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Diffstat (limited to 'Documentation/magic-number.txt')
| -rw-r--r-- | Documentation/magic-number.txt | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/Documentation/magic-number.txt b/Documentation/magic-number.txt new file mode 100644 index 000000000..4c8e142db --- /dev/null +++ b/Documentation/magic-number.txt @@ -0,0 +1,160 @@ +This file is a registry of magic numbers which are in use. When you +add a magic number to a structure, you should also add it to this +file, since it is best if the magic numbers used by various structures +are unique. + +It is a *very* good idea to protect kernel data structures with magic +numbers. This allows you to check at run time whether (a) a structure +has been clobbered, or (b) you've passed the wrong structure to a +routine. This last is especially useful --- particularly when you are +passing pointers to structures via a void * pointer. The tty code, +for example, does this frequently to pass driver-specific and line +discipline-specific structures back and forth. + +The way to use magic numbers is to declare then at the beginning of +the structure, like so: + +struct tty_ldisc { + int magic; + ... +}; + +Please follow this discipline when you are adding future enhancements +to the kernel! It has saved me countless hours of debugging, +especially in the screwy cases where an array has been overrun and +structures following the array have been overwritten. Using this +discipline, these cases get detected quickly and safely. + + Theodore Ts'o + 31 Mar 94 + +The magic table is current to Linux 2.1.55. + + Michael Chastain + <mailto:mec@shout.net> + 22 Sep 1997 + +Now it should be up to date with Linux 2.1.112. Because +we are in feature freeze time it is very unlikely that +something will change before 2.2.x. The entries are +sorted by number field. + + Krzysztof G. Baranowski + <mailto: kgb@knm.org.pl> + 29 Jul 1998 + +Updated the magic table to Linux 2.5.45. Right over the feature freeze, +but it is possible that some new magic numbers will sneak into the +kernel before 2.6.x yet. + + Petr Baudis + <pasky@ucw.cz> + 03 Nov 2002 + +Updated the magic table to Linux 2.5.74. + + Fabian Frederick + <ffrederick@users.sourceforge.net> + 09 Jul 2003 + + +Magic Name Number Structure File +=========================================================================== +PG_MAGIC 'P' pg_{read,write}_hdr include/linux/pg.h +CMAGIC 0x0111 user include/linux/a.out.h +MKISS_DRIVER_MAGIC 0x04bf mkiss_channel drivers/net/mkiss.h +HDLC_MAGIC 0x239e n_hdlc drivers/char/n_hdlc.c +APM_BIOS_MAGIC 0x4101 apm_user arch/x86/kernel/apm_32.c +CYCLADES_MAGIC 0x4359 cyclades_port include/linux/cyclades.h +DB_MAGIC 0x4442 fc_info drivers/net/iph5526_novram.c +DL_MAGIC 0x444d fc_info drivers/net/iph5526_novram.c +FASYNC_MAGIC 0x4601 fasync_struct include/linux/fs.h +FF_MAGIC 0x4646 fc_info drivers/net/iph5526_novram.c +ISICOM_MAGIC 0x4d54 isi_port include/linux/isicom.h +PTY_MAGIC 0x5001 drivers/char/pty.c +PPP_MAGIC 0x5002 ppp include/linux/if_pppvar.h +SERIAL_MAGIC 0x5301 async_struct include/linux/serial.h +SSTATE_MAGIC 0x5302 serial_state include/linux/serial.h +SLIP_MAGIC 0x5302 slip drivers/net/slip.h +STRIP_MAGIC 0x5303 strip drivers/net/strip.c +X25_ASY_MAGIC 0x5303 x25_asy drivers/net/x25_asy.h +SIXPACK_MAGIC 0x5304 sixpack drivers/net/hamradio/6pack.h +AX25_MAGIC 0x5316 ax_disp drivers/net/mkiss.h +TTY_MAGIC 0x5401 tty_struct include/linux/tty.h +MGSL_MAGIC 0x5401 mgsl_info drivers/char/synclink.c +TTY_DRIVER_MAGIC 0x5402 tty_driver include/linux/tty_driver.h +MGSLPC_MAGIC 0x5402 mgslpc_info drivers/char/pcmcia/synclink_cs.c +TTY_LDISC_MAGIC 0x5403 tty_ldisc include/linux/tty_ldisc.h +USB_SERIAL_MAGIC 0x6702 usb_serial drivers/usb/serial/usb-serial.h +FULL_DUPLEX_MAGIC 0x6969 drivers/net/ethernet/dec/tulip/de2104x.c +USB_BLUETOOTH_MAGIC 0x6d02 usb_bluetooth drivers/usb/class/bluetty.c +RFCOMM_TTY_MAGIC 0x6d02 net/bluetooth/rfcomm/tty.c +USB_SERIAL_PORT_MAGIC 0x7301 usb_serial_port drivers/usb/serial/usb-serial.h +CG_MAGIC 0x00090255 ufs_cylinder_group include/linux/ufs_fs.h +RPORT_MAGIC 0x00525001 r_port drivers/char/rocket_int.h +LSEMAGIC 0x05091998 lse drivers/fc4/fc.c +GDTIOCTL_MAGIC 0x06030f07 gdth_iowr_str drivers/scsi/gdth_ioctl.h +RIEBL_MAGIC 0x09051990 drivers/net/atarilance.c +NBD_REQUEST_MAGIC 0x12560953 nbd_request include/linux/nbd.h +RED_MAGIC2 0x170fc2a5 (any) mm/slab.c +BAYCOM_MAGIC 0x19730510 baycom_state drivers/net/baycom_epp.c +ISDN_X25IFACE_MAGIC 0x1e75a2b9 isdn_x25iface_proto_data + drivers/isdn/isdn_x25iface.h +ECP_MAGIC 0x21504345 cdkecpsig include/linux/cdk.h +LSOMAGIC 0x27091997 lso drivers/fc4/fc.c +LSMAGIC 0x2a3b4d2a ls drivers/fc4/fc.c +WANPIPE_MAGIC 0x414C4453 sdla_{dump,exec} include/linux/wanpipe.h +CS_CARD_MAGIC 0x43525553 cs_card sound/oss/cs46xx.c +LABELCL_MAGIC 0x4857434c labelcl_info_s include/asm/ia64/sn/labelcl.h +ISDN_ASYNC_MAGIC 0x49344C01 modem_info include/linux/isdn.h +CTC_ASYNC_MAGIC 0x49344C01 ctc_tty_info drivers/s390/net/ctctty.c +ISDN_NET_MAGIC 0x49344C02 isdn_net_local_s drivers/isdn/i4l/isdn_net_lib.h +SAVEKMSG_MAGIC2 0x4B4D5347 savekmsg arch/*/amiga/config.c +CS_STATE_MAGIC 0x4c4f4749 cs_state sound/oss/cs46xx.c +SLAB_C_MAGIC 0x4f17a36d kmem_cache mm/slab.c +COW_MAGIC 0x4f4f4f4d cow_header_v1 arch/um/drivers/ubd_user.c +I810_CARD_MAGIC 0x5072696E i810_card sound/oss/i810_audio.c +TRIDENT_CARD_MAGIC 0x5072696E trident_card sound/oss/trident.c +ROUTER_MAGIC 0x524d4157 wan_device [in wanrouter.h pre 3.9] +SCC_MAGIC 0x52696368 gs_port drivers/char/scc.h +SAVEKMSG_MAGIC1 0x53415645 savekmsg arch/*/amiga/config.c +GDA_MAGIC 0x58464552 gda arch/mips/include/asm/sn/gda.h +RED_MAGIC1 0x5a2cf071 (any) mm/slab.c +EEPROM_MAGIC_VALUE 0x5ab478d2 lanai_dev drivers/atm/lanai.c +HDLCDRV_MAGIC 0x5ac6e778 hdlcdrv_state include/linux/hdlcdrv.h +PCXX_MAGIC 0x5c6df104 channel drivers/char/pcxx.h +KV_MAGIC 0x5f4b565f kernel_vars_s arch/mips/include/asm/sn/klkernvars.h +I810_STATE_MAGIC 0x63657373 i810_state sound/oss/i810_audio.c +TRIDENT_STATE_MAGIC 0x63657373 trient_state sound/oss/trident.c +M3_CARD_MAGIC 0x646e6f50 m3_card sound/oss/maestro3.c +FW_HEADER_MAGIC 0x65726F66 fw_header drivers/atm/fore200e.h +SLOT_MAGIC 0x67267321 slot drivers/hotplug/cpqphp.h +SLOT_MAGIC 0x67267322 slot drivers/hotplug/acpiphp.h +LO_MAGIC 0x68797548 nbd_device include/linux/nbd.h +OPROFILE_MAGIC 0x6f70726f super_block drivers/oprofile/oprofilefs.h +M3_STATE_MAGIC 0x734d724d m3_state sound/oss/maestro3.c +VMALLOC_MAGIC 0x87654320 snd_alloc_track sound/core/memory.c +KMALLOC_MAGIC 0x87654321 snd_alloc_track sound/core/memory.c +PWC_MAGIC 0x89DC10AB pwc_device drivers/usb/media/pwc.h +NBD_REPLY_MAGIC 0x96744668 nbd_reply include/linux/nbd.h +ENI155_MAGIC 0xa54b872d midway_eprom drivers/atm/eni.h +SCI_MAGIC 0xbabeface gs_port drivers/char/sh-sci.h +CODA_MAGIC 0xC0DAC0DA coda_file_info fs/coda/coda_fs_i.h +DPMEM_MAGIC 0xc0ffee11 gdt_pci_sram drivers/scsi/gdth.h +YAM_MAGIC 0xF10A7654 yam_port drivers/net/hamradio/yam.c +CCB_MAGIC 0xf2691ad2 ccb drivers/scsi/ncr53c8xx.c +QUEUE_MAGIC_FREE 0xf7e1c9a3 queue_entry drivers/scsi/arm/queue.c +QUEUE_MAGIC_USED 0xf7e1cc33 queue_entry drivers/scsi/arm/queue.c +HTB_CMAGIC 0xFEFAFEF1 htb_class net/sched/sch_htb.c +NMI_MAGIC 0x48414d4d455201 nmi_s arch/mips/include/asm/sn/nmi.h + +Note that there are also defined special per-driver magic numbers in sound +memory management. See include/sound/sndmagic.h for complete list of them. Many +OSS sound drivers have their magic numbers constructed from the soundcard PCI +ID - these are not listed here as well. + +IrDA subsystem also uses large number of own magic numbers, see +include/net/irda/irda.h for a complete list of them. + +HFS is another larger user of magic numbers - you can find them in +fs/hfs/hfs.h. |