8a8dabf2dd
Historically the N_TTY driver could never fail but this has become broken over time. Rather than trying to rewrite half the ldisc layer to fix the breakage introduce a second level of fallback with an N_NULL ldisc which cannot fail, and thus restore the guarantees required by the ldisc layer. We still try and fail to N_TTY first. It's much more useful to find yourself back in your old ldisc (first attempt) or in N_TTY (second attempt), and while I'm not aware of any code out there that makes those assumptions it's good to drive(r) defensively. Signed-off-by: Alan Cox <alan@linux.intel.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
41 lines
1.5 KiB
C
41 lines
1.5 KiB
C
#ifndef _UAPI_LINUX_TTY_H
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#define _UAPI_LINUX_TTY_H
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/*
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* 'tty.h' defines some structures used by tty_io.c and some defines.
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*/
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#define NR_LDISCS 30
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/* line disciplines */
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#define N_TTY 0
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#define N_SLIP 1
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#define N_MOUSE 2
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#define N_PPP 3
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#define N_STRIP 4
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#define N_AX25 5
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#define N_X25 6 /* X.25 async */
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#define N_6PACK 7
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#define N_MASC 8 /* Reserved for Mobitex module <kaz@cafe.net> */
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#define N_R3964 9 /* Reserved for Simatic R3964 module */
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#define N_PROFIBUS_FDL 10 /* Reserved for Profibus */
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#define N_IRDA 11 /* Linux IrDa - http://irda.sourceforge.net/ */
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#define N_SMSBLOCK 12 /* SMS block mode - for talking to GSM data */
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/* cards about SMS messages */
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#define N_HDLC 13 /* synchronous HDLC */
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#define N_SYNC_PPP 14 /* synchronous PPP */
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#define N_HCI 15 /* Bluetooth HCI UART */
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#define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */
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#define N_SLCAN 17 /* Serial / USB serial CAN Adaptors */
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#define N_PPS 18 /* Pulse per Second */
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#define N_V253 19 /* Codec control over voice modem */
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#define N_CAIF 20 /* CAIF protocol for talking to modems */
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#define N_GSM0710 21 /* GSM 0710 Mux */
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#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */
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#define N_TRACESINK 23 /* Trace data routing for MIPI P1149.7 */
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#define N_TRACEROUTER 24 /* Trace data routing for MIPI P1149.7 */
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#define N_NCI 25 /* NFC NCI UART */
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#define N_SPEAKUP 26 /* Speakup communication with synths */
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#define N_NULL 27 /* Null ldisc used for error handling */
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#endif /* _UAPI_LINUX_TTY_H */
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