shell: clarify help text of CONFIG_{SH,BASH}_IS_* options

[oweals/busybox.git] / libbb / find_mount_point.c

diff --git a/libbb/find_mount_point.c b/libbb/find_mount_point.c
index cb00b9806f08200373804693e27805da493a6c02..9676b5f52c6cf8b8da4937f713a7de007c3df9bc 100644 (file)
--- a/libbb/find_mount_point.c
+++ b/libbb/find_mount_point.c
@@ -4,7 +4,7 @@
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 #include "libbb.h"
@@ -17,37 +17,53 @@
  * Given any other file (or directory), find the mount table entry for its
  * filesystem.
  */
-struct mntent *find_mount_point(const char *name, const char *table)
+struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too)
 {
        struct stat s;
-       dev_t mountDevice;
-       FILE *mountTable;
+       FILE *mtab_fp;
        struct mntent *mountEntry;
+       dev_t devno_of_name;
+       bool block_dev;
 
        if (stat(name, &s) != 0)
-               return 0;
+               return NULL;
 
-       if ((s.st_mode & S_IFMT) == S_IFBLK)
-               mountDevice = s.st_rdev;
-       else
-               mountDevice = s.st_dev;
+       devno_of_name = s.st_dev;
+       block_dev = 0;
+       /* Why S_ISCHR? - UBI volumes use char devices, not block */
+       if (S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode)) {
+               devno_of_name = s.st_rdev;
+               block_dev = 1;
+       }
 
+       mtab_fp = setmntent(bb_path_mtab_file, "r");
+       if (!mtab_fp)
+               return NULL;
 
-       mountTable = setmntent(table ? table : bb_path_mtab_file, "r");
-       if (!mountTable)
-               return 0;
+       while ((mountEntry = getmntent(mtab_fp)) != 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 (ENABLE_FEATURE_SKIP_ROOTFS && strcmp(mountEntry->mnt_fsname, "rootfs") == 0)
+                       continue;
 
-       while ((mountEntry = getmntent(mountTable)) != 0) {
                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. */
+
+               if (!(subdir_too || block_dev))
+                       continue;
+
+               /* Is device's dev_t == name's dev_t? */
+               if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == devno_of_name)
                        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 == devno_of_name)
                        break;
        }
-       endmntent(mountTable);
+       endmntent(mtab_fp);
+
        return mountEntry;
 }