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basic/stat-util: add null_or_empty_path_with_root()

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2022-03-23 17:47:33 +01:00
parent 9825181143
commit 48542eac39
3 changed files with 39 additions and 6 deletions

View File

@ -127,17 +127,22 @@ bool null_or_empty(struct stat *st) {
return false;
}
int null_or_empty_path(const char *fn) {
int null_or_empty_path_with_root(const char *fn, const char *root) {
struct stat st;
int r;
assert(fn);
/* If we have the path, let's do an easy text comparison first. */
if (path_equal(fn, "/dev/null"))
/* A symlink to /dev/null or an empty file?
* When looking under root_dir, we can't expect /dev/ to be mounted,
* so let's see if the path is a (possibly dangling) symlink to /dev/null. */
if (path_equal_ptr(path_startswith(fn, root ?: "/"), "dev/null"))
return true;
if (stat(fn, &st) < 0)
return -errno;
r = chase_symlinks_and_stat(fn, root, CHASE_PREFIX_ROOT, NULL, &st, NULL);
if (r < 0)
return r;
return null_or_empty(&st);
}

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@ -31,9 +31,13 @@ static inline int dir_is_populated(const char *path) {
}
bool null_or_empty(struct stat *st) _pure_;
int null_or_empty_path(const char *fn);
int null_or_empty_path_with_root(const char *fn, const char *root);
int null_or_empty_fd(int fd);
static inline int null_or_empty_path(const char *fn) {
return null_or_empty_path_with_root(fn, NULL);
}
int path_is_read_only_fs(const char *path);
int files_same(const char *filea, const char *fileb, int flags);

View File

@ -18,6 +18,30 @@
#include "tests.h"
#include "tmpfile-util.h"
TEST(null_or_empty_path) {
assert_se(null_or_empty_path("/dev/null") == 1);
assert_se(null_or_empty_path("/dev/tty") == 1); /* We assume that any character device is "empty", bleh. */
assert_se(null_or_empty_path("../../../../../../../../../../../../../../../../../../../../dev/null") == 1);
assert_se(null_or_empty_path("/proc/self/exe") == 0);
assert_se(null_or_empty_path("/nosuchfileordir") == -ENOENT);
}
TEST(null_or_empty_path_with_root) {
assert_se(null_or_empty_path_with_root("/dev/null", NULL) == 1);
assert_se(null_or_empty_path_with_root("/dev/null", "/") == 1);
assert_se(null_or_empty_path_with_root("/dev/null", "/.././../") == 1);
assert_se(null_or_empty_path_with_root("/dev/null", "/.././..") == 1);
assert_se(null_or_empty_path_with_root("../../../../../../../../../../../../../../../../../../../../dev/null", NULL) == 1);
assert_se(null_or_empty_path_with_root("../../../../../../../../../../../../../../../../../../../../dev/null", "/") == 1);
assert_se(null_or_empty_path_with_root("/proc/self/exe", NULL) == 0);
assert_se(null_or_empty_path_with_root("/proc/self/exe", "/") == 0);
assert_se(null_or_empty_path_with_root("/nosuchfileordir", NULL) == -ENOENT);
assert_se(null_or_empty_path_with_root("/nosuchfileordir", "/.././../") == -ENOENT);
assert_se(null_or_empty_path_with_root("/nosuchfileordir", "/.././..") == -ENOENT);
assert_se(null_or_empty_path_with_root("/foobar/barbar/dev/null", "/foobar/barbar") == 1);
assert_se(null_or_empty_path_with_root("/foobar/barbar/dev/null", "/foobar/barbar/") == 1);
}
TEST(files_same) {
_cleanup_close_ int fd = -1;
char name[] = "/tmp/test-files_same.XXXXXX";