arch/um/Kconfig_char

   1
   2 menu "Character Devices"
   3
   4 config STDERR_CONSOLE
   5         bool "stderr console"
   6         default y
   7         help
   8         console driver which dumps all printk messages to stderr.
   9
  10 config STDIO_CONSOLE
  11         bool
  12         default y
  13
  14 config SSL
  15         bool "Virtual serial line"
  16         help
  17         The User-Mode Linux environment allows you to create virtual serial
  18         lines on the UML that are usually made to show up on the host as
  19         ttys or ptys.
  20
  21         See <http://user-mode-linux.sourceforge.net/input.html> for more
  22         information and command line examples of how to use this facility.
  23
  24         Unless you have a specific reason for disabling this, say Y.
  25
  26 config NULL_CHAN
  27         bool "null channel support"
  28         help
  29         This option enables support for attaching UML consoles and serial
  30         lines to a device similar to /dev/null.  Data written to it disappears
  31         and there is never any data to be read.
  32
  33 config PORT_CHAN
  34         bool "port channel support"
  35         help
  36         This option enables support for attaching UML consoles and serial
  37         lines to host portals.  They may be accessed with 'telnet <host>
  38         <port number>'.  Any number of consoles and serial lines may be
  39         attached to a single portal, although what UML device you get when
  40         you telnet to that portal will be unpredictable.
  41         It is safe to say 'Y' here.
  42
  43 config PTY_CHAN
  44         bool "pty channel support"
  45         help
  46         This option enables support for attaching UML consoles and serial
  47         lines to host pseudo-terminals.  Access to both traditional
  48         pseudo-terminals (/dev/pty*) and pts pseudo-terminals are controlled
  49         with this option.  The assignment of UML devices to host devices
  50         will be announced in the kernel message log.
  51         It is safe to say 'Y' here.
  52
  53 config TTY_CHAN
  54         bool "tty channel support"
  55         help
  56         This option enables support for attaching UML consoles and serial
  57         lines to host terminals.  Access to both virtual consoles
  58         (/dev/tty*) and the slave side of pseudo-terminals (/dev/ttyp* and
  59         /dev/pts/*) are controlled by this option.
  60         It is safe to say 'Y' here.
  61
  62 config XTERM_CHAN
  63         bool "xterm channel support"
  64         help
  65         This option enables support for attaching UML consoles and serial
  66         lines to xterms.  Each UML device so assigned will be brought up in
  67         its own xterm.
  68         If you disable this option, then CONFIG_PT_PROXY will be disabled as
  69         well, since UML's gdb currently requires an xterm.
  70         It is safe to say 'Y' here.
  71
  72 config NOCONFIG_CHAN
  73         bool
  74         default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
  75
  76 config CON_ZERO_CHAN
  77         string "Default main console channel initialization"
  78         default "fd:0,fd:1"
  79         help
  80         This is the string describing the channel to which the main console
  81         will be attached by default.  This value can be overridden from the
  82         command line.  The default value is "fd:0,fd:1", which attaches the
  83         main console to stdin and stdout.
  84         It is safe to leave this unchanged.
  85
  86 config CON_CHAN
  87         string "Default console channel initialization"
  88         default "xterm"
  89         help
  90         This is the string describing the channel to which all consoles
  91         except the main console will be attached by default.  This value can
  92         be overridden from the command line.  The default value is "xterm",
  93         which brings them up in xterms.
  94         It is safe to leave this unchanged, although you may wish to change
  95         this if you expect the UML that you build to be run in environments
  96         which don't have X or xterm available.
  97
  98 config SSL_CHAN
  99         string "Default serial line channel initialization"
 100         default "pty"
 101         help
 102         This is the string describing the channel to which the serial lines
 103         will be attached by default.  This value can be overridden from the
 104         command line.  The default value is "pty", which attaches them to
 105         traditional pseudo-terminals.
 106         It is safe to leave this unchanged, although you may wish to change
 107         this if you expect the UML that you build to be run in environments
 108         which don't have a set of /dev/pty* devices.
 109
 110 config UNIX98_PTYS
 111         bool "Unix98 PTY support"
 112         ---help---
 113           A pseudo terminal (PTY) is a software device consisting of two
 114           halves: a master and a slave. The slave device behaves identical to
 115           a physical terminal; the master device is used by a process to
 116           read data from and write data to the slave, thereby emulating a
 117           terminal. Typical programs for the master side are telnet servers
 118           and xterms.
 119
 120           Linux has traditionally used the BSD-like names /dev/ptyxx for
 121           masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
 122           has a number of problems. The GNU C library glibc 2.1 and later,
 123           however, supports the Unix98 naming standard: in order to acquire a
 124           pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
 125           terminal is then made available to the process and the pseudo
 126           terminal slave can be accessed as /dev/pts/<number>. What was
 127           traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
 128
 129           All modern Linux systems use the Unix98 ptys.  Say Y unless
 130           you're on an embedded system and want to conserve memory.
 131
 132 config LEGACY_PTYS
 133         bool "Legacy (BSD) PTY support"
 134         default y
 135         ---help---
 136           A pseudo terminal (PTY) is a software device consisting of two
 137           halves: a master and a slave. The slave device behaves identical to
 138           a physical terminal; the master device is used by a process to
 139           read data from and write data to the slave, thereby emulating a
 140           terminal. Typical programs for the master side are telnet servers
 141           and xterms.
 142
 143           Linux has traditionally used the BSD-like names /dev/ptyxx
 144           for masters and /dev/ttyxx for slaves of pseudo
 145           terminals. This scheme has a number of problems, including
 146           security.  This option enables these legacy devices; on most
 147           systems, it is safe to say N.
 148
 149
 150 config LEGACY_PTY_COUNT
 151         int "Maximum number of legacy PTY in use"
 152         depends on LEGACY_PTYS
 153         default "256"
 154         ---help---
 155           The maximum number of legacy PTYs that can be used at any one time.
 156           The default is 256, and should be more than enough.  Embedded
 157           systems may want to reduce this to save memory.
 158
 159           When not in use, each legacy PTY occupies 12 bytes on 32-bit
 160           architectures and 24 bytes on 64-bit architectures.
 161
 162 config WATCHDOG
 163         bool "Watchdog Timer Support"
 164
 165 config WATCHDOG_NOWAYOUT
 166         bool "Disable watchdog shutdown on close"
 167         depends on WATCHDOG
 168
 169 config SOFT_WATCHDOG
 170         tristate "Software Watchdog"
 171         depends on WATCHDOG
 172
 173 config UML_WATCHDOG
 174         tristate "UML watchdog"
 175         depends on WATCHDOG
 176
 177 config UML_SOUND
 178         tristate "Sound support"
 179         help
 180         This option enables UML sound support.  If enabled, it will pull in
 181         soundcore and the UML hostaudio relay, which acts as a intermediary
 182         between the host's dsp and mixer devices and the UML sound system.
 183         It is safe to say 'Y' here.
 184
 185 config SOUND
 186         tristate
 187         default UML_SOUND
 188
 189 config HOSTAUDIO
 190         tristate
 191         default UML_SOUND
 192
 193 config UML_RANDOM
 194         tristate "Hardware random number generator"
 195         help
 196         This option enables UML's "hardware" random number generator.  It
 197         attaches itself to the host's /dev/random, supplying as much entropy
 198         as the host has, rather than the small amount the UML gets from its
 199         own drivers.  It registers itself as a standard hardware random number
 200         generator, major 10, minor 183, and the canonical device name is
 201         /dev/hwrng.
 202         The way to make use of this is to install the rng-tools package
 203         (check your distro, or download from
 204         http://sourceforge.net/projects/gkernel/).  rngd periodically reads
 205         /dev/hwrng and injects the entropy into /dev/random.
 206
 207 endmenu
 208