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 444770d27..123d1de74 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 34b015090..d95aff39d 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 835beb20c..6f4c547e5 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 4cd6b1618..12b2cfce4 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 34b09cecc..838adf2e7 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 0c33c1b02..ca0b17efe 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 2666132f9..18512a395 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 98a089502..8c6078d7b 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