114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
/*
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* This file is in the public domain.
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*
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* Feel free to use it as you wish.
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*/
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/*
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* This example program reads an archive from stdin (which can be in
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* any format recognized by libarchive) and writes certain entries to
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* an uncompressed ustar archive on stdout. This is a template for
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* many kinds of archive manipulation: converting formats, resetting
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* ownership, inserting entries, removing entries, etc.
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*
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* To compile:
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* gcc -Wall -o tarfilter tarfilter.c -larchive -lz -lbz2
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*/
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#include <sys/stat.h>
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#include <archive.h>
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#include <archive_entry.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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static void
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die(char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vfprintf(stderr, fmt, ap);
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va_end(ap);
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fprintf(stderr, "\n");
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exit(1);
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}
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int
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main(int argc, char **argv)
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{
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char buff[8192];
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ssize_t len;
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int r;
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mode_t m;
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struct archive *ina;
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struct archive *outa;
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struct archive_entry *entry;
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/* Read an archive from stdin, with automatic format detection. */
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ina = archive_read_new();
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if (ina == NULL)
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die("Couldn't create archive reader.");
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if (archive_read_support_compression_all(ina) != ARCHIVE_OK)
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die("Couldn't enable decompression");
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if (archive_read_support_format_all(ina) != ARCHIVE_OK)
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die("Couldn't enable read formats");
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if (archive_read_open_fd(ina, 0, 10240) != ARCHIVE_OK)
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die("Couldn't open input archive");
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/* Write an uncompressed ustar archive to stdout. */
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outa = archive_write_new();
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if (outa == NULL)
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die("Couldn't create archive writer.");
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if (archive_write_set_compression_none(outa) != ARCHIVE_OK)
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die("Couldn't enable compression");
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if (archive_write_set_format_ustar(outa) != ARCHIVE_OK)
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die("Couldn't set output format");
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if (archive_write_open_fd(outa, 1) != ARCHIVE_OK)
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die("Couldn't open output archive");
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/* Examine each entry in the input archive. */
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while ((r = archive_read_next_header(ina, &entry)) == ARCHIVE_OK) {
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fprintf(stderr, "%s: ", archive_entry_pathname(entry));
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/* Skip anything that isn't a regular file. */
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if (!S_ISREG(archive_entry_mode(entry))) {
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fprintf(stderr, "skipped\n");
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continue;
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}
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/* Make everything owned by root/wheel. */
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archive_entry_set_uid(entry, 0);
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archive_entry_set_uname(entry, "root");
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archive_entry_set_gid(entry, 0);
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archive_entry_set_gname(entry, "wheel");
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/* Make everything permission 0744, strip SUID, etc. */
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m = archive_entry_mode(entry);
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archive_entry_set_mode(entry, (m & ~07777) | 0744);
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/* Copy input entries to output archive. */
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if (archive_write_header(outa, entry) != ARCHIVE_OK)
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die("Error writing output archive");
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if (archive_entry_size(entry) > 0) {
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len = archive_read_data(ina, buff, sizeof(buff));
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while (len > 0) {
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if (archive_write_data(outa, buff, len) != len)
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die("Error writing output archive");
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len = archive_read_data(ina, buff, sizeof(buff));
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}
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if (len < 0)
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die("Error reading input archive");
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}
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fprintf(stderr, "copied\n");
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}
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if (r != ARCHIVE_EOF)
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die("Error reading archive");
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/* Close the archives. */
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if (archive_read_finish(ina) != ARCHIVE_OK)
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die("Error closing input archive");
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if (archive_write_finish(outa) != ARCHIVE_OK)
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die("Error closing output archive");
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return (0);
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}
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