[libvirt] [dbus PATCH 14/25] Implement FSFreeze method for Domain Interface

[Pavel Hrdina]

On Tue, Apr 17, 2018 at 02:04:33PM +0200, Katerina Koukiou wrote:
> Signed-off-by: Katerina Koukiou <kkoukiou at redhat.com>
> ---
>  data/org.libvirt.Domain.xml |  7 +++++++
>  src/domain.c                | 40 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 47 insertions(+)
> 
> diff --git a/data/org.libvirt.Domain.xml b/data/org.libvirt.Domain.xml
> index fb2bcce..66cf5e2 100644
> --- a/data/org.libvirt.Domain.xml
> +++ b/data/org.libvirt.Domain.xml
> @@ -135,6 +135,13 @@
>        <arg name="xml" type="s" direction="in"/>
>        <arg name="flags" type="u" direction="in"/>
>      </method>
> +    <method name="FSFreeze">
> +      <annotation name="org.gtk.GDBus.DocString"
> +        value="See https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainFSFreeze"/>
> +      <arg name="mountpoints" type="as" direction="in"/>
> +      <arg name="flags" type="u" direction="in"/>
> +      <arg name="frozenFilesystems" type="u" direction="out"/>
> +    </method>
>      <method name="GetBlkioParameters">
>        <annotation name="org.gtk.GDBus.DocString"
>          value="See https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetBlkioParameters"/>
> diff --git a/src/domain.c b/src/domain.c
> index 2fd8343..04115d1 100644
> --- a/src/domain.c
> +++ b/src/domain.c
> @@ -693,6 +693,45 @@ virtDBusDomainDetachDevice(GVariant *inArgs,
>          virtDBusUtilSetLastVirtError(error);
>  }
>  
> +static void
> +virtDBusDomainFSFreeze(GVariant *inArgs,
> +                       GUnixFDList *inFDs G_GNUC_UNUSED,
> +                       const gchar *objectPath,
> +                       gpointer userData,
> +                       GVariant **outArgs,
> +                       GUnixFDList **outFDs G_GNUC_UNUSED,
> +                       GError **error)
> +{
> +    virtDBusConnect *connect = userData;
> +    g_autoptr(virDomain) domain = NULL;
> +    g_autofree const gchar **mountpoints = NULL;
> +    GVariantIter *iter;
> +    gsize nmountpoints = 0;
> +    guint flags;
> +    gint ret;
> +
> +    g_variant_get(inArgs, "(asu)", &iter, &flags);
> +
> +    nmountpoints = g_variant_iter_n_children(iter);
> +    if (nmountpoints) {
> +        mountpoints = g_new0(const gchar*, nmountpoints + 1);
> +        while (g_variant_iter_loop(iter, "s", &mountpoints[nmountpoints-1]))
> +            nmountpoints++;
> +        nmountpoints--;
> +        g_variant_iter_free(iter);
> +    }

This code will not work for nmountpoints >= 2.

At the first line you get a number of mountpoints, let's say it's
2 ("/root", "/home").

Then you allocate nmountpoints + 1 array of strings, the array should
have only nmountpoints elements.

The while loop is the place where it actually fails:

1 cycle: g_variant_iter_loop(iter, "s", &mountpoints[3-1])

    - this will not fail because mountpoints[2] is still allocated

2 cycle: g_variant_iter_loop(iter, "s", &mountpoints[4-1])

    - there the program crashes because mountpoints[3] is not allocated

Another issue here is that using "s" as signature makes a copy of the
string and it needs to be freed, in this case "&s" would be better.


One possible way how the code can look like:

    
    const gchar **tmp;

    nmountpoints = g_variant_iter_n_children(iter);
    if (nmountpoints > 0) {
        mountpoints = g_new0(const gchar*, nmountpoints);
        tmp = mountpoints;
        while (g_variant_iter_loop(iter, "&s", tmp))
            tmp++;
        g_variant_iter_free(iter);
    }

> +
> +    domain = virtDBusDomainGetVirDomain(connect, objectPath, error);
> +    if (!domain)
> +        return;
> +
> +    ret = virDomainFSFreeze(domain, (const gchar **)mountpoints, nmountpoints, flags);

There is no need to typecast mountpoints and the line is too long.

> +    if (ret < 0)
> +        virtDBusUtilSetLastVirtError(error);

Missing return.

Pavel
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