#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include "strntol.h"
#include "pattern.h"
#include "../minmax.h"
#include "../oslib/strcasestr.h"
/**
* parse_string() - parses string in double quotes, like "abc"
* @beg - string input
* @out - output buffer where parsed number should be put
* @out_len - length of the output buffer
* @filled - pointer where number of bytes successfully
* parsed will be put
*
* Returns the end pointer where parsing has been stopped.
* In case of parsing error or lack of bytes in output buffer
* NULL will be returned.
*/
static const char *parse_string(const char *beg, char *out,
unsigned int out_len,
unsigned int *filled)
{
const char *end;
if (!out_len)
return NULL;
assert(*beg == '"');
beg++;
end = strchr(beg, '"');
if (!end)
return NULL;
if (end - beg > out_len)
return NULL;
memcpy(out, beg, end - beg);
*filled = end - beg;
/* Catch up quote */
return end + 1;
}
/**
* parse_number() - parses numbers
* @beg - string input
* @out - output buffer where parsed number should be put
* @out_len - length of the output buffer
* @filled - pointer where number of bytes successfully
* parsed will be put
*
* Supports decimals in the range [INT_MIN, INT_MAX] and
* hexidecimals of any size, which should be started with
* prefix 0x or 0X.
*
* Returns the end pointer where parsing has been stopped.
* In case of parsing error or lack of bytes in output buffer
* NULL will be returned.
*/
static const char *parse_number(const char *beg, char *out,
unsigned int out_len,
unsigned int *filled)
{
const char *end;
unsigned int val;
long lval;
int num, i;
if (!out_len)
return NULL;
num = 0;
sscanf(beg, "0%*[xX]%*[0-9a-fA-F]%n", &num);
if (num == 0) {
/* Here we are trying to parse decimal */
char *_end;
/* Looking ahead */
_end = strcasestr(beg, "0x");
if (_end)
num = _end - beg;
if (num)
lval = strntol(beg, num, &_end, 10);
else
lval = strtol(beg, &_end, 10);
if (beg == _end || lval > INT_MAX || lval < INT_MIN)
return NULL;
end = _end;
i = 0;
if (!lval) {
num = 0;
out[i] = 0x00;
i = 1;
} else {
val = (unsigned int)lval;
for (; val && out_len; out_len--, i++, val >>= 8)
out[i] = val & 0xff;
if (val)
return NULL;
}
} else {
assert(num > 2);
/* Catch up 0x prefix */
num -= 2;
beg += 2;
/* Look back, handle this combined string: 0xff0x14 */
if (beg[num] && !strncasecmp(&beg[num - 1], "0x", 2))
num--;
end = beg + num;
for (i = 0; num && out_len;
out_len--, i++, num -= 2, beg += 2) {
const char *fmt;
fmt = (num & 1 ? "%1hhx" : "%2hhx");
sscanf(beg, fmt, &out[i]);
if (num & 1) {
num++;
beg--;
}
}
if (num)
return NULL;
}
*filled = i;
return end;
}
/**
* parse_format() - parses formats, like %o, etc
* @in - string input
* @out - output buffer where space for format should be reserved
* @parsed - number of bytes which were already parsed so far
* @out_len - length of the output buffer
* @fmt_desc - format descritor array, what we expect to find
* @fmt_desc_sz - size of the format descritor array
* @fmt - format array, the output
* @fmt_sz - size of format array
*
* This function tries to find formats, e.g.:
* %o - offset of the block
*
* In case of successfull parsing it fills the format param
* with proper offset and the size of the expected value, which
* should be pasted into buffer using the format 'func' callback.
*
* Returns the end pointer where parsing has been stopped.
* In case of parsing error or lack of bytes in output buffer
* NULL will be returned.
*/
static const char *parse_format(const char *in, char *out, unsigned int parsed,
unsigned int out_len, unsigned int *filled,
const struct pattern_fmt_desc *fmt_desc,
unsigned int fmt_desc_sz,
struct pattern_fmt *fmt, unsigned int fmt_sz)
{
int i;
struct pattern_fmt *f = NULL;
unsigned int len = 0;
if (!out_len || !fmt_desc || !fmt_desc_sz || !fmt || !fmt_sz)
return NULL;
assert(*in == '%');
for (i = 0; i < fmt_desc_sz; i++) {
const struct pattern_fmt_desc *desc;
desc = &fmt_desc[i];
len = strlen(desc->fmt);
if (0 == strncmp(in, desc->fmt, len)) {
fmt->desc = desc;
fmt->off = parsed;
f = fmt;
break;
}
}
if (!f)
return NULL;
if (f->desc->len > out_len)
return NULL;
memset(out, '\0', f->desc->len);
*filled = f->desc->len;
return in + len;
}
/**
* parse_and_fill_pattern() - Parses combined input, which consists of strings,
* numbers and pattern formats.
* @in - string input
* @in_len - size of the input string
* @out - output buffer where parsed result will be put
* @out_len - lengths of the output buffer
* @fmt_desc - array of pattern format descriptors [input]
* @fmt_desc_sz - size of the format descriptor array
* @fmt - array of pattern formats [output]
* @fmt_sz - pointer where the size of pattern formats array stored [input],
* after successfull parsing this pointer will contain the number
* of parsed formats if any [output].
*
* strings:
* bytes sequence in double quotes, e.g. "123".
* NOTE: there is no way to escape quote, so "123\"abc" does not work.
*
* numbers:
* hexidecimal - sequence of hex bytes starting from 0x or 0X prefix,
* e.g. 0xff12ceff1100ff
* decimal - decimal number in range [INT_MIN, INT_MAX]
*
* formats:
* %o - offset of block, reserved 8 bytes.
*
* Explicit examples of combined string:
* #1 #2 #3 #4
* in="abcd" in=-1024 in=66 in=0xFF0X1
* out=61 62 63 64 out=00 fc ff ff out=42 out=ff 01
*
* #5 #6
* in=%o in="123"0xFFeeCC
* out=00 00 00 00 00 00 00 00 out=31 32 33 ff ec cc
*
* #7
* in=-100xab"1"%o"2"
* out=f6 ff ff ff ab 31 00 00 00 00 00 00 00 00 32
*
* #9
* in=%o0xdeadbeef%o
* out=00 00 00 00 00 00 00 00 de ad be ef 00 00 00 00 00 00 00 00
*
* #10
* in=0xfefefefefefefefefefefefefefefefefefefefefe
* out=fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
*
* Returns number of bytes filled or err < 0 in case of failure.
*/
int parse_and_fill_pattern(const char *in, unsigned int in_len,
char *out, unsigned int out_len,
const struct pattern_fmt_desc *fmt_desc,
unsigned int fmt_desc_sz,
struct pattern_fmt *fmt,
unsigned int *fmt_sz_out)
{
const char *beg, *end, *out_beg = out;
unsigned int total = 0, fmt_rem = 0;
if (!in || !in_len || !out || !out_len)
return -EINVAL;
if (fmt_sz_out)
fmt_rem = *fmt_sz_out;
beg = in;
do {
unsigned int filled;
int parsed_fmt;
filled = 0;
parsed_fmt = 0;
switch (*beg) {
case '"':
end = parse_string(beg, out, out_len, &filled);
break;
case '%':
end = parse_format(beg, out, out - out_beg, out_len,
&filled, fmt_desc, fmt_desc_sz,
fmt, fmt_rem);
parsed_fmt = 1;
break;
default:
end = parse_number(beg, out, out_len, &filled);
break;
}
if (!end)
return -EINVAL;
if (parsed_fmt) {
assert(fmt_rem);
fmt_rem--;
fmt++;
}
assert(end - beg <= in_len);
in_len -= end - beg;
beg = end;
assert(filled);
assert(filled <= out_len);
out_len -= filled;
out += filled;
total += filled;
} while (in_len);
if (fmt_sz_out)
*fmt_sz_out -= fmt_rem;
return total;
}
/**
* dup_pattern() - Duplicates part of the pattern all over the buffer.
*
* Returns 0 in case of success or errno < 0 in case of failure.
*/
static int dup_pattern(char *out, unsigned int out_len, unsigned int pattern_len)
{
unsigned int left, len, off;
if (out_len <= pattern_len)
/* Normal case */
return 0;
off = pattern_len;
left = (out_len - off);
len = min(left, off);
/* Duplicate leftover */
while (left) {
memcpy(out + off, out, len);
left -= len;
off <<= 1;
len = min(left, off);
}
return 0;
}
/**
* cpy_pattern() - Copies pattern to the buffer.
*
* Function copies pattern along the whole buffer.
*
* Returns 0 in case of success or errno < 0 in case of failure.
*/
int cpy_pattern(const char *pattern, unsigned int pattern_len,
char *out, unsigned int out_len)
{
unsigned int len;
if (!pattern || !pattern_len || !out || !out_len)
return -EINVAL;
/* Copy pattern */
len = min(pattern_len, out_len);
memcpy(out, pattern, len);
/* Spread filled chunk all over the buffer */
return dup_pattern(out, out_len, pattern_len);
}
/**
* cmp_pattern() - Compares pattern and buffer.
*
* For the sake of performance this function avoids any loops.
* Firstly it tries to compare the buffer itself, checking that
* buffer consists of repeating patterns along the buffer size.
*
* If the difference is not found then the function tries to compare
* buffer and pattern.
*
* Returns 0 in case of success or errno < 0 in case of failure.
*/
int cmp_pattern(const char *pattern, unsigned int pattern_size,
unsigned int off, const char *buf, unsigned int len)
{
int rc;
unsigned int size;
/* Find the difference in buffer */
if (len > pattern_size) {
rc = memcmp(buf, buf + pattern_size, len - pattern_size);
if (rc)
return -EILSEQ;
}
/* Compare second part of the pattern with buffer */
if (off) {
size = min(len, pattern_size - off);
rc = memcmp(buf, pattern + off, size);
if (rc)
return -EILSEQ;
buf += size;
len -= size;
}
/* Compare first part of the pattern or the whole pattern
* with buffer */
if (len) {
size = min(len, (off ? off : pattern_size));
rc = memcmp(buf, pattern, size);
if (rc)
return -EILSEQ;
}
return 0;
}
/**
* paste_format_inplace() - Pastes parsed formats to the pattern.
*
* This function pastes formats to the pattern. If @fmt_sz is 0
* function does nothing and pattern buffer is left untouched.
*
* Returns 0 in case of success or errno < 0 in case of failure.
*/
int paste_format_inplace(char *pattern, unsigned int pattern_len,
struct pattern_fmt *fmt, unsigned int fmt_sz,
void *priv)
{
int i, rc;
unsigned int len;
if (!pattern || !pattern_len || !fmt)
return -EINVAL;
/* Paste formats for first pattern chunk */
for (i = 0; i < fmt_sz; i++) {
struct pattern_fmt *f;
f = &fmt[i];
if (pattern_len <= f->off)
break;
len = min(pattern_len - f->off, f->desc->len);
rc = f->desc->paste(pattern + f->off, len, priv);
if (rc)
return rc;
}
return 0;
}
/**
* paste_format() - Pastes parsed formats to the buffer.
*
* This function copies pattern to the buffer, pastes format
* into it and then duplicates pattern all over the buffer size.
*
* Returns 0 in case of success or errno < 0 in case of failure.
*/
int paste_format(const char *pattern, unsigned int pattern_len,
struct pattern_fmt *fmt, unsigned int fmt_sz,
char *out, unsigned int out_len, void *priv)
{
int rc;
unsigned int len;
if (!pattern || !pattern_len || !out || !out_len)
return -EINVAL;
/* Copy pattern */
len = min(pattern_len, out_len);
memcpy(out, pattern, len);
rc = paste_format_inplace(out, len, fmt, fmt_sz, priv);
if (rc)
return rc;
/* Spread filled chunk all over the buffer */
return dup_pattern(out, out_len, pattern_len);
}