Daniel P. Berrangé <[email protected]> writes:
> On Thu, Feb 19, 2026 at 11:08:45AM +0100, Markus Armbruster wrote:
>> Daniel P. Berrangé <[email protected]> writes:
>>
>> > The error_report function can include the program name in any
>> > messages it prints. The qemu_log function has no equivalent
>> > behaviour.
>> >
>> > This introduces support for a "program name" in the new
>> > messages API, which will be included by default for all
>> > binaries.
>> >
>> > This change tweaks the output of the error_report function,
>> > adding a space between the program name and the location
>> > info.
>>
>> Why?
>
> Looking again, arguably that is fixing a pre-existing bug
>
> The current code is:
>
> if (!monitor_cur() && g_get_prgname()) {
> error_printf("%s:", g_get_prgname());
> sep = " ";
> }
> switch (cur_loc->kind) {
> case LOC_CMDLINE:
> argp = cur_loc->ptr;
> for (i = 0; i < cur_loc->num; i++) {
> error_printf("%s%s", sep, argp[i]);
> sep = " ";
> }
> error_printf(": ");
> break;
> case LOC_FILE:
> error_printf("%s:", (const char *)cur_loc->ptr);
> if (cur_loc->num) {
> error_printf("%d:", cur_loc->num);
> }
> error_printf(" ");
> break;
> default:
> error_printf("%s", sep);
> }
>
>
> Notice how we honour "sep" for LOC_CMDLINE but ignore
> it for LOC_FILE.
This works exactly as intended. To illustrate, add
error_report("test, ignore");
to qdev_device_add(), then:
$ cat t.cfg
[device]
driver = "usb-kbd"
$ qemu-system-x86_64 -S -display none -machine usb=on -device usb-kbd
-readconfig t.cfg -monitor stdio
QEMU 10.2.50 monitor - type 'help' for more information
qemu-system-x86_64: -device usb-kbd: test, ignore
qemu-system-x86_64:t.cfg:2: test, ignore
(qemu) device_add usb-kbd
test, ignore
The format
program:sourcefile:lineno: message
conforms to the GNU Coding Standards at
<https://www.gnu.org/prep/standards/standards.html#Errors>, and matches
common practice.
> With the program name printing moved out into a separate
> function, the space is always printed. No change for
> LOC_CMDLINE, but new whitespace for LOC_FILE.
>
> Should have changed this in a separate patch.
>
>> > The qemu_log function will gain the program name. This
>> > can be easily seen with the 'log' trace backend, and how it
>> > is now more closely matching error_report output.
>> >
>> > Before:
>> >
>> > # qemu-system-x86_64 -object tls-creds-x509,id=t0,dir=fish -d
>> > 'trace:qcrypto*'
>> > qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x5584e13937f0
>> > dir=fish
>> > qcrypto_tls_creds_get_path TLS creds path creds=0x5584e13937f0
>> > filename=ca-cert.pem path=<none>
>> > qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No
>> > such file or directory
>> >
>> > After:
>> >
>> > # qemu-system-x86_64 -object tls-creds-x509,id=t0,dir=fish -d
>> > 'trace:qcrypto*'
>> > qemu-system-x86_64: qcrypto_tls_creds_x509_load TLS creds x509 load
>> > creds=0x5584e13937f0 dir=fish
>> > qemu-system-x86_64: qcrypto_tls_creds_get_path TLS creds path
>> > creds=0x5584e13937f0 filename=ca-cert.pem path=<none>
>> > qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No
>> > such file or directory
>> >
>> > When adding this the '-msg program-name=on|off' option is
>> > introduced, so that the program name (which is enabled by
>> > default) can be supressed if desired. This could be useful
>> > if '-msg guest-name=on' is being used as a more informative
>> > identifier.
>>
>> Separate patch?
>
> It is a bit of a borderline decision, but I felt the knob to turn it
> off should be in the same patch that force enables it.
Peter objected to making the logs more verbose by default, and I think
he has a point. Perhaps having errors and logs share a general format
is useful anyway, and perhaps making it even more configurable is as
well. I figure we'd need separate configuration for logs and for error
messages.
Let's get to rough consensus before we debate the finer points like this
one.
>> > Reviewed-by: Richard Henderson <[email protected]>
>> > Signed-off-by: Daniel P. Berrangé <[email protected]>
>
> With regards,
> Daniel
