regex.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
* Copyright (C) 2013, 2014.2015, 2015, 2016 Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#include <config.h>
#include <isc/file.h>
#include <isc/print.h>
#include <isc/regex.h>
#include <isc/string.h>
#if VALREGEX_REPORT_REASON
#define FAIL(x) do { reason = (x); goto error; } while(0)
#else
#define FAIL(x) goto error
#endif
/*
* Validate the regular expression 'C' locale.
*/
int
isc_regex_validate(const char *c) {
enum {
none, parse_bracket, parse_bound,
parse_ce, parse_ec, parse_cc
} state = none;
/* Well known character classes. */
const char *cc[] = {
":alnum:", ":digit:", ":punct:", ":alpha:", ":graph:",
":space:", ":blank:", ":lower:", ":upper:", ":cntrl:",
":print:", ":xdigit:"
};
isc_boolean_t seen_comma = ISC_FALSE;
isc_boolean_t seen_high = ISC_FALSE;
isc_boolean_t seen_char = ISC_FALSE;
isc_boolean_t seen_ec = ISC_FALSE;
isc_boolean_t seen_ce = ISC_FALSE;
isc_boolean_t have_atom = ISC_FALSE;
int group = 0;
int range = 0;
int sub = 0;
isc_boolean_t empty_ok = ISC_FALSE;
isc_boolean_t neg = ISC_FALSE;
isc_boolean_t was_multiple = ISC_FALSE;
unsigned int low = 0;
unsigned int high = 0;
const char *ccname = NULL;
int range_start = 0;
#if VALREGEX_REPORT_REASON
const char *reason = "";
#endif
if (c == NULL || *c == 0)
FAIL("empty string");
while (c != NULL && *c != 0) {
switch (state) {
case none:
switch (*c) {
case '\\': /* make literal */
++c;
switch (*c) {
case '1': case '2': case '3':
case '4': case '5': case '6':
case '7': case '8': case '9':
if ((*c - '0') > sub)
FAIL("bad back reference");
have_atom = ISC_TRUE;
was_multiple = ISC_FALSE;
break;
case 0:
FAIL("escaped end-of-string");
default:
goto literal;
}
++c;
break;
case '[': /* bracket start */
++c;
neg = ISC_FALSE;
was_multiple = ISC_FALSE;
seen_char = ISC_FALSE;
state = parse_bracket;
break;
case '{': /* bound start */
switch (c[1]) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
case '8': case '9':
if (!have_atom)
FAIL("no atom");
if (was_multiple)
FAIL("was multiple");
seen_comma = ISC_FALSE;
seen_high = ISC_FALSE;
low = high = 0;
state = parse_bound;
break;
default:
goto literal;
}
++c;
have_atom = ISC_TRUE;
was_multiple = ISC_TRUE;
break;
case '}':
goto literal;
case '(': /* group start */
have_atom = ISC_FALSE;
was_multiple = ISC_FALSE;
empty_ok = ISC_TRUE;
++group;
++sub;
++c;
break;
case ')': /* group end */
if (group && !have_atom && !empty_ok)
FAIL("empty alternative");
have_atom = ISC_TRUE;
was_multiple = ISC_FALSE;
if (group != 0)
--group;
++c;
break;
case '|': /* alternative seperator */
if (!have_atom)
FAIL("no atom");
have_atom = ISC_FALSE;
empty_ok = ISC_FALSE;
was_multiple = ISC_FALSE;
++c;
break;
case '^':
case '$':
have_atom = ISC_TRUE;
was_multiple = ISC_TRUE;
++c;
break;
case '+':
case '*':
case '?':
if (was_multiple)
FAIL("was multiple");
if (!have_atom)
FAIL("no atom");
have_atom = ISC_TRUE;
was_multiple = ISC_TRUE;
++c;
break;
case '.':
default:
literal:
have_atom = ISC_TRUE;
was_multiple = ISC_FALSE;
++c;
break;
}
break;
case parse_bound:
switch (*c) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
if (!seen_comma) {
low = low * 10 + *c - '0';
if (low > 255)
FAIL("lower bound too big");
} else {
seen_high = ISC_TRUE;
high = high * 10 + *c - '0';
if (high > 255)
FAIL("upper bound too big");
}
++c;
break;
case ',':
if (seen_comma)
FAIL("multiple commas");
seen_comma = ISC_TRUE;
++c;
break;
default:
case '{':
FAIL("non digit/comma");
case '}':
if (seen_high && low > high)
FAIL("bad parse bound");
seen_comma = ISC_FALSE;
state = none;
++c;
break;
}
break;
case parse_bracket:
switch (*c) {
case '^':
if (seen_char || neg) goto inside;
neg = ISC_TRUE;
++c;
break;
case '-':
if (range == 2) goto inside;
if (!seen_char) goto inside;
if (range == 1)
FAIL("bad range");
range = 2;
++c;
break;
case '[':
++c;
switch (*c) {
case '.': /* collating element */
if (range != 0) --range;
++c;
state = parse_ce;
seen_ce = ISC_FALSE;
break;
case '=': /* equivalence class */
if (range == 2)
FAIL("equivalence class in range");
++c;
state = parse_ec;
seen_ec = ISC_FALSE;
break;
case ':': /* character class */
if (range == 2)
FAIL("character class in range");
ccname = c;
++c;
state = parse_cc;
break;
}
seen_char = ISC_TRUE;
break;
case ']':
if (!c[1] && !seen_char)
FAIL("unfinished brace");
if (!seen_char)
goto inside;
++c;
range = 0;
have_atom = ISC_TRUE;
state = none;
break;
default:
inside:
seen_char = ISC_TRUE;
if (range == 2 && (*c & 0xff) < range_start)
FAIL("out of order range");
if (range != 0)
--range;
range_start = *c & 0xff;
++c;
break;
};
break;
case parse_ce:
switch (*c) {
case '.':
++c;
switch (*c) {
case ']':
if (!seen_ce)
FAIL("empty ce");
++c;
state = parse_bracket;
break;
default:
if (seen_ce)
range_start = 256;
else
range_start = '.';
seen_ce = ISC_TRUE;
break;
}
break;
default:
if (seen_ce)
range_start = 256;
else
range_start = *c;
seen_ce = ISC_TRUE;
++c;
break;
}
break;
case parse_ec:
switch (*c) {
case '=':
++c;
switch (*c) {
case ']':
if (!seen_ec)
FAIL("no ec");
++c;
state = parse_bracket;
break;
default:
seen_ec = ISC_TRUE;
break;
}
break;
default:
seen_ec = ISC_TRUE;
++c;
break;
}
break;
case parse_cc:
switch (*c) {
case ':':
++c;
switch (*c) {
case ']': {
unsigned int i;
isc_boolean_t found = ISC_FALSE;
for (i = 0;
i < sizeof(cc)/sizeof(*cc);
i++)
{
unsigned int len;
len = strlen(cc[i]);
if (len !=
(unsigned int)(c - ccname))
continue;
if (strncmp(cc[i], ccname, len))
continue;
found = ISC_TRUE;
}
if (!found)
FAIL("unknown cc");
++c;
state = parse_bracket;
break;
}
default:
break;
}
break;
default:
++c;
break;
}
break;
}
}
if (group != 0)
FAIL("group open");
if (state != none)
FAIL("incomplete");
if (!have_atom)
FAIL("no atom");
return (sub);
error:
#if VALREGEX_REPORT_REASON
fprintf(stderr, "%s\n", reason);
#endif
return (-1);
}