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// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later
#include <stdbool.h>
#include <string.h>
#include "drgn_internal.h"
#include "dwarf_constants.h"
#include "path.h"
#include "util.h"
bool path_iterator_next(struct path_iterator *it, const char **component_ret,
size_t *component_len_ret)
{
while (it->num_components) {
struct nstring *cur = &it->components[it->num_components - 1];
while (cur->len > 0) {
if (cur->str[cur->len - 1] == '/') {
if (cur->len == 1) {
/*
* This is an absolute path. Emit an
* empty component. Components joined
* before this one and remaining ".."
* components are not meaningful.
*/
it->num_components = 0;
it->dot_dot = 0;
*component_ret = "";
*component_len_ret = 0;
return true;
}
/* Skip redundant slashes. */
cur->len--;
continue;
}
size_t component_start = cur->len - 1;
while (component_start > 0 &&
cur->str[component_start - 1] != '/')
component_start--;
size_t component_len = cur->len - component_start;
cur->len = component_start;
if (component_len == 1 &&
cur->str[component_start] == '.') {
/* Skip "." components. */
} else if (component_len == 2 &&
cur->str[component_start] == '.' &&
cur->str[component_start + 1] == '.') {
/* Count ".." components. */
it->dot_dot++;
} else if (it->dot_dot) {
it->dot_dot--;
} else {
*component_ret = &cur->str[component_start];
*component_len_ret = component_len;
return true;
}
}
it->num_components--;
}
if (it->dot_dot) {
/*
* Leftover ".." components must be above the current
* directory.
*/
it->dot_dot--;
*component_ret = "..";
*component_len_ret = 2;
return true;
}
return false;
}
bool path_ends_with(struct path_iterator *haystack,
struct path_iterator *needle)
{
for (;;) {
const char *h_component, *n_component;
size_t h_component_len, n_component_len;
if (!path_iterator_next(needle, &n_component, &n_component_len))
return true;
if (!path_iterator_next(haystack, &h_component,
&h_component_len))
return false;
if (h_component_len != n_component_len ||
memcmp(h_component, n_component, h_component_len) != 0)
return false;
}
}
bool die_matches_filename(Dwarf_Die *die, const char *filename)
{
if (!filename || !filename[0])
return true;
struct nstring die_components[2];
struct path_iterator die_path = {
.components = die_components,
};
Dwarf_Die cu_die;
Dwarf_Attribute attr_mem, *attr;
attr = dwarf_attr_integrate(dwarf_diecu(die, &cu_die, NULL, NULL),
DW_AT_comp_dir, &attr_mem);
const char *path = dwarf_formstring(attr);
if (path) {
die_path.components[die_path.num_components].str = path;
die_path.components[die_path.num_components].len = strlen(path);
die_path.num_components++;
}
path = dwarf_decl_file(die);
if (!path)
return false;
/*
* If the declaration file name is absolute, the compilation directory
* component will be ignored.
*/
die_path.components[die_path.num_components].str = path;
die_path.components[die_path.num_components].len = strlen(path);
die_path.num_components++;
struct path_iterator needle = {
.components = (struct nstring []){
{ filename, strlen(filename) }
},
.num_components = 1,
};
return path_ends_with(&die_path, &needle);
}
LIBDRGN_PUBLIC bool drgn_filename_matches(const char *haystack,
const char *needle)
{
struct path_iterator haystack_path = {
.components = (struct nstring []){
{ haystack, strlen(haystack) }
},
.num_components = 1,
};
struct path_iterator needle_path = {
.components = (struct nstring []){
{ needle, strlen(needle) }
},
.num_components = 1,
};
return path_ends_with(&haystack_path, &needle_path);
}
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