cf-check: Fix segfault on missing state directory

[btriller]

No description provided.

[cf-bottom]

Thanks for submitting a PR! Maybe @larsewi can review this?

[larsewi]

Thanks @btriller 🚀 Although it should probably return NULL so that the failure can be detected by the callers.

[larsewi]

Suggested change

	files = SeqNew(1, NULL);
	return NULL;

[btriller]

Ah, didn't check for other uses of argv_to_lmdb_files(). Will squash if updated change is ok. I guess, leaking sequence is no real issue on argv_to_lmdb_files() usage?

% valgrind --leak-check=full ./cf-check/cf-check dump
==1477289== Memcheck, a memory error detector
==1477289== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==1477289== Using Valgrind-3.24.0 and LibVEX; rerun with -h for copyright info
==1477289== Command: ./cf-check/cf-check dump
==1477289==
    info: No filenames specified, defaulting to .lmdb files in /home/btriller/.cfagent/state
No database files to dump.
==1477289==
==1477289== HEAP SUMMARY:
==1477289==     in use at exit: 136 bytes in 3 blocks
==1477289==   total heap usage: 34 allocs, 31 frees, 53,996 bytes allocated
==1477289==
==1477289== 112 (32 direct, 80 indirect) bytes in 1 blocks are definitely lost in loss record 3 of 3
==1477289==    at 0x4844818: malloc (vg_replace_malloc.c:446)
==1477289==    by 0x11209C: xmalloc (alloc.c:42)
==1477289==    by 0x11BBA7: SeqNew (sequence.c:32)
==1477289==    by 0x112AE3: ListDir (file_lib.c:634)
==1477289==    by 0x10F750: default_lmdb_files (utilities.c:14)
==1477289==    by 0x10F4C7: dump_main (dump.c:556)
==1477289==    by 0x10CD49: main (cf-check.c:209)
==1477289==
==1477289== LEAK SUMMARY:
==1477289==    definitely lost: 32 bytes in 1 blocks
==1477289==    indirectly lost: 80 bytes in 1 blocks
==1477289==      possibly lost: 0 bytes in 0 blocks
==1477289==    still reachable: 24 bytes in 1 blocks
==1477289==         suppressed: 0 bytes in 0 blocks
==1477289== Reachable blocks (those to which a pointer was found) are not shown.
==1477289== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==1477289==
==1477289== For lists of detected and suppressed errors, rerun with: -s
==1477289== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

[larsewi]

This is good. However, I still think argv_to_lmdb_files should return NULL on failure, so that the call sites can handle it.

The memory leak is preexisting. But, feel free to fix it too, preferably in a separate commit.

Thanks again!

[larsewi]

The argv_to_lmdb_files already logs an error. Hence, there is no need to log another one here.

Suggested change

	if (files == NULL || SeqLength(files) == 0)
	{
	printf("No database files to dump.\n");
	return 1;
	}
	if (files == NULL || SeqLength(files) == 0)
	{
	return 1;
	}