git-cache-proxy: Use open-coded fork/exec for git gc

This allows us to handle ENOENT from chdir specially.  We want to
tolerate this, because it can happen if the previous lockholder
cleaned it all up.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/scripts/git-cache-proxy b/scripts/git-cache-proxy
index 636ebfecb2adb51e0f0296ccd7a334c3e51ea89e..ec5ff7f2e81aa9c4fd67069e537479e812f5f60c 100755 (executable)
--- a/scripts/git-cache-proxy
+++ b/scripts/git-cache-proxy
@@ -447,12 +447,19 @@ sub housekeeping () {
            $mode_action = sub {
                my $gclog = "$subdir/gc.log";
                unlink $gclog or $!==ENOENT or hkfail "remove $gclog: $!";
-               my $r = system qw(sh -ec),
-                   'cd "$1"; shift; exec "$@"', 'x', "$subdir\\.git",
-                   qw(git gc --quiet);
-               if ($r) {
+               my $child = fork // hkfail "fork (for $subdir): $!";
+               if (!$child) {
+                   if (!chdir "$subdir\\.git") {
+                       exit 0 if $!==ENOENT;
+                       die "for gc: chdir $subdir: $!\n";
+                   }
+                   exec qw(git gc --quiet);
+                   die "exec git gc (for $subdir): $!\n";
+               }
+               waitpid($child, 0) == $child or hkfail "waitpid failed! $!";
+               if ($?) {
                    logm 'err',
-                       "housekeeping: subdirs $subdir: gc failed (status $r)";
+ "housekeeping: subdirs $subdir: gc failed (wait status $?)";
                } else {
                    update_gcstamp("$subdir\\.git");
                    logm 'debug',