Re: [Tarantool-patches] [PATCH v2 1/3] sql: add missing diag_set on failure when working with files inside SQL module

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Hi! Thanks for the patchset!

On 11.12.2020 15:49, Leonid Vasiliev wrote:
> From: Mergen Imeev <imeevma@gmail.com>
> 
> SQL module didn't set an error in the diagnostics area on a file
> operation failure. This could lead to a crash like in #5537.
> 
> Part of #5537
> ---
>  src/box/sql/os_unix.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/src/box/sql/os_unix.c b/src/box/sql/os_unix.c
> index b351c55..557d709 100644
> --- a/src/box/sql/os_unix.c
> +++ b/src/box/sql/os_unix.c
> @@ -159,14 +159,17 @@ robust_open(const char *z, int f, mode_t m)
>  		if (fd < 0) {
>  			if (errno == EINTR)
>  				continue;
> +			diag_set(SystemError, strerror(errno));
>  			break;

SystemError already reports strerror() in ::log() method.
I don't think you need to duplicate it. Better add a proper
description. For example, the path. Grep "diag_set(SystemError"
in our project and see other usages which try to provide
more info. The same in other places.

>  		}
>  		if (fd >= SQL_MINIMUM_FILE_DESCRIPTOR)
>  			break;
>  		close(fd);
>  		fd = -1;
> -		if (open("/dev/null", f, m) < 0)
> +		if (open("/dev/null", f, m) < 0) {
> +			diag_set(SystemError, strerror(errno));
>  			break;
> +		}
>  	}
>  	if (fd >= 0) {
>  		if (m != 0) {
> @@ -831,8 +834,10 @@ seekAndWriteFd(int fd,		/* File descriptor to write to */
>  		rc = write(fd, pBuf, nBuf);
>  	} while (rc < 0 && errno == EINTR);
>  
> -	if (rc < 0)
> +	if (rc < 0) {
> +		diag_set(SystemError, strerror(errno));
>  		*piErrno = errno;
> +	}
>  	return rc;
>  }
>  
>