X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fum%2FKconfig_char;h=09f47388c7c5ea148d054154c0a8e3c8cf1a2d61;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=a21cbbc7efde6c9bc1311c71b8cc97a26814a71a;hpb=a2c21200f1c81b08cb55e417b68150bba439b646;p=linux-2.6.git

diff --git a/arch/um/Kconfig_char b/arch/um/Kconfig_char
index a21cbbc7e..09f47388c 100644
--- 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"