Subject: Re: [updated patch v3 1/2] Report exec errors from run-command

From: Johannes Sixt <[email-masked]>
Date: Thu, 31 Dec 2009 20:03:04 +0100

Ilari Liusvaara schrieb:
> +static inline void force_close(int fd)
> +{
> +	/*
> +	 * The close is deemed success or failed in non-transient way if
> +	 * close() suceeds, returns EBADF or error other than EINTR or
> +	 * EAGAIN.
> +	 */
> +	while (close(fd) < 0 && errno != EBADF)
> +		if(errno != EINTR && errno != EAGAIN)
> +			break;

You are constantly ignoring proposals to iterate only on EINTR and EAGAIN, 
but do not make an argument why you do otherwise. Did I miss something?

>  	cmd->pid = fork();
> -	if (!cmd->pid) {
> +	if (cmd->pid > 0) {
> +		int r = 0, ret;
> +		force_close(report_pipe[1]);
> +read_again:
> +		if (report_pipe[0] >= 0)
> +			r = read(report_pipe[0], &ret, sizeof(ret));
> +		if (r < 0 && (errno == EAGAIN || errno == EINTR ||
> +			errno == EWOULDBLOCK))
> +			goto read_again;
> +		else if (r < 0)
> +			warning("Can't read exec status report: %s\n",
> +				strerror(errno));
> +		else if (r == 0)
> +			;
> +		else if (r < sizeof(ret)) {
> +			warning("Received incomplete exec status report.\n");
> +			errno = EBADMSG;
> +		} else {
> +			failed_errno = ret;
> +			/*
> +			 * Clean up the process that did the failed execution
> +			 * so no zombies remain.
> +			 */
> +			if(waitpid(cmd->pid, &ret, 0) < 0 && errno == EINTR)
> +				/* Nothing. */ ;
> +			cmd->pid = -1;

As per Documentation/technical/api-run-command.txt, you should write an 
error here, except if (failed_errno==ENOENT && cmd->silent_exec_failure!=0).

> +test_expect_success "reporting ENOENT" \
> +"test-run-command 1"

I wonder what this parameter "1" is good for...

-- Hannes