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freebsd-skq/share/man/man4/ksyms.4

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mdoc: consistently spell our email addresses <foo@FreeBSD.org> Reviewed by: ru
2010-05-19 08:57:53 +00:00
.\" Copyright (c) 2008-2009 Stacey Son <sson@FreeBSD.org>
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
multiple: Remove 3rd clause from BSD license where approved by the regents and renumber. This patch skips files in contrib/ and crypto/ Acked by: imp Discussed with: emaste
2014-03-14 03:07:51 +00:00
.\" 3. Neither the name of the University nor the names of its contributors
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.\" may be used to endorse or promote products derived from this software
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
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.\" $FreeBSD$
.\"
Rework and simplify the ksyms(4) implementation. - Store the symbol table contents in an anonymous swap-backed object. Have mmap(/dev/ksyms) map that object, and stop mapping the symbol table into the calling process in ksyms_open(). Previously we would cache a pointer to the pmap of the opening process, and mmap(/dev/ksyms) would create a mapping using the physical address found by a pmap lookup at the initial mapping address. However, this assumes that the cached pmap is valid, which may not be the case. [1] - Remove the ksyms ioctl interface. It appears to have been added to work around a limitation in libelf that no longer exists; see r321842. Moreover, the interface is difficult to support and isn't present in illumos. Since ksyms was added specifically to support lockstat(1), it is expected that this removal won't have any real impact. - Simplify ksyms_read() to avoid unnecessary copying. - Don't call the device handle destructor if we fail to capture a snapshot of the kernel's symbol table. devfs will do that for us. Reported by: Ilja van Sprundel <ivansprundel@ioactive.com> [1] Reviewed by: kib (previous revision) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11789
2017-08-03 00:38:13 +00:00
.Dd August 2, 2017
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Dt KSYMS 4
.Os
.Sh NAME
.Nm ksyms
.Nd kernel symbol table interface
.Sh SYNOPSIS
.Cd "device ksyms"
.Sh DESCRIPTION
The
.Pa /dev/ksyms
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
character device provides a read-only interface to a snapshot of the kernel
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
symbol table.
The in-kernel symbol manager is designed to be able to handle
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
many types of symbols tables, however, only
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Xr elf 5
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
symbol tables are supported by this device.
The ELF format image contains two
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
sections: a symbol table and a corresponding string table.
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Bl -tag -width indent -offset indent
.It Dv Symbol Table
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
The SYMTAB section contains the symbol table entries present in the current
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
running kernel, including the symbol table entries of any loaded modules.
The symbols are ordered by the kernel module load time starting with kernel file
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
symbols first, followed by the first loaded module's symbols and so on.
.It Dv String Table
The STRTAB section contains the symbol name strings from the kernel and any
loaded modules that the symbol table entries reference.
.El
.Pp
Fix a bunch of typos and spelling mistakes.
2010-07-31 12:14:28 +00:00
Elf formatted symbol table data read from the
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pa /dev/ksyms
file represents the state of the kernel at the time when the device is opened.
Since
.Pa /dev/ksyms
has no text or data, most of the fields are initialized to NULL.
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
The
.Nm
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
driver does not block the loading or unloading of modules into the kernel
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
while the
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pa /dev/ksyms
file is open but may contain stale data.
.Sh FILES
.Bl -tag -width /dev/ksymsX
.It Pa /dev/ksyms
.El
.Sh ERRORS
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
An
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Xr open 2
of
.Pa /dev/ksyms
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
will fail if:
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Bl -tag -width Er
.It Bq Er EBUSY
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
The device is already open.
A process must close
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pa /dev/ksyms
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
before it can be opened again.
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.It Bq Er ENOMEM
There is a resource shortage in the kernel.
.It Bq Er ENXIO
The driver was unsuccessful in creating a snapshot of the kernel symbol
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
table.
This may occur if the kernel was in the process of loading or
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
unloading a module.
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.El
.Sh SEE ALSO
.Xr nlist 3 ,
.Xr elf 5 ,
.Xr kldload 8
.Sh HISTORY
A
.Nm
device exists in many different operating systems.
This implementation is similar in function to the Solaris and NetBSD
.Nm
driver.
.Pp
The
.Nm
driver first appeared in
.Fx 8.0
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
to support
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Xr lockstat 1 .
mdoc: move CAVEATS, BUGS and SECURITY CONSIDERATIONS sections to the bottom of the manpages and order them consistently. GNU groff doesn't care about the ordering, and doesn't even mention CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put them. Found by: mdocml lint run Reviewed by: ru
2010-05-13 12:07:55 +00:00
.Sh AUTHORS
The
.Nm
driver was written by
use .Mt to mark up email addresses consistently (final part) PR: 191174 Submitted by: Franco Fichtner <franco at lastsummer.de>
2014-06-26 21:46:14 +00:00
.An Stacey Son Aq Mt sson@FreeBSD.org .
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Sh BUGS
Remove trailing whitespace per mdoc lint warning Disussed with: gavin No objection from: doc Approved by: joel MFC after: 3 days
2012-03-29 05:02:12 +00:00
Because files can be dynamically linked into the kernel at any time the symbol
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
information can vary.
When you open the
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pa /dev/ksyms
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
file, you have access to an ELF image which represents a snapshot of the state
of the kernel symbol information at that instant in time.
Keeping the device open does not block the loading or unloading of kernel
modules.
To get a new snapshot you must close and re-open the device.
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pp
A process is only allowed to open the
.Pa /dev/ksyms
Fix a bunch of "sentence not on new line" warnings from igor(1). MFC after: 1 month
2016-06-08 08:50:35 +00:00
file once at a time.
The process must close the
Add the ksyms(4) pseudo driver. The ksyms driver allows a process to get a quick snapshot of the kernel's symbol table including the symbols from any loaded modules (the symbols are all merged into one symbol table). Unlike like other implementations, this ksyms driver maps memory in the process memory space to store the snapshot at the time /dev/ksyms is opened. It also checks to see if the process has already a snapshot open and won't allow it to open /dev/ksyms it again until it closes first. This prevents kernel and process memory from being exhausted. Note that /dev/ksyms is used by the lockstat(1) command. Reviewed by: gallatin kib (freebsd-arch) Approved by: gnn (mentor)
2009-05-26 21:39:09 +00:00
.Pa /dev/ksyms
before it is allowed to open it again.
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