Re: [PATCH] debugfs/set_fields: fix several errors and add assertions

[Andreas Dilger <adilger@dilger.ca>]

On Feb 24, 2015, at 9:24 PM, Darrick J. Wong <darrick.wong@oracle.com> wrote:
> 
> On Tue, Feb 24, 2015 at 03:46:11PM +0300, Konstantin Khlebnikov wrote:
>> Fix copy-n-paste errors:
>> * remove duplicate "lastcheck" and "min_extra_isize"
>> * fix pointer for "first_error_line" and "last_error_line"
>> * remove superblock field "inodes_count" from inode fields
>> * add null-termination for mmp_fields
>> 
>> Add assertions for catching such errors in the future.
>> Mark true aliases with flag "FLAG_ALIAS" and suppress assert for them.
>> 
>> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
>> ---
>> debugfs/set_fields.c |   65 ++++++++++++++++++++++++++++++++++++++++++--------
>> 1 file changed, 55 insertions(+), 10 deletions(-)
>> 
>> diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c
>> index 60695ad..1af7d0f 100644
>> --- a/debugfs/set_fields.c
>> +++ b/debugfs/set_fields.c
>> @@ -30,6 +30,7 @@
>> #ifdef HAVE_ERRNO_H
>> #include <errno.h>
>> #endif
>> +#include <assert.h>
>> #if HAVE_STRINGS_H
>> #include <strings.h>
>> #endif
>> @@ -50,6 +51,7 @@ static ext2_ino_t set_ino;
>> static int array_idx;
>> 
>> #define FLAG_ARRAY	0x0001
>> +#define FLAG_ALIAS	0x0002	/* Data intersects with other field */
>> 
>> struct field_set_info {
>> 	const char	*name;
>> @@ -110,7 +112,6 @@ static struct field_set_info super_fields[] = {
>> 	{ "uuid", &set_sb.s_uuid, NULL, 16, parse_uuid },
>> 	{ "volume_name",  &set_sb.s_volume_name, NULL, 16, parse_string },
>> 	{ "last_mounted",  &set_sb.s_last_mounted, NULL, 64, parse_string },
>> -	{ "lastcheck",  &set_sb.s_lastcheck, NULL, 4, parse_uint },
>> 	{ "algorithm_usage_bitmap", &set_sb.s_algorithm_usage_bitmap, NULL,
>> 		  4, parse_uint },
>> 	{ "prealloc_blocks", &set_sb.s_prealloc_blocks, NULL, 1, parse_uint },
>> @@ -135,7 +136,6 @@ static struct field_set_info super_fields[] = {
>> 	{ "want_extra_isize", &set_sb.s_want_extra_isize, NULL, 2, parse_uint },
>> 	{ "flags", &set_sb.s_flags, NULL, 4, parse_uint },
>> 	{ "raid_stride", &set_sb.s_raid_stride, NULL, 2, parse_uint },
>> -	{ "min_extra_isize", &set_sb.s_min_extra_isize, NULL, 4, parse_uint },
>> 	{ "mmp_interval", &set_sb.s_mmp_update_interval, NULL, 2, parse_uint },
>> 	{ "mmp_block", &set_sb.s_mmp_block, NULL, 8, parse_uint },
>> 	{ "raid_stripe_width", &set_sb.s_raid_stripe_width, NULL, 4, parse_uint },
>> @@ -159,19 +159,18 @@ static struct field_set_info super_fields[] = {
>> 	{ "first_error_ino", &set_sb.s_first_error_ino, NULL, 4, parse_uint },
>> 	{ "first_error_block", &set_sb.s_first_error_block, NULL, 8, parse_uint },
>> 	{ "first_error_func", &set_sb.s_first_error_func, NULL, 32, parse_string },
>> -	{ "first_error_line", &set_sb.s_first_error_ino, NULL, 4, parse_uint },
>> +	{ "first_error_line", &set_sb.s_first_error_line, NULL, 4, parse_uint },
>> 	{ "last_error_time", &set_sb.s_last_error_time, NULL, 4, parse_time },
>> 	{ "last_error_ino", &set_sb.s_last_error_ino, NULL, 4, parse_uint },
>> 	{ "last_error_block", &set_sb.s_last_error_block, NULL, 8, parse_uint },
>> 	{ "last_error_func", &set_sb.s_last_error_func, NULL, 32, parse_string },
>> -	{ "last_error_line", &set_sb.s_last_error_ino, NULL, 4, parse_uint },
>> +	{ "last_error_line", &set_sb.s_last_error_line, NULL, 4, parse_uint },
>> 	{ "encrypt_algos", &set_sb.s_encrypt_algos, NULL, 1, parse_uint,
>> 	  FLAG_ARRAY, 4 },
>> 	{ 0, 0, 0, 0 }
>> };
>> 
>> static struct field_set_info inode_fields[] = {
>> -	{ "inodes_count", &set_sb.s_inodes_count, NULL, 4, parse_uint },
>> 	{ "mode", &set_inode.i_mode, NULL, 2, parse_uint },
>> 	{ "uid", &set_inode.i_uid, &set_inode.osd2.linux2.l_i_uid_high,
>> 		2, parse_uint },
>> @@ -189,7 +188,8 @@ static struct field_set_info inode_fields[] = {
>> 	{ "flags", &set_inode.i_flags, NULL, 4, parse_uint },
>> 	{ "version", &set_inode.osd1.linux1.l_i_version,
>> 		&set_inode.i_version_hi, 4, parse_uint },
>> -	{ "translator", &set_inode.osd1.hurd1.h_i_translator, NULL, 4, parse_uint },
>> +	{ "translator", &set_inode.osd1.hurd1.h_i_translator, NULL,
>> +		4, parse_uint, FLAG_ALIAS },
>> 	{ "block", &set_inode.i_block[0], NULL, 4, parse_uint, FLAG_ARRAY,
>> 	  EXT2_NDIR_BLOCKS },
>> 	{ "block[IND]", &set_inode.i_block[EXT2_IND_BLOCK], NULL, 4, parse_uint },
>> @@ -199,14 +199,14 @@ static struct field_set_info inode_fields[] = {
>> 	/* Special case: i_file_acl_high is 2 bytes */
>> 	{ "file_acl", &set_inode.i_file_acl, 
>> 		&set_inode.osd2.linux2.l_i_file_acl_high, 6, parse_uint },
>> -	{ "dir_acl", &set_inode.i_dir_acl, NULL, 4, parse_uint },
>> +	{ "dir_acl", &set_inode.i_dir_acl, NULL, 4, parse_uint, FLAG_ALIAS },
>> 	{ "faddr", &set_inode.i_faddr, NULL, 4, parse_uint },
>> -	{ "frag", &set_inode.osd2.hurd2.h_i_frag, NULL, 1, parse_uint },
>> +	{ "frag", &set_inode.osd2.hurd2.h_i_frag, NULL, 1, parse_uint, FLAG_ALIAS },
>> 	{ "fsize", &set_inode.osd2.hurd2.h_i_fsize, NULL, 1, parse_uint },
>> 	{ "checksum", &set_inode.osd2.linux2.l_i_checksum_lo, 
>> 		&set_inode.i_checksum_hi, 2, parse_uint },
>> 	{ "author", &set_inode.osd2.hurd2.h_i_author, NULL,
>> -		4, parse_uint },
>> +		4, parse_uint, FLAG_ALIAS },
>> 	{ "extra_isize", &set_inode.i_extra_isize, NULL,
>> 		2, parse_uint },
>> 	{ "ctime_extra", &set_inode.i_ctime_extra, NULL,
>> @@ -262,7 +262,8 @@ static struct field_set_info ext4_bg_fields[] = {
>> };
>> 
>> static struct field_set_info mmp_fields[] = {
>> -	{ "clear", &set_mmp.mmp_magic, NULL, sizeof(set_mmp), parse_mmp_clear },
>> +	{ "clear", &set_mmp.mmp_magic, NULL, sizeof(set_mmp),
>> +		parse_mmp_clear, FLAG_ALIAS },
>> 	{ "magic", &set_mmp.mmp_magic, NULL, 4, parse_uint },
>> 	{ "seq", &set_mmp.mmp_seq, NULL, 4, parse_uint },
>> 	{ "time", &set_mmp.mmp_time, NULL, 8, parse_uint },
>> @@ -272,8 +273,52 @@ static struct field_set_info mmp_fields[] = {
>> 		parse_string },
>> 	{ "check_interval", &set_mmp.mmp_check_interval, NULL, 2, parse_uint },
>> 	{ "checksum", &set_mmp.mmp_checksum, NULL, 4, parse_uint },
>> +	{ 0, 0, 0, 0 }
> 
> Looks good so far.
> 
>> };
>> 
>> +static void do_verify_field_set_info(struct field_set_info *fields,
>> +		const void *data, size_t size)
>> +{
>> +	struct field_set_info *ss, *ss2;
>> +	const char *begin = (char *)data;
>> +	const char *end = begin + size;
>> +
>> +	for (ss = fields ; ss->name ; ss++) {
>> +		const char *ptr;
>> +
>> +		/* Check pointers */
>> +		ptr = ss->ptr;
>> +		assert(!ptr || (ptr >= begin && ptr < end));
>> +		ptr = ss->ptr2;
>> +		assert(!ptr || (ptr >= begin && ptr < end));
>> +
>> +		/* Check function */
>> +		assert(ss->func);
>> +
>> +		for (ss2 = fields ; ss2 != ss ; ss2++) {
>> +			/* Check duplicate names */
>> +			assert(strcmp(ss->name, ss2->name));
>> +
>> +			if (ss->flags & FLAG_ALIAS || ss2->flags & FLAG_ALIAS)
>> +				continue;
>> +			/* Check false aliases, might be copy-n-paste error */
>> +			assert(!ss->ptr || (ss->ptr != ss2->ptr &&
>> +					    ss->ptr != ss2->ptr2));
>> +			assert(!ss->ptr2 || (ss->ptr2 != ss2->ptr &&
>> +					     ss->ptr2 != ss2->ptr2));
>> +		}
>> +	}
>> +}
>> +
>> +static __attribute__((constructor)) void verify_field_set_info(void)
>> +{
>> +	do_verify_field_set_info(super_fields, &set_sb, sizeof(set_sb));
>> +	do_verify_field_set_info(inode_fields, &set_inode, sizeof(set_inode));
>> +	do_verify_field_set_info(ext2_bg_fields, &set_gd, sizeof(set_gd));
>> +	do_verify_field_set_info(ext4_bg_fields, &set_gd4, sizeof(set_gd4));
>> +	do_verify_field_set_info(mmp_fields, &set_mmp, sizeof(set_mmp));
>> +}
> 
> This ought to be run along with the 'make check' testcases, since they're
> already looking for errors there.
> 
> Also, does running this on /every/ debugfs invocation slow down startup
> noticeably?  Just idle curiosity. :)

Many sources in e2fsprogs have compile-time test code that can be
used to test something like this.  They are enabled under "#ifdef DEBUG",
for example lib/ext2fs/icount.c is built as "tst_icount" with -DDEBUG
in order to test its functionality with "make check" rather than running
this test for every normal invocation:

tst_icount: $(srcdir)/icount.c $(STATIC_LIBEXT2FS) $(DEPSTATIC_LIBCOM_ERR)
        $(E) "  LD $@"
        $(Q) $(CC) -o tst_icount $(srcdir)/icount.c -DDEBUG $(ALL_CFLAGS) \
                $(STATIC_LIBEXT2FS) $(STATIC_LIBCOM_ERR) $(SYSLIBS)

In e2fsck/problem.c is a similar functionality under "#ifdef UNITTEST" to
build the tst_problem binary for "make check" to verify that there are no
duplicate problem codes defined.

I'm not sure if Ted has a preference between DEBUG and UNITTEST, but that
is definitely preferable to running this for every debugfs invocation.

Cheers, Andreas