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/*
lookup.c (02.09.09)
exFAT file system implementation library.
Free exFAT implementation.
Copyright (C) 2010-2015 Andrew Nayenko
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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "exfat.h"
#include <string.h>
#include <errno.h>
#include <inttypes.h>
int exfat_opendir(struct exfat* ef, struct exfat_node* dir,
struct exfat_iterator* it)
{
int rc;
exfat_get_node(dir);
it->parent = dir;
it->current = NULL;
rc = exfat_cache_directory(ef, dir);
if (rc != 0)
exfat_put_node(ef, dir);
return rc;
}
void exfat_closedir(struct exfat* ef, struct exfat_iterator* it)
{
exfat_put_node(ef, it->parent);
it->parent = NULL;
it->current = NULL;
}
struct exfat_node* exfat_readdir(struct exfat* ef, struct exfat_iterator* it)
{
if (it->current == NULL)
it->current = it->parent->child;
else
it->current = it->current->next;
if (it->current != NULL)
return exfat_get_node(it->current);
else
return NULL;
}
static int compare_char(struct exfat* ef, uint16_t a, uint16_t b)
{
if (a >= ef->upcase_chars || b >= ef->upcase_chars)
return (int) a - (int) b;
return (int) le16_to_cpu(ef->upcase[a]) - (int) le16_to_cpu(ef->upcase[b]);
}
static int compare_name(struct exfat* ef, const le16_t* a, const le16_t* b)
{
while (le16_to_cpu(*a) && le16_to_cpu(*b))
{
int rc = compare_char(ef, le16_to_cpu(*a), le16_to_cpu(*b));
if (rc != 0)
return rc;
a++;
b++;
}
return compare_char(ef, le16_to_cpu(*a), le16_to_cpu(*b));
}
static int lookup_name(struct exfat* ef, struct exfat_node* parent,
struct exfat_node** node, const char* name, size_t n)
{
struct exfat_iterator it;
le16_t buffer[EXFAT_NAME_MAX + 1];
int rc;
*node = NULL;
rc = utf8_to_utf16(buffer, name, EXFAT_NAME_MAX, n);
if (rc != 0)
return rc;
rc = exfat_opendir(ef, parent, &it);
if (rc != 0)
return rc;
while ((*node = exfat_readdir(ef, &it)))
{
if (compare_name(ef, buffer, (*node)->name) == 0)
{
exfat_closedir(ef, &it);
return 0;
}
exfat_put_node(ef, *node);
}
exfat_closedir(ef, &it);
return -ENOENT;
}
static size_t get_comp(const char* path, const char** comp)
{
const char* end;
*comp = path + strspn(path, "/"); /* skip leading slashes */
end = strchr(*comp, '/');
if (end == NULL)
return strlen(*comp);
else
return end - *comp;
}
int exfat_lookup(struct exfat* ef, struct exfat_node** node,
const char* path)
{
struct exfat_node* parent;
const char* p;
size_t n;
int rc;
/* start from the root directory */
parent = *node = exfat_get_node(ef->root);
for (p = path; (n = get_comp(p, &p)); p += n)
{
if (n == 1 && *p == '.') /* skip "." component */
continue;
rc = lookup_name(ef, parent, node, p, n);
if (rc != 0)
{
exfat_put_node(ef, parent);
return rc;
}
exfat_put_node(ef, parent);
parent = *node;
}
return 0;
}
static bool is_last_comp(const char* comp, size_t length)
{
const char* p = comp + length;
return get_comp(p, &p) == 0;
}
static bool is_allowed(const char* comp, size_t length)
{
size_t i;
for (i = 0; i < length; i++)
switch (comp[i])
{
case 0x01 ... 0x1f:
case '/':
case '\\':
case ':':
case '*':
case '?':
case '"':
case '<':
case '>':
case '|':
return false;
}
return true;
}
int exfat_split(struct exfat* ef, struct exfat_node** parent,
struct exfat_node** node, le16_t* name, const char* path)
{
const char* p;
size_t n;
int rc;
memset(name, 0, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
*parent = *node = exfat_get_node(ef->root);
for (p = path; (n = get_comp(p, &p)); p += n)
{
if (n == 1 && *p == '.')
continue;
if (is_last_comp(p, n))
{
if (!is_allowed(p, n))
{
/* contains characters that are not allowed */
exfat_put_node(ef, *parent);
return -ENOENT;
}
rc = utf8_to_utf16(name, p, EXFAT_NAME_MAX, n);
if (rc != 0)
{
exfat_put_node(ef, *parent);
return rc;
}
rc = lookup_name(ef, *parent, node, p, n);
if (rc != 0 && rc != -ENOENT)
{
exfat_put_node(ef, *parent);
return rc;
}
return 0;
}
rc = lookup_name(ef, *parent, node, p, n);
if (rc != 0)
{
exfat_put_node(ef, *parent);
return rc;
}
exfat_put_node(ef, *parent);
*parent = *node;
}
exfat_bug("impossible");
}
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