Commit a5ecbe62 authored by Wolfgang Denk's avatar Wolfgang Denk Committed by Tom Rini

Add SLRE - Super Light Regular Expression library

Downloaded from http://slre.sourceforge.net/
and adapted for U-Boot environment.

Used to implement regex operations on environment variables.
Code size is ~ 3.5 KiB on PPC.

To enable this code, define the  CONFIG_REGEX  option in your board
config file.

Note:  There are more recent versions of the SLRE library available at
http://slre.googlecode.com ; unfortunately, the new code has a heavily
reorked API which makes it less usable for our purposes:
- the return code is strings, which are more difficult to process
- we don't get any information any more which sub-string of the data
  was matched by the given regex
- it is much more cumbersome to work with arbitrary expressions, where
  for example the number of substrings for capturing are not known at
  compile time
Also, there does not seem to be any real changes or improvements of
the functionality.

Because of this, we deliberately stick with the older code.

Note 2: the test code (built when SLRE_TEST is defined) was modified
to allow for more extensive testing; now we can test the regexp
matching on all lines on a text file (instead of the whole data in the
file as a single block).
Signed-off-by: Wolfgang Denk's avatarWolfgang Denk <wd@denx.de>
parent d87244d5
......@@ -930,6 +930,13 @@ The following options need to be configured:
XXX - this list needs to get updated!
- Regular expression support:
CONFIG_REGEX
If this variable is defined, U-Boot is linked against
the SLRE (Super Light Regular Expression) library,
which adds regex support to some commands, as for
example "env grep" and "setexpr".
- Device tree:
CONFIG_OF_CONTROL
If this variable is defined, U-Boot will use a device tree
......
/*
* Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
* All rights reserved
*
* "THE BEER-WARE LICENSE" (Revision 42):
* Sergey Lyubka wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return.
*/
/*
* Downloaded Sat Nov 5 17:42:08 CET 2011 at
* http://slre.sourceforge.net/1.0/slre.h
*/
/*
* This is a regular expression library that implements a subset of Perl RE.
* Please refer to http://slre.sourceforge.net for detailed description.
*
* Usage example (parsing HTTP request):
*
* struct slre slre;
* struct cap captures[4 + 1]; // Number of braket pairs + 1
* ...
*
* slre_compile(&slre,"^(GET|POST) (\S+) HTTP/(\S+?)\r\n");
*
* if (slre_match(&slre, buf, len, captures)) {
* printf("Request line length: %d\n", captures[0].len);
* printf("Method: %.*s\n", captures[1].len, captures[1].ptr);
* printf("URI: %.*s\n", captures[2].len, captures[2].ptr);
* }
*
* Supported syntax:
* ^ Match beginning of a buffer
* $ Match end of a buffer
* () Grouping and substring capturing
* [...] Match any character from set
* [^...] Match any character but ones from set
* \s Match whitespace
* \S Match non-whitespace
* \d Match decimal digit
* \r Match carriage return
* \n Match newline
* + Match one or more times (greedy)
* +? Match one or more times (non-greedy)
* * Match zero or more times (greedy)
* *? Match zero or more times (non-greedy)
* ? Match zero or once
* \xDD Match byte with hex value 0xDD
* \meta Match one of the meta character: ^$().[*+?\
*/
#ifndef SLRE_HEADER_DEFINED
#define SLRE_HEADER_DEFINED
/*
* Compiled regular expression
*/
struct slre {
unsigned char code[256];
unsigned char data[256];
int code_size;
int data_size;
int num_caps; /* Number of bracket pairs */
int anchored; /* Must match from string start */
const char *err_str; /* Error string */
};
/*
* Captured substring
*/
struct cap {
const char *ptr; /* Pointer to the substring */
int len; /* Substring length */
};
/*
* Compile regular expression. If success, 1 is returned.
* If error, 0 is returned and slre.err_str points to the error message.
*/
int slre_compile(struct slre *, const char *re);
/*
* Return 1 if match, 0 if no match.
* If `captured_substrings' array is not NULL, then it is filled with the
* values of captured substrings. captured_substrings[0] element is always
* a full matched substring. The round bracket captures start from
* captured_substrings[1].
* It is assumed that the size of captured_substrings array is enough to
* hold all captures. The caller function must make sure it is! So, the
* array_size = number_of_round_bracket_pairs + 1
*/
int slre_match(const struct slre *, const char *buf, int buf_len,
struct cap *captured_substrings);
#ifdef SLRE_TEST
void slre_dump(const struct slre *r, FILE *fp);
#endif /* SLRE_TEST */
#endif /* SLRE_HEADER_DEFINED */
......@@ -72,6 +72,7 @@ COBJS-y += crc32.o
COBJS-y += ctype.o
COBJS-y += div64.o
COBJS-y += linux_string.o
COBJS-$(CONFIG_REGEX) += slre.o
COBJS-y += string.o
COBJS-y += time.o
COBJS-$(CONFIG_BOOTP_PXE) += uuid.o
......
/*
* Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
* All rights reserved
*
* "THE BEER-WARE LICENSE" (Revision 42):
* Sergey Lyubka wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return.
*/
/*
* Downloaded Sat Nov 5 17:43:06 CET 2011 at
* http://slre.sourceforge.net/1.0/slre.c
*/
#ifdef SLRE_TEST
#include <stdio.h>
#include <assert.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#else
#include <common.h>
#include <linux/ctype.h>
#endif /* SLRE_TEST */
#include <errno.h>
#include <slre.h>
enum {END, BRANCH, ANY, EXACT, ANYOF, ANYBUT, OPEN, CLOSE, BOL, EOL,
STAR, PLUS, STARQ, PLUSQ, QUEST, SPACE, NONSPACE, DIGIT};
#ifdef SLRE_TEST
static struct {
const char *name;
int narg;
const char *flags;
} opcodes[] = {
{"END", 0, ""}, /* End of code block or program */
{"BRANCH", 2, "oo"}, /* Alternative operator, "|" */
{"ANY", 0, ""}, /* Match any character, "." */
{"EXACT", 2, "d"}, /* Match exact string */
{"ANYOF", 2, "D"}, /* Match any from set, "[]" */
{"ANYBUT", 2, "D"}, /* Match any but from set, "[^]"*/
{"OPEN ", 1, "i"}, /* Capture start, "(" */
{"CLOSE", 1, "i"}, /* Capture end, ")" */
{"BOL", 0, ""}, /* Beginning of string, "^" */
{"EOL", 0, ""}, /* End of string, "$" */
{"STAR", 1, "o"}, /* Match zero or more times "*" */
{"PLUS", 1, "o"}, /* Match one or more times, "+" */
{"STARQ", 1, "o"}, /* Non-greedy STAR, "*?" */
{"PLUSQ", 1, "o"}, /* Non-greedy PLUS, "+?" */
{"QUEST", 1, "o"}, /* Match zero or one time, "?" */
{"SPACE", 0, ""}, /* Match whitespace, "\s" */
{"NONSPACE", 0, ""}, /* Match non-space, "\S" */
{"DIGIT", 0, ""} /* Match digit, "\d" */
};
#endif /* SLRE_TEST */
/*
* Commands and operands are all unsigned char (1 byte long). All code offsets
* are relative to current address, and positive (always point forward). Data
* offsets are absolute. Commands with operands:
*
* BRANCH offset1 offset2
* Try to match the code block that follows the BRANCH instruction
* (code block ends with END). If no match, try to match code block that
* starts at offset1. If either of these match, jump to offset2.
*
* EXACT data_offset data_length
* Try to match exact string. String is recorded in data section from
* data_offset, and has length data_length.
*
* OPEN capture_number
* CLOSE capture_number
* If the user have passed 'struct cap' array for captures, OPEN
* records the beginning of the matched substring (cap->ptr), CLOSE
* sets the length (cap->len) for respective capture_number.
*
* STAR code_offset
* PLUS code_offset
* QUEST code_offset
* *, +, ?, respectively. Try to gobble as much as possible from the
* matched buffer, until code block that follows these instructions
* matches. When the longest possible string is matched,
* jump to code_offset
*
* STARQ, PLUSQ are non-greedy versions of STAR and PLUS.
*/
static const char *meta_chars = "|.^$*+?()[\\";
#ifdef SLRE_TEST
static void
print_character_set(FILE *fp, const unsigned char *p, int len)
{
int i;
for (i = 0; i < len; i++) {
if (i > 0)
(void) fputc(',', fp);
if (p[i] == 0) {
i++;
if (p[i] == 0)
(void) fprintf(fp, "\\x%02x", p[i]);
else
(void) fprintf(fp, "%s", opcodes[p[i]].name);
} else if (isprint(p[i])) {
(void) fputc(p[i], fp);
} else {
(void) fprintf(fp, "\\x%02x", p[i]);
}
}
}
void
slre_dump(const struct slre *r, FILE *fp)
{
int i, j, ch, op, pc;
for (pc = 0; pc < r->code_size; pc++) {
op = r->code[pc];
(void) fprintf(fp, "%3d %s ", pc, opcodes[op].name);
for (i = 0; opcodes[op].flags[i] != '\0'; i++)
switch (opcodes[op].flags[i]) {
case 'i':
(void) fprintf(fp, "%d ", r->code[pc + 1]);
pc++;
break;
case 'o':
(void) fprintf(fp, "%d ",
pc + r->code[pc + 1] - i);
pc++;
break;
case 'D':
print_character_set(fp, r->data +
r->code[pc + 1], r->code[pc + 2]);
pc += 2;
break;
case 'd':
(void) fputc('"', fp);
for (j = 0; j < r->code[pc + 2]; j++) {
ch = r->data[r->code[pc + 1] + j];
if (isprint(ch)) {
(void) fputc(ch, fp);
} else {
(void) fprintf(fp,
"\\x%02x", ch);
}
}
(void) fputc('"', fp);
pc += 2;
break;
}
(void) fputc('\n', fp);
}
}
#endif /* SLRE_TEST */
static void
set_jump_offset(struct slre *r, int pc, int offset)
{
assert(offset < r->code_size);
if (r->code_size - offset > 0xff)
r->err_str = "Jump offset is too big";
else
r->code[pc] = (unsigned char) (r->code_size - offset);
}
static void
emit(struct slre *r, int code)
{
if (r->code_size >= (int) (sizeof(r->code) / sizeof(r->code[0])))
r->err_str = "RE is too long (code overflow)";
else
r->code[r->code_size++] = (unsigned char) code;
}
static void
store_char_in_data(struct slre *r, int ch)
{
if (r->data_size >= (int) sizeof(r->data))
r->err_str = "RE is too long (data overflow)";
else
r->data[r->data_size++] = ch;
}
static void
exact(struct slre *r, const char **re)
{
int old_data_size = r->data_size;
while (**re != '\0' && (strchr(meta_chars, **re)) == NULL)
store_char_in_data(r, *(*re)++);
emit(r, EXACT);
emit(r, old_data_size);
emit(r, r->data_size - old_data_size);
}
static int
get_escape_char(const char **re)
{
int res;
switch (*(*re)++) {
case 'n':
res = '\n';
break;
case 'r':
res = '\r';
break;
case 't':
res = '\t';
break;
case '0':
res = 0;
break;
case 'S':
res = NONSPACE << 8;
break;
case 's':
res = SPACE << 8;
break;
case 'd':
res = DIGIT << 8;
break;
default:
res = (*re)[-1];
break;
}
return res;
}
static void
anyof(struct slre *r, const char **re)
{
int esc, old_data_size = r->data_size, op = ANYOF;
if (**re == '^') {
op = ANYBUT;
(*re)++;
}
while (**re != '\0')
switch (*(*re)++) {
case ']':
emit(r, op);
emit(r, old_data_size);
emit(r, r->data_size - old_data_size);
return;
/* NOTREACHED */
break;
case '\\':
esc = get_escape_char(re);
if ((esc & 0xff) == 0) {
store_char_in_data(r, 0);
store_char_in_data(r, esc >> 8);
} else {
store_char_in_data(r, esc);
}
break;
default:
store_char_in_data(r, (*re)[-1]);
break;
}
r->err_str = "No closing ']' bracket";
}
static void
relocate(struct slre *r, int begin, int shift)
{
emit(r, END);
memmove(r->code + begin + shift, r->code + begin, r->code_size - begin);
r->code_size += shift;
}
static void
quantifier(struct slre *r, int prev, int op)
{
if (r->code[prev] == EXACT && r->code[prev + 2] > 1) {
r->code[prev + 2]--;
emit(r, EXACT);
emit(r, r->code[prev + 1] + r->code[prev + 2]);
emit(r, 1);
prev = r->code_size - 3;
}
relocate(r, prev, 2);
r->code[prev] = op;
set_jump_offset(r, prev + 1, prev);
}
static void
exact_one_char(struct slre *r, int ch)
{
emit(r, EXACT);
emit(r, r->data_size);
emit(r, 1);
store_char_in_data(r, ch);
}
static void
fixup_branch(struct slre *r, int fixup)
{
if (fixup > 0) {
emit(r, END);
set_jump_offset(r, fixup, fixup - 2);
}
}
static void
compile(struct slre *r, const char **re)
{
int op, esc, branch_start, last_op, fixup, cap_no, level;
fixup = 0;
level = r->num_caps;
branch_start = last_op = r->code_size;
for (;;)
switch (*(*re)++) {
case '\0':
(*re)--;
return;
/* NOTREACHED */
break;
case '^':
emit(r, BOL);
break;
case '$':
emit(r, EOL);
break;
case '.':
last_op = r->code_size;
emit(r, ANY);
break;
case '[':
last_op = r->code_size;
anyof(r, re);
break;
case '\\':
last_op = r->code_size;
esc = get_escape_char(re);
if (esc & 0xff00)
emit(r, esc >> 8);
else
exact_one_char(r, esc);
break;
case '(':
last_op = r->code_size;
cap_no = ++r->num_caps;
emit(r, OPEN);
emit(r, cap_no);
compile(r, re);
if (*(*re)++ != ')') {
r->err_str = "No closing bracket";
return;
}
emit(r, CLOSE);
emit(r, cap_no);
break;
case ')':
(*re)--;
fixup_branch(r, fixup);
if (level == 0) {
r->err_str = "Unbalanced brackets";
return;
}
return;
/* NOTREACHED */
break;
case '+':
case '*':
op = (*re)[-1] == '*' ? STAR : PLUS;
if (**re == '?') {
(*re)++;
op = op == STAR ? STARQ : PLUSQ;
}
quantifier(r, last_op, op);
break;
case '?':
quantifier(r, last_op, QUEST);
break;
case '|':
fixup_branch(r, fixup);
relocate(r, branch_start, 3);
r->code[branch_start] = BRANCH;
set_jump_offset(r, branch_start + 1, branch_start);
fixup = branch_start + 2;
r->code[fixup] = 0xff;
break;
default:
(*re)--;
last_op = r->code_size;
exact(r, re);
break;
}
}
int
slre_compile(struct slre *r, const char *re)
{
r->err_str = NULL;
r->code_size = r->data_size = r->num_caps = r->anchored = 0;
if (*re == '^')
r->anchored++;
emit(r, OPEN); /* This will capture what matches full RE */
emit(r, 0);
while (*re != '\0')
compile(r, &re);
if (r->code[2] == BRANCH)
fixup_branch(r, 4);
emit(r, CLOSE);
emit(r, 0);
emit(r, END);
return (r->err_str == NULL ? 1 : 0);
}
static int match(const struct slre *, int,
const char *, int, int *, struct cap *);
static void
loop_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs)
{
int saved_offset, matched_offset;
saved_offset = matched_offset = *ofs;
while (match(r, pc + 2, s, len, ofs, NULL)) {
saved_offset = *ofs;
if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL))
matched_offset = saved_offset;
*ofs = saved_offset;
}
*ofs = matched_offset;
}
static void
loop_non_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs)
{
int saved_offset = *ofs;
while (match(r, pc + 2, s, len, ofs, NULL)) {
saved_offset = *ofs;
if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL))
break;
}
*ofs = saved_offset;
}
static int
is_any_of(const unsigned char *p, int len, const char *s, int *ofs)
{
int i, ch;
ch = s[*ofs];
for (i = 0; i < len; i++)
if (p[i] == ch) {
(*ofs)++;
return 1;
}
return 0;
}
static int
is_any_but(const unsigned char *p, int len, const char *s, int *ofs)
{
int i, ch;
ch = s[*ofs];
for (i = 0; i < len; i++) {
if (p[i] == ch)
return 0;
}
(*ofs)++;
return 1;
}
static int
match(const struct slre *r, int pc, const char *s, int len,
int *ofs, struct cap *caps)
{
int n, saved_offset, res = 1;
while (res && r->code[pc] != END) {
assert(pc < r->code_size);
assert(pc < (int) (sizeof(r->code) / sizeof(r->code[0])));
switch (r->code[pc]) {
case BRANCH:
saved_offset = *ofs;
res = match(r, pc + 3, s, len, ofs, caps);
if (res == 0) {
*ofs = saved_offset;
res = match(r, pc + r->code[pc + 1],
s, len, ofs, caps);
}
pc += r->code[pc + 2];
break;
case EXACT:
res = 0;
n = r->code[pc + 2]; /* String length */
if (n <= len - *ofs && !memcmp(s + *ofs, r->data +
r->code[pc + 1], n)) {
(*ofs) += n;
res = 1;
}
<