contrib/hooks/setgitperms.perl

   1 #!/usr/bin/perl
   2 #
   3 # Copyright (c) 2006 Josh England
   4 #
   5 # This script can be used to save/restore full permissions and ownership data
   6 # within a git working tree.
   7 #
   8 # To save permissions/ownership data, place this script in your .git/hooks
   9 # directory and enable a `pre-commit` hook with the following lines:
  10 #      #!/bin/sh
  11 #     SUBDIRECTORY_OK=1 . git-sh-setup
  12 #     $GIT_DIR/hooks/setgitperms.perl -r
  13 #
  14 # To restore permissions/ownership data, place this script in your .git/hooks
  15 # directory and enable a `post-merge` and `post-checkout` hook with the
  16 # following lines:
  17 #      #!/bin/sh
  18 #     SUBDIRECTORY_OK=1 . git-sh-setup
  19 #     $GIT_DIR/hooks/setgitperms.perl -w
  20 #
  21 use strict;
  22 use Getopt::Long;
  23 use File::Find;
  24 use File::Basename;
  25
  26 my $usage =
  27 "usage: setgitperms.perl [OPTION]... <--read|--write>
  28 This program uses a file `.gitmeta` to store/restore permissions and uid/gid
  29 info for all files/dirs tracked by git in the repository.
  30
  31 ---------------------------------Read Mode-------------------------------------
  32 -r,  --read         Reads perms/etc from working dir into a .gitmeta file
  33 -s,  --stdout       Output to stdout instead of .gitmeta
  34 -d,  --diff         Show unified diff of perms file (XOR with --stdout)
  35
  36 ---------------------------------Write Mode------------------------------------
  37 -w,  --write        Modify perms/etc in working dir to match the .gitmeta file
  38 -v,  --verbose      Be verbose
  39
  40 \n";
  41
  42 my ($stdout, $showdiff, $verbose, $read_mode, $write_mode);
  43
  44 if ((@ARGV < 0) || !GetOptions(
  45                                "stdout",         \$stdout,
  46                                "diff",           \$showdiff,
  47                                "read",           \$read_mode,
  48                                "write",          \$write_mode,
  49                                "verbose",        \$verbose,
  50                               )) { die $usage; }
  51 die $usage unless ($read_mode xor $write_mode);
  52
  53 my $topdir = `git rev-parse --show-cdup` or die "\n"; chomp $topdir;
  54 my $gitdir = $topdir . '.git';
  55 my $gitmeta = $topdir . '.gitmeta';
  56
  57 if ($write_mode) {
  58     # Update the working dir permissions/ownership based on data from .gitmeta
  59     open (IN, "<$gitmeta") or die "Could not open $gitmeta for reading: $!\n";
  60     while (defined ($_ = <IN>)) {
  61         chomp;
  62         if (/^(.*)  mode=(\S+)\s+uid=(\d+)\s+gid=(\d+)/) {
  63             # Compare recorded perms to actual perms in the working dir
  64             my ($path, $mode, $uid, $gid) = ($1, $2, $3, $4);
  65             my $fullpath = $topdir . $path;
  66             my (undef,undef,$wmode,undef,$wuid,$wgid) = lstat($fullpath);
  67             $wmode = sprintf "%04o", $wmode & 07777;
  68             if ($mode ne $wmode) {
  69                 $verbose && print "Updating permissions on $path: old=$wmode, new=$mode\n";
  70                 chmod oct($mode), $fullpath;
  71             }
  72             if ($uid != $wuid || $gid != $wgid) {
  73                 if ($verbose) {
  74                     # Print out user/group names instead of uid/gid
  75                     my $pwname  = getpwuid($uid);
  76                     my $grpname  = getgrgid($gid);
  77                     my $wpwname  = getpwuid($wuid);
  78                     my $wgrpname  = getgrgid($wgid);
  79                     $pwname = $uid if !defined $pwname;
  80                     $grpname = $gid if !defined $grpname;
  81                     $wpwname = $wuid if !defined $wpwname;
  82                     $wgrpname = $wgid if !defined $wgrpname;
  83
  84                     print "Updating uid/gid on $path: old=$wpwname/$wgrpname, new=$pwname/$grpname\n";
  85                 }
  86                 chown $uid, $gid, $fullpath;
  87             }
  88         }
  89         else {
  90             warn "Invalid input format in $gitmeta:\n\t$_\n";
  91         }
  92     }
  93     close IN;
  94 }
  95 elsif ($read_mode) {
  96     # Handle merge conflicts in the .gitperms file
  97     if (-e "$gitdir/MERGE_MSG") {
  98         if (`grep ====== $gitmeta`) {
  99             # Conflict not resolved -- abort the commit
 100             print "PERMISSIONS/OWNERSHIP CONFLICT\n";
 101             print "    Resolve the conflict in the $gitmeta file and then run\n";
 102             print "    `.git/hooks/setgitperms.perl --write` to reconcile.\n";
 103             exit 1;
 104         }
 105         elsif (`grep $gitmeta $gitdir/MERGE_MSG`) {
 106             # A conflict in .gitmeta has been manually resolved. Verify that
 107             # the working dir perms matches the current .gitmeta perms for
 108             # each file/dir that conflicted.
 109             # This is here because a `setgitperms.perl --write` was not
 110             # performed due to a merge conflict, so permissions/ownership
 111             # may not be consistent with the manually merged .gitmeta file.
 112             my @conflict_diff = `git show \$(cat $gitdir/MERGE_HEAD)`;
 113             my @conflict_files;
 114             my $metadiff = 0;
 115
 116             # Build a list of files that conflicted from the .gitmeta diff
 117             foreach my $line (@conflict_diff) {
 118                 if ($line =~ m|^diff --git a/$gitmeta b/$gitmeta|) {
 119                     $metadiff = 1;
 120                 }
 121                 elsif ($line =~ /^diff --git/) {
 122                     $metadiff = 0;
 123                 }
 124                 elsif ($metadiff && $line =~ /^\+(.*)  mode=/) {
 125                     push @conflict_files, $1;
 126                 }
 127             }
 128
 129             # Verify that each conflict file now has permissions consistent
 130             # with the .gitmeta file
 131             foreach my $file (@conflict_files) {
 132                 my $absfile = $topdir . $file;
 133                 my $gm_entry = `grep "^$file  mode=" $gitmeta`;
 134                 if ($gm_entry =~ /mode=(\d+)  uid=(\d+)  gid=(\d+)/) {
 135                     my ($gm_mode, $gm_uid, $gm_gid) = ($1, $2, $3);
 136                     my (undef,undef,$mode,undef,$uid,$gid) = lstat("$absfile");
 137                     $mode = sprintf("%04o", $mode & 07777);
 138                     if (($gm_mode ne $mode) || ($gm_uid != $uid)
 139                         || ($gm_gid != $gid)) {
 140                         print "PERMISSIONS/OWNERSHIP CONFLICT\n";
 141                         print "    Mismatch found for file: $file\n";
 142                         print "    Run `.git/hooks/setgitperms.perl --write` to reconcile.\n";
 143                         exit 1;
 144                     }
 145                 }
 146                 else {
 147                     print "Warning! Permissions/ownership no longer being tracked for file: $file\n";
 148                 }
 149             }
 150         }
 151     }
 152
 153     # No merge conflicts -- write out perms/ownership data to .gitmeta file
 154     unless ($stdout) {
 155         open (OUT, ">$gitmeta.tmp") or die "Could not open $gitmeta.tmp for writing: $!\n";
 156     }
 157
 158     my @files = `git ls-files`;
 159     my %dirs;
 160
 161     foreach my $path (@files) {
 162         chomp $path;
 163         # We have to manually add stats for parent directories
 164         my $parent = dirname($path);
 165         while (!exists $dirs{$parent}) {
 166             $dirs{$parent} = 1;
 167             next if $parent eq '.';
 168             printstats($parent);
 169             $parent = dirname($parent);
 170         }
 171         # Now the git-tracked file
 172         printstats($path);
 173     }
 174
 175     # diff the temporary metadata file to see if anything has changed
 176     # If no metadata has changed, don't overwrite the real file
 177     # This is just so `git commit -a` doesn't try to commit a bogus update
 178     unless ($stdout) {
 179         if (! -e $gitmeta) {
 180             rename "$gitmeta.tmp", $gitmeta;
 181         }
 182         else {
 183             my $diff = `diff -U 0 $gitmeta $gitmeta.tmp`;
 184             if ($diff ne '') {
 185                 rename "$gitmeta.tmp", $gitmeta;
 186             }
 187             else {
 188                 unlink "$gitmeta.tmp";
 189             }
 190             if ($showdiff) {
 191                 print $diff;
 192             }
 193         }
 194         close OUT;
 195     }
 196     # Make sure the .gitmeta file is tracked
 197     system("git add $gitmeta");
 198 }
 199
 200
 201 sub printstats {
 202     my $path = $_[0];
 203     $path =~ s/@/\@/g;
 204     my (undef,undef,$mode,undef,$uid,$gid) = lstat($path);
 205     $path =~ s/%/\%/g;
 206     if ($stdout) {
 207         print $path;
 208         printf "  mode=%04o  uid=$uid  gid=$gid\n", $mode & 07777;
 209     }
 210     else {
 211         print OUT $path;
 212         printf OUT "  mode=%04o  uid=$uid  gid=$gid\n", $mode & 07777;
 213     }
 214 }