fstools: check existing filesystem state before writing the new one

[project/fstools.git] / libfstools / overlay.c

diff --git a/libfstools/overlay.c b/libfstools/overlay.c
index 0677c34ed3588bbc32a52c72c446ac4cd84f9626..cdac23e0d04bb6c707d9ca873085936a9749c545 100644 (file)
--- a/libfstools/overlay.c
+++ b/libfstools/overlay.c
@@ -14,7 +14,6 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/mount.h>
-#include <sys/syscall.h>
 
 #include <asm/byteorder.h>
 
@@ -35,18 +34,6 @@
 
 static bool keep_sysupgrade;
 
-static ssize_t
-fs_getxattr(const char *path, const char *name, void *value, size_t size)
-{
-       return syscall(__NR_getxattr, path, name, value, size);
-}
-
-static ssize_t
-fs_setxattr(const char *path, const char *name, const void *value, size_t size, int flags)
-{
-       return syscall(__NR_setxattr, path, name, value, size, flags);
-}
-
 static int
 handle_rmdir(const char *dir)
 {
@@ -80,6 +67,7 @@ handle_rmdir(const char *dir)
 void
 foreachdir(const char *dir, int (*cb)(const char*))
 {
+       struct stat s = { 0 };
        char globdir[256];
        glob_t gl;
        int j;
@@ -90,9 +78,16 @@ foreachdir(const char *dir, int (*cb)(const char*))
                snprintf(globdir, 256, "%s/*", dir); /**/
 
        if (!glob(globdir, GLOB_NOESCAPE | GLOB_MARK | GLOB_ONLYDIR, NULL, &gl))
-               for (j = 0; j < gl.gl_pathc; j++)
-                       foreachdir(gl.gl_pathv[j], cb);
+               for (j = 0; j < gl.gl_pathc; j++) {
+                       char *dir = gl.gl_pathv[j];
+                       int len = strlen(gl.gl_pathv[j]);
 
+                       if (len > 1 && dir[len - 1] == '/')
+                               dir[len - 1] = '\0';
+
+                       if (!lstat(gl.gl_pathv[j], &s) && !S_ISLNK(s.st_mode))
+                               foreachdir(gl.gl_pathv[j], cb);
+       }
        cb(dir);
 }
 
@@ -290,11 +285,20 @@ static int overlay_mount_fs(struct volume *v)
 
 enum fs_state fs_state_get(const char *dir)
 {
+       char *path;
+       char valstr[16];
        uint32_t val;
+       ssize_t len;
 
-       if (fs_getxattr(dir, "user.fs_state", &val, sizeof(val)) != sizeof(val))
+       path = alloca(strlen(dir) + 1 + sizeof("/.fs_state"));
+       sprintf(path, "%s/.fs_state", dir);
+       len = readlink(path, valstr, sizeof(valstr) - 1);
+       if (len < 0)
                return FS_STATE_UNKNOWN;
 
+       valstr[len] = 0;
+       val = atoi(valstr);
+
        if (val > __FS_STATE_LAST)
                return FS_STATE_UNKNOWN;
 
@@ -304,9 +308,18 @@ enum fs_state fs_state_get(const char *dir)
 
 int fs_state_set(const char *dir, enum fs_state state)
 {
-       uint32_t val = state;
+       char valstr[16];
+       char *path;
+
+       if (fs_state_get(dir) == state)
+               return 0;
+
+       path = alloca(strlen(dir) + 1 + sizeof("/.fs_state"));
+       sprintf(path, "%s/.fs_state", dir);
+       unlink(path);
+       snprintf(valstr, sizeof(valstr), "%d", state);
 
-       return fs_setxattr(dir, "user.fs_state", &val, sizeof(val), 0);
+       return symlink(valstr, path);
 }