Re: [PATCH] transport-helper: check when helpers fail
From: Johannes Sixt <hidden>
Date: 2016-06-15 22:55:05
Am 10/21/2012 21:19, schrieb Felipe Contreras:
quoted hunk ↗ jump to hunk
diff --git a/run-command.c b/run-command.c index 1101ef7..2852e9d 100644 --- a/run-command.c +++ b/run-command.c@@ -559,6 +559,23 @@ int run_command(struct child_process *cmd) return finish_command(cmd); } +int check_command(struct child_process *cmd) +{ + int status; + pid_t pid; + + pid = waitpid(cmd->pid, &status, WNOHANG); + + if (pid < 0) + return -1; + if (WIFSIGNALED(status)) + return WTERMSIG(status); + if (WIFEXITED(status)) + return WEXITSTATUS(status); + + return 0; +} +
In this form, the function is not suitable as a public run-command API: If
the child did exit, it does not allow finish_command() to do its thing.
The only thing the caller of this function can do is to die() if it
returns non-zero. It doesn't report treat error cases in the same way as
wait_or_whine().
I would expect the function to be usable in this way:
start_command(&proc);
loop {
if (check_command(&proc))
break;
}
finish_command(&proc);
but it would require a bit more work because it would have to cache the
exit status in struct child_process.
BTW, you should check for return value 0 from waitpid() explicitly.
Another thought: In your use-case, isn't it so that it would be an error
that the process exited for whatever reason? I.e., even if it exited with
code 0 ("success"), it would be an error because it violated the protocol?
-- Hannes