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Part III: Update extended attribute system call interface documentation.

Browse Source 
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
This commit is contained in:
Robert Watson 2002-02-10 04:46:28 +00:00
parent 1aa1d02a98
commit c0858e0a77
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=90450
1 changed files with 39 additions and 18 deletions
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57
lib/libc/sys/extattr_get_file.2
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@ -42,16 +42,16 @@
.In sys/types.h
.In sys/extattr.h
.In sys/uio.h
.Ft ssize_t
.Fn extattr_get_fd "int fd" "int attrnamespace" "const char *attrname" "void *data" "size_t nbytes"
.Ft int
.Fn extattr_get_fd "int fd" "int attrnamespace" "const char *attrname" "struct iovec *iovp" "unsigned iovcnt"
.Ft int
.Fn extattr_set_fd "int fd" "int attrnamespace" "const char *attrname" "struct iovec *iovp" "unsigned iovcnt"
.Fn extattr_set_fd "int fd" "int attrnamespace" "const char *attrname" "const void *data" "size_t nbytes"
.Ft int
.Fn extattr_delete_fd "int fd" "int attrnamespace" "const char *attrname"
.Ft ssize_t
.Fn extattr_get_file "const char *path" "int attrnamespace" "const char *attrname" "void *data" "size_t nbytes"
.Ft int
.Fn extattr_get_file "const char *path" "int attrnamespace" "const char *attrname" "struct iovec *iovp" "unsigned iovcnt"
.Ft int
.Fn extattr_set_file "const char *path" "int attrnamespace" "const char *attrname" "struct iovec *iovp" "unsigned iovcnt"
.Fn extattr_set_file "const char *path" "int attrnamespace" "const char *attrname" "const void *data" "size_t nbytes"
.Ft int
.Fn extattr_delete_file "const char *path" "int attrnamespace" "const char *attrname"
.Sh DESCRIPTION
@ -63,12 +63,16 @@ pairs within a set of namespaces.
The
.Fn extattr_get_file
call retrieves the value of the specified extended attribute into
.Fa iovp .
a buffer pointed to by
.Fa data
of size
.Fa nbytes
.
The
.Fn extattr_set_file
call sets the value of the specified extended attribute to the data
described by
.Fa iovp .
.Fa data .
The
.Fn extattr_delete_file
call deletes the extended attribute specified.
@ -77,14 +81,23 @@ The
and
.Fn extattr_set_file
calls consume the
.Fa iovp
.Fa data
and
.Fa iovcnt
.Fa nbytes
arguments in the style of
.Xr readv 2
.Xr read 2
and
.Xr writev 2 ,
.Xr write 2 ,
respectively.
If
.Fa data
is
.Dv NULL
in a call to
.Fn extattr_get_file
then the size of defined extended attribute data will be returned, rather
than the quantity read, permitting applications to test the size of the
data without performing a read.
.Pp
The
.Fn extatttr_get_fd ,
@ -114,7 +127,7 @@ the name of the extended attribute
Named extended attribute semantics vary by filesystem implementing the call.
Not all operations may be supported for a particular attribute.
Additionally, the format of the data in
.Fa iovp
.Fa data
is attribute-specific.
.Pp
For more information on named extended attributes, please see
@ -130,8 +143,14 @@ and
.Fn extattr_set_file
calls return the number of bytes
that were read or written from the
.Fa iovp ,
respectively.
.Fa data ,
respectively, or if
.Fa data
was
.Dv NULL ,
then
.Fn extattr_get_file
returns the number of bytes available to read.
If any of the calls are unsuccessful, the value \-1 is returned
and the global variable
.Va errno
@ -146,9 +165,11 @@ other errors it desires.
.It Bq Er EFAULT
.Fa attrnamespace ,
.Fa attrname ,
or
.Fa iovp
point outside the process's allocated address space.
or the memory range defined by
.Fa data
and
.Fa nbytes
points outside the process's allocated address space.
.It Bq Er ENAMETOOLONG
The attribute name was longer than
.Dv EXTATTR_MAXNAMELEN .