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fs-util: add flags parameter to chase_symlinks() 

Let's remove chase_symlinks_prefix() and instead introduce a flags parameter to
chase_symlinks(), with a flag CHASE_PREFIX_ROOT that exposes the behaviour of
chase_symlinks_prefix().
This commit is contained in:
Lennart Poettering 2016-11-29 16:49:30 +01:00
parent a4eaf3cf82
commit c4f4fce79e
11 changed files with 45 additions and 48 deletions
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34
src/basic/fs-util.c
View File

@ -235,7 +235,7 @@ int readlink_and_canonicalize(const char *p, const char *root, char **ret) {
if (r < 0)
return r;
r = chase_symlinks(t, root, &s);
r = chase_symlinks(t, root, 0, &s);
if (r < 0)
/* If we can't follow up, then let's return the original string, slightly cleaned up. */
*ret = path_kill_slashes(t);
@ -598,7 +598,7 @@ int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
return r;
}
int chase_symlinks(const char *path, const char *_root, char **ret) {
int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) {
_cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
_cleanup_close_ int fd = -1;
unsigned max_follow = 32; /* how many symlinks to follow before giving up and returning ELOOP */
@ -611,8 +611,9 @@ int chase_symlinks(const char *path, const char *_root, char **ret) {
* symlinks relative to a root directory, instead of the root of the host.
*
* Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
* relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed
* shall *not* be prefixed by it.
* relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
* assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
* prefixed accordingly.
*
* Algorithmically this operates on two path buffers: "done" are the components of the path we already
* processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to
@ -629,16 +630,19 @@ int chase_symlinks(const char *path, const char *_root, char **ret) {
* Note: there's also chase_symlinks_prefix() (see below), which as first step prefixes the passed path by the
* passed root. */
if (original_root) {
r = path_make_absolute_cwd(original_root, &root);
if (r < 0)
return r;
if (flags & CHASE_PREFIX_ROOT)
path = prefix_roota(root, path);
}
r = path_make_absolute_cwd(path, &buffer);
if (r < 0)
return r;
if (_root) {
r = path_make_absolute_cwd(_root, &root);
if (r < 0)
return r;
}
fd = open("/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
if (fd < 0)
return -errno;
@ -791,13 +795,3 @@ int chase_symlinks(const char *path, const char *_root, char **ret) {
return 0;
}
int chase_symlinks_prefix(const char *path, const char *root, char **ret) {
const char *t;
/* Same as chase_symlinks(), but prefixes 'path' by 'root' first. */
t = prefix_roota(root, path);
return chase_symlinks(t, root, ret);
}

7
src/basic/fs-util.h
View File

@ -78,5 +78,8 @@ union inotify_event_buffer {
int inotify_add_watch_fd(int fd, int what, uint32_t mask);
int chase_symlinks(const char *path_with_prefix, const char *root, char **ret);
int chase_symlinks_prefix(const char *path_without_prefix, const char *root, char **ret);
enum {
CHASE_PREFIX_ROOT = 1, /* If set, the specified path will be prefixed by the specified root before beginning the iteration */
};
int chase_symlinks(const char *path_with_prefix, const char *root, unsigned flags, char **ret);

2
src/basic/mount-util.c
View File

@ -221,7 +221,7 @@ int path_is_mount_point(const char *t, const char *root, int flags) {
* /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
* look at needs to be /usr, not /. */
if (flags & AT_SYMLINK_FOLLOW) {
r = chase_symlinks(t, root, &canonical);
r = chase_symlinks(t, root, 0, &canonical);
if (r < 0)
return r;

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

@ -252,7 +252,7 @@ char **path_strv_resolve(char **l, const char *root) {
} else
t = *s;
r = chase_symlinks(t, root, &u);
r = chase_symlinks(t, root, 0, &u);
if (r == -ENOENT) {
if (root) {
u = orig;

2
src/core/namespace.c
View File

@ -665,7 +665,7 @@ static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned
_cleanup_free_ char *chased = NULL;
int k;
k = chase_symlinks(bind_mount_path(f), root_directory, &chased);
k = chase_symlinks(bind_mount_path(f), root_directory, 0, &chased);
if (k < 0) {
/* Get only real errors */
if (r >= 0 && (k != -ENOENT || !f->ignore))

6
src/delta/delta.c
View File

@ -89,11 +89,11 @@ static int equivalent(const char *a, const char *b) {
_cleanup_free_ char *x = NULL, *y = NULL;
int r;
r = chase_symlinks(a, NULL, &x);
r = chase_symlinks(a, NULL, 0, &x);
if (r < 0)
return r;
r = chase_symlinks(b, NULL, &y);
r = chase_symlinks(b, NULL, 0, &y);
if (r < 0)
return r;
@ -361,7 +361,7 @@ static int should_skip_prefix(const char* p) {
int r;
_cleanup_free_ char *target = NULL;
r = chase_symlinks(p, NULL, &target);
r = chase_symlinks(p, NULL, 0, &target);
if (r < 0)
return r;

2
src/journal/journalctl.c
View File

@ -941,7 +941,7 @@ static int add_matches(sd_journal *j, char **args) {
_cleanup_free_ char *p = NULL, *t = NULL, *t2 = NULL, *interpreter = NULL;
struct stat st;
r = chase_symlinks(*i, NULL, &p);
r = chase_symlinks(*i, NULL, 0, &p);
if (r < 0)
return log_error_errno(r, "Couldn't canonicalize path: %m");

6
src/nspawn/nspawn-mount.c
View File

@ -512,7 +512,7 @@ static int mount_bind(const char *dest, CustomMount *m) {
if (stat(m->source, &source_st) < 0)
return log_error_errno(errno, "Failed to stat %s: %m", m->source);
r = chase_symlinks_prefix(m->destination, dest, &where);
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT, &where);
if (r < 0)
return log_error_errno(r, "Failed to resolve %s: %m", m->destination);
@ -572,7 +572,7 @@ static int mount_tmpfs(
assert(dest);
assert(m);
r = chase_symlinks_prefix(m->destination, dest, &where);
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT, &where);
if (r < 0)
return log_error_errno(r, "Failed to resolve %s: %m", m->destination);
@ -612,7 +612,7 @@ static int mount_overlay(const char *dest, CustomMount *m) {
assert(dest);
assert(m);
r = chase_symlinks_prefix(m->destination, dest, &where);
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT, &where);
if (r < 0)
return log_error_errno(r, "Failed to resolve %s: %m", m->destination);

2
src/nspawn/nspawn.c
View File

@ -2675,7 +2675,7 @@ static int chase_symlinks_and_update(char **p) {
if (!*p)
return 0;
r = chase_symlinks(*p, NULL, &chased);
r = chase_symlinks(*p, NULL, 0, &chased);
if (r < 0)
return log_error_errno(r, "Failed to resolve path %s: %m", *p);

2
src/systemctl/systemctl.c
View File

@ -2487,7 +2487,7 @@ static int unit_file_find_path(LookupPaths *lp, const char *unit_name, char **un
if (!path)
return log_oom();
r = chase_symlinks(path, arg_root, &lpath);
r = chase_symlinks(path, arg_root, 0, &lpath);
if (r == -ENOENT)
continue;
if (r == -ENOMEM)

28
src/test/test-fs-util.c
View File

@ -62,18 +62,18 @@ static void test_chase_symlinks(void) {
/* Paths that use symlinks underneath the "root" */
r = chase_symlinks(p, NULL, &result);
r = chase_symlinks(p, NULL, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, "/usr"));
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r == -ENOENT);
q = strjoina(temp, "/usr");
assert_se(mkdir(q, 0700) >= 0);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, q));
@ -81,12 +81,12 @@ static void test_chase_symlinks(void) {
assert_se(symlink("/", p) >= 0);
result = mfree(result);
r = chase_symlinks(p, NULL, &result);
r = chase_symlinks(p, NULL, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, "/"));
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, temp));
@ -96,21 +96,21 @@ static void test_chase_symlinks(void) {
assert_se(symlink("../../..", p) >= 0);
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r == 0 && path_equal(result, temp));
p = strjoina(temp, "/6dotsusr");
assert_se(symlink("../../../usr", p) >= 0);
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r == 0 && path_equal(result, q));
p = strjoina(temp, "/top/8dotsusr");
assert_se(symlink("../../../../usr", p) >= 0);
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r == 0 && path_equal(result, q));
/* Paths that contain repeated slashes */
@ -119,28 +119,28 @@ static void test_chase_symlinks(void) {
assert_se(symlink("///usr///", p) >= 0);
result = mfree(result);
r = chase_symlinks(p, NULL, &result);
r = chase_symlinks(p, NULL, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, "/usr"));
result = mfree(result);
r = chase_symlinks(p, temp, &result);
r = chase_symlinks(p, temp, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, q));
/* Paths using . */
result = mfree(result);
r = chase_symlinks("/etc/./.././", NULL, &result);
r = chase_symlinks("/etc/./.././", NULL, 0, &result);
assert_se(r >= 0);
assert_se(path_equal(result, "/"));
result = mfree(result);
r = chase_symlinks("/etc/./.././", "/etc", &result);
r = chase_symlinks("/etc/./.././", "/etc", 0, &result);
assert_se(r == 0 && path_equal(result, "/etc"));
result = mfree(result);
r = chase_symlinks("/etc/machine-id/foo", NULL, &result);
r = chase_symlinks("/etc/machine-id/foo", NULL, 0, &result);
assert_se(r == -ENOTDIR);
/* Path that loops back to self */
@ -148,7 +148,7 @@ static void test_chase_symlinks(void) {
result = mfree(result);
p = strjoina(temp, "/recursive-symlink");
assert_se(symlink("recursive-symlink", p) >= 0);
r = chase_symlinks(p, NULL, &result);
r = chase_symlinks(p, NULL, 0, &result);
assert_se(r == -ELOOP);
assert_se(rm_rf(temp, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);