log: convert to strnprintf()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/log.c b/src/lxc/log.c
index 7f1d5a86121c34978b29960ddf92787c6b671cbf..fd35a48bb899de637d08b4f48f79dd520ae6b1cb 100644 (file)
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -280,19 +280,19 @@ static int lxc_unix_epoch_to_utc(char *buf, size_t bufsize, const struct timespe
        seconds = (time->tv_sec - d_in_s - h_in_s - (minutes * 60));
 
        /* Make string from nanoseconds. */
-       ret = snprintf(nanosec, sizeof(nanosec), "%"PRId64, (int64_t)time->tv_nsec);
-       if (ret < 0 || (size_t)ret >= sizeof(nanosec))
+       ret = strnprintf(nanosec, sizeof(nanosec), "%"PRId64, (int64_t)time->tv_nsec);
+       if (ret < 0)
                return ret_errno(EIO);
 
        /*
         * Create final timestamp for the log and shorten nanoseconds to 3
         * digit precision.
         */
-       ret = snprintf(buf, bufsize,
+       ret = strnprintf(buf, bufsize,
                       "%" PRId64 "%02" PRId64 "%02" PRId64 "%02" PRId64
                       "%02" PRId64 "%02" PRId64 ".%.3s",
                       year, month, day, hours, minutes, seconds, nanosec);
-       if (ret < 0 || (size_t)ret >= bufsize)
+       if (ret < 0)
                return ret_errno(EIO);
 
        return 0;
@@ -346,6 +346,10 @@ static int log_append_logfile(const struct lxc_log_appender *appender,
        if (ret)
                return ret;
 
+       /*
+        * We allow truncation here which is why we use snprintf() directly
+        * instead of strnprintf().
+        */
        n = snprintf(buffer, sizeof(buffer),
                     "%s%s%s %s %-8s %s - %s:%s:%d - ",
                     log_prefix,
@@ -572,10 +576,10 @@ static char *build_log_path(const char *name, const char *lxcpath)
                return ret_set_errno(NULL, ENOMEM);
 
        if (use_dir)
-               ret = snprintf(p, len, "%s/%s/%s.log", lxcpath, name, name);
+               ret = strnprintf(p, len, "%s/%s/%s.log", lxcpath, name, name);
        else
-               ret = snprintf(p, len, "%s/%s.log", lxcpath, name);
-       if (ret < 0 || (size_t)ret >= len)
+               ret = strnprintf(p, len, "%s/%s.log", lxcpath, name);
+       if (ret < 0)
                return ret_set_errno(NULL, EIO);
 
        return move_ptr(p);