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34 To compile support for this ABI into an i386 kernel
35 place the following line in your
36 kernel configuration file:
37 .Bd -ragged -offset indent
38 .Cd "options COMPAT_LINUX"
41 for an amd64 kernel use:
42 .Bd -ragged -offset indent
43 .Cd "options COMPAT_LINUX32"
46 Alternatively, to load the ABI as a
47 module at boot time, place the following line in
49 .Bd -literal -offset indent
55 module provides limited Linux ABI (application binary interface) compatibility,
56 making it possible to run many unmodified Linux applications and libraries
57 without the need for virtualization or emulation.
58 Some of the facilities provided are:
66 Special signal handling for activated images
68 Linux to native system call translation
70 Linux-specific system calls
73 Note that dynamically linked Linux executables
74 will require a suitable environment in
76 This includes native Linux shared libraries, and Linux-specific virtual
78 To set it up, install the
79 .Pa emulators/linux_base-c7
80 port or the linux_base-c7
81 package, and add the following line to the
85 .Dl linux_enable="YES"
87 To avoid mounting Linux-specific filesystems at startup, also add the following
90 .Dl linux_mounts_enable="NO"
92 The following variables are available as both
97 .Bl -tag -width indent
98 .It Va compat.linux.debug
99 Enable debugging messages.
100 Set to 0 to silence them.
102 A setting of 1 prints debug messages, tells about unimplemented stuff (only
104 Set to 2 is like 1, but also prints messages about implemented but not tested
106 Setting it to 3 or higher is like 2, but no rate limiting of messages.
107 .It Va compat.linux.default_openfiles
108 Default soft openfiles resource limit for Linux applications.
109 Set to -1 to disable the limit.
111 .It Va compat.linux.emul_path
112 Path to the Linux run-time environment.
115 .It Va compat.linux.osname
116 Linux kernel operating system name.
117 .It Va compat.linux.osrelease
118 Linux kernel operating system release.
119 Changing this to something else is discouraged on non-development systems,
120 because it may change the way Linux programs work.
121 Recent versions of GNU libc are known to use different syscalls depending
122 on the value of this sysctl.
123 .It Va compat.linux.oss_version
124 Linux Open Sound System version.
125 .It Va compat.linux.preserve_vstatus
126 When set to 1, it prevents Linux applications from resetting the
129 From a user perspective, this makes
131 work for Linux executables.
135 .Bl -tag -width /compat/linux/dev/shm -compact
137 minimal Linux run-time environment
138 .It Pa /compat/linux/dev
139 device file system, see
141 .It Pa /compat/linux/dev/fd
142 file descriptor file system mounted with the
146 .It Pa /compat/linux/dev/shm
147 in-memory file system, see
149 .It Pa /compat/linux/proc
150 Linux process file system, see
152 .It Pa /compat/linux/sys
153 Linux kernel objects file system, see
165 Linux ABI support first appeared in
168 Support for some of the Linux-specific system calls and system call arguments