Turbostat: better error handling for get/read_msr

diff --git a/src/turbostat.c b/src/turbostat.c
index d602ffe6cd3cc85dd83d98bfc2eb241e388b3cb9..ff19cc4b0e6699e085a9633db883b9ad34e90946 100644 (file)
--- a/src/turbostat.c
+++ b/src/turbostat.c
@@ -270,6 +270,7 @@ static int __attribute__((warn_unused_result))
 open_msr(int cpu)
 {
        char pathname[32];
+       int fd;
 
        /* FIXME: Do we really need this, why? */
        if (cpu_migrate(cpu)) {
@@ -277,8 +278,11 @@ open_msr(int cpu)
                return -ERR_CPU_MIGRATE;
        }
 
-       ssnprintf(pathname, 32, "/dev/cpu/%d/msr", cpu);
-       return open(pathname, O_RDONLY);
+       ssnprintf(pathname, STATIC_ARRAY_SIZE(pathname), "/dev/cpu/%d/msr", cpu);
+       fd = open(pathname, O_RDONLY);
+       if (fd < 0)
+               return -ERR_CANT_OPEN_MSR;
+       return fd;
 }
 
 static int __attribute__((warn_unused_result))
@@ -303,7 +307,7 @@ get_msr(int cpu, off_t offset, unsigned long long *msr)
 
        fd = open_msr(cpu);
        if (fd < 0)
-               return -1;
+               return fd;
        retval = read_msr(fd, offset, msr);
        close(fd);
        return retval;
@@ -446,7 +450,7 @@ get_counters(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 
        msr_fd = open_msr(cpu);
        if (msr_fd < 0)
-               return -ERR_CANT_OPEN_MSR;
+               return msr_fd;
 
 #define READ_MSR(msr, dst)                     \
 do {                                           \