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/*
#
# Creates an in-memory interface to a file, with largefile support.
# Uses mmap to make data available in a user-space memory window.
#
# $Id: Parser.cpp 347 2009-03-02 23:27:14Z keescook $
#
# Copyright (C) 2001-2009 Kees Cook
# kees@outflux.net, http://outflux.net/
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# http://www.gnu.org/copyleft/gpl.html
#
*/
#include "GOPchop.h"
#include "Parser.h"
// FIXME: do config.h magic...
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#undef MEMORY_UPDATE
#ifdef MEMORY_UPDATE
# define MMAP_PROT (PROT_READ|PROT_WRITE)
# define OPEN_MODE (O_RDWR)
#else
# define MMAP_PROT (PROT_READ)
# define OPEN_MODE (O_RDONLY)
#endif
Parser::Parser(size_t window)
{
// set passed-in values
mmap_max = window;
// set detected values
pagesize = getpagesize();
// set values that "reset" depends on
filename = NULL;
fd = -1;
mmap_ptr = NULL;
mmap_len = 0;
mmap_offset = 0;
error = NULL;
reset();
}
void Parser::reset()
{
if (filename)
{
free(filename);
filename = NULL;
}
if (fd > -1)
{
close(fd);
fd = -1;
}
filesize = 0;
if (mmap_ptr)
{
if (munmap(mmap_ptr, mmap_len))
perror("munmap");
mmap_ptr = NULL;
mmap_len = 0;
mmap_offset = 0;
}
location = 0;
start = NULL;
report_errors = TRUE;
parsing_state=PARSER_STATE_UNLOADED;
clearError();
}
Parser::~Parser()
{
reset();
}
int Parser::getParsingState()
{
return parsing_state;
}
#define MIN(a,b) ((a)<(b) ? (a) : (b))
int Parser::init(char *pathname, void (*ticker) (char *, float))
{
struct stat st;
tick = ticker;
// make sure we're not already running
if (filename || fd > -1 || mmap_ptr)
{
reset();
addError("%s", _("already initialized\n"));
return FALSE;
}
// open file
if ((fd = open(pathname, OPEN_MODE)) < 0)
{
reset();
addError(_("cannot open '%s': %s\n"), pathname, strerror(errno));
#ifdef MEMORY_UPDATE
addError("%s",
_
(" (write permissions are needed, but the original file won't be changed.)\n"));
#endif
return FALSE;
}
// get file size
if (fstat(fd, &st))
{
reset();
addError(_("cannot get file size: %s\n"), strerror(errno));
return FALSE;
}
if (!S_ISREG(st.st_mode))
{
reset();
addError(_("'%s' is not a file!\n"), pathname);
return FALSE;
}
filesize = st.st_size;
mmap_len = MIN(mmap_max, filesize);
if ((mmap_ptr = (uint8_t *) mmap(NULL, mmap_len, MMAP_PROT,
MAP_PRIVATE, fd, 0)) == MAP_FAILED)
{
reset();
addError("%s", _("cannot memory map file\n"));
return FALSE;
}
filename = strdup(pathname);
start = mmap_ptr;
location = 0;
parsing_state=PARSER_STATE_READY;
return TRUE;
}
char *Parser::getFilename()
{
return filename;
}
char *Parser::getError()
{
return error;
}
off_t Parser::getSize()
{
return filesize;
}
#define MAX(a,b) ((a) > (b) ? (a) : (b))
uint8_t *Parser::bytesAvail(off_t location, size_t bytes)
{
off_t pagedloc;
size_t pagedbytes;
// make sure we're in bounds
if (!mmap_ptr || location > filesize || location + bytes > filesize)
{
/*
printf("%s",_("out of bounds\n"));
printf(_("filesize: %llu\n"),filesize);
printf(_("location: %llu\n"),location);
printf(_("bytes: %d\n"),bytes);
*/
return NULL;
}
// are we inbounds in current mmap region?
if (mmap_offset <= location && location + bytes <= mmap_offset + mmap_len)
{
start = mmap_ptr + (location - mmap_offset);
return start;
}
// we're not inbounds, let's realign on page boundry, near "location"
// get page-aligned location
pagedloc = location / pagesize;
pagedloc *= pagesize;
// figure out our expected mmap window size
pagedbytes = MAX(mmap_max, (location - pagedloc) + bytes);
// mmap area too large
if (pagedbytes > mmap_max)
{
printf(_("mmap area too large (must increase window size!)\n"
"pagedbytes: %d mmap_max: %d\n"
"location: %llu pagedloc: %llu\n"
"bytes: %d\n"),
pagedbytes, mmap_max, location, pagedloc, bytes);
return NULL;
}
// unmmmap or fail
if (munmap(mmap_ptr, mmap_len))
{
printf("%s", _("munmap failed\n"));
reset();
addError("%s", _("munmap\n"));
return NULL;
}
mmap_len = pagedbytes;
mmap_offset = pagedloc;
// remmap or fail
if ((mmap_ptr = (uint8_t *) mmap(NULL, mmap_len, MMAP_PROT,
MAP_PRIVATE, fd,
mmap_offset)) == MAP_FAILED)
{
printf("%s", _("mmap failed\n"));
reset();
addError("%s", _("cannot memory map file\n"));
return NULL;
}
/*
fprintf(stderr,_("remapped %d from %llu @ 0x%08x\n"),
mmap_len, mmap_offset, (unsigned int)mmap_ptr);
*/
start = mmap_ptr + (location - mmap_offset);
return start;
}
void Parser::clearError()
{
if (error)
{
free(error);
error = NULL;
}
}
void Parser::addError(const char *fmt, ...)
{
char buf[1024];
va_list vaptr;
int len;
int leftoff = 0;
if (!report_errors)
return;
buf[0] = '\0'; // preterminate for fun
va_start(vaptr, fmt);
vsnprintf(buf, 1024, fmt, vaptr);
va_end(vaptr);
len = strlen(buf) + 1; // one for NULL
if (error)
{
leftoff = strlen(error);
len += leftoff;
}
if (!(error = (char *) realloc(error, len)))
{
// if we can't get memory for an error, we probably
// can't do much of anything anyway.
perror("realloc");
exit(1);
}
error[leftoff] = '\0'; // terminate our (possibly) new memory
// this is safe now, since we used add's len to allocate it
strcat(error, buf);
// send out the stderr too
fprintf(stderr, "%s", buf);
}
int Parser::consume(size_t bytes, uint8_t * match)
{
// no bytes? SURE!
if (!bytes)
return TRUE;
if (!bytesAvail(location, bytes) || memcmp(start, match, bytes))
return FALSE;
start += bytes;
location += bytes;
return TRUE;
}
int Parser::verify(uint8_t * source, size_t bytes, uint8_t * match)
{
// no bytes? SURE!
if (!bytes)
return TRUE;
if (memcmp(source, match, bytes) == 0)
return TRUE;
return FALSE;
}
// Returns "start" before incrementing by "bytes"
uint8_t *Parser::attach(size_t bytes)
{
uint8_t *ptr;
if ((ptr = examine(bytes)))
{
start += bytes;
location += bytes;
}
return ptr;
}
// returns points to memory but does not increment
uint8_t *Parser::examine(size_t bytes)
{
uint8_t *ptr = NULL;
// no bytes? bad...
if (bytes && bytesAvail(location, bytes))
{
ptr = start;
}
return ptr;
}
// Checks for "bytes" many bytes into the future to match "match"
int Parser::forwardMatch(size_t bytes, uint8_t * match)
{
// no bytes? SURE!
if (!bytes)
return TRUE;
if (bytesAvail(location, bytes) && !memcmp(start, match, bytes))
{
return TRUE;
}
else
return FALSE;
}
// Checks for up to 8 bits in the next byte, matching "value"
int Parser::forwardBitMatch(int bits, uint8_t value)
{
uint8_t match;
uint8_t mask;
// 0 bits? SURE!
if (!bits)
return TRUE;
if (!bytesAvail(location, 1))
return FALSE;
match = value << (8 - bits);
mask = (0xFF >> (8 - bits)) << (8 - bits);
/*
int result=((*start & mask) == match);
printf(_("*start: %d mask: %d match: %d result: %d\n"),
*start, mask, match, result);
*/
return ((*start & mask) == match);
}
// external access to the parsing state. This can only be set if
// Parser is "READY" or "PARSING". Once set to "FINISHED", it must
// be ->reset to clear it.
void Parser::setParsingState(int state)
{
if ((parsing_state==PARSER_STATE_READY &&
state==PARSER_STATE_PARSING) ||
(parsing_state==PARSER_STATE_PARSING &&
state==PARSER_STATE_FINISHED))
{
parsing_state=state;
}
}
/* vi:set ai ts=4 sw=4 expandtab: */
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