Re: [Qemu-devel] [PATCH 01/10] crypto: introduce new module for computing hash digests

[Markus Armbruster]

"Daniel P. Berrange" <address@hidden> writes:

> On Thu, May 28, 2015 at 09:28:20PM +0800, Gonglei wrote:
>> On 2015/5/21 18:56, Daniel P. Berrange wrote:
>> > Introduce a new crypto/ directory that will (eventually) contain
>> > all the cryptographic related code. This initially defines a
>> > wrapper for initializing gnutls and for computing hashes with
>> > gnutls. The former ensures that gnutls is guaranteed to be
>> > initialized exactly once in QEMU regardless of CLI args. The
>> > block quorum code currently fails to initialize gnutls so it
>> > only works by luck, if VNC server TLS is not requested. The
>> > hash APIs avoids the need to litter the rest of the code with
>> > preprocessor checks and simplifies callers by allocating the
>> > correct amount of memory for the requested hash.
>> > 
>> > Signed-off-by: Daniel P. Berrange <address@hidden>
[...]
>> > diff --git a/vl.c b/vl.c
>> > index 15bccc4..72313a4 100644
>> > --- a/vl.c
>> > +++ b/vl.c
>> > @@ -119,6 +119,7 @@ int main(int argc, char **argv)
>> >  #include "qapi/opts-visitor.h"
>> >  #include "qom/object_interfaces.h"
>> >  #include "qapi-event.h"
>> > +#include "crypto/init.h"
>> >  
>> >  #define DEFAULT_RAM_SIZE 128
>> >  
>> > @@ -2777,6 +2778,7 @@ int main(int argc, char **argv, char **envp)
>> >      uint64_t ram_slots = 0;
>> >      FILE *vmstate_dump_file = NULL;
>> >      Error *main_loop_err = NULL;
>> > +    Error *err = NULL;
>> >  
>> >      qemu_init_cpu_loop();
>> >      qemu_mutex_lock_iothread();
>> > @@ -2819,6 +2821,12 @@ int main(int argc, char **argv, char **envp)
>> >  
>> >      runstate_init();
>> >  
>> > +    if (qcrypto_init(&err) < 0) {
>> > +        fprintf(stderr, "Cannot initialize crypto: %s\n",
>> > +                error_get_pretty(err));
>> > +        error_free(err);
>> 
>> This free is superflous (before exit) IMO.
>
> Personally I always free variables like this so valgrind doesn't complain
> about leaks.

Marginally useful when you do it for the complete program.  QEMU
doesn't, and making all of QEMU do it would be a fool's errand.