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openvzGetProcessInfo: address clang-detected low-probability flaw

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* src/openvz/openvz_driver.c (openvzGetProcessInfo): Reorganize
so that unexpected /proc/vz/vestat content cannot make us use
uninitialized variables.  Without this change, an input line with
a matching "readvps", but fewer than 4 numbers would result in our
using at least "systime" uninitialized.
This commit is contained in:
Jim Meyering 2010-04-14 09:09:57 +02:00
parent cd7ee20a68
commit 353dd14762
1 changed files with 15 additions and 15 deletions
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30
src/openvz/openvz_driver.c
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@ -1384,14 +1384,15 @@ static int openvzGetProcessInfo(unsigned long long *cpuTime, int vpsid) {
int fd;
char line[1024] ;
unsigned long long usertime, systime, nicetime;
int readvps = 0, ret;
int readvps = vpsid + 1; /* ensure readvps is initially different */
int ret;
/* read statistic from /proc/vz/vestat.
sample:
Version: 2.2
VEID user nice system uptime idle other..
33 78 0 1330 59454597 142650441835148 other..
55 178 0 5340 59424597 542650441835148 other..
VEID user nice system uptime idle other..
33 78 0 1330 59454597 142650441835148 other..
55 178 0 5340 59424597 542650441835148 other..
*/
if ((fd = open("/proc/vz/vestat", O_RDONLY)) == -1)
@ -1400,15 +1401,18 @@ Version: 2.2
/*search line with VEID=vpsid*/
while(1) {
ret = openvz_readline(fd, line, sizeof(line));
if(ret <= 0)
if (ret <= 0)
break;
if (sscanf(line, "%d %llu %llu %llu",
&readvps, &usertime, &nicetime, &systime) != 4)
continue;
if (readvps == vpsid)
break; /*found vpsid*/
if (sscanf (line, "%d %llu %llu %llu",
&readvps, &usertime, &nicetime, &systime) == 4
&& readvps == vpsid) { /*found vpsid*/
/* convert jiffies to nanoseconds */
*cpuTime = (1000ull * 1000ull * 1000ull
* (usertime + nicetime + systime)
/ (unsigned long long)sysconf(_SC_CLK_TCK));
break;
}
}
close(fd);
@ -1418,10 +1422,6 @@ Version: 2.2
if (readvps != vpsid) /*not found*/
return -1;
/* convert jiffies to nanoseconds */
*cpuTime = 1000ull * 1000ull * 1000ull * (usertime + nicetime + systime)
/ (unsigned long long)sysconf(_SC_CLK_TCK);
return 0;
}