freebsd-skq/lib/libarchive/archive_entry.3
Tim Kientzle 61fac2242c Update file flag handling.
The new fflags support in archive_entry supports Linux and FreeBSD
file flags and is a bit more gracious about unrecognized flag names
than strtofflags(3).  This involves some minor API breakage.

The default tar format ("restricted pax") now enables pax extensions
when archiving files that have flags.  In particular, copying dir
heirarchies with 'bsdtar cf - -C src . | bsdtar xpf - -C dest' now
preserves file flags.  (Note the "p" on extract!)

While I'm here, fill in some additional explanation in the
archive_entry.3 manpage, fill in some missing MLINKS, mark some
overlooked internal functions 'static', and make a few minor style
fixes.
2004-04-26 23:37:54 +00:00

286 lines
10 KiB
Groff

.\" Copyright (c) 2003-2004 Tim Kientzle
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" 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
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.\" documentation and/or other materials provided with the distribution.
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" $FreeBSD$
.\"
.Dd December 15, 2003
.Dt archive_entry 3
.Os
.Sh NAME
.Nm archive_entry_clear
.Nm archive_entry_clone
.Nm archive_entry_copy_fflags_text_w
.Nm archive_entry_copy_gname_w
.Nm archive_entry_copy_hardlink_w
.Nm archive_entry_copy_pathname_w
.Nm archive_entry_copy_stat
.Nm archive_entry_copy_symlink_w
.Nm archive_entry_copy_uname_w
.Nm archive_entry_fflags
.Nm archive_entry_fflags_text
.Nm archive_entry_free
.Nm archive_entry_gname
.Nm archive_entry_gname_w
.Nm archive_entry_hardlink
.Nm archive_entry_hardlink_w
.Nm archive_entry_new
.Nm archive_entry_pathname
.Nm archive_entry_pathname_w
.Nm archive_entry_set_devmajor
.Nm archive_entry_set_devminor
.Nm archive_entry_set_fflags
.Nm archive_entry_set_gid
.Nm archive_entry_set_gname
.Nm archive_entry_set_hardlink
.Nm archive_entry_set_link
.Nm archive_entry_set_mode
.Nm archive_entry_set_pathname
.Nm archive_entry_set_symlink
.Nm archive_entry_set_uid
.Nm archive_entry_set_uname
.Nm archive_entry_size
.Nm archive_entry_stat
.Nm archive_entry_symlink
.Nm archive_entry_symlink_w
.Nm archive_entry_uname
.Nm archive_entry_uname_w
.Nd functions for manipulating archive entry descriptions
.Sh SYNOPSIS
.In archive_entry.h
.Ft void
.Fn archive_entry_clear "struct archive_entry *"
.Ft struct archive_entry *
.Fn archive_entry_clone "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_copy_fflags_text_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_copy_gname_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_copy_hardlink_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_copy_pathname_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_copy_stat "struct archive_entry *" "struct stat *"
.Ft void
.Fn archive_entry_copy_symlink_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_copy_uname_w "struct archive_entry *" "const wchar_t *"
.Ft void
.Fn archive_entry_fflags "struct archive_entry *" "unsigned long *set" "unsigned long *clear"
.Ft const char *
.Fn archive_entry_fflags_text "struct archive_entry *"
.Ft void
.Fn archive_entry_free "struct archive_entry *"
.Ft const char *
.Fn archive_entry_gname "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_gname_w "struct archive_entry *"
.Ft const char *
.Fn archive_entry_hardlink "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_hardlink_w "struct archive_entry *"
.Ft struct archive_entry *
.Fn archive_entry_new "void"
.Ft const char *
.Fn archive_entry_pathname "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_pathname_w "struct archive_entry *"
.Ft void
.Fn archive_entry_set_devmajor "struct archive_entry *" "dev_t"
.Ft void
.Fn archive_entry_set_devminor "struct archive_entry *" "dev_t"
.Ft void
.Fn archive_entry_set_fflags "struct archive_entry *" "unsigned long set" "unsigned long clear"
.Ft void
.Fn archive_entry_set_gid "struct archive_entry *" "gid_t"
.Ft void
.Fn archive_entry_set_gname "struct archive_entry *" "const char *"
.Ft void
.Fn archive_entry_set_hardlink "struct archive_entry *" "const char *"
.Ft void
.Fn archive_entry_set_mode "struct archive_entry *" "mode_t"
.Ft void
.Fn archive_entry_set_pathname "struct archive_entry *" "const char *"
.Ft void
.Fn archive_entry_set_symlink "struct archive_entry *" "const char *"
.Ft void
.Fn archive_entry_set_uid "struct archive_entry *" "uid_t"
.Ft void
.Fn archive_entry_set_uname "struct archive_entry *" "const char *"
.Ft int64_t
.Fn archive_entry_size "struct archive_entry *"
.Ft const struct stat *
.Fn archive_entry_stat "struct archive_entry *"
.Ft const char *
.Fn archive_entry_symlink "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_symlink_w "struct archive_entry *"
.Ft const char *
.Fn archive_entry_uname "struct archive_entry *"
.Ft const wchar_t *
.Fn archive_entry_uname_w "struct archive_entry *"
.Sh DESCRIPTION
These functions create and manipulate data objects that
represent entries within an archive.
You can think of a
.Tn struct archive_entry
as a heavy-duty version of
.Tn struct stat :
it includes everything from
.Tn struct stat
plus associated pathname, textual group and user names, etc.
These objects are used by
.Xr libarchive 3
to represent the metadata associated with a particular
entry in an archive.
.Ss Create and Destroy
There are functions to allocate, destroy, clear, and copy
.Va archive_entry
objects:
.Bl -tag -compact -width indent
.It Fn archive_entry_clear
Erases the object, resetting all internal fields to the
same state as a newly-created object.
This is provided to allow you to quickly recycle objects
without thrashing the heap.
.It Fn archive_entry_clone
A deep copy operation; all text fields are duplicated.
.It Fn archive_entry_free
Releases the
.Tn struct archive_entry
object.
.It Fn archive_entry_new
Allocate and return a blank
.Tn struct archive_entry
object.
.El
.Ss Set and Get Functions
Most of the functions here set or read entries in an object.
Such functions have one of the following forms:
.Bl -tag -compact -width indent
.It Fn archive_entry_set_XXXX
Stores the provided data in the object.
In particular, for strings, the pointer is stored,
not the referenced string.
.It Fn archive_entry_copy_XXXX
As above, except that the referenced data is copied
into the object.
.It Fn archive_entry_XXXX
Returns the specified data.
In the case of strings, a const-qualified pointer to
the string is returned.
.El
String data can be set or accessed as wide character strings
or normal
.Va char
strings.
The funtions that use wide character strings are suffixed with
.Cm _w .
Note that these are different representations of the same data:
For example, if you store a narrow string and read the corresponding
wide string, the object will transparently convert formats
using the current locale.
Similarly, if you store a wide string and then store a
narrow string for the same data, the previously-set wide string will
be discarded in favor of the new data.
.Pp
There are a few set/get functions that merit additional description:
.Bl -tag -compact -width indent
.It Fn archive_entry_set_link
This function sets the symlink field if it is already set.
Otherwise, it sets the hardlink field.
.El
.Ss File Flags
File flags are transparently converted between a bitmap
representation and a textual format.
For example, if you set the bitmap and ask for text, the library
will build a canonical text format.
However, if you set a text format and request a text format,
you will get back the same text, even if it is ill-formed.
If you need to canonicalize a textual flags string, you should first set the
text form, then request the bitmap form, then use that to set the bitmap form.
Setting the bitmap format will clear the internal text representation
and force it to be reconstructed when you next request the text form.
.Pp
The bitmap format consists of two integers, one containing bits
that should be set, the other specifying bits that should be
cleared.
Bits not mentioned in either bitmap will be ignored.
Usually, the bitmap of bits to be cleared will be set to zero.
In unusual circumstances, you can force a fully-specified set
of file flags by setting the bitmap of flags to clear to the complement
of the bitmap of flags to set.
(This differs from
.Xr fflagstostr 3 ,
which only includes names for set bits.)
Converting a bitmap to a textual string is a platform-specific
operation; bits that are not meaningful on the current platform
will be ignored.
.Pp
The canonical text format is a comma-separated list of flag names.
The
.Fn archive_entry_copy_fflags_text_w
function parses the provided text and sets the internal bitmap values.
This is a platform-specific operation; names that are not meaningful
on the current platform will be ignored.
The function returns a pointer to the start of the first name that was not
recognized, or NULL if every name was recognized.
Note that every name--including names that follow an unrecognized name--will
be evaluated, and the bitmaps will be set to reflect every name that is
recognized.
(In particular, this differs from
.Xr strtofflags 3 ,
which stops parsing at the first unrecognized name.)
.Ss ACL Handling
XXX This needs serious help. XXX
.Pp
An
.Dq Access Control List
(ACL) is a list of permissions that grant access to particular users or
groups beyond what would normally be provided by standard POSIX mode bits.
The ACL handling here addresses some deficiencies in the POSIX.1e draft 17 ACL
specification.
In particular, POSIX.1e draft 17 specifies several different formats, but
none of those formats include both textual user/group names and numeric
UIDs/GIDs.
.Pp
XXX explain ACL stuff XXX
.\" .Sh EXAMPLE
.\" .Sh RETURN VALUES
.\" .Sh ERRORS
.Sh SEE ALSO
.Xr archive 3
.Sh HISTORY
The
.Nm libarchive
library first appeared in
.Fx 5.3 .
.Sh AUTHORS
.An -nosplit
The
.Nm libarchive
library was written by
.An Tim Kientzle Aq kientzle@acm.org .
.\" .Sh BUGS