Re: [libvirt] [PATCH 2/5] openvzGetProcessInfo: address clang-detected low-probability flaw

From: Jim Meyering <meyering(a)redhat.com&gt; * 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; + }