On Tue, Sep 29, 2015 at 06:34:36PM +0200, [email protected] wrote:
> From: Marc-André Lureau <[email protected]>
>
> Add an open/unlink/mmap fallback for system that do not support memfd.
> This patch may require additional SELinux policies to work for enforced
> systems, but should gracefully fail nonetheless.
>
> Signed-off-by: Marc-André Lureau <[email protected]>
I'd rather just fail migration.
> ---
> util/memfd.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/util/memfd.c b/util/memfd.c
> index 3168902..970b5b0 100644
> --- a/util/memfd.c
> +++ b/util/memfd.c
> @@ -84,8 +84,26 @@ void *qemu_memfd_alloc(const char *name, size_t size,
> unsigned int seals,
> return NULL;
> }
> } else {
> - perror("memfd");
> - return NULL;
> + const char *tmpdir = getenv("TMPDIR");
> + gchar *fname;
> +
> + tmpdir = tmpdir ? tmpdir : "/tmp";
> +
> + 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);
> --
> 2.4.3
