dest->st=src->st;

    dest->repos_rev=SVN_INVALID_REVNUM;
    /* parent is kept */
    /* name is kept */

    /* But, it being a non-committed entry, it has no URL yet. */
    dest->url=NULL;


    if (S_ISDIR(dest->st.mode))
    {
#if 0
        /* Currently unused. */
        dest->by_inode=NULL;
        dest->by_name=NULL;
        dest->entry_count=0;
        dest->strings=NULL;
        dest->other_revs=0;
        dest->to_be_sorted=0;
#endif
    }
    else
    {
        memcpy(dest->md5, src->md5, sizeof(dest->md5));
#if 0
        {
            memset(dest->md5, 0, sizeof(dest->md5));
            /* Currently unused. */
            dest->change_flag=CF_NOTCHANGED;
            dest->decoder=src->decoder;
            dest->has_orig_md5=src->has_orig_md5;
        }
#endif
    }

#if 0
    /* The temporary area is mostly void, but to be on the safe side ... */
    dest->child_index=0;
    dest->dir_pool=NULL;
#endif

    dest->flags=RF_ISNEW | RF_COPY_SUB;

    /* Gets recalculated on next using */
    dest->path_len=0;

    /* The entry is not marked as to-be-ignored ... that would change the 
     * entry type, and we have to save it anyway. */
    dest->entry_status=FS_NEW;
    dest->remote_status=FS_NEW;

    dest->cache_index=0;
    dest->decoder_is_correct=src->decoder_is_correct;

    dest->was_output=0;
    dest->do_userselected = dest->do_child_wanted = dest->do_this_entry = 0;
    dest->arg=NULL;
}


int ops__correlate_dirs(struct estat *dir_A, struct estat *dir_B,
        ops__correlate_fn1_t only_A,
        ops__correlate_fn2_t both,
        ops__correlate_fn1_t only_B,
        ops__correlate_fn2_t for_every)
{
    int status, comp;
    struct estat **list_A, **list_B;


    status=0;
    DEBUGP("correlating %s and %s", dir_A->name, dir_B->name);

    /* We compare the sorted list of entries. */
    STOPIF( dir__sortbyname(dir_A), NULL);
    STOPIF( dir__sortbyname(dir_B), NULL);

    list_A=dir_A->by_name;
    list_B=dir_B->by_name;

    while (*list_A)
    {
        if (!*list_B) goto a_only;

        comp=dir___f_sort_by_name( list_A, list_B );
        DEBUGP("comp %s, %s => %d", 
                (*list_A)->name,
                (*list_B)->name, comp);

        if (comp == 0)
        {
            /* Identical names */
            if (both) 
                STOPIF( both(*list_A, *list_B), NULL);
            if (for_every) 
                STOPIF( for_every(*list_A, *list_B), NULL);

            list_A++;
            list_B++;
        }
        else if (comp > 0)
        {
            /* *list_B > *list_A; entry is additional in list_B. */
            if (only_B) 
                STOPIF( only_B(*list_B, list_B), NULL);
            if (for_every) 
                STOPIF( for_every(NULL, *list_B), NULL);

            list_B++;
        }
        else
        {
a_only:
            /* *list_A < *list_B; so this entry does not exist in dir_B. */
            if (only_A) 
                STOPIF( only_A(*list_A, list_A), NULL);
            if (for_every) 
                STOPIF( for_every(*list_A, NULL), NULL);

            list_A++;
        }
    }

    /* Do remaining list_B entries, if necessary. */
    if (only_B || for_every)
    {
        while (*list_B)
        {
            if (only_B) 
                STOPIF( only_B(*list_B, list_B), NULL);
            if (for_every) 
                STOPIF( for_every(NULL, *list_B), NULL);

            list_B++;
        }
    }

ex:
    return status;
}


/* mmap() might be a bit faster; but for securities' sake we put a \0 at 
 * the end, which might not be possible with a readonly mapping (although 
 * it should be, by using MAP_PRIVATE - but that isn't available with 
 * apr_mmap_create(), at least with 1.2.12).  */
int ops__read_special_entry(apr_file_t *a_stream,
        char **data,
        int max, ssize_t *real_len,
        char *filename,
        apr_pool_t *pool)
{
    int status;
    apr_off_t special_len, bof;
    apr_size_t len_read;
    char *special_data;


    status=0;
    special_len=0;


    /* Remove temporary file. Can be done here because we still have the 
     * handle open.  */
    if (filename)
        STOPIF_CODE_ERR( unlink(filename) == -1, errno,
                "Cannot remove temporary file \"%s\"", filename);


    /* Get length */
    STOPIF( apr_file_seek(a_stream, APR_CUR, &special_len), NULL);

    /* Some arbitrary limit ... */
    if (!max) max=8192;
    STOPIF_CODE_ERR( special_len > max, E2BIG, 
            "!The special entry \"%s\" is too long (%llu bytes, max %llu).\n"
            "Please contact the dev@ mailing list.",
            filename, (t_ull)special_len, (t_ull)max);


    /* Rewind */
    bof=0;
    STOPIF( apr_file_seek(a_stream, APR_SET, &bof), NULL);

    if (pool)
        /* Aborts if no memory available. */
        special_data= apr_palloc( pool, special_len+1);
    else
        STOPIF( hlp__alloc( &special_data, special_len+1), NULL);


    /* Read data. */
    len_read=special_len;
    STOPIF( apr_file_read( a_stream, special_data, &len_read), NULL);
    STOPIF_CODE_ERR( len_read != special_len, ENODATA, 
            "Reading was cut off at byte %llu of %llu",
            (t_ull)len_read, (t_ull)special_len);
    special_data[len_read]=0;

    DEBUGP("got special value %s", special_data);

    if (real_len) *real_len=special_len;
    *data=special_data;

ex:
    return status;
}


int ops__are_children_interesting(struct estat *dir)
{
    struct estat tmp;

    tmp.parent=dir;
    tmp.do_this_entry = tmp.do_userselected = tmp.do_child_wanted = 0;

    ops___set_todo_bits(&tmp);

    return tmp.do_this_entry;
}


int ops__apply_group(struct estat *sts, hash_t *props, 
        apr_pool_t *pool)
{
    int status;
    struct grouping_t *group;
    int own_pool;


    status=0;
    own_pool=0;
    if (props) *props=NULL;

    if (!sts->match_pattern) goto return_prop;

    group= sts->match_pattern->group_def;
    BUG_ON(!group);

    DEBUGP("applying %s to %s", sts->match_pattern->group_name, sts->name);

    if (group->auto_props)
    {
        if (!pool)
        {
            own_pool=1;
            STOPIF( apr_pool_create_ex(&pool, global_pool, NULL, NULL), NULL);
        }

        STOPIF( prp__set_from_aprhash(sts, group->auto_props, 
                    STORE_IN_FS, props, pool), NULL);
        sts->flags |= RF_PUSHPROPS;
    }

    if (!sts->url)
        sts->url=group->url;
    sts->to_be_ignored=group->is_ignore;

    sts->match_pattern=NULL;

return_prop:
    if (props && !*props)
        STOPIF( prp__open_byestat( sts, GDBM_WRCREAT, props), NULL);

ex:
    if (own_pool)
        apr_pool_destroy(pool);

    return status;
}


int ops__make_shadow_entry(struct estat *sts, int flags)
{
    int status;
    struct estat *copy;


    BUG_ON(sts->old);

    STOPIF( ops__allocate(1, &copy, NULL), NULL);
    memcpy(copy, sts, sizeof(*copy));

    if (flags == SHADOWED_BY_REMOTE)
    {
        sts->remote_status=FS_REPLACED;
        copy->remote_status=FS_REMOVED;
    }
    else if (flags == SHADOWED_BY_LOCAL)
    {
        sts->remote_status=FS_REMOVED;
        copy->remote_status=FS_REPLACED;
    }

    /* The by_inode and by_name arrays of the parent might point to the old 
     * location; rather than searching and changing them, we simply copy the 
     * old data, and clean the references in sts. */
    copy->cache_index=0;
    sts->old=copy;

ex:
    return status;
}


#ifndef ENABLE_RELEASE

void DEBUGP_dump_estat(struct estat *sts)
{
    char *path;

    /* We don't want to return failures (like ENOMEM), because then this 
     * function would have to be wrapped in STOPIF(), which would look ugly 
     * compared to the other DEBUGP() calls.
     * So if we can't get the path we just use some part of the filename. */
    /* We could also use
     *   char path[sts->path_len+2];
     *   ops__build_path2(...)
     * which cannot return an ENOMEM, but would always recompute the path 
     * (and not use the cache). */
    if (ops__build_path(&path, sts))
        DEBUGP("*** Dump of ... %s/%s",
                sts->parent ? sts->parent->name : "/",
                sts->name);
    else
        DEBUGP("*** Dump of %s", path);

    DEBUGP("flags=%s", st__flags_string_fromint(sts->flags));
    DEBUGP("entry_status=%s", st__status_string_fromint(sts->entry_status));
    DEBUGP("remote_status=%s", st__status_string_fromint(sts->remote_status));

    DEBUGP("types: st=%s, local=%s, new=%s, old=%s",
                st__type_string(sts->st.mode),
                st__type_string(PACKED_to_MODE_T(sts->local_mode_packed)),
                st__type_string(PACKED_to_MODE_T(sts->new_rev_mode_packed)),
                st__type_string(PACKED_to_MODE_T(sts->old_rev_mode_packed)));

    if (S_ISDIR(sts->st.mode))
        DEBUGP("directory: %d children", sts->entry_count);
    else
        DEBUGP("non-dir: decoder=%s, md5=%s", sts->decoder,
                cs__md5tohex_buffered(sts->md5));

    /* Devices are not seen that often; so we accept a bogus size output. */
    DEBUGP("mode=0%o size=%llu uid=%u gid=%u inode=%llu",
            sts->st.mode & 07777, (t_ull)sts->st.size, 
            sts->st.uid, sts->st.gid,
            (t_ull)sts->st.ino);

    DEBUGP("others:%s%s%s%s%s%s%s%s%s",
            sts->old ? " old" : "",
            sts->was_output ? " was_output" : "",
            sts->decoder_is_correct ? " decoder_ok" : "",
            sts->do_userselected ? " do_usersel" : "",
            sts->do_child_wanted ? " do_chld_w" : "",
            sts->do_this_entry ? " do_this" : "",
            sts->do_filter_allows ? " filter_allows" : "",
            sts->do_filter_allows_done ? " filter_allows_done" : "",
            sts->to_be_ignored ? " ignored" : "");
}
#endif

---