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Re: [Qemu-devel] [PATCH v4 2/4] hw/core: rebase sysbus_get_fw_dev_path()
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v4 2/4] hw/core: rebase sysbus_get_fw_dev_path() to g_strdup_printf() |
Date: |
Mon, 15 Jun 2015 16:23:41 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Laszlo Ersek <address@hidden> writes:
> Cc: Markus Armbruster <address@hidden>
> Cc: Marcel Apfelbaum <address@hidden>
> Cc: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Laszlo Ersek <address@hidden>
> ---
>
> Notes:
> v4:
> - unchanged
>
> v3:
> - new in v3
>
> hw/core/sysbus.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
> index b53c351..0ebb4e2 100644
> --- a/hw/core/sysbus.c
> +++ b/hw/core/sysbus.c
> @@ -281,19 +281,15 @@ static void sysbus_dev_print(Monitor *mon, DeviceState
> *dev, int indent)
> static char *sysbus_get_fw_dev_path(DeviceState *dev)
> {
> SysBusDevice *s = SYS_BUS_DEVICE(dev);
> - char path[40];
> - int off;
> -
> - off = snprintf(path, sizeof(path), "%s", qdev_fw_name(dev));
>
> if (s->num_mmio) {
> - snprintf(path + off, sizeof(path) - off, "@"TARGET_FMT_plx,
> - s->mmio[0].addr);
> - } else if (s->num_pio) {
> - snprintf(path + off, sizeof(path) - off, "@i%04x", s->pio[0]);
> + return g_strdup_printf("%s@"TARGET_FMT_plx, qdev_fw_name(dev),
I'd put a space between "%s@" and TARGET_FMT_plx.
> + s->mmio[0].addr);
> }
> -
> - return g_strdup(path);
> + if (s->num_pio) {
> + return g_strdup_printf("address@hidden", qdev_fw_name(dev),
> s->pio[0]);
> + }
> + return g_strdup(qdev_fw_name(dev));
> }
>
> void sysbus_add_io(SysBusDevice *dev, hwaddr addr,
Would be nice if we didn't have to triplicate qdev_fw_name(), but I
don't have better ideas.
Bonus: no arbitrary length limit. Before your patch, it's 39
characters, and the code breaks catastrophically when qdev_fw_name() is
longer: the second snprintf() is called with its first argument pointing
beyond path[], and its second argument underflowing to a huge size.
Textbook example of how not to use snprintf(). Worth mentioning in the
commit message?
Reviewed-by: Markus Armbruster <address@hidden>