util: add fallback for qemu_memfd_alloc()

[mirror_qemu.git] / util / memfd.c

diff --git a/util/memfd.c b/util/memfd.c
index c1194832bedf9caa38f6d13035ba2a3e53eaa40b..4b23765b4a75bd0f79c5c2ce4357fec136cf9b83 100644 (file)
--- a/util/memfd.c
+++ b/util/memfd.c
@@ -97,8 +97,24 @@ void *qemu_memfd_alloc(const char *name, size_t size, unsigned int seals,
             return NULL;
         }
     } else {
-        perror("memfd");
-        return NULL;
+        const char *tmpdir = g_get_tmp_dir();
+        gchar *fname;
+
+        fname = g_strdup_printf("%s/memfd-XXXXXX", tmpdir);
+        mfd = mkstemp(fname);
+        unlink(fname);
+        g_free(fname);
+
+        if (mfd == -1) {
+            perror("mkstemp");
+            return NULL;
+        }
+
+        if (ftruncate(mfd, size) == -1) {
+            perror("ftruncate");
+            close(mfd);
+            return NULL;
+        }
     }
 
     ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0);