Looking at all merge-lists QemuOptsList, here is how they access their
QemuOpts:
reopen_opts in qemu-io-cmds.c ("qemu-img reopen -o")
qemu_opts_find(&reopen_opts, NULL)
empty_opts in qemu-io.c ("qemu-io open -o")
qemu_opts_find(&empty_opts, NULL)
qemu_rtc_opts ("-rtc")
qemu_find_opts_singleton("rtc")
qemu_machine_opts ("-M")
qemu_find_opts_singleton("machine")
qemu_action_opts ("-name")
qemu_opts_foreach->process_runstate_actions
qemu_boot_opts ("-boot")
in hw/nvram/fw_cfg.c and hw/s390x/ipl.c:
QTAILQ_FIRST(&qemu_find_opts("bootopts")->head)
in softmmu/vl.c:
qemu_opts_find(qemu_find_opts("boot-opts"), NULL)
qemu_name_opts ("-name")
qemu_opts_foreach->parse_name
parse_name does not use id
qemu_mem_opts ("-m")
qemu_find_opts_singleton("memory")
qemu_icount_opts ("-icount")
qemu_opts_foreach->do_configure_icount
do_configure_icount->icount_configure
icount_configure does not use id
qemu_smp_opts ("-smp")
qemu_opts_find(qemu_find_opts("smp-opts"), NULL)
qemu_spice_opts ("-spice")
QTAILQ_FIRST(&qemu_spice_opts.head)
i.e. they don't need an id. Sometimes its presence is ignored
(e.g. when using qemu_opts_foreach), sometimes all the options
with the id are skipped, sometimes only the first option on the
command line is considered. -boot does two different things
depending on who's looking at the options.
With this patch we just forbid id on merge-lists QemuOptsLists; if the
command line still works, it has the same semantics as before.
qemu_opts_create's fail_if_exists parameter is now unnecessary:
- it is unused if id is NULL
- opts_parse only passes false if reached from qemu_opts_set_defaults,
in which case this patch enforces that id must be NULL
- other callers that can pass a non-NULL id always set it to true
Assert that it is true in the only case where "fail_if_exists" matters,
i.e. "id && !lists->merge_lists". This means that if an id is present,
duplicates are always forbidden, which was already the status quo.
Discounting the case that aborts as it's not user-controlled (it's
"just" a matter of inspecting qemu_opts_create callers), the paths
through qemu_opts_create can be summarized as:
- merge_lists = true: singleton opts with NULL id; non-NULL id fails
- merge_lists = false: always return new opts; non-NULL id fails if dup
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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