Re: [PATCH] maintenance: compare output of pthread functions for inequality with 0
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Dec 2, 2022, 18:10 UTC
- Message-ID
- <221202.86k039fz7x.gmgdl@evledraar.gmail.com>
- In-Reply-To
- <pull.1389.git.git.1670000578395.gitgitgadget@gmail.com>
On Fri, Dec 02 2022, Rose via GitGitGadget wrote:
Show 72 quoted lines
> From: Seija <doremylover123@gmail.com>
>
> The documentation for pthread_create and pthread_sigmask state that:
>
> "On success, pthread_create() returns 0;
> on error, it returns an error number"
>
> As such, we ought to check for an error
> by seeing if the output is not 0.
>
> Checking for "less than" is a mistake
> as the error code numbers can be greater than 0.
>
> Signed-off-by: Seija <doremylover123@gmail.com>
> ---
> maintenance: compare output of pthread functions for inequality with 0
>
> The documentation for pthread_create and pthread_sigmask state that "On
> success, pthread_create() returns 0; on error, it returns an error
> number, and the contents of *thread are undefined."
>
> As such, we ought to check for an error by seeing if the output is not
> 0, rather than being less than 0, since nothing stops these functions
> from returning a positive number.
>
> Signed-off by: Seija doremylover123@gmail.com
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1389%2FAtariDreams%2Faddress-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1389/AtariDreams/address-v1
> Pull-Request: https://github.com/git/git/pull/1389
>
> builtin/fsmonitor--daemon.c | 4 ++--
> run-command.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c
> index 6f30a4f93a7..52a08bb3b57 100644
> --- a/builtin/fsmonitor--daemon.c
> +++ b/builtin/fsmonitor--daemon.c
> @@ -1209,7 +1209,7 @@ static int fsmonitor_run_daemon_1(struct fsmonitor_daemon_state *state)
> * events.
> */
> if (pthread_create(&state->listener_thread, NULL,
> - fsm_listen__thread_proc, state) < 0) {
> + fsm_listen__thread_proc, state)) {
> ipc_server_stop_async(state->ipc_server_data);
> err = error(_("could not start fsmonitor listener thread"));
> goto cleanup;
> @@ -1220,7 +1220,7 @@ static int fsmonitor_run_daemon_1(struct fsmonitor_daemon_state *state)
> * Start the health thread to watch over our process.
> */
> if (pthread_create(&state->health_thread, NULL,
> - fsm_health__thread_proc, state) < 0) {
> + fsm_health__thread_proc, state)) {
> ipc_server_stop_async(state->ipc_server_data);
> err = error(_("could not start fsmonitor health thread"));
> goto cleanup;
> diff --git a/run-command.c b/run-command.c
> index 48b9ba6d6f0..756f1839aab 100644
> --- a/run-command.c
> +++ b/run-command.c
> @@ -1019,7 +1019,7 @@ static void *run_thread(void *data)
> sigset_t mask;
> sigemptyset(&mask);
> sigaddset(&mask, SIGPIPE);
> - if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
> + if (pthread_sigmask(SIG_BLOCK, &mask, NULL)) {
> ret = error("unable to block SIGPIPE in async thread");
> return (void *)ret;
> }
>
> base-commit: 805265fcf7a737664a8321aaf4a0587b78435184This looks good to me, and skimming through the rest of the pthread_create() it seems the rest of the code in-tree is correct.
But (and especially if you're interested) we really should follow-up here and fix the "error()" etc. part of this. After this we have cases in-tree where we on failure:
* Call die_errno() (good) * Call die(), error() etc., but with a manual strerror() argument, these should just use the *_errno() helper. * Don't report on the errno at all, e.g. in this case shown here.
It seems to me that all of these should be using die_errno(), error_errno() etc.
Or maybe it's the other way around, and we should not rely on the global "errno", but always capture the return value, and give that to strerror() (or set "errno = ret", and call {die,error,warning}_errno()).
In any case, some low-hanging #leftoverbits there...