/*

 * This file is in the public domain.

 *

 * Feel free to use it as you wish.

 */

/*

 * This example program reads an archive from stdin (which can be in

 * any format recognized by libarchive) and writes certain entries to

 * an uncompressed ustar archive on stdout.  This is a template for

 * many kinds of archive manipulation: converting formats, resetting

 * ownership, inserting entries, removing entries, etc.

 *

 * To compile:

 * gcc -Wall -o tarfilter tarfilter.c -larchive -lz -lbz2

 */

#include <sys/stat.h>

#include <archive.h>

#include <archive_entry.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

static void

die(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

	fprintf(stderr, "\n");

	exit(1);

}

int

main(int argc, char **argv)

{

	char buff[8192];

	ssize_t len;

	int r;

	mode_t m;

	struct archive *ina;

	struct archive *outa;

	struct archive_entry *entry;

	/* Read an archive from stdin, with automatic format detection. */

	ina = archive_read_new();

	if (ina == NULL)

		die("Couldn't create archive reader.");

	if (archive_read_support_filter_all(ina) != ARCHIVE_OK)

		die("Couldn't enable decompression");

	if (archive_read_support_format_all(ina) != ARCHIVE_OK)

		die("Couldn't enable read formats");

	if (archive_read_open_fd(ina, 0, 10240) != ARCHIVE_OK)

		die("Couldn't open input archive");

	/* Write an uncompressed ustar archive to stdout. */

	outa = archive_write_new();

	if (outa == NULL)

		die("Couldn't create archive writer.");

	if (archive_write_set_compression_none(outa) != ARCHIVE_OK)

		die("Couldn't enable compression");

	if (archive_write_set_format_ustar(outa) != ARCHIVE_OK)

		die("Couldn't set output format");

	if (archive_write_open_fd(outa, 1) != ARCHIVE_OK)

		die("Couldn't open output archive");

	/* Examine each entry in the input archive. */

	while ((r = archive_read_next_header(ina, &entry)) == ARCHIVE_OK) {

		fprintf(stderr, "%s: ", archive_entry_pathname(entry));

		/* Skip anything that isn't a regular file. */

		if (!S_ISREG(archive_entry_mode(entry))) {

			fprintf(stderr, "skipped\n");

			continue;

		}

		/* Make everything owned by root/wheel. */

		archive_entry_set_uid(entry, 0);

		archive_entry_set_uname(entry, "root");

		archive_entry_set_gid(entry, 0);

		archive_entry_set_gname(entry, "wheel");

		/* Make everything permission 0744, strip SUID, etc. */

		m = archive_entry_mode(entry);

		archive_entry_set_mode(entry, (m & ~07777) | 0744);

		/* Copy input entries to output archive. */

		if (archive_write_header(outa, entry) != ARCHIVE_OK)

			die("Error writing output archive");

		if (archive_entry_size(entry) > 0) {

			len = archive_read_data(ina, buff, sizeof(buff));

			while (len > 0) {

				if (archive_write_data(outa, buff, len) != len)

					die("Error writing output archive");

				len = archive_read_data(ina, buff, sizeof(buff));

			}

			if (len < 0)

				die("Error reading input archive");

		}

		fprintf(stderr, "copied\n");

	}

	if (r != ARCHIVE_EOF)

		die("Error reading archive");

	/* Close the archives.  */

	if (archive_read_free(ina) != ARCHIVE_OK)

		die("Error closing input archive");

	if (archive_write_free(outa) != ARCHIVE_OK)

		die("Error closing output archive");

	return (0);

}