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#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <glib.h>
#include "bencode.h"
#include "trg-file-parser.h"
#define my_print_errno(x) printf("%s: error (%d) %s\n", __func__, errno, x);
static trg_torrent_file_node
*trg_torrent_file_node_insert(trg_torrent_file_node * top,
be_node * file_node, guint index,
gint64 * total_length)
{
int i;
trg_torrent_file_node *path_el_parent = top;
be_node *file_length_node = be_dict_find(file_node, "length", BE_INT);
be_node *file_path_node = be_dict_find(file_node, "path", BE_LIST);
if (!file_path_node || !file_length_node)
return NULL;
/* Iterate over the path list which contains each file/directory
* component of the path in order.
*/
for (i = 0;;) {
be_node *path_el_node = file_path_node->val.l[i];
trg_torrent_file_node *target_node = NULL;
GList *li;
/* Does this element exist already? */
for (li = path_el_parent->children; li != NULL;
li = g_list_next(li)) {
trg_torrent_file_node *x = (trg_torrent_file_node *) li->data;
if (!g_strcmp0(x->name, path_el_node->val.s)) {
target_node = x;
break;
}
}
if (!target_node) {
/* Create a new node and add it as a child of the parent from the
* last iteration. */
target_node = g_new0(trg_torrent_file_node, 1);
target_node->name = g_strdup(path_el_node->val.s);
path_el_parent->children =
g_list_append(path_el_parent->children, target_node);
}
path_el_parent = target_node;
/* Is this the last component of the path (the file)? */
if (!file_path_node->val.l[++i]) {
*total_length += (target_node->length =
(gint64) (file_length_node->val.i));
target_node->index = index;
return target_node;
}
}
}
static void trg_torrent_file_node_free(trg_torrent_file_node * node)
{
GList *li;
for (li = node->children; li != NULL; li = g_list_next(li))
trg_torrent_file_node_free((trg_torrent_file_node *) li->data);
g_list_free(node->children);
g_free(node->name);
g_free(node);
}
void trg_torrent_file_free(trg_torrent_file * t)
{
trg_torrent_file_node_free(t->top_node);
g_free(t->name);
g_free(t);
}
static trg_torrent_file_node *trg_parse_torrent_file_nodes(be_node *
info_node,
gint64 *
total_length)
{
be_node *files_node = be_dict_find(info_node, "files", BE_LIST);
trg_torrent_file_node *top_node = g_new0(trg_torrent_file_node, 1);
int i;
/* Probably means single file mode. */
if (!files_node)
return NULL;
for (i = 0; files_node->val.l[i]; ++i) {
be_node *file_node = files_node->val.l[i];
if (be_validate_node(file_node, BE_DICT) ||
!trg_torrent_file_node_insert(top_node, file_node, i,
total_length)) {
/* Unexpected format. Throw away everything, file indexes need to
* be correct. */
trg_torrent_file_node_free(top_node);
return NULL;
}
}
return top_node;
}
trg_torrent_file *trg_parse_torrent_file(char *filename)
{
int fd;
struct stat sb;
void *addr;
be_node *top_node, *info_node, *name_node;
trg_torrent_file *ret = NULL;
fd = open(filename, O_RDONLY);
if (fd < 0) {
my_print_errno("opening file");
return NULL;
}
if (fstat(fd, &sb) == -1) {
my_print_errno("on fstat");
close(fd);
return NULL;
}
addr = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == MAP_FAILED) {
my_print_errno("on mmap");
close(fd);
return NULL;
}
top_node = be_decoden((char *) addr, sb.st_size);
munmap(addr, sb.st_size);
close(fd);
if (!top_node) {
return NULL;
} else if (be_validate_node(top_node, BE_DICT)) {
goto out;
}
info_node = be_dict_find(top_node, "info", BE_DICT);
if (!info_node)
goto out;
name_node = be_dict_find(info_node, "name", BE_STR);
if (!name_node)
goto out;
ret = g_new0(trg_torrent_file, 1);
ret->name = g_strdup(name_node->val.s);
ret->top_node =
trg_parse_torrent_file_nodes(info_node, &(ret->total_length));
if (!ret->top_node) {
trg_torrent_file_node *file_node;
be_node *length_node = be_dict_find(info_node, "length", BE_INT);
if (!length_node) {
g_free(ret);
ret = NULL;
goto out;
}
file_node = g_new0(trg_torrent_file_node, 1);
file_node->length = ret->total_length =
(gint64) (length_node->val.i);
file_node->name = g_strdup(ret->name);
ret->top_node = file_node;
}
out:
be_free(top_node);
return ret;
}
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