[PATCH v3 12/17] xfs_scrub: report optional features in version string

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Ted Ts'o reported brittleness in the fstests logic in generic/45[34] to
detect whether or not xfs_scrub is capable of detecting Unicode mischief
in directory and xattr names.  This is a compile-time feature, since we
do not assume that all distros will want to ship xfsprogs with libicu.

Rather than relying on ldd tests (which don't work at all if xfs_scrub
is compiled statically), let's have -V print whether or not the feature
is built into the tool.  Phase 5 still requires the presence of "UTF-8"
in LC_MESSAGES to enable Unicode confusable detection; this merely makes
the feature easier to discover.

Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
v2: correct the name of the reporter
v3: only report if -VV specified
---
 scrub/xfs_scrub.c |   26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/scrub/xfs_scrub.c b/scrub/xfs_scrub.c
index bc2e84a7..41839c26 100644
--- a/scrub/xfs_scrub.c
+++ b/scrub/xfs_scrub.c
@@ -582,6 +582,13 @@ report_outcome(
 	}
 }
 
+/* Compile-time features discoverable via version strings */
+#ifdef HAVE_LIBICU
+# define XFS_SCRUB_HAVE_UNICODE	"+"
+#else
+# define XFS_SCRUB_HAVE_UNICODE	"-"
+#endif
+
 int
 main(
 	int			argc,
@@ -592,6 +599,7 @@ main(
 	char			*mtab = NULL;
 	FILE			*progress_fp = NULL;
 	struct fs_path		*fsp;
+	int			vflag = 0;
 	int			c;
 	int			fd;
 	int			ret = SCRUB_RET_SUCCESS;
@@ -670,10 +678,8 @@ main(
 			verbose = true;
 			break;
 		case 'V':
-			fprintf(stdout, _("%s version %s\n"), progname,
-					VERSION);
-			fflush(stdout);
-			return SCRUB_RET_SUCCESS;
+			vflag++;
+			break;
 		case 'x':
 			scrub_data = true;
 			break;
@@ -682,6 +688,18 @@ main(
 		}
 	}
 
+	if (vflag) {
+		if (vflag == 1)
+			fprintf(stdout, _("%s version %s\n"),
+					progname, VERSION);
+		else
+			fprintf(stdout, _("%s version %s %sUnicode\n"),
+					progname, VERSION,
+					XFS_SCRUB_HAVE_UNICODE);
+		fflush(stdout);
+		return SCRUB_RET_SUCCESS;
+	}
+
 	/* Override thread count if debugger */
 	if (debug_tweak_on("XFS_SCRUB_THREADS")) {
 		unsigned int	x;