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allow to set max passes per rule

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Pierangelo Masarati 2003-12-29 18:02:49 +00:00
parent 9e86d9ffe2
commit 3994dc645a
5 changed files with 79 additions and 12 deletions
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30
doc/man/man5/slapd-meta.5
View file

@ -332,8 +332,8 @@ server will possibly enforce additional restrictions to "foo".
A string is rewritten according to a set of rules, called a `rewrite
context'.
The rules are based on Regular Expressions (POSIX regex) with
substring matching; extensions are planned to allow basic variable
substitution and map resolution of substrings.
substring matching; basic variable substitution and map resolution
of substrings is allowed by specific mechanisms detailed in the following.
The behavior of pattern matching/substitution can be altered by a set
of flags.
.LP
@ -341,14 +341,17 @@ The underlying concept is to build a lightweight rewrite module
for the slapd server (initially dedicated to the LDAP backend).
.SH Passes
An incoming string is matched agains a set of rules.
Rules are made of a match pattern, a substitution pattern and a set of
actions.
Rules are made of a regex match pattern, a substitution pattern
and a set of actions, described by a set of flags.
In case of match a string rewriting is performed according to the
substitution pattern that allows to refer to substrings matched in the
incoming string.
The actions, if any, are finally performed.
The substitution pattern allows map resolution of substrings.
A map is a generic object that maps a substitution pattern to a value.
The flags are divided in "Pattern matching Flags" and "Action Flags";
the former alter the regex match pattern behaviorm while the latter
alter the action that is taken after substitution.
.SH "Pattern Matching Flags"
.TP
.B `C'
@ -356,6 +359,12 @@ honors case in matching (default is case insensitive)
.TP
.B `R'
use POSIX Basic Regular Expressions (default is Extended)
.TP
.B `M{n}'
allow no more than
.B n
recursive passes for a specific rule; does not alter the max total count
of passes, so it can only enforce a stricter limit for a specific rule.
.SH "Action Flags"
.TP
.B `:'
@ -398,7 +407,7 @@ or, in other words, `@' is equivalent to `U{0}'.
By convention, the freely available codes are above 16 included;
the others are reserved.
.LP
The ordering of the flags is significant.
The ordering of the flags can be significant.
For instance: `IG{2}' means ignore errors and jump two lines ahead
both in case of match and in case of error, while `G{2}I' means ignore
errors, but jump two lines ahead only in case of match.
@ -549,7 +558,7 @@ In this case the alias context contains no rule, and any reference to
it will result in accessing the aliased one.
.TP
.B rewriteRule "<regex match pattern>" "<substitution pattern>" "[ <flags> ]"
Determines how a tring can be rewritten if a pattern is matched.
Determines how a string can be rewritten if a pattern is matched.
Examples are reported below.
.SH "Additional configuration syntax:"
.TP
@ -562,9 +571,16 @@ The map is referenced inside the substitution pattern of a rule.
Sets a value with global scope, that can be dereferenced by the
command `%{$paramName}'.
.TP
.B rewriteMaxPasses <number of passes>
.B rewriteMaxPasses <number of passes> [<number of passes per rule>]
Sets the maximum number of total rewriting passes that can be
performed in a single rewrite operation (to avoid loops).
A safe default is set to 100; note that reaching this limit is still
treated as a success; recursive invocation of rules is simply
interrupted.
The count applies to the rewriting operation as a whole, not
to any single rule; an optional per-rule limit can be set.
This limit is overridden by setting specific per-rule limits
with the `M{n}' flag.
.SH "Configuration examples:"
.nf
# set to `off' to disable rewriting

20
libraries/librewrite/config.c
View file

@ -39,7 +39,7 @@ rewrite_parse_builtin_map(
* lines handled are of the form:
*
* rewriteEngine {on|off}
* rewriteMaxPasses numPasses
* rewriteMaxPasses numPasses [numPassesPerRule]
* rewriteContext contextName [alias aliasedContextName]
* rewriteRule pattern substPattern [ruleFlags]
* rewriteMap mapType mapName [mapArgs]
@ -103,7 +103,25 @@ rewrite_parse(
fname, lineno, "" );
return -1;
}
info->li_max_passes = atoi( argv[ 1 ] );
if ( info->li_max_passes <= 0 ) {
Debug( LDAP_DEBUG_ANY,
"[%s:%d] negative or null rewriteMaxPasses'\n",
fname, lineno, 0 );
}
if ( argc > 2 ) {
info->li_max_passes_per_rule = atoi( argv[ 2 ] );
if ( info->li_max_passes_per_rule <= 0 ) {
Debug( LDAP_DEBUG_ANY,
"[%s:%d] negative or null rewriteMaxPassesPerRule'\n",
fname, lineno, 0 );
}
} else {
info->li_max_passes_per_rule = info->li_max_passes;
}
rc = REWRITE_SUCCESS;
/*

1
libraries/librewrite/info.c
View file

@ -67,6 +67,7 @@ rewrite_info_init(
info->li_state = REWRITE_DEFAULT;
info->li_max_passes = REWRITE_MAX_PASSES;
info->li_max_passes_per_rule = REWRITE_MAX_PASSES;
info->li_rewrite_mode = mode;
/*

3
libraries/librewrite/rewrite-int.h
View file

@ -72,6 +72,7 @@
#define REWRITE_FLAG_UNWILLING '#'
#define REWRITE_FLAG_GOTO 'G' /* requires an arg */
#define REWRITE_FLAG_USER 'U' /* requires an arg */
#define REWRITE_FLAG_MAX_PASSES 'M' /* requires an arg */
#define REWRITE_FLAG_IGNORE_ERR 'I'
/*
@ -219,6 +220,7 @@ struct rewrite_rule {
#define REWRITE_RECURSE 0x0001
#define REWRITE_EXEC_ONCE 0x0002
int lr_mode;
int lr_max_passes;
struct rewrite_action *lr_action;
};
@ -304,6 +306,7 @@ struct rewrite_info {
*/
#define REWRITE_MAXPASSES 100
int li_max_passes;
int li_max_passes_per_rule;
/*
* Behavior in case a NULL or non-existent context is required

37
libraries/librewrite/rule.c
View file

@ -116,6 +116,7 @@ rewrite_rule_compile(
{
int flags = REWRITE_REGEX_EXTENDED | REWRITE_REGEX_ICASE;
int mode = REWRITE_RECURSE;
int max_passes = info->li_max_passes_per_rule;
struct rewrite_rule *rule = NULL;
struct rewrite_subst *subst = NULL;
@ -264,6 +265,33 @@ rewrite_rule_compile(
break;
}
case REWRITE_FLAG_MAX_PASSES: { /* 'U' */
/*
* Set the number of max passes per rule
*/
char *next = NULL;
if ( p[ 1 ] != '{' ) {
/* XXX Need to free stuff */
return REWRITE_ERR;
}
max_passes = strtol( &p[ 2 ], &next, 0 );
if ( next == NULL || next == &p[ 2 ] || next[0] != '}' ) {
/* XXX Need to free stuff */
return REWRITE_ERR;
}
if ( max_passes < 1 ) {
/* FIXME: nonsense ... */
max_passes = 1;
}
p = next; /* p is incremented by the for ... */
break;
}
case REWRITE_FLAG_IGNORE_ERR: /* 'I' */
/*
* Ignore errors!
@ -337,6 +365,7 @@ rewrite_rule_compile(
*/
rule->lr_flags = flags; /* don't really need any longer ... */
rule->lr_mode = mode;
rule->lr_max_passes = max_passes;
rule->lr_action = first_action;
/*
@ -387,8 +416,8 @@ rewrite_rule_apply(
recurse:;
Debug( LDAP_DEBUG_TRACE, "==> rewrite_rule_apply"
" rule='%s' string='%s'\n",
rule->lr_pattern, string, 0 );
" rule='%s' string='%s' [%s pass(es)]\n",
rule->lr_pattern, string, strcnt + 1 );
op->lo_num_passes++;
if ( regexec( &rule->lr_regex, string, nmatch, match, 0 ) != 0 ) {
@ -418,9 +447,9 @@ recurse:;
}
if ( ( rule->lr_mode & REWRITE_RECURSE ) == REWRITE_RECURSE
&& op->lo_num_passes <= info->li_max_passes ) {
&& op->lo_num_passes < info->li_max_passes
&& ++strcnt < rule->lr_max_passes ) {
string = *result;
strcnt++;
goto recurse;
}