fcntl.2: srcfix: start new sentences on new lines; rewrap source lines

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2015-01-08 06:54:37 +01:00
parent a25d701d19
commit 12cfd6227c
1 changed files with 43 additions and 33 deletions

View File

@ -1300,19 +1300,25 @@ of buffer space currently used to store data produces the error
.BR F_GETPIPE_SZ " (\fIvoid\fP; since Linux 2.6.35)"
Return (as the function result) the capacity of the pipe referred to by
.IR fd .
.\"
.SS File Sealing
File seals limit the set of allowed operations on a given file. For each
seal that is set on a file, a specific set of operations will fail with
File seals limit the set of allowed operations on a given file.
For each seal that is set on a file,
a specific set of operations will fail with
.B EPERM
on this file from now on. The file is said to be sealed. The default set of
seals depends on the type of the underlying file and filesystem. Currently, only
shmem supports sealing. On other filesystems, all
on this file from now on.
The file is said to be sealed.
The default set of seals depends on the type of the underlying
file and filesystem.
Currently, only shmem supports sealing.
On other filesystems, all
.BR fcntl (2)
operations that operate on seals will return
.BR EINVAL .
Seals are a property of an inode. Thus, all open files on an inode share the
same set of seals. Furthermore, seals can never be removed, only added. If a
seal is set, it is guaranteed to be enforced immediately.
Seals are a property of an inode.
Thus, all open files on an inode share the same set of seals.
Furthermore, seals can never be removed, only added.
If a seal is set, it is guaranteed to be enforced immediately.
The following set of seals is available so far:
.RS
.TP
@ -1323,14 +1329,14 @@ with
.B F_ADD_SEALS
will fail with
.BR EPERM .
Therefore, this seal prevents any modifications to the set of seals itself. If
the initial set of seals of a file includes
Therefore, this seal prevents any modifications to the set of seals itself.
If the initial set of seals of a file includes
.BR F_SEAL_SEAL ,
then this effectively causes the set of seals to be constant and locked.
.TP
.BR F_SEAL_SHRINK
If this seal is set, the file in question cannot be reduced in size. This
affects
If this seal is set, the file in question cannot be reduced in size.
This affects
.BR open (2)
with the
.B O_TRUNC
@ -1338,12 +1344,12 @@ flag and
.BR ftruncate (2).
They will fail with
.B EPERM
if you try to shrink the file in question. Increasing the file size is still
possible.
if you try to shrink the file in question.
Increasing the file size is still possible.
.TP
.BR F_SEAL_GROW
If this seal is set, the size of the file in question cannot be increased. This
affects
If this seal is set, the size of the file in question cannot be increased.
This affects
.BR write (2)
if you write across size boundaries,
.BR ftruncate (2)
@ -1351,23 +1357,25 @@ and
.BR fallocate (2).
These calls will fail with
.B EPERM
if you use them to increase the file size or write beyond size boundaries. If
you keep the size or shrink it, those calls still work as expected.
if you use them to increase the file size or write beyond size boundaries.
If you keep the size or shrink it, those calls still work as expected.
.TP
.BR F_SEAL_WRITE
If this seal is set, you cannot modify data contents of the file. Note that
shrinking or growing the size of the file is still possible and allowed. Thus,
this seal is normally used in combination with one of the other seals. This seal
affects
If this seal is set, you cannot modify data contents of the file.
Note that shrinking or growing the size of the file is
still possible and allowed.
Thus, this seal is normally used in combination with one of the other seals.
This seal affects
.BR write (2)
and
.BR fallocate (2)
(only in combination with the
.B FALLOC_FL_PUNCH_HOLE
flag). Those calls will fail with
flag).
Those calls will fail with
.B EPERM
if this seal is set. Furthermore, trying to create new shared, writable
memory-mappings via
if this seal is set.
Furthermore, trying to create new shared, writable memory-mappings via
.BR mmap (2)
will also fail with
.BR EPERM .
@ -1379,8 +1387,9 @@ with
.B F_ADD_SEALS
will fail with
.B EBUSY
if any writable, shared mapping exists. You have to unmap
those before you can add this seal. Furthermore, if there are any asynchronous
if any writable, shared mapping exists.
You have to unmap those before you can add this seal.
Furthermore, if there are any asynchronous
I/O operations pending on the file, all outstanding writes will be discarded.
.RE
.TP
@ -1389,8 +1398,9 @@ Add the seals given in
.I arg
to the set of seals of the inode pointed to by the file-descriptor
.IR fd .
Seals cannot be removed again. Once this call succeeds, the seals are enforced
by the kernel immediately. If the current set of seals includes
Seals cannot be removed again.
Once this call succeeds, the seals are enforced by the kernel immediately.
If the current set of seals includes
.B F_SEAL_SEAL
then this call will be rejected with
.BR EPERM .
@ -1399,11 +1409,11 @@ Adding a seal that is already set is a no-op, in case
is not set already.
.TP
.BR F_GET_SEALS " (\fIvoid\fP; since Linux TBD)"
Return (as the function result) the current set of seals of the inode referred
to by
Return (as the function result) the current set of seals
of the inode referred to by
.IR fd .
If no seals are set, 0 is returned. If the file does not support sealing, -1 is
returned and
If no seals are set, 0 is returned.
If the file does not support sealing, -1 is returned and
.I errno
is set to
.BR EINVAL .