conf: fd-only operations in lxc_setup_dev_symlinks()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 0e17c93d77ddcae1a01f737f7fb73468d8442379..bfbc98a20559040d05f47f6de1fb2ec520b23381 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -781,31 +781,30 @@ static const struct dev_symlinks dev_symlinks[] = {
 
 static int lxc_setup_dev_symlinks(const struct lxc_rootfs *rootfs)
 {
-       int i, ret;
-       char path[PATH_MAX];
-       struct stat s;
-
-       for (i = 0; i < sizeof(dev_symlinks) / sizeof(dev_symlinks[0]); i++) {
+       for (int i = 0; i < sizeof(dev_symlinks) / sizeof(dev_symlinks[0]); i++) {
+               int ret;
+               struct stat s;
                const struct dev_symlinks *d = &dev_symlinks[i];
 
-               ret = snprintf(path, sizeof(path), "%s/dev/%s",
-                              rootfs->path ? rootfs->mount : "", d->name);
-               if (ret < 0 || (size_t)ret >= sizeof(path))
-                       return -1;
-
-               /* Stat the path first. If we don't get an error accept it as
+               /*
+                * Stat the path first. If we don't get an error accept it as
                 * is and don't try to create it
                 */
-               ret = stat(path, &s);
+               ret = fstatat(rootfs->dev_mntpt_fd, d->name, &s, 0);
                if (ret == 0)
                        continue;
 
-               ret = symlink(d->oldpath, path);
-               if (ret && errno != EEXIST) {
-                       if (errno == EROFS)
-                               WARN("Failed to create \"%s\". Read-only filesystem", path);
-                       else
-                               return log_error_errno(-1, errno, "Failed to create \"%s\"", path);
+               ret = symlinkat(d->oldpath, rootfs->dev_mntpt_fd, d->name);
+               if (ret) {
+                       switch (errno) {
+                       case EROFS:
+                               WARN("Failed to create \"%s\" on read-only filesystem", d->name);
+                               __fallthrough;
+                       case EEXIST:
+                               break;
+                       default:
+                               return log_error_errno(-errno, errno, "Failed to create \"%s\"", d->name);
+                       }
                }
        }