vserver 1.9.3

[linux-2.6.git] / arch / um / Kconfig_char

diff --git a/arch/um/Kconfig_char b/arch/um/Kconfig_char
index a21cbbc..09f4738 100644 (file)
--- a/arch/um/Kconfig_char
+++ b/arch/um/Kconfig_char
@@ -72,6 +72,10 @@ config XTERM_CHAN
         well, since UML's gdb currently requires an xterm.
         It is safe to say 'Y' here.
 
+config NOCONFIG_CHAN
+       bool
+       default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && FD_CHAN && NULL_CHAN)
+
 config CON_ZERO_CHAN
        string "Default main console channel initialization"
        default "fd:0,fd:1"
@@ -108,11 +112,55 @@ config SSL_CHAN
 
 config UNIX98_PTYS
        bool "Unix98 PTY support"
-
-config UNIX98_PTY_COUNT
-       int "Maximum number of Unix98 PTYs in use (0-2048)"
-       depends on UNIX98_PTYS
+       ---help---
+         A pseudo terminal (PTY) is a software device consisting of two
+         halves: a master and a slave. The slave device behaves identical to
+         a physical terminal; the master device is used by a process to
+         read data from and write data to the slave, thereby emulating a
+         terminal. Typical programs for the master side are telnet servers
+         and xterms.
+
+         Linux has traditionally used the BSD-like names /dev/ptyxx for
+         masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
+         has a number of problems. The GNU C library glibc 2.1 and later,
+         however, supports the Unix98 naming standard: in order to acquire a
+         pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
+         terminal is then made available to the process and the pseudo
+         terminal slave can be accessed as /dev/pts/<number>. What was
+         traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
+
+         All modern Linux systems use the Unix98 ptys.  Say Y unless
+         you're on an embedded system and want to conserve memory.
+
+config LEGACY_PTYS
+       bool "Legacy (BSD) PTY support"
+       default y
+       ---help---
+         A pseudo terminal (PTY) is a software device consisting of two
+         halves: a master and a slave. The slave device behaves identical to
+         a physical terminal; the master device is used by a process to
+         read data from and write data to the slave, thereby emulating a
+         terminal. Typical programs for the master side are telnet servers
+         and xterms.
+
+         Linux has traditionally used the BSD-like names /dev/ptyxx
+         for masters and /dev/ttyxx for slaves of pseudo
+         terminals. This scheme has a number of problems, including
+         security.  This option enables these legacy devices; on most
+         systems, it is safe to say N.
+
+
+config LEGACY_PTY_COUNT
+       int "Maximum number of legacy PTY in use"
+       depends on LEGACY_PTYS
        default "256"
+       ---help---
+         The maximum number of legacy PTYs that can be used at any one time.
+         The default is 256, and should be more than enough.  Embedded
+         systems may want to reduce this to save memory.
+
+         When not in use, each legacy PTY occupies 12 bytes on 32-bit
+         architectures and 24 bytes on 64-bit architectures.
 
 config WATCHDOG
        bool "Watchdog Timer Support"