CODEWITHSUNDEEP
c++archive
oggmonster
oggmonster

Reputation: 4872

libarchive - Extract to specified directory

I have a tar file I want to extract with libarchive to a specific directory. How can I make libarchive extract into to any directory I want? At the moment it always extracts into my program's working directory. I looked at this answer but all this does is change the location of an archive entry within the archive, i.e. it still extracts into my program's working directory just at a different sub-directory.

Upvotes: 15

Views: 11342

Answers (3)

oggmonster
oggmonster

Reputation: 4872

From the libarchive discussion boards:

"It depends, of course, on the archive being extracted.

Typically, you would chdir() to the directory where you want the output to go, then use code similar to that in the Wiki Examples page:

A Complete Extractor Example

or in the untar.c sample program:

untar Example

Of course, if the tar file you're extracting has interesting filenames (such as "c:\someotherdirectory"), then you'll need to play with the filenames as you extract.

Note that the examples all use archive_read_next_header() to get an entry object from the input archive describing the next entry; you are then free to edit that entry description in any way you wish -- in particular, you can change the name, owner, or permissions -- before calling archive_write_header() to recreate the entry on disk.

The Examples page in the Wiki above is probably the best place to start."

Upvotes: 8

shuckc
shuckc

Reputation: 2994

A longer C version of Alex's answer. To extract files to a temp_dir, use archive_entry_pathname() and archive_entry_set_pathname() to re-write each entry::

char* dest_file;

for (;;) {
    r = archive_read_next_header(a, &entry);
    if (r == ARCHIVE_EOF)
      break;
    if (r < ARCHIVE_OK)
      fprintf(stderr, "%s\n", archive_error_string(a));
    if (r < ARCHIVE_WARN)
      return NULL;

    asprintf(&dest_file, "%s/%s", temp_dir, archive_entry_pathname(entry));
    archive_entry_set_pathname(entry, dest_file);
    // printf(" writing %s\n", dest_file);

    r = archive_write_header(ext, entry);
    if (r < ARCHIVE_OK)
      fprintf(stderr, "%s\n", archive_error_string(ext));
    else if (archive_entry_size(entry) > 0) {
      r = copy_data(a, ext);
      if (r < ARCHIVE_OK)
        fprintf(stderr, "%s\n", archive_error_string(ext));
      if (r < ARCHIVE_WARN)
        exit(1);
    }
    r = archive_write_finish_entry(ext);
    if (r < ARCHIVE_OK)
      fprintf(stderr, "%s\n", archive_error_string(ext));
    if (r < ARCHIVE_WARN)
      return NULL;

    free(dest_file);
}

Upvotes: 0

Hardwired
Hardwired

Reputation: 834

I resolved this issue next way: (insert this code before calling 'archive_write_header' function)

    const char* currentFile = archive_entry_pathname(archiveEntry);
    const std::string fullOutputPath = destination + currentFile;
    archive_entry_set_pathname(archiveEntry, fullOutputPath.c_str());

where destination is output path. And it works.

Upvotes: 30

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