df: fix "df /"

also, clean up mount checks in mkfs/fsck.

function                                             old     new   delta
find_mount_point                                     243     261     +18
sha1_process_block64                                 497     510     +13
find_main                                            436     444      +8
display_speed                                         85      90      +5
df_main                                              795     793      -2
parse_command                                       1463    1460      -3
static.ignored_mounts                                  8       -      -8
mkfs_minix_main                                     2962    2937     -25
fsck_minix_main                                     3065    2970     -95
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 4/4 up/down: 44/-133)           Total: -89 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

8 files changed, 47 insertions, 54 deletions

diff --git a/archival/libunarchive/data_extract_all.c b/archival/libunarchive/data_extract_all.c
index 444770d..123d1de 100644
--- a/archival/libunarchive/data_extract_all.c
+++ b/archival/libunarchive/data_extract_all.c
@@ -21,7 +21,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
 	/* Check if the file already exists */
 	if (archive_handle->ah_flags & ARCHIVE_EXTRACT_UNCONDITIONAL) {
 		/* Remove the entry if it exists */
-		if (((file_header->mode & S_IFMT) != S_IFDIR)
+		if ((!S_ISDIR(file_header->mode))
 		 && (unlink(file_header->name) == -1)
 		 && (errno != ENOENT)
 		) {
@@ -132,7 +132,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
 #endif
 			lchown(file_header->name, file_header->uid, file_header->gid);
 	}
-	if ((file_header->mode & S_IFMT) != S_IFLNK) {
+	if (S_ISLNK(file_header->mode)) {
 		/* uclibc has no lchmod, glibc is even stranger -
 		 * it has lchmod which seems to do nothing!
 		 * so we use chmod... */
diff --git a/coreutils/df.c b/coreutils/df.c
index 34b0150..d95aff3 100644
--- a/coreutils/df.c
+++ b/coreutils/df.c
@@ -44,7 +44,6 @@ int df_main(int argc, char **argv)
 	FILE *mount_table;
 	struct mntent *mount_entry;
 	struct statfs s;
-	static const char ignored_mounts[] ALIGN1 = "rootfs\0";
 
 	enum {
 		OPT_KILO  = (1 << 0),
@@ -120,7 +119,7 @@ int df_main(int argc, char **argv)
 			mount_point = *argv++;
 			if (!mount_point)
 				break;
-			mount_entry = find_mount_point(mount_point, bb_path_mtab_file);
+			mount_entry = find_mount_point(mount_point);
 			if (!mount_entry) {
 				bb_error_msg("%s: can't find mount point", mount_point);
  set_error:
@@ -154,8 +153,8 @@ int df_main(int argc, char **argv)
 						) / (blocks_used + s.f_bavail);
 			}
 
-			/* GNU coreutils 6.10 skip certain mounts, try to be compatible.  */
-			if (index_in_strings(device, ignored_mounts) != -1)
+			/* GNU coreutils 6.10 skips certain mounts, try to be compatible.  */
+			if (strcmp(device, "rootfs") == 0)
 				continue;
 
 #ifdef WHY_WE_DO_IT_FOR_DEV_ROOT_ONLY
diff --git a/include/libbb.h b/include/libbb.h
index 835beb2..6f4c547 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -986,7 +986,7 @@ extern void run_applet_no_and_exit(int a, char **argv) NORETURN FAST_FUNC;
 
 #ifdef HAVE_MNTENT_H
 extern int match_fstype(const struct mntent *mt, const char *fstypes) FAST_FUNC;
-extern struct mntent *find_mount_point(const char *name, const char *table) FAST_FUNC;
+extern struct mntent *find_mount_point(const char *name) FAST_FUNC;
 #endif
 extern void erase_mtab(const char * name) FAST_FUNC;
 extern unsigned int tty_baud_to_value(speed_t speed) FAST_FUNC;
diff --git a/libbb/find_mount_point.c b/libbb/find_mount_point.c
index 4cd6b16..12b2cfc 100644
--- a/libbb/find_mount_point.c
+++ b/libbb/find_mount_point.c
@@ -17,7 +17,7 @@
  * Given any other file (or directory), find the mount table entry for its
  * filesystem.
  */
-struct mntent* FAST_FUNC find_mount_point(const char *name, const char *table)
+struct mntent* FAST_FUNC find_mount_point(const char *name)
 {
 	struct stat s;
 	dev_t mountDevice;
@@ -25,27 +25,35 @@ struct mntent* FAST_FUNC find_mount_point(const char *name, const char *table)
 	struct mntent *mountEntry;
 
 	if (stat(name, &s) != 0)
-		return 0;
+		return NULL;
 
-	if ((s.st_mode & S_IFMT) == S_IFBLK)
+	if (S_ISBLK(s.st_mode))
 		mountDevice = s.st_rdev;
 	else
 		mountDevice = s.st_dev;
 
 
-	mountTable = setmntent(table ? table : bb_path_mtab_file, "r");
+	mountTable = setmntent(bb_path_mtab_file, "r");
 	if (!mountTable)
 		return 0;
 
-	while ((mountEntry = getmntent(mountTable)) != 0) {
+	while ((mountEntry = getmntent(mountTable)) != NULL) {
+		/* rootfs mount in Linux 2.6 exists always,
+		 * and it makes sense to always ignore it.
+		 * Otherwise people can't reference their "real" root! */
+		if (strcmp(mountEntry->mnt_fsname, "rootfs") == 0)
+			continue;
+
 		if (strcmp(name, mountEntry->mnt_dir) == 0
 		 || strcmp(name, mountEntry->mnt_fsname) == 0
 		) { /* String match. */
 			break;
 		}
-		if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == mountDevice)	/* Match the device. */
+		/* Match the device. */
+		if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == mountDevice)
 			break;
-		if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == mountDevice)	/* Match the directory's mount point. */
+		/* Match the directory's mount point. */
+		if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == mountDevice)
 			break;
 	}
 	endmntent(mountTable);
diff --git a/loginutils/getty.c b/loginutils/getty.c
index 34b09ce..838adf2 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -239,7 +239,7 @@ static void open_tty(const char *tty)
 //		cur_dir_fd = xopen(".", O_DIRECTORY | O_NONBLOCK);
 //		xchdir("/dev");
 //		xstat(tty, &st);
-//		if ((st.st_mode & S_IFMT) != S_IFCHR)
+//		if (!S_ISCHR(st.st_mode))
 //			bb_error_msg_and_die("%s: not a character device", tty);
 
 		if (tty[0] != '/')
diff --git a/util-linux/fsck_minix.c b/util-linux/fsck_minix.c
index 0c33c1b..ca0b17e 100644
--- a/util-linux/fsck_minix.c
+++ b/util-linux/fsck_minix.c
@@ -374,38 +374,28 @@ static int ask(const char *string, int def)
  */
 static void check_mount(void)
 {
-	FILE *f;
-	struct mntent *mnt;
-	int cont;
-	int fd;
-//XXX:FIXME use find_mount_point()
-	f = setmntent(MOUNTED, "r");
-	if (f == NULL)
-		return;
-	while ((mnt = getmntent(f)) != NULL)
-		if (strcmp(device_name, mnt->mnt_fsname) == 0)
-			break;
-	endmntent(f);
-	if (!mnt)
-		return;
-
-	/*
-	 * If the root is mounted read-only, then /etc/mtab is
-	 * probably not correct; so we won't issue a warning based on
-	 * it.
-	 */
-	fd = open(MOUNTED, O_RDWR);
-	if (fd < 0 && errno == EROFS)
-		return;
-	close(fd);
-
-	printf("%s is mounted. ", device_name);
-	cont = 0;
-	if (isatty(0) && isatty(1))
-		cont = ask("Do you really want to continue", 0);
-	if (!cont) {
-		printf("Check aborted\n");
-		exit(EXIT_SUCCESS);
+	if (find_mount_point(device_name)) {
+		int cont;
+#if ENABLE_FEATURE_MTAB_SUPPORT
+		/*
+		 * If the root is mounted read-only, then /etc/mtab is
+		 * probably not correct; so we won't issue a warning based on
+		 * it.
+		 */
+		int fd = open(bb_path_mtab_file, O_RDWR);
+
+		if (fd < 0 && errno == EROFS)
+			return;
+		close(fd);
+#endif
+		printf("%s is mounted. ", device_name);
+		cont = 0;
+		if (isatty(0) && isatty(1))
+			cont = ask("Do you really want to continue", 0);
+		if (!cont) {
+			printf("Check aborted\n");
+			exit(EXIT_SUCCESS);
+		}
 	}
 }
 
diff --git a/util-linux/mkfs_minix.c b/util-linux/mkfs_minix.c
index 2666132..18512a3 100644
--- a/util-linux/mkfs_minix.c
+++ b/util-linux/mkfs_minix.c
@@ -624,7 +624,6 @@ static void setup_tables(void)
 int mkfs_minix_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int mkfs_minix_main(int argc UNUSED_PARAM, char **argv)
 {
-	struct mntent *mp;
 	unsigned opt;
 	char *tmp;
 	struct stat statbuf;
@@ -683,11 +682,8 @@ int mkfs_minix_main(int argc UNUSED_PARAM, char **argv)
 		G.total_blocks = 65535;
 
 	/* Check if it is mounted */
-	mp = find_mount_point(G.device_name, NULL);
-	if (mp && strcmp(G.device_name, mp->mnt_fsname) == 0)
-		bb_error_msg_and_die("%s is mounted on %s; "
-				"refusing to make a filesystem",
-				G.device_name, mp->mnt_dir);
+	if (find_mount_point(G.device_name))
+		bb_error_msg_and_die("can't format mounted filesystem");
 
 	xmove_fd(xopen(G.device_name, O_RDWR), dev_fd);
 	if (fstat(dev_fd, &statbuf) < 0)
diff --git a/util-linux/mkfs_vfat.c b/util-linux/mkfs_vfat.c
index 98a0895..8c6078d 100644
--- a/util-linux/mkfs_vfat.c
+++ b/util-linux/mkfs_vfat.c
@@ -275,7 +275,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 		)
 			bb_error_msg_and_die("will not try to make filesystem on full-disk device (use -I if wanted)");
 		// can't work on mounted filesystems
-		if (find_mount_point(device_name, NULL))
+		if (find_mount_point(device_name))
 			bb_error_msg_and_die("can't format mounted filesystem");
 #endif
 		// get true sector size