1# 2# For a description of the syntax of this configuration file, 3# see scripts/kbuild/config-language.txt. 4# 5 6menu "Linux System Utilities" 7 8config ACPID 9 bool "acpid" 10 default n 11 help 12 acpid listens to ACPI events coming either in textual form from 13 /proc/acpi/event (though it is marked deprecated it is still widely 14 used and _is_ a standard) or in binary form from specified evdevs 15 (just use /dev/input/event*). 16 17 It parses the event to retrieve ACTION and a possible PARAMETER. 18 It then spawns /etc/acpi/<ACTION>[/<PARAMETER>] either via run-parts 19 (if the resulting path is a directory) or directly as an executable. 20 21 N.B. acpid relies on run-parts so have the latter installed. 22 23config FEATURE_ACPID_COMPAT 24 bool "Accept and ignore redundant options" 25 default n 26 depends on ACPID 27 help 28 Accept and ignore compatibility options -g -m -s -S -v. 29 30config BLKID 31 bool "blkid" 32 default n 33 select VOLUMEID 34 help 35 Lists labels and UUIDs of all filesystems. 36 WARNING: 37 With all submodules selected, it will add ~8k to busybox. 38 39config DMESG 40 bool "dmesg" 41 default n 42 help 43 dmesg is used to examine or control the kernel ring buffer. When the 44 Linux kernel prints messages to the system log, they are stored in 45 the kernel ring buffer. You can use dmesg to print the kernel's ring 46 buffer, clear the kernel ring buffer, change the size of the kernel 47 ring buffer, and change the priority level at which kernel messages 48 are also logged to the system console. Enable this option if you 49 wish to enable the 'dmesg' utility. 50 51config FEATURE_DMESG_PRETTY 52 bool "Pretty dmesg output" 53 default y 54 depends on DMESG 55 help 56 If you wish to scrub the syslog level from the output, say 'Y' here. 57 The syslog level is a string prefixed to every line with the form 58 "<#>". 59 60 With this option you will see: 61 # dmesg 62 Linux version 2.6.17.4 ..... 63 BIOS-provided physical RAM map: 64 BIOS-e820: 0000000000000000 - 000000000009f000 (usable) 65 66 Without this option you will see: 67 # dmesg 68 <5>Linux version 2.6.17.4 ..... 69 <6>BIOS-provided physical RAM map: 70 <6> BIOS-e820: 0000000000000000 - 000000000009f000 (usable) 71 72config FBSET 73 bool "fbset" 74 default n 75 help 76 fbset is used to show or change the settings of a Linux frame buffer 77 device. The frame buffer device provides a simple and unique 78 interface to access a graphics display. Enable this option 79 if you wish to enable the 'fbset' utility. 80 81config FEATURE_FBSET_FANCY 82 bool "Turn on extra fbset options" 83 default n 84 depends on FBSET 85 help 86 This option enables extended fbset options, allowing one to set the 87 framebuffer size, color depth, etc. interface to access a graphics 88 display. Enable this option if you wish to enable extended fbset 89 options. 90 91config FEATURE_FBSET_READMODE 92 bool "Turn on fbset readmode support" 93 default n 94 depends on FBSET 95 help 96 This option allows fbset to read the video mode database stored by 97 default as /etc/fb.modes, which can be used to set frame buffer 98 device to pre-defined video modes. 99 100config FDFLUSH 101 bool "fdflush" 102 default n 103 help 104 fdflush is only needed when changing media on slightly-broken 105 removable media drives. It is used to make Linux believe that a 106 hardware disk-change switch has been actuated, which causes Linux to 107 forget anything it has cached from the previous media. If you have 108 such a slightly-broken drive, you will need to run fdflush every time 109 you change a disk. Most people have working hardware and can safely 110 leave this disabled. 111 112config FDFORMAT 113 bool "fdformat" 114 default n 115 help 116 fdformat is used to low-level format a floppy disk. 117 118config FDISK 119 bool "fdisk" 120 default n 121 help 122 The fdisk utility is used to divide hard disks into one or more 123 logical disks, which are generally called partitions. This utility 124 can be used to list and edit the set of partitions or BSD style 125 'disk slices' that are defined on a hard drive. 126 127config FDISK_SUPPORT_LARGE_DISKS 128 bool "Support over 4GB disks" 129 default y 130 depends on FDISK 131 help 132 Enable this option to support large disks > 4GB. 133 134config FEATURE_FDISK_WRITABLE 135 bool "Write support" 136 default y 137 depends on FDISK 138 help 139 Enabling this option allows you to create or change a partition table 140 and write those changes out to disk. If you leave this option 141 disabled, you will only be able to view the partition table. 142 143config FEATURE_AIX_LABEL 144 bool "Support AIX disklabels" 145 default n 146 depends on FDISK && FEATURE_FDISK_WRITABLE 147 help 148 Enabling this option allows you to create or change AIX disklabels. 149 Most people can safely leave this option disabled. 150 151config FEATURE_SGI_LABEL 152 bool "Support SGI disklabels" 153 default n 154 depends on FDISK && FEATURE_FDISK_WRITABLE 155 help 156 Enabling this option allows you to create or change SGI disklabels. 157 Most people can safely leave this option disabled. 158 159config FEATURE_SUN_LABEL 160 bool "Support SUN disklabels" 161 default n 162 depends on FDISK && FEATURE_FDISK_WRITABLE 163 help 164 Enabling this option allows you to create or change SUN disklabels. 165 Most people can safely leave this option disabled. 166 167config FEATURE_OSF_LABEL 168 bool "Support BSD disklabels" 169 default n 170 depends on FDISK && FEATURE_FDISK_WRITABLE 171 help 172 Enabling this option allows you to create or change BSD disklabels 173 and define and edit BSD disk slices. 174 175config FEATURE_FDISK_ADVANCED 176 bool "Support expert mode" 177 default n 178 depends on FDISK && FEATURE_FDISK_WRITABLE 179 help 180 Enabling this option allows you to do terribly unsafe things like 181 define arbitrary drive geometry, move the beginning of data in a 182 partition, and similarly evil things. Unless you have a very good 183 reason you would be wise to leave this disabled. 184 185config FINDFS 186 bool "findfs" 187 default n 188 select VOLUMEID 189 help 190 Prints the name of a filesystem with given label or UUID. 191 WARNING: 192 With all submodules selected, it will add ~8k to busybox. 193 194config FREERAMDISK 195 bool "freeramdisk" 196 default n 197 help 198 Linux allows you to create ramdisks. This utility allows you to 199 delete them and completely free all memory that was used for the 200 ramdisk. For example, if you boot Linux into a ramdisk and later 201 pivot_root, you may want to free the memory that is allocated to the 202 ramdisk. If you have no use for freeing memory from a ramdisk, leave 203 this disabled. 204 205config FSCK_MINIX 206 bool "fsck_minix" 207 default n 208 help 209 The minix filesystem is a nice, small, compact, read-write filesystem 210 with little overhead. It is not a journaling filesystem however and 211 can experience corruption if it is not properly unmounted or if the 212 power goes off in the middle of a write. This utility allows you to 213 check for and attempt to repair any corruption that occurs to a minix 214 filesystem. 215 216config MKFS_MINIX 217 bool "mkfs_minix" 218 default n 219 help 220 The minix filesystem is a nice, small, compact, read-write filesystem 221 with little overhead. If you wish to be able to create minix 222 filesystems this utility will do the job for you. 223 224comment "Minix filesystem support" 225 depends on FSCK_MINIX || MKFS_MINIX 226 227config FEATURE_MINIX2 228 bool "Support Minix fs v2 (fsck_minix/mkfs_minix)" 229 default y 230 depends on FSCK_MINIX || MKFS_MINIX 231 help 232 If you wish to be able to create version 2 minix filesystems, enable 233 this. If you enabled 'mkfs_minix' then you almost certainly want to 234 be using the version 2 filesystem support. 235 236config MKFS_VFAT 237 bool "mkfs_vfat" 238 default n 239 help 240 Utility to create FAT32 filesystems. 241 242config GETOPT 243 bool "getopt" 244 default n 245 help 246 The getopt utility is used to break up (parse) options in command 247 lines to make it easy to write complex shell scripts that also check 248 for legal (and illegal) options. If you want to write horribly 249 complex shell scripts, or use some horribly complex shell script 250 written by others, this utility may be for you. Most people will 251 wisely leave this disabled. 252 253config HEXDUMP 254 bool "hexdump" 255 default n 256 help 257 The hexdump utility is used to display binary data in a readable 258 way that is comparable to the output from most hex editors. 259 260config FEATURE_HEXDUMP_REVERSE 261 bool "Support -R, reverse of 'hexdump -Cv'" 262 default n 263 depends on HEXDUMP 264 help 265 The hexdump utility is used to display binary data in an ascii 266 readable way. This option creates binary data from an ascii input. 267 NB: this option is non-standard. It's unwise to use it in scripts 268 aimed to be portable. 269 270config HD 271 bool "hd" 272 default n 273 select HEXDUMP 274 help 275 hd is an alias to hexdump -C. 276 277config HWCLOCK 278 bool "hwclock" 279 default n 280 help 281 The hwclock utility is used to read and set the hardware clock 282 on a system. This is primarily used to set the current time on 283 shutdown in the hardware clock, so the hardware will keep the 284 correct time when Linux is _not_ running. 285 286config FEATURE_HWCLOCK_LONG_OPTIONS 287 bool "Support long options (--hctosys,...)" 288 default n 289 depends on HWCLOCK && GETOPT_LONG 290 help 291 By default, the hwclock utility only uses short options. If you 292 are overly fond of its long options, such as --hctosys, --utc, etc) 293 then enable this option. 294 295config FEATURE_HWCLOCK_ADJTIME_FHS 296 bool "Use FHS /var/lib/hwclock/adjtime" 297 default y 298 depends on HWCLOCK 299 help 300 Starting with FHS 2.3, the adjtime state file is supposed to exist 301 at /var/lib/hwclock/adjtime instead of /etc/adjtime. If you wish 302 to use the FHS behavior, answer Y here, otherwise answer N for the 303 classic /etc/adjtime path. 304 305 pathname.com/fhs/pub/fhs-2.3.html#VARLIBHWCLOCKSTATEDIRECTORYFORHWCLO 306 307config IPCRM 308 bool "ipcrm" 309 default n 310 select FEATURE_SUID 311 help 312 The ipcrm utility allows the removal of System V interprocess 313 communication (IPC) objects and the associated data structures 314 from the system. 315 316config IPCS 317 bool "ipcs" 318 default n 319 select FEATURE_SUID 320 help 321 The ipcs utility is used to provide information on the currently 322 allocated System V interprocess (IPC) objects in the system. 323 324config LOSETUP 325 bool "losetup" 326 default n 327 help 328 losetup is used to associate or detach a loop device with a regular 329 file or block device, and to query the status of a loop device. This 330 version does not currently support enabling data encryption. 331 332config MDEV 333 bool "mdev" 334 default n 335 help 336 mdev is a mini-udev implementation for dynamically creating device 337 nodes in the /dev directory. 338 339 For more information, please see docs/mdev.txt 340 341config FEATURE_MDEV_CONF 342 bool "Support /etc/mdev.conf" 343 default n 344 depends on MDEV 345 help 346 Add support for the mdev config file to control ownership and 347 permissions of the device nodes. 348 349 For more information, please see docs/mdev.txt 350 351config FEATURE_MDEV_RENAME 352 bool "Support subdirs/symlinks" 353 default n 354 depends on FEATURE_MDEV_CONF 355 help 356 Add support for renaming devices and creating symlinks. 357 358 For more information, please see docs/mdev.txt 359 360config FEATURE_MDEV_RENAME_REGEXP 361 bool "Support regular expressions substitutions when renaming device" 362 default n 363 depends on FEATURE_MDEV_RENAME 364 help 365 Add support for regular expressions substitutions when renaming 366 device. 367 368config FEATURE_MDEV_EXEC 369 bool "Support command execution at device addition/removal" 370 default n 371 depends on FEATURE_MDEV_CONF 372 help 373 This adds support for an optional field to /etc/mdev.conf for 374 executing commands when devices are created/removed. 375 376 For more information, please see docs/mdev.txt 377 378config FEATURE_MDEV_LOAD_FIRMWARE 379 bool "Support loading of firmwares" 380 default n 381 depends on MDEV 382 help 383 Some devices need to load firmware before they can be usable. 384 385 These devices will request userspace look up the files in 386 /lib/firmware/ and if it exists, send it to the kernel for 387 loading into the hardware. 388 389config MKSWAP 390 bool "mkswap" 391 default n 392 help 393 The mkswap utility is used to configure a file or disk partition as 394 Linux swap space. This allows Linux to use the entire file or 395 partition as if it were additional RAM, which can greatly increase 396 the capability of low-memory machines. This additional memory is 397 much slower than real RAM, but can be very helpful at preventing your 398 applications being killed by the Linux out of memory (OOM) killer. 399 Once you have created swap space using 'mkswap' you need to enable 400 the swap space using the 'swapon' utility. 401 402config FEATURE_MKSWAP_V0 403 bool "Version 0 support" 404 default n 405 depends on MKSWAP 406# depends on MKSWAP && DEPRECATED 407 help 408 Enable support for the old v0 style. 409 If your kernel is older than 2.1.117, then v0 support is the 410 only option. 411 412config MORE 413 bool "more" 414 default n 415 help 416 more is a simple utility which allows you to read text one screen 417 sized page at a time. If you want to read text that is larger than 418 the screen, and you are using anything faster than a 300 baud modem, 419 you will probably find this utility very helpful. If you don't have 420 any need to reading text files, you can leave this disabled. 421 422config FEATURE_USE_TERMIOS 423 bool "Use termios to manipulate the screen" 424 default y 425 depends on MORE || TOP 426 help 427 This option allows utilities such as 'more' and 'top' to determine 428 the size of the screen. If you leave this disabled, your utilities 429 that display things on the screen will be especially primitive and 430 will be unable to determine the current screen size, and will be 431 unable to move the cursor. 432 433config VOLUMEID 434 bool #No description makes it a hidden option 435 default n 436 437config FEATURE_VOLUMEID_EXT 438 bool "Ext filesystem" 439 default n 440 depends on VOLUMEID 441 help 442 TODO 443 444config FEATURE_VOLUMEID_REISERFS 445 bool "Reiser filesystem" 446 default n 447 depends on VOLUMEID 448 help 449 TODO 450 451config FEATURE_VOLUMEID_FAT 452 bool "fat filesystem" 453 default n 454 depends on VOLUMEID 455 help 456 TODO 457 458config FEATURE_VOLUMEID_HFS 459 bool "hfs filesystem" 460 default n 461 depends on VOLUMEID 462 help 463 TODO 464 465config FEATURE_VOLUMEID_JFS 466 bool "jfs filesystem" 467 default n 468 depends on VOLUMEID 469 help 470 TODO 471 472### config FEATURE_VOLUMEID_UFS 473### bool "ufs filesystem" 474### default n 475### depends on VOLUMEID 476### help 477### TODO 478 479config FEATURE_VOLUMEID_XFS 480 bool "xfs filesystem" 481 default n 482 depends on VOLUMEID 483 help 484 TODO 485 486config FEATURE_VOLUMEID_NTFS 487 bool "ntfs filesystem" 488 default n 489 depends on VOLUMEID 490 help 491 TODO 492 493config FEATURE_VOLUMEID_ISO9660 494 bool "iso9660 filesystem" 495 default n 496 depends on VOLUMEID 497 help 498 TODO 499 500config FEATURE_VOLUMEID_UDF 501 bool "udf filesystem" 502 default n 503 depends on VOLUMEID 504 help 505 TODO 506 507config FEATURE_VOLUMEID_LUKS 508 bool "luks filesystem" 509 default n 510 depends on VOLUMEID 511 help 512 TODO 513 514config FEATURE_VOLUMEID_LINUXSWAP 515 bool "linux swap filesystem" 516 default n 517 depends on VOLUMEID 518 help 519 TODO 520 521### config FEATURE_VOLUMEID_LVM 522### bool "lvm" 523### default n 524### depends on VOLUMEID 525### help 526### TODO 527 528config FEATURE_VOLUMEID_CRAMFS 529 bool "cramfs filesystem" 530 default n 531 depends on VOLUMEID 532 help 533 TODO 534 535### config FEATURE_VOLUMEID_HPFS 536### bool "hpfs filesystem" 537### default n 538### depends on VOLUMEID 539### help 540### TODO 541 542config FEATURE_VOLUMEID_ROMFS 543 bool "romfs filesystem" 544 default n 545 depends on VOLUMEID 546 help 547 TODO 548 549config FEATURE_VOLUMEID_SYSV 550 bool "sysv filesystem" 551 default n 552 depends on VOLUMEID 553 help 554 TODO 555 556### config FEATURE_VOLUMEID_MINIX 557### bool "minix filesystem" 558### default n 559### depends on VOLUMEID 560### help 561### TODO 562 563### These only detect partition tables - not used (yet?) 564### config FEATURE_VOLUMEID_MAC 565### bool "mac filesystem" 566### default n 567### depends on VOLUMEID 568### help 569### TODO 570### 571### config FEATURE_VOLUMEID_MSDOS 572### bool "msdos filesystem" 573### default n 574### depends on VOLUMEID 575### help 576### TODO 577 578config FEATURE_VOLUMEID_OCFS2 579 bool "ocfs2 filesystem" 580 default n 581 depends on VOLUMEID 582 help 583 TODO 584 585### config FEATURE_VOLUMEID_HIGHPOINTRAID 586### bool "highpoint raid" 587### default n 588### depends on VOLUMEID 589### help 590### TODO 591 592### config FEATURE_VOLUMEID_ISWRAID 593### bool "intel raid" 594### default n 595### depends on VOLUMEID 596### help 597### TODO 598 599### config FEATURE_VOLUMEID_LSIRAID 600### bool "lsi raid" 601### default n 602### depends on VOLUMEID 603### help 604### TODO 605 606### config FEATURE_VOLUMEID_VIARAID 607### bool "via raid" 608### default n 609### depends on VOLUMEID 610### help 611### TODO 612 613### config FEATURE_VOLUMEID_SILICONRAID 614### bool "silicon raid" 615### default n 616### depends on VOLUMEID 617### help 618### TODO 619 620### config FEATURE_VOLUMEID_NVIDIARAID 621### bool "nvidia raid" 622### default n 623### depends on VOLUMEID 624### help 625### TODO 626 627### config FEATURE_VOLUMEID_PROMISERAID 628### bool "promise raid" 629### default n 630### depends on VOLUMEID 631### help 632### TODO 633 634config FEATURE_VOLUMEID_LINUXRAID 635 bool "linuxraid" 636 default n 637 depends on VOLUMEID 638 help 639 TODO 640 641config MOUNT 642 bool "mount" 643 default n 644 help 645 All files and filesystems in Unix are arranged into one big directory 646 tree. The 'mount' utility is used to graft a filesystem onto a 647 particular part of the tree. A filesystem can either live on a block 648 device, or it can be accessible over the network, as is the case with 649 NFS filesystems. Most people using BusyBox will also want to enable 650 the 'mount' utility. 651 652config FEATURE_MOUNT_FAKE 653 bool "Support option -f" 654 default n 655 depends on MOUNT 656 help 657 Enable support for faking a file system mount. 658 659config FEATURE_MOUNT_VERBOSE 660 bool "Support option -v" 661 default n 662 depends on MOUNT 663 help 664 Enable multi-level -v[vv...] verbose messages. Useful if you 665 debug mount problems and want to see what is exactly passed 666 to the kernel. 667 668config FEATURE_MOUNT_HELPERS 669 bool "Support mount helpers" 670 default n 671 depends on MOUNT 672 help 673 Enable mounting of virtual file systems via external helpers. 674 E.g. "mount obexfs#-b00.11.22.33.44.55 /mnt" will in effect call 675 "obexfs -b00.11.22.33.44.55 /mnt" 676 Also "mount -t sometype [-o opts] fs /mnt" will try 677 "sometype [-o opts] fs /mnt" if simple mount syscall fails. 678 The idea is to use such virtual filesystems in /etc/fstab. 679 680config FEATURE_MOUNT_LABEL 681 bool "Support specifiying devices by label or UUID" 682 default n 683 depends on MOUNT 684 select VOLUMEID 685 help 686 This allows for specifying a device by label or uuid, rather than by 687 name. This feature utilizes the same functionality as blkid/findfs. 688 689config FEATURE_MOUNT_NFS 690 bool "Support mounting NFS file systems" 691 default n 692 depends on MOUNT 693 select FEATURE_HAVE_RPC 694 select FEATURE_SYSLOG 695 help 696 Enable mounting of NFS file systems. 697 698config FEATURE_MOUNT_CIFS 699 bool "Support mounting CIFS/SMB file systems" 700 default n 701 depends on MOUNT 702 help 703 Enable support for samba mounts. 704 705config FEATURE_MOUNT_FLAGS 706 depends on MOUNT 707 bool "Support lots of -o flags in mount" 708 default y 709 help 710 Without this, mount only supports ro/rw/remount. With this, it 711 supports nosuid, suid, dev, nodev, exec, noexec, sync, async, atime, 712 noatime, diratime, nodiratime, loud, bind, move, shared, slave, 713 private, unbindable, rshared, rslave, rprivate, and runbindable. 714 715config FEATURE_MOUNT_FSTAB 716 depends on MOUNT 717 bool "Support /etc/fstab and -a" 718 default y 719 help 720 Support mount all and looking for files in /etc/fstab. 721 722config PIVOT_ROOT 723 bool "pivot_root" 724 default n 725 help 726 The pivot_root utility swaps the mount points for the root filesystem 727 with some other mounted filesystem. This allows you to do all sorts 728 of wild and crazy things with your Linux system and is far more 729 powerful than 'chroot'. 730 731 Note: This is for initrd in linux 2.4. Under initramfs (introduced 732 in linux 2.6) use switch_root instead. 733 734config RDATE 735 bool "rdate" 736 default n 737 help 738 The rdate utility allows you to synchronize the date and time of your 739 system clock with the date and time of a remote networked system using 740 the RFC868 protocol, which is built into the inetd daemon on most 741 systems. 742 743config RDEV 744 bool "rdev" 745 default n 746 help 747 Print the device node associated with the filesystem mounted at '/'. 748 749config READPROFILE 750 bool "readprofile" 751 default n 752 help 753 This allows you to parse /proc/profile for basic profiling. 754 755config RTCWAKE 756 bool "rtcwake" 757 default n 758 help 759 Enter a system sleep state until specified wakeup time. 760 761config SCRIPT 762 bool "script" 763 default n 764 help 765 The script makes typescript of terminal session. 766 767config SETARCH 768 bool "setarch" 769 default n 770 help 771 The linux32 utility is used to create a 32bit environment for the 772 specified program (usually a shell). It only makes sense to have 773 this util on a system that supports both 64bit and 32bit userland 774 (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...). 775 776config SWAPONOFF 777 bool "swaponoff" 778 default n 779 help 780 This option enables both the 'swapon' and the 'swapoff' utilities. 781 Once you have created some swap space using 'mkswap', you also need 782 to enable your swap space with the 'swapon' utility. The 'swapoff' 783 utility is used, typically at system shutdown, to disable any swap 784 space. If you are not using any swap space, you can leave this 785 option disabled. 786 787config FEATURE_SWAPON_PRI 788 bool "Support priority option -p" 789 default n 790 depends on SWAPONOFF 791 help 792 Enable support for setting swap device priority in swapon. 793 794config SWITCH_ROOT 795 bool "switch_root" 796 default n 797 help 798 The switch_root utility is used from initramfs to select a new 799 root device. Under initramfs, you have to use this instead of 800 pivot_root. (Stop reading here if you don't care why.) 801 802 Booting with initramfs extracts a gzipped cpio archive into rootfs 803 (which is a variant of ramfs/tmpfs). Because rootfs can't be moved 804 or unmounted*, pivot_root will not work from initramfs. Instead, 805 switch_root deletes everything out of rootfs (including itself), 806 does a mount --move that overmounts rootfs with the new root, and 807 then execs the specified init program. 808 809 * Because the Linux kernel uses rootfs internally as the starting 810 and ending point for searching through the kernel's doubly linked 811 list of active mount points. That's why. 812 813config UMOUNT 814 bool "umount" 815 default n 816 help 817 When you want to remove a mounted filesystem from its current mount 818 point, for example when you are shutting down the system, the 819 'umount' utility is the tool to use. If you enabled the 'mount' 820 utility, you almost certainly also want to enable 'umount'. 821 822config FEATURE_UMOUNT_ALL 823 bool "Support option -a" 824 default n 825 depends on UMOUNT 826 help 827 Support -a option to unmount all currently mounted filesystems. 828 829comment "Common options for mount/umount" 830 depends on MOUNT || UMOUNT 831 832config FEATURE_MOUNT_LOOP 833 bool "Support loopback mounts" 834 default n 835 depends on MOUNT || UMOUNT 836 help 837 Enabling this feature allows automatic mounting of files (containing 838 filesystem images) via the linux kernel's loopback devices. 839 The mount command will detect you are trying to mount a file instead 840 of a block device, and transparently associate the file with a 841 loopback device. The umount command will also free that loopback 842 device. 843 844 You can still use the 'losetup' utility (to manually associate files 845 with loop devices) if you need to do something advanced, such as 846 specify an offset or cryptographic options to the loopback device. 847 (If you don't want umount to free the loop device, use "umount -D".) 848 849config FEATURE_MTAB_SUPPORT 850 bool "Support for the old /etc/mtab file" 851 default n 852 depends on MOUNT || UMOUNT 853 select FEATURE_MOUNT_FAKE 854 help 855 Historically, Unix systems kept track of the currently mounted 856 partitions in the file "/etc/mtab". These days, the kernel exports 857 the list of currently mounted partitions in "/proc/mounts", rendering 858 the old mtab file obsolete. (In modern systems, /etc/mtab should be 859 a symlink to /proc/mounts.) 860 861 The only reason to have mount maintain an /etc/mtab file itself is if 862 your stripped-down embedded system does not have a /proc directory. 863 If you must use this, keep in mind it's inherently brittle (for 864 example a mount under chroot won't update it), can't handle modern 865 features like separate per-process filesystem namespaces, requires 866 that your /etc directory be writeable, tends to get easily confused 867 by --bind or --move mounts, won't update if you rename a directory 868 that contains a mount point, and so on. (In brief: avoid.) 869 870 About the only reason to use this is if you've removed /proc from 871 your kernel. 872 873endmenu 874