archive_read_disk - archive_read_disk_new, archive_read_disk_open, archive_read_disk_open_w, archive_read_disk_set_behavior, archive_read_disk_set_symlink_logical, archive_read_disk_set_symlink_physical, archive_read_disk_set_symlink_hybrid, archive_read_disk_entry_from_file, archive_read_disk_gname, archive_read_disk_uname, archive_read_disk_set_uname_lookup, archive_read_disk_set_gname_lookup, archive_read_disk_set_standard_lookup, archive_read_disk_descend, archive_read_disk_can_descend, archive_read_disk_current_filesystem, archive_read_disk_current_filesystem_is_synthetic, archive_read_disk_current_filesystem_is_remote, archive_read_disk_set_matching, functions for reading objects from disk
#include <archive.h> struct archive * archive_read_disk_new(void); int archive_read_disk_open(struct archive *, const char *); int archive_read_disk_open_w(struct archive *, const wchar_t *, ); int archive_read_disk_set_behavior(struct archive *, int); int archive_read_disk_set_symlink_logical(struct archive *); int archive_read_disk_set_symlink_physical(struct archive *); int archive_read_disk_set_symlink_hybrid(struct archive *); const char * archive_read_disk_gname(struct archive *, gid_t); const char * archive_read_disk_uname(struct archive *, uid_t); int archive_read_disk_set_gname_lookup(struct archive *, void *, const char *(*lookup)(void *, gid_t), void (*cleanup)(void *)); int archive_read_disk_set_uname_lookup(struct archive *, void *, const char *(*lookup)(void *, uid_t), void (*cleanup)(void *)); int archive_read_disk_set_standard_lookup(struct archive *); int archive_read_disk_entry_from_file(struct archive *, struct archive_entry *, int fd, const struct stat *); int archive_read_disk_descend(struct archive *); int archive_read_disk_can_descend(struct archive *); int archive_read_disk_current_filesystem(struct archive *); int archive_read_disk_current_filesystem_is_synthetic(struct archive *); int archive_read_disk_current_filesystem_is_remote(struct archive *); int archive_read_disk_set_matching(struct archive *, struct archive *, void (*excluded_func)(struct archive *, void *, struct archive entry *), void *); int archive_read_disk_set_metadata_filter_callback(struct archive *, int (*metadata_filter_func)(struct archive *, void*, struct archive_entry *), void *);
ARCHIVE_READ_DISK(3archive)
NAME
archive_read_disk_new, archive_read_disk_open,
archive_read_disk_open_w, archive_read_disk_set_behavior,
archive_read_disk_set_symlink_logical,
archive_read_disk_set_symlink_physical,
archive_read_disk_set_symlink_hybrid,
archive_read_disk_entry_from_file, archive_read_disk_gname,
archive_read_disk_uname, archive_read_disk_set_uname_lookup,
archive_read_disk_set_gname_lookup,
archive_read_disk_set_standard_lookup, archive_read_disk_descend,
archive_read_disk_can_descend, archive_read_disk_current_filesystem,
archive_read_disk_current_filesystem_is_synthetic,
archive_read_disk_current_filesystem_is_remote,
archive_read_disk_set_matching,
archive_read_disk_set_metadata_filter_callback, - functions for reading
objects from disk
LIBRARY
Streaming Archive Library (libarchive, -larchive)
SYNOPSIS
#include <archive.h>
struct archive *
archive_read_disk_new(void);
int
archive_read_disk_open(struct archive *, const char *);
int
archive_read_disk_open_w(struct archive *, const wchar_t *, );
int
archive_read_disk_set_behavior(struct archive *, int);
int
archive_read_disk_set_symlink_logical(struct archive *);
int
archive_read_disk_set_symlink_physical(struct archive *);
int
archive_read_disk_set_symlink_hybrid(struct archive *);
const char *
archive_read_disk_gname(struct archive *, gid_t);
const char *
archive_read_disk_uname(struct archive *, uid_t);
int
archive_read_disk_set_gname_lookup(struct archive *, void *,
const char *(*lookup)(void *, gid_t), void (*cleanup)(void *));
int
archive_read_disk_set_uname_lookup(struct archive *, void *,
const char *(*lookup)(void *, uid_t), void (*cleanup)(void *));
int
archive_read_disk_set_standard_lookup(struct archive *);
int
archive_read_disk_entry_from_file(struct archive *,
struct archive_entry *, int fd, const struct stat *);
int
archive_read_disk_descend(struct archive *);
int
archive_read_disk_can_descend(struct archive *);
int
archive_read_disk_current_filesystem(struct archive *);
int
archive_read_disk_current_filesystem_is_synthetic(struct archive *);
int
archive_read_disk_current_filesystem_is_remote(struct archive *);
int
archive_read_disk_set_matching(struct archive *, struct archive *,
void (*excluded_func)(struct archive *, void *, struct archive entry *),
void *);
int
archive_read_disk_set_metadata_filter_callback(struct archive *,
int (*metadata_filter_func)(struct archive *, void*, struct archive_entry *),
void *);
DESCRIPTION
These functions provide an API for reading information about objects on
disk. In particular, they provide an interface for populating Tn
struct archive_entry objects.
archive_read_disk_new()
Allocates and initializes a Tn struct archive object suit-
able for reading object information from disk.
archive_read_disk_open()
Opens the file or directory from the given path and pre-
pares the Tn struct archive to read it from disk.
archive_read_disk_open_w()
Opens the file or directory from the given path as a wide
character string and prepares the Tn struct archive to read
it from disk.
archive_read_disk_set_behavior()
Configures various behavior options when reading entries
from disk. The flags field consists of a bitwise OR of one
or more of the following values:
ARCHIVE_READDISK_HONOR_NODUMP
Skip files and directories with the nodump file
attribute (file flag) set. By default, the nodump
file attribute is ignored.
ARCHIVE_READDISK_MAC_COPYFILE
Mac OS X specific. Read metadata (ACLs and extended
attributes) with copyfile(3). By default, metadata is
read using copyfile(3).
ARCHIVE_READDISK_NO_ACL
Do not read Access Control Lists. By default, ACLs
are read from disk.
ARCHIVE_READDISK_NO_FFLAGS
Do not read file attributes (file flags). By default,
file attributes are read from disk. See chattr(1)
(Linux) or chflags(1) (FreeBSD, Mac OS X) for more
information on file attributes.
ARCHIVE_READDISK_NO_TRAVERSE_MOUNTS
Do not traverse mount points. By default, mount
points are traversed.
ARCHIVE_READDISK_NO_XATTR
Do not read extended file attributes (xattrs). By
default, extended file attributes are read from disk.
See xattr(7) (Linux,) xattr(2) (Mac OS X,) or getex-
tattr(8) (FreeBSD) for more information on extended
file attributes.
ARCHIVE_READDISK_RESTORE_ATIME
Restore access time of traversed files. By default,
access time of traversed files is not restored.
ARCHIVE_READDISK_NO_SPARSE
Do not read sparse file information. By default,
sparse file information is read from disk.
archive_read_disk_set_symlink_logical(),
archive_read_disk_set_symlink_physical(),
archive_read_disk_set_symlink_hybrid() This sets the mode
used for handling symbolic links. The ``logical'' mode
follows all symbolic links. The ``physical'' mode does not
follow any symbolic links. The ``hybrid'' mode currently
behaves identically to the ``logical'' mode.
archive_read_disk_gname(),
archive_read_disk_uname() Returns a user or group name
given a gid or uid value. By default, these always return
a NULL string.
archive_read_disk_set_gname_lookup(),
archive_read_disk_set_uname_lookup() These allow you to
override the functions used for user and group name
lookups. You may also provide a Tn void * pointer to a
private data structure and a cleanup function for that
data. The cleanup function will be invoked when the Tn
struct archive object is destroyed or when new lookup func-
tions are registered.
archive_read_disk_set_standard_lookup()
This convenience function installs a standard set of user
and group name lookup functions. These functions use getp-
wuid(3) and getgrgid(3) to convert ids to names, defaulting
to NULL if the names cannot be looked up. These functions
also implement a simple memory cache to reduce the number
of calls to getpwuid(3) and getgrgid(3).
archive_read_disk_entry_from_file()
Populates a Tn struct archive_entry object with information
about a particular file. The Tn archive_entry object must
have already been created with archive_entry_new(3) and at
least one of the source path or path fields must already be
set. (If both are set, the source path will be used.)
Information is read from disk using the path name from the Tn
struct archive_entry object. If a file descriptor is provided,
some information will be obtained using that file descriptor, on
platforms that support the appropriate system calls.
If a pointer to a Tn struct stat is provided, information from
that structure will be used instead of reading from the disk where
appropriate. This can provide performance benefits in scenarios
where Tn struct stat information has already been read from the
disk as a side effect of some other operation. (For example,
directory traversal libraries often provide this information.)
Where necessary, user and group ids are converted to user and
group names using the currently-registered lookup functions above.
This affects the file ownership fields and ACL values in the Tn
struct archive_entry object.
archive_read_disk_descend()
If the current entry can be descended, this function will
mark the directory as the next entry for ar-
chive_read_header(3) to visit.
archive_read_disk_can_descend()
Returns 1 if the current entry is an unvisited directory
and 0 otherwise.
archive_read_disk_current_filesystem()
Returns the index of the most recent filesystem entry that
has been visited through archive_read_disk
archive_read_disk_current_filesystem_is_synthetic()
Returns 1 if the current filesystem is a virtual filesys-
tem. Returns 0 if the current filesystem is not a virtual
filesystem. Returns -1 if it is unknown.
archive_read_disk_current_filesystem_is_remote()
Returns 1 if the current filesystem is a remote filesystem.
Returns 0 if the current filesystem is not a remote
filesystem. Returns -1 if it is unknown.
archive_read_disk_set_matching()
Allows the caller to set Tn struct archive *_ma to compare
each entry during archive_read_header(3) calls. If matched
based on calls to Tn archive_match_path_excluded, Tn ar-
chive_match_time_excluded, or Tn ar-
chive_match_owner_excluded, then the callback function
specified by the _excluded_func parameter will execute.
This function will recieve data provided to the fourth
parameter, void *_client_data.
archive_read_disk_set_metadata_filter_callback()
Allows the caller to set a callback function during calls
to archive_read_header(3) to filter out metadata for each
entry. The callback function recieves the Tn struct archive
object, void* custom filter data, and the Tn struct ar-
chive_entry. If the callback function returns an error,
ARCHIVE_RETRY will be returned and the entry will not be
further processed.
More information about the struct archive object and the overall design
of the library can be found in the libarchive(3) overview.
EXAMPLES
The following illustrates basic usage of the library by showing how to
use it to copy an item on disk into an archive.
void
file_to_archive(struct archive *a, const char *name)
{
char buff[8192];
size_t bytes_read;
struct archive *ard;
struct archive_entry *entry;
int fd;
ard = archive_read_disk_new();
archive_read_disk_set_standard_lookup(ard);
entry = archive_entry_new();
fd = open(name, O_RDONLY);
if (fd < 0)
return;
archive_entry_copy_pathname(entry, name);
archive_read_disk_entry_from_file(ard, entry, fd, NULL);
archive_write_header(a, entry);
while ((bytes_read = read(fd, buff, sizeof(buff))) > 0)
archive_write_data(a, buff, bytes_read);
archive_write_finish_entry(a);
archive_read_free(ard);
archive_entry_free(entry);
}
RETURN VALUES
Most functions return ARCHIVE_OK (zero) on success, or one of several
negative error codes for errors. Specific error codes include: AR-
CHIVE_RETRY for operations that might succeed if retried, ARCHIVE_WARN
for unusual conditions that do not prevent further operations, and AR-
CHIVE_FATAL for serious errors that make remaining operations impossi-
ble.
archive_read_disk_new() returns a pointer to a newly-allocated Tn
struct archive object or NULL if the allocation failed for any reason.
archive_read_disk_gname() and archive_read_disk_uname() return Tn const
char * pointers to the textual name or NULL if the lookup failed for
any reason. The returned pointer points to internal storage that may
be reused on the next call to either of these functions; callers should
copy the string if they need to continue accessing it.
ERRORS
Detailed error codes and textual descriptions are available from the
archive_errno() and archive_error_string() functions.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+--------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------+
|Availability | library/libarchive |
+---------------+--------------------+
|Stability | Uncommitted |
+---------------+--------------------+
SEE ALSO
tar(1), archive_read(3), archive_util(3), archive_write(3), ar-
chive_write_disk(3), libarchive(3)
HISTORY
The libarchive library first appeared in FreeBSD 5.3. The
archive_read_disk interface was added to libarchive 2.6 and first
appeared in FreeBSD 8.0.
AUTHORS
-nosplit The libarchive library was written by Tim Kientzle
<kientzle@FreeBSD.org.>
BUGS
The ``standard'' user name and group name lookup functions are not the
defaults because getgrgid(3) and getpwuid(3) are sometimes too large
for particular applications. The current design allows the application
author to use a more compact implementation when appropriate.
The full list of metadata read from disk by
archive_read_disk_entry_from_file() is necessarily system-dependent.
The archive_read_disk_entry_from_file() function reads as much informa-
tion as it can from disk. Some method should be provided to limit this
so that clients who do not need ACLs, for instance, can avoid the extra
work needed to look up such information.
This API should provide a set of methods for walking a directory tree.
That would make it a direct parallel of the archive_read(3) API. When
such methods are implemented, the ``hybrid'' symbolic link mode will
make sense.
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://github.com/libarchive/libarchive/releases/down-
load/v3.6.1/libarchive-3.6.1.tar.gz.
Further information about this software can be found on the open source
community website at http://www.libarchive.org/.
April 3, 2017
ARCHIVE_READ_DISK(3archive)