[Qemu-devel] [PATCH] vl: fix possible int overflow for qemu_timedate_diff()

[Gonglei]

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>
---
 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;
 
-- 
1.8.3.1