1 SYSTEM(4) File Formats and Configurations SYSTEM(4)
2
3
4
5 NAME
6 system - system configuration information file
7
8 DESCRIPTION
9 The system file is used for customizing the operation of the operating
10 system kernel. The recommended procedure is to preserve the original
11 system file before modifying it.
12
13
14 It is not recommended to edit the /etc/system file directly but rather
15 to deliver configuration fragments into files under /etc/system.d;
16 files in this directory are combined in alphabetical order and read by
17 the kernel before /etc/system is processed. Directives in /etc/system
18 therefore take precedence over any settings delivered in fragment
19 files.
20
21
22 The recommended naming schema for the fragment files is to use the name
23 of the package which is delivering the file with '/' characters
24 replaced by ':'; file names that start with a dot (.) will be ignored.
25
26
27 If /etc/system.d/ exists and contains any fragment files, then the
28 directory must also be writable or it will not be possible to create or
29 update the system boot archive.
30
31
32 The system file contains commands which are read by the kernel during
33 initialization and used to customize the operation of your system.
34 These commands are useful for modifying the system's treatment of its
35 loadable kernel modules.
36
37
38 The syntax of the system file consists of a list of keyword/value pairs
39 which are recognized by the system as valid commands. Comment lines
40 must begin with an asterisk (*) or a hash mark (#) and end with a
41 newline character. All commands are case-insensitive except where
42 noted.
43
44
45 Commands that modify the system's operation with respect to loadable
46 kernel modules require you to specify the module type by listing the
47 module's namespace. The following namespaces are currently supported on
48 all platforms:
49
50 drv
51 Modules in this namespace are device drivers.
52
53
54 exec
55 Modules in this namespace are execution format modules. The
56 following exec modules are currently provided:
57
58 Only on SPARC system:
59
60 aoutexec
61
62
63
64
65 Only on x86 system:
66
67 coffexec
68
69
70
71
72 On SPARC and IA systems:
73
74 elfexec
75 intpexec
76 javaexec
77
78
79
80
81
82 firmware
83 Raw firmware images in subdirectories, one for each device
84 driver module using firmload(9F).
85
86
87 fs
88 These modules are filesystems.
89
90
91 sched
92 These modules implement a process scheduling algorithm.
93
94
95 strmod
96 These modules are STREAMS modules.
97
98
99 sys
100 These modules implement loadable system-call modules.
101
102
103 misc
104 These modules do not fit into any of the above categories, so
105 are considered "miscellaneous" modules.
106
107
108
109 SPARC only:
110
111 dacf
112 These modules provide rules and actions for device auto-
113 configuration.
114
115
116 tod
117 These modules provide support for the time of day hardware.
118
119
120 cpu
121 These modules provide CPU-specific kernel routines.
122
123
124
125 A description of each of the supported commands follows:
126
127 exclude: <namespace>/<modulename>
128
129 Do not allow the listed loadable kernel module to be loaded.
130 exclude commands are cumulative; the list of modules to exclude is
131 created by combining every exclude entry in the system file.
132
133
134 include: <namespace>/<modulename>
135
136 Include the listed loadable kernel module. This is the system's
137 default, so using include does not modify the system's operation.
138 include commands are cumulative.
139
140
141 forceload: <namespace>/<modulename>
142
143 Force this kernel module to be loaded during kernel initialization.
144 The default action is to automatically load the kernel module when
145 its services are first accessed. forceload commands are cumulative.
146
147
148 rootdev: <device name>
149
150 Set the root device to the listed value instead of using the
151 default root device as supplied by the boot program.
152
153
154 rootfs: <root filesystem type>
155
156 Set the root filesystem type to the listed value.
157
158
159 moddir: <first module path>[[{:, }<second ...>]...]
160
161 Set the search path for loadable kernel modules. This command
162 operates very much like the PATH shell variable. Multiple
163 directories to search can be listed together, delimited either by
164 blank spaces or colons.
165
166
167 set [<module>:]<symbol> {=, |, &} [~][-]<value>
168
169 Set an integer or character pointer in the kernel or in the
170 selected kernel module to a new value. This command is used to
171 change kernel and module parameters and thus modify the operation
172 of your system. Assignment operations are not cumulative, whereas
173 bitwise AND and OR operations are cumulative.
174
175 Operations that are supported for modifying integer variables are:
176 simple assignment, inclusive bitwise OR, bitwise AND, one's
177 complement, and negation. Variables in a specific loadable module
178 can be targeted for modification by specifying the variable name
179 prefixed with the kernel module name and a colon (:) separator.
180 Values can be specified as hexadecimal (0x10), Octal (046), or
181 Decimal (5).
182
183 The only operation supported for modifying character pointers is
184 simple assignment. Static string data such as character arrays
185 cannot be modified using the set command. Use care and ensure that
186 the variable you are modifying is in fact a character pointer. The
187 set command is very powerful, and will likely cause problems if
188 used carelessly. The following escape sequences are supported
189 within the quoted string:
190
191 \n (newline)
192 \t (tab)
193 \b (backspace)
194
195
196
197
198 EXAMPLES
199 Example 1 A sample system file.
200
201
202 The following is a sample system file.
203
204
205 * Force the ELF exec kernel module to be loaded during kernel
206 * initialization. Execution type modules are in the exec namespace.
207 forceload: exec/elfexec
208 * Change the root device to /sbus@1,f8000000/esp@0,800000/sd@3,0:a.
209 * You can derive root device names from /devices.
210 * Root device names must be the fully expanded Open Boot Prom
211 * device name. This command is platform and configuration specific.
212 * This example uses the first partition (a) of the SCSI disk at
213 * SCSI target 3 on the esp host adapter in slot 0 (on board)
214 * of the SBus of the machine.
215 * Adapter unit-address 3,0 at sbus unit-address 0,800000.
216 rootdev: /sbus@1,f8000000/esp@0,800000/sd@3,0:a
217 * Set the filesystem type of the root to ufs. Note that
218 * the equal sign can be used instead of the colon.
219 rootfs:ufs
220 * Set the search path for kernel modules to look first in
221 * /usr/phil/mod_test for modules, then in /kernel/modules (the
222 * default) if not found. Useful for testing new modules.
223 * Note that you can delimit your module pathnames using
224 * colons instead of spaces: moddir:/newmodules:/kernel/modules
225 moddir:/usr/phil/mod_test /kernel/modules.
226 * Set the configuration option {_POSIX_CHOWN_RESTRICTED} :
227 * This configuration option is enabled by default.
228 set rstchown = 1
229 * Disable the configuration option {_POSIX_CHOWN_RESTRICTED} :
230 set rstchown = 0
231 * Turn on debugging messages in the modules mydriver. This is useful
232 * during driver development.
233 set mydriver:debug = 1
234 * Bitwise AND the kernel variable "moddebug" with the
235 * one's complement of the hex value 0x880, and set
236 * "moddebug" to this new value.
237 set moddebug & ~0x880
238 * Demonstrate the cumulative effect of the SET
239 * bitwise AND/OR operations by further modifying "moddebug"
240 * by ORing it with 0x40.
241 set moddebug | 0x40
242
243
244
245 SEE ALSO
246 boot(1M), init(1M), kernel(1M)
247
248 WARNINGS
249 Use care when modifying the system file; it modifies the operation of
250 the kernel. If you preserved the original system file, you can boot
251 using boot -a, which will ask you to specify the path to the saved
252 file. This should allow the system to boot correctly. If you cannot
253 locate a system file that will work, you may specify /dev/null. This
254 acts as an empty system file, and the system will attempt to boot using
255 its default settings.
256
257 NOTES
258 The system files are read only once, at boot time.
259
260
261
262 January 29, 2019 SYSTEM(4)