bird/conf/cf-lex.l
Ondrej Zajicek (work) b7761af34d Conf: Replace keyword and symbol hash table with generic hash table.
The old hash table had fixed size, which makes it slow for config files
with large number of symbols and symbol lookups. The new one is growing
according to needs.
2017-05-25 23:30:39 +02:00

697 lines
16 KiB
Text

/*
* BIRD -- Configuration Lexer
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Lexical analyzer
*
* The lexical analyzer used for configuration files and CLI commands
* is generated using the |flex| tool accompanied by a couple of
* functions maintaining the hash tables containing information about
* symbols and keywords.
*
* Each symbol is represented by a &symbol structure containing name
* of the symbol, its lexical scope, symbol class (%SYM_PROTO for a
* name of a protocol, %SYM_CONSTANT for a constant etc.) and class
* dependent data. When an unknown symbol is encountered, it's
* automatically added to the symbol table with class %SYM_VOID.
*
* The keyword tables are generated from the grammar templates
* using the |gen_keywords.m4| script.
*/
%{
#undef REJECT /* Avoid name clashes */
#include <errno.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <unistd.h>
#include <libgen.h>
#include <glob.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/stat.h>
#define PARSER 1
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "filter/filter.h"
#include "conf/conf.h"
#include "conf/cf-parse.tab.h"
#include "lib/string.h"
#include "lib/hash.h"
struct keyword {
byte *name;
int value;
struct keyword *next;
};
#include "conf/keywords.h"
static uint cf_hash(byte *c);
#define KW_KEY(n) n->name
#define KW_NEXT(n) n->next
#define KW_EQ(a,b) !strcmp(a,b)
#define KW_FN(k) cf_hash(k)
#define KW_ORDER 8 /* Fixed */
#define SYM_KEY(n) n->name, n->scope->active
#define SYM_NEXT(n) n->next
#define SYM_EQ(a,s1,b,s2) !strcmp(a,b) && s1 == s2
#define SYM_FN(k,s) cf_hash(k)
#define SYM_ORDER 6 /* Initial */
#define SYM_REHASH sym_rehash
#define SYM_PARAMS /8, *1, 2, 2, 6, 20
HASH_DEFINE_REHASH_FN(SYM, struct symbol)
HASH(struct keyword) kw_hash;
static struct sym_scope *conf_this_scope;
linpool *cfg_mem;
int (*cf_read_hook)(byte *buf, unsigned int max, int fd);
struct include_file_stack *ifs;
static struct include_file_stack *ifs_head;
#define MAX_INCLUDE_DEPTH 8
#define YY_INPUT(buf,result,max) result = cf_read_hook(buf, max, ifs->fd);
#define YY_NO_UNPUT
#define YY_FATAL_ERROR(msg) cf_error(msg)
static void cf_include(char *arg, int alen);
static int check_eof(void);
%}
%option noyywrap
%option noinput
%option nounput
%option noreject
%x COMMENT CCOMM CLI
ALPHA [a-zA-Z_]
DIGIT [0-9]
XIGIT [0-9a-fA-F]
ALNUM [a-zA-Z_0-9]
WHITE [ \t]
include ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
%%
{include} {
char *start, *end;
if (!ifs->depth)
cf_error("Include not allowed in CLI");
start = strchr(yytext, '"');
start++;
end = strchr(start, '"');
*end = 0;
if (start == end)
cf_error("Include with empty argument");
cf_include(start, end-start);
}
{DIGIT}+\.{DIGIT}+\.{DIGIT}+\.{DIGIT}+ {
ip4_addr a;
if (!ip4_pton(yytext, &a))
cf_error("Invalid IPv4 address %s", yytext);
#ifdef IPV6
cf_lval.i32 = ip4_to_u32(a);
return RTRID;
#else
cf_lval.a = ipa_from_ip4(a);
return IPA;
#endif
}
({XIGIT}*::|({XIGIT}*:){3,})({XIGIT}*|{DIGIT}+\.{DIGIT}+\.{DIGIT}+\.{DIGIT}+) {
#ifdef IPV6
if (ipa_pton(yytext, &cf_lval.a))
return IPA;
cf_error("Invalid IPv6 address %s", yytext);
#else
cf_error("This is an IPv4 router, therefore IPv6 addresses are not supported");
#endif
}
0x{XIGIT}+ {
char *e;
unsigned long int l;
errno = 0;
l = strtoul(yytext+2, &e, 16);
if (e && *e || errno == ERANGE || (unsigned long int)(unsigned int) l != l)
cf_error("Number out of range");
cf_lval.i = l;
return NUM;
}
{DIGIT}+ {
char *e;
unsigned long int l;
errno = 0;
l = strtoul(yytext, &e, 10);
if (e && *e || errno == ERANGE || (unsigned long int)(unsigned int) l != l)
cf_error("Number out of range");
cf_lval.i = l;
return NUM;
}
else: {
/* Hack to distinguish if..else from else: in case */
return ELSECOL;
}
({ALPHA}{ALNUM}*|[']({ALNUM}|[-]|[\.]|[:])*[']) {
if(*yytext == '\'') {
yytext[yyleng-1] = 0;
yytext++;
}
struct keyword *k = HASH_FIND(kw_hash, KW, yytext);
if (k)
{
if (k->value > 0)
return k->value;
else
{
cf_lval.i = -k->value;
return ENUM;
}
}
cf_lval.s = cf_get_symbol(yytext);
return SYM;
}
<CLI>(.|\n) {
BEGIN(INITIAL);
return CLI_MARKER;
}
\.\. {
return DDOT;
}
[={}:;,.()+*/%<>~\[\]?!\|-] {
return yytext[0];
}
["][^"\n]*["] {
yytext[yyleng-1] = 0;
cf_lval.t = cfg_strdup(yytext+1);
return TEXT;
}
["][^"\n]*\n cf_error("Unterminated string");
<INITIAL,COMMENT><<EOF>> { if (check_eof()) return END; }
{WHITE}+
\n ifs->lino++;
# BEGIN(COMMENT);
\/\* BEGIN(CCOMM);
. cf_error("Unknown character");
<COMMENT>\n {
ifs->lino++;
BEGIN(INITIAL);
}
<COMMENT>.
<CCOMM>\*\/ BEGIN(INITIAL);
<CCOMM>\n ifs->lino++;
<CCOMM>\/\* cf_error("Comment nesting not supported");
<CCOMM><<EOF>> cf_error("Unterminated comment");
<CCOMM>.
\!\= return NEQ;
\!\~ return NMA;
\<\= return LEQ;
\>\= return GEQ;
\&\& return AND;
\|\| return OR;
\[\= return PO;
\=\] return PC;
%%
static uint
cf_hash(byte *c)
{
uint h = 13 << 24;
while (*c)
h = h + (h >> 2) + (h >> 5) + ((uint) *c++ << 24);
return h;
}
/*
* IFS stack - it contains structures needed for recursive processing
* of include in config files. On the top of the stack is a structure
* for currently processed file. Other structures are either for
* active files interrupted because of include directive (these have
* fd and flex buffer) or for inactive files scheduled to be processed
* later (when parent requested including of several files by wildcard
* match - these do not have fd and flex buffer yet).
*
* FIXME: Most of these ifs and include functions are really sysdep/unix.
*/
static struct include_file_stack *
push_ifs(struct include_file_stack *old)
{
struct include_file_stack *ret;
ret = cfg_allocz(sizeof(struct include_file_stack));
ret->lino = 1;
ret->prev = old;
return ret;
}
static struct include_file_stack *
pop_ifs(struct include_file_stack *old)
{
yy_delete_buffer(old->buffer);
close(old->fd);
return old->prev;
}
static void
enter_ifs(struct include_file_stack *new)
{
if (!new->buffer)
{
new->fd = open(new->file_name, O_RDONLY);
if (new->fd < 0)
{
ifs = ifs->up;
cf_error("Unable to open included file %s: %m", new->file_name);
}
new->buffer = yy_create_buffer(NULL, YY_BUF_SIZE);
}
yy_switch_to_buffer(new->buffer);
}
/**
* cf_lex_unwind - unwind lexer state during error
*
* cf_lex_unwind() frees the internal state on IFS stack when the lexical
* analyzer is terminated by cf_error().
*/
void
cf_lex_unwind(void)
{
struct include_file_stack *n;
for (n = ifs; n != ifs_head; n = n->prev)
{
/* Memory is freed automatically */
if (n->buffer)
yy_delete_buffer(n->buffer);
if (n->fd)
close(n->fd);
}
ifs = ifs_head;
}
static void
cf_include(char *arg, int alen)
{
struct include_file_stack *base_ifs = ifs;
int new_depth, rv, i;
char *patt;
glob_t g = {};
new_depth = ifs->depth + 1;
if (new_depth > MAX_INCLUDE_DEPTH)
cf_error("Max include depth reached");
/* expand arg to properly handle relative filenames */
if (*arg != '/')
{
int dlen = strlen(ifs->file_name);
char *dir = alloca(dlen + 1);
patt = alloca(dlen + alen + 2);
memcpy(dir, ifs->file_name, dlen + 1);
sprintf(patt, "%s/%s", dirname(dir), arg);
}
else
patt = arg;
/* Skip globbing if there are no wildcards, mainly to get proper
response when the included config file is missing */
if (!strpbrk(arg, "?*["))
{
ifs = push_ifs(ifs);
ifs->file_name = cfg_strdup(patt);
ifs->depth = new_depth;
ifs->up = base_ifs;
enter_ifs(ifs);
return;
}
/* Expand the pattern */
rv = glob(patt, GLOB_ERR | GLOB_NOESCAPE, NULL, &g);
if (rv == GLOB_ABORTED)
cf_error("Unable to match pattern %s: %m", patt);
if ((rv != 0) || (g.gl_pathc <= 0))
return;
/*
* Now we put all found files to ifs stack in reverse order, they
* will be activated and processed in order as ifs stack is popped
* by pop_ifs() and enter_ifs() in check_eof().
*/
for(i = g.gl_pathc - 1; i >= 0; i--)
{
char *fname = g.gl_pathv[i];
struct stat fs;
if (stat(fname, &fs) < 0)
{
globfree(&g);
cf_error("Unable to stat included file %s: %m", fname);
}
if (fs.st_mode & S_IFDIR)
continue;
/* Prepare new stack item */
ifs = push_ifs(ifs);
ifs->file_name = cfg_strdup(fname);
ifs->depth = new_depth;
ifs->up = base_ifs;
}
globfree(&g);
enter_ifs(ifs);
}
static int
check_eof(void)
{
if (ifs == ifs_head)
{
/* EOF in main config file */
ifs->lino = 1; /* Why this? */
return 1;
}
ifs = pop_ifs(ifs);
enter_ifs(ifs);
return 0;
}
static struct symbol *
cf_new_symbol(byte *c)
{
struct symbol *s;
uint l = strlen(c);
if (l > SYM_MAX_LEN)
cf_error("Symbol too long");
s = cfg_alloc(sizeof(struct symbol) + l);
s->scope = conf_this_scope;
s->class = SYM_VOID;
s->def = NULL;
s->aux = 0;
strcpy(s->name, c);
if (!new_config->sym_hash.data)
HASH_INIT(new_config->sym_hash, new_config->pool, SYM_ORDER);
HASH_INSERT2(new_config->sym_hash, SYM, new_config->pool, s);
return s;
}
/**
* cf_find_symbol - find a symbol by name
* @cfg: specificed config
* @c: symbol name
*
* This functions searches the symbol table in the config @cfg for a symbol of
* given name. First it examines the current scope, then the second recent one
* and so on until it either finds the symbol and returns a pointer to its
* &symbol structure or reaches the end of the scope chain and returns %NULL to
* signify no match.
*/
struct symbol *
cf_find_symbol(struct config *cfg, byte *c)
{
struct symbol *s;
if (cfg->sym_hash.data &&
(s = HASH_FIND(cfg->sym_hash, SYM, c, 1)))
return s;
if (cfg->fallback &&
cfg->fallback->sym_hash.data &&
(s = HASH_FIND(cfg->fallback->sym_hash, SYM, c, 1)))
return s;
return NULL;
}
/**
* cf_get_symbol - get a symbol by name
* @c: symbol name
*
* This functions searches the symbol table of the currently parsed config
* (@new_config) for a symbol of given name. It returns either the already
* existing symbol or a newly allocated undefined (%SYM_VOID) symbol if no
* existing symbol is found.
*/
struct symbol *
cf_get_symbol(byte *c)
{
return cf_find_symbol(new_config, c) ?: cf_new_symbol(c);
}
struct symbol *
cf_default_name(char *template, int *counter)
{
char buf[SYM_MAX_LEN];
struct symbol *s;
char *perc = strchr(template, '%');
for(;;)
{
bsprintf(buf, template, ++(*counter));
s = cf_get_symbol(buf);
if (s->class == SYM_VOID)
return s;
if (!perc)
break;
}
cf_error("Unable to generate default name");
}
/**
* cf_define_symbol - define meaning of a symbol
* @sym: symbol to be defined
* @type: symbol class to assign
* @def: class dependent data
*
* Defines new meaning of a symbol. If the symbol is an undefined
* one (%SYM_VOID), it's just re-defined to the new type. If it's defined
* in different scope, a new symbol in current scope is created and the
* meaning is assigned to it. If it's already defined in the current scope,
* an error is reported via cf_error().
*
* Result: Pointer to the newly defined symbol. If we are in the top-level
* scope, it's the same @sym as passed to the function.
*/
struct symbol *
cf_define_symbol(struct symbol *sym, int type, void *def)
{
if (sym->class)
{
if (sym->scope == conf_this_scope)
cf_error("Symbol already defined");
sym = cf_new_symbol(sym->name);
}
sym->class = type;
sym->def = def;
return sym;
}
static void
cf_lex_init_kh(void)
{
HASH_INIT(kw_hash, &root_pool, KW_ORDER);
struct keyword *k;
for (k=keyword_list; k->name; k++)
HASH_INSERT(kw_hash, KW, k);
}
/**
* cf_lex_init - initialize the lexer
* @is_cli: true if we're going to parse CLI command, false for configuration
* @c: configuration structure
*
* cf_lex_init() initializes the lexical analyzer and prepares it for
* parsing of a new input.
*/
void
cf_lex_init(int is_cli, struct config *c)
{
if (!kw_hash.data)
cf_lex_init_kh();
ifs_head = ifs = push_ifs(NULL);
if (!is_cli)
{
ifs->file_name = c->file_name;
ifs->fd = c->file_fd;
ifs->depth = 1;
}
yyrestart(NULL);
ifs->buffer = YY_CURRENT_BUFFER;
if (is_cli)
BEGIN(CLI);
else
BEGIN(INITIAL);
conf_this_scope = cfg_allocz(sizeof(struct sym_scope));
conf_this_scope->active = 1;
}
/**
* cf_push_scope - enter new scope
* @sym: symbol representing scope name
*
* If we want to enter a new scope to process declarations inside
* a nested block, we can just call cf_push_scope() to push a new
* scope onto the scope stack which will cause all new symbols to be
* defined in this scope and all existing symbols to be sought for
* in all scopes stored on the stack.
*/
void
cf_push_scope(struct symbol *sym)
{
struct sym_scope *s = cfg_alloc(sizeof(struct sym_scope));
s->next = conf_this_scope;
conf_this_scope = s;
s->active = 1;
s->name = sym;
}
/**
* cf_pop_scope - leave a scope
*
* cf_pop_scope() pops the topmost scope from the scope stack,
* leaving all its symbols in the symbol table, but making them
* invisible to the rest of the config.
*/
void
cf_pop_scope(void)
{
conf_this_scope->active = 0;
conf_this_scope = conf_this_scope->next;
ASSERT(conf_this_scope);
}
/**
* cf_symbol_class_name - get name of a symbol class
* @sym: symbol
*
* This function returns a string representing the class
* of the given symbol.
*/
char *
cf_symbol_class_name(struct symbol *sym)
{
if (cf_symbol_is_constant(sym))
return "constant";
switch (sym->class)
{
case SYM_VOID:
return "undefined";
case SYM_PROTO:
return "protocol";
case SYM_TEMPLATE:
return "protocol template";
case SYM_FUNCTION:
return "function";
case SYM_FILTER:
return "filter";
case SYM_TABLE:
return "routing table";
case SYM_ROA:
return "ROA table";
default:
return "unknown type";
}
}
/**
* DOC: Parser
*
* Both the configuration and CLI commands are analyzed using a syntax
* driven parser generated by the |bison| tool from a grammar which
* is constructed from information gathered from grammar snippets by
* the |gen_parser.m4| script.
*
* Grammar snippets are files (usually with extension |.Y|) contributed
* by various BIRD modules in order to provide information about syntax of their
* configuration and their CLI commands. Each snipped consists of several
* sections, each of them starting with a special keyword: |CF_HDR| for
* a list of |#include| directives needed by the C code, |CF_DEFINES|
* for a list of C declarations, |CF_DECLS| for |bison| declarations
* including keyword definitions specified as |CF_KEYWORDS|, |CF_GRAMMAR|
* for the grammar rules, |CF_CODE| for auxiliary C code and finally
* |CF_END| at the end of the snippet.
*
* To create references between the snippets, it's possible to define
* multi-part rules by utilizing the |CF_ADDTO| macro which adds a new
* alternative to a multi-part rule.
*
* CLI commands are defined using a |CF_CLI| macro. Its parameters are:
* the list of keywords determining the command, the list of parameters,
* help text for the parameters and help text for the command.
*
* Values of |enum| filter types can be defined using |CF_ENUM| with
* the following parameters: name of filter type, prefix common for all
* literals of this type and names of all the possible values.
*/