Merge pull request #4879 from poettering/systemd

1 files changed, 29 insertions, 11 deletions

diff --git a/src/basic/stat-util.c b/src/basic/stat-util.c
index 309e84b93d..7e1914aa14 100644
--- a/src/basic/stat-util.c
+++ b/src/basic/stat-util.c
@@ -28,6 +28,7 @@
 
 #include "dirent-util.h"
 #include "fd-util.h"
+#include "fs-util.h"
 #include "macro.h"
 #include "missing.h"
 #include "stat-util.h"
@@ -143,22 +144,29 @@ int path_is_read_only_fs(const char *path) {
 }
 
 int path_is_os_tree(const char *path) {
-        char *p;
         int r;
 
         assert(path);
 
-        /* We use /usr/lib/os-release as flag file if something is an OS */
-        p = strjoina(path, "/usr/lib/os-release");
-        r = access(p, F_OK);
-        if (r >= 0)
-                return 1;
+        /* Does the path exist at all? If not, generate an error immediately. This is useful so that a missing root dir
+         * always results in -ENOENT, and we can properly distuingish the case where the whole root doesn't exist from
+         * the case where just the os-release file is missing. */
+        if (laccess(path, F_OK) < 0)
+                return -errno;
 
-        /* Also check for the old location in /etc, just in case. */
-        p = strjoina(path, "/etc/os-release");
-        r = access(p, F_OK);
+        /* We use /usr/lib/os-release as flag file if something is an OS */
+        r = chase_symlinks("/usr/lib/os-release", path, CHASE_PREFIX_ROOT, NULL);
+        if (r == -ENOENT) {
+
+                /* Also check for the old location in /etc, just in case. */
+                r = chase_symlinks("/etc/os-release", path, CHASE_PREFIX_ROOT, NULL);
+                if (r == -ENOENT)
+                        return 0; /* We got nothing */
+        }
+        if (r < 0)
+                return r;
 
-        return r >= 0;
+        return 1;
 }
 
 int files_same(const char *filea, const char *fileb) {
@@ -196,7 +204,7 @@ int fd_check_fstype(int fd, statfs_f_type_t magic_value) {
 int path_check_fstype(const char *path, statfs_f_type_t magic_value) {
         _cleanup_close_ int fd = -1;
 
-        fd = open(path, O_RDONLY);
+        fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
         if (fd < 0)
                 return -errno;
 
@@ -216,3 +224,13 @@ int fd_is_temporary_fs(int fd) {
 
         return is_temporary_fs(&s);
 }
+
+int path_is_temporary_fs(const char *path) {
+        _cleanup_close_ int fd = -1;
+
+        fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
+        if (fd < 0)
+                return -errno;
+
+        return fd_is_temporary_fs(fd);
+}