Eric Blake wrote:
On 04/14/2010 02:46 AM, Jim Meyering wrote:
From: Jim Meyering <meyering@redhat.com>
* 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. --- src/openvz/openvz_driver.c | 30 +++++++++++++++--------------- 1 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/src/openvz/openvz_driver.c b/src/openvz/openvz_driver.c index 95c4236..47004d6 100644 --- a/src/openvz/openvz_driver.c +++ b/src/openvz/openvz_driver.c @@ -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;
- 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; + }
ACK that the rewrite fixes the problem. However, there's still the
Thanks for the review.
issue that we're using sscanf in the first place, instead of virStrToLong_ull; do you want to prepare a followup patch, or shall I?
I am in no big hurry on that front, at least not for this particular case, where the risk of bogus input is probably negligible.