Re: [Qemu-devel] [PATCH 1/2] pc_sysfw: Check for qemu_find_file() failure

[Markus Armbruster]

Luiz Capitulino <address@hidden> writes:

> On Thu, 16 Aug 2012 13:41:12 +0200
> Markus Armbruster <address@hidden> wrote:
>
>> pc_fw_add_pflash_drv() ignores qemu_find_file() failure, and happily
>> creates a drive without a medium.
>> 
>> When pc_system_flash_init() asks for its size, bdrv_getlength() fails
>> with -ENOMEDIUM, which isn't checked either.  It fails relatively
>> cleanly only because -ENOMEDIUM isn't a multiple of 4096:
>> 
>>     $ qemu-system-x86_64 -S -vnc :0 -bios nonexistant
>>     qemu: PC system firmware (pflash) must be a multiple of 0x1000
>>     [Exit 1 ]
>> 
>> Fix by handling the qemu_find_file() failure.
>> 
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>>  hw/pc_sysfw.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>> 
>> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
>> index b45f0ac..fd22154 100644
>> --- a/hw/pc_sysfw.c
>> +++ b/hw/pc_sysfw.c
>> @@ -84,6 +84,11 @@ static void pc_fw_add_pflash_drv(void)
>>          bios_name = BIOS_FILENAME;
>>      }
>>      filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
>> +    if (!filename) {
>> +        error_report("Can't open BIOS image %s: %s",
>> +                     bios_name, strerror(errno));
>
> Why not use plain fprintf()? This is called from machine init time, I
> don't think this is ever called in monitor context.

error_report() makes the fact that's an error message obvious and
greppable.  It also prepends the message with PROGNAME:, which is better
than literal "qemu:" when the executable isn't called qemu.  It would
even point to -bios nicely if we bothered to preserve that information
(we lose it by storing the option argument as naked char * without the
location).

> Also, maybe you could add the following patch to this series?
>
>  http://lists.gnu.org/archive/html/qemu-devel/2012-06/msg04686.html

Can do in case I need to respin anyway.

> Although I'm not sure it qualifies for hard-freeze...

I didn't tag my series "for-1.2".  I understand that fixes to
not-so-important stuff aren't welcome at this time even when they're
really simple.

>> +        exit(1);
>> +    }
>>  
>>      opts = drive_add(IF_PFLASH, -1, filename, "readonly=on");
>>