vtest: add shm helpers

Right now, let's just support memfd. We could support other shared
memory types later.

vtest adaption based on following QEMU files:

    qemu/include/qemu/memfd.h
    qemu/util/memfd.c

v2: - memfd --> shm
    - don't call fcntl(fd, F_ADD_SEALS) because it fails under callgrind
      for some reason:

    ==8161== Warning: unimplemented fcntl command: 1033
    vtest_new_shm called fcntl which failed (-22)

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-By: Gert Wollny <gert.wollny@collabora.com>

vtest/Makefile.am

@@ -19,6 +19,8 @@ bin_PROGRAMS = virgl_test_server
 virgl_test_server_SOURCES =			\
 	util.c					\
 	util.h					\
+	vtest_shm.c				\
+	vtest_shm.h				\
 	vtest_server.c				\
 	vtest_renderer.c			\
 	vtest_protocol.h			\

vtest/vtest_shm.c

@@ -0,0 +1,78 @@
+/**************************************************************************
+ *
+ * Copyright (C) 2018 Chromium.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "util.h"
+#include "vtest_shm.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+static int memfd_create(const char *name, unsigned int flags)
+{
+#ifdef __NR_memfd_create
+    return syscall(__NR_memfd_create, name, flags);
+#else
+    return -1;
+#endif
+}
+
+int vtest_new_shm(uint32_t handle, size_t size)
+{
+   int fd, ret;
+   int length = snprintf(NULL, 0, "vtest-res-%u", handle);
+   char *str = malloc(length + 1);
+   snprintf(str, length + 1, "vtest-res-%u", handle);
+
+   fd = memfd_create(str, MFD_ALLOW_SEALING);
+   free(str);
+   if (fd < 0) {
+      return report_failed_call("memfd_create", -errno);
+   }
+
+   ret = ftruncate(fd, size);
+   if (ret < 0) {
+      close(fd);
+      return report_failed_call("ftruncate", -errno);
+   }
+
+   return fd;
+}
+
+int vtest_shm_check(void)
+{
+    int mfd = memfd_create("test", MFD_ALLOW_SEALING);
+
+    if (mfd >= 0) {
+        close(mfd);
+        return 1;
+    }
+
+    return 0;
+}
+

vtest/vtest_shm.h

@@ -0,0 +1,40 @@
+#ifndef VTEST_SHM_H
+#define VTEST_SHM_H
+
+#ifndef F_LINUX_SPECIFIC_BASE
+#define F_LINUX_SPECIFIC_BASE 1024
+#endif
+
+#ifndef F_ADD_SEALS
+#define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
+#define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
+
+#define F_SEAL_SEAL     0x0001  /* prevent further seals from being set */
+#define F_SEAL_SHRINK   0x0002  /* prevent file from shrinking */
+#define F_SEAL_GROW     0x0004  /* prevent file from growing */
+#define F_SEAL_WRITE    0x0008  /* prevent writes */
+#endif
+
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+
+#ifndef MFD_ALLOW_SEALING
+#define MFD_ALLOW_SEALING 0x0002U
+#endif
+
+#ifndef MFD_HUGETLB
+#define MFD_HUGETLB 0x0004U
+#endif
+
+#ifndef MFD_HUGE_SHIFT
+#define MFD_HUGE_SHIFT 26
+#endif
+
+#include <stdint.h>
+#include <string.h>
+
+int vtest_new_shm(uint32_t handle, size_t size);
+int vtest_shm_check(void);
+
+#endif /* VTEST_MEMFD_H */