From 321384507f1223033fc0fb2969f6e29598ba7d92 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 2 Feb 2017 00:06:18 +0100
Subject: [PATCH] fs-util: unify code we use to check if dirent's d_name is "."
 or ".."

We use different idioms at different places. Let's replace this is the
one true new idiom, that is even a bit faster...
---
 src/basic/cgroup-util.c |  3 +--
 src/basic/copy.c        |  2 +-
 src/basic/path-util.c   | 25 +++++++++++++++++++------
 src/basic/path-util.h   |  2 ++
 src/basic/rm-rf.c       |  2 +-
 src/basic/socket-util.c |  2 +-
 src/shared/clean-ipc.c  |  4 ++--
 7 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 0e2f2cbc0..32cf4298f 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -184,8 +184,7 @@ int cg_read_subgroup(DIR *d, char **fn) {
                 if (de->d_type != DT_DIR)
                         continue;
 
-                if (streq(de->d_name, ".") ||
-                    streq(de->d_name, ".."))
+                if (dot_or_dot_dot(de->d_name))
                         continue;
 
                 b = strdup(de->d_name);
diff --git a/src/basic/copy.c b/src/basic/copy.c
index 4e5f392fe..20078a81e 100644
--- a/src/basic/copy.c
+++ b/src/basic/copy.c
@@ -333,7 +333,7 @@ static int fd_copy_directory(
                 struct stat buf;
                 int q;
 
-                if (STR_IN_SET(de->d_name, ".", ".."))
+                if (dot_or_dot_dot(de->d_name))
                         continue;
 
                 if (fstatat(dirfd(d), de->d_name, &buf, AT_SYMLINK_NOFOLLOW) < 0) {
diff --git a/src/basic/path-util.c b/src/basic/path-util.c
index 84f327d7d..05384c26b 100644
--- a/src/basic/path-util.c
+++ b/src/basic/path-util.c
@@ -703,10 +703,7 @@ bool filename_is_valid(const char *p) {
         if (isempty(p))
                 return false;
 
-        if (streq(p, "."))
-                return false;
-
-        if (streq(p, ".."))
+        if (dot_or_dot_dot(p))
                 return false;
 
         e = strchrnul(p, '/');
@@ -724,14 +721,17 @@ bool path_is_safe(const char *p) {
         if (isempty(p))
                 return false;
 
-        if (streq(p, "..") || startswith(p, "../") || endswith(p, "/..") || strstr(p, "/../"))
+        if (dot_or_dot_dot(p))
+                return false;
+
+        if (startswith(p, "../") || endswith(p, "/..") || strstr(p, "/../"))
                 return false;
 
         if (strlen(p)+1 > PATH_MAX)
                 return false;
 
         /* The following two checks are not really dangerous, but hey, they still are confusing */
-        if (streq(p, ".") || startswith(p, "./") || endswith(p, "/.") || strstr(p, "/./"))
+        if (startswith(p, "./") || endswith(p, "/.") || strstr(p, "/./"))
                 return false;
 
         if (strstr(p, "//"))
@@ -898,3 +898,16 @@ int systemd_installation_has_version(const char *root, unsigned minimal_version)
         return false;
 }
 #endif // 0
+
+bool dot_or_dot_dot(const char *path) {
+        if (!path)
+                return false;
+        if (path[0] != '.')
+                return false;
+        if (path[1] == 0)
+                return true;
+        if (path[1] != '.')
+                return false;
+
+        return path[2] == 0;
+}
diff --git a/src/basic/path-util.h b/src/basic/path-util.h
index 6c906e54a..3e1519efe 100644
--- a/src/basic/path-util.h
+++ b/src/basic/path-util.h
@@ -157,3 +157,5 @@ bool is_deviceallow_pattern(const char *path);
 
 int systemd_installation_has_version(const char *root, unsigned minimal_version);
 #endif // 0
+
+bool dot_or_dot_dot(const char *path);
diff --git a/src/basic/rm-rf.c b/src/basic/rm-rf.c
index a90359194..85854acf9 100644
--- a/src/basic/rm-rf.c
+++ b/src/basic/rm-rf.c
@@ -82,7 +82,7 @@ int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
                 bool is_dir;
                 struct stat st;
 
-                if (streq(de->d_name, ".") || streq(de->d_name, ".."))
+                if (dot_or_dot_dot(de->d_name))
                         continue;
 
                 if (de->d_type == DT_UNKNOWN ||
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 6a8ca1d7e..9ec901261 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -881,7 +881,7 @@ bool ifname_valid(const char *p) {
         if (strlen(p) >= IFNAMSIZ)
                 return false;
 
-        if (STR_IN_SET(p, ".", ".."))
+        if (dot_or_dot_dot(p))
                 return false;
 
         while (*p) {
diff --git a/src/shared/clean-ipc.c b/src/shared/clean-ipc.c
index ba48fb0ec..3b4231827 100644
--- a/src/shared/clean-ipc.c
+++ b/src/shared/clean-ipc.c
@@ -225,7 +225,7 @@ static int clean_posix_shm_internal(DIR *dir, uid_t uid, gid_t gid) {
         FOREACH_DIRENT_ALL(de, dir, goto fail) {
                 struct stat st;
 
-                if (STR_IN_SET(de->d_name, "..", "."))
+                if (dot_or_dot_dot(de->d_name))
                         continue;
 
                 if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
@@ -311,7 +311,7 @@ static int clean_posix_mq(uid_t uid, gid_t gid) {
                 struct stat st;
                 char fn[1+strlen(de->d_name)+1];
 
-                if (STR_IN_SET(de->d_name, "..", "."))
+                if (dot_or_dot_dot(de->d_name))
                         continue;
 
                 if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
-- 
2.30.2