[Bug 1913012] Re: Installed firmware descriptor files contain (invalid) relative paths

[Alain Kalker]

There is an issue on Void Linux packages issue tracker about this bug[1]

# Steps to verify the issue on a fresh Git clone of QEMU source

$ git clone https://github.com/qemu/qemu
$ cd qemu
$ make DEBUG=1 docker-test-misc@alpine
[...]
  COPY    RUNNER
    RUN test-misc in qemu/alpine 
* Prepared to run command:
  ./test-misc
* Hit Ctrl-D to continue, or type 'exit 1' to abort

bash-5.1$ . common-rc
[...]
bash-5.1$ configure_qemu --disable-system --disable-user
Configure options:
--enable-werror --prefix=/tmp/qemu-test/install --disable-system --disable-user
cross containers  no
The Meson build system
Version: 0.56.2
Source dir: /tmp/qemu-test/src
Build dir: /tmp/qemu-test/src/tests/docker
Build type: native build
Project name: qemu
Project version: 5.2.50
[...]
bash-5.1$ grep filename pc-bios/descriptors/*
pc-bios/descriptors/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-secure-code.fd",
pc-bios/descriptors/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",
[...all other matches have relative paths...]
bash-5.1$ exit 1
[...]

# Research

The filename path substitution appears to be done in the file 
`pc-bios/descriptors/meson.build`.
In particular, occurrences of `@DATADIR@` in the template files get substituted 
using the value of `qemu_datadir`:

  configure_file(input: files(f),                                               
                 output: f,                                                     
                 configuration: {'DATADIR': qemu_datadir},                      
                 install: get_option('install_blobs'),                          
                 install_dir: qemu_datadir / 'firmware')

The variable `qemu_datadir` gets initialized from toplevel `meson.build`
file using:

   qemu_datadir = get_option('datadir') / get_option('qemu_suffix')

>From the Meson documentation on built-in (build) options[2], `datadir`
option gets initialized to `"share"` (note: a relative path!) by
default, unless `datadir` build option is configured explicitly, so the
value of `qemu_datadir`, as well as the substitution made ends up being
a relative path as well.

I found a commit which I think is relevant to why this choice was
made[3].

# Test a workaround, try #1: specify `datadir` manually

$ make DEBUG=1 docker-test-misc@alpine
[...]
bash-5.1$ configure_qemu --datadir=/usr/share --disable-system --disable-user
Configure options:
--enable-werror --prefix=/tmp/qemu-test/install --datadir=/usr/share 
--disable-system --disable-user
cross containers  no
The Meson build system
Version: 0.56.2
Source dir: /tmp/qemu-test/src
Build dir: /tmp/qemu-test/src/tests/docker
Build type: native build

../../meson.build:1:0: ERROR: The value of the 'datadir' option is '/usr/share' 
which must be a subdir of the prefix '/tmp/qemu-test/install'.
Note that if you pass a relative path, it is assumed to be a subdir of prefix.

A full log can be found at /tmp/qemu-test/src/tests/docker/meson-logs
/meson-log.txt

ERROR: meson setup failed

Ah! So perhaps `datadir` can be an absolute path, but then it must be a subdir 
of the (already specified) `prefix`.
Let's try again.

# Test a workaround, try #2: specify `datadir` as subdir of <prefix>
manually

$ make DEBUG=1 docker-test-misc@alpine
[...]
bash-5.1$ configure_qemu --datadir=/tmp/qemu-test/install/share 
--disable-system --disable-user
Configure options:
--enable-werror --prefix=/tmp/qemu-test/install 
--datadir=/tmp/qemu-test/install/share --disable-system --disable-user
[...]
bash-5.1$ grep filename pc-bios/descriptors/*
pc-bios/descriptors/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-secure-code.fd",
pc-bios/descriptors/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",
bash-5.1$ exit 1

Getting there, but the paths are still relative, missing the initial
`/`.

[1]: https://github.com/void-linux/void-packages/issues/27965
[2]: https://mesonbuild.com/Builtin-options.html
[3]: 
https://github.com/qemu/qemu/commit/ab4c0996f80d43d1fc28c6e76f4ecb27423a7e29


** Bug watch added: github.com/void-linux/void-packages/issues #27965
   https://github.com/void-linux/void-packages/issues/27965

** Description changed:

- Unless the Qemu build is configured using `./configure --datadir=<path>
- where <path> is some absolute path which is a subdirectory of <prefix>,
- the resulting installed firmware descriptor files contain relative paths
- for their `mapping.filename` properties. These relative paths will not
- be accepted as valid by tools like `virt-install`, resulting in the
- inability to configure new VMs using these firmware descriptors.
+ After building and installing QEMU, the resulting installed firmware
+ descriptor files contain relative paths for their `mapping.filename`
+ properties. These relative paths will not be accepted as valid by tools
+ like `virt-install`, resulting in the inability to configure new VMs
+ which reference these firmware descriptors.
  
  # QEMU version
  $ qemu-system-x86_64 -version
  QEMU emulator version 5.2.0
  
  (I've also reproduced the issue with QEMU built from Git master @
  v5.2.0-1300-g0e32462630, see next comment.)
  
  # OS version
  Void Linux x86_64 (glibc)
  
  Steps to reproduce (with results on my system):
  
  # Verify the symptom
  
  $ virt-install --boot firmware=efi --disk none --memory 2048
  Using default --name vm4
  WARNING  No operating system detected, VM performance may suffer. Specify an 
OS with --os-variant for optimal results.
  
  Starting install...
  ERROR    Failed to open file 'share/qemu/edk2-i386-vars.fd': No such file or 
directory
  Domain installation does not appear to have been successful.
  If it was, you can restart your domain by running:
-   virsh --connect qemu:///session start vm4
+   virsh --connect qemu:///session start vm4
  otherwise, please restart your installation.
  
  # Verify most likely cause
  
- $ grep filename /usr/share/qemu/firmware/*i386*.json 
+ $ grep filename /usr/share/qemu/firmware/*i386*.json
  /usr/share/qemu/firmware/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-secure-code.fd",
  /usr/share/qemu/firmware/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",
  /usr/share/qemu/firmware/60-edk2-i386.json:            "filename": 
"share/qemu/edk2-i386-code.fd",
  /usr/share/qemu/firmware/60-edk2-i386.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",

-- 
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https://bugs.launchpad.net/bugs/1913012

Title:
  Installed firmware descriptor files contain (invalid) relative paths

Status in QEMU:
  New

Bug description:
  After building and installing QEMU, the resulting installed firmware
  descriptor files contain relative paths for their `mapping.filename`
  properties. These relative paths will not be accepted as valid by
  tools like `virt-install`, resulting in the inability to configure new
  VMs which reference these firmware descriptors.

  # QEMU version
  $ qemu-system-x86_64 -version
  QEMU emulator version 5.2.0

  (I've also reproduced the issue with QEMU built from Git master @
  v5.2.0-1300-g0e32462630, see next comment.)

  # OS version
  Void Linux x86_64 (glibc)

  Steps to reproduce (with results on my system):

  # Verify the symptom

  $ virt-install --boot firmware=efi --disk none --memory 2048
  Using default --name vm4
  WARNING  No operating system detected, VM performance may suffer. Specify an 
OS with --os-variant for optimal results.

  Starting install...
  ERROR    Failed to open file 'share/qemu/edk2-i386-vars.fd': No such file or 
directory
  Domain installation does not appear to have been successful.
  If it was, you can restart your domain by running:
    virsh --connect qemu:///session start vm4
  otherwise, please restart your installation.

  # Verify most likely cause

  $ grep filename /usr/share/qemu/firmware/*i386*.json
  /usr/share/qemu/firmware/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-secure-code.fd",
  /usr/share/qemu/firmware/50-edk2-i386-secure.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",
  /usr/share/qemu/firmware/60-edk2-i386.json:            "filename": 
"share/qemu/edk2-i386-code.fd",
  /usr/share/qemu/firmware/60-edk2-i386.json:            "filename": 
"share/qemu/edk2-i386-vars.fd",

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