Re: [Qemu-devel] [PATCH 01/12] monitor: use monitor_handle_fd_param for non-Error-friendly users of named fds

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/09/2012 22:42, Luiz Capitulino ha scritto:
> On Wed, 19 Sep 2012 16:31:04 +0200
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> monitor_handle_fd_param and monitor_get_fd are mostly the same, except
>> that monitor_handle_fd_param does error reporting wrong.  Use it in all
>> other places that do it wrong, instead of reinventing it.
> 
> Hmm, why do we want to do this?
> 
> As far as I understand it the main difference between the two functions
> is that if fdname is a number (for a weak definition of number),
> monitor_handle_fd_param() assumes that the fd already exists in qemu
> (eg. it was passed by the parent process). 

Oops, right, I remembered it was the other way round (i.e. first search
for a named file descriptor, and fall back to a numeric one).

> Another side effect is that you add the possibility of functions
> changing from monitor_get_fd() to monitor_handle_fd_param() to also take
> fds passed by the parent process. Might be positive, but I wonder if that's
> useful for the commands you're changing.

Making behavior more uniform may be a useful thing on its own.  We might
even consider moving it to monitor_get_fd (with the above tweak for
compatibility).  BTW, pci-assign.c is open-coding
monitor_handle_fd_param (including the numeric file descriptor behavior)
and we can remove the surrounding if.

Paolo

>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  hw/kvm/pci-assign.c | 4 +---
>>  migration-fd.c      | 3 +--
>>  monitor.c           | 6 +++---
>>  3 file modificati, 5 inserzioni(+), 8 rimozioni(-)
>>
>> diff --git a/hw/kvm/pci-assign.c b/hw/kvm/pci-assign.c
>> index 05b93d9..8b96a57 100644
>> --- a/hw/kvm/pci-assign.c
>> +++ b/hw/kvm/pci-assign.c
>> @@ -582,10 +582,8 @@ static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg,
>>          if (qemu_isdigit(pci_dev->configfd_name[0])) {
>>              dev->config_fd = strtol(pci_dev->configfd_name, NULL, 0);
>>          } else {
>> -            dev->config_fd = monitor_get_fd(cur_mon, pci_dev->configfd_name);
>> +            dev->config_fd = monitor_handle_fd_param(cur_mon, pci_dev->configfd_name);
>>              if (dev->config_fd < 0) {
>> -                error_report("%s: (%s) unkown", __func__,
>> -                             pci_dev->configfd_name);
>>                  return 1;
>>              }
>>          }
>> diff --git a/migration-fd.c b/migration-fd.c
>> index 50138ed..3eb53d9 100644
>> --- a/migration-fd.c
>> +++ b/migration-fd.c
>> @@ -75,9 +75,8 @@ static int fd_close(MigrationState *s)
>>  
>>  int fd_start_outgoing_migration(MigrationState *s, const char *fdname)
>>  {
>> -    s->fd = monitor_get_fd(cur_mon, fdname);
>> +    s->fd = monitor_handle_fd_param(cur_mon, fdname);
>>      if (s->fd == -1) {
>> -        DPRINTF("fd_migration: invalid file descriptor identifier\n");
>>          goto err_after_get_fd;
>>      }
>>  
>> diff --git a/monitor.c b/monitor.c
>> index 67064e2..4901600 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -951,7 +951,7 @@ static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_d
>>      CharDriverState *s;
>>  
>>      if (strcmp(protocol, "spice") == 0) {
>> -        int fd = monitor_get_fd(mon, fdname);
>> +        int fd = monitor_handle_fd_param(mon, fdname);
>>          int skipauth = qdict_get_try_bool(qdict, "skipauth", 0);
>>          int tls = qdict_get_try_bool(qdict, "tls", 0);
>>          if (!using_spice) {
>> @@ -965,13 +965,13 @@ static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_d
>>          return 0;
>>  #ifdef CONFIG_VNC
>>      } else if (strcmp(protocol, "vnc") == 0) {
>> -	int fd = monitor_get_fd(mon, fdname);
>> +	int fd = monitor_handle_fd_param(mon, fdname);
>>          int skipauth = qdict_get_try_bool(qdict, "skipauth", 0);
>>  	vnc_display_add_client(NULL, fd, skipauth);
>>  	return 0;
>>  #endif
>>      } else if ((s = qemu_chr_find(protocol)) != NULL) {
>> -	int fd = monitor_get_fd(mon, fdname);
>> +	int fd = monitor_handle_fd_param(mon, fdname);
>>  	if (qemu_chr_add_client(s, fd) < 0) {
>>  	    qerror_report(QERR_ADD_CLIENT_FAILED);
>>  	    return -1;
>