[LTP] [PATCH v3 07/12] syscalls/quotactl08: Test quoatctl01 but quota info hidden in filesystem

[xuyang2018.jy@fujitsu.com]

Hi Cyril
> Hi!
>> +	f = SAFE_POPEN("mkfs.ext4 -V 2>&1", "r");
>> +	rc = fscanf(f, "mke2fs %d.%d.%d",&major,&minor,&patch);
>> +	if (rc != 3)
>> +		tst_res(TWARN, "Unable parse version number");
>> +	else if (major * 10000 + minor * 100 + patch<  14300)
>> +		tst_brk(TCONF, "Test needs mkfs.ext4>= 1.43 for quota option, test skipped");
>> +	pclose(f);
>
> Ideally this should be added to the .needs_cmds instead so that we get
> the minimal version in the test metadata too.
Good suggestion, I am looking your code. But As my commit log said,  add 
a lib mkfs.ext4 version check after this quotactl patchset are merged.

Then we can add this version check and make use it for not only 
quotactl04,08,09 case but also for statx05.c.

Best Regards
Yang Xu
>
> I wonder how this should be done.
>
> One possibility would be adding support for version in the needs_cmds
> strings as:
>
> "mkfs.ext4>= 1.43"
>
> Then we would have to add a table of version checks to the library as
> well so that we could lookup a function based on the command name.
>
> Something as:
>
> static long mkfs_ext4_version_parser(void)
> {
> 	f = SAFE_POPEN("mkfs.ext4 -V 2>&1", "r");
> 	rc = fscanf(f, "mke2fs %d.%d.%d",&major,&minor,&patch);
> 	pclose(f);
> 	if (rc != 3) {
> 		tst_res(TWARN, "Unable to parse mkfs.ext4 version");
> 		return -1;
> 	}
>
> 	return major * 10000 * minor * 100 + patch;
> }
>
> static struct version_parser {
> 	const char *name,
> 	long (*parser)(void);
> } version_parsers[] = {
> 	{.cmd = "mkfs.ext4", .parser = mkfs_ext4_version_parser},
> 	{},
> };
>
> Then the library would do:
>
> 	struct version_parser *p;
> 	size_t cmd_len;
> 	long version;
> 	char *str, *version;
>
> 	str = strchr(cmd, ' ');
> 	if (!str)
> 		return;
>
> 	version = strchr(str, ' ');
> 	if (!version)
> 		tst_brk(TBROK, "Missing version in %s", cmd);
>
> 	//TODO: check that the string between str and version is a
> 	//correct operator
>
> 	cmd_len = str - cmd;
>
> 	for (p = *version_parsers; *p; p++) {
> 		if (strlen(p->name) != cmd_len)
> 			continue;
>
> 		if (!strncmp(p->name, cmd, cmd_len))
> 			break;
> 	}
>
> 	if (!p->name)
> 		tst_brk(TBROK, "No version parser for %s implemented!");
>
> 	long ver = p->parser();
> 	if (ver<  0)
> 		tst_brk(TBROK, "Failed to parse %s version", p->name);
>
> 	/* now we have to parse the version from the version variable
> 	 * and compare it with the ver variable */
>