105
104
this if you expect the UML that you build to be run in environments
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105
which don't have a set of /dev/pty* devices.
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bool "Unix98 PTY support"
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A pseudo terminal (PTY) is a software device consisting of two
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halves: a master and a slave. The slave device behaves identical to
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a physical terminal; the master device is used by a process to
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read data from and write data to the slave, thereby emulating a
115
terminal. Typical programs for the master side are telnet servers
118
Linux has traditionally used the BSD-like names /dev/ptyxx for
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masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
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has a number of problems. The GNU C library glibc 2.1 and later,
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however, supports the Unix98 naming standard: in order to acquire a
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pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
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terminal is then made available to the process and the pseudo
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terminal slave can be accessed as /dev/pts/<number>. What was
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traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
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All modern Linux systems use the Unix98 ptys. Say Y unless
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you're on an embedded system and want to conserve memory.
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bool "Legacy (BSD) PTY support"
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A pseudo terminal (PTY) is a software device consisting of two
135
halves: a master and a slave. The slave device behaves identical to
136
a physical terminal; the master device is used by a process to
137
read data from and write data to the slave, thereby emulating a
138
terminal. Typical programs for the master side are telnet servers
141
Linux has traditionally used the BSD-like names /dev/ptyxx
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for masters and /dev/ttyxx for slaves of pseudo
143
terminals. This scheme has a number of problems, including
144
security. This option enables these legacy devices; on most
145
systems, it is safe to say N.
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tristate "RAW driver (/dev/raw/rawN)"
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The raw driver permits block devices to be bound to /dev/raw/rawN.
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Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
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See the raw(8) manpage for more details.
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Applications should preferably open the device (eg /dev/hda1)
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with the O_DIRECT flag.
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int "Maximum number of RAW devices to support (1-8192)"
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depends on RAW_DRIVER
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The maximum number of RAW devices that are supported.
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Default is 256. Increase this number in case you need lots of
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config LEGACY_PTY_COUNT
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int "Maximum number of legacy PTY in use"
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depends on LEGACY_PTYS
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The maximum number of legacy PTYs that can be used at any one time.
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The default is 256, and should be more than enough. Embedded
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systems may want to reduce this to save memory.
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When not in use, each legacy PTY occupies 12 bytes on 32-bit
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architectures and 24 bytes on 64-bit architectures.
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bool "Watchdog Timer Support"
182
config WATCHDOG_NOWAYOUT
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bool "Disable watchdog shutdown on close"
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tristate "Software Watchdog"
191
tristate "UML watchdog"
195
108
tristate "Sound support"
212
125
default UML_SOUND
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#It is selected elsewhere, so kconfig would warn without this.
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tristate "Hardware random number generator"
222
This option enables UML's "hardware" random number generator. It
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attaches itself to the host's /dev/random, supplying as much entropy
224
as the host has, rather than the small amount the UML gets from its
225
own drivers. It registers itself as a standard hardware random number
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generator, major 10, minor 183, and the canonical device name is
228
The way to make use of this is to install the rng-tools package
229
(check your distro, or download from
230
http://sourceforge.net/projects/gkernel/). rngd periodically reads
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/dev/hwrng and injects the entropy into /dev/random.
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tristate "iomem emulation driver"
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This driver allows a host file to be used as emulated IO memory inside