Re: [Qemu-devel] [PATCH V13 4/6] create some QemuOpts functons

[Dong Xu Wang]

On 2013/5/6 20:20, Markus Armbruster wrote:
> Dong Xu Wang <address@hidden> writes:
>
> > These functions will be used in next commit. qemu_opt_get_(*)_del functions
> > are used to make sure we have the same behaviors as before: after get an
> > option value, options++.
>
> I don't understand the last sentence.
>
> > Signed-off-by: Dong Xu Wang <address@hidden>
> > ---
> >   include/qemu/option.h |  11 +++++-
> >   util/qemu-option.c    | 103 ++++++++++++++++++++++++++++++++++++++++++++++----
> >   2 files changed, 105 insertions(+), 9 deletions(-)
> >
> > diff --git a/include/qemu/option.h b/include/qemu/option.h
> > index c7a5c14..d63e447 100644
> > --- a/include/qemu/option.h
> > +++ b/include/qemu/option.h
> > @@ -108,6 +108,7 @@ struct QemuOptsList {
> >   };
> >
> >   const char *qemu_opt_get(QemuOpts *opts, const char *name);
> > +const char *qemu_opt_get_del(QemuOpts *opts, const char *name);
> >   /**
> >    * qemu_opt_has_help_opt:
> >    * @opts: options to search for a help request
> > @@ -121,13 +122,18 @@ const char *qemu_opt_get(QemuOpts *opts, const char 
> > *name);
> >    */
> >   bool qemu_opt_has_help_opt(QemuOpts *opts);
> >   bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval);
> > +bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval);
> >   uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t 
> > defval);
> >   uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval);
> > +uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
> > +                               uint64_t defval);
> >   int qemu_opt_set(QemuOpts *opts, const char *name, const char *value);
> > +int qemu_opt_replace_set(QemuOpts *opts, const char *name, const char *value);
> >   void qemu_opt_set_err(QemuOpts *opts, const char *name, const char *value,
> >                         Error **errp);
> >   int qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val);
> >   int qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val);
> > +int qemu_opt_replace_set_number(QemuOpts *opts, const char *name, int64_t val);
> >   typedef int (*qemu_opt_loopfunc)(const char *name, const char *value, void 
> > *opaque);
> >   int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
> >                        int abort_on_failure);
> > @@ -144,7 +150,10 @@ const char *qemu_opts_id(QemuOpts *opts);
> >   void qemu_opts_del(QemuOpts *opts);
> >   void qemu_opts_validate(QemuOpts *opts, const QemuOptDesc *desc, Error 
> > **errp);
> >   int qemu_opts_do_parse(QemuOpts *opts, const char *params, const char 
> > *firstname);
> > -QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params, int 
> > permit_abbrev);
> > +int qemu_opts_do_parse_replace(QemuOpts *opts, const char *params,
> > +                               const char *firstname);
> > +QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params,
> > +                          int permit_abbrev);
> >   void qemu_opts_set_defaults(QemuOptsList *list, const char *params,
> >                               int permit_abbrev);
> >   QemuOpts *qemu_opts_from_qdict(QemuOptsList *list, const QDict *qdict,
> > diff --git a/util/qemu-option.c b/util/qemu-option.c
> > index 0488c27..5db6d76 100644
> > --- a/util/qemu-option.c
> > +++ b/util/qemu-option.c
> > @@ -33,6 +33,8 @@
> >   #include "qapi/qmp/qerror.h"
> >   #include "qemu/option_int.h"
> >
> > +static void qemu_opt_del(QemuOpt *opt);
> > +
> >   /*
> >    * Extracts the name of an option from the parameter string (p points at the
> >    * first byte of the option name)
> > @@ -549,6 +551,16 @@ const char *qemu_opt_get(QemuOpts *opts, const char *name)
>     const char *qemu_opt_get(QemuOpts *opts, const char *name)
>     {
>         QemuOpt *opt = qemu_opt_find(opts, name);
>         const QemuOptDesc *desc;
>         desc = find_desc_by_name(opts->list->desc, name);
>
>         return opt ? opt->str :
> >           (desc && desc->def_value_str ? desc->def_value_str : NULL);
> >   }
> >
> > +const char *qemu_opt_get_del(QemuOpts *opts, const char *name)
> > +{
> > +    QemuOpt *opt = qemu_opt_find(opts, name);
> > +    const char *str = opt ? g_strdup(opt->str) : NULL;
> > +    if (opt) {
> > +        qemu_opt_del(opt);
> > +    }
> > +    return str;
> > +}
> > +
>
> Unlike qemu_opt_del(), this one doesn't use def_value_str.  Why?  Isn't
> that a trap for users of this function?
>
> Same question for the qemu_opt_get_FOO_del() that follow.
>
> >   bool qemu_opt_has_help_opt(QemuOpts *opts)
> >   {
> >       QemuOpt *opt;
> > @@ -577,6 +589,22 @@ bool qemu_opt_get_bool(QemuOpts *opts, const char *name, 
> > bool defval)
> >       return opt->value.boolean;
> >   }
> >
> > +bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval)
> > +{
> > +    QemuOpt *opt = qemu_opt_find(opts, name);
> > +    bool ret;
> > +
> > +    if (opt == NULL) {
> > +        return defval;
> > +    }
> > +    ret = opt->value.boolean;
> > +    assert(opt->desc && opt->desc->type == QEMU_OPT_BOOL);
> > +    if (opt) {
> > +        qemu_opt_del(opt);
> > +    }
> > +    return ret;
> > +}
> > +
> >   uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t 
> > defval)
> >   {
> >       QemuOpt *opt = qemu_opt_find(opts, name);
> > @@ -609,6 +637,23 @@ uint64_t qemu_opt_get_size(QemuOpts *opts, const char 
> > *name, uint64_t defval)
> >       return opt->value.uint;
> >   }
> >
> > +uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
> > +                               uint64_t defval)
> > +{
> > +    QemuOpt *opt = qemu_opt_find(opts, name);
> > +    uint64_t ret;
> > +
> > +    if (opt == NULL) {
> > +        return defval;
> > +    }
> > +    ret = opt->value.uint;
> > +    assert(opt->desc && opt->desc->type == QEMU_OPT_SIZE);
> > +    if (opt) {
> > +        qemu_opt_del(opt);
> > +    }
> > +    return ret;
> > +}
> > +
> >   static void qemu_opt_parse(QemuOpt *opt, Error **errp)
> >   {
> >       if (opt->desc == NULL)
> > @@ -646,7 +691,7 @@ static bool opts_accepts_any(const QemuOpts *opts)
> >   }
> >
> >   static void opt_set(QemuOpts *opts, const char *name, const char *value,
> > -                    bool prepend, Error **errp)
> > +                    bool prepend, bool replace, Error **errp)
> >   {
> >       QemuOpt *opt;
> >       const QemuOptDesc *desc;
> > @@ -658,6 +703,11 @@ static void opt_set(QemuOpts *opts, const char *name, 
> > const char *value,
> >           return;
> >       }
> >
> > +    opt = qemu_opt_find(opts, name);
> > +    if (replace && opt) {
> > +        qemu_opt_del(opt);
> > +    }
> > +
> >       opt = g_malloc0(sizeof(*opt));
> >       opt->name = g_strdup(name);
> >       opt->opts = opts;
> > @@ -667,7 +717,6 @@ static void opt_set(QemuOpts *opts, const char *name, const 
> > char *value,
> >           QTAILQ_INSERT_TAIL(&opts->head, opt, next);
> >       }
> >       opt->desc = desc;
> > -    opt->str = g_strdup(value);
> >       opt->str = g_strdup(value ?: desc->def_value_str);
> >       qemu_opt_parse(opt, &local_err);
> >       if (error_is_set(&local_err)) {
>
> Here you plug the leak you created in PATCH 1/6.
>
> > @@ -680,7 +729,29 @@ int qemu_opt_set(QemuOpts *opts, const char *name, const 
> > char *value)
> >   {
> >       Error *local_err = NULL;
> >
> > -    opt_set(opts, name, value, false, &local_err);
> > +    opt_set(opts, name, value, false, false, &local_err);
> > +    if (error_is_set(&local_err)) {
> > +        qerror_report_err(local_err);
> > +        error_free(local_err);
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +/*
> > + * If name exists, the function will delete the opt first and then add a new
> > + * one.
> > + */
> > +int qemu_opt_replace_set(QemuOpts *opts, const char *name, const char *value)
> > +{
> > +    Error *local_err = NULL;
> > +    QemuOpt *opt = qemu_opt_find(opts, name);
> > +
> > +    if (opt) {
> > +        qemu_opt_del(opt);
> > +    }
>
> Why?  Won't opt_set() delete it already?
No, opt_set will not delete it, but add a new opt. In block layer, while 
parsing options, if the parameter is parsed, it should be deleted and 
won't be used again, so I delete it manually.

> Same question for the qemu_opt_replace_set_FOO() that follow.
>
> > +    opt_set(opts, name, value, false, true, &local_err);
> >       if (error_is_set(&local_err)) {
> >           qerror_report_err(local_err);
> >           error_free(local_err);
> > @@ -693,7 +764,7 @@ int qemu_opt_set(QemuOpts *opts, const char *name, const 
> > char *value)
> >   void qemu_opt_set_err(QemuOpts *opts, const char *name, const char *value,
> >                         Error **errp)
> >   {
> > -    opt_set(opts, name, value, false, errp);
> > +    opt_set(opts, name, value, false, false, errp);
> >   }
> >
> >   int qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val)
> > @@ -740,6 +811,16 @@ int qemu_opt_set_number(QemuOpts *opts, const char *name, 
> > int64_t val)
> >       return 0;
> >   }
> >
> > +int qemu_opt_replace_set_number(QemuOpts *opts, const char *name, int64_t val)
> > +{
> > +    QemuOpt *opt = qemu_opt_find(opts, name);
> > +
> > +    if (opt) {
> > +        qemu_opt_del(opt);
> > +    }
> > +    return qemu_opt_set_number(opts, name, val);
> > +}
> > +
> >   int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
> >                        int abort_on_failure)
> >   {
> > @@ -917,7 +998,7 @@ int qemu_opts_print(QemuOpts *opts)
> >   }
> >
> >   static int opts_do_parse(QemuOpts *opts, const char *params,
> > -                         const char *firstname, bool prepend)
> > +                         const char *firstname, bool prepend, bool replace)
> >   {
> >       char option[128], value[1024];
> >       const char *p,*pe,*pc;
> > @@ -953,7 +1034,7 @@ static int opts_do_parse(QemuOpts *opts, const char 
> > *params,
> >           }
> >           if (strcmp(option, "id") != 0) {
> >               /* store and parse */
> > -            opt_set(opts, option, value, prepend, &local_err);
> > +            opt_set(opts, option, value, prepend, replace, &local_err);
> >               if (error_is_set(&local_err)) {
> >                   qerror_report_err(local_err);
> >                   error_free(local_err);
> > @@ -969,7 +1050,13 @@ static int opts_do_parse(QemuOpts *opts, const char 
> > *params,
> >
> >   int qemu_opts_do_parse(QemuOpts *opts, const char *params, const char 
> > *firstname)
> >   {
> > -    return opts_do_parse(opts, params, firstname, false);
> > +    return opts_do_parse(opts, params, firstname, false, false);
> > +}
> > +
> > +int qemu_opts_do_parse_replace(QemuOpts *opts, const char *params,
> > +                               const char *firstname)
> > +{
> > +    return opts_do_parse(opts, params, firstname, false, true);
> >   }
> >
> >   static QemuOpts *opts_parse(QemuOptsList *list, const char *params,
> > @@ -1008,7 +1095,7 @@ static QemuOpts *opts_parse(QemuOptsList *list, const 
> > char *params,
> >           return NULL;
> >       }
> >
> > -    if (opts_do_parse(opts, params, firstname, defaults) != 0) {
> > +    if (opts_do_parse(opts, params, firstname, defaults, false) != 0) {
> >           qemu_opts_del(opts);
> >           return NULL;
> >       }