Do more path cleaning in add_implied_include(); make u.slash_cnt more accurate.

[thirdparty/rsync.git] / exclude.c

/*
 * The filter include/exclude routines.
 *
 * Copyright (C) 1996-2001 Andrew Tridgell <tridge@samba.org>
 * Copyright (C) 1996 Paul Mackerras
 * Copyright (C) 2002 Martin Pool
 * Copyright (C) 2003-2022 Wayne Davison
 *
 * 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, visit the http://fsf.org website.
 */

#include "rsync.h"
#include "ifuncs.h"

extern int am_server;
extern int am_sender;
extern int am_generator;
extern int eol_nulls;
extern int io_error;
extern int xfer_dirs;
extern int recurse;
extern int local_server;
extern int prune_empty_dirs;
extern int ignore_perishable;
extern int relative_paths;
extern int delete_mode;
extern int delete_excluded;
extern int cvs_exclude;
extern int sanitize_paths;
extern int protocol_version;
extern int trust_sender_args;
extern int module_id;

extern char curr_dir[MAXPATHLEN];
extern unsigned int curr_dir_len;
extern unsigned int module_dirlen;

filter_rule_list filter_list = { .debug_type = "" };
filter_rule_list cvs_filter_list = { .debug_type = " [global CVS]" };
filter_rule_list daemon_filter_list = { .debug_type = " [daemon]" };
filter_rule_list implied_filter_list = { .debug_type = " [implied]" };

int saw_xattr_filter = 0;
int trust_sender_args = 0;
int trust_sender_filter = 0;

/* Need room enough for ":MODS " prefix plus some room to grow. */
#define MAX_RULE_PREFIX (16)

#define SLASH_WILD3_SUFFIX "/***"

/* The dirbuf is set by push_local_filters() to the current subdirectory
 * relative to curr_dir that is being processed.  The path always has a
 * trailing slash appended, and the variable dirbuf_len contains the length
 * of this path prefix.  The path is always absolute. */
static char dirbuf[MAXPATHLEN+1];
static unsigned int dirbuf_len = 0;
static int dirbuf_depth;

/* This is True when we're scanning parent dirs for per-dir merge-files. */
static BOOL parent_dirscan = False;

/* This array contains a list of all the currently active per-dir merge
 * files.  This makes it easier to save the appropriate values when we
 * "push" down into each subdirectory. */
static filter_rule **mergelist_parents;
static int mergelist_cnt = 0;
static int mergelist_size = 0;

/* Each filter_list_struct describes a singly-linked list by keeping track
 * of both the head and tail pointers.  The list is slightly unusual in that
 * a parent-dir's content can be appended to the end of the local list in a
 * special way:  the last item in the local list has its "next" pointer set
 * to point to the inherited list, but the local list's tail pointer points
 * at the end of the local list.  Thus, if the local list is empty, the head
 * will be pointing at the inherited content but the tail will be NULL.  To
 * help you visualize this, here are the possible list arrangements:
 *
 * Completely Empty                     Local Content Only
 * ==================================   ====================================
 * head -> NULL                         head -> Local1 -> Local2 -> NULL
 * tail -> NULL                         tail -------------^
 *
 * Inherited Content Only               Both Local and Inherited Content
 * ==================================   ====================================
 * head -> Parent1 -> Parent2 -> NULL   head -> L1 -> L2 -> P1 -> P2 -> NULL
 * tail -> NULL                         tail ---------^
 *
 * This means that anyone wanting to traverse the whole list to use it just
 * needs to start at the head and use the "next" pointers until it goes
 * NULL.  To add new local content, we insert the item after the tail item
 * and update the tail (obviously, if "tail" was NULL, we insert it at the
 * head).  To clear the local list, WE MUST NOT FREE THE INHERITED CONTENT
 * because it is shared between the current list and our parent list(s).
 * The easiest way to handle this is to simply truncate the list after the
 * tail item and then free the local list from the head.  When inheriting
 * the list for a new local dir, we just save off the filter_list_struct
 * values (so we can pop back to them later) and set the tail to NULL.
 */

static void teardown_mergelist(filter_rule *ex)
{
        int j;

        if (!ex->u.mergelist)
                return;

        if (DEBUG_GTE(FILTER, 2)) {
                rprintf(FINFO, "[%s] deactivating mergelist #%d%s\n",
                        who_am_i(), mergelist_cnt - 1,
                        ex->u.mergelist->debug_type);
        }

        free(ex->u.mergelist->debug_type);
        free(ex->u.mergelist);

        for (j = 0; j < mergelist_cnt; j++) {
                if (mergelist_parents[j] == ex) {
                        mergelist_parents[j] = NULL;
                        break;
                }
        }
        while (mergelist_cnt && mergelist_parents[mergelist_cnt-1] == NULL)
                mergelist_cnt--;
}

static void free_filter(filter_rule *ex)
{
        if (ex->rflags & FILTRULE_PERDIR_MERGE)
                teardown_mergelist(ex);
        free(ex->pattern);
        free(ex);
}

static void free_filters(filter_rule *ent)
{
        while (ent) {
                filter_rule *next = ent->next;
                free_filter(ent);
                ent = next;
        }
}

/* Build a filter structure given a filter pattern.  The value in "pat"
 * is not null-terminated.  "rule" is either held or freed, so the
 * caller should not free it. */
static void add_rule(filter_rule_list *listp, const char *pat, unsigned int pat_len,
                     filter_rule *rule, int xflags)
{
        const char *cp;
        unsigned int pre_len, suf_len, slash_cnt = 0;
        char *mention_rule_suffix;

        if (DEBUG_GTE(FILTER, 1) && pat_len && (pat[pat_len-1] == ' ' || pat[pat_len-1] == '\t'))
                mention_rule_suffix = " -- CAUTION: trailing whitespace!";
        else
                mention_rule_suffix = DEBUG_GTE(FILTER, 2) ? "" : NULL;
        if (mention_rule_suffix) {
                rprintf(FINFO, "[%s] add_rule(%s%.*s%s)%s%s\n",
                        who_am_i(), get_rule_prefix(rule, pat, 0, NULL),
                        (int)pat_len, pat, (rule->rflags & FILTRULE_DIRECTORY) ? "/" : "",
                        listp->debug_type, mention_rule_suffix);
        }

        /* These flags also indicate that we're reading a list that
         * needs to be filtered now, not post-filtered later. */
        if (xflags & (XFLG_ANCHORED2ABS|XFLG_ABS_IF_SLASH)
                && (rule->rflags & FILTRULES_SIDES)
                        == (am_sender ? FILTRULE_RECEIVER_SIDE : FILTRULE_SENDER_SIDE)) {
                /* This filter applies only to the other side.  Drop it. */
                free_filter(rule);
                return;
        }

        if (pat_len > 1 && pat[pat_len-1] == '/') {
                pat_len--;
                rule->rflags |= FILTRULE_DIRECTORY;
        }

        for (cp = pat; cp < pat + pat_len; cp++) {
                if (*cp == '/')
                        slash_cnt++;
        }

        if (!(rule->rflags & (FILTRULE_ABS_PATH | FILTRULE_MERGE_FILE))
         && ((xflags & (XFLG_ANCHORED2ABS|XFLG_ABS_IF_SLASH) && *pat == '/')
          || (xflags & XFLG_ABS_IF_SLASH && slash_cnt))) {
                rule->rflags |= FILTRULE_ABS_PATH;
                if (*pat == '/')
                        pre_len = dirbuf_len - module_dirlen - 1;
                else
                        pre_len = 0;
        } else
                pre_len = 0;

        /* The daemon wants dir-exclude rules to get an appended "/" + "***". */
        if (xflags & XFLG_DIR2WILD3
         && BITS_SETnUNSET(rule->rflags, FILTRULE_DIRECTORY, FILTRULE_INCLUDE)) {
                rule->rflags &= ~FILTRULE_DIRECTORY;
                suf_len = sizeof SLASH_WILD3_SUFFIX - 1;
        } else
                suf_len = 0;

        rule->pattern = new_array(char, pre_len + pat_len + suf_len + 1);
        if (pre_len) {
                memcpy(rule->pattern, dirbuf + module_dirlen, pre_len);
                for (cp = rule->pattern; cp < rule->pattern + pre_len; cp++) {
                        if (*cp == '/')
                                slash_cnt++;
                }
        }
        strlcpy(rule->pattern + pre_len, pat, pat_len + 1);
        pat_len += pre_len;
        if (suf_len) {
                memcpy(rule->pattern + pat_len, SLASH_WILD3_SUFFIX, suf_len+1);
                pat_len += suf_len;
                slash_cnt++;
        }

        if (strpbrk(rule->pattern, "*[?")) {
                rule->rflags |= FILTRULE_WILD;
                if ((cp = strstr(rule->pattern, "**")) != NULL) {
                        rule->rflags |= FILTRULE_WILD2;
                        /* If the pattern starts with **, note that. */
                        if (cp == rule->pattern)
                                rule->rflags |= FILTRULE_WILD2_PREFIX;
                        /* If the pattern ends with ***, note that. */
                        if (pat_len >= 3
                         && rule->pattern[pat_len-3] == '*'
                         && rule->pattern[pat_len-2] == '*'
                         && rule->pattern[pat_len-1] == '*')
                                rule->rflags |= FILTRULE_WILD3_SUFFIX;
                }
        }

        if (rule->rflags & FILTRULE_PERDIR_MERGE) {
                filter_rule_list *lp;
                unsigned int len;
                int i;

                if ((cp = strrchr(rule->pattern, '/')) != NULL)
                        cp++;
                else
                        cp = rule->pattern;

                /* If the local merge file was already mentioned, don't
                 * add it again. */
                for (i = 0; i < mergelist_cnt; i++) {
                        filter_rule *ex = mergelist_parents[i];
                        const char *s;
                        if (!ex)
                                continue;
                        s = strrchr(ex->pattern, '/');
                        if (s)
                                s++;
                        else
                                s = ex->pattern;
                        len = strlen(s);
                        if (len == pat_len - (cp - rule->pattern) && memcmp(s, cp, len) == 0) {
                                free_filter(rule);
                                return;
                        }
                }

                lp = new_array0(filter_rule_list, 1);
                if (asprintf(&lp->debug_type, " [per-dir %s]", cp) < 0)
                        out_of_memory("add_rule");
                rule->u.mergelist = lp;

                if (mergelist_cnt == mergelist_size) {
                        mergelist_size += 5;
                        mergelist_parents = realloc_array(mergelist_parents, filter_rule *, mergelist_size);
                }
                if (DEBUG_GTE(FILTER, 2)) {
                        rprintf(FINFO, "[%s] activating mergelist #%d%s\n",
                                who_am_i(), mergelist_cnt, lp->debug_type);
                }
                mergelist_parents[mergelist_cnt++] = rule;
        } else
                rule->u.slash_cnt = slash_cnt;

        if (!listp->tail) {
                rule->next = listp->head;
                listp->head = listp->tail = rule;
        } else {
                rule->next = listp->tail->next;
                listp->tail->next = rule;
                listp->tail = rule;
        }
}

/* If the wildcards failed, the remote shell might give us a file matching the literal
 * wildcards.  Since "*" & "?" already match themselves, this just needs to deal with
 * failed "[foo]" idioms.
 */
static void maybe_add_literal_brackets_rule(filter_rule const *based_on, int arg_len)
{
        filter_rule *rule;
        const char *arg = based_on->pattern, *cp;
        char *p;
        int cnt = 0;

        if (arg_len < 0)
                arg_len = strlen(arg);

        for (cp = arg; *cp; cp++) {
                if (*cp == '\\' && cp[1]) {
                        cp++;
                } else if (*cp == '[')
                        cnt++;
        }
        if (!cnt)
                return;

        rule = new0(filter_rule);
        rule->rflags = based_on->rflags;
        rule->u.slash_cnt = based_on->u.slash_cnt;
        p = rule->pattern = new_array(char, arg_len + cnt + 1);
        for (cp = arg; *cp; ) {
                if (*cp == '\\' && cp[1]) {
                        *p++ = *cp++;
                } else if (*cp == '[')
                        *p++ = '\\';
                *p++ = *cp++;
        }
        *p++ = '\0';

        rule->next = implied_filter_list.head;
        implied_filter_list.head = rule;
        if (DEBUG_GTE(FILTER, 3)) {
                rprintf(FINFO, "[%s] add_implied_include(%s%s)\n", who_am_i(), rule->pattern,
                        rule->rflags & FILTRULE_DIRECTORY ? "/" : "");
        }
}

static char *partial_string_buf = NULL;
static int partial_string_len = 0;
void implied_include_partial_string(const char *s_start, const char *s_end)
{
        partial_string_len = s_end - s_start;
        if (partial_string_len <= 0 || partial_string_len >= MAXPATHLEN) { /* too-large should be impossible... */
                partial_string_len = 0;
                return;
        }
        if (!partial_string_buf)
                partial_string_buf = new_array(char, MAXPATHLEN);
        memcpy(partial_string_buf, s_start, partial_string_len);
}

void free_implied_include_partial_string()
{
        if (partial_string_buf) {
                free(partial_string_buf);
                partial_string_buf = NULL;
        }
        partial_string_len = 0; /* paranoia */
}

/* Each arg the client sends to the remote sender turns into an implied include
 * that the receiver uses to validate the file list from the sender. */
void add_implied_include(const char *arg, int skip_daemon_module)
{
        int arg_len, saw_wild = 0, saw_live_open_brkt = 0, backslash_cnt = 0;
        int slash_cnt = 0; /* We know we're adding a leading slash. */
        const char *cp;
        char *p;
        if (trust_sender_args)
                return;
        if (partial_string_len) {
                arg_len = strlen(arg);
                if (partial_string_len + arg_len >= MAXPATHLEN) {
                        partial_string_len = 0;
                        return; /* Should be impossible... */
                }
                memcpy(partial_string_buf + partial_string_len, arg, arg_len + 1);
                partial_string_len = 0;
                arg = partial_string_buf;
        }
        if (skip_daemon_module) {
                if ((cp = strchr(arg, '/')) != NULL)
                        arg = cp + 1;
                else
                        arg = "";
        }
        if (relative_paths) {
                if ((cp = strstr(arg, "/./")) != NULL)
                        arg = cp + 3;
        } else if ((cp = strrchr(arg, '/')) != NULL) {
                arg = cp + 1;
        }
        if (*arg == '.' && arg[1] == '\0')
                arg++;
        arg_len = strlen(arg);
        if (arg_len) {
                char *new_pat;
                if (strpbrk(arg, "*[?")) {
                        /* We need to add room to escape backslashes if wildcard chars are present. */
                        for (cp = arg; (cp = strchr(cp, '\\')) != NULL; cp++)
                                arg_len++;
                        saw_wild = 1;
                }
                arg_len++; /* Leave room for the prefixed slash */
                p = new_pat = new_array(char, arg_len + 1);
                *p++ = '/';
                slash_cnt++;
                for (cp = arg; *cp; ) {
                        switch (*cp) {
                          case '\\':
                                if (cp[1] == ']') {
                                        if (!saw_wild)
                                                cp++; /* A \] in a non-wild filter causes a problem, so drop the \ . */
                                } else if (!strchr("*[?", cp[1])) {
                                        backslash_cnt++;
                                        if (saw_wild)
                                                *p++ = '\\';
                                }
                                *p++ = *cp++;
                                break;
                          case '/':
                                if (p[-1] == '/') { /* This is safe because of the initial slash. */
                                        if (*++cp == '\0') {
                                                slash_cnt--;
                                                p--;
                                        }
                                } else if (cp[1] == '\0') {
                                        cp++;
                                } else {
                                        slash_cnt++;
                                        *p++ = *cp++;
                                }
                                break;
                          case '.':
                                if (p[-1] == '/') {
                                        if (cp[1] == '/') {
                                                cp += 2;
                                                if (!*cp) {
                                                        slash_cnt--;
                                                        p--;
                                                }
                                        } else if (cp[1] == '\0') {
                                                cp++;
                                                slash_cnt--;
                                                p--;
                                                break;
                                        }
                                } else
                                        *p++ = *cp++;
                                break;
                          case '[':
                                saw_live_open_brkt = 1;
                                *p++ = *cp++;
                                break;
                          default:
                                *p++ = *cp++;
                                break;
                        }
                }
                *p = '\0';
                arg_len = p - new_pat;
                if (!arg_len)
                        free(new_pat);
                else {
                        filter_rule *rule = new0(filter_rule);
                        rule->rflags = FILTRULE_INCLUDE + (saw_wild ? FILTRULE_WILD : 0);
                        rule->u.slash_cnt = slash_cnt;
                        arg = rule->pattern = new_pat;
                        if (!implied_filter_list.head)
                                implied_filter_list.head = implied_filter_list.tail = rule;
                        else {
                                rule->next = implied_filter_list.head;
                                implied_filter_list.head = rule;
                        }
                        if (DEBUG_GTE(FILTER, 3))
                                rprintf(FINFO, "[%s] add_IMPlied_include(%s)\n", who_am_i(), arg);
                        if (saw_live_open_brkt)
                                maybe_add_literal_brackets_rule(rule, arg_len);
                        if (relative_paths && slash_cnt) {
                                filter_rule const *ent;
                                int found = 0;
                                slash_cnt = 1;
                                for (p = new_pat + 1; (p = strchr(p, '/')) != NULL; p++) {
                                        *p = '\0';
                                        for (ent = implied_filter_list.head; ent; ent = ent->next) {
                                                if (ent != rule && strcmp(ent->pattern, new_pat) == 0) {
                                                        found = 1;
                                                        break;
                                                }
                                        }
                                        if (!found) {
                                                filter_rule *R_rule = new0(filter_rule);
                                                R_rule->rflags = FILTRULE_INCLUDE | FILTRULE_DIRECTORY;
                                                /* Check if our sub-path has wildcards or escaped backslashes */
                                                if (saw_wild && strpbrk(rule->pattern, "*[?\\"))
                                                        R_rule->rflags |= FILTRULE_WILD;
                                                R_rule->pattern = strdup(new_pat);
                                                R_rule->u.slash_cnt = slash_cnt;
                                                R_rule->next = implied_filter_list.head;
                                                implied_filter_list.head = R_rule;
                                                if (DEBUG_GTE(FILTER, 3)) {
                                                        rprintf(FINFO, "[%s] add_implied_include(%s/)\n",
                                                                who_am_i(), R_rule->pattern);
                                                }
                                                if (saw_live_open_brkt)
                                                        maybe_add_literal_brackets_rule(R_rule, -1);
                                        }
                                        *p = '/';
                                        slash_cnt++;
                                }
                        }
                }
        }

        if (recurse || xfer_dirs) {
                /* Now create a rule with an added "/" & "**" or "*" at the end */
                filter_rule *rule = new0(filter_rule);
                rule->rflags = FILTRULE_INCLUDE | FILTRULE_WILD;
                if (recurse)
                        rule->rflags |= FILTRULE_WILD2;
                /* We must leave enough room for / * * \0. */
                if (!saw_wild && backslash_cnt) {
                        /* We are appending a wildcard, so now the backslashes need to be escaped. */
                        p = rule->pattern = new_array(char, arg_len + backslash_cnt + 3 + 1);
                        for (cp = arg; *cp; ) { /* Note that arg_len != 0 because backslash_cnt > 0 */
                                if (*cp == '\\')
                                        *p++ = '\\';
                                *p++ = *cp++;
                        }
                } else {
                        p = rule->pattern = new_array(char, arg_len + 3 + 1);
                        if (arg_len) {
                                memcpy(p, arg, arg_len);
                                p += arg_len;
                        }
                }
                if (p[-1] != '/') {
                        *p++ = '/';
                        slash_cnt++;
                }
                *p++ = '*';
                if (recurse)
                        *p++ = '*';
                *p = '\0';
                rule->u.slash_cnt = slash_cnt;
                rule->next = implied_filter_list.head;
                implied_filter_list.head = rule;
                if (DEBUG_GTE(FILTER, 3))
                        rprintf(FINFO, "[%s] add_implied_include(%s)\n", who_am_i(), rule->pattern);
                if (saw_live_open_brkt)
                        maybe_add_literal_brackets_rule(rule, p - rule->pattern);
        }
}

/* This frees any non-inherited items, leaving just inherited items on the list. */
static void pop_filter_list(filter_rule_list *listp)
{
        filter_rule *inherited;

        if (!listp->tail)
                return;

        inherited = listp->tail->next;

        /* Truncate any inherited items from the local list. */
        listp->tail->next = NULL;
        /* Now free everything that is left. */
        free_filters(listp->head);

        listp->head = inherited;
        listp->tail = NULL;
}

/* This returns an expanded (absolute) filename for the merge-file name if
 * the name has any slashes in it OR if the parent_dirscan var is True;
 * otherwise it returns the original merge_file name.  If the len_ptr value
 * is non-NULL the merge_file name is limited by the referenced length
 * value and will be updated with the length of the resulting name.  We
 * always return a name that is null terminated, even if the merge_file
 * name was not. */
static char *parse_merge_name(const char *merge_file, unsigned int *len_ptr,
                              unsigned int prefix_skip)
{
        static char buf[MAXPATHLEN];
        char *fn, tmpbuf[MAXPATHLEN];
        unsigned int fn_len;

        if (!parent_dirscan && *merge_file != '/') {
                /* Return the name unchanged it doesn't have any slashes. */
                if (len_ptr) {
                        const char *p = merge_file + *len_ptr;
                        while (--p > merge_file && *p != '/') {}
                        if (p == merge_file) {
                                strlcpy(buf, merge_file, *len_ptr + 1);
                                return buf;
                        }
                } else if (strchr(merge_file, '/') == NULL)
                        return (char *)merge_file;
        }

        fn = *merge_file == '/' ? buf : tmpbuf;
        if (sanitize_paths) {
                const char *r = prefix_skip ? "/" : NULL;
                /* null-terminate the name if it isn't already */
                if (len_ptr && merge_file[*len_ptr]) {
                        char *to = fn == buf ? tmpbuf : buf;
                        strlcpy(to, merge_file, *len_ptr + 1);
                        merge_file = to;
                }
                if (!sanitize_path(fn, merge_file, r, dirbuf_depth, SP_DEFAULT)) {
                        rprintf(FERROR, "merge-file name overflows: %s\n",
                                merge_file);
                        return NULL;
                }
                fn_len = strlen(fn);
        } else {
                strlcpy(fn, merge_file, len_ptr ? *len_ptr + 1 : MAXPATHLEN);
                fn_len = clean_fname(fn, CFN_COLLAPSE_DOT_DOT_DIRS);
        }

        /* If the name isn't in buf yet, it wasn't absolute. */
        if (fn != buf) {
                int d_len = dirbuf_len - prefix_skip;
                if (d_len + fn_len >= MAXPATHLEN) {
                        rprintf(FERROR, "merge-file name overflows: %s\n", fn);
                        return NULL;
                }
                memcpy(buf, dirbuf + prefix_skip, d_len);
                memcpy(buf + d_len, fn, fn_len + 1);
                fn_len = clean_fname(buf, CFN_COLLAPSE_DOT_DOT_DIRS);
        }

        if (len_ptr)
                *len_ptr = fn_len;
        return buf;
}

/* Sets the dirbuf and dirbuf_len values. */
void set_filter_dir(const char *dir, unsigned int dirlen)
{
        unsigned int len;
        if (*dir != '/') {
                memcpy(dirbuf, curr_dir, curr_dir_len);
                dirbuf[curr_dir_len] = '/';
                len = curr_dir_len + 1;
                if (len + dirlen >= MAXPATHLEN)
                        dirlen = 0;
        } else
                len = 0;
        memcpy(dirbuf + len, dir, dirlen);
        dirbuf[dirlen + len] = '\0';
        dirbuf_len = clean_fname(dirbuf, CFN_COLLAPSE_DOT_DOT_DIRS);
        if (dirbuf_len > 1 && dirbuf[dirbuf_len-1] == '.'
            && dirbuf[dirbuf_len-2] == '/')
                dirbuf_len -= 2;
        if (dirbuf_len != 1)
                dirbuf[dirbuf_len++] = '/';
        dirbuf[dirbuf_len] = '\0';
        if (sanitize_paths)
                dirbuf_depth = count_dir_elements(dirbuf + module_dirlen);
}

/* This routine takes a per-dir merge-file entry and finishes its setup.
 * If the name has a path portion then we check to see if it refers to a
 * parent directory of the first transfer dir.  If it does, we scan all the
 * dirs from that point through the parent dir of the transfer dir looking
 * for the per-dir merge-file in each one. */
static BOOL setup_merge_file(int mergelist_num, filter_rule *ex,
                             filter_rule_list *lp)
{
        char buf[MAXPATHLEN];
        char *x, *y, *pat = ex->pattern;
        unsigned int len;

        if (!(x = parse_merge_name(pat, NULL, 0)) || *x != '/')
                return 0;

        if (DEBUG_GTE(FILTER, 2)) {
                rprintf(FINFO, "[%s] performing parent_dirscan for mergelist #%d%s\n",
                        who_am_i(), mergelist_num, lp->debug_type);
        }
        y = strrchr(x, '/');
        *y = '\0';
        ex->pattern = strdup(y+1);
        if (!*x)
                x = "/";
        if (*x == '/')
                strlcpy(buf, x, MAXPATHLEN);
        else
                pathjoin(buf, MAXPATHLEN, dirbuf, x);

        len = clean_fname(buf, CFN_COLLAPSE_DOT_DOT_DIRS);
        if (len != 1 && len < MAXPATHLEN-1) {
                buf[len++] = '/';
                buf[len] = '\0';
        }
        /* This ensures that the specified dir is a parent of the transfer. */
        for (x = buf, y = dirbuf; *x && *x == *y; x++, y++) {}
        if (*x)
                y += strlen(y); /* nope -- skip the scan */

        parent_dirscan = True;
        while (*y) {
                char save[MAXPATHLEN];
                strlcpy(save, y, MAXPATHLEN);
                *y = '\0';
                dirbuf_len = y - dirbuf;
                strlcpy(x, ex->pattern, MAXPATHLEN - (x - buf));
                parse_filter_file(lp, buf, ex, XFLG_ANCHORED2ABS);
                if (ex->rflags & FILTRULE_NO_INHERIT) {
                        /* Free the undesired rules to clean up any per-dir
                         * mergelists they defined.  Otherwise pop_local_filters
                         * may crash trying to restore nonexistent state for
                         * those mergelists. */
                        free_filters(lp->head);
                        lp->head = NULL;
                }
                lp->tail = NULL;
                strlcpy(y, save, MAXPATHLEN);
                while ((*x++ = *y++) != '/') {}
        }
        parent_dirscan = False;
        if (DEBUG_GTE(FILTER, 2)) {
                rprintf(FINFO, "[%s] completed parent_dirscan for mergelist #%d%s\n",
                        who_am_i(), mergelist_num, lp->debug_type);
        }
        free(pat);
        return 1;
}

struct local_filter_state {
        int mergelist_cnt;
        filter_rule_list mergelists[1];
};

/* Each time rsync changes to a new directory it call this function to
 * handle all the per-dir merge-files.  The "dir" value is the current path
 * relative to curr_dir (which might not be null-terminated).  We copy it
 * into dirbuf so that we can easily append a file name on the end. */
void *push_local_filters(const char *dir, unsigned int dirlen)
{
        struct local_filter_state *push;
        int i;

        set_filter_dir(dir, dirlen);
        if (DEBUG_GTE(FILTER, 2)) {
                rprintf(FINFO, "[%s] pushing local filters for %s\n",
                        who_am_i(), dirbuf);
        }

        if (!mergelist_cnt) {
                /* No old state to save and no new merge files to push. */
                return NULL;
        }

        push = (struct local_filter_state *)new_array(char,
                          sizeof (struct local_filter_state)
                        + (mergelist_cnt-1) * sizeof (filter_rule_list));

        push->mergelist_cnt = mergelist_cnt;
        for (i = 0; i < mergelist_cnt; i++) {
                filter_rule *ex = mergelist_parents[i];
                if (!ex)
                        continue;
                memcpy(&push->mergelists[i], ex->u.mergelist, sizeof (filter_rule_list));
        }

        /* Note: parse_filter_file() might increase mergelist_cnt, so keep
         * this loop separate from the above loop. */
        for (i = 0; i < mergelist_cnt; i++) {
                filter_rule *ex = mergelist_parents[i];
                filter_rule_list *lp;
                if (!ex)
                        continue;
                lp = ex->u.mergelist;

                if (DEBUG_GTE(FILTER, 2)) {
                        rprintf(FINFO, "[%s] pushing mergelist #%d%s\n",
                                who_am_i(), i, lp->debug_type);
                }

                lp->tail = NULL; /* Switch any local rules to inherited. */
                if (ex->rflags & FILTRULE_NO_INHERIT)
                        lp->head = NULL;

                if (ex->rflags & FILTRULE_FINISH_SETUP) {
                        ex->rflags &= ~FILTRULE_FINISH_SETUP;
                        if (setup_merge_file(i, ex, lp))
                                set_filter_dir(dir, dirlen);
                }

                if (strlcpy(dirbuf + dirbuf_len, ex->pattern,
                    MAXPATHLEN - dirbuf_len) < MAXPATHLEN - dirbuf_len) {
                        parse_filter_file(lp, dirbuf, ex,
                                          XFLG_ANCHORED2ABS);
                } else {
                        io_error |= IOERR_GENERAL;
                        rprintf(FERROR,
                            "cannot add local filter rules in long-named directory: %s\n",
                            full_fname(dirbuf));
                }
                dirbuf[dirbuf_len] = '\0';
        }

        return (void*)push;
}

void pop_local_filters(void *mem)
{
        struct local_filter_state *pop = (struct local_filter_state *)mem;
        int i;
        int old_mergelist_cnt = pop ? pop->mergelist_cnt : 0;

        if (DEBUG_GTE(FILTER, 2))
                rprintf(FINFO, "[%s] popping local filters\n", who_am_i());

        for (i = mergelist_cnt; i-- > 0; ) {
                filter_rule *ex = mergelist_parents[i];
                filter_rule_list *lp;
                if (!ex)
                        continue;
                lp = ex->u.mergelist;

                if (DEBUG_GTE(FILTER, 2)) {
                        rprintf(FINFO, "[%s] popping mergelist #%d%s\n",
                                who_am_i(), i, lp->debug_type);
                }

                pop_filter_list(lp);
                if (i >= old_mergelist_cnt && lp->head) {
                        /* This mergelist does not exist in the state to be restored, but it
                         * still has inherited rules.  This can sometimes happen if a per-dir
                         * merge file calls setup_merge_file() in push_local_filters() and that
                         * leaves some inherited rules that aren't in the pushed list state. */
                        if (DEBUG_GTE(FILTER, 2)) {
                                rprintf(FINFO, "[%s] freeing parent_dirscan filters of mergelist #%d%s\n",
                                        who_am_i(), i, ex->u.mergelist->debug_type);
                        }
                        pop_filter_list(lp);
                }
        }

        if (!pop)
                return; /* No state to restore. */

        for (i = 0; i < old_mergelist_cnt; i++) {
                filter_rule *ex = mergelist_parents[i];
                if (!ex)
                        continue;
                memcpy(ex->u.mergelist, &pop->mergelists[i], sizeof (filter_rule_list));
        }

        free(pop);
}

void change_local_filter_dir(const char *dname, int dlen, int dir_depth)
{
        static int cur_depth = -1;
        static void *filt_array[MAXPATHLEN/2+1];

        if (!dname) {
                for ( ; cur_depth >= 0; cur_depth--) {
                        if (filt_array[cur_depth]) {
                                pop_local_filters(filt_array[cur_depth]);
                                filt_array[cur_depth] = NULL;
                        }
                }
                return;
        }

        assert(dir_depth < MAXPATHLEN/2+1);

        for ( ; cur_depth >= dir_depth; cur_depth--) {
                if (filt_array[cur_depth]) {
                        pop_local_filters(filt_array[cur_depth]);
                        filt_array[cur_depth] = NULL;
                }
        }

        cur_depth = dir_depth;
        filt_array[cur_depth] = push_local_filters(dname, dlen);
}

static int rule_matches(const char *fname, filter_rule *ex, int name_flags)
{
        int slash_handling, str_cnt = 0, anchored_match = 0;
        int ret_match = ex->rflags & FILTRULE_NEGATE ? 0 : 1;
        char *p, *pattern = ex->pattern;
        const char *strings[16]; /* more than enough */
        const char *name = fname + (*fname == '/');

        if (!*name)
                return 0;

        if (!(name_flags & NAME_IS_XATTR) ^ !(ex->rflags & FILTRULE_XATTR))
                return 0;

        if (!ex->u.slash_cnt && !(ex->rflags & FILTRULE_WILD2)) {
                /* If the pattern does not have any slashes AND it does
                 * not have a "**" (which could match a slash), then we
                 * just match the name portion of the path. */
                if ((p = strrchr(name,'/')) != NULL)
                        name = p+1;
        } else if (ex->rflags & FILTRULE_ABS_PATH && *fname != '/'
            && curr_dir_len > module_dirlen + 1) {
                /* If we're matching against an absolute-path pattern,
                 * we need to prepend our full path info. */
                strings[str_cnt++] = curr_dir + module_dirlen + 1;
                strings[str_cnt++] = "/";
        } else if (ex->rflags & FILTRULE_WILD2_PREFIX && *fname != '/') {
                /* Allow "**"+"/" to match at the start of the string. */
                strings[str_cnt++] = "/";
        }
        strings[str_cnt++] = name;
        if (name_flags & NAME_IS_DIR) {
                /* Allow a trailing "/"+"***" to match the directory. */
                if (ex->rflags & FILTRULE_WILD3_SUFFIX)
                        strings[str_cnt++] = "/";
        } else if (ex->rflags & FILTRULE_DIRECTORY)
                return !ret_match;
        strings[str_cnt] = NULL;

        if (*pattern == '/') {
                anchored_match = 1;
                pattern++;
        }

        if (!anchored_match && ex->u.slash_cnt
            && !(ex->rflags & FILTRULE_WILD2)) {
                /* A non-anchored match with an infix slash and no "**"
                 * needs to match the last slash_cnt+1 name elements. */
                slash_handling = ex->u.slash_cnt + 1;
        } else if (!anchored_match && !(ex->rflags & FILTRULE_WILD2_PREFIX)
                                   && ex->rflags & FILTRULE_WILD2) {
                /* A non-anchored match with an infix or trailing "**" (but not
                 * a prefixed "**") needs to try matching after every slash. */
                slash_handling = -1;
        } else {
                /* The pattern matches only at the start of the path or name. */
                slash_handling = 0;
        }

        if (ex->rflags & FILTRULE_WILD) {
                if (wildmatch_array(pattern, strings, slash_handling))
                        return ret_match;
        } else if (str_cnt > 1) {
                if (litmatch_array(pattern, strings, slash_handling))
                        return ret_match;
        } else if (anchored_match) {
                if (strcmp(name, pattern) == 0)
                        return ret_match;
        } else {
                int l1 = strlen(name);
                int l2 = strlen(pattern);
                if (l2 <= l1 &&
                    strcmp(name+(l1-l2),pattern) == 0 &&
                    (l1==l2 || name[l1-(l2+1)] == '/')) {
                        return ret_match;
                }
        }

        return !ret_match;
}

static void report_filter_result(enum logcode code, char const *name,
                                 filter_rule const *ent,
                                 int name_flags, const char *type)
{
        int log_level = am_sender || am_generator ? 1 : 3;

        /* If a trailing slash is present to match only directories,
         * then it is stripped out by add_rule().  So as a special
         * case we add it back in the log output. */
        if (DEBUG_GTE(FILTER, log_level)) {
                static char *actions[2][2]
                    = { {"show", "hid"}, {"risk", "protect"} };
                const char *w = who_am_i();
                const char *t = name_flags & NAME_IS_XATTR ? "xattr"
                              : name_flags & NAME_IS_DIR ? "directory"
                              : "file";
                rprintf(code, "[%s] %sing %s %s because of pattern %s%s%s\n",
                    w, actions[*w=='g'][!(ent->rflags & FILTRULE_INCLUDE)],
                    t, name, ent->pattern,
                    ent->rflags & FILTRULE_DIRECTORY ? "/" : "", type);
        }
}

/* This function is used to check if a file should be included/excluded
 * from the list of files based on its name and type etc.  The value of
 * filter_level is set to either SERVER_FILTERS or ALL_FILTERS. */
int name_is_excluded(const char *fname, int name_flags, int filter_level)
{
        if (daemon_filter_list.head && check_filter(&daemon_filter_list, FLOG, fname, name_flags) < 0) {
                if (!(name_flags & NAME_IS_XATTR))
                        errno = ENOENT;
                return 1;
        }

        if (filter_level != ALL_FILTERS)
                return 0;

        if (filter_list.head && check_filter(&filter_list, FINFO, fname, name_flags) < 0)
                return 1;

        return 0;
}

/* Return -1 if file "name" is defined to be excluded by the specified
 * exclude list, 1 if it is included, and 0 if it was not matched. */
int check_filter(filter_rule_list *listp, enum logcode code,
                 const char *name, int name_flags)
{
        filter_rule *ent;

        for (ent = listp->head; ent; ent = ent->next) {
                if (ignore_perishable && ent->rflags & FILTRULE_PERISHABLE)
                        continue;
                if (ent->rflags & FILTRULE_PERDIR_MERGE) {
                        int rc = check_filter(ent->u.mergelist, code, name, name_flags);
                        if (rc)
                                return rc;
                        continue;
                }
                if (ent->rflags & FILTRULE_CVS_IGNORE) {
                        int rc = check_filter(&cvs_filter_list, code, name, name_flags);
                        if (rc)
                                return rc;
                        continue;
                }
                if (rule_matches(name, ent, name_flags)) {
                        report_filter_result(code, name, ent, name_flags, listp->debug_type);
                        return ent->rflags & FILTRULE_INCLUDE ? 1 : -1;
                }
        }

        return 0;
}

#define RULE_STRCMP(s,r) rule_strcmp((s), (r), sizeof (r) - 1)

static const uchar *rule_strcmp(const uchar *str, const char *rule, int rule_len)
{
        if (strncmp((char*)str, rule, rule_len) != 0)
                return NULL;
        if (isspace(str[rule_len]) || str[rule_len] == '_' || !str[rule_len])
                return str + rule_len - 1;
        if (str[rule_len] == ',')
                return str + rule_len;
        return NULL;
}

#define FILTRULES_FROM_CONTAINER (FILTRULE_ABS_PATH | FILTRULE_INCLUDE \
                                | FILTRULE_DIRECTORY | FILTRULE_NEGATE \
                                | FILTRULE_PERISHABLE)

/* Gets the next include/exclude rule from *rulestr_ptr and advances
 * *rulestr_ptr to point beyond it.  Stores the pattern's start (within
 * *rulestr_ptr) and length in *pat_ptr and *pat_len_ptr, and returns a newly
 * allocated filter_rule containing the rest of the information.  Returns
 * NULL if there are no more rules in the input.
 *
 * The template provides defaults for the new rule to inherit, and the
 * template rflags and the xflags additionally affect parsing. */
static filter_rule *parse_rule_tok(const char **rulestr_ptr,
                                   const filter_rule *template, int xflags,
                                   const char **pat_ptr, unsigned int *pat_len_ptr)
{
        const uchar *s = (const uchar *)*rulestr_ptr;
        filter_rule *rule;
        unsigned int len;

        if (template->rflags & FILTRULE_WORD_SPLIT) {
                /* Skip over any initial whitespace. */
                while (isspace(*s))
                        s++;
                /* Update to point to real start of rule. */
                *rulestr_ptr = (const char *)s;
        }
        if (!*s)
                return NULL;

        rule = new0(filter_rule);

        /* Inherit from the template.  Don't inherit FILTRULES_SIDES; we check
         * that later. */
        rule->rflags = template->rflags & FILTRULES_FROM_CONTAINER;

        /* Figure out what kind of a filter rule "s" is pointing at.  Note
         * that if FILTRULE_NO_PREFIXES is set, the rule is either an include
         * or an exclude based on the inheritance of the FILTRULE_INCLUDE
         * flag (above).  XFLG_OLD_PREFIXES indicates a compatibility mode
         * for old include/exclude patterns where just "+ " and "- " are
         * allowed as optional prefixes.  */
        if (template->rflags & FILTRULE_NO_PREFIXES) {
                if (*s == '!' && template->rflags & FILTRULE_CVS_IGNORE)
                        rule->rflags |= FILTRULE_CLEAR_LIST; /* Tentative! */
        } else if (xflags & XFLG_OLD_PREFIXES) {
                if (*s == '-' && s[1] == ' ') {
                        rule->rflags &= ~FILTRULE_INCLUDE;
                        s += 2;
                } else if (*s == '+' && s[1] == ' ') {
                        rule->rflags |= FILTRULE_INCLUDE;
                        s += 2;
                } else if (*s == '!')
                        rule->rflags |= FILTRULE_CLEAR_LIST; /* Tentative! */
        } else {
                char ch = 0;
                BOOL prefix_specifies_side = False;
                switch (*s) {
                case 'c':
                        if ((s = RULE_STRCMP(s, "clear")) != NULL)
                                ch = '!';
                        break;
                case 'd':
                        if ((s = RULE_STRCMP(s, "dir-merge")) != NULL)
                                ch = ':';
                        break;
                case 'e':
                        if ((s = RULE_STRCMP(s, "exclude")) != NULL)
                                ch = '-';
                        break;
                case 'h':
                        if ((s = RULE_STRCMP(s, "hide")) != NULL)
                                ch = 'H';
                        break;
                case 'i':
                        if ((s = RULE_STRCMP(s, "include")) != NULL)
                                ch = '+';
                        break;
                case 'm':
                        if ((s = RULE_STRCMP(s, "merge")) != NULL)
                                ch = '.';
                        break;
                case 'p':
                        if ((s = RULE_STRCMP(s, "protect")) != NULL)
                                ch = 'P';
                        break;
                case 'r':
                        if ((s = RULE_STRCMP(s, "risk")) != NULL)
                                ch = 'R';
                        break;
                case 's':
                        if ((s = RULE_STRCMP(s, "show")) != NULL)
                                ch = 'S';
                        break;
                default:
                        ch = *s;
                        if (s[1] == ',')
                                s++;
                        break;
                }
                switch (ch) {
                case ':':
                        trust_sender_filter = 1;
                        rule->rflags |= FILTRULE_PERDIR_MERGE
                                      | FILTRULE_FINISH_SETUP;
                        /* FALL THROUGH */
                case '.':
                        rule->rflags |= FILTRULE_MERGE_FILE;
                        break;
                case '+':
                        rule->rflags |= FILTRULE_INCLUDE;
                        break;
                case '-':
                        break;
                case 'S':
                        rule->rflags |= FILTRULE_INCLUDE;
                        /* FALL THROUGH */
                case 'H':
                        rule->rflags |= FILTRULE_SENDER_SIDE;
                        prefix_specifies_side = True;
                        break;
                case 'R':
                        rule->rflags |= FILTRULE_INCLUDE;
                        /* FALL THROUGH */
                case 'P':
                        rule->rflags |= FILTRULE_RECEIVER_SIDE;
                        prefix_specifies_side = True;
                        break;
                case '!':
                        rule->rflags |= FILTRULE_CLEAR_LIST;
                        break;
                default:
                        rprintf(FERROR, "Unknown filter rule: `%s'\n", *rulestr_ptr);
                        exit_cleanup(RERR_SYNTAX);
                }
                while (ch != '!' && *++s && *s != ' ' && *s != '_') {
                        if (template->rflags & FILTRULE_WORD_SPLIT && isspace(*s)) {
                                s--;
                                break;
                        }
                        switch (*s) {
                        default:
                            invalid:
                                rprintf(FERROR,
                                        "invalid modifier '%c' at position %d in filter rule: %s\n",
                                        *s, (int)(s - (const uchar *)*rulestr_ptr), *rulestr_ptr);
                                exit_cleanup(RERR_SYNTAX);
                        case '-':
                                if (!BITS_SETnUNSET(rule->rflags, FILTRULE_MERGE_FILE, FILTRULE_NO_PREFIXES))
                                        goto invalid;
                                rule->rflags |= FILTRULE_NO_PREFIXES;
                                break;
                        case '+':
                                if (!BITS_SETnUNSET(rule->rflags, FILTRULE_MERGE_FILE, FILTRULE_NO_PREFIXES))
                                        goto invalid;
                                rule->rflags |= FILTRULE_NO_PREFIXES
                                              | FILTRULE_INCLUDE;
                                break;
                        case '/':
                                rule->rflags |= FILTRULE_ABS_PATH;
                                break;
                        case '!':
                                /* Negation really goes with the pattern, so it
                                 * isn't useful as a merge-file default. */
                                if (rule->rflags & FILTRULE_MERGE_FILE)
                                        goto invalid;
                                rule->rflags |= FILTRULE_NEGATE;
                                break;
                        case 'C':
                                if (rule->rflags & FILTRULE_NO_PREFIXES || prefix_specifies_side)
                                        goto invalid;
                                rule->rflags |= FILTRULE_NO_PREFIXES
                                              | FILTRULE_WORD_SPLIT
                                              | FILTRULE_NO_INHERIT
                                              | FILTRULE_CVS_IGNORE;
                                break;
                        case 'e':
                                if (!(rule->rflags & FILTRULE_MERGE_FILE))
                                        goto invalid;
                                rule->rflags |= FILTRULE_EXCLUDE_SELF;
                                break;
                        case 'n':
                                if (!(rule->rflags & FILTRULE_MERGE_FILE))
                                        goto invalid;
                                rule->rflags |= FILTRULE_NO_INHERIT;
                                break;
                        case 'p':
                                rule->rflags |= FILTRULE_PERISHABLE;
                                break;
                        case 'r':
                                if (prefix_specifies_side)
                                        goto invalid;
                                rule->rflags |= FILTRULE_RECEIVER_SIDE;
                                break;
                        case 's':
                                if (prefix_specifies_side)
                                        goto invalid;
                                rule->rflags |= FILTRULE_SENDER_SIDE;
                                break;
                        case 'w':
                                if (!(rule->rflags & FILTRULE_MERGE_FILE))
                                        goto invalid;
                                rule->rflags |= FILTRULE_WORD_SPLIT;
                                break;
                        case 'x':
                                rule->rflags |= FILTRULE_XATTR;
                                saw_xattr_filter = 1;
                                break;
                        }
                }
                if (*s)
                        s++;
        }
        if (template->rflags & FILTRULES_SIDES) {
                if (rule->rflags & FILTRULES_SIDES) {
                        /* The filter and template both specify side(s).  This
                         * is dodgy (and won't work correctly if the template is
                         * a one-sided per-dir merge rule), so reject it. */
                        rprintf(FERROR,
                                "specified-side merge file contains specified-side filter: %s\n",
                                *rulestr_ptr);
                        exit_cleanup(RERR_SYNTAX);
                }
                rule->rflags |= template->rflags & FILTRULES_SIDES;
        }

        if (template->rflags & FILTRULE_WORD_SPLIT) {
                const uchar *cp = s;
                /* Token ends at whitespace or the end of the string. */
                while (!isspace(*cp) && *cp != '\0')
                        cp++;
                len = cp - s;
        } else
                len = strlen((char*)s);

        if (rule->rflags & FILTRULE_CLEAR_LIST) {
                if (!(rule->rflags & FILTRULE_NO_PREFIXES)
                 && !(xflags & XFLG_OLD_PREFIXES) && len) {
                        rprintf(FERROR,
                                "'!' rule has trailing characters: %s\n", *rulestr_ptr);
                        exit_cleanup(RERR_SYNTAX);
                }
                if (len > 1)
                        rule->rflags &= ~FILTRULE_CLEAR_LIST;
        } else if (!len && !(rule->rflags & FILTRULE_CVS_IGNORE)) {
                rprintf(FERROR, "unexpected end of filter rule: %s\n", *rulestr_ptr);
                exit_cleanup(RERR_SYNTAX);
        }

        /* --delete-excluded turns an un-modified include/exclude into a sender-side rule.  */
        if (delete_excluded
         && !(rule->rflags & (FILTRULES_SIDES|FILTRULE_MERGE_FILE|FILTRULE_PERDIR_MERGE)))
                rule->rflags |= FILTRULE_SENDER_SIDE;

        *pat_ptr = (const char *)s;
        *pat_len_ptr = len;
        *rulestr_ptr = *pat_ptr + len;
        return rule;
}

static void get_cvs_excludes(uint32 rflags)
{
        static int initialized = 0;
        char *p, fname[MAXPATHLEN];

        if (initialized)
                return;
        initialized = 1;

        parse_filter_str(&cvs_filter_list, default_cvsignore(),
                         rule_template(rflags | (protocol_version >= 30 ? FILTRULE_PERISHABLE : 0)),
                         0);

        p = module_id >= 0 && lp_use_chroot(module_id) ? "/" : getenv("HOME");
        if (p && pathjoin(fname, MAXPATHLEN, p, ".cvsignore") < MAXPATHLEN)
                parse_filter_file(&cvs_filter_list, fname, rule_template(rflags), 0);

        parse_filter_str(&cvs_filter_list, getenv("CVSIGNORE"), rule_template(rflags), 0);
}

const filter_rule *rule_template(uint32 rflags)
{
        static filter_rule template; /* zero-initialized */
        template.rflags = rflags;
        return &template;
}

void parse_filter_str(filter_rule_list *listp, const char *rulestr,
                     const filter_rule *template, int xflags)
{
        filter_rule *rule;
        const char *pat;
        unsigned int pat_len;

        if (!rulestr)
                return;

        while (1) {
                uint32 new_rflags;

                /* Remember that the returned string is NOT '\0' terminated! */
                if (!(rule = parse_rule_tok(&rulestr, template, xflags, &pat, &pat_len)))
                        break;

                if (pat_len >= MAXPATHLEN) {
                        rprintf(FERROR, "discarding over-long filter: %.*s\n",
                                (int)pat_len, pat);
                    free_continue:
                        free_filter(rule);
                        continue;
                }

                new_rflags = rule->rflags;
                if (new_rflags & FILTRULE_CLEAR_LIST) {
                        if (DEBUG_GTE(FILTER, 2)) {
                                rprintf(FINFO,
                                        "[%s] clearing filter list%s\n",
                                        who_am_i(), listp->debug_type);
                        }
                        pop_filter_list(listp);
                        listp->head = NULL;
                        goto free_continue;
                }

                if (new_rflags & FILTRULE_MERGE_FILE) {
                        if (!pat_len) {
                                pat = ".cvsignore";
                                pat_len = 10;
                        }
                        if (new_rflags & FILTRULE_EXCLUDE_SELF) {
                                const char *name;
                                filter_rule *excl_self;

                                excl_self = new0(filter_rule);
                                /* Find the beginning of the basename and add an exclude for it. */
                                for (name = pat + pat_len; name > pat && name[-1] != '/'; name--) {}
                                add_rule(listp, name, (pat + pat_len) - name, excl_self, 0);
                                rule->rflags &= ~FILTRULE_EXCLUDE_SELF;
                        }
                        if (new_rflags & FILTRULE_PERDIR_MERGE) {
                                if (parent_dirscan) {
                                        const char *p;
                                        unsigned int len = pat_len;
                                        if ((p = parse_merge_name(pat, &len, module_dirlen)))
                                                add_rule(listp, p, len, rule, 0);
                                        else
                                                free_filter(rule);
                                        continue;
                                }
                        } else {
                                const char *p;
                                unsigned int len = pat_len;
                                if ((p = parse_merge_name(pat, &len, 0)))
                                        parse_filter_file(listp, p, rule, XFLG_FATAL_ERRORS);
                                free_filter(rule);
                                continue;
                        }
                }

                add_rule(listp, pat, pat_len, rule, xflags);

                if (new_rflags & FILTRULE_CVS_IGNORE
                    && !(new_rflags & FILTRULE_MERGE_FILE))
                        get_cvs_excludes(new_rflags);
        }
}

void parse_filter_file(filter_rule_list *listp, const char *fname, const filter_rule *template, int xflags)
{
        FILE *fp;
        char line[BIGPATHBUFLEN];
        char *eob = line + sizeof line - 1;
        BOOL word_split = (template->rflags & FILTRULE_WORD_SPLIT) != 0;

        if (!fname || !*fname)
                return;

        if (*fname != '-' || fname[1] || am_server) {
                if (daemon_filter_list.head) {
                        strlcpy(line, fname, sizeof line);
                        clean_fname(line, CFN_COLLAPSE_DOT_DOT_DIRS);
                        if (check_filter(&daemon_filter_list, FLOG, line, 0) < 0)
                                fp = NULL;
                        else
                                fp = fopen(line, "rb");
                } else
                        fp = fopen(fname, "rb");
        } else
                fp = stdin;

        if (DEBUG_GTE(FILTER, 2)) {
                rprintf(FINFO, "[%s] parse_filter_file(%s,%x,%x)%s\n",
                        who_am_i(), fname, template->rflags, xflags,
                        fp ? "" : " [not found]");
        }

        if (!fp) {
                if (xflags & XFLG_FATAL_ERRORS) {
                        rsyserr(FERROR, errno,
                                "failed to open %sclude file %s",
                                template->rflags & FILTRULE_INCLUDE ? "in" : "ex",
                                fname);
                        exit_cleanup(RERR_FILEIO);
                }
                return;
        }
        dirbuf[dirbuf_len] = '\0';

        while (1) {
                char *s = line;
                int ch, overflow = 0;
                while (1) {
                        if ((ch = getc(fp)) == EOF) {
                                if (ferror(fp) && errno == EINTR) {
                                        clearerr(fp);
                                        continue;
                                }
                                break;
                        }
                        if (word_split && isspace(ch))
                                break;
                        if (eol_nulls? !ch : (ch == '\n' || ch == '\r'))
                                break;
                        if (s < eob)
                                *s++ = ch;
                        else
                                overflow = 1;
                }
                if (overflow) {
                        rprintf(FERROR, "discarding over-long filter: %s...\n", line);
                        s = line;
                }
                *s = '\0';
                /* Skip an empty token and (when line parsing) comments. */
                if (*line && (word_split || (*line != ';' && *line != '#')))
                        parse_filter_str(listp, line, template, xflags);
                if (ch == EOF)
                        break;
        }
        fclose(fp);
}

/* If the "for_xfer" flag is set, the prefix is made compatible with the
 * current protocol_version (if possible) or a NULL is returned (if not
 * possible). */
char *get_rule_prefix(filter_rule *rule, const char *pat, int for_xfer,
                      unsigned int *plen_ptr)
{
        static char buf[MAX_RULE_PREFIX+1];
        char *op = buf;
        int legal_len = for_xfer && protocol_version < 29 ? 1 : MAX_RULE_PREFIX-1;

        if (rule->rflags & FILTRULE_PERDIR_MERGE) {
                if (legal_len == 1)
                        return NULL;
                *op++ = ':';
        } else if (rule->rflags & FILTRULE_INCLUDE)
                *op++ = '+';
        else if (legal_len != 1
            || ((*pat == '-' || *pat == '+') && pat[1] == ' '))
                *op++ = '-';
        else
                legal_len = 0;

        if (rule->rflags & FILTRULE_ABS_PATH)
                *op++ = '/';
        if (rule->rflags & FILTRULE_NEGATE)
                *op++ = '!';
        if (rule->rflags & FILTRULE_CVS_IGNORE)
                *op++ = 'C';
        else {
                if (rule->rflags & FILTRULE_NO_INHERIT)
                        *op++ = 'n';
                if (rule->rflags & FILTRULE_WORD_SPLIT)
                        *op++ = 'w';
                if (rule->rflags & FILTRULE_NO_PREFIXES) {
                        if (rule->rflags & FILTRULE_INCLUDE)
                                *op++ = '+';
                        else
                                *op++ = '-';
                }
        }
        if (rule->rflags & FILTRULE_EXCLUDE_SELF)
                *op++ = 'e';
        if (rule->rflags & FILTRULE_XATTR)
                *op++ = 'x';
        if (rule->rflags & FILTRULE_SENDER_SIDE
            && (!for_xfer || protocol_version >= 29))
                *op++ = 's';
        if (rule->rflags & FILTRULE_RECEIVER_SIDE
            && (!for_xfer || protocol_version >= 29
             || (delete_excluded && am_sender)))
                *op++ = 'r';
        if (rule->rflags & FILTRULE_PERISHABLE) {
                if (!for_xfer || protocol_version >= 30)
                        *op++ = 'p';
                else if (am_sender)
                        return NULL;
        }
        if (op - buf > legal_len)
                return NULL;
        if (legal_len)
                *op++ = ' ';
        *op = '\0';
        if (plen_ptr)
                *plen_ptr = op - buf;
        return buf;
}

static void send_rules(int f_out, filter_rule_list *flp)
{
        filter_rule *ent, *prev = NULL;

        for (ent = flp->head; ent; ent = ent->next) {
                unsigned int len, plen, dlen;
                int elide = 0;
                char *p;

                /* Note we need to check delete_excluded here in addition to
                 * the code in parse_rule_tok() because some rules may have
                 * been added before we found the --delete-excluded option.
                 * We must also elide any CVS merge-file rules to avoid a
                 * backward compatibility problem, and we elide any no-prefix
                 * merge files as an optimization (since they can only have
                 * include/exclude rules). */
                if (ent->rflags & FILTRULE_SENDER_SIDE)
                        elide = am_sender ? 1 : -1;
                if (ent->rflags & FILTRULE_RECEIVER_SIDE)
                        elide = elide ? 0 : am_sender ? -1 : 1;
                else if (delete_excluded && !elide
                 && (!(ent->rflags & FILTRULE_PERDIR_MERGE)
                  || ent->rflags & FILTRULE_NO_PREFIXES))
                        elide = am_sender ? 1 : -1;
                if (elide < 0) {
                        if (prev)
                                prev->next = ent->next;
                        else
                                flp->head = ent->next;
                } else
                        prev = ent;
                if (elide > 0)
                        continue;
                if (ent->rflags & FILTRULE_CVS_IGNORE
                    && !(ent->rflags & FILTRULE_MERGE_FILE)) {
                        int f = am_sender || protocol_version < 29 ? f_out : -2;
                        send_rules(f, &cvs_filter_list);
                        if (f == f_out)
                                continue;
                }
                p = get_rule_prefix(ent, ent->pattern, 1, &plen);
                if (!p) {
                        rprintf(FERROR,
                                "filter rules are too modern for remote rsync.\n");
                        exit_cleanup(RERR_PROTOCOL);
                }
                if (f_out < 0)
                        continue;
                len = strlen(ent->pattern);
                dlen = ent->rflags & FILTRULE_DIRECTORY ? 1 : 0;
                if (!(plen + len + dlen))
                        continue;
                write_int(f_out, plen + len + dlen);
                if (plen)
                        write_buf(f_out, p, plen);
                write_buf(f_out, ent->pattern, len);
                if (dlen)
                        write_byte(f_out, '/');
        }
        flp->tail = prev;
}

/* This is only called by the client. */
void send_filter_list(int f_out)
{
        int receiver_wants_list = prune_empty_dirs
            || (delete_mode && (!delete_excluded || protocol_version >= 29));

        if (local_server || (am_sender && !receiver_wants_list))
                f_out = -1;
        if (cvs_exclude && am_sender) {
                if (protocol_version >= 29)
                        parse_filter_str(&filter_list, ":C", rule_template(0), 0);
                parse_filter_str(&filter_list, "-C", rule_template(0), 0);
        }

        send_rules(f_out, &filter_list);

        if (f_out >= 0)
                write_int(f_out, 0);

        if (cvs_exclude) {
                if (!am_sender || protocol_version < 29)
                        parse_filter_str(&filter_list, ":C", rule_template(0), 0);
                if (!am_sender)
                        parse_filter_str(&filter_list, "-C", rule_template(0), 0);
        }
}

/* This is only called by the server. */
void recv_filter_list(int f_in)
{
        char line[BIGPATHBUFLEN];
        int xflags = protocol_version >= 29 ? 0 : XFLG_OLD_PREFIXES;
        int receiver_wants_list = prune_empty_dirs
            || (delete_mode && (!delete_excluded || protocol_version >= 29));
        unsigned int len;

        if (!local_server && (am_sender || receiver_wants_list)) {
                while ((len = read_int(f_in)) != 0) {
                        if (len >= sizeof line)
                                overflow_exit("recv_rules");
                        read_sbuf(f_in, line, len);
                        parse_filter_str(&filter_list, line, rule_template(0), xflags);
                }
        }

        if (cvs_exclude) {
                if (local_server || am_sender || protocol_version < 29)
                        parse_filter_str(&filter_list, ":C", rule_template(0), 0);
                if (local_server || am_sender)
                        parse_filter_str(&filter_list, "-C", rule_template(0), 0);
        }

        if (local_server) /* filter out any rules that aren't for us. */
                send_rules(-1, &filter_list);
}