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glib/gio/xdgmime/xdgmimemagic.c

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/* -*- mode: C; c-file-style: "gnu" -*- */
/* xdgmimemagic.: Private file. Datastructure for storing magic files.
*
* More info can be found at http://www.freedesktop.org/standards/
*
* Copyright (C) 2003 Red Hat, Inc.
* Copyright (C) 2003 Jonathan Blandford <jrb@alum.mit.edu>
*
* Licensed under the Academic Free License version 2.0
* Or under the following terms:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include "xdgmimemagic.h"
#include "xdgmimeint.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#ifndef FALSE
#define FALSE (0)
#endif
#ifndef TRUE
#define TRUE (!FALSE)
#endif
#if !defined getc_unlocked && !defined HAVE_GETC_UNLOCKED
# define getc_unlocked(fp) getc (fp)
#endif
typedef struct XdgMimeMagicMatch XdgMimeMagicMatch;
typedef struct XdgMimeMagicMatchlet XdgMimeMagicMatchlet;
typedef enum
{
XDG_MIME_MAGIC_SECTION,
XDG_MIME_MAGIC_MAGIC,
XDG_MIME_MAGIC_ERROR,
XDG_MIME_MAGIC_EOF
} XdgMimeMagicState;
struct XdgMimeMagicMatch
{
const char *mime_type;
int priority;
XdgMimeMagicMatchlet *matchlet;
XdgMimeMagicMatch *next;
};
struct XdgMimeMagicMatchlet
{
int indent;
int offset;
unsigned int value_length;
unsigned char *value;
unsigned char *mask;
unsigned int range_length;
unsigned int word_size;
XdgMimeMagicMatchlet *next;
};
struct XdgMimeMagic
{
XdgMimeMagicMatch *match_list;
int max_extent;
};
static XdgMimeMagicMatch *
_xdg_mime_magic_match_new (void)
{
return calloc (1, sizeof (XdgMimeMagicMatch));
}
static XdgMimeMagicMatchlet *
_xdg_mime_magic_matchlet_new (void)
{
XdgMimeMagicMatchlet *matchlet;
matchlet = malloc (sizeof (XdgMimeMagicMatchlet));
matchlet->indent = 0;
matchlet->offset = 0;
matchlet->value_length = 0;
matchlet->value = NULL;
matchlet->mask = NULL;
matchlet->range_length = 1;
matchlet->word_size = 1;
matchlet->next = NULL;
return matchlet;
}
static void
_xdg_mime_magic_matchlet_free (XdgMimeMagicMatchlet *mime_magic_matchlet)
{
if (mime_magic_matchlet)
{
if (mime_magic_matchlet->next)
_xdg_mime_magic_matchlet_free (mime_magic_matchlet->next);
if (mime_magic_matchlet->value)
free (mime_magic_matchlet->value);
if (mime_magic_matchlet->mask)
free (mime_magic_matchlet->mask);
free (mime_magic_matchlet);
}
}
/* Frees mime_magic_match and the remainder of its list
*/
static void
_xdg_mime_magic_match_free (XdgMimeMagicMatch *mime_magic_match)
{
XdgMimeMagicMatch *ptr, *next;
ptr = mime_magic_match;
while (ptr)
{
next = ptr->next;
if (ptr->mime_type)
free ((void *) ptr->mime_type);
if (ptr->matchlet)
_xdg_mime_magic_matchlet_free (ptr->matchlet);
free (ptr);
ptr = next;
}
}
/* Reads in a hunk of data until a newline character or a '\000' is hit. The
* returned string is null terminated, and doesn't include the newline.
*/
static unsigned char *
_xdg_mime_magic_read_to_newline (FILE *magic_file,
int *end_of_file)
{
unsigned char *retval;
int c;
int len, pos;
len = 128;
pos = 0;
retval = malloc (len);
*end_of_file = FALSE;
while (TRUE)
{
c = getc_unlocked (magic_file);
if (c == EOF)
{
*end_of_file = TRUE;
break;
}
if (c == '\n' || c == '\000')
break;
retval[pos++] = (unsigned char) c;
if (pos % 128 == 127)
{
len = len + 128;
retval = realloc (retval, len);
}
}
retval[pos] = '\000';
return retval;
}
/* Returns the number read from the file, or -1 if no number could be read.
*/
static int
_xdg_mime_magic_read_a_number (FILE *magic_file,
int *end_of_file)
{
/* LONG_MAX is about 20 characters on my system */
#define MAX_NUMBER_SIZE 30
char number_string[MAX_NUMBER_SIZE + 1];
int pos = 0;
int c;
long retval = -1;
while (TRUE)
{
c = getc_unlocked (magic_file);
if (c == EOF)
{
*end_of_file = TRUE;
break;
}
if (! isdigit (c))
{
ungetc (c, magic_file);
break;
}
number_string[pos] = (char) c;
pos++;
if (pos == MAX_NUMBER_SIZE)
break;
}
if (pos > 0)
{
number_string[pos] = '\000';
errno = 0;
retval = strtol (number_string, NULL, 10);
if ((retval < INT_MIN) || (retval > INT_MAX) || (errno != 0))
return -1;
}
return retval;
}
/* Headers are of the format:
* [<priority>:<mime-type>]
*/
static XdgMimeMagicState
_xdg_mime_magic_parse_header (FILE *magic_file, XdgMimeMagicMatch *match)
{
int c;
char *buffer;
char *end_ptr;
int end_of_file = 0;
assert (magic_file != NULL);
assert (match != NULL);
c = getc_unlocked (magic_file);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
if (c != '[')
return XDG_MIME_MAGIC_ERROR;
match->priority = _xdg_mime_magic_read_a_number (magic_file, &end_of_file);
if (end_of_file)
return XDG_MIME_MAGIC_EOF;
if (match->priority == -1)
return XDG_MIME_MAGIC_ERROR;
c = getc_unlocked (magic_file);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
if (c != ':')
return XDG_MIME_MAGIC_ERROR;
buffer = (char *)_xdg_mime_magic_read_to_newline (magic_file, &end_of_file);
if (end_of_file)
{
free (buffer);
return XDG_MIME_MAGIC_EOF;
}
end_ptr = buffer;
while (*end_ptr != ']' && *end_ptr != '\000' && *end_ptr != '\n')
end_ptr++;
if (*end_ptr != ']')
{
free (buffer);
return XDG_MIME_MAGIC_ERROR;
}
*end_ptr = '\000';
match->mime_type = strdup (buffer);
free (buffer);
return XDG_MIME_MAGIC_MAGIC;
}
static XdgMimeMagicState
_xdg_mime_magic_parse_error (FILE *magic_file)
{
int c;
while (1)
{
c = getc_unlocked (magic_file);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
if (c == '\n')
return XDG_MIME_MAGIC_SECTION;
}
}
/* Headers are of the format:
* [ indent ] ">" start-offset "=" value
* [ "&" mask ] [ "~" word-size ] [ "+" range-length ] "\n"
*/
static XdgMimeMagicState
_xdg_mime_magic_parse_magic_line (FILE *magic_file,
XdgMimeMagicMatch *match)
{
XdgMimeMagicMatchlet *matchlet;
int c;
int end_of_file;
int indent = 0;
int bytes_read;
assert (magic_file != NULL);
/* Sniff the buffer to make sure it's a valid line */
c = getc_unlocked (magic_file);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
else if (c == '[')
{
ungetc (c, magic_file);
return XDG_MIME_MAGIC_SECTION;
}
else if (c == '\n')
return XDG_MIME_MAGIC_MAGIC;
/* At this point, it must be a digit or a '>' */
end_of_file = FALSE;
if (isdigit (c))
{
ungetc (c, magic_file);
indent = _xdg_mime_magic_read_a_number (magic_file, &end_of_file);
if (end_of_file)
return XDG_MIME_MAGIC_EOF;
if (indent == -1)
return XDG_MIME_MAGIC_ERROR;
c = getc_unlocked (magic_file);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
}
if (c != '>')
return XDG_MIME_MAGIC_ERROR;
matchlet = _xdg_mime_magic_matchlet_new ();
matchlet->indent = indent;
matchlet->offset = _xdg_mime_magic_read_a_number (magic_file, &end_of_file);
if (end_of_file)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
if (matchlet->offset == -1)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
c = getc_unlocked (magic_file);
if (c == EOF)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
else if (c != '=')
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
/* Next two bytes determine how long the value is */
matchlet->value_length = 0;
c = getc_unlocked (magic_file);
if (c == EOF)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
matchlet->value_length = c & 0xFF;
matchlet->value_length = matchlet->value_length << 8;
c = getc_unlocked (magic_file);
if (c == EOF)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
matchlet->value_length = matchlet->value_length + (c & 0xFF);
matchlet->value = malloc (matchlet->value_length);
/* OOM */
if (matchlet->value == NULL)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
bytes_read = fread (matchlet->value, 1, matchlet->value_length, magic_file);
if (bytes_read != matchlet->value_length)
{
_xdg_mime_magic_matchlet_free (matchlet);
if (feof (magic_file))
return XDG_MIME_MAGIC_EOF;
else
return XDG_MIME_MAGIC_ERROR;
}
c = getc_unlocked (magic_file);
if (c == '&')
{
matchlet->mask = malloc (matchlet->value_length);
/* OOM */
if (matchlet->mask == NULL)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
bytes_read = fread (matchlet->mask, 1, matchlet->value_length, magic_file);
if (bytes_read != matchlet->value_length)
{
_xdg_mime_magic_matchlet_free (matchlet);
if (feof (magic_file))
return XDG_MIME_MAGIC_EOF;
else
return XDG_MIME_MAGIC_ERROR;
}
c = getc_unlocked (magic_file);
}
if (c == '~')
{
matchlet->word_size = _xdg_mime_magic_read_a_number (magic_file, &end_of_file);
if (end_of_file)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
if (matchlet->word_size != 0 &&
matchlet->word_size != 1 &&
matchlet->word_size != 2 &&
matchlet->word_size != 4)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
c = getc_unlocked (magic_file);
}
if (c == '+')
{
matchlet->range_length = _xdg_mime_magic_read_a_number (magic_file, &end_of_file);
if (end_of_file)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_EOF;
}
if (matchlet->range_length == -1)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
c = getc_unlocked (magic_file);
}
if (c == '\n')
{
/* We clean up the matchlet, byte swapping if needed */
if (matchlet->word_size > 1)
{
#if LITTLE_ENDIAN
int i;
#endif
if (matchlet->value_length % matchlet->word_size != 0)
{
_xdg_mime_magic_matchlet_free (matchlet);
return XDG_MIME_MAGIC_ERROR;
}
/* FIXME: need to get this defined in a <config.h> style file */
#if LITTLE_ENDIAN
for (i = 0; i < matchlet->value_length; i = i + matchlet->word_size)
{
if (matchlet->word_size == 2)
*((xdg_uint16_t *) matchlet->value + i) = SWAP_BE16_TO_LE16 (*((xdg_uint16_t *) (matchlet->value + i)));
else if (matchlet->word_size == 4)
*((xdg_uint32_t *) matchlet->value + i) = SWAP_BE32_TO_LE32 (*((xdg_uint32_t *) (matchlet->value + i)));
if (matchlet->mask)
{
if (matchlet->word_size == 2)
*((xdg_uint16_t *) matchlet->mask + i) = SWAP_BE16_TO_LE16 (*((xdg_uint16_t *) (matchlet->mask + i)));
else if (matchlet->word_size == 4)
*((xdg_uint32_t *) matchlet->mask + i) = SWAP_BE32_TO_LE32 (*((xdg_uint32_t *) (matchlet->mask + i)));
}
}
#endif
}
matchlet->next = match->matchlet;
match->matchlet = matchlet;
return XDG_MIME_MAGIC_MAGIC;
}
_xdg_mime_magic_matchlet_free (matchlet);
if (c == EOF)
return XDG_MIME_MAGIC_EOF;
return XDG_MIME_MAGIC_ERROR;
}
static int
_xdg_mime_magic_matchlet_compare_to_data (XdgMimeMagicMatchlet *matchlet,
const void *data,
size_t len)
{
int i, j;
for (i = matchlet->offset; i < matchlet->offset + matchlet->range_length; i++)
{
int valid_matchlet = TRUE;
if (i + matchlet->value_length > len)
return FALSE;
if (matchlet->mask)
{
for (j = 0; j < matchlet->value_length; j++)
{
if ((matchlet->value[j] & matchlet->mask[j]) !=
((((unsigned char *) data)[j + i]) & matchlet->mask[j]))
{
valid_matchlet = FALSE;
break;
}
}
}
else
{
for (j = 0; j < matchlet->value_length; j++)
{
if (matchlet->value[j] != ((unsigned char *) data)[j + i])
{
valid_matchlet = FALSE;
break;
}
}
}
if (valid_matchlet)
return TRUE;
}
return FALSE;
}
static int
_xdg_mime_magic_matchlet_compare_level (XdgMimeMagicMatchlet *matchlet,
const void *data,
size_t len,
int indent)
{
while ((matchlet != NULL) && (matchlet->indent == indent))
{
if (_xdg_mime_magic_matchlet_compare_to_data (matchlet, data, len))
{
if ((matchlet->next == NULL) ||
(matchlet->next->indent <= indent))
return TRUE;
if (_xdg_mime_magic_matchlet_compare_level (matchlet->next,
data,
len,
indent + 1))
return TRUE;
}
do
{
matchlet = matchlet->next;
}
while (matchlet && matchlet->indent > indent);
}
return FALSE;
}
static int
_xdg_mime_magic_match_compare_to_data (XdgMimeMagicMatch *match,
const void *data,
size_t len)
{
return _xdg_mime_magic_matchlet_compare_level (match->matchlet, data, len, 0);
}
static void
_xdg_mime_magic_insert_match (XdgMimeMagic *mime_magic,
XdgMimeMagicMatch *match)
{
XdgMimeMagicMatch *list;
if (mime_magic->match_list == NULL)
{
mime_magic->match_list = match;
return;
}
if (match->priority > mime_magic->match_list->priority)
{
match->next = mime_magic->match_list;
mime_magic->match_list = match;
return;
}
list = mime_magic->match_list;
while (list->next != NULL)
{
if (list->next->priority < match->priority)
{
match->next = list->next;
list->next = match;
return;
}
list = list->next;
}
list->next = match;
match->next = NULL;
}
XdgMimeMagic *
_xdg_mime_magic_new (void)
{
return calloc (1, sizeof (XdgMimeMagic));
}
void
_xdg_mime_magic_free (XdgMimeMagic *mime_magic)
{
if (mime_magic) {
_xdg_mime_magic_match_free (mime_magic->match_list);
free (mime_magic);
}
}
int
_xdg_mime_magic_get_buffer_extents (XdgMimeMagic *mime_magic)
{
return mime_magic->max_extent;
}
const char *
_xdg_mime_magic_lookup_data (XdgMimeMagic *mime_magic,
const void *data,
size_t len,
int *result_prio,
const char *mime_types[],
int n_mime_types)
{
XdgMimeMagicMatch *match;
const char *mime_type;
int n;
int prio;
prio = 0;
mime_type = NULL;
for (match = mime_magic->match_list; match; match = match->next)
{
if (_xdg_mime_magic_match_compare_to_data (match, data, len))
{
prio = match->priority;
mime_type = match->mime_type;
break;
}
else
{
for (n = 0; n < n_mime_types; n++)
{
if (mime_types[n] &&
_xdg_mime_mime_type_equal (mime_types[n], match->mime_type))
mime_types[n] = NULL;
}
}
}
if (mime_type == NULL)
{
for (n = 0; n < n_mime_types; n++)
{
if (mime_types[n])
mime_type = mime_types[n];
}
}
if (result_prio)
*result_prio = prio;
return mime_type;
}
static void
_xdg_mime_update_mime_magic_extents (XdgMimeMagic *mime_magic)
{
XdgMimeMagicMatch *match;
int max_extent = 0;
for (match = mime_magic->match_list; match; match = match->next)
{
XdgMimeMagicMatchlet *matchlet;
for (matchlet = match->matchlet; matchlet; matchlet = matchlet->next)
{
int extent;
extent = matchlet->value_length + matchlet->offset + matchlet->range_length;
if (max_extent < extent)
max_extent = extent;
}
}
mime_magic->max_extent = max_extent;
}
static XdgMimeMagicMatchlet *
_xdg_mime_magic_matchlet_mirror (XdgMimeMagicMatchlet *matchlets)
{
XdgMimeMagicMatchlet *new_list;
XdgMimeMagicMatchlet *tmp;
if ((matchlets == NULL) || (matchlets->next == NULL))
return matchlets;
new_list = NULL;
tmp = matchlets;
while (tmp != NULL)
{
XdgMimeMagicMatchlet *matchlet;
matchlet = tmp;
tmp = tmp->next;
matchlet->next = new_list;
new_list = matchlet;
}
return new_list;
}
static void
_xdg_mime_magic_read_magic_file (XdgMimeMagic *mime_magic,
FILE *magic_file)
{
XdgMimeMagicState state;
XdgMimeMagicMatch *match = NULL; /* Quiet compiler */
state = XDG_MIME_MAGIC_SECTION;
while (state != XDG_MIME_MAGIC_EOF)
{
switch (state)
{
case XDG_MIME_MAGIC_SECTION:
match = _xdg_mime_magic_match_new ();
state = _xdg_mime_magic_parse_header (magic_file, match);
if (state == XDG_MIME_MAGIC_EOF || state == XDG_MIME_MAGIC_ERROR)
_xdg_mime_magic_match_free (match);
break;
case XDG_MIME_MAGIC_MAGIC:
state = _xdg_mime_magic_parse_magic_line (magic_file, match);
if (state == XDG_MIME_MAGIC_SECTION ||
(state == XDG_MIME_MAGIC_EOF && match->mime_type))
{
match->matchlet = _xdg_mime_magic_matchlet_mirror (match->matchlet);
_xdg_mime_magic_insert_match (mime_magic, match);
}
else if (state == XDG_MIME_MAGIC_EOF || state == XDG_MIME_MAGIC_ERROR)
_xdg_mime_magic_match_free (match);
break;
case XDG_MIME_MAGIC_ERROR:
state = _xdg_mime_magic_parse_error (magic_file);
break;
case XDG_MIME_MAGIC_EOF:
default:
/* Make the compiler happy */
assert (0);
}
}
_xdg_mime_update_mime_magic_extents (mime_magic);
}
void
_xdg_mime_magic_read_from_file (XdgMimeMagic *mime_magic,
const char *file_name)
{
FILE *magic_file;
char header[12];
magic_file = fopen (file_name, "r");
if (magic_file == NULL)
return;
if (fread (header, 1, 12, magic_file) == 12)
{
if (memcmp ("MIME-Magic\0\n", header, 12) == 0)
_xdg_mime_magic_read_magic_file (mime_magic, magic_file);
}
fclose (magic_file);
}
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