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Re: [Qemu-devel] [PATCH] vl: fix possible int overflow for qemu_timedate
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] vl: fix possible int overflow for qemu_timedate_diff() |
Date: |
Tue, 6 Feb 2018 16:52:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 |
On 01/02/2018 12:59, Gonglei wrote:
> From: shenghualong <address@hidden>
>
> When the Windows guest users set the time to year 2099,
> the return value of qemu_timedate_diff() will overflow
> with variable clock mode as below format:
>
> <clock offset='variable' adjustment='-1201568405' basis='utc'>
>
> Let's change the return value of qemu_timedate_diff() from
> int to time_t to fix the possible overflow problem.
>
> Signed-off-by: shenghualong <address@hidden>
> Signed-off-by: Gonglei <address@hidden>
Thanks, this makes sense. However, looking at the users, you should
also change the type of:
- the diff variable in hw/timer/m48t59.c function set_alarm;
- the offset argument of the RTC_CHANGE QAPI event (to int64)
- the sec_offset and alm_sec fields of MenelausState in hw/timer/twl92230.c
- the offset argument of qemu_get_timedate.
Thanks,
Paolo
> ---
> include/qemu-common.h | 2 +-
> vl.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/qemu-common.h b/include/qemu-common.h
> index 05319b9..6fb80aa 100644
> --- a/include/qemu-common.h
> +++ b/include/qemu-common.h
> @@ -33,7 +33,7 @@ int qemu_main(int argc, char **argv, char **envp);
> #endif
>
> void qemu_get_timedate(struct tm *tm, int offset);
> -int qemu_timedate_diff(struct tm *tm);
> +time_t qemu_timedate_diff(struct tm *tm);
>
> #define qemu_isalnum(c) isalnum((unsigned char)(c))
> #define qemu_isalpha(c) isalpha((unsigned char)(c))
> diff --git a/vl.c b/vl.c
> index e517a8d..9d225da 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -146,7 +146,7 @@ int nb_nics;
> NICInfo nd_table[MAX_NICS];
> int autostart;
> static int rtc_utc = 1;
> -static int rtc_date_offset = -1; /* -1 means no change */
> +static time_t rtc_date_offset = -1; /* -1 means no change */
> QEMUClockType rtc_clock;
> int vga_interface_type = VGA_NONE;
> static int full_screen = 0;
> @@ -812,7 +812,7 @@ void qemu_get_timedate(struct tm *tm, int offset)
> }
> }
>
> -int qemu_timedate_diff(struct tm *tm)
> +time_t qemu_timedate_diff(struct tm *tm)
> {
> time_t seconds;
>
>