;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2021 Andrew Tropin ;;; Copyright © 2021 Xinglu Chen ;;; Copyright © 2022 Ludovic Courtès ;;; ;;; This file is part of GNU Guix. ;;; ;;; GNU Guix is free software; you can redistribute it and/or modify it ;;; under the terms of the GNU General Public License as published by ;;; the Free Software Foundation; either version 3 of the License, or (at ;;; your option) any later version. ;;; ;;; GNU Guix is distributed in the hope that it will be useful, but ;;; WITHOUT ANY WARRANTY; without even the implied warranty of ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;;; GNU General Public License for more details. ;;; ;;; You should have received a copy of the GNU General Public License ;;; along with GNU Guix. If not, see . (define-module (gnu home services symlink-manager) #:use-module (gnu home services) #:use-module (guix gexp) #:use-module (guix modules) #:export (home-symlink-manager-service-type)) ;;; Comment: ;;; ;;; symlink-manager cares about xdg configurations and other files: it backs ;;; up files created by user, removes symlinks and directories created by a ;;; previous generation, and creates new directories and symlinks to files ;;; according to the content of directories (created by home-files-service) of ;;; the current home environment generation. ;;; ;;; Code: (define (update-symlinks-script) (program-file "update-symlinks" (with-imported-modules (source-module-closure '((guix build utils) (guix i18n))) #~(begin (use-modules (ice-9 ftw) (ice-9 match) (srfi srfi-1) (guix i18n) (guix build utils)) (define home-directory (getenv "
#include "references.hh"
#include "hash.hh"
#include "util.hh"
#include "archive.hh"

#include <map>
#include <cstdlib>


namespace nix {


static unsigned int refLength = 32; /* characters */


static void search(const unsigned char * s, unsigned int len, 
    StringSet & hashes, StringSet & seen)
{
    static bool initialised = false;
    static bool isBase32[256];
    if (!initialised) {
        for (unsigned int i = 0; i < 256; ++i) isBase32[i] = false;
        for (unsigned int i = 0; i < base32Chars.size(); ++i)
            isBase32[(unsigned char) base32Chars[i]] = true;
        initialised = true;
    }
    
    for (unsigned int i = 0; i + refLength <= len; ) {
        int j;
        bool match = true;
        for (j = refLength - 1; j >= 0; --j)
            if (!isBase32[(unsigned char) s[i + j]]) {
                i += j + 1;
                match = false;
                break;
            }
        if (!match) continue;
        string ref((const char *) s + i, refLength);
        if (hashes.find(ref) != hashes.end()) {
            debug(format("found reference to `%1%' at offset `%2%'")
                  % ref % i);
            seen.insert(ref);
            hashes.erase(ref);
        }
        ++i;
    }
}


struct RefScanSink : Sink
{
    HashSink hashSink;
    StringSet hashes;
    StringSet seen;

    string tail;

    RefScanSink() : hashSink(htSHA256) { }
    
    void operator () (const unsigned char * data, size_t len);
};


void RefScanSink::operator () (const unsigned char * data, size_t len)
{
    hashSink(data, len);

    /* It's possible that a reference spans the previous and current
       fragment, so search in the concatenation of the tail of the
       previous fragment and the start of the current fragment. */
    string s = tail + string((const char *) data, len > refLength ? refLength : len);
    search((const unsigned char *) s.data(), s.size(), hashes, seen);

    search(data, len, hashes, seen);

    unsigned int tailLen = len <= refLength ? len : refLength;
    tail =
        string(tail, tail.size() < refLength - tailLen ? 0 : tail.size() - (refLength - tailLen)) +
        string((const char *) data + len - tailLen, tailLen);
}


PathSet scanForReferences(const string & path,
    const PathSet & refs, HashResult & hash)
{
    RefScanSink sink;
    std::map<string, Path> backMap;

    /* For efficiency (and a higher hit rate), just search for the
       hash part of the file name.  (This assumes that all references
       have the form `HASH-bla'). */
    foreach (PathSet::const_iterator, i, refs) {
        string baseName = baseNameOf(*i);
        string::size_type pos = baseName.find('-');
        if (pos == string::npos)
            throw Error(format("bad reference `%1%'") % *i);
        string s = string(baseName, 0, pos);
        assert(s.size() == refLength);
        assert(backMap.find(s) == backMap.end());
        // parseHash(htSHA256, s);
        sink.hashes.insert(s);
        backMap[s] = *i;
    }

    /* Look for the hashes in the NAR dump of the path. */
    dumpPath(path, sink);

    /* Map the hashes found back to their store paths. */
    PathSet found;
    foreach (StringSet::iterator, i, sink.seen) {
        std::map<string, Path>::iterator j;
        if ((j = backMap.find(*i)) == backMap.end()) abort();
        found.insert(j->second);
    }

    hash = sink.hashSink.finish();
        
    return found;
}


}
generated by cgit
less (string=? directory config-file-directory) (let ((directory (target-file (strip directory)))) (catch 'system-error (lambda () (rmdir directory) (format #t (G_ "Removed ~a.\n") directory)) (lambda args (let ((errno (system-error-errno args))) (cond ((= ENOTEMPTY errno) (format #t (G_ "Skipping ~a (not an empty directory)... done\n") directory)) ((= ENOENT errno) #t) ((= ENOTDIR errno) #t) (else (apply throw args))))))))) (const #t) ;skip (const #t) ;error #t ;init config-file-directory lstat) (display (G_ "Cleanup finished.\n\n"))) (define (create-symlinks home-generation) ;; Create in $HOME symlinks for the files in HOME-GENERATION. (define config-file-directory ;; Note: Trailing slash is needed because "files" is a symlink. (string-append home-generation "/" #$home-files-directory "/")) (define (strip file) (string-drop file (+ 1 (string-length config-file-directory)))) (define (source-file file) (readlink (string-append config-file-directory file))) (file-system-fold (const #t) ;enter? (lambda (file stat result) ;leaf (let ((source (source-file (strip file))) (target (target-file (strip file)))) (when (no-follow-file-exists? target) (backup-file (strip file))) (format #t (G_ "Symlinking ~a -> ~a...") target source) (symlink source target) (display (G_ " done\n")))) (lambda (directory stat result) ;down (unless (string=? directory config-file-directory) (let ((target (target-file (strip directory)))) (when (and (no-follow-file-exists? target) (not (file-is-directory? target))) (backup-file (strip directory))) (catch 'system-error (lambda () (mkdir target)) (lambda args (let ((errno (system-error-errno args))) (unless (= EEXIST errno) (format #t (G_ "failed to create directory ~a: ~s~%") target (strerror errno)) (apply throw args)))))))) (const #t) ;up (const #t) ;skip (const #t) ;error #t ;init config-file-directory)) #$%initialize-gettext (let* ((home (string-append home-directory "/.guix-home")) (pivot (string-append home ".new")) (new-home (getenv "GUIX_NEW_HOME")) (old-home (getenv "GUIX_OLD_HOME"))) (when old-home (cleanup-symlinks old-home)) (create-symlinks new-home) (symlink new-home pivot) (rename-file pivot home) (display (G_" done\nFinished updating symlinks.\n\n"))))))) (define (update-symlinks-gexp _) #~(primitive-load #$(update-symlinks-script))) (define home-symlink-manager-service-type (service-type (name 'home-symlink-manager) (extensions (list (service-extension home-activation-service-type update-symlinks-gexp))) (default-value #f) (description "Provide an @code{update-symlinks} script, which creates symlinks to configuration files and directories on every activation. If an existing file would be overwritten by a symlink, backs up that file first.")))