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Re: [Qemu-devel] [PATCH v4 4/6] qdev: add get_pointer_and_free() for tem
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH v4 4/6] qdev: add get_pointer_and_free() for temporary strings |
Date: |
Wed, 26 Feb 2014 10:53:34 +0100 |
On Fri, 21 Feb 2014 15:46:56 +0100
Stefan Hajnoczi <address@hidden> wrote:
> get_pointer() assumes the string has unspecified lifetime (at least as
> long as the object is alive). In some cases we can only produce a
> temporary string that should be freed when get_pointer() is done.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> hw/core/qdev-properties-system.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/hw/core/qdev-properties-system.c
> b/hw/core/qdev-properties-system.c
> index 5f5957e..3bffc01 100644
> --- a/hw/core/qdev-properties-system.c
> +++ b/hw/core/qdev-properties-system.c
> @@ -31,6 +31,20 @@ static void get_pointer(Object *obj, Visitor *v, Property
> *prop,
> visit_type_str(v, &p, name, errp);
> }
>
> +/* Same as get_pointer() but frees heap-allocated print() return value */
> +static void get_pointer_and_free(Object *obj, Visitor *v, Property *prop,
> + char *(*print)(void *ptr),
> + const char *name, Error **errp)
> +{
> + DeviceState *dev = DEVICE(obj);
> + void **ptr = qdev_get_prop_ptr(dev, prop);
> + char *p;
> +
> + p = *ptr ? print(*ptr) : g_strdup("");
> + visit_type_str(v, &p, name, errp);
> + g_free(p);
> +}
it could be better if get_pointer() would free pointer if 3 current users
are converted to return temporary string, something like this:
From 65dbdb27e6ccc555e84ddf898d015827fec04d9c Mon Sep 17 00:00:00 2001
From: Igor Mammedov <address@hidden>
Date: Wed, 26 Feb 2014 10:37:36 +0100
Subject: [PATCH] qdev: make get_pointer() handle temporary strings
get_pointer()'s print() callback might return a heap allocated
string, to avoid adding dedicated get_pointer_foo for this case
convert current print() callbacks to return temporary heap
allocated string and make get_pointer() free it.
Signed-off-by: Igor Mammedov <address@hidden>
---
hw/core/qdev-properties-system.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 5f5957e..d865ea3 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -27,8 +27,9 @@ static void get_pointer(Object *obj, Visitor *v, Property
*prop,
void **ptr = qdev_get_prop_ptr(dev, prop);
char *p;
- p = (char *) (*ptr ? print(*ptr) : "");
+ p = (char *) (*ptr ? print(*ptr) : g_strdup(""));
visit_type_str(v, &p, name, errp);
+ g_free(p);
}
static void set_pointer(Object *obj, Visitor *v, Property *prop,
@@ -93,7 +94,7 @@ static void release_drive(Object *obj, const char *name, void
*opaque)
static const char *print_drive(void *ptr)
{
- return bdrv_get_device_name(ptr);
+ return g_strdup(bdrv_get_device_name(ptr));
}
static void get_drive(Object *obj, Visitor *v, void *opaque,
@@ -148,8 +149,9 @@ static void release_chr(Object *obj, const char *name, void
*opaque)
static const char *print_chr(void *ptr)
{
CharDriverState *chr = ptr;
+ char *val = chr->label ? chr->label : "";
- return chr->label ? chr->label : "";
+ return g_strdup(val);
}
static void get_chr(Object *obj, Visitor *v, void *opaque,
@@ -227,8 +229,9 @@ err:
static const char *print_netdev(void *ptr)
{
NetClientState *netdev = ptr;
+ char *val = netdev->name ? netdev->name : "";
- return netdev->name ? netdev->name : "";
+ return g_strdup(val);
}
static void get_netdev(Object *obj, Visitor *v, void *opaque,
--
1.7.1
> static void set_pointer(Object *obj, Visitor *v, Property *prop,
> int (*parse)(DeviceState *dev, const char *str,
> void **ptr),
- [Qemu-devel] [PATCH v4 0/6] dataplane: switch to N:M devices-per-thread model, Stefan Hajnoczi, 2014/02/21
- [Qemu-devel] [PATCH v4 1/6] rfifolock: add recursive FIFO lock, Stefan Hajnoczi, 2014/02/21
- [Qemu-devel] [PATCH v4 2/6] aio: add aio_context_acquire() and aio_context_release(), Stefan Hajnoczi, 2014/02/21
- [Qemu-devel] [PATCH v4 3/6] iothread: add I/O thread object, Stefan Hajnoczi, 2014/02/21
- [Qemu-devel] [PATCH v4 4/6] qdev: add get_pointer_and_free() for temporary strings, Stefan Hajnoczi, 2014/02/21
- Re: [Qemu-devel] [PATCH v4 4/6] qdev: add get_pointer_and_free() for temporary strings,
Igor Mammedov <=
- [Qemu-devel] [PATCH v4 5/6] iothread: add "iothread" qdev property type, Stefan Hajnoczi, 2014/02/21
- [Qemu-devel] [PATCH v4 6/6] dataplane: replace internal thread with IOThread, Stefan Hajnoczi, 2014/02/21