| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 1 | This file is a registry of magic numbers which are in use. When you |
| 2 | add a magic number to a structure, you should also add it to this |
| 3 | file, since it is best if the magic numbers used by various structures |
| 4 | are unique. |
| 5 | |
| 6 | It is a *very* good idea to protect kernel data structures with magic |
| 7 | numbers. This allows you to check at run time whether (a) a structure |
| 8 | has been clobbered, or (b) you've passed the wrong structure to a |
| 9 | routine. This last is especially useful --- particularly when you are |
| 10 | passing pointers to structures via a void * pointer. The tty code, |
| 11 | for example, does this frequently to pass driver-specific and line |
| 12 | discipline-specific structures back and forth. |
| 13 | |
| 14 | The way to use magic numbers is to declare then at the beginning of |
| 15 | the structure, like so: |
| 16 | |
| 17 | struct tty_ldisc { |
| 18 | int magic; |
| 19 | ... |
| 20 | }; |
| 21 | |
| 22 | Please follow this discipline when you are adding future enhancements |
| 23 | to the kernel! It has saved me countless hours of debugging, |
| 24 | especially in the screwy cases where an array has been overrun and |
| 25 | structures following the array have been overwritten. Using this |
| 26 | discipline, these cases get detected quickly and safely. |
| 27 | |
| 28 | Theodore Ts'o |
| 29 | 31 Mar 94 |
| 30 | |
| 31 | The magic table is current to Linux 2.1.55. |
| 32 | |
| 33 | Michael Chastain |
| 34 | <mailto:mec@shout.net> |
| 35 | 22 Sep 1997 |
| 36 | |
| 37 | Now it should be up to date with Linux 2.1.112. Because |
| 38 | we are in feature freeze time it is very unlikely that |
| 39 | something will change before 2.2.x. The entries are |
| 40 | sorted by number field. |
| 41 | |
| 42 | Krzysztof G. Baranowski |
| 43 | <mailto: kgb@knm.org.pl> |
| 44 | 29 Jul 1998 |
| 45 | |
| 46 | Updated the magic table to Linux 2.5.45. Right over the feature freeze, |
| 47 | but it is possible that some new magic numbers will sneak into the |
| 48 | kernel before 2.6.x yet. |
| 49 | |
| 50 | Petr Baudis |
| 51 | <pasky@ucw.cz> |
| 52 | 03 Nov 2002 |
| 53 | |
| 54 | Updated the magic table to Linux 2.5.74. |
| 55 | |
| 56 | Fabian Frederick |
| 57 | <ffrederick@users.sourceforge.net> |
| 58 | 09 Jul 2003 |
| 59 | |
| 60 | |
| 61 | Magic Name Number Structure File |
| 62 | =========================================================================== |
| 63 | PG_MAGIC 'P' pg_{read,write}_hdr include/linux/pg.h |
| 64 | CMAGIC 0x0111 user include/linux/a.out.h |
| 65 | MKISS_DRIVER_MAGIC 0x04bf mkiss_channel drivers/net/mkiss.h |
| 66 | HDLC_MAGIC 0x239e n_hdlc drivers/char/n_hdlc.c |
| 67 | APM_BIOS_MAGIC 0x4101 apm_user arch/x86/kernel/apm_32.c |
| 68 | CYCLADES_MAGIC 0x4359 cyclades_port include/linux/cyclades.h |
| 69 | DB_MAGIC 0x4442 fc_info drivers/net/iph5526_novram.c |
| 70 | DL_MAGIC 0x444d fc_info drivers/net/iph5526_novram.c |
| 71 | FASYNC_MAGIC 0x4601 fasync_struct include/linux/fs.h |
| 72 | FF_MAGIC 0x4646 fc_info drivers/net/iph5526_novram.c |
| 73 | ISICOM_MAGIC 0x4d54 isi_port include/linux/isicom.h |
| 74 | PTY_MAGIC 0x5001 drivers/char/pty.c |
| 75 | PPP_MAGIC 0x5002 ppp include/linux/if_pppvar.h |
| 76 | SERIAL_MAGIC 0x5301 async_struct include/linux/serial.h |
| 77 | SSTATE_MAGIC 0x5302 serial_state include/linux/serial.h |
| 78 | SLIP_MAGIC 0x5302 slip drivers/net/slip.h |
| 79 | STRIP_MAGIC 0x5303 strip drivers/net/strip.c |
| 80 | X25_ASY_MAGIC 0x5303 x25_asy drivers/net/x25_asy.h |
| 81 | SIXPACK_MAGIC 0x5304 sixpack drivers/net/hamradio/6pack.h |
| 82 | AX25_MAGIC 0x5316 ax_disp drivers/net/mkiss.h |
| 83 | TTY_MAGIC 0x5401 tty_struct include/linux/tty.h |
| 84 | MGSL_MAGIC 0x5401 mgsl_info drivers/char/synclink.c |
| 85 | TTY_DRIVER_MAGIC 0x5402 tty_driver include/linux/tty_driver.h |
| 86 | MGSLPC_MAGIC 0x5402 mgslpc_info drivers/char/pcmcia/synclink_cs.c |
| 87 | TTY_LDISC_MAGIC 0x5403 tty_ldisc include/linux/tty_ldisc.h |
| 88 | USB_SERIAL_MAGIC 0x6702 usb_serial drivers/usb/serial/usb-serial.h |
| 89 | FULL_DUPLEX_MAGIC 0x6969 drivers/net/ethernet/dec/tulip/de2104x.c |
| 90 | USB_BLUETOOTH_MAGIC 0x6d02 usb_bluetooth drivers/usb/class/bluetty.c |
| 91 | RFCOMM_TTY_MAGIC 0x6d02 net/bluetooth/rfcomm/tty.c |
| 92 | USB_SERIAL_PORT_MAGIC 0x7301 usb_serial_port drivers/usb/serial/usb-serial.h |
| 93 | CG_MAGIC 0x00090255 ufs_cylinder_group include/linux/ufs_fs.h |
| 94 | RPORT_MAGIC 0x00525001 r_port drivers/char/rocket_int.h |
| 95 | LSEMAGIC 0x05091998 lse drivers/fc4/fc.c |
| 96 | GDTIOCTL_MAGIC 0x06030f07 gdth_iowr_str drivers/scsi/gdth_ioctl.h |
| 97 | RIEBL_MAGIC 0x09051990 drivers/net/atarilance.c |
| 98 | NBD_REQUEST_MAGIC 0x12560953 nbd_request include/linux/nbd.h |
| 99 | RED_MAGIC2 0x170fc2a5 (any) mm/slab.c |
| 100 | BAYCOM_MAGIC 0x19730510 baycom_state drivers/net/baycom_epp.c |
| 101 | ISDN_X25IFACE_MAGIC 0x1e75a2b9 isdn_x25iface_proto_data |
| 102 | drivers/isdn/isdn_x25iface.h |
| 103 | ECP_MAGIC 0x21504345 cdkecpsig include/linux/cdk.h |
| 104 | LSOMAGIC 0x27091997 lso drivers/fc4/fc.c |
| 105 | LSMAGIC 0x2a3b4d2a ls drivers/fc4/fc.c |
| 106 | WANPIPE_MAGIC 0x414C4453 sdla_{dump,exec} include/linux/wanpipe.h |
| 107 | CS_CARD_MAGIC 0x43525553 cs_card sound/oss/cs46xx.c |
| 108 | LABELCL_MAGIC 0x4857434c labelcl_info_s include/asm/ia64/sn/labelcl.h |
| 109 | ISDN_ASYNC_MAGIC 0x49344C01 modem_info include/linux/isdn.h |
| 110 | CTC_ASYNC_MAGIC 0x49344C01 ctc_tty_info drivers/s390/net/ctctty.c |
| 111 | ISDN_NET_MAGIC 0x49344C02 isdn_net_local_s drivers/isdn/i4l/isdn_net_lib.h |
| 112 | SAVEKMSG_MAGIC2 0x4B4D5347 savekmsg arch/*/amiga/config.c |
| 113 | CS_STATE_MAGIC 0x4c4f4749 cs_state sound/oss/cs46xx.c |
| 114 | SLAB_C_MAGIC 0x4f17a36d kmem_cache mm/slab.c |
| 115 | COW_MAGIC 0x4f4f4f4d cow_header_v1 arch/um/drivers/ubd_user.c |
| 116 | I810_CARD_MAGIC 0x5072696E i810_card sound/oss/i810_audio.c |
| 117 | TRIDENT_CARD_MAGIC 0x5072696E trident_card sound/oss/trident.c |
| 118 | ROUTER_MAGIC 0x524d4157 wan_device [in wanrouter.h pre 3.9] |
| 119 | SAVEKMSG_MAGIC1 0x53415645 savekmsg arch/*/amiga/config.c |
| 120 | GDA_MAGIC 0x58464552 gda arch/mips/include/asm/sn/gda.h |
| 121 | RED_MAGIC1 0x5a2cf071 (any) mm/slab.c |
| 122 | EEPROM_MAGIC_VALUE 0x5ab478d2 lanai_dev drivers/atm/lanai.c |
| 123 | HDLCDRV_MAGIC 0x5ac6e778 hdlcdrv_state include/linux/hdlcdrv.h |
| 124 | PCXX_MAGIC 0x5c6df104 channel drivers/char/pcxx.h |
| 125 | KV_MAGIC 0x5f4b565f kernel_vars_s arch/mips/include/asm/sn/klkernvars.h |
| 126 | I810_STATE_MAGIC 0x63657373 i810_state sound/oss/i810_audio.c |
| 127 | TRIDENT_STATE_MAGIC 0x63657373 trient_state sound/oss/trident.c |
| 128 | M3_CARD_MAGIC 0x646e6f50 m3_card sound/oss/maestro3.c |
| 129 | FW_HEADER_MAGIC 0x65726F66 fw_header drivers/atm/fore200e.h |
| 130 | SLOT_MAGIC 0x67267321 slot drivers/hotplug/cpqphp.h |
| 131 | SLOT_MAGIC 0x67267322 slot drivers/hotplug/acpiphp.h |
| 132 | LO_MAGIC 0x68797548 nbd_device include/linux/nbd.h |
| 133 | OPROFILE_MAGIC 0x6f70726f super_block drivers/oprofile/oprofilefs.h |
| 134 | M3_STATE_MAGIC 0x734d724d m3_state sound/oss/maestro3.c |
| 135 | VMALLOC_MAGIC 0x87654320 snd_alloc_track sound/core/memory.c |
| 136 | KMALLOC_MAGIC 0x87654321 snd_alloc_track sound/core/memory.c |
| 137 | PWC_MAGIC 0x89DC10AB pwc_device drivers/usb/media/pwc.h |
| 138 | NBD_REPLY_MAGIC 0x96744668 nbd_reply include/linux/nbd.h |
| 139 | ENI155_MAGIC 0xa54b872d midway_eprom drivers/atm/eni.h |
| 140 | CODA_MAGIC 0xC0DAC0DA coda_file_info fs/coda/coda_fs_i.h |
| 141 | DPMEM_MAGIC 0xc0ffee11 gdt_pci_sram drivers/scsi/gdth.h |
| 142 | YAM_MAGIC 0xF10A7654 yam_port drivers/net/hamradio/yam.c |
| 143 | CCB_MAGIC 0xf2691ad2 ccb drivers/scsi/ncr53c8xx.c |
| 144 | QUEUE_MAGIC_FREE 0xf7e1c9a3 queue_entry drivers/scsi/arm/queue.c |
| 145 | QUEUE_MAGIC_USED 0xf7e1cc33 queue_entry drivers/scsi/arm/queue.c |
| 146 | HTB_CMAGIC 0xFEFAFEF1 htb_class net/sched/sch_htb.c |
| 147 | NMI_MAGIC 0x48414d4d455201 nmi_s arch/mips/include/asm/sn/nmi.h |
| 148 | |
| 149 | Note that there are also defined special per-driver magic numbers in sound |
| 150 | memory management. See include/sound/sndmagic.h for complete list of them. Many |
| 151 | OSS sound drivers have their magic numbers constructed from the soundcard PCI |
| 152 | ID - these are not listed here as well. |
| 153 | |
| 154 | IrDA subsystem also uses large number of own magic numbers, see |
| 155 | include/net/irda/irda.h for a complete list of them. |
| 156 | |
| 157 | HFS is another larger user of magic numbers - you can find them in |
| 158 | fs/hfs/hfs.h. |