Updatedb include the path pointed by symbolic link

Question

I have created mlocate database with the contents of a particular folder. I see that the updatedb doesn't include the path pointed by the symbolic links in the database.

How can I include the path pointed by the symbolic links in the database?

Surprisingly: mlocate has a default option -L or --follow that follows trailing symbolic links when checking file existence (default).

What purpose does it serves when updatedb doesn't include symlinks!

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References:

• updatedb(8): update database for mlocate - Linux man page
• mlocate - Gentoo Wiki

Answer 1

Using this implementation of plocate with updatedb in it, one can build a custom version to follow symlinks. I don't know if it answers the question also for mlocate, I only use plocate.

If you are certain there will be no loop in your filesystem, you can simply replace the code

e.is_directory = (de->d_type == DT_DIR);

by

e.is_directory = (de->d_type == DT_DIR) || (de->d_type == DT_LNK); // or even just true

in the file updatedb.cpp.

If you might have loops, here is a solution (maybe not very efficient). Always in updatedb.cpp, declare a global variable vector<char*> explored; just before the function int scan(...). Then, add the following code after the two first tests in that function scan:

char buf[PATH_MAX];
realpath(path.c_str(),buf);
for (auto &e : explored)
  if (strcmp(e,buf) == 0)
    return 0;
explored.push_back(buf);

And just before each return of that function, add an explored.pop_back();.

With similar modifications of the code, one can follow symlinks only when inside certain directories, and/or completely exclude some directories of the database, depending on one's need. It is also quite useful to make the results clickable.