/*
* SmartRoute phase 1
* connection rule patch
* by Tony Vencill (Tonto on IRC) <vencill@bga.com>
*
* The majority of this file is a recusive descent parser used to convert
* connection rules into expression trees when the conf file is read.
* All parsing structures and types are hidden in the interest of good
* programming style and to make possible future data structure changes
* without affecting the interface between this patch and the rest of the
* server. The only functions accessible externally are crule_parse,
* crule_free, and crule_eval. Prototypes for these functions can be
* found in h.h.
*
* Please direct any connection rule or SmartRoute questions to Tonto on
* IRC or by email to vencill@bga.com.
*
* For parser testing, defining CR_DEBUG generates a stand-alone parser
* that takes rules from stdin and prints out memory allocation
* information and the parsed rule. This stand alone parser is ignorant
* of the irc server and thus cannot do rule evaluation. Do not define
* this flag when compiling the server! If you wish to generate the
* test parser, compile from the ircd directory with a line similar to
* cc -o parser -DCR_DEBUG crule.c
*
* The define CR_CHKCONF is provided to generate routines needed in
* chkconf. These consist of the parser, a different crule_parse that
* prints errors to stderr, and crule_free (just for good style and to
* more closely simulate the actual ircd environment). crule_eval and
* the rule functions are made empty functions as in the stand-alone
* test parser.
*
* $Id: crule.c,v 1.6 2001/04/21 21:49:12 kev Exp $
*/
#include "config.h"
#include "crule.h"
#ifndef CR_DEBUG
/* ircd functions and types we need */
#include "client.h"
#include "ircd.h"
#include "ircd_alloc.h"
#include "ircd_chattr.h"
#include "ircd_string.h"
#include "match.h"
#include "s_bsd.h"
#include "s_debug.h"
#include "struct.h"
#include <stdio.h>
#include <stdlib.h>
#else /* includes and defines to make the stand-alone test parser */
#include <stdio.h>
#include <stdlib.h>
#define BadPtr(x) (!(x) || (*(x) == '\0'))
#define DupString(x,y) \
do { \
x = (char*) MyMalloc(strlen(y)+1); \
strcpy(x,y); \
} while(0)
/* We don't care about collation discrepacies here, it seems.... */
#define ircd_strcmp strcasecmp
#endif
#include <string.h>
#if defined(CR_DEBUG) || defined(CR_CHKCONF)
#undef MyMalloc
#undef malloc
#define MyMalloc malloc
#undef MyFree
#undef free
#define MyFree free
#endif
/* some constants and shared data types */
#define CR_MAXARGLEN 80 /* why 80? why not? it's > hostname lengths */
#define CR_MAXARGS 3 /* There's a better way to do this,
but not now. */
/*
* Some symbols for easy reading
*/
enum crule_token {
CR_UNKNOWN, CR_END, CR_AND, CR_OR, CR_NOT, CR_OPENPAREN, CR_CLOSEPAREN,
CR_COMMA, CR_WORD
};
enum crule_errcode {
CR_NOERR, CR_UNEXPCTTOK, CR_UNKNWTOK, CR_EXPCTAND, CR_EXPCTOR,
CR_EXPCTPRIM, CR_EXPCTOPEN, CR_EXPCTCLOSE, CR_UNKNWFUNC, CR_ARGMISMAT
};
/*
* Expression tree structure, function pointer, and tree pointer local!
*/
typedef int (*crule_funcptr) (int, void **);
struct CRuleNode {
crule_funcptr funcptr;
int numargs;
void *arg[CR_MAXARGS]; /* For operators arg points to a tree element;
for functions arg points to a char string. */
};
typedef struct CRuleNode* CRuleNodePtr;
/* local rule function prototypes */
static int crule_connected(int, void **);
static int crule_directcon(int, void **);
static int crule_via(int, void **);
static int crule_directop(int, void **);
static int crule__andor(int, void **);
static int crule__not(int, void **);
/* local parsing function prototypes */
static int crule_gettoken(int* token, const char** str);
static void crule_getword(char*, int*, size_t, const char**);
static int crule_parseandexpr(CRuleNodePtr*, int *, const char**);
static int crule_parseorexpr(CRuleNodePtr*, int *, const char**);
static int crule_parseprimary(CRuleNodePtr*, int *, const char**);
static int crule_parsefunction(CRuleNodePtr*, int *, const char**);
static int crule_parsearglist(CRuleNodePtr, int *, const char**);
#if defined(CR_DEBUG) || defined(CR_CHKCONF)
/*
* Prototypes for the test parser; if not debugging,
* these are defined in h.h
*/
struct CRuleNode* crule_parse(const char*);
void crule_free(struct CRuleNode**);
#ifdef CR_DEBUG
void print_tree(CRuleNodePtr);
#endif
#endif
/* error messages */
char *crule_errstr[] = {
"Unknown error", /* NOERR? - for completeness */
"Unexpected token", /* UNEXPCTTOK */
"Unknown token", /* UNKNWTOK */
"And expr expected", /* EXPCTAND */
"Or expr expected", /* EXPCTOR */
"Primary expected", /* EXPCTPRIM */
"( expected", /* EXPCTOPEN */
") expected", /* EXPCTCLOSE */
"Unknown function", /* UNKNWFUNC */
"Argument mismatch" /* ARGMISMAT */
};
/* function table - null terminated */
struct crule_funclistent {
char name[15]; /* MAXIMUM FUNCTION NAME LENGTH IS 14 CHARS!! */
int reqnumargs;
crule_funcptr funcptr;
};
struct crule_funclistent crule_funclist[] = {
/* maximum function name length is 14 chars */
{"connected", 1, crule_connected},
{"directcon", 1, crule_directcon},
{"via", 2, crule_via},
{"directop", 0, crule_directop},
{"", 0, NULL} /* this must be here to mark end of list */
};
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
static int crule_connected(int numargs, void *crulearg[])
{
struct Client *acptr;
/* taken from m_links */
for (acptr = GlobalClientList; acptr; acptr = cli_next(acptr))
{
if (!IsServer(acptr) && !IsMe(acptr))
continue;
if (match((char *)crulearg[0], cli_name(acptr)))
continue;
return (1);
}
return (0);
}
#else
static int crule_connected(int numargs, void **crulearg)
{
return (0);
}
#endif
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
static int crule_directcon(int numargs, void *crulearg[])
{
int i;
struct Client *acptr;
/* adapted from m_trace and exit_one_client */
for (i = 0; i <= HighestFd; i++)
{
if (!(acptr = LocalClientArray[i]) || !IsServer(acptr))
continue;
if (match((char *)crulearg[0], cli_name(acptr)))
continue;
return (1);
}
return (0);
}
#else
static int crule_directcon(int numargs, void **crulearg)
{
return (0);
}
#endif
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
static int crule_via(int numargs, void *crulearg[])
{
struct Client *acptr;
/* adapted from m_links */
for (acptr = GlobalClientList; acptr; acptr = cli_next(acptr))
{
if (!IsServer(acptr) && !IsMe(acptr))
continue;
if (match((char *)crulearg[1], cli_name(acptr)))
continue;
if (match((char *)crulearg[0],
cli_name(LocalClientArray[cli_fd(cli_from(acptr))])))
continue;
return (1);
}
return (0);
}
#else
static int crule_via(int numargs, void **crulearg)
{
return (0);
}
#endif
static int crule_directop(int numargs, void **crulearg)
{
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
int i;
struct Client *acptr;
/* adapted from m_trace */
for (i = 0; i <= HighestFd; i++)
{
if (!(acptr = LocalClientArray[i]) || !IsAnOper(acptr))
continue;
return (1);
}
#endif
return (0);
}
static int crule__andor(int numargs, void *crulearg[])
{
int result1;
result1 = ((CRuleNodePtr) crulearg[0])->funcptr
(((CRuleNodePtr) crulearg[0])->numargs,
((CRuleNodePtr) crulearg[0])->arg);
if (crulearg[2]) /* or */
return (result1 ||
((CRuleNodePtr) crulearg[1])->funcptr
(((CRuleNodePtr) crulearg[1])->numargs,
((CRuleNodePtr) crulearg[1])->arg));
else
return (result1 &&
((CRuleNodePtr) crulearg[1])->funcptr
(((CRuleNodePtr) crulearg[1])->numargs,
((CRuleNodePtr) crulearg[1])->arg));
}
static int crule__not(int numargs, void *crulearg[])
{
return (!((CRuleNodePtr) crulearg[0])->funcptr
(((CRuleNodePtr) crulearg[0])->numargs,
((CRuleNodePtr) crulearg[0])->arg));
}
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
int crule_eval(struct CRuleNode* rule)
{
return (rule->funcptr(rule->numargs, rule->arg));
}
#endif
static int crule_gettoken(int* next_tokp, const char** ruleptr)
{
char pending = '\0';
*next_tokp = CR_UNKNOWN;
while (*next_tokp == CR_UNKNOWN)
switch (*(*ruleptr)++)
{
case ' ':
case '\t':
break;
case '&':
if (pending == '\0')
pending = '&';
else if (pending == '&')
*next_tokp = CR_AND;
else
return (CR_UNKNWTOK);
break;
case '|':
if (pending == '\0')
pending = '|';
else if (pending == '|')
*next_tokp = CR_OR;
else
return (CR_UNKNWTOK);
break;
case '!':
*next_tokp = CR_NOT;
break;
case '(':
*next_tokp = CR_OPENPAREN;
break;
case ')':
*next_tokp = CR_CLOSEPAREN;
break;
case ',':
*next_tokp = CR_COMMA;
break;
case '\0':
(*ruleptr)--;
*next_tokp = CR_END;
break;
case ':':
*next_tokp = CR_END;
break;
default:
if ((IsAlpha(*(--(*ruleptr)))) || (**ruleptr == '*') ||
(**ruleptr == '?') || (**ruleptr == '.') || (**ruleptr == '-'))
*next_tokp = CR_WORD;
else
return (CR_UNKNWTOK);
break;
}
return CR_NOERR;
}
static void crule_getword(char* word, int* wordlenp, size_t maxlen, const char** ruleptr)
{
char *word_ptr;
word_ptr = word;
while ((size_t)(word_ptr - word) < maxlen
&& (IsAlnum(**ruleptr)
|| **ruleptr == '*' || **ruleptr == '?'
|| **ruleptr == '.' || **ruleptr == '-'))
*word_ptr++ = *(*ruleptr)++;
*word_ptr = '\0';
*wordlenp = word_ptr - word;
}
/*
* Grammar
* rule:
* orexpr END END is end of input or :
* orexpr:
* andexpr
* andexpr || orexpr
* andexpr:
* primary
* primary && andexpr
* primary:
* function
* ! primary
* ( orexpr )
* function:
* word ( ) word is alphanumeric string, first character
* word ( arglist ) must be a letter
* arglist:
* word
* word , arglist
*/
struct CRuleNode* crule_parse(const char *rule)
{
const char* ruleptr = rule;
int next_tok;
struct CRuleNode* ruleroot = 0;
int errcode = CR_NOERR;
if ((errcode = crule_gettoken(&next_tok, &ruleptr)) == CR_NOERR) {
if ((errcode = crule_parseorexpr(&ruleroot, &next_tok, &ruleptr)) == CR_NOERR) {
if (ruleroot != NULL) {
if (next_tok == CR_END)
return (ruleroot);
else
errcode = CR_UNEXPCTTOK;
}
else
errcode = CR_EXPCTOR;
}
}
if (ruleroot != NULL)
crule_free(&ruleroot);
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
Debug((DEBUG_ERROR, "%s in rule: %s", crule_errstr[errcode], rule));
#else
fprintf(stderr, "%s in rule: %s\n", crule_errstr[errcode], rule);
#endif
return 0;
}
static int crule_parseorexpr(CRuleNodePtr * orrootp, int *next_tokp, const char** ruleptr)
{
int errcode = CR_NOERR;
CRuleNodePtr andexpr;
CRuleNodePtr orptr;
*orrootp = NULL;
while (errcode == CR_NOERR)
{
errcode = crule_parseandexpr(&andexpr, next_tokp, ruleptr);
if ((errcode == CR_NOERR) && (*next_tokp == CR_OR))
{
orptr = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
#ifdef CR_DEBUG
fprintf(stderr, "allocating or element at %ld\n", orptr);
#endif
orptr->funcptr = crule__andor;
orptr->numargs = 3;
orptr->arg[2] = (void *)1;
if (*orrootp != NULL)
{
(*orrootp)->arg[1] = andexpr;
orptr->arg[0] = *orrootp;
}
else
orptr->arg[0] = andexpr;
*orrootp = orptr;
}
else
{
if (*orrootp != NULL)
{
if (andexpr != NULL)
{
(*orrootp)->arg[1] = andexpr;
return (errcode);
}
else
{
(*orrootp)->arg[1] = NULL; /* so free doesn't seg fault */
return (CR_EXPCTAND);
}
}
else
{
*orrootp = andexpr;
return (errcode);
}
}
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
}
return (errcode);
}
static int crule_parseandexpr(CRuleNodePtr * androotp, int *next_tokp, const char** ruleptr)
{
int errcode = CR_NOERR;
CRuleNodePtr primary;
CRuleNodePtr andptr;
*androotp = NULL;
while (errcode == CR_NOERR)
{
errcode = crule_parseprimary(&primary, next_tokp, ruleptr);
if ((errcode == CR_NOERR) && (*next_tokp == CR_AND))
{
andptr = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
#ifdef CR_DEBUG
fprintf(stderr, "allocating and element at %ld\n", andptr);
#endif
andptr->funcptr = crule__andor;
andptr->numargs = 3;
andptr->arg[2] = (void *)0;
if (*androotp != NULL)
{
(*androotp)->arg[1] = primary;
andptr->arg[0] = *androotp;
}
else
andptr->arg[0] = primary;
*androotp = andptr;
}
else
{
if (*androotp != NULL)
{
if (primary != NULL)
{
(*androotp)->arg[1] = primary;
return (errcode);
}
else
{
(*androotp)->arg[1] = NULL; /* so free doesn't seg fault */
return (CR_EXPCTPRIM);
}
}
else
{
*androotp = primary;
return (errcode);
}
}
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
}
return (errcode);
}
static int crule_parseprimary(CRuleNodePtr* primrootp, int *next_tokp, const char** ruleptr)
{
CRuleNodePtr *insertionp;
int errcode = CR_NOERR;
*primrootp = NULL;
insertionp = primrootp;
while (errcode == CR_NOERR)
{
switch (*next_tokp)
{
case CR_OPENPAREN:
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
break;
if ((errcode = crule_parseorexpr(insertionp, next_tokp, ruleptr)) != CR_NOERR)
break;
if (*insertionp == NULL)
{
errcode = CR_EXPCTAND;
break;
}
if (*next_tokp != CR_CLOSEPAREN)
{
errcode = CR_EXPCTCLOSE;
break;
}
errcode = crule_gettoken(next_tokp, ruleptr);
break;
case CR_NOT:
*insertionp = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
#ifdef CR_DEBUG
fprintf(stderr, "allocating primary element at %ld\n", *insertionp);
#endif
(*insertionp)->funcptr = crule__not;
(*insertionp)->numargs = 1;
(*insertionp)->arg[0] = NULL;
insertionp = (CRuleNodePtr *) & ((*insertionp)->arg[0]);
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
break;
continue;
case CR_WORD:
errcode = crule_parsefunction(insertionp, next_tokp, ruleptr);
break;
default:
if (*primrootp == NULL)
errcode = CR_NOERR;
else
errcode = CR_EXPCTPRIM;
break;
}
return (errcode);
}
return (errcode);
}
static int crule_parsefunction(CRuleNodePtr* funcrootp, int* next_tokp, const char** ruleptr)
{
int errcode = CR_NOERR;
char funcname[CR_MAXARGLEN];
int namelen;
int funcnum;
*funcrootp = NULL;
crule_getword(funcname, &namelen, CR_MAXARGLEN - 1, ruleptr);
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
if (*next_tokp == CR_OPENPAREN)
{
for (funcnum = 0;; funcnum++)
{
if (0 == ircd_strcmp(crule_funclist[funcnum].name, funcname))
break;
if (crule_funclist[funcnum].name[0] == '\0')
return (CR_UNKNWFUNC);
}
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
*funcrootp = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
#ifdef CR_DEBUG
fprintf(stderr, "allocating function element at %ld\n", *funcrootp);
#endif
(*funcrootp)->funcptr = NULL; /* for freeing aborted trees */
if ((errcode =
crule_parsearglist(*funcrootp, next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
if (*next_tokp != CR_CLOSEPAREN)
return (CR_EXPCTCLOSE);
if ((crule_funclist[funcnum].reqnumargs != (*funcrootp)->numargs) &&
(crule_funclist[funcnum].reqnumargs != -1))
return (CR_ARGMISMAT);
if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
return (errcode);
(*funcrootp)->funcptr = crule_funclist[funcnum].funcptr;
return (CR_NOERR);
}
else
return (CR_EXPCTOPEN);
}
static int crule_parsearglist(CRuleNodePtr argrootp, int *next_tokp, const char** ruleptr)
{
int errcode = CR_NOERR;
char *argelemp = NULL;
char currarg[CR_MAXARGLEN];
int arglen = 0;
char word[CR_MAXARGLEN];
int wordlen = 0;
argrootp->numargs = 0;
currarg[0] = '\0';
while (errcode == CR_NOERR)
{
switch (*next_tokp)
{
case CR_WORD:
crule_getword(word, &wordlen, CR_MAXARGLEN - 1, ruleptr);
if (currarg[0] != '\0')
{
if ((arglen + wordlen) < (CR_MAXARGLEN - 1))
{
strcat(currarg, " ");
strcat(currarg, word);
arglen += wordlen + 1;
}
}
else
{
strcpy(currarg, word);
arglen = wordlen;
}
errcode = crule_gettoken(next_tokp, ruleptr);
break;
default:
#if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
collapse(currarg);
#endif
if (!BadPtr(currarg))
{
DupString(argelemp, currarg);
argrootp->arg[argrootp->numargs++] = (void *)argelemp;
}
if (*next_tokp != CR_COMMA)
return (CR_NOERR);
currarg[0] = '\0';
errcode = crule_gettoken(next_tokp, ruleptr);
break;
}
}
return (errcode);
}
/*
* This function is recursive.. I wish I knew a nonrecursive way but
* I dont. anyway, recursion is fun.. :)
* DO NOT CALL THIS FUNTION WITH A POINTER TO A NULL POINTER
* (ie: If *elem is NULL, you're doing it wrong - seg fault)
*/
void crule_free(struct CRuleNode** elem)
{
int arg, numargs;
if ((*(elem))->funcptr == crule__not)
{
/* type conversions and ()'s are fun! ;) here have an asprin.. */
if ((*(elem))->arg[0] != NULL)
crule_free((struct CRuleNode**) &((*(elem))->arg[0]));
}
else if ((*(elem))->funcptr == crule__andor)
{
crule_free((struct CRuleNode**) &((*(elem))->arg[0]));
if ((*(elem))->arg[1] != NULL)
crule_free((struct CRuleNode**) &((*(elem))->arg[1]));
}
else
{
numargs = (*(elem))->numargs;
for (arg = 0; arg < numargs; arg++)
MyFree((*(elem))->arg[arg]);
}
#ifdef CR_DEBUG
fprintf(stderr, "freeing element at %ld\n", *elem);
#endif
MyFree(*elem);
*elem = 0;
}
#ifdef CR_DEBUG
static void print_tree(CRuleNodePtr printelem)
{
int funcnum, arg;
if (printelem->funcptr == crule__not)
{
printf("!( ");
print_tree((CRuleNodePtr) printelem->arg[0]);
printf(") ");
}
else if (printelem->funcptr == crule__andor)
{
printf("( ");
print_tree((CRuleNodePtr) printelem->arg[0]);
if (printelem->arg[2])
printf("|| ");
else
printf("&& ");
print_tree((CRuleNodePtr) printelem->arg[1]);
printf(") ");
}
else
{
for (funcnum = 0;; funcnum++)
{
if (printelem->funcptr == crule_funclist[funcnum].funcptr)
break;
if (crule_funclist[funcnum].funcptr == NULL)
MyCoreDump;
}
printf("%s(", crule_funclist[funcnum].name);
for (arg = 0; arg < printelem->numargs; arg++)
{
if (arg != 0)
printf(",");
printf("%s", (char *)printelem->arg[arg]);
}
printf(") ");
}
}
#endif
#ifdef CR_DEBUG
int main(void)
{
char indata[256];
CRuleNode* rule;
printf("rule: ");
while (fgets(indata, 256, stdin) != NULL)
{
indata[strlen(indata) - 1] = '\0'; /* lose the newline */
if ((rule = crule_parse(indata)) != NULL)
{
printf("equivalent rule: ");
print_tree((CRuleNodePtr) rule);
printf("\n");
crule_free(&rule);
}
printf("\nrule: ");
}
printf("\n");
return 0;
}
#endif
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