[PATCH 3/3] xfsprogs: misc uClibc patches: use statfs() instead of ustat()

[Joshua Kinard]

From: Joshua Kinard <kumba at gentoo.org>

uClibc doesn't provide the ustat() call and statfs() should be used instead.
Patch was previously sent upstream, but rejected because ustat() checks for the
block device being mounted anywhere.  This version of the patch takes care of
that check, as well as replacing ustat() with statfs().

Refer to Gentoo Bug #477758:
https://bugs.gentoo.org/show_bug.cgi?id=477758

Signed-off-by: Joshua Kinard <kumba at gentoo.org>
Suggested-by: René Rhéaume <rene.rheaume at gmail.com>
---
 libxfs/linux.c |   35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff -Naurp xfsprogs-4.3.0.orig/libxfs/linux.c xfsprogs-4.3.0/libxfs/linux.c
--- xfsprogs-4.3.0.orig/libxfs/linux.c	2015-08-03 00:39:42.000000000 +0000
+++ xfsprogs-4.3.0/libxfs/linux.c	2016-01-01 10:49:06.272229000 +0000
@@ -20,7 +20,7 @@
 #include <mntent.h>
 #include <sys/stat.h>
 #undef ustat
-#include <sys/ustat.h>
+#include <sys/statvfs.h>
 #include <sys/mount.h>
 #include <sys/ioctl.h>
 #include <sys/sysinfo.h>
@@ -51,9 +51,11 @@ static int max_block_alignment;
 int
 platform_check_ismounted(char *name, char *block, struct stat64 *s, int verbose)
 {
-	/* Pad ust; pre-2.6.28 linux copies out too much in 32bit compat mode */
-	struct ustat	ust[2];
+	struct statfs	ust;
 	struct stat64	st;
+	char		mounts[MAXPATHLEN];
+	FILE*		mtab;
+	struct mntent*	mnt;
 
 	if (!s) {
 		if (stat64(block, &st) < 0)
@@ -63,7 +65,32 @@ platform_check_ismounted(char *name, cha
 		s = &st;
 	}
 
-	if (ustat(s->st_rdev, ust) >= 0) {
+	if (strcmp(name, block) == 0) {
+		/* Device node was passed as parameter. Find its mount point */
+		strcpy(mounts, (!access(PROC_MOUNTED, R_OK)) ? PROC_MOUNTED : MOUNTED);
+		mtab = setmntent(mounts, "r");
+		if (mtab == NULL) {
+			if (verbose) {
+				fprintf(stderr, _("%s: %s contains a possibly mounted filesystem\n"), progname, name);
+			}
+			return 1;
+		}
+		else {
+			mnt = getmntent(mtab);
+			while (mnt != NULL) {
+				if (strcmp(block, mnt->mnt_fsname) == 0) {
+					if (verbose) {
+						 fprintf(stderr, _("%s: %s contains a mounted filesystem\n"), progname, name);
+					}
+					endmntent(mtab);
+					return 1;
+				}
+				mnt = getmntent(mtab);
+			}
+			endmntent(mtab);
+		}
+	}
+	else if (statfs(name, &ust) >= 0) {
 		if (verbose)
 			fprintf(stderr,
 				_("%s: %s contains a mounted filesystem\n"),