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Re: [PATCH v3 07/11] softmmu/physmem: Never return directories from file
From: |
Peter Xu |
Subject: |
Re: [PATCH v3 07/11] softmmu/physmem: Never return directories from file_ram_open() |
Date: |
Wed, 23 Aug 2023 16:22:16 -0400 |
On Wed, Aug 23, 2023 at 05:34:07PM +0200, David Hildenbrand wrote:
> open() does not fail on directories when opening them readonly (O_RDONLY).
>
> Currently, we succeed opening such directories and fail later during
> mmap(), resulting in a misleading error message.
>
> $ ./qemu-system-x86_64 \
> -object memory-backend-file,id=ram0,mem-path=tmp,readonly=true,size=1g
> qemu-system-x86_64: unable to map backing store for guest RAM: No such device
>
> To identify directories and handle them accordingly in file_ram_open()
> also when readonly=true was specified, detect if we just opened a directory
> using fstat() instead. Then, fail file_ram_open() right away, similarly
> to how we now fail if the file does not exist and we want to open the
> file readonly.
>
> With this change, we get a nicer error message:
> qemu-system-x86_64: can't open backing store tmp for guest RAM: Is a
> directory
>
> Note that the only memory-backend-file will end up calling
> memory_region_init_ram_from_file() -> qemu_ram_alloc_from_file() ->
> file_ram_open().
>
> Reported-by: Thiner Logoer <logoerthiner1@163.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
- Re:[PATCH v3 11/11] machine: Improve error message when using default RAM backend id, (continued)
- Re:[PATCH v3 11/11] machine: Improve error message when using default RAM backend id, ThinerLogoer, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, David Hildenbrand, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, Markus Armbruster, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, David Hildenbrand, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, Markus Armbruster, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, David Hildenbrand, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, David Hildenbrand, 2023/08/25
- Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, Philippe Mathieu-Daudé, 2023/08/29
Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id, Mario Casquero, 2023/08/29
[PATCH v3 07/11] softmmu/physmem: Never return directories from file_ram_open(), David Hildenbrand, 2023/08/23
- Re: [PATCH v3 07/11] softmmu/physmem: Never return directories from file_ram_open(),
Peter Xu <=
[PATCH v3 09/11] docs: Start documenting VM templating, David Hildenbrand, 2023/08/23
[PATCH v3 08/11] docs: Don't mention "-mem-path" in multi-process.rst, David Hildenbrand, 2023/08/23
[PATCH v3 06/11] softmmu/physmem: Fail creation of new files in file_ram_open() with readonly=true, David Hildenbrand, 2023/08/23