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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* hardlink.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "util/util.h"
#include "fstree.h"
#include <string.h>
#include <stdlib.h>
#include <errno.h>
static int resolve_link(fstree_t *fs, tree_node_t *node)
{
tree_node_t *start = node;
for (;;) {
if (node->mode == FSTREE_MODE_HARD_LINK_RESOLVED) {
node = node->data.target_node;
} else if (node->mode == FSTREE_MODE_HARD_LINK) {
node = fstree_get_node_by_path(fs, fs->root,
node->data.target,
false, false);
if (node == NULL)
return -1;
} else {
break;
}
if (node == start) {
errno = EMLINK;
return -1;
}
}
if (S_ISDIR(node->mode)) {
errno = EPERM;
return -1;
}
if (node->link_count == 0xFFFFFFFF) {
errno = EMLINK;
return -1;
}
start->mode = FSTREE_MODE_HARD_LINK_RESOLVED;
start->data.target_node = node;
node->link_count++;
return 0;
}
static int resolve_hard_links_dfs(fstree_t *fs, tree_node_t *n)
{
tree_node_t *it;
if (n->mode == FSTREE_MODE_HARD_LINK) {
if (resolve_link(fs, n))
goto fail_link;
} else if (S_ISDIR(n->mode)) {
for (it = n->data.dir.children; it != NULL; it = it->next) {
if (resolve_hard_links_dfs(fs, it))
return -1;
}
}
return 0;
fail_link: {
char *path = fstree_get_path(n);
fprintf(stderr, "Resolving hard link '%s' -> '%s': %s\n",
path == NULL ? n->name : path, n->data.target,
strerror(errno));
free(path);
}
return -1;
}
tree_node_t *fstree_add_hard_link(fstree_t *fs, const char *path,
const char *target)
{
struct stat sb;
tree_node_t *n;
memset(&sb, 0, sizeof(sb));
sb.st_mode = S_IFLNK | 0777;
n = fstree_add_generic(fs, path, &sb, target);
if (n != NULL) {
if (canonicalize_name(n->data.target)) {
free(n);
errno = EINVAL;
return NULL;
}
n->mode = FSTREE_MODE_HARD_LINK;
}
return n;
}
int fstree_resolve_hard_links(fstree_t *fs)
{
return resolve_hard_links_dfs(fs, fs->root);
}
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