xref: /freebsd/share/man/man4/linux.4 (revision 462171d9aa00f863df65ac49836c9f3cc7e55a9c)
1e6769554SRui Paulo.\" Copyright (c) 2000 Sheldon Hearn
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25e6769554SRui Paulo.\" $FreeBSD$
26e6769554SRui Paulo.\"
27*462171d9SEdward Tomasz Napierala.Dd June 12, 2020
28c383d55bSGavin Atkinson.Dt LINUX 4
29e6769554SRui Paulo.Os
30e6769554SRui Paulo.Sh NAME
31e6769554SRui Paulo.Nm linux
32e6769554SRui Paulo.Nd Linux ABI support
33e6769554SRui Paulo.Sh SYNOPSIS
3439eb4bc6SBernhard SchmidtTo compile support for this ABI into an i386 kernel
35e6769554SRui Pauloplace the following line in your
36e6769554SRui Paulokernel configuration file:
37e6769554SRui Paulo.Bd -ragged -offset indent
38e6769554SRui Paulo.Cd "options COMPAT_LINUX"
39e6769554SRui Paulo.Ed
40e6769554SRui Paulo.Pp
4139eb4bc6SBernhard Schmidtfor an amd64 kernel use:
4239eb4bc6SBernhard Schmidt.Bd -ragged -offset indent
4339eb4bc6SBernhard Schmidt.Cd "options COMPAT_LINUX32"
4439eb4bc6SBernhard Schmidt.Ed
4539eb4bc6SBernhard Schmidt.Pp
46e6769554SRui PauloAlternatively, to load the ABI as a
47e6769554SRui Paulomodule at boot time, place the following line in
48e6769554SRui Paulo.Xr loader.conf 5 :
49e6769554SRui Paulo.Bd -literal -offset indent
50e6769554SRui Paulolinux_load="YES"
51e6769554SRui Paulo.Ed
52e6769554SRui Paulo.Sh DESCRIPTION
53e6769554SRui PauloThe
54e6769554SRui Paulo.Nm
55f54d9519SEdward Tomasz Napieralamodule provides limited Linux ABI (application binary interface) compatibility,
56f54d9519SEdward Tomasz Napieralamaking it possible to run many unmodified Linux applications and libraries
57f54d9519SEdward Tomasz Napieralawithout the need for virtualization or emulation.
58f54d9519SEdward Tomasz NapieralaSome of the facilities provided are:
59e6769554SRui Paulo.Bl -bullet
60e6769554SRui Paulo.It
61e6769554SRui PauloAn image activator
62e6769554SRui Paulofor correctly branded
63e6769554SRui Paulo.Xr elf 5
64e6769554SRui Pauloexecutable images
65e6769554SRui Paulo.It
66e6769554SRui PauloSpecial signal handling for activated images
67e6769554SRui Paulo.It
68e6769554SRui PauloLinux to native system call translation
69f54d9519SEdward Tomasz Napierala.It
70f54d9519SEdward Tomasz NapieralaLinux-specific system calls
71e6769554SRui Paulo.El
72e6769554SRui Paulo.Pp
73f54d9519SEdward Tomasz NapieralaNote that dynamically linked Linux executables
74f54d9519SEdward Tomasz Napieralawill require a suitable environment in
75f54d9519SEdward Tomasz Napierala.Pa /compat/linux .
76f54d9519SEdward Tomasz NapieralaThis includes native Linux shared libraries, and Linux-specific virtual
77f54d9519SEdward Tomasz Napieralafilesystems.
78f54d9519SEdward Tomasz NapieralaTo set it up, install the
79f54d9519SEdward Tomasz Napierala.Pa emulators/linux_base-c7
80f54d9519SEdward Tomasz Napieralaport or the linux_base-c7
81f54d9519SEdward Tomasz Napieralapackage, and add the following line to the
82f54d9519SEdward Tomasz Napierala.Xr rc.conf 5
83f54d9519SEdward Tomasz Napieralafile:
84e6769554SRui Paulo.Pp
85f54d9519SEdward Tomasz Napierala.Dl linux_enable="YES"
86f54d9519SEdward Tomasz Napierala.Pp
87f54d9519SEdward Tomasz NapieralaTo avoid mounting Linux-specific filesystems at startup, also add the following
88f54d9519SEdward Tomasz Napieralaline:
89f54d9519SEdward Tomasz Napierala.Pp
90f54d9519SEdward Tomasz Napierala.Dl linux_mounts_enable="NO"
91f54d9519SEdward Tomasz Napierala.Sh SYSCTL VARIABLES
92f54d9519SEdward Tomasz NapieralaThe following variables are available as both
93e6769554SRui Paulo.Xr sysctl 8
94f54d9519SEdward Tomasz Napieralavariables and
95f54d9519SEdward Tomasz Napierala.Xr loader 8
96f54d9519SEdward Tomasz Napieralatunables:
97f54d9519SEdward Tomasz Napierala.Bl -tag -width indent
98*462171d9SEdward Tomasz Napierala.It Va compat.linux.debug
99*462171d9SEdward Tomasz NapieralaEnable debugging messages.
100*462171d9SEdward Tomasz NapieralaSet to 0 to silence them.
101*462171d9SEdward Tomasz NapieralaDefaults to 1.
1028c5059e9SEdward Tomasz Napierala.It Va compat.linux.default_openfiles
1038c5059e9SEdward Tomasz NapieralaDefault soft openfiles resource limit for Linux applications.
1048c5059e9SEdward Tomasz NapieralaSet to -1 to disable the limit.
1058c5059e9SEdward Tomasz NapieralaDefaults to 1024.
106b5f20658SEdward Tomasz Napierala.It Va compat.linux.emul_path
107b5f20658SEdward Tomasz NapieralaPath to the Linux run-time environment.
108b5f20658SEdward Tomasz NapieralaDefaults to
109b5f20658SEdward Tomasz Napierala.Pa /compat/linux .
110f54d9519SEdward Tomasz Napierala.It Va compat.linux.osname
111e6769554SRui PauloLinux kernel operating system name.
112f54d9519SEdward Tomasz Napierala.It Va compat.linux.osrelease
113e6769554SRui PauloLinux kernel operating system release.
114e6769554SRui PauloChanging this to something else is discouraged on non-development systems,
115e6769554SRui Paulobecause it may change the way Linux programs work.
116e6769554SRui PauloRecent versions of GNU libc are known to use different syscalls depending
117e6769554SRui Pauloon the value of this sysctl.
118f54d9519SEdward Tomasz Napierala.It Va compat.linux.oss_version
119e6769554SRui PauloLinux Open Sound System version.
1202cf9eb6cSEdward Tomasz Napierala.It Va compat.linux.preserve_vstatus
1212cf9eb6cSEdward Tomasz NapieralaWhen set to 1, it prevents Linux applications from resetting the
1222cf9eb6cSEdward Tomasz Napierala.Xr termios 4
1232cf9eb6cSEdward Tomasz NapieralaVSTATUS setting.
1242cf9eb6cSEdward Tomasz NapieralaFrom a user perspective, this makes
1252cf9eb6cSEdward Tomasz Napierala.Va SIGINFO
1262cf9eb6cSEdward Tomasz Napieralawork for Linux executables.
1272cf9eb6cSEdward Tomasz NapieralaDefaults to 0.
128e6769554SRui Paulo.Sh FILES
129f54d9519SEdward Tomasz Napierala.Bl -tag -width /compat/linux/dev/shm -compact
130e6769554SRui Paulo.It Pa /compat/linux
131e6769554SRui Paulominimal Linux run-time environment
13277d3337cSDmitry Chagin.It Pa /compat/linux/dev/fd
133f54d9519SEdward Tomasz Napieralafile-descriptor file system, see
134f54d9519SEdward Tomasz Napierala.Xr fdescfs 5
135f54d9519SEdward Tomasz Napierala.It Pa /compat/linux/dev/shm
136f54d9519SEdward Tomasz Napieralain-memory file system, see
137f54d9519SEdward Tomasz Napierala.Xr tmpfs 5
138e6769554SRui Paulo.It Pa /compat/linux/proc
139f54d9519SEdward Tomasz NapieralaLinux process file system, see
140f54d9519SEdward Tomasz Napierala.Xr linprocfs 5
141e6769554SRui Paulo.It Pa /compat/linux/sys
142f54d9519SEdward Tomasz NapieralaLinux kernel objects file system, see
143f54d9519SEdward Tomasz Napierala.Xr linsysfs 5
144e6769554SRui Paulo.El
145e6769554SRui Paulo.Sh SEE ALSO
146e6769554SRui Paulo.Xr brandelf 1 ,
147fd2ced61SEdward Tomasz Napierala.Xr pty 4 ,
148e6769554SRui Paulo.Xr elf 5 ,
14977d3337cSDmitry Chagin.Xr fdescfs 5 ,
150e6769554SRui Paulo.Xr linprocfs 5 ,
151f54d9519SEdward Tomasz Napierala.Xr linsysfs 5 ,
152f54d9519SEdward Tomasz Napierala.Xr tmpfs 5
153e6769554SRui Paulo.Sh HISTORY
154e6769554SRui PauloLinux ABI support first appeared in
155e6769554SRui Paulo.Fx 2.1 .
156f54d9519SEdward Tomasz Napierala.Sh BUGS
157f54d9519SEdward Tomasz NapieralaSupport for some of the Linux-specific system calls and system call arguments
158f54d9519SEdward Tomasz Napieralais missing.
159