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Applied fixes for markup and spacing in manual pages.

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Patch provided by Mario Blattermann.

Added translation framework (po4a) from Mario Blttermann.
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Jesse
2021-12-27 16:14:42 -04:00
parent 933ce33854
commit 92d4b0e74a
24 changed files with 9963 additions and 285 deletions
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76
man/initctl.5
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@@ -14,23 +14,23 @@
.\" along with this program; if not, write to the Free Software
.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
.\"
.TH INITCTL 5 "April 13, 2018" "" "Linux System Administrator's Manual"
.TH INITCTL 5 "April 13, 2018" "sysvinit @VERSION@" "File Formats"
.SH NAME
initctl \- /run/initctl is a named pipe which passes commands to SysV init.
initctl \- /run/initctl is a named pipe which passes commands to SysV init
.SH SYNOPSIS
/run/initctl
.SH DESCRIPTION
This document describes the communiction pipe set up by SysV init
at /run/initctl. This named pipe allows programs with the proper
This document describes the communication pipe set up by SysV \fBinit\fR
at \fI/run/initctl\fR. This named pipe allows programs with the proper
permissions (typically programs run by root have read+write access to
the pipe) to send signals to the init program (PID 1).
the pipe) to send signals to the \fBinit\fR program (PID 1).
The init manual page has, up until recently, simply stated
that people wishing to understand how to send messages to init
The \fBinit\fR manual page has, up until recently, simply stated
that people wishing to understand how to send messages to \fBinit\fR
should read the init program's source code, but that is not usually practical.
Messages sent to the pipe to talk to init must have a special format.
Messages sent to the pipe to talk to \fBinit\fR must have a special format.
This format is defined as a C structure and the technical break-down
is presented here:
@@ -56,10 +56,10 @@ struct init_request {
Let's go through the init_request structure one line at a time. The
first variable, the "magic" number must be of the value 0x03091969.
The init program then knows that only programs with root access which send
The \fBinit\fR program then knows that only programs with root access which send
this magic number are authorized to communicate with init.
The cmd variable is a value in the range of 0-8 (currently). This cmd
The \fIcmd\fR variable is a value in the range of 0-8 (currently). This \fIcmd\fR
variable tells init what we want it to do. Here are the possible options:
1 - Set the current runlevel, specified by the runlevel variable.
@@ -71,31 +71,31 @@ variable tells init what we want it to do. Here are the possible options:
4 - The power is okay, cancel shutdown.
6 - Set an environment variable to a value to be specified in
the data variable of this structure.
the \fIdata\fR variable of this structure.
Other cmd options may be added to init later. For example, command values
Other \fIcmd\fR options may be added to \fBinit\fR later. For example, command values
0, 5 and 7 are defined but currently not implemented.
The runlevel variable will specify the runlevel to switch to (0-6).
The \fIrunlevel\fR variable will specify the runlevel to switch to (0-6).
The sleeptime variable is to be used when we want to tell init to change
the time spent waiting between sending SIGTERM and SIGKILL during the
The \fIsleeptime\fR variable is to be used when we want to tell \fBinit\fR to change
the time spent waiting between sending \fBSIGTERM\fR and \fBSIGKILL\fR during the
shutdown process. Changing this at run time is not yet implemented.
The data variable (in the union) can be used to pass misc data which init
The \fIdata\fR variable (in the union) can be used to pass misc data which init
might need to process our request. For example, when setting environment
variables.
When setting an environment variable through init's /run/initctl pipe,
the data variable should have the format VARIABLE=VALUE. The string
When setting an environment variable through \fBinit\fR's \fI/run/initctl\fR pipe,
the data variable should have the format \fIVARIABLE\fR=\fIVALUE\fR. The string
should be terminated with a NULL character.
.SH EXAMPLES
The following C code example shows how to send a set environment variable
request to the init process using the /run/initctl pipe. This example
is simplified and skips the error checking. A more comlpete example can be
found in the shutdown.c program's init_setnv() function.
request to the \fBinit\fR process using the \fI/run/initctl\fR pipe. This example
is simplified and skips the error checking. A more complete example can be
found in the shutdown.c program's \fBinit_setnv\fR() function.
.nf
struct init_request request; /* structure defined above */
@@ -117,32 +117,36 @@ if ((fd = open(INIT_FIFO, O_WRONLY)) >= 0) /* open pipe for writing */
.sp
.SH NOTES
Usually the /run/initctl pipe would only be used by low-level programs to
request a power-related shutdown or change the runlevel, like telinit
would do. Most of the time there is no need to talk to init directly, but
this gives us an extenable approach so init can be taught how to learn
Usually the \fI/run/initctl\fR pipe would only be used by low-level programs to
request a power-related shutdown or change the runlevel, like \fBtelinit\fR
would do. Most of the time there is no need to talk to \fBinit\fR directly, but
this gives us an extendable approach so \fBinit\fR can be taught how to learn
more commands.
.PP
The commands passed through the /run/initctl pipe must be sent in a specific
The commands passed through the \fI/run/initctl\fR pipe must be sent in a specific
binary format and be of a specific length. Larger data structures or ones
not using the proper format will be ignored. Typically, only root has the
ability to write to the initctl pipe for security reasons.
.PP
The /run/initctl pipe can be closed by sending init (PID 1) the SIGUSR2
The \fI/run/initctl\fR pipe can be closed by sending init (PID 1) the \fBSIGUSR2\fR
signal. This closes the pipe and leaves it closed. This may be useful
for making sure init is not keeping any files open. However, when the
pipe is closed, init no longer receives signals, such as those sent by
shutdown or telinit. In other words if we close the pipe, init cannot
change its runlevel directly. The pipe may be re-opened by sending init (PID 1)
the SIGUSR1 signal.
for making sure \fBinit\fR is not keeping any files open. However, when the
pipe is closed, \fBinit\fR no longer receives signals, such as those sent by
\fBshutdown\fR(8) or \fBtelinit\fR(8). In other words if we close the pipe, \fBinit\fR cannot
change its runlevel directly. The pipe may be re-opened by sending \fBinit\fR (PID 1)
the \fBSIGUSR1\fR signal.
.PP
If the /run/initctl pipe is closed then it may still be possible to bring
down the system using the shutdown command's -n flag, but this is not
If the \fI/run/initctl\fR pipe is closed then it may still be possible to bring
down the system using the \fBshutdown\fR(8) command's \fB-n\fR flag, but this is not
always clean and not recommended.
.SH FILES
/run/initctl
/sbin/init
.SH AUTHOR
Jesse Smith <jsmith@resonatingmedia.com>
.MT jsmith@\:resonatingmedia\:.com
Jesse Smith
.ME
.SH "SEE ALSO"
init(8)
.BR init (8)