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dpkg-divert: Rewrite in C

Guillem Jover преди 16 години
родител
ревизия
02b12d75f1
променени са 9 файла, в които са добавени 773 реда и са изтрити 375 реда
  1. 1 0
      debian/changelog
  2. 1 2
      po/POTFILES.in
  3. 0 1
      scripts/.gitignore
  4. 0 2
      scripts/Makefile.am
  5. 0 369
      scripts/dpkg-divert.pl
  6. 1 1
      scripts/t/950_dpkg_divert.t
  7. 1 0
      src/.gitignore
  8. 12 0
      src/Makefile.am
  9. 757 0
      src/divertcmd.c

+ 1 - 0
debian/changelog

@@ -61,6 +61,7 @@ dpkg (1.15.8) UNRELEASED; urgency=low
   * Check version syntax when parsing it from libdpkg based programs.
     Closes: #574704
   * Rewrite mksplit in C, and merge it into dpkg-split.
+  * Rewrite dpkg-divert in C.
 
   [ Updated programs translations ]
   * Catalan (Guillem Jover).

+ 1 - 2
po/POTFILES.in

@@ -38,6 +38,7 @@ src/archives.c
 src/cleanup.c
 src/configure.c
 src/depcon.c
+src/divertcmd.c
 src/divertdb.c
 src/enquiry.c
 src/errors.c
@@ -69,5 +70,3 @@ dpkg-split/split.c
 
 utils/start-stop-daemon.c
 utils/update-alternatives.c
-
-scripts/dpkg-divert.pl

+ 0 - 1
scripts/.gitignore

@@ -3,7 +3,6 @@ dpkg-buildflags
 dpkg-buildpackage
 dpkg-checkbuilddeps
 dpkg-distaddfile
-dpkg-divert
 dpkg-genchanges
 dpkg-gencontrol
 dpkg-gensymbols

+ 0 - 2
scripts/Makefile.am

@@ -8,7 +8,6 @@ bin_SCRIPTS = \
 	dpkg-buildpackage \
 	dpkg-checkbuilddeps \
 	dpkg-distaddfile \
-	dpkg-divert \
 	dpkg-genchanges \
 	dpkg-gencontrol \
 	dpkg-gensymbols \
@@ -43,7 +42,6 @@ EXTRA_DIST = \
 	dpkg-scansources.pl \
 	dpkg-shlibdeps.pl \
 	dpkg-source.pl \
-	dpkg-divert.pl \
 	dpkg-vendor.pl \
 	changelog/debian.pl \
 	$(test_cases) \

+ 0 - 369
scripts/dpkg-divert.pl

@@ -1,369 +0,0 @@
-#!/usr/bin/perl
-#
-# dpkg-divert
-#
-# This program 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 2 of the License, or
-# (at your option) any later version.
-#
-# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
-
-BEGIN { # Work-around for bug #479711 in perl
-    $ENV{PERL_DL_NONLAZY} = 1;
-}
-
-use strict;
-use warnings;
-
-use POSIX qw(:errno_h);
-use Dpkg;
-use Dpkg::Gettext;
-
-textdomain("dpkg");
-
-sub version {
-    printf _g("Debian %s version %s.\n"), $progname, $version;
-
-    printf _g("
-Copyright (C) 1995 Ian Jackson.
-Copyright (C) 2000,2001 Wichert Akkerman.");
-
-    printf "\n" . _g(
-"This is free software; see the GNU General Public License version 2 or
-later for copying conditions. There is NO warranty.
-");
-}
-
-sub usage {
-    printf(_g(
-"Usage: %s [<option> ...] <command>
-
-Commands:
-  [--add] <file>           add a diversion.
-  --remove <file>          remove the diversion.
-  --list [<glob-pattern>]  show file diversions.
-  --listpackage <file>     show what package diverts the file.
-  --truename <file>        return the diverted file.
-
-Options:
-  --package <package>      name of the package whose copy of <file> will not
-                             be diverted.
-  --local                  all packages' versions are diverted.
-  --divert <divert-to>     the name used by other packages' versions.
-  --rename                 actually move the file aside (or back).
-  --admindir <directory>   set the directory with the diversions file.
-  --test                   don't do anything, just demonstrate.
-  --quiet                  quiet operation, minimal output.
-  --help                   show this help message.
-  --version                show the version.
-
-When adding, default is --local and --divert <original>.distrib.
-When removing, --package or --local and --divert must match if specified.
-Package preinst/postrm scripts should always specify --package and --divert.
-"), $progname);
-}
-
-my $testmode = 0;
-my $dorename = 0;
-my $verbose = 1;
-my $mode = '';
-my $package = undef;
-my $divertto = undef;
-my @contest;
-my @altname;
-my @package;
-my $file;
-$|=1;
-
-
-# FIXME: those should be local.
-my ($rsrc, $rdest);
-my (@ssrc, @sdest);
-
-sub checkmanymodes {
-    return unless $mode;
-    badusage(sprintf(_g("two commands specified: %s and --%s"), $_, $mode));
-}
-
-while (@ARGV) {
-    $_= shift(@ARGV);
-    last if m/^--$/;
-    if (!m/^-/) {
-        unshift(@ARGV,$_); last;
-    } elsif (m/^--help$/) {
-        usage();
-        exit(0);
-    } elsif (m/^--version$/) {
-        version();
-        exit(0);
-    } elsif (m/^--test$/) {
-        $testmode= 1;
-    } elsif (m/^--rename$/) {
-        $dorename= 1;
-    } elsif (m/^--quiet$/) {
-        $verbose= 0;
-    } elsif (m/^--local$/) {
-        $package= ':';
-    } elsif (m/^--add$/) {
-        checkmanymodes();
-        $mode= 'add';
-    } elsif (m/^--remove$/) {
-        checkmanymodes();
-        $mode= 'remove';
-    } elsif (m/^--list$/) {
-        checkmanymodes();
-        $mode= 'list';
-    } elsif (m/^--listpackage$/) {
-        checkmanymodes();
-        $mode= 'listpackage';
-    } elsif (m/^--truename$/) {
-        checkmanymodes();
-        $mode= 'truename';
-    } elsif (m/^--divert$/) {
-        @ARGV || badusage(sprintf(_g("--%s needs a divert-to argument"), "divert"));
-        $divertto= shift(@ARGV);
-        $divertto =~ m/\n/ && badusage(_g("divert-to may not contain newlines"));
-    } elsif (m/^--package$/) {
-        @ARGV || badusage(sprintf(_g("--%s needs a <package> argument"), "package"));
-        $package= shift(@ARGV);
-        $package =~ m/\n/ && badusage(_g("package may not contain newlines"));
-    } elsif (m/^--admindir$/) {
-        @ARGV || badusage(sprintf(_g("--%s needs a <directory> argument"), "admindir"));
-        $admindir= shift(@ARGV);
-    } else {
-        badusage(sprintf(_g("unknown option \`%s'"), $_));
-    }
-}
-
-$mode='add' unless $mode;
-
-open(O, "$admindir/diversions") || quit(sprintf(_g("cannot open diversions: %s"), $!));
-while(<O>) {
-    s/\n$//; push(@contest,$_);
-    $_ = <O>;
-    s/\n$// || badfmt(_g("missing altname"));
-    push(@altname,$_);
-    $_ = <O>;
-    s/\n$// || badfmt(_g("missing package"));
-    push(@package,$_);
-}
-close(O);
-
-if ($mode eq 'add') {
-    @ARGV == 1 || badusage(sprintf(_g("--%s needs a single argument"), "add"));
-    $file= $ARGV[0];
-    $file =~ m#^/# || badusage(sprintf(_g("filename \"%s\" is not absolute"), $file));
-    $file =~ m/\n/ && badusage(_g("file may not contain newlines"));
-    -d $file && badusage(_g("Cannot divert directories"));
-    $divertto= "$file.distrib" unless defined($divertto);
-    $divertto =~ m#^/# || badusage(sprintf(_g("filename \"%s\" is not absolute"), $divertto));
-    $file ne $divertto || badusage(sprintf(_g("cannot divert file '%s' to itself"), $file));
-    $package= ':' unless defined($package);
-    for (my $i = 0; $i <= $#contest; $i++) {
-        if ($contest[$i] eq $file || $altname[$i] eq $file ||
-            $contest[$i] eq $divertto || $altname[$i] eq $divertto) {
-            if ($contest[$i] eq $file && $altname[$i] eq $divertto &&
-                $package[$i] eq $package) {
-                printf(_g("Leaving \`%s'")."\n", infon($i)) if $verbose > 0;
-                exit(0);
-            }
-            quit(sprintf(_g("\`%s' clashes with \`%s'"), infoa(), infon($i)));
-        }
-    }
-    push(@contest,$file);
-    push(@altname,$divertto);
-    push(@package,$package);
-    printf(_g("Adding \`%s'")."\n", infon($#contest)) if $verbose > 0;
-    checkrename($file, $divertto);
-    save();
-    dorename($file, $divertto);
-    exit(0);
-} elsif ($mode eq 'remove') {
-    @ARGV == 1 || badusage(sprintf(_g("--%s needs a single argument"), "remove"));
-    $file= $ARGV[0];
-    for (my $i = 0; $i <= $#contest; $i++) {
-        next unless $file eq $contest[$i];
-        quit(sprintf(_g("mismatch on divert-to\n  when removing \`%s'\n  found \`%s'"), infoa(), infon($i)))
-              if defined($divertto) && $altname[$i] ne $divertto;
-        quit(sprintf(_g("mismatch on package\n  when removing \`%s'\n  found \`%s'"), infoa(), infon($i)))
-              if defined($package) && $package[$i] ne $package;
-        printf(_g("Removing \`%s'")."\n", infon($i)) if $verbose > 0;
-        my $orgfile = $contest[$i];
-        my $orgdivertto = $altname[$i];
-        @contest= (($i > 0 ? @contest[0..$i-1] : ()),
-                   ($i < $#contest ? @contest[$i+1..$#contest] : ()));
-        @altname= (($i > 0 ? @altname[0..$i-1] : ()),
-                   ($i < $#altname ? @altname[$i+1..$#altname] : ()));
-        @package= (($i > 0 ? @package[0..$i-1] : ()),
-                   ($i < $#package ? @package[$i+1..$#package] : ()));
-        checkrename($orgdivertto, $orgfile);
-        dorename($orgdivertto, $orgfile);
-        save();
-        exit(0);
-    }
-    printf(_g("No diversion \`%s', none removed")."\n", infoa())
-        if $verbose > 0;
-    exit(0);
-} elsif ($mode eq 'list') {
-    my @list;
-    my @ilist = @ARGV ? @ARGV : ('*');
-    while (defined($_=shift(@ilist))) {
-        s/\W/\\$&/g;
-        s/\\\?/./g;
-        s/\\\*/.*/g;
-        push(@list,"^$_\$");
-    }
-    my $pat = join('|', @list);
-    for (my $i = 0; $i <= $#contest; $i++) {
-        next unless ($contest[$i] =~ m/$pat/o ||
-                     $altname[$i] =~ m/$pat/o ||
-                     $package[$i] =~ m/$pat/o);
-        print infon($i), "\n";
-    }
-    exit(0);
-} elsif ($mode eq 'truename') {
-    @ARGV == 1 || badusage(sprintf(_g("--%s needs a single argument"), "truename"));
-    $file= $ARGV[0];
-    for (my $i = 0; $i <= $#contest; $i++) {
-	next unless $file eq $contest[$i];
-	print $altname[$i], "\n";
-	exit(0);
-    }
-    print $file, "\n";
-    exit(0);
-} elsif ($mode eq 'listpackage') {
-    @ARGV == 1 || badusage(sprintf(_g("--%s needs a single argument"), $mode));
-    $file= $ARGV[0];
-    for (my $i = 0; $i <= $#contest; $i++) {
-	next unless $file eq $contest[$i];
-	if ($package[$i] eq ':') {
-	    # indicate package is local using something not in package namespace
-	    print "LOCAL\n";
-	} else {
-	    print $package[$i], "\n";
-	}
-	exit(0);
-    }
-    # print nothing if file is not diverted
-    exit(0);
-} else {
-    quit(sprintf(_g("internal error - bad mode \`%s'"), $mode));
-}
-
-sub infol {
-    return ((defined($_[2]) ? ($_[2] eq ':' ? "local " : "") : "any ").
-            "diversion of $_[0]".
-            (defined($_[1]) ? " to $_[1]" : "").
-            (defined($_[2]) && $_[2] ne ':' ? " by $_[2]" : ""));
-}
-
-sub checkrename {
-    return unless $dorename;
-    ($rsrc,$rdest) = @_;
-    (@ssrc = lstat($rsrc)) || $! == ENOENT ||
-        quit(sprintf(_g("cannot stat old name \`%s': %s"), $rsrc, $!));
-    (@sdest = lstat($rdest)) || $! == ENOENT ||
-        quit(sprintf(_g("cannot stat new name \`%s': %s"), $rdest, $!));
-    # Unfortunately we have to check for write access in both
-    # places, just having +w is not enough, since people do
-    # mount things RO, and we need to fail before we start
-    # mucking around with things. So we open a file with the
-    # same name as the diversions but with an extension that
-    # (hopefully) wont overwrite anything. If it succeeds, we
-    # assume a writable filesystem.
-    if (open (TMP, ">>", "${rsrc}.dpkg-devert.tmp")) {
-	close TMP;
-	unlink ("${rsrc}.dpkg-devert.tmp");
-    } elsif ($! == ENOENT) {
-	$dorename = !$dorename;
-	# If the source file is not present and we are not going to do the
-	# rename anyway there's no point in checking the target.
-	return;
-    } else {
-	quit(sprintf(_g("error checking \`%s': %s"), $rsrc, $!));
-    }
-
-    if (open (TMP, ">>", "${rdest}.dpkg-devert.tmp")) {
-	close TMP;
-	unlink ("${rdest}.dpkg-devert.tmp");
-    } else {
-	quit(sprintf(_g("error checking \`%s': %s"), $rdest, $!));
-    }
-    if (@ssrc && @sdest &&
-        !($ssrc[0] == $sdest[0] && $ssrc[1] == $sdest[1])) {
-        quit(sprintf(_g("rename involves overwriting \`%s' with\n".
-                        "  different file \`%s', not allowed"), $rdest, $rsrc));
-    }
-}
-
-sub rename_mv($$)
-{
-    return (rename($_[0], $_[1]) || (system(("mv", $_[0], $_[1])) == 0));
-}
-
-sub dorename {
-    return unless $dorename;
-    return if $testmode;
-    if (@ssrc) {
-        if (@sdest) {
-            unlink($rsrc) || quit(sprintf(_g("rename: remove duplicate old link \`%s': %s"), $rsrc, $!));
-        } else {
-            rename_mv($rsrc, $rdest) ||
-                quit(sprintf(_g("rename: rename \`%s' to \`%s': %s"), $rsrc, $rdest, $!));
-        }
-    }
-}            
-    
-sub save {
-    return if $testmode;
-    open(N, "> $admindir/diversions-new") || quit(sprintf(_g("create diversions-new: %s"), $!));
-    chmod 0644, "$admindir/diversions-new";
-    for (my $i = 0; $i <= $#contest; $i++) {
-        print(N "$contest[$i]\n$altname[$i]\n$package[$i]\n")
-            || quit(sprintf(_g("write diversions-new: %s"), $!));
-    }
-    close(N) || quit(sprintf(_g("close diversions-new: %s"), $!));
-    unlink("$admindir/diversions-old") ||
-        $! == ENOENT || quit(sprintf(_g("remove old diversions-old: %s"), $!));
-    link("$admindir/diversions","$admindir/diversions-old") ||
-        $! == ENOENT || quit(sprintf(_g("create new diversions-old: %s"), $!));
-    rename("$admindir/diversions-new","$admindir/diversions")
-        || quit(sprintf(_g("install new diversions: %s"), $!));
-}
-
-sub infoa
-{
-    infol($file, $divertto, $package);
-}
-
-sub infon
-{
-    my $i = shift;
-    infol($contest[$i], $altname[$i], $package[$i]);
-}
-
-sub quit
-{
-    printf STDERR "%s: %s\n", $progname, "@_";
-    exit(2);
-}
-
-sub badusage
-{
-    printf STDERR "%s: %s\n\n", $progname, "@_";
-    usage();
-    exit(2);
-}
-
-sub badfmt
-{
-    quit(sprintf(_g("internal error: %s corrupt: %s"), "$admindir/diversions", $_[0]));
-}
-

+ 1 - 1
scripts/t/950_dpkg_divert.t

@@ -26,7 +26,7 @@ my $tmpdir = 't.tmp/950_dpkg_divert';
 my $admindir = File::Spec->rel2abs("$tmpdir/admindir");
 my $testdir = File::Spec->rel2abs("$tmpdir/testdir");
 
-my @dd = ("$builddir/dpkg-divert");
+my @dd = ("$builddir/../src/dpkg-divert");
 
 plan tests => 235;
 

+ 1 - 0
src/.gitignore

@@ -1,4 +1,5 @@
 dpkg
+dpkg-divert
 dpkg-query
 dpkg-statoverride
 dpkg-trigger

+ 12 - 0
src/Makefile.am

@@ -14,6 +14,7 @@ AM_CPPFLAGS = \
 
 bin_PROGRAMS = \
 	dpkg \
+	dpkg-divert \
 	dpkg-query \
 	dpkg-statoverride \
 	dpkg-trigger
@@ -45,6 +46,17 @@ dpkg_LDADD = \
 	$(LIBINTL) \
 	$(SELINUX_LIBS)
 
+dpkg_divert_SOURCES = \
+	glob.c glob.h \
+	filesdb.c filesdb.h \
+	divertdb.c \
+	divertcmd.c
+
+dpkg_divert_LDADD = \
+	../lib/dpkg/libdpkg.a \
+	../lib/compat/libcompat.a \
+	$(LIBINTL)
+
 dpkg_query_SOURCES = \
 	filesdb.c filesdb.h \
 	divertdb.c \

+ 757 - 0
src/divertcmd.c

@@ -0,0 +1,757 @@
+/*
+ * dpkg-divert - override a package's version of a file
+ *
+ * Copyright © 1995 Ian Jackson
+ * Copyright © 2000, 2001 Wichert Akkerman
+ * Copyright © 2010 Guillem Jover <guillem@debian.org>
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <compat.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#if HAVE_LOCALE_H
+#include <locale.h>
+#endif
+#include <fcntl.h>
+#include <fnmatch.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <dpkg/i18n.h>
+#include <dpkg/dpkg.h>
+#include <dpkg/dpkg-db.h>
+#include <dpkg/file.h>
+#include <dpkg/buffer.h>
+#include <dpkg/myopt.h>
+
+#include "glob.h"
+#include "filesdb.h"
+
+
+const char thisname[] = "dpkg-divert";
+const char printforhelp[] = N_("Use --help for help about querying packages.");
+
+const struct cmdinfo *cipaction = NULL;
+const char *admindir = ADMINDIR;
+
+static bool opt_pkgname_match_any = true;
+static const char *opt_pkgname = NULL;
+static const char *opt_divertto = NULL;
+
+static int opt_verbose = 1;
+static int opt_test = 0;
+static int opt_rename = 0;
+
+
+static void
+printversion(const struct cmdinfo *cip, const char *value)
+{
+	printf(_("Debian %s version %s.\n"), thisname, DPKG_VERSION_ARCH);
+
+	printf(_(
+"Copyright (C) 1995 Ian Jackson.\n"
+"Copyright (C) 2000,2001 Wichert Akkerman.\n"
+"Copyright (C) 2010 Guillem Jover.\n"));
+
+	printf(_(
+"This is free software; see the GNU General Public License version 2 or\n"
+"later for copying conditions. There is NO warranty.\n"));
+
+	m_output(stdout, _("<standard output>"));
+
+	exit(0);
+}
+
+static void
+usage(const struct cmdinfo *cip, const char *value)
+{
+	printf(_(
+"Usage: %s [<option> ...] <command>\n"
+"\n"), thisname);
+
+	printf(_(
+"Commands:\n"
+"  [--add] <file>           add a diversion.\n"
+"  --remove <file>          remove the diversion.\n"
+"  --list [<glob-pattern>]  show file diversions.\n"
+"  --listpackage <file>     show what package diverts the file.\n"
+"  --truename <file>        return the diverted file.\n"
+"\n"));
+
+	printf(_(
+"Options:\n"
+"  --package <package>      name of the package whose copy of <file> will not\n"
+"                             be diverted.\n"
+"  --local                  all packages' versions are diverted.\n"
+"  --divert <divert-to>     the name used by other packages' versions.\n"
+"  --rename                 actually move the file aside (or back).\n"
+"  --admindir <directory>   set the directory with the diversions file.\n"
+"  --test                   don't do anything, just demonstrate.\n"
+"  --quiet                  quiet operation, minimal output.\n"
+"  --help                   show this help message.\n"
+"  --version                show the version.\n"
+"\n"));
+
+	printf(_(
+"When adding, default is --local and --divert <original>.distrib.\n"
+"When removing, --package or --local and --divert must match if specified.\n"
+"Package preinst/postrm scripts should always specify --package and --divert.\n"));
+
+	m_output(stdout, _("<standard output>"));
+
+	exit(0);
+}
+
+struct file {
+	const char *name;
+	enum {
+		file_stat_invalid,
+		file_stat_valid,
+		file_stat_nofile,
+	} stat_state;
+	struct stat stat;
+};
+
+static void
+file_init(struct file *f, const char *filename)
+{
+	f->name = filename;
+	f->stat_state = file_stat_invalid;
+}
+
+static void
+file_stat(struct file *f)
+{
+	int ret;
+
+	if (f->stat_state != file_stat_invalid)
+		return;
+
+	ret = lstat(f->name, &f->stat);
+	if (ret && errno != ENOENT)
+		ohshite(_("cannot stat file '%s'"), f->name);
+
+	if (ret == 0)
+		f->stat_state = file_stat_valid;
+	else
+		f->stat_state = file_stat_nofile;
+}
+
+static bool
+check_rename(struct file *src, struct file *dst)
+{
+	struct varbuf tmpname = VARBUF_INIT;
+	int tmpfd;
+
+	file_stat(src);
+	file_stat(dst);
+
+	/*
+	 * Unfortunately we have to check for write access in both places,
+	 * just having +w is not enough, since people do mount things RO,
+	 * and we need to fail before we start mucking around with things.
+	 * So we open a file with the same name as the diversions but with
+	 * an extension that (hopefully) wont overwrite anything. If it
+	 * succeeds, we assume a writable filesystem.
+	 */
+
+	varbufprintf(&tmpname, "%s%s", src->name, ".dpkg-divert.tmp");
+
+	tmpfd = creat(tmpname.buf, 0600);
+	if (tmpfd >= 0) {
+		close(tmpfd);
+		unlink(tmpname.buf);
+	} else if (errno == ENOENT) {
+		varbuf_destroy(&tmpname);
+
+		/* If the source file is not present and we are not going
+		 * to do the rename anyway there's no point in checking the
+		 * target. */
+		return false;
+	} else
+		ohshite(_("error checking '%s'"), src->name);
+
+	varbufreset(&tmpname);
+	varbufprintf(&tmpname, "%s%s", dst->name, ".dpkg-divert.tmp");
+
+	tmpfd = creat(tmpname.buf, 0600);
+	if (tmpfd >= 0) {
+		close(tmpfd);
+		unlink(tmpname.buf);
+	} else
+		ohshite(_("error checking '%s'"), dst->name);
+
+	varbuf_destroy(&tmpname);
+
+	if (src->stat_state == file_stat_valid &&
+	    dst->stat_state == file_stat_valid &&
+	    !(src->stat.st_dev == dst->stat.st_dev &&
+	      src->stat.st_ino == dst->stat.st_ino))
+		ohshit(_("rename involves overwriting `%s' with\n"
+		         "  different file `%s', not allowed"),
+		        dst->name, src->name);
+
+	return true;
+}
+
+static int
+file_copy(const char *src, const char *dst)
+{
+	int srcfd, dstfd;
+
+	srcfd = open(src, O_RDONLY);
+	if (srcfd < 0)
+		return -1;
+
+	dstfd = creat(dst, 0600);
+	if (dstfd < 0)
+		return -1;
+
+	/* FIXME: leaves a dangling destination file on error. */
+
+	fd_fd_copy(srcfd, dstfd, -1, _("file copy"));
+
+	close(srcfd);
+
+	if (fsync(dstfd))
+		return -1;
+	if (close(dstfd))
+		return -1;
+
+	file_copy_perms(src, dst);
+
+	return 0;
+}
+
+static int
+rename_mv(const char *src, const char *dst)
+{
+	struct varbuf tmpdst = VARBUF_INIT;
+
+	if (rename(src, dst) == 0)
+		return 0;
+
+	varbufprintf(&tmpdst, "%s%s", dst, ".dpkg-divert.tmp");
+
+	/* If a simple rename didn't work try an atomic copy, rename, unlink
+	 * instead. */
+	if (file_copy(src, tmpdst.buf) != 0)
+		return -1;
+
+	if (rename(tmpdst.buf, dst) != 0)
+		return -1;
+
+	varbuf_destroy(&tmpdst);
+
+	return -1;
+}
+
+static void
+file_rename(struct file *src, struct file *dst)
+{
+	if (src->stat_state == file_stat_nofile)
+		return;
+
+	if (dst->stat_state == file_stat_valid) {
+		if (unlink(src->name))
+			ohshite(_("rename: remove duplicate old link '%s'"),
+			        src->name);
+	} else {
+		if (rename_mv(src->name, dst->name))
+			ohshite(_("cannot rename '%s' to '%s'"),
+			        src->name, dst->name);
+	}
+}
+
+static const char *
+diversion_pkg_name(struct diversion *d)
+{
+	if (d->pkg == NULL)
+		return ":";
+	else
+		return d->pkg->name;
+}
+
+static const char *
+varbuf_diversion(struct varbuf *str, const char *pkgname,
+                 const char *filename, const char *divertto)
+{
+	varbufreset(str);
+
+	if (pkgname == NULL) {
+		if (divertto == NULL)
+			varbufprintf(str, _("local diversion of %s"), filename);
+		else
+			varbufprintf(str, _("local diversion of %s to %s"),
+			             filename, divertto);
+	} else {
+		if (divertto == NULL)
+			varbufprintf(str, _("diversion of %s by %s"),
+			             filename, pkgname);
+		else
+			varbufprintf(str, _("diversion of %s to %s by %s"),
+			             filename, divertto, pkgname);
+	}
+
+	return str->buf;
+}
+
+static const char *
+diversion_current(const char *filename)
+{
+	static struct varbuf str = VARBUF_INIT;
+
+	if (opt_pkgname_match_any) {
+		varbufreset(&str);
+
+		if (opt_divertto == NULL)
+			varbufprintf(&str, _("any diversion of %s"), filename);
+		else
+			varbufprintf(&str, _("any diversion of %s to %s"),
+			             filename, opt_divertto);
+	} else {
+		return varbuf_diversion(&str, opt_pkgname, filename, opt_divertto);
+	}
+
+	return str.buf;
+}
+
+static const char *
+diversion_describe(struct diversion *d)
+{
+	static struct varbuf str = VARBUF_INIT;
+	const char *pkgname;
+	const char *name_from, *name_to;
+
+	if (d->camefrom) {
+		name_from = d->camefrom->name;
+		name_to = d->camefrom->divert->useinstead->name;
+	} else {
+		name_from = d->useinstead->divert->camefrom->name;
+		name_to = d->useinstead->name;
+	}
+
+	if (d->pkg == NULL)
+		pkgname = NULL;
+	else
+		pkgname = d->pkg->name;
+
+	return varbuf_diversion(&str, pkgname, name_from, name_to);
+}
+
+static void
+divertdb_write(void)
+{
+	FILE *dbfile;
+	struct fileiterator *iter;
+	struct filenamenode *namenode;
+	struct varbuf dbname = VARBUF_INIT;
+	struct varbuf dbname_new = VARBUF_INIT;
+	struct varbuf dbname_old = VARBUF_INIT;
+
+	varbufprintf(&dbname, "%s/%s", admindir, DIVERSIONSFILE);
+	varbufprintf(&dbname_new, "%s%s", dbname.buf, NEWDBEXT);
+	varbufprintf(&dbname_old, "%s%s", dbname.buf, OLDDBEXT);
+
+	dbfile = fopen(dbname_new.buf, "w");
+	if (!dbfile)
+		ohshite(_("cannot create new %s file"), DIVERSIONSFILE);
+	chmod(dbname_new.buf, 0644);
+
+	iter = iterfilestart();
+	while ((namenode = iterfilenext(iter))) {
+		struct diversion *d = namenode->divert;
+
+		if (d == NULL || d->useinstead == NULL)
+			continue;
+
+		fprintf(dbfile, "%s\n%s\n%s\n",
+		        d->useinstead->divert->camefrom->name,
+		        d->useinstead->name,
+		        diversion_pkg_name(d));
+	}
+	iterfileend(iter);
+
+	if (fflush(dbfile))
+		ohshite(_("unable to flush file '%s'"), dbname_new.buf);
+	if (fsync(fileno(dbfile)))
+		ohshite(_("unable to sync file '%s'"), dbname_new.buf);
+	if (fclose(dbfile))
+		ohshite(_("unable to close file '%s'"), dbname_new.buf);
+
+	if (unlink(dbname_old.buf) && errno != ENOENT)
+		ohshite(_("error removing old diversions-old"));
+	if (link(dbname.buf, dbname_old.buf) && errno != ENOENT)
+		ohshite(_("error creating new diversions-old"));
+	if (rename(dbname_new.buf, dbname.buf))
+		ohshite(_("error installing new diversions"));
+
+	varbuf_destroy(&dbname);
+	varbuf_destroy(&dbname_new);
+	varbuf_destroy(&dbname_old);
+}
+
+static int
+diversion_add(const char *const *argv)
+{
+	const char *filename = argv[0];
+	struct file file_from, file_to;
+	struct diversion *contest, *altname;
+	struct filenamenode *fnn_from, *fnn_to;
+	struct pkginfo *pkg;
+
+	opt_pkgname_match_any = false;
+
+	/* Handle filename. */
+	if (!filename || argv[1])
+		badusage(_("--%s needs a single argument"), cipaction->olong);
+
+	if (filename[0] != '/')
+		badusage(_("filename \"%s\" is not absolute"), filename);
+	if (strchr(filename, '\n') != NULL)
+		badusage(_("file may not contain newlines"));
+
+	file_init(&file_from, filename);
+	file_stat(&file_from);
+
+	if (S_ISDIR(file_from.stat.st_mode))
+		badusage(_("Cannot divert directories"));
+
+	fnn_from = findnamenode(filename, 0);
+
+	/* Handle divertto. */
+	if (opt_divertto == NULL) {
+		struct varbuf str = VARBUF_INIT;
+
+		varbufprintf(&str, "%s.distrib", filename);
+		opt_divertto = varbuf_detach(&str);
+	}
+	if (opt_divertto[0] != '/')
+		badusage(_("filename \"%s\" is not absolute"), opt_divertto);
+
+	if (strcmp(filename, opt_divertto) == 0)
+		badusage(_("cannot divert file '%s' to itself"), filename);
+
+	file_init(&file_to, opt_divertto);
+
+	fnn_to = findnamenode(opt_divertto, 0);
+
+	/* Handle package name. */
+	if (opt_pkgname == NULL)
+		pkg = NULL;
+	else
+		pkg = findpackage(opt_pkgname);
+
+	/* Check we are not stomping over an existing diversion. */
+	if (fnn_from->divert || fnn_to->divert) {
+		if (fnn_to->divert && fnn_to->divert->camefrom &&
+		    strcmp(fnn_to->divert->camefrom->name, filename) == 0 &&
+		    fnn_from->divert && fnn_from->divert->useinstead &&
+		    strcmp(fnn_from->divert->useinstead->name, opt_divertto) == 0 &&
+		    fnn_from->divert->pkg == pkg) {
+			if (opt_verbose > 0)
+				printf(_("Leaving '%s'\n"),
+				       diversion_describe(fnn_from->divert));
+			exit(0);
+		}
+
+		ohshit(_("`%s' clashes with `%s'"),
+		       diversion_current(filename),
+		       fnn_from->divert ?
+		       diversion_describe(fnn_from->divert) :
+		       diversion_describe(fnn_to->divert));
+	}
+
+	/* Create new diversion. */
+	contest = nfmalloc(sizeof(*contest));
+	altname = nfmalloc(sizeof(*altname));
+
+	altname->camefrom = fnn_from;
+	altname->camefrom->divert = contest;
+	altname->useinstead = NULL;
+	altname->pkg = pkg;
+
+	contest->useinstead = fnn_to;
+	contest->useinstead->divert = altname;
+	contest->camefrom = NULL;
+	contest->pkg = pkg;
+
+	/* Update database and file system if needed. */
+	if (opt_verbose > 0)
+		printf(_("Adding '%s'\n"), diversion_describe(contest));
+	if (opt_rename)
+		opt_rename = check_rename(&file_from, &file_to);
+	if (!opt_test) {
+		divertdb_write();
+		if (opt_rename)
+			file_rename(&file_from, &file_to);
+	}
+
+	return 0;
+}
+
+static int
+diversion_remove(const char *const *argv)
+{
+	const char *filename = argv[0];
+	struct filenamenode *namenode;
+	struct diversion *contest, *altname;
+	struct file file_from, file_to;
+	struct pkginfo *pkg;
+
+	if (!filename || argv[1])
+		badusage(_("--%s needs a single argument"), cipaction->olong);
+
+	namenode = findnamenode(filename, fnn_nonew);
+
+	if (namenode == NULL || namenode->divert == NULL ||
+	    namenode->divert->useinstead == NULL) {
+		if (opt_verbose > 0)
+			printf(_("No diversion '%s', none removed.\n"),
+			       diversion_current(filename));
+		return 0;
+	}
+
+	if (opt_pkgname == NULL)
+		pkg = NULL;
+	else
+		pkg = findpackage(opt_pkgname);
+
+	contest = namenode->divert;
+	altname = contest->useinstead->divert;
+
+	if (opt_divertto != NULL &&
+	    strcmp(opt_divertto, contest->useinstead->name) != 0)
+		ohshit(_("mismatch on divert-to\n"
+		         "  when removing `%s'\n"
+		         "  found `%s'"),
+		       diversion_current(filename),
+		       diversion_describe(contest));
+
+	if (!opt_pkgname_match_any && pkg != contest->pkg)
+		ohshit(_("mismatch on package\n"
+		         "  when removing `%s'\n"
+		         "  found `%s'"),
+		       diversion_current(filename),
+		       diversion_describe(contest));
+
+	if (opt_verbose > 0)
+		printf(_("Removing '%s'\n"), diversion_describe(contest));
+
+	file_init(&file_from, altname->camefrom->name);
+	file_init(&file_to, contest->useinstead->name);
+
+	/* Remove entries from database. */
+	contest->useinstead->divert = NULL;
+	altname->camefrom->divert = NULL;
+
+	if (opt_rename)
+		opt_rename = check_rename(&file_to, &file_from);
+	if (opt_rename && !opt_test)
+		file_rename(&file_to, &file_from);
+
+	if (!opt_test)
+		divertdb_write();
+
+	return 0;
+}
+
+static int
+diversion_list(const char *const *argv)
+{
+	struct fileiterator *iter;
+	struct filenamenode *namenode;
+	struct glob_node *glob_list = NULL;
+	const char *pattern;
+
+	while ((pattern = *argv++))
+		glob_list_prepend(&glob_list, m_strdup(pattern));
+
+	if (glob_list == NULL)
+		glob_list_prepend(&glob_list, m_strdup("*"));
+
+	iter = iterfilestart();
+	while ((namenode = iterfilenext(iter))) {
+		struct glob_node *g;
+		struct diversion *contest = namenode->divert;
+		struct diversion *altname;
+		const char *pkg_name;
+
+		if (contest->useinstead == NULL)
+			continue;
+
+		altname = contest->useinstead->divert;
+
+		pkg_name = diversion_pkg_name(contest);
+
+		for (g = glob_list; g; g = g->next) {
+			if (fnmatch(g->pattern, pkg_name, 0) == 0 ||
+			    fnmatch(g->pattern, contest->useinstead->name, 0) == 0 ||
+			    fnmatch(g->pattern, altname->camefrom->name, 0) == 0) {
+				printf("%s\n", diversion_describe(contest));
+				break;
+			}
+		}
+	}
+	iterfileend(iter);
+
+	glob_list_free(glob_list);
+
+	return 0;
+}
+
+static int
+diversion_truename(const char *const *argv)
+{
+	const char *filename = argv[0];
+	struct filenamenode *namenode;
+
+	if (!filename || argv[1])
+		badusage(_("--%s needs a single argument"), cipaction->olong);
+
+	namenode = findnamenode(filename, fnn_nonew);
+
+	/* Print the given name if file is not diverted. */
+	if (namenode && namenode->divert->useinstead)
+		printf("%s\n", namenode->divert->useinstead->name);
+	else
+		printf("%s\n", filename);
+
+	return 0;
+}
+
+static int
+diversion_listpackage(const char *const *argv)
+{
+	const char *filename = argv[0];
+	struct filenamenode *namenode;
+
+	if (!filename || argv[1])
+		badusage(_("--%s needs a single argument"), cipaction->olong);
+
+	namenode = findnamenode(filename, fnn_nonew);
+
+	/* Print nothing if file is not diverted. */
+	if (namenode == NULL)
+		return 0;
+
+	if (namenode->divert->pkg == NULL)
+		/* Indicate package is local using something not in package
+		 * namespace. */
+		printf("LOCAL\n");
+	else
+		printf("%s\n", namenode->divert->pkg->name);
+
+	return 0;
+}
+
+static inline int
+option_short(int c)
+{
+	return c ? c : '\b';
+}
+
+static void
+setaction(const struct cmdinfo *cip, const char *value)
+{
+	if (cipaction)
+		badusage(_("conflicting actions -%c (--%s) and -%c (--%s)"),
+		         option_short(cip->oshort), cip->olong,
+		         option_short(cipaction->oshort), cipaction->olong);
+	cipaction = cip;
+}
+
+static void
+setpackage(const struct cmdinfo *cip, const char *value)
+{
+	opt_pkgname_match_any = false;
+
+	/* If value is NULL we are being called from --local. */
+	opt_pkgname = value;
+
+	if (opt_pkgname && strchr(opt_pkgname, '\n') != NULL)
+		badusage(_("package may not contain newlines"));
+}
+
+static void
+setdivertto(const struct cmdinfo *cip, const char *value)
+{
+	opt_divertto = value;
+
+	if (strchr(opt_divertto, '\n') != NULL)
+		badusage(_("divert-to may not contain newlines"));
+}
+
+#define ACTION(longopt, shortopt, code, function) \
+ { longopt, shortopt, 0, 0, 0, setaction, code, 0, (voidfnp)function }
+
+static const struct cmdinfo cmdinfo_add =
+	ACTION("add",         0, 0, diversion_add);
+
+static const struct cmdinfo cmdinfos[] = {
+	ACTION("add",         0, 0, diversion_add),
+	ACTION("remove",      0, 0, diversion_remove),
+	ACTION("list",        0, 0, diversion_list),
+	ACTION("listpackage", 0, 0, diversion_listpackage),
+	ACTION("truename",    0, 0, diversion_truename),
+
+	{ "admindir",   0,   1,  NULL,         &admindir, NULL          },
+	{ "divert",     0,   1,  NULL,         NULL,      setdivertto   },
+	{ "package",    0,   1,  NULL,         NULL,      setpackage    },
+	{ "local",      0,   0,  NULL,         NULL,      setpackage    },
+	{ "quiet",      0,   0,  &opt_verbose, NULL,      NULL, 0       },
+	{ "rename",     0,   0,  &opt_rename,  NULL,      NULL, 1       },
+	{ "test",       0,   0,  &opt_test,    NULL,      NULL, 1       },
+	{ "help",       0,   0,  NULL,         NULL,      usage         },
+	{ "version",    0,   0,  NULL,         NULL,      printversion  },
+	{  NULL,        0                                               }
+};
+
+int
+main(int argc, const char * const *argv)
+{
+	jmp_buf ejbuf;
+	int (*actionfunction)(const char *const *argv);
+	int ret;
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+
+	standard_startup(&ejbuf);
+	myopt(&argv, cmdinfos);
+
+	if (!cipaction)
+		cipaction = &cmdinfo_add;
+
+	actionfunction = (int (*)(const char *const *))cipaction->farg;
+
+	setvbuf(stdout, NULL, _IONBF, 0);
+
+	filesdbinit();
+	ensure_diversions();
+
+	ret = actionfunction(argv);
+
+	standard_shutdown();
+
+	return ret;
+}