Blame doc/html/archive_write.3.html

Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
"http://www.w3.org/TR/html4/loose.dtd">
Packit 08bd4c
<html>
Packit 08bd4c
<head>
Packit 08bd4c
<meta name="generator" content="groff -Thtml, see www.gnu.org">
Packit 08bd4c
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
Packit 08bd4c
<meta name="Content-Style" content="text/css">
Packit 08bd4c
<style type="text/css">
Packit 08bd4c
       p       { margin-top: 0; margin-bottom: 0; vertical-align: top }
Packit 08bd4c
       pre     { margin-top: 0; margin-bottom: 0; vertical-align: top }
Packit 08bd4c
       table   { margin-top: 0; margin-bottom: 0; vertical-align: top }
Packit 08bd4c
       h1      { text-align: center }
Packit 08bd4c
</style>
Packit 08bd4c
<title></title>
Packit 08bd4c
</head>
Packit 08bd4c
<body>
Packit 08bd4c
Packit 08bd4c

Packit 08bd4c
Packit 08bd4c
Packit 08bd4c

ARCHIVE_WRITE(3) BSD Library Functions Manual

Packit 08bd4c
ARCHIVE_WRITE(3)

Packit 08bd4c
Packit 08bd4c

NAME

Packit 08bd4c
Packit 08bd4c

archive_write

Packit 08bd4c
functions for creating archives

Packit 08bd4c
Packit 08bd4c

LIBRARY

Packit 08bd4c
Packit 08bd4c

Streaming Archive Library

Packit 08bd4c
(libarchive, -larchive)

Packit 08bd4c
Packit 08bd4c

SYNOPSIS

Packit 08bd4c
Packit 08bd4c

#include

Packit 08bd4c
<archive.h>

Packit 08bd4c
Packit 08bd4c

DESCRIPTION

Packit 08bd4c
Packit 08bd4c

These functions provide a

Packit 08bd4c
complete API for creating streaming archive files. The
Packit 08bd4c
general process is to first create the struct archive
Packit 08bd4c
object, set any desired options, initialize the archive,
Packit 08bd4c
append entries, then close the archive and release all
Packit 08bd4c
resources.

Packit 08bd4c
Packit 08bd4c

Create

Packit 08bd4c
archive object 
Packit 08bd4c
See archive_write_new(3).

Packit 08bd4c
Packit 08bd4c

To write an

Packit 08bd4c
archive, you must first obtain an initialized struct archive
Packit 08bd4c
object from archive_write_new().

Packit 08bd4c
Packit 08bd4c

Enable

Packit 08bd4c
filters and formats, configure block size and padding
Packit 08bd4c

Packit 08bd4c
See archive_write_filter(3), archive_write_format(3) and
Packit 08bd4c
archive_write_blocksize(3).

Packit 08bd4c
Packit 08bd4c

You can then

Packit 08bd4c
modify this object for the desired operations with the
Packit 08bd4c
various archive_write_set_XXX() functions. In
Packit 08bd4c
particular, you will need to invoke appropriate
Packit 08bd4c
archive_write_add_XXX() and
Packit 08bd4c
archive_write_set_XXX() functions to enable the
Packit 08bd4c
corresponding compression and format support.

Packit 08bd4c
Packit 08bd4c

Set

Packit 08bd4c
options 
Packit 08bd4c
See archive_read_set_options(3).

Packit 08bd4c
Packit 08bd4c

Open

Packit 08bd4c
archive 
Packit 08bd4c
See archive_write_open(3).

Packit 08bd4c
Packit 08bd4c

Once you have

Packit 08bd4c
prepared the struct archive object, you call
Packit 08bd4c
archive_write_open() to actually open the archive and
Packit 08bd4c
prepare it for writing. There are several variants of this
Packit 08bd4c
function; the most basic expects you to provide pointers to
Packit 08bd4c
several functions that can provide blocks of bytes from the
Packit 08bd4c
archive. There are convenience forms that allow you to
Packit 08bd4c
specify a filename, file descriptor, FILE * object,
Packit 08bd4c
or a block of memory from which to write the archive
Packit 08bd4c
data.

Packit 08bd4c
Packit 08bd4c

Produce

Packit 08bd4c
archive 
Packit 08bd4c
See archive_write_header(3) and archive_write_data(3).

Packit 08bd4c
Packit 08bd4c

Individual

Packit 08bd4c
archive entries are written in a three-step process: You
Packit 08bd4c
first initialize a struct archive_entry structure with
Packit 08bd4c
information about the new entry. At a minimum, you should
Packit 08bd4c
set the pathname of the entry and provide a struct
Packit 08bd4c
stat with a valid st_mode field, which specifies
Packit 08bd4c
the type of object and st_size field, which specifies
Packit 08bd4c
the size of the data portion of the object.

Packit 08bd4c
Packit 08bd4c

Release

Packit 08bd4c
resources 
Packit 08bd4c
See archive_write_free(3).

Packit 08bd4c
Packit 08bd4c

After all

Packit 08bd4c
entries have been written, use the
Packit 08bd4c
archive_write_free() function to release all
Packit 08bd4c
resources.

Packit 08bd4c
Packit 08bd4c

EXAMPLE

Packit 08bd4c
Packit 08bd4c

The following sketch illustrates

Packit 08bd4c
basic usage of the library. In this example, the callback
Packit 08bd4c
functions are simply wrappers around the standard open(2),
Packit 08bd4c
write(2), and close(2) system calls.

Packit 08bd4c
Packit 08bd4c

#ifdef

Packit 08bd4c
__linux__

Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
       cellspacing="0" cellpadding="0">
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c

#define

Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c

_FILE_OFFSET_BITS 64

Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c
Packit 08bd4c

#endif

Packit 08bd4c
#include <sys/stat.h> 
Packit 08bd4c
#include <archive.h> 
Packit 08bd4c
#include <archive_entry.h> 
Packit 08bd4c
#include <fcntl.h> 
Packit 08bd4c
#include <stdlib.h> 
Packit 08bd4c
#include <unistd.h>

Packit 08bd4c
Packit 08bd4c

struct mydata {

Packit 08bd4c

Packit 08bd4c
const char *name; 
Packit 08bd4c
int fd; 
Packit 08bd4c
};

Packit 08bd4c
Packit 08bd4c

int

Packit 08bd4c
myopen(struct archive *a, void *client_data) 
Packit 08bd4c
{ 
Packit 08bd4c
struct mydata *mydata = client_data;

Packit 08bd4c
Packit 08bd4c

mydata->fd =

Packit 08bd4c
open(mydata->name, O_WRONLY | O_CREAT, 0644); 
Packit 08bd4c
if (mydata->fd >= 0) 
Packit 08bd4c
return (ARCHIVE_OK); 
Packit 08bd4c
else 
Packit 08bd4c
return (ARCHIVE_FATAL); 
Packit 08bd4c
}

Packit 08bd4c
Packit 08bd4c

la_ssize_t

Packit 08bd4c
mywrite(struct archive *a, void *client_data, const void
Packit 08bd4c
*buff, size_t n) 
Packit 08bd4c
{ 
Packit 08bd4c
struct mydata *mydata = client_data;

Packit 08bd4c
Packit 08bd4c

return

Packit 08bd4c
(write(mydata->fd, buff, n)); 
Packit 08bd4c
}

Packit 08bd4c
Packit 08bd4c

int

Packit 08bd4c
myclose(struct archive *a, void *client_data) 
Packit 08bd4c
{ 
Packit 08bd4c
struct mydata *mydata = client_data;

Packit 08bd4c
Packit 08bd4c

if

Packit 08bd4c
(mydata->fd > 0) 
Packit 08bd4c
close(mydata->fd); 
Packit 08bd4c
return (0); 
Packit 08bd4c
}

Packit 08bd4c
Packit 08bd4c

void

Packit 08bd4c
write_archive(const char *outname, const char **filename)
Packit 08bd4c

Packit 08bd4c
{ 
Packit 08bd4c
struct mydata *mydata = malloc(sizeof(struct mydata)); 
Packit 08bd4c
struct archive *a; 
Packit 08bd4c
struct archive_entry *entry; 
Packit 08bd4c
struct stat st; 
Packit 08bd4c
char buff[8192]; 
Packit 08bd4c
int len; 
Packit 08bd4c
int fd;

Packit 08bd4c
Packit 08bd4c

a =

Packit 08bd4c
archive_write_new(); 
Packit 08bd4c
mydata->name = outname; 
Packit 08bd4c
/* Set archive format and filter according to output file
Packit 08bd4c
extension. 
Packit 08bd4c
* If it fails, set default format. Platform depended
Packit 08bd4c
function. 
Packit 08bd4c
* See supported formats in
Packit 08bd4c
archive_write_set_format_filter_by_ext.c */ 
Packit 08bd4c
if (archive_write_set_format_filter_by_ext(a, outname) !=
Packit 08bd4c
ARCHIVE_OK) { 
Packit 08bd4c
archive_write_add_filter_gzip(a); 
Packit 08bd4c
archive_write_set_format_ustar(a); 
Packit 08bd4c
} 
Packit 08bd4c
archive_write_open(a, mydata, myopen, mywrite, myclose);
Packit 08bd4c

Packit 08bd4c
while (*filename) { 
Packit 08bd4c
stat(*filename, &st); 
Packit 08bd4c
entry = archive_entry_new(); 
Packit 08bd4c
archive_entry_copy_stat(entry, &st); 
Packit 08bd4c
archive_entry_set_pathname(entry, *filename); 
Packit 08bd4c
archive_write_header(a, entry); 
Packit 08bd4c
if ((fd = open(*filename, O_RDONLY)) != -1) { 
Packit 08bd4c
len = read(fd, buff, sizeof(buff)); 
Packit 08bd4c
while (len > 0) { 
Packit 08bd4c
archive_write_data(a, buff, len); 
Packit 08bd4c
len = read(fd, buff, sizeof(buff)); 
Packit 08bd4c
} 
Packit 08bd4c
close(fd); 
Packit 08bd4c
} 
Packit 08bd4c
archive_entry_free(entry); 
Packit 08bd4c
filename++; 
Packit 08bd4c
} 
Packit 08bd4c
archive_write_free(a); 
Packit 08bd4c
}

Packit 08bd4c
Packit 08bd4c

int main(int

Packit 08bd4c
argc, const char **argv) 
Packit 08bd4c
{ 
Packit 08bd4c
const char *outname; 
Packit 08bd4c
argv++; 
Packit 08bd4c
outname = *argv++; 
Packit 08bd4c
write_archive(outname, argv); 
Packit 08bd4c
return 0; 
Packit 08bd4c
}

Packit 08bd4c
Packit 08bd4c

SEE ALSO

Packit 08bd4c
Packit 08bd4c

tar(1), libarchive(3),

Packit 08bd4c
archive_write_set_options(3), cpio(5), mtree(5), tar(5)

Packit 08bd4c
Packit 08bd4c

HISTORY

Packit 08bd4c
Packit 08bd4c

The libarchive library

Packit 08bd4c
first appeared in FreeBSD 5.3.

Packit 08bd4c
Packit 08bd4c

AUTHORS

Packit 08bd4c
Packit 08bd4c

The libarchive library

Packit 08bd4c
was written by Tim Kientzle <kientzle@acm.org>.

Packit 08bd4c
Packit 08bd4c

BUGS

Packit 08bd4c
Packit 08bd4c

There are many peculiar bugs in

Packit 08bd4c
historic tar implementations that may cause certain programs
Packit 08bd4c
to reject archives written by this library. For example,
Packit 08bd4c
several historic implementations calculated header checksums
Packit 08bd4c
incorrectly and will thus reject valid archives; GNU tar
Packit 08bd4c
does not fully support pax interchange format; some old tar
Packit 08bd4c
implementations required specific field terminations.

Packit 08bd4c
Packit 08bd4c

The default pax

Packit 08bd4c
interchange format eliminates most of the historic tar
Packit 08bd4c
limitations and provides a generic key/value attribute
Packit 08bd4c
facility for vendor-defined extensions. One oversight in
Packit 08bd4c
POSIX is the failure to provide a standard attribute for
Packit 08bd4c
large device numbers. This library uses
Packit 08bd4c
’’SCHILY.devminor’’ and
Packit 08bd4c
’’SCHILY.devmajor’’ for device
Packit 08bd4c
numbers that exceed the range supported by the
Packit 08bd4c
backwards-compatible ustar header. These keys are compatible
Packit 08bd4c
with Joerg Schilling’s star archiver. Other
Packit 08bd4c
implementations may not recognize these keys and will thus
Packit 08bd4c
be unable to correctly restore device nodes with large
Packit 08bd4c
device numbers from archives created by this library.

Packit 08bd4c
Packit 08bd4c

BSD

Packit 08bd4c
February 2, 2012 BSD

Packit 08bd4c

Packit 08bd4c
</body>
Packit 08bd4c
</html>