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path-util: use path_find_first_component() in path_make_relative()

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This also makes the function checks the result is a valid path or not.
This commit is contained in:
Yu Watanabe 2021-05-02 05:53:14 +09:00
parent 63f11e354a
commit fe69c41ee8
3 changed files with 87 additions and 81 deletions
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125
src/basic/path-util.c
View File

@ -107,93 +107,96 @@ int path_make_absolute_cwd(const char *p, char **ret) {
return 0;
}
int path_make_relative(const char *from_dir, const char *to_path, char **_r) {
char *f, *t, *r, *p;
unsigned n_parents = 0;
int path_make_relative(const char *from, const char *to, char **ret) {
_cleanup_free_ char *result = NULL;
unsigned n_parents;
const char *f, *t;
int r, k;
char *p;
assert(from_dir);
assert(to_path);
assert(_r);
assert(from);
assert(to);
assert(ret);
/* Strips the common part, and adds ".." elements as necessary. */
if (!path_is_absolute(from_dir) || !path_is_absolute(to_path))
if (!path_is_absolute(from) || !path_is_absolute(to))
return -EINVAL;
f = strdupa(from_dir);
t = strdupa(to_path);
path_simplify(f, true);
path_simplify(t, true);
/* Skip the common part. */
for (;;) {
size_t a, b;
r = path_find_first_component(&from, true, &f);
if (r < 0)
return r;
f += *f == '/';
t += *t == '/';
k = path_find_first_component(&to, true, &t);
if (k < 0)
return k;
if (!*f) {
if (!*t)
/* from_dir equals to_path. */
r = strdup(".");
else
/* from_dir is a parent directory of to_path. */
r = strdup(t);
if (!r)
return -ENOMEM;
if (r == 0) {
/* end of 'from' */
if (k == 0) {
/* from and to are equivalent. */
result = strdup(".");
if (!result)
return -ENOMEM;
} else {
/* 'to' is inside of 'from'. */
result = strdup(t);
if (!result)
return -ENOMEM;
*_r = r;
path_simplify(result, true);
if (!path_is_valid(result))
return -EINVAL;
}
*ret = TAKE_PTR(result);
return 0;
}
if (!*t)
if (r != k || !strneq(f, t, r))
break;
a = strcspn(f, "/");
b = strcspn(t, "/");
if (a != b || memcmp(f, t, a) != 0)
break;
f += a;
t += b;
}
/* If we're here, then "from_dir" has one or more elements that need to
* be replaced with "..". */
/* Count the number of necessary ".." elements. */
for (; *f;) {
size_t w;
w = strcspn(f, "/");
/* If this includes ".." we can't do a simple series of "..", refuse */
if (w == 2 && f[0] == '.' && f[1] == '.')
return -EINVAL;
/* Count number of elements */
n_parents++;
f += w;
f += *f == '/';
for (n_parents = 1;; n_parents++) {
/* If this includes ".." we can't do a simple series of "..". */
r = path_find_first_component(&from, false, &f);
if (r < 0)
return r;
if (r == 0)
break;
}
r = new(char, n_parents * 3 + strlen(t) + 1);
if (!r)
if (isempty(t) && n_parents * 3 > PATH_MAX)
/* PATH_MAX is counted *with* the trailing NUL byte */
return -EINVAL;
result = new(char, n_parents * 3 + !isempty(t) + strlen_ptr(t));
if (!result)
return -ENOMEM;
for (p = r; n_parents > 0; n_parents--)
for (p = result; n_parents > 0; n_parents--)
p = mempcpy(p, "../", 3);
if (*t)
strcpy(p, t);
else
/* Remove trailing slash */
*(--p) = 0;
if (isempty(t)) {
/* Remove trailing slash and terminate string. */
*(--p) = '\0';
*ret = TAKE_PTR(result);
return 0;
}
*_r = r;
strcpy(p, t);
path_simplify(result, true);
if (!path_is_valid(result))
return -EINVAL;
*ret = TAKE_PTR(result);
return 0;
}

2
src/basic/path-util.h
View File

@ -56,7 +56,7 @@ int path_split_and_make_absolute(const char *p, char ***ret);
char* path_make_absolute(const char *p, const char *prefix);
int safe_getcwd(char **ret);
int path_make_absolute_cwd(const char *p, char **ret);
int path_make_relative(const char *from_dir, const char *to_path, char **_r);
int path_make_relative(const char *from, const char *to, char **ret);
char *path_startswith_full(const char *path, const char *prefix, bool accept_dot_dot) _pure_;
static inline char* path_startswith(const char *path, const char *prefix) {
return path_startswith_full(path, prefix, true);

41
src/test/test-path-util.c
View File

@ -420,29 +420,32 @@ static void test_fsck_exists(void) {
assert_se(fsck_exists("/../bin/") == 0);
}
static void test_make_relative(void) {
char *result;
static void test_path_make_relative_one(const char *from, const char *to, const char *expected) {
_cleanup_free_ char *z = NULL;
int r;
log_info("/* %s(%s, %s) */", __func__, from, to);
r = path_make_relative(from, to, &z);
assert_se((r >= 0) == !!expected);
assert_se(streq_ptr(z, expected));
}
static void test_make_relative(void) {
log_info("/* %s */", __func__);
assert_se(path_make_relative("some/relative/path", "/some/path", &result) < 0);
assert_se(path_make_relative("/some/path", "some/relative/path", &result) < 0);
assert_se(path_make_relative("/some/dotdot/../path", "/some/path", &result) < 0);
test_path_make_relative_one("some/relative/path", "/some/path", NULL);
test_path_make_relative_one("/some/path", "some/relative/path", NULL);
test_path_make_relative_one("/some/dotdot/../path", "/some/path", NULL);
#define test(from_dir, to_path, expected) { \
_cleanup_free_ char *z = NULL; \
path_make_relative(from_dir, to_path, &z); \
assert_se(streq(z, expected)); \
}
test("/", "/", ".");
test("/", "/some/path", "some/path");
test("/some/path", "/some/path", ".");
test("/some/path", "/some/path/in/subdir", "in/subdir");
test("/some/path", "/", "../..");
test("/some/path", "/some/other/path", "../other/path");
test("/some/path/./dot", "/some/further/path", "../../further/path");
test("//extra.//.//./.slashes//./won't////fo.ol///anybody//", "/././/extra././/.slashes////ar.e/.just/././.fine///", "../../../ar.e/.just/.fine");
test_path_make_relative_one("/", "/", ".");
test_path_make_relative_one("/", "/some/path", "some/path");
test_path_make_relative_one("/some/path", "/some/path", ".");
test_path_make_relative_one("/some/path", "/some/path/in/subdir", "in/subdir");
test_path_make_relative_one("/some/path", "/", "../..");
test_path_make_relative_one("/some/path", "/some/other/path", "../other/path");
test_path_make_relative_one("/some/path/./dot", "/some/further/path", "../../further/path");
test_path_make_relative_one("//extra.//.//./.slashes//./won't////fo.ol///anybody//", "/././/extra././/.slashes////ar.e/.just/././.fine///", "../../../ar.e/.just/.fine");
}
static void test_strv_resolve(void) {