Github user danobi commented on a diff in the pull request:
https://github.com/apache/trafficserver/pull/568#discussion_r59888075
--- Diff: lib/ts/Diags.cc ---
@@ -816,29 +820,39 @@ Diags::set_stdout_output(const char *_bind_stdout)
if (strcmp(_bind_stdout, "") == 0)
return false;
- if (stdout_log) {
- delete stdout_log;
- stdout_log = NULL;
- }
-
- // create backing BaseLogFile for stdout
- stdout_log = new BaseLogFile(_bind_stdout);
+ BaseLogFile *old_stdout_log = stdout_log;
+ BaseLogFile *new_stdout_log = new BaseLogFile(_bind_stdout);
// on any errors we quit
- if (!stdout_log || stdout_log->open_file() !=
BaseLogFile::LOG_FILE_NO_ERROR) {
+ if (!new_stdout_log || new_stdout_log->open_file() !=
BaseLogFile::LOG_FILE_NO_ERROR) {
fprintf(stderr, "[Warning]: unable to open file=%s to bind stdout
to\n", _bind_stdout);
- delete stdout_log;
+ fprintf(stderr, "[Warning]: stdout is currently not bound to
anything\n");
+ delete new_stdout_log;
+ lock();
stdout_log = NULL;
+ unlock();
return false;
}
- if (!stdout_log->m_fp) {
+ if (!new_stdout_log->m_fp) {
fprintf(stderr, "[Warning]: file pointer for stdout %s = NULL\n",
_bind_stdout);
- delete stdout_log;
+ fprintf(stderr, "[Warning]: stdout is currently not bound to
anything\n");
+ delete new_stdout_log;
+ lock();
stdout_log = NULL;
+ unlock();
return false;
}
- return rebind_stdout(fileno(stdout_log->m_fp));
+ // now exchange the stdout_log pointer
+ lock();
+ stdout_log = new_stdout_log;
+ bool ret = rebind_stdout(fileno(new_stdout_log->m_fp));
--- End diff --
It should be fine.
At that point in code, `m_fp` is guaranteed to be pointing to some open
file. If `rebind_stdout()` fails, it's because (1) `fileno()` failed or (2)
`dup2()` failed. If either of those happen, then there's really nothing we can
do about it (AFAICT). So ATS will just plod along without `stdout` or `stderr`
being bound to anything. Fortunately nobody should be writing directly to
either of those streams so we should be in reasonable shape even if
`rebind_...()` fails. Hopefully the next time the log files roll the error will
correct itself.
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