kernel - Introduce lightweight buffers
[dragonfly.git] / sys / boot / common / loader.8
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1.\" Copyright (c) 1999 Daniel C. Sobral
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\" notice, this list of conditions and the following disclaimer in the
11.\" documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
5ee58eed 25.\" $FreeBSD: src/sys/boot/common/loader.8,v 1.57 2003/06/29 20:57:55 brueffer Exp $
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26.\"
27.\" Note: The date here should be updated whenever a non-trivial
28.\" change is made to the manual page.
c5f72e80 29.Dd November 26, 2009
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30.Dt LOADER 8
31.Os
32.Sh NAME
33.Nm loader
34.Nd kernel bootstrapping final stage
35.Sh DESCRIPTION
36The program called
37.Nm
38is the final stage of
9bb2a92d 39.Dx Ns 's
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40kernel bootstrapping process.
41On IA32 (i386) architectures, it is a
42.Pa BTX
43client.
44It is linked statically to
45.Xr libstand 3
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46and located in the
47.Pa /boot
48or
49.Pa /
50directory.
51.Pp
52If a
53.Pa /boot
54directory exist on the boot file system, then
55.Dq /boot/
56is prepended to all relative file names used by
57.Nm .
58This makes it possible to locate all files used by
59.Nm
60in either
61.Pa /
62or
63.Pa /boot
64directory on the boot file system.
65If boot and root are the same file systems, then files used by
66.Nm
67are located in
984263bc 68.Pa /boot .
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69If boot and root are different file systems, then files used by
70.Nm
71are located in
72.Pa /
73on the boot file system, which is mounted as
74.Pa /boot
75on the root file system when the kernel is running.
984263bc 76.Pp
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77.Nm
78provides a scripting language that can be used to
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79automate tasks, do pre-configuration or assist in recovery
80procedures.
81This scripting language is roughly divided in
82two main components.
83The smaller one is a set of commands
84designed for direct use by the casual user, called "builtin
85commands" for historical reasons.
86The main drive behind these commands is user-friendliness.
87The bigger component is an
88.Tn ANS
5ee58eed 89Forth compatible Forth interpreter based on FICL, by
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90.An John Sadler .
91.Pp
92During initialization,
93.Nm
94will probe for a console and set the
95.Va console
96variable, or set it to serial console
97.Pq Dq comconsole
98if the previous boot stage used that.
99Then, devices are probed,
100.Va currdev
101and
102.Va loaddev
103are set, and
104.Va LINES
105is set to 24.
106Next,
107.Tn FICL
108is initialized, the builtin words are added to its vocabulary, and
2a2fb130 109.Pa boot.4th
5ee58eed 110is processed if it exists.
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111No disk switching is possible while that file is being read.
112The inner interpreter
113.Nm
114will use with
115.Tn FICL
116is then set to
117.Ic interpret ,
118which is
119.Tn FICL Ns 's
120default.
121After that,
2a2fb130 122.Pa loader.rc
984263bc 123is processed if available, and, failing that,
2a2fb130 124.Pa boot.conf
5ee58eed 125is read for historical reasons.
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126These files are processed through the
127.Ic include
128command, which reads all of them into memory before processing them,
129making disk changes possible.
130.Pp
131At this point, if an
132.Ic autoboot
133has not been tried, and if
134.Va autoboot_delay
135is not set to
136.Dq NO
137(not case sensitive), then an
138.Ic autoboot
139will be tried.
140If the system gets past this point,
141.Va prompt
142will be set and
143.Nm
144will engage interactive mode.
145.Sh BUILTIN COMMANDS
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146In
147.Nm ,
148builtin commands take parameters from the command line.
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149Presently,
150the only way to call them from a script is by using
151.Pa evaluate
152on a string.
153If an error condition occurs, an exception will be generated,
154which can be intercepted using
155.Tn ANS
156Forth exception handling
157words.
158If not intercepted, an error message will be displayed and
159the interpreter's state will be reset, emptying the stack and restoring
160interpreting mode.
161.Pp
162The builtin commands available are:
163.Pp
164.Bl -tag -width Ds -compact
165.It Ic autoboot Op Ar seconds
166Proceeds to bootstrap the system after a number of seconds, if not
167interrupted by the user.
168Displays a countdown prompt
169warning the user the system is about to be booted,
170unless interrupted by a key press.
171The kernel will be loaded first if necessary.
172Defaults to 10 seconds.
173.Pp
174.It Ic bcachestat
175Displays statistics about disk cache usage.
176For depuration only.
177.Pp
178.It Ic boot
179.It Ic boot Ar kernelname Op Cm ...
180.It Ic boot Fl flag Cm ...
181Immediately proceeds to bootstrap the system, loading the kernel
182if necessary.
183Any flags or arguments are passed to the kernel, but they
184must precede the kernel name, if a kernel name is provided.
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185Flags are described in
186.Xr boot 8 .
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187.Pp
188.Em WARNING :
189The behavior of this builtin is changed if
190.Xr loader.4th 8
191is loaded.
192.Pp
193.It Ic echo Xo
194.Op Fl n
195.Op Aq message
196.Xc
197Displays text on the screen.
198A new line will be printed unless
199.Fl n
200is specified.
201.Pp
202.It Ic heap
203Displays memory usage statistics.
204For debugging purposes only.
205.Pp
206.It Ic help Op topic Op subtopic
207Shows help messages read from
2a2fb130 208.Pa loader.help .
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209The special topic
210.Em index
211will list the topics available.
212.Pp
213.It Ic include Ar file Op Ar
214Process script files.
215Each file, in turn, is completely read into memory,
216and then each of its lines is passed to the command line interpreter.
217If any error is returned by the interpreter, the include
218command aborts immediately, without reading any other files, and
219returns an error itself (see
220.Sx ERRORS ) .
221.Pp
222.It Ic load Xo
223.Op Fl t Ar type
224.Ar file Cm ...
225.Xc
226Loads a kernel, kernel loadable module (kld), or file of opaque
227contents tagged as being of the type
228.Ar type .
229Kernel and modules can be either in a.out or ELF format.
230Any arguments passed after the name of the file to be loaded
231will be passed as arguments to that file.
232Currently, argument passing does not work for the kernel.
233.Pp
234.It Ic ls Xo
235.Op Fl l
236.Op Ar path
237.Xc
238Displays a listing of files in the directory
239.Ar path ,
240or the root directory if
241.Ar path
242is not specified.
243If
244.Fl l
245is specified, file sizes will be shown too.
246.Pp
247.It Ic lsdev Op Fl v
4f6dc91b 248Lists all devices with known file systems, where a
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249.Sq *
250prefix indicates a device from which it may be
4f6dc91b 251possible to load modules.
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252If
253.Fl v
254is specified, more details are printed.
255.Pp
256.It Ic lsmod Op Fl v
257Displays loaded modules.
258If
259.Fl v
260is specified, more details are shown.
261.Pp
262.It Ic more Ar file Op Ar
263Display the files specified, with a pause at each
264.Va LINES
265displayed.
266.Pp
267.It Ic pnpscan Op Fl v
268Scans for Plug-and-Play devices.
269This is not functional at present.
270.Pp
271.It Ic read Xo
272.Op Fl t Ar seconds
273.Op Fl p Ar prompt
274.Op Va variable
275.Xc
276Reads a line of input from the terminal, storing it in
277.Va variable
278if specified.
279A timeout can be specified with
280.Fl t ,
281though it will be canceled at the first key pressed.
282A prompt may also be displayed through the
283.Fl p
284flag.
285.Pp
286.It Ic reboot
287Immediately reboots the system.
288.Pp
289.It Ic set Ar variable
290.It Ic set Ar variable Ns = Ns Ar value
291Set loader's environment variables.
292.Pp
293.It Ic show Op Va variable
294Displays the specified variable's value, or all variables and their
295values if
296.Va variable
297is not specified.
298.Pp
299.It Ic unload
300Remove all modules from memory.
301.Pp
302.It Ic unset Va variable
303Removes
304.Va variable
305from the environment.
306.Pp
307.It Ic \&?
308Same as
309.Dq help index .
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310.El
311.Ss BUILTIN ENVIRONMENT VARIABLES
312The
313.Nm
314has actually two different kinds of
315.Sq environment
316variables.
317There are ANS Forth's
318.Em environmental queries ,
319and a separate space of environment variables used by builtins, which
320are not directly available to Forth words.
321It is the latter type that this section covers.
322.Pp
323Environment variables can be set and unset through the
324.Ic set
325and
326.Ic unset
327builtins, and can have their values interactively examined through the
328use of the
329.Ic show
330builtin.
331Their values can also be accessed as described in
332.Sx BUILTIN PARSER .
333.Pp
334Notice that these environment variables are not inherited by any shell
335after the system has been booted.
336.Pp
337A few variables are set automatically by
338.Nm .
339Others can affect the behavior of either
340.Nm
341or the kernel at boot.
342Some options may require a value,
343while others define behavior just by being set.
344Both types of builtin variables are described below.
345.Bl -tag -width bootfile
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346.It Va acpi_load
347Unset this to disable automatic loading of the ACPI module.
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348.It Va autoboot_delay
349Number of seconds
350.Ic autoboot
351will wait before booting.
352If this variable is not defined,
353.Ic autoboot
354will default to 10 seconds.
355.Pp
356If set to
357.Dq NO ,
358no
359.Ic autoboot
360will be automatically attempted after processing
2a2fb130 361.Pa loader.rc ,
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362though explicit
363.Ic autoboot Ns 's
364will be processed normally, defaulting to 10 seconds delay.
365.It Va boot_askname
366Instructs the kernel to prompt the user for the name of the root device
367when the kernel is booted.
368.It Va boot_ddb
369Instructs the kernel to start in the DDB debugger, rather than
370proceeding to initialize when booted.
371.It Va boot_gdb
372Selects gdb-remote mode for the kernel debugger by default.
373.It Va boot_single
374Prevents the kernel from initiating a multi-user startup; instead single-user
375mode will be entered when the kernel has finished device probing.
376.It Va boot_userconfig
377Requests that the kernel's interactive device configuration program
378be run when the kernel is booted.
379.It Va boot_verbose
380Setting this variable causes extra debugging information to be printed
381by the kernel during the boot phase.
382.It Va bootfile
383List of semicolon-separated search path for bootable kernels.
384The default is
385.Dq Li kernel;kernel.old .
386.It Va console
387Defines the current console.
388.It Va currdev
389Selects the default device.
390Syntax for devices is odd.
391.It Va init_path
392Sets the list of binaries which the kernel will try to run as the initial
393process.
394The first matching binary is used.
395The default list is
22628b14 396.Dq Li /sbin/init:/sbin/oinit:/sbin/init.bak .
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397.It Va interpret
398Has the value
bc65ccee 399.Dq Li OK
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400if the Forth's current state is interpreting.
401.It Va LINES
402Define the number of lines on the screen, to be used by the pager.
403.It Va module_path
404Sets the list of directories which will be searched for modules
405named in a load command or implicitly required by a dependency.
406The default value for this variable is
f4e821f3 407.Dq Li /boot;/boot/modules;/;/modules .
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408.It Va num_ide_disks
409Sets the number of IDE disks as a workaround for some problems in
410finding the root disk at boot.
411This has been deprecated in favor of
412.Va root_disk_unit .
413.It Va prompt
414Value of
415.Nm Ns 's
416prompt.
417Defaults to
bc65ccee 418.Dq Li "\e${interpret}" .
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419.It Va root_disk_unit
420If the code which detects the disk unit number for the root disk is
421confused, e.g. by a mix of SCSI and IDE disks, or IDE disks with
422gaps in the sequence (e.g. no primary slave), the unit number can
423be forced by setting this variable.
424.It Va rootdev
425By default the value of
426.Va currdev
5ee58eed 427is used to set the root file system
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428when the kernel is booted.
429This can be overridden by setting
430.Va rootdev
431explicitly.
432.It Va dumpdev
433The name of a device where the kernel can save a crash dump in case
434of a panic.
435This automatically sets the
436.Va kern.dumpdev
437.Xr sysctl 3
438MIB variable.
439.El
440.Pp
441Other variables are used to override kernel tunable parameters.
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442The following
443.Nm
444tunables are available:
984263bc 445.Bl -tag -width Va
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446.It Va hw.irq.X.dest
447Set irqX's destination to the given CPUID,
448which starts from 0.
449If the specified value is larger than the last CPUID,
450then the first CPUID will be used.
451This variable should not be used if IO/APIC support is not compiled
452into kernel.
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453.It Va hw.physmem
454Limit the amount of physical memory the system will use.
455By default the size is in bytes, but the
456.Cm k , K , m , M , g
457and
458.Cm G
459suffixes
460are also accepted and indicate kilobytes, megabytes and gigabytes
461respectively.
462An invalid suffix will result in the variable being ignored by the
463kernel.
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464.It Va hw.usb.hack_defer_exploration
465The USB keyboard will sometimes not attach properly unless you set this
42480ff5 466variable to 0.
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467.It Va kern.emergency_intr_enable
468Setting this to 1 enables emergency interrupt polling. All interrupt
469handlers are executed periodically. This mode is very expensive and should
470only be used to get a system accessible when interrupt routing is
3f5e28f4 471otherwise broken. It is primarily used by kernel developers to debug new
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472systems.
473.It Va kern.emergency_intr_freq
474Set the polling rate for the emergency interrupt polling code. The
475default is 10 (hz) to dissuade casual use. If you are doing real work
476with emergency interrupt polling mode enabled, it is recommended
477that you use a frequency between 100hz and 300hz.
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478.It Va kern.maxusers
479Set the size of a number of statically allocated system tables; see
480.Xr tuning 7
481for a description of how to select an appropriate value for this
482tunable.
483When set, this tunable replaces the value declared in the kernel
484compile-time configuration file.
485.It Va kern.ipc.nmbclusters
486Set the number of mbuf clusters to be allocated.
487The value cannot be set below the default
488determined when the kernel was compiled.
489Modifies
490.Va NMBCLUSTERS .
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491.It Va kern.mmxopt
492Toggles the mmx optimizations for the bcopy/copyin/copyout routines
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493.It Va kern.vm.kmem.size
494Sets the size of kernel memory (bytes).
5ee58eed 495This overrides the value determined when the kernel was compiled.
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496.It Va kern.maxswzone
497Limits the amount of KVM to be used to hold swap
498meta information, which directly governs the
499maximum amount of swap the system can support.
500This value is specified in bytes of KVA space
501and defaults to around 70MBytes.
502Care should be taken
503to not reduce this value such that the actual
aa0d550a 504amount of configured swap exceeds \(12 the
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505kernel-supported swap.
506The default 70MB allows
507the kernel to support a maximum of (approximately)
50814GB of configured swap.
509Only mess around with
510this parameter if you need to greatly extend the
511KVM reservation for other resources such as the
512buffer cache or
513.Va NMBCLUSTERS .
514Modifies
515.Va VM_SWZONE_SIZE_MAX .
516.It Va kern.maxbcache
517Limits the amount of KVM reserved for use by the
518buffer cache, specified in bytes.
519The default maximum is 200MB.
520This parameter is used to
521prevent the buffer cache from eating too much
522KVM in large-memory machine configurations.
523Only mess around with this parameter if you need to
524greatly extend the KVM reservation for other resources
525such as the swap zone or
526.Va NMBCLUSTERS .
527Note that
528the NBUF parameter will override this limit.
529Modifies
530.Va VM_BCACHE_SIZE_MAX .
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531.It Va machdep.disable_mtrrs
532Disable the use of i686 MTRRs (x86 only).
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533.It Va net.inet.tcp.tcbhashsize
534Overrides the compile-time set value of
535.Va TCBHASHSIZE
536or the preset default of 512.
537Must be a power of 2.
2a2fb130 538.It Va vfs.root.mountfrom
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539A semicolon separated list of partitions to try
540as the kernel root file system.
541Device format is file system type and partition,
542separated by colon.
543Used with boot-only partition, which is
544typically mounted on root file system as
746342c5 545.Pa /boot .
b27d3d3b
AH
546.Bl -hyphen
547.It
548One device example: "hammer:da8s1a"
549.It
550Several devices example: "ufs:da0s1a;hammer:ad1s1d"
551.El
552.Pp
553Each device in the list will be tried in the order specified
554until the mount succeeds.
555If all fail, the
556.Li mountroot>
557prompt is displayed for manual entry.
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558.Pp
559You may not specify devtab labels here but you can specify paths available
560to devfs such as "hammer:serno/L41JYE0G.s1d".
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561.El
562.Ss BUILTIN PARSER
563When a builtin command is executed, the rest of the line is taken
564by it as arguments, and it is processed by a special parser which
565is not used for regular Forth commands.
566.Pp
567This special parser applies the following rules to the parsed text:
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568.Bl -enum
569.It
570All backslash characters are preprocessed.
571.Bl -bullet
572.It
573\eb , \ef , \er , \en and \et are processed as in C.
574.It
575\es is converted to a space.
576.It
577\ev is converted to
578.Tn ASCII
57911.
580.It
581\ez is just skipped.
582Useful for things like
583.Dq \e0xf\ez\e0xf .
584.It
585\e0xN and \e0xNN are replaced by the hex N or NN.
586.It
587\eNNN is replaced by the octal NNN
588.Tn ASCII
589character.
590.It
591\e" , \e' and \e$ will escape these characters, preventing them from
592receiving special treatment in Step 2, described below.
593.It
594\e\e will be replaced with a single \e .
595.It
596In any other occurrence, backslash will just be removed.
597.El
598.It
599Every string between non-escaped quotes or double-quotes will be treated
600as a single word for the purposes of the remaining steps.
601.It
602Replace any
603.Li $VARIABLE
604or
605.Li ${VARIABLE}
606with the value of the environment variable
607.Va VARIABLE .
608.It
609Space-delimited arguments are passed to the called builtin command.
610Spaces can also be escaped through the use of \e\e .
611.El
612.Pp
613An exception to this parsing rule exists, and is described in
614.Sx BUILTINS AND FORTH .
615.Ss BUILTINS AND FORTH
616All builtin words are state-smart, immediate words.
617If interpreted, they behave exactly as described previously.
618If they are compiled, though,
619they extract their arguments from the stack instead of the command line.
620.Pp
621If compiled, the builtin words expect to find, at execution time, the
622following parameters on the stack:
623.D1 Ar addrN lenN ... addr2 len2 addr1 len1 N
624where
625.Ar addrX lenX
626are strings which will compose the command line that will be parsed
627into the builtin's arguments.
628Internally, these strings are concatenated in from 1 to N,
629with a space put between each one.
630.Pp
631If no arguments are passed, a 0
632.Em must
633be passed, even if the builtin accepts no arguments.
634.Pp
635While this behavior has benefits, it has its trade-offs.
636If the execution token of a builtin is acquired (through
637.Ic '
638or
639.Ic ['] ) ,
640and then passed to
641.Ic catch
642or
643.Ic execute ,
644the builtin behavior will depend on the system state
645.Bf Em
646at the time
647.Ic catch
648or
649.Ic execute
650is processed
651.Ef
652\&! This is particularly annoying for programs that want or need to
653handle exceptions.
654In this case, the use of a proxy is recommended.
655For example:
bc65ccee 656.Dl : (boot) boot \&;
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657.Sh FICL
658.Tn FICL
659is a Forth interpreter written in C, in the form of a forth
660virtual machine library that can be called by C functions and vice
661versa.
662.Pp
663In
664.Nm ,
665each line read interactively is then fed to
666.Tn FICL ,
667which may call
668.Nm
669back to execute the builtin words.
670The builtin
671.Ic include
672will also feed
673.Tn FICL ,
674one line at a time.
675.Pp
676The words available to
677.Tn FICL
678can be classified into four groups.
679The
680.Tn ANS
681Forth standard words, extra
682.Tn FICL
683words, extra
9bb2a92d 684.Dx
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685words, and the builtin commands;
686the latter were already described.
687The
688.Tn ANS
689Forth standard words are listed in the
690.Sx STANDARDS
691section.
692The words falling in the two other groups are described in the
693following subsections.
694.Ss FICL EXTRA WORDS
695.Bl -tag -width wid-set-super
696.It Ic .env
697.It Ic .ver
698.It Ic -roll
699.It Ic 2constant
700.It Ic >name
701.It Ic body>
702.It Ic compare
703This is the STRING word set's
704.Ic compare .
705.It Ic compile-only
706.It Ic endif
707.It Ic forget-wid
708.It Ic parse-word
709.It Ic sliteral
710This is the STRING word set's
711.Ic sliteral .
712.It Ic wid-set-super
713.It Ic w@
714.It Ic w!
715.It Ic x.
716.It Ic empty
717.It Ic cell-
718.It Ic -rot
719.El
bc65ccee 720.Ss DRAGONFLY EXTRA WORDS
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721.Bl -tag -width XXXXXXXX
722.It Ic \&$ Pq --
723Evaluates the remainder of the input buffer, after having printed it first.
724.It Ic \&% Pq --
725Evaluates the remainder of the input buffer under a
726.Ic catch
727exception guard.
728.It Ic .#
729Works like
730.Ic .
731but without outputting a trailing space.
732.It Ic fclose Pq Ar fd --
733Closes a file.
734.It Ic fkey Pq Ar fd -- char
735Reads a single character from a file.
736.It Ic fload Pq Ar fd --
737Processes a file
738.Em fd .
5ee58eed 739.It Ic fopen Pq Ar addr len mode Li -- Ar fd
984263bc 740Opens a file.
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741Returns a file descriptor, or \-1 in case of failure.
742The
743.Ar mode
744parameter selects whether the file is to be opened for read access, write
745access, or both.
746The constants
747.Dv O_RDONLY , O_WRONLY ,
748and
749.Dv O_RDWR
750are defined in
2a2fb130 751.Pa support.4th ,
5ee58eed 752indicating read only, write only, and read-write access, respectively.
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753.It Xo
754.Ic fread
755.Pq Ar fd addr len -- len'
756.Xc
757Tries to read
758.Em len
759bytes from file
760.Em fd
761into buffer
762.Em addr .
763Returns the actual number of bytes read, or -1 in case of error or end of
764file.
765.It Ic heap? Pq -- Ar cells
766Return the space remaining in the dictionary heap, in cells.
767This is not related to the heap used by dynamic memory allocation words.
768.It Ic inb Pq Ar port -- char
769Reads a byte from a port.
770.It Ic key Pq -- Ar char
771Reads a single character from the console.
772.It Ic key? Pq -- Ar flag
773Returns
774.Ic true
775if there is a character available to be read from the console.
776.It Ic ms Pq Ar u --
777Waits
778.Em u
779microseconds.
780.It Ic outb Pq Ar port char --
781Writes a byte to a port.
782.It Ic seconds Pq -- Ar u
783Returns the number of seconds since midnight.
784.It Ic tib> Pq -- Ar addr len
785Returns the remainder of the input buffer as a string on the stack.
786.It Ic trace! Pq Ar flag --
787Activates or deactivates tracing.
788Does not work with
789.Ic catch .
790.El
bc65ccee 791.Ss DRAGONFLY DEFINED ENVIRONMENTAL QUERIES
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792.Bl -tag -width Ds
793.It arch-i386
794.Ic TRUE
795if the architecture is IA32.
9bb2a92d
HP
796.It DragonFly_version
797.Dx
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798version at compile time.
799.It loader_version
800.Nm
801version.
802.El
803.Ss SYSTEM DOCUMENTATION
804.Sh FILES
805.Bl -tag -width /boot/defaults/loader.conf -compact
806.It Pa /boot/loader
807.Nm
808itself.
809.It Pa /boot/boot.4th
810Additional
811.Tn FICL
812initialization.
813.It Pa /boot/boot.conf
814.Nm
815bootstrapping script.
816Deprecated.
817.It Pa /boot/defaults/loader.conf
818.It Pa /boot/loader.conf
819.It Pa /boot/loader.conf.local
820.Nm
821configuration files, as described in
822.Xr loader.conf 5 .
823.It Pa /boot/loader.rc
824.Nm
825bootstrapping script.
826.It Pa /boot/loader.help
827Loaded by
828.Ic help .
829Contains the help messages.
830.El
831.Sh EXAMPLES
832Boot in single user mode:
833.Pp
834.Dl boot -s
835.Pp
836Load kernel's user configuration file.
837Notice that a kernel must be loaded before any other
838.Ic load
839command is attempted.
840.Bd -literal -offset indent
841load kernel
2a2fb130 842load -t userconfig_script kernel.conf
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843.Ed
844.Pp
845Load the kernel, a splash screen, and then autoboot in five seconds.
846.Bd -literal -offset indent
847load kernel
848load splash_bmp
2a2fb130 849load -t splash_image_data chuckrulez.bmp
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850autoboot 5
851.Ed
852.Pp
853Set the disk unit of the root device to 2, and then boot.
854This would be needed in a system with two IDE disks,
601c6213 855with the second IDE disk hardwired to ad2 instead of ad1.
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856.Bd -literal -offset indent
857set root_disk_unit=2
2a2fb130 858boot kernel
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859.Ed
860.Pp
861See also:
862.Bl -tag -width /usr/share/examples/bootforth/X
2a2fb130 863.It Pa loader.4th
984263bc 864Extra builtin-like words.
2a2fb130 865.It Pa support.4th
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866.Pa loader.conf
867processing words.
868.It Pa /usr/share/examples/bootforth/
869Assorted examples.
870.El
871.Sh ERRORS
872The following values are thrown by
873.Nm :
874.Bl -tag -width XXXXX -offset indent
875.It 100
876Any type of error in the processing of a builtin.
877.It -1
878.Ic Abort
879executed.
880.It -2
881.Ic Abort"
882executed.
883.It -56
884.Ic Quit
885executed.
886.It -256
887Out of interpreting text.
888.It -257
889Need more text to succeed -- will finish on next run.
890.It -258
891.Ic Bye
892executed.
893.It -259
894Unspecified error.
895.El
896.Sh SEE ALSO
897.Xr libstand 3 ,
898.Xr loader.conf 5 ,
899.Xr tuning 7 ,
900.Xr boot 8 ,
bc65ccee 901.Xr btxld 8 ,
24d322d7
TN
902.Xr loader.4th 8 ,
903.Xr sysctl 8
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904.Sh STANDARDS
905For the purposes of ANS Forth compliance, loader is an
906.Bf Em
907ANS Forth System with Environmental Restrictions, Providing
908.Ef
909.Bf Li
910.No .( ,
911.No :noname ,
912.No ?do ,
913parse, pick, roll, refill, to, value, \e, false, true,
914.No <> ,
915.No 0<> ,
916compile\&, , erase, nip, tuck
917.Ef
918.Em and
919.Li marker
920.Bf Em
921from the Core Extensions word set, Providing the Exception Extensions
922word set, Providing the Locals Extensions word set, Providing the
923Memory-Allocation Extensions word set, Providing
924.Ef
925.Bf Li
926\&.s,
927bye, forget, see, words,
928\&[if],
929\&[else]
930.Ef
931.Em and
932.Li [then]
933.Bf Em
934from the Programming-Tools extension word set, Providing the
935Search-Order extensions word set.
936.Ef
937.Sh HISTORY
5ee58eed 938The
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939.Nm
940first appeared in
941.Fx 3.1 .
942.Sh AUTHORS
943.An -nosplit
5ee58eed 944The
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945.Nm
946was written by
947.An Michael Smith Aq msmith@FreeBSD.org .
948.Pp
949.Tn FICL
950was written by
951.An John Sadler Aq john_sadler@alum.mit.edu .
952.Sh BUGS
953The
954.Ic expect
955and
956.Ic accept
957words will read from the input buffer instead of the console.
958The latter will be fixed, but the former will not.