Re: [PATCH v4 2/6] util: refactor qemu_open_old to split off variadic args handling

[Markus Armbruster]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Tue, Aug 25, 2020 at 04:56:40PM +0200, Markus Armbruster wrote:
>> Daniel P. Berrangé <berrange@redhat.com> writes:
>> 
>> > This simple refactoring prepares for future patches. The variadic args
>> > handling is split from the main bulk of the open logic. The duplicated
>> > calls to open() are removed in favour of updating the "flags" variable
>> > to have O_CLOEXEC.
>> >
>> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
>> > ---
>> >  util/osdep.c | 40 +++++++++++++++++++++++++++-------------
>> >  1 file changed, 27 insertions(+), 13 deletions(-)
>> >
>> > diff --git a/util/osdep.c b/util/osdep.c
>> > index 9df1b6adec..9ff92551e7 100644
>> > --- a/util/osdep.c
>> > +++ b/util/osdep.c
>> > @@ -22,6 +22,7 @@
>> >   * THE SOFTWARE.
>> >   */
>> >  #include "qemu/osdep.h"
>> > +#include "qapi/error.h"
>> >  
>> >  /* Needed early for CONFIG_BSD etc. */
>> >  
>> > @@ -282,10 +283,10 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t 
>> > len, bool exclusive)
>> >  /*
>> >   * Opens a file with FD_CLOEXEC set
>> >   */
>> > -int qemu_open_old(const char *name, int flags, ...)
>> > +static int
>> > +qemu_open_internal(const char *name, int flags, mode_t mode)
>> >  {
>> >      int ret;
>> > -    int mode = 0;
>> >  
>> >  #ifndef _WIN32
>> >      const char *fdset_id_str;
>> > @@ -323,22 +324,35 @@ int qemu_open_old(const char *name, int flags, ...)
>> >      }
>> >  #endif
>> >  
>> > -    if (flags & O_CREAT) {
>> > -        va_list ap;
>> > -
>> > -        va_start(ap, flags);
>> > -        mode = va_arg(ap, int);
>> > -        va_end(ap);
>> > -    }
>> > -
>> >  #ifdef O_CLOEXEC
>> > -    ret = open(name, flags | O_CLOEXEC, mode);
>> > -#else
>> > +    flags |= O_CLOEXEC;
>> > +#endif /* O_CLOEXEC */
>> > +
>> >      ret = open(name, flags, mode);
>> > +
>> > +#ifndef O_CLOEXEC
>> >      if (ret >= 0) {
>> >          qemu_set_cloexec(ret);
>> >      }
>> > -#endif
>> > +#endif /* ! O_CLOEXEC */
>> 
>> I dislike this part, to be honest.  I find
>> 
>>     #ifdef O_CLOEXEC
>>         flags |= O_CLOEXEC;
>>     #endif /* O_CLOEXEC */
>> 
>>         ret = open(name, flags, mode);
>> 
>>     #ifndef O_CLOEXEC
>>         if (ret >= 0) {
>>             qemu_set_cloexec(ret);
>>         }
>>     #endif /* ! O_CLOEXEC */
>> 
>> harder to read than
>> 
>>     #ifdef O_CLOEXEC
>>         ret = open(name, flags | O_CLOEXEC, mode);
>>     #else
>>         ret = open(name, flags, mode);
>>         if (ret >= 0) {
>>             qemu_set_cloexec(ret);
>>         }
>>     #endif
>
> We're re-using 'flags' variable again in a later patch and want to
> have O_CLOEXEC present in it then too.

I guess you mean PATCH 5.  I'll get back the the issue there.