9pfs: local: fix unlink of alien files in mapped-file mode

[mirror_qemu.git] / hw / 9pfs / 9p-local.c

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 0ca4c94ee4a8a19dbafa02e39203faf487053df9..7a0c383e7e8fdd26844ac8ebff6490267b849278 100644 (file)
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -957,39 +957,35 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
         int map_dirfd;
 
+        /* We need to remove the metadata as well:
+         * - the metadata directory if we're removing a directory
+         * - the metadata file in the parent's metadata directory
+         *
+         * If any of these are missing (ie, ENOENT) then we're probably
+         * trying to remove something that wasn't created in mapped-file
+         * mode. We just ignore the error.
+         */
         if (flags == AT_REMOVEDIR) {
             int fd;
 
-            fd = openat(dirfd, name, O_RDONLY | O_DIRECTORY | O_PATH);
+            fd = openat_dir(dirfd, name);
             if (fd == -1) {
                 goto err_out;
             }
-            /*
-             * If directory remove .virtfs_metadata contained in the
-             * directory
-             */
             ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
             close_preserve_errno(fd);
             if (ret < 0 && errno != ENOENT) {
-                /*
-                 * We didn't had the .virtfs_metadata file. May be file created
-                 * in non-mapped mode ?. Ignore ENOENT.
-                 */
                 goto err_out;
             }
         }
-        /*
-         * Now remove the name from parent directory
-         * .virtfs_metadata directory.
-         */
         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
-        ret = unlinkat(map_dirfd, name, 0);
-        close_preserve_errno(map_dirfd);
-        if (ret < 0 && errno != ENOENT) {
-            /*
-             * We didn't had the .virtfs_metadata file. May be file created
-             * in non-mapped mode ?. Ignore ENOENT.
-             */
+        if (map_dirfd != -1) {
+            ret = unlinkat(map_dirfd, name, 0);
+            close_preserve_errno(map_dirfd);
+            if (ret < 0 && errno != ENOENT) {
+                goto err_out;
+            }
+        } else if (errno != ENOENT) {
             goto err_out;
         }
     }
@@ -1098,8 +1094,13 @@ static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
 {
     if (dir_path) {
         v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
-    } else {
+    } else if (strcmp(name, "/")) {
         v9fs_path_sprintf(target, "%s", name);
+    } else {
+        /* We want the path of the export root to be relative, otherwise
+         * "*at()" syscalls would treat it as "/" in the host.
+         */
+        v9fs_path_sprintf(target, "%s", ".");
     }
     return 0;
 }