Documentation/translations/it_IT/process/magic-number.rst

   1 .. include:: ../disclaimer-ita.rst
   2
   3 :Original: :ref:`Documentation/process/magic-number.rst <magicnumbers>`
   4 :Translator: Federico Vaga <federico.vaga@vaga.pv.it>
   5
   6 .. _it_magicnumbers:
   7
   8 I numeri magici di Linux
   9 ========================
  10
  11 Questo documento è un registro dei numeri magici in uso.  Quando
  12 aggiungete un numero magico ad una struttura, dovreste aggiungerlo anche
  13 a questo documento; la cosa migliore è che tutti i numeri magici usati
  14 dalle varie strutture siano unici.
  15
  16 È **davvero** un'ottima idea proteggere le strutture dati del kernel con
  17 dei numeri magici.  Questo vi permette in fase d'esecuzione di (a) verificare
  18 se una struttura è stata malmenata, o (b) avete passato a una procedura la
  19 struttura errata.  Quest'ultimo è molto utile - particolarmente quando si passa
  20 una struttura dati tramite un puntatore void \*.  Il codice tty, per esempio,
  21 effettua questa operazione con regolarità passando avanti e indietro le
  22 strutture specifiche per driver e discipline.
  23
  24 Per utilizzare un numero magico, dovete dichiararlo all'inizio della struttura
  25 dati, come di seguito::
  26
  27         struct tty_ldisc {
  28                 int     magic;
  29                 ...
  30         };
  31
  32 Per favore, seguite questa direttiva quando aggiungerete migliorie al kernel!
  33 Mi ha risparmiato un numero illimitato di ore di debug, specialmente nei casi
  34 più ostici dove si è andati oltre la dimensione di un vettore e la struttura
  35 dati che lo seguiva in memoria è stata sovrascritta.  Seguendo questa
  36 direttiva, questi casi vengono identificati velocemente e in sicurezza.
  37
  38 Registro dei cambiamenti::
  39
  40                                         Theodore Ts'o
  41                                         31 Mar 94
  42
  43   La tabella magica è aggiornata a Linux 2.1.55.
  44
  45                                         Michael Chastain
  46                                         <mailto:mec@shout.net>
  47                                         22 Sep 1997
  48
  49   Ora dovrebbe essere aggiornata a Linux 2.1.112. Dato che
  50   siamo in un momento di congelamento delle funzionalità
  51   (*feature freeze*) è improbabile che qualcosa cambi prima
  52   della versione 2.2.x.  Le righe sono ordinate secondo il
  53   campo numero.
  54
  55                                         Krzysztof G. Baranowski
  56                                         <mailto: kgb@knm.org.pl>
  57                                         29 Jul 1998
  58
  59   Aggiornamento della tabella a Linux 2.5.45. Giusti nel congelamento
  60   delle funzionalità ma è comunque possibile che qualche nuovo
  61   numero magico s'intrufoli prima del kernel 2.6.x.
  62
  63                                         Petr Baudis
  64                                         <pasky@ucw.cz>
  65                                         03 Nov 2002
  66
  67   Aggiornamento della tabella magica a Linux 2.5.74.
  68
  69                                         Fabian Frederick
  70                                         <ffrederick@users.sourceforge.net>
  71                                         09 Jul 2003
  72
  73
  74 ===================== ================ ======================== ==========================================
  75 Nome magico           Numero           Struttura                File
  76 ===================== ================ ======================== ==========================================
  77 PG_MAGIC              'P'              pg_{read,write}_hdr      ``include/linux/pg.h``
  78 CMAGIC                0x0111           user                     ``include/linux/a.out.h``
  79 MKISS_DRIVER_MAGIC    0x04bf           mkiss_channel            ``drivers/net/mkiss.h``
  80 HDLC_MAGIC            0x239e           n_hdlc                   ``drivers/char/n_hdlc.c``
  81 APM_BIOS_MAGIC        0x4101           apm_user                 ``arch/x86/kernel/apm_32.c``
  82 CYCLADES_MAGIC        0x4359           cyclades_port            ``include/linux/cyclades.h``
  83 DB_MAGIC              0x4442           fc_info                  ``drivers/net/iph5526_novram.c``
  84 DL_MAGIC              0x444d           fc_info                  ``drivers/net/iph5526_novram.c``
  85 FASYNC_MAGIC          0x4601           fasync_struct            ``include/linux/fs.h``
  86 FF_MAGIC              0x4646           fc_info                  ``drivers/net/iph5526_novram.c``
  87 ISICOM_MAGIC          0x4d54           isi_port                 ``include/linux/isicom.h``
  88 PTY_MAGIC             0x5001                                    ``drivers/char/pty.c``
  89 PPP_MAGIC             0x5002           ppp                      ``include/linux/if_pppvar.h``
  90 SSTATE_MAGIC          0x5302           serial_state             ``include/linux/serial.h``
  91 SLIP_MAGIC            0x5302           slip                     ``drivers/net/slip.h``
  92 STRIP_MAGIC           0x5303           strip                    ``drivers/net/strip.c``
  93 SIXPACK_MAGIC         0x5304           sixpack                  ``drivers/net/hamradio/6pack.h``
  94 AX25_MAGIC            0x5316           ax_disp                  ``drivers/net/mkiss.h``
  95 TTY_MAGIC             0x5401           tty_struct               ``include/linux/tty.h``
  96 MGSL_MAGIC            0x5401           mgsl_info                ``drivers/char/synclink.c``
  97 TTY_DRIVER_MAGIC      0x5402           tty_driver               ``include/linux/tty_driver.h``
  98 MGSLPC_MAGIC          0x5402           mgslpc_info              ``drivers/char/pcmcia/synclink_cs.c``
  99 TTY_LDISC_MAGIC       0x5403           tty_ldisc                ``include/linux/tty_ldisc.h``
 100 USB_SERIAL_MAGIC      0x6702           usb_serial               ``drivers/usb/serial/usb-serial.h``
 101 FULL_DUPLEX_MAGIC     0x6969                                    ``drivers/net/ethernet/dec/tulip/de2104x.c``
 102 USB_BLUETOOTH_MAGIC   0x6d02           usb_bluetooth            ``drivers/usb/class/bluetty.c``
 103 RFCOMM_TTY_MAGIC      0x6d02                                    ``net/bluetooth/rfcomm/tty.c``
 104 USB_SERIAL_PORT_MAGIC 0x7301           usb_serial_port          ``drivers/usb/serial/usb-serial.h``
 105 CG_MAGIC              0x00090255       ufs_cylinder_group       ``include/linux/ufs_fs.h``
 106 RPORT_MAGIC           0x00525001       r_port                   ``drivers/char/rocket_int.h``
 107 LSEMAGIC              0x05091998       lse                      ``drivers/fc4/fc.c``
 108 GDTIOCTL_MAGIC        0x06030f07       gdth_iowr_str            ``drivers/scsi/gdth_ioctl.h``
 109 RIEBL_MAGIC           0x09051990                                ``drivers/net/atarilance.c``
 110 NBD_REQUEST_MAGIC     0x12560953       nbd_request              ``include/linux/nbd.h``
 111 RED_MAGIC2            0x170fc2a5       (any)                    ``mm/slab.c``
 112 BAYCOM_MAGIC          0x19730510       baycom_state             ``drivers/net/baycom_epp.c``
 113 ISDN_X25IFACE_MAGIC   0x1e75a2b9       isdn_x25iface_proto_data ``drivers/isdn/isdn_x25iface.h``
 114 ECP_MAGIC             0x21504345       cdkecpsig                ``include/linux/cdk.h``
 115 LSOMAGIC              0x27091997       lso                      ``drivers/fc4/fc.c``
 116 LSMAGIC               0x2a3b4d2a       ls                       ``drivers/fc4/fc.c``
 117 WANPIPE_MAGIC         0x414C4453       sdla_{dump,exec}         ``include/linux/wanpipe.h``
 118 CS_CARD_MAGIC         0x43525553       cs_card                  ``sound/oss/cs46xx.c``
 119 LABELCL_MAGIC         0x4857434c       labelcl_info_s           ``include/asm/ia64/sn/labelcl.h``
 120 ISDN_ASYNC_MAGIC      0x49344C01       modem_info               ``include/linux/isdn.h``
 121 CTC_ASYNC_MAGIC       0x49344C01       ctc_tty_info             ``drivers/s390/net/ctctty.c``
 122 ISDN_NET_MAGIC        0x49344C02       isdn_net_local_s         ``drivers/isdn/i4l/isdn_net_lib.h``
 123 SAVEKMSG_MAGIC2       0x4B4D5347       savekmsg                 ``arch/*/amiga/config.c``
 124 CS_STATE_MAGIC        0x4c4f4749       cs_state                 ``sound/oss/cs46xx.c``
 125 SLAB_C_MAGIC          0x4f17a36d       kmem_cache               ``mm/slab.c``
 126 COW_MAGIC             0x4f4f4f4d       cow_header_v1            ``arch/um/drivers/ubd_user.c``
 127 I810_CARD_MAGIC       0x5072696E       i810_card                ``sound/oss/i810_audio.c``
 128 TRIDENT_CARD_MAGIC    0x5072696E       trident_card             ``sound/oss/trident.c``
 129 ROUTER_MAGIC          0x524d4157       wan_device               [in ``wanrouter.h`` pre 3.9]
 130 SAVEKMSG_MAGIC1       0x53415645       savekmsg                 ``arch/*/amiga/config.c``
 131 GDA_MAGIC             0x58464552       gda                      ``arch/mips/include/asm/sn/gda.h``
 132 RED_MAGIC1            0x5a2cf071       (any)                    ``mm/slab.c``
 133 EEPROM_MAGIC_VALUE    0x5ab478d2       lanai_dev                ``drivers/atm/lanai.c``
 134 HDLCDRV_MAGIC         0x5ac6e778       hdlcdrv_state            ``include/linux/hdlcdrv.h``
 135 PCXX_MAGIC            0x5c6df104       channel                  ``drivers/char/pcxx.h``
 136 KV_MAGIC              0x5f4b565f       kernel_vars_s            ``arch/mips/include/asm/sn/klkernvars.h``
 137 I810_STATE_MAGIC      0x63657373       i810_state               ``sound/oss/i810_audio.c``
 138 TRIDENT_STATE_MAGIC   0x63657373       trient_state             ``sound/oss/trident.c``
 139 M3_CARD_MAGIC         0x646e6f50       m3_card                  ``sound/oss/maestro3.c``
 140 FW_HEADER_MAGIC       0x65726F66       fw_header                ``drivers/atm/fore200e.h``
 141 SLOT_MAGIC            0x67267321       slot                     ``drivers/hotplug/cpqphp.h``
 142 SLOT_MAGIC            0x67267322       slot                     ``drivers/hotplug/acpiphp.h``
 143 LO_MAGIC              0x68797548       nbd_device               ``include/linux/nbd.h``
 144 OPROFILE_MAGIC        0x6f70726f       super_block              ``drivers/oprofile/oprofilefs.h``
 145 M3_STATE_MAGIC        0x734d724d       m3_state                 ``sound/oss/maestro3.c``
 146 VMALLOC_MAGIC         0x87654320       snd_alloc_track          ``sound/core/memory.c``
 147 KMALLOC_MAGIC         0x87654321       snd_alloc_track          ``sound/core/memory.c``
 148 PWC_MAGIC             0x89DC10AB       pwc_device               ``drivers/usb/media/pwc.h``
 149 NBD_REPLY_MAGIC       0x96744668       nbd_reply                ``include/linux/nbd.h``
 150 ENI155_MAGIC          0xa54b872d       midway_eprom             ``drivers/atm/eni.h``
 151 CODA_MAGIC            0xC0DAC0DA       coda_file_info           ``fs/coda/coda_fs_i.h``
 152 DPMEM_MAGIC           0xc0ffee11       gdt_pci_sram             ``drivers/scsi/gdth.h``
 153 YAM_MAGIC             0xF10A7654       yam_port                 ``drivers/net/hamradio/yam.c``
 154 CCB_MAGIC             0xf2691ad2       ccb                      ``drivers/scsi/ncr53c8xx.c``
 155 QUEUE_MAGIC_FREE      0xf7e1c9a3       queue_entry              ``drivers/scsi/arm/queue.c``
 156 QUEUE_MAGIC_USED      0xf7e1cc33       queue_entry              ``drivers/scsi/arm/queue.c``
 157 HTB_CMAGIC            0xFEFAFEF1       htb_class                ``net/sched/sch_htb.c``
 158 NMI_MAGIC             0x48414d4d455201 nmi_s                    ``arch/mips/include/asm/sn/nmi.h``
 159 ===================== ================ ======================== ==========================================
 160
 161 Da notare che ci sono anche dei numeri magici specifici per driver nel
 162 *sound memory management*. Consultate ``include/sound/sndmagic.h`` per una
 163 lista completa.  Molti driver audio OSS hanno i loro numeri magici costruiti a
 164 partire dall'identificativo PCI della scheda audio - nemmeno questi sono
 165 elencati in questo file.
 166
 167 Il file-system HFS è un altro grande utilizzatore di numeri magici - potete
 168 trovarli qui ``fs/hfs/hfs.h``.