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I just want to extract the contents into a directory. I have no problem opening the archive, getting the number of files in the archive, using a for loop for the number of files to stat the files by index, open a file with the filename that corresponds to that index, run a read and write while loop, then close the file and close the zip archive. However, the issue is that some filenames that I get from the zip_stat_index are prepended with a directory. It would have been nice if the directory was listed on its own as a separate index but it is not. I don't see any options in the open system call to create one or more parent directories if the filename being opened/created is under one or more directories.
Here is my code so far
Code:
#include <zip.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define BUFSIZE 4096
int main()
{
int i = 0;
int x = 0;
int n = 0;
int file = 0;
zip_int64_t *zipfile;
char buf[BUFSIZE];
struct zip *z;
struct zip_stat st;
int err = 0;
z = zip_open("/usr/share/httpd/mapcrafter/worlds/Freehold/freehold.zip", 0, &err);
zip_stat_init(&st);
x = zip_get_num_files(z);
printf("There are %i number of files in this archive.\n", x);
printf("Here is a list of the files in the archive.\n");
for (i = 0; i < x; i++) {
zip_stat_index(z, i, 0, &st);
file = open(st.name, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
zipfile = zip_fopen_index(z, i, 0);
while ((n = read(zipfile, buf, sizeof buf)) > 0)
write(file, buf, n);
close(file);
zip_fclose(zipfile);
printf("Copied %s...\n", st.name);
}
zip_close(z);
return 0;
}
I mean do I really have to stat each index and scan for "/" to see if that index contains a directory? There must be an easier way. Here are the docs for the libzip library. Thank you!!
the issue is that some filenames that I get from the zip_stat_index are prepended with a directory. It would have been nice if the directory was listed on its own as a separate index but it is not.
Code:
There are 222 number of files in this archive.
Here is a list of the files in the archive.
Copied DIM1/region/...
Copied DIM1/region/r.0.0.mca...
Copied DIM1/region/r.0.1.mca...
Copied DIM1/region/r.0.-1.mca...
Copied DIM1/region/r.0.2.mca...
I haven't checked the whole stat output inclusively, but I was thinking that what you said, "It would have been nice if the directory was listed on its own as a separate index" is exactly what things like zip and tar do.
Is not /DIM1/region/ a directory? And therefore it is there.
Added: OK a more detailed review shows that this is not universal. Plus it doesn't show DIM1/... for instance or some number of other ones.
Does a command line listing of this archive show the same 222 entries? Other than that, I have no understanding any better than you.
Yea you're right, I unzipped it and I got 230 entries instead of 222. Ok thanks.
-Tristan
Wow! What's up with that library then?!? I mean ... is it NOT the same code being used by the command line? Or nearly/very close? Maybe check that out. I can see that there would be several versions, or potentially a different library...
You should create a `pathopen` that splits filenames and creates the missing directories. While doing this, you should check for '..' as directoy-name, e.g. `src/../../../../etc/passwd`.
Note: opening an existing file can be problematic (e.g. symlink attack or text-file-busy problems) instead you could create the file on a temporary name in the same directory then `rename` to the final name.
I mean do I really have to stat each index and scan for "/" to see if that index contains a directory?
Yes. Usually there will be a separate entry for the directory in a ZIP archive (and there was in your case; it was the entry ending in a slash) but in general that’s not a guarantee. If you want your code to be robust, you should split and the name and check for all the directories on the path.
Quote:
Originally Posted by NevemTeve
Note: opening an existing file can be problematic (e.g. symlink attack or text-file-busy problems)
Worth noting that symlink attack may be performed with the leaf file name as well as with a directory on the path. E.g. one could craft a ZIP archive with ‘foo’ being symbolic link to ‘/etc/passwd’ and then another entry which overwrites contents of ‘foo’ but one could also craft a ZIP archive with ‘foo’ being symbolic link to ‘/etc’ and then have another entry ‘foo/passwd’ which overwrites contents of ‘passwd’.
To combat that, a good extracting tool should verify that whatever it creates is under the directory it was told to extract the archive into.
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