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Re: [Qemu-devel] [PATCH v6 06/24] memfd: add fallback for memfd
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v6 06/24] memfd: add fallback for memfd |
Date: |
Wed, 30 Sep 2015 12:03:42 +0300 |
On Tue, Sep 29, 2015 at 06:34:36PM +0200, address@hidden wrote:
> From: Marc-André Lureau <address@hidden>
>
> 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 <address@hidden>
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
- [Qemu-devel] [PATCH v6 00/24] vhost-user: add migration support, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 08/24] vhost: add vhost_set_log_base op, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 09/24] vhost-user: add vhost_user_requires_shm_log(), marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 11/24] vhost-user: send log shm fd along with log_base, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 14/24] vhost-user: document migration log, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 15/24] net: add trace_vhost_user_event, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 13/24] vhost: use a function for each call, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 06/24] memfd: add fallback for memfd, marcandre . lureau, 2015/10/08
- Re: [Qemu-devel] [PATCH v6 06/24] memfd: add fallback for memfd,
Michael S. Tsirkin <=
- [Qemu-devel] [PATCH v6 16/24] vhost user: add support of live migration, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 23/24] vhost-user-test: check ownership during migration, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 22/24] vhost-user-test: add live-migration test, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 24/24] vhost-user: use an enum helper for features mask, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 01/24] vhost-user: unit test for new messages, marcandre . lureau, 2015/10/08
- [Qemu-devel] [PATCH v6 04/24] util: add linux-only memfd fallback, marcandre . lureau, 2015/10/08