sysctl: Add a root pointer to ctl_table_set

Add a ctl_table_root pointer to ctl_table set so it is easy to
go from a ctl_table_set to a ctl_table_root.

Signed-off-by: Eric W. Biederman <ebiederm@xm

sysctl: Add a root pointer to ctl_table_set

Add a ctl_table_root pointer to ctl_table set so it is easy to
go from a ctl_table_set to a ctl_table_root.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry

Replace sysctl_head_next with first_entry and next_entry. These new
iterators operate at the level of sysctl table entries an

sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry

Replace sysctl_head_next with first_entry and next_entry. These new
iterators operate at the level of sysctl table entries and filter
out any sysctl tables that should not be shown.

Utilizing two specialized functions instead of a single function removes
conditionals for handling awkward special cases that only come up
at the beginning of iteration, making the iterators easier to read
and understand.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry.

Replace the helpers that proc_sys_lookup uses with helpers that work
in terms of an entire sysctl directory. This is worse f

sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry.

Replace the helpers that proc_sys_lookup uses with helpers that work
in terms of an entire sysctl directory. This is worse for sysctl_lock
hold times but it is much better for code clarity and the code cleanups
to come.

find_in_table is no longer needed so it is removed.

find_entry a general helper to find entries in a directory is added.

lookup_entry is a simple wrapper around find_entry that takes the
sysctl_lock increases the use count if an entry is found and drops
the sysctl_lock.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Normalize the root_table data structure.

Every other directory has a .child member and we look at the .child
for our entries. Do the same for the root_table.

Signed-off-by: Eric W. Biederm

sysctl: Normalize the root_table data structure.

Every other directory has a .child member and we look at the .child
for our entries. Do the same for the root_table.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Factor out insert_header and erase_header

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Factor out init_header from __register_sysctl_paths

Factor out a routing to initialize the sysctl_table_header.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Initial support for auto-unregistering sysctl tables.

Add nreg to ctl_table_header. When nreg drops to 0 the ctl_table_header
will be unregistered.

Factor out drop_sysctl_table from unregi

sysctl: Initial support for auto-unregistering sysctl tables.

Add nreg to ctl_table_header. When nreg drops to 0 the ctl_table_header
will be unregistered.

Factor out drop_sysctl_table from unregister_sysctl_table, and add
the logic for decrementing nreg.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: A more obvious version of grab_header.

Instead of relying on sysct_head_next(NULL) to magically
return the right header for the root directory instead
explicitly transform NULL into the root

sysctl: A more obvious version of grab_header.

Instead of relying on sysct_head_next(NULL) to magically
return the right header for the root directory instead
explicitly transform NULL into the root directories header.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Remove the now unused ctl_table parent field.

While useful at one time for selinux and the sysctl sanity
checks those users no longer use the parent field and we can
safely remove it.

Inspi

sysctl: Remove the now unused ctl_table parent field.

While useful at one time for selinux and the sysctl sanity
checks those users no longer use the parent field and we can
safely remove it.

Inspired-by: Lucian Adrian Grijincu <lucian.grijincu@gmil.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Improve the sysctl sanity checks

- Stop validating subdirectories now that we only register leaf tables

- Cleanup and improve the duplicate filename check.
* Run the duplicate filename ch

sysctl: Improve the sysctl sanity checks

- Stop validating subdirectories now that we only register leaf tables

- Cleanup and improve the duplicate filename check.
* Run the duplicate filename check under the sysctl_lock to guarantee
we never add duplicate names.
* Reduce the duplicate filename check to nearly O(M*N) where M is the
number of entries in tthe table we are registering and N is the
number of entries in the directory before we got there.

- Move the duplicate filename check into it's own function and call
it directtly from __register_sysctl_table

- Kill the config option as the sanity checks are now cheap enough
the config option is unnecessary. The original reason for the config
option was because we had a huge table used to verify the proc filename
to binary sysctl mapping. That table has now evolved into the binary_sysctl
translation layer and is no longer part of the sysctl_check code.

- Tighten up the permission checks. Guarnateeing that files only have read
or write permissions.

- Removed redudant check for parents having a procname as now everything has
a procname.

- Generalize the backtrace logic so that we print a backtrace from
any failure of __register_sysctl_table that was not caused by
a memmory allocation failure. The backtrace allows us to track
down who erroneously registered a sysctl table.

Bechmark before (CONFIG_SYSCTL_CHECK=y):
make-dummies 0 999 -> 12s
rmmod dummy -> 0.08s

Bechmark before (CONFIG_SYSCTL_CHECK=n):
make-dummies 0 999 -> 0.7s
rmmod dummy -> 0.06s
make-dummies 0 99999 -> 1m13s
rmmod dummy -> 0.38s

Benchmark after:
make-dummies 0 999 -> 0.65s
rmmod dummy -> 0.055s
make-dummies 0 9999 -> 1m10s
rmmod dummy -> 0.39s

The sysctl sanity checks now impose no measurable cost.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: register only tables of sysctl files

Split the registration of a complex ctl_table array which may have
arbitrary numbers of directories (->child != NULL) and tables of files
into a series o

sysctl: register only tables of sysctl files

Split the registration of a complex ctl_table array which may have
arbitrary numbers of directories (->child != NULL) and tables of files
into a series of simpler registrations that only register tables of files.

Graphically:

register('dir', { + file-a
+ file-b
+ subdir1
+ file-c
+ subdir2
+ file-d
+ file-e })

is transformed into:
wrapper->subheaders[0] = register('dir', {file1-a, file1-b})
wrapper->subheaders[1] = register('dir/subdir1', {file-c})
wrapper->subheaders[2] = register('dir/subdir2', {file-d, file-e})
return wrapper

This guarantees that __register_sysctl_table will only see a simple
ctl_table array with all entries having (->child == NULL).

Care was taken to pass the original simple ctl_table arrays to
__register_sysctl_table whenever possible.

This change is derived from a similar patch written
by Lucrian Grijincu.

Inspired-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Add ctl_table chains into cstring paths

For any component of table passed to __register_sysctl_paths
that actually serves as a path, add that to the cstring path
that is passed to __register

sysctl: Add ctl_table chains into cstring paths

For any component of table passed to __register_sysctl_paths
that actually serves as a path, add that to the cstring path
that is passed to __register_sysctl_table.

The result is that for most calls to __register_sysctl_paths
we only pass a table to __register_sysctl_table that contains
no child directories.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Add support for register sysctl tables with a normal cstring path.

Make __register_sysctl_table the core sysctl registration operation and
make it take a char * string as path.

Now that bin

sysctl: Add support for register sysctl tables with a normal cstring path.

Make __register_sysctl_table the core sysctl registration operation and
make it take a char * string as path.

Now that binary paths have been banished into the real of backwards
compatibility in kernel/binary_sysctl.c where they can be safely
ignored there is no longer a need to use struct ctl_path to represent
path names when registering ctl_tables.

Start the transition to using normal char * strings to represent
pathnames when registering sysctl tables. Normal strings are easier
to deal with both in the internal sysctl implementation and for
programmers registering sysctl tables.

__register_sysctl_paths is turned into a backwards compatibility wrapper
that converts a ctl_path array into a normal char * string.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Create local copies of directory names used in paths

Creating local copies of directory names is a good idea for
two reasons.
- The dynamic names used by callers must be copied into new
st

sysctl: Create local copies of directory names used in paths

Creating local copies of directory names is a good idea for
two reasons.
- The dynamic names used by callers must be copied into new
strings by the callers today to ensure the strings do not
change between register and unregister of the sysctl table.

- Sysctl directories have a potentially different lifetime
than the time between register and unregister of any
particular sysctl table.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Remove the unnecessary sysctl_set parent concept.

In sysctl_net register the two networking roots in the proper order.

In register_sysctl walk the sysctl sets in the reverse order of the
sy

sysctl: Remove the unnecessary sysctl_set parent concept.

In sysctl_net register the two networking roots in the proper order.

In register_sysctl walk the sysctl sets in the reverse order of the
sysctl roots.

Remove parent from ctl_table_set and setup_sysctl_set as it is no
longer needed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Implement retire_sysctl_set

This adds a small helper retire_sysctl_set to remove the intimate knowledge about
the how a sysctl_set is implemented from net/sysct_net.c

Signed-off-by: Eric W.

sysctl: Implement retire_sysctl_set

This adds a small helper retire_sysctl_set to remove the intimate knowledge about
the how a sysctl_set is implemented from net/sysct_net.c

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Make the directories have nlink == 1

I goofed when I made sysctl directories have nlink == 0.
nlink == 0 means the directory has been deleted.
nlink == 1 meands a directory does not count su

sysctl: Make the directories have nlink == 1

I goofed when I made sysctl directories have nlink == 0.
nlink == 0 means the directory has been deleted.
nlink == 1 meands a directory does not count subdirectories.

Use the default nlink == 1 for sysctl directories.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Move the implementation into fs/proc/proc_sysctl.c

Move the core sysctl code from kernel/sysctl.c and kernel/sysctl_check.c
into fs/proc/proc_sysctl.c.

Currently sysctl maintenance is hampe

sysctl: Move the implementation into fs/proc/proc_sysctl.c

Move the core sysctl code from kernel/sysctl.c and kernel/sysctl_check.c
into fs/proc/proc_sysctl.c.

Currently sysctl maintenance is hampered by the sysctl implementation
being split across 3 files with artificial layering between them.
Consolidate the entire sysctl implementation into 1 file so that
it is easier to see what is going on and hopefully allowing for
simpler maintenance.

For functions that are now only used in fs/proc/proc_sysctl.c remove
their declarations from sysctl.h and make them static in fs/proc/proc_sysctl.c

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: Register the base sysctl table like any other sysctl table.

Simplify the code by treating the base sysctl table like any other
sysctl table and register it with register_sysctl_table.

To en

sysctl: Register the base sysctl table like any other sysctl table.

Simplify the code by treating the base sysctl table like any other
sysctl table and register it with register_sysctl_table.

To ensure this table is registered early enough to avoid problems
call sysctl_init from proc_sys_init.

Rename sysctl_net.c:sysctl_init() to net_sysctl_init() to avoid
name conflicts now that kernel/sysctl.c:sysctl_init() is no longer
static.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: remove impossible condition check

Remove checks for conditions that will never happen. If procname is NULL
the loop would already had bailed out, so there's no need to check it
again.

At th

sysctl: remove impossible condition check

Remove checks for conditions that will never happen. If procname is NULL
the loop would already had bailed out, so there's no need to check it
again.

At the same time this also compacts the function find_in_table() by
refactoring it to be easier to read.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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sysctl: add support for poll()

Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs

sysctl: add support for poll()

Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.

[akpm@linux-foundation.org: s/declare/define/ for definitions]
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Greg KH <gregkh@suse.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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procfs: report EISDIR when reading sysctl dirs in proc

On reading sysctl dirs we should return -EISDIR instead of -EINVAL.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Cyrill Go

procfs: report EISDIR when reading sysctl dirs in proc

On reading sysctl dirs we should return -EISDIR instead of -EINVAL.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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filesystems: add missing nlink wrappers

Replace direct i_nlink updates with the respective updater function
(inc_nlink, drop_nlink, clear_nlink, inode_dec_link_count).

Signed-off-by: Miklos Szeredi

filesystems: add missing nlink wrappers

Replace direct i_nlink updates with the respective updater function
(inc_nlink, drop_nlink, clear_nlink, inode_dec_link_count).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

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->permission() sanitizing: don't pass flags to ->permission()

not used by the instances anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

->permission() sanitizing: MAY_NOT_BLOCK

Duplicate the flags argument into mask bitmap.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>