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gimp/app/file/file-procedure.c

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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995, 1996, 1997 Spencer Kimball and Peter Mattis
* Copyright (C) 1997 Josh MacDonald
*
* file-procedure.c
*
* 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.
*/
#include "config.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <glib-object.h>
#include <glib/gstdio.h>
#include "libgimpbase/gimpbase.h"
#include "core/core-types.h"
#include "plug-in/gimppluginprocedure.h"
#include "file-procedure.h"
#include "file-utils.h"
#include "gimp-intl.h"
typedef enum
{
FILE_MATCH_NONE,
FILE_MATCH_MAGIC,
FILE_MATCH_SIZE
} FileMatchType;
/* local function prototypes */
static GimpPlugInProcedure * file_proc_find_by_prefix (GSList *procs,
const gchar *uri,
gboolean skip_magic);
static GimpPlugInProcedure * file_proc_find_by_extension (GSList *procs,
const gchar *uri,
gboolean skip_magic);
static GimpPlugInProcedure * file_proc_find_by_name (GSList *procs,
const gchar *uri,
gboolean skip_magic);
static void file_convert_string (const gchar *instr,
gchar *outmem,
gint maxmem,
gint *nmem);
static FileMatchType file_check_single_magic (const gchar *offset,
const gchar *type,
const gchar *value,
const guchar *file_head,
gint headsize,
FILE *ifp);
static FileMatchType file_check_magic_list (GSList *magics_list,
const guchar *head,
gint headsize,
FILE *ifp);
/* public functions */
GimpPlugInProcedure *
file_procedure_find (GSList *procs,
const gchar *uri,
GError **error)
{
GimpPlugInProcedure *file_proc;
GSList *all_procs = procs;
gchar *filename;
g_return_val_if_fail (procs != NULL, NULL);
g_return_val_if_fail (uri != NULL, NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
/* First, check magicless prefixes/suffixes */
file_proc = file_proc_find_by_name (all_procs, uri, TRUE);
if (file_proc)
return file_proc;
filename = file_utils_filename_from_uri (uri);
/* Then look for magics */
if (filename)
{
GimpPlugInProcedure *size_matched_proc = NULL;
FILE *ifp = NULL;
gint head_size = -2;
gint size_match_count = 0;
guchar head[256];
while (procs)
{
file_proc = procs->data;
procs = procs->next;
if (file_proc->magics_list)
{
if (head_size == -2)
{
head_size = 0;
if ((ifp = g_fopen (filename, "rb")) != NULL)
{
head_size = fread ((gchar *) head, 1, sizeof (head), ifp);
}
else
{
g_set_error_literal (error,
G_FILE_ERROR,
g_file_error_from_errno (errno),
g_strerror (errno));
}
}
if (head_size >= 4)
{
FileMatchType match_val;
match_val = file_check_magic_list (file_proc->magics_list,
head, head_size,
ifp);
if (match_val == FILE_MATCH_SIZE)
{
/* Use it only if no other magic matches */
size_match_count++;
size_matched_proc = file_proc;
}
else if (match_val != FILE_MATCH_NONE)
{
fclose (ifp);
g_free (filename);
return file_proc;
}
}
}
}
if (ifp)
{
if (ferror (ifp))
g_set_error_literal (error, G_FILE_ERROR,
g_file_error_from_errno (errno),
g_strerror (errno));
fclose (ifp);
}
g_free (filename);
if (size_match_count == 1)
return size_matched_proc;
}
/* As a last resort, try matching by name */
file_proc = file_proc_find_by_name (all_procs, uri, FALSE);
if (file_proc)
{
/* we found a procedure, clear error that might have been set */
g_clear_error (error);
}
else
{
/* set an error message unless one was already set */
if (error && *error == NULL)
g_set_error_literal (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
_("Unknown file type"));
}
return file_proc;
}
GimpPlugInProcedure *
file_procedure_find_by_prefix (GSList *procs,
const gchar *uri)
{
g_return_val_if_fail (uri != NULL, NULL);
return file_proc_find_by_prefix (procs, uri, FALSE);
}
GimpPlugInProcedure *
file_procedure_find_by_extension (GSList *procs,
const gchar *uri)
{
g_return_val_if_fail (uri != NULL, NULL);
return file_proc_find_by_extension (procs, uri, FALSE);
}
/* private functions */
static GimpPlugInProcedure *
file_proc_find_by_prefix (GSList *procs,
const gchar *uri,
gboolean skip_magic)
{
GSList *p;
for (p = procs; p; p = g_slist_next (p))
{
GimpPlugInProcedure *proc = p->data;
GSList *prefixes;
if (skip_magic && proc->magics_list)
continue;
for (prefixes = proc->prefixes_list;
prefixes;
prefixes = g_slist_next (prefixes))
{
if (g_str_has_prefix (uri, prefixes->data))
return proc;
}
}
return NULL;
}
static GimpPlugInProcedure *
file_proc_find_by_extension (GSList *procs,
const gchar *uri,
gboolean skip_magic)
{
GSList *p;
const gchar *ext;
ext = strrchr (uri, '.');
if (ext)
ext++;
for (p = procs; p; p = g_slist_next (p))
{
GimpPlugInProcedure *proc = p->data;
GSList *extensions;
for (extensions = proc->extensions_list;
ext && extensions;
extensions = g_slist_next (extensions))
{
const gchar *p1 = ext;
const gchar *p2 = extensions->data;
if (skip_magic && proc->magics_list)
continue;
while (*p1 && *p2)
{
if (g_ascii_tolower (*p1) != g_ascii_tolower (*p2))
break;
p1++;
p2++;
}
if (!(*p1) && !(*p2))
return proc;
}
}
return NULL;
}
static GimpPlugInProcedure *
file_proc_find_by_name (GSList *procs,
const gchar *uri,
gboolean skip_magic)
{
GimpPlugInProcedure *proc;
proc = file_proc_find_by_prefix (procs, uri, skip_magic);
if (! proc)
proc = file_proc_find_by_extension (procs, uri, skip_magic);
return proc;
}
static void
file_convert_string (const gchar *instr,
gchar *outmem,
gint maxmem,
gint *nmem)
{
/* Convert a string in C-notation to array of char */
const guchar *uin = (const guchar *) instr;
guchar *uout = (guchar *) outmem;
guchar tmp[5], *tmpptr;
guint k;
while ((*uin != '\0') && ((((gchar *) uout) - outmem) < maxmem))
{
if (*uin != '\\') /* Not an escaped character ? */
{
*(uout++) = *(uin++);
continue;
}
if (*(++uin) == '\0')
{
*(uout++) = '\\';
break;
}
switch (*uin)
{
case '0': case '1': case '2': case '3': /* octal */
for (tmpptr = tmp; (tmpptr - tmp) <= 3;)
{
*(tmpptr++) = *(uin++);
if ( (*uin == '\0') || (!g_ascii_isdigit (*uin))
|| (*uin == '8') || (*uin == '9'))
break;
}
*tmpptr = '\0';
sscanf ((gchar *) tmp, "%o", &k);
*(uout++) = k;
break;
case 'a': *(uout++) = '\a'; uin++; break;
case 'b': *(uout++) = '\b'; uin++; break;
case 't': *(uout++) = '\t'; uin++; break;
case 'n': *(uout++) = '\n'; uin++; break;
case 'v': *(uout++) = '\v'; uin++; break;
case 'f': *(uout++) = '\f'; uin++; break;
case 'r': *(uout++) = '\r'; uin++; break;
default : *(uout++) = *(uin++); break;
}
}
*nmem = ((gchar *) uout) - outmem;
}
static FileMatchType
file_check_single_magic (const gchar *offset,
const gchar *type,
const gchar *value,
const guchar *file_head,
gint headsize,
FILE *ifp)
{
FileMatchType found = FILE_MATCH_NONE;
glong offs;
gulong num_testval;
gulong num_operatorval;
gint numbytes, k;
const gchar *num_operator_ptr;
gchar num_operator;
/* Check offset */
if (sscanf (offset, "%ld", &offs) != 1)
return FILE_MATCH_NONE;
/* Check type of test */
num_operator_ptr = NULL;
num_operator = '\0';
if (g_str_has_prefix (type, "byte"))
{
numbytes = 1;
num_operator_ptr = type + strlen ("byte");
}
else if (g_str_has_prefix (type, "short"))
{
numbytes = 2;
num_operator_ptr = type + strlen ("short");
}
else if (g_str_has_prefix (type, "long"))
{
numbytes = 4;
num_operator_ptr = type + strlen ("long");
}
else if (g_str_has_prefix (type, "size"))
{
numbytes = 5;
}
else if (strcmp (type, "string") == 0)
{
numbytes = 0;
}
else
{
return FILE_MATCH_NONE;
}
/* Check numerical operator value if present */
if (num_operator_ptr && (*num_operator_ptr == '&'))
{
if (g_ascii_isdigit (num_operator_ptr[1]))
{
if (num_operator_ptr[1] != '0') /* decimal */
sscanf (num_operator_ptr+1, "%lu", &num_operatorval);
else if (num_operator_ptr[2] == 'x') /* hexadecimal */
sscanf (num_operator_ptr+3, "%lx", &num_operatorval);
else /* octal */
sscanf (num_operator_ptr+2, "%lo", &num_operatorval);
num_operator = *num_operator_ptr;
}
}
if (numbytes > 0) /* Numerical test ? */
{
gchar num_test = '=';
gulong fileval = 0;
/* Check test value */
if ((value[0] == '>') || (value[0] == '<'))
{
num_test = value[0];
value++;
}
errno = 0;
num_testval = strtol (value, NULL, 0);
if (errno != 0)
return FILE_MATCH_NONE;
if (numbytes == 5) /* Check for file size ? */
{
struct stat buf;
if (fstat (fileno (ifp), &buf) < 0)
return FILE_MATCH_NONE;
fileval = buf.st_size;
}
else if (offs >= 0 &&
(offs + numbytes <= headsize)) /* We have it in memory ? */
{
for (k = 0; k < numbytes; k++)
fileval = (fileval << 8) | (glong) file_head[offs + k];
}
else /* Read it from file */
{
gint c = 0;
if (fseek (ifp, offs, (offs >= 0) ? SEEK_SET : SEEK_END) < 0)
return FILE_MATCH_NONE;
for (k = 0; k < numbytes; k++)
fileval = (fileval << 8) | (c = getc (ifp));
if (c == EOF)
return FILE_MATCH_NONE;
}
if (num_operator == '&')
fileval &= num_operatorval;
if (num_test == '<')
found = (fileval < num_testval);
else if (num_test == '>')
found = (fileval > num_testval);
else
found = (fileval == num_testval);
if (found && (numbytes == 5))
found = FILE_MATCH_SIZE;
}
else if (numbytes == 0) /* String test */
{
gchar mem_testval[256];
file_convert_string (value,
mem_testval, sizeof (mem_testval),
&numbytes);
if (numbytes <= 0)
return FILE_MATCH_NONE;
if (offs >= 0 &&
(offs + numbytes <= headsize)) /* We have it in memory ? */
{
found = (memcmp (mem_testval, file_head + offs, numbytes) == 0);
}
else /* Read it from file */
{
if (fseek (ifp, offs, (offs >= 0) ? SEEK_SET : SEEK_END) < 0)
return FILE_MATCH_NONE;
found = FILE_MATCH_MAGIC;
for (k = 0; found && (k < numbytes); k++)
{
gint c = getc (ifp);
found = (c != EOF) && (c == (gint) mem_testval[k]);
}
}
}
return found;
}
static FileMatchType
file_check_magic_list (GSList *magics_list,
const guchar *head,
gint headsize,
FILE *ifp)
{
const gchar *offset;
const gchar *type;
const gchar *value;
gboolean and = FALSE;
gboolean found = FALSE;
FileMatchType match_val;
while (magics_list)
{
if ((offset = magics_list->data) == NULL) break;
if ((magics_list = magics_list->next) == NULL) break;
if ((type = magics_list->data) == NULL) break;
if ((magics_list = magics_list->next) == NULL) break;
if ((value = magics_list->data) == NULL) break;
magics_list = magics_list->next;
match_val = file_check_single_magic (offset, type, value,
head, headsize,
ifp);
if (and)
found = found && (match_val != FILE_MATCH_NONE);
else
found = (match_val != FILE_MATCH_NONE);
and = (strchr (offset, '&') != NULL);
if (! and && found)
return match_val;
}
return FILE_MATCH_NONE;
}
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