Re: [9front] cmd/sort: fix resource leak (patch)

["Igor Boehm" <boehm.igor@gmail.com>]

>Quoth Igor Boehm <boehm.igor@gmail.com>:
>> diff -r 4c6206d69abb sys/src/cmd/sort.c
>> --- a /sys/src/cmd/sort.c	Mon Dec 28 21:21:22 2020 +0100
>> +++ b/sys/src/cmd/sort.c	Tue Dec 29 15:11:29 2020 +0100
>> @@ -209,6 +209,7 @@
>>  			free(ol);
>>  			ol = l;
>>  		}
>> +		free(ol);
>>  		return;
>>  	}
>
>Am I wrong in thinking that we should also be
>freeing ol->key?

Good catch Ori!  Me must have been blind when reviewing this ~SIGH~

Here the reasoning spelled out:

'ol->key' is either heap allocated or set to '0' in function
/sys/src/cmd/sort.c:^buildkey.

The buildkey function is called from /sys/src/cmd/sort.c:^newline and
I believe that on all its exit paths where allocation of the line
succeeds, buildkey() is called.

Hence it is prudent to call free on it as you suggest (if ol->key is
'0' the free() acts as a noop).

So the patch should look like this:

diff -r 4c6206d69abb sys/src/cmd/sort.c
--- a/sys/src/cmd/sort.c	Mon Dec 28 21:21:22 2020 +0100
+++ b/sys/src/cmd/sort.c	Fri Jan 01 20:28:23 2021 +0100
@@ -209,6 +209,8 @@
 			free(ol);
 			ol = l;
 		}
+		free(ol->key);
+		free(ol);
 		return;
 	}