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

[Sergey Ostanevich <sergos@tarantool.org>]

Thanks for the patch, LGTM.

Sergos

> On 14 Dec 2020, at 18:49, Leonid Vasiliev <lvasiliev@tarantool.org> wrote:
> 
> Hi! Thank you for the review.
> 
> On 13.12.2020 21:30, Vladislav Shpilevoy wrote:
>> 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.
> 
> I thought about adding more info to the error, but it seems to me that
> only "trace" is useful here. I do not mind your proposal. See full diff
> at the end of the letter
> 
>>>  		}
>>>  		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;
>>>  }
>>>  
> 
> 
> 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..ea7d3cc 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, "failed to open file '%s'", z);
> 			break;
> 		}
> 		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, "failed to open '/dev/null'");
> 			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, "failed to write %i bytes to file", nBuf);
> 		*piErrno = errno;
> +	}
> 	return rc;
> }