* Fix the garbage collector.

scripts/nix-collect-garbage.in

@@ -17,9 +17,24 @@ foreach my $arg (@ARGV) {
     else { die "unknown argument `$arg'" };
 }
 
+opendir(DIR, $linkdir) or die "cannot open directory $linkdir: $!";
+my @links = readdir DIR or die "cannot read directory $linkdir: $!";
+closedir DIR;
+
+my @roots;
+foreach my $link (@links) {
+    $link = $linkdir . "/" . $link;
+    next if (!($link =~ /.id$/));
+    open ROOT, "<$link" or die "cannot open $link: $!";
+    my $root = <ROOT>;
+    chomp $root;
+    close ROOT;
+    push @roots, $root;
+}
+
 my $extraarg = "";
 if ($keepsuccessors) { $extraarg = "--include-successors"; };
-my $pid = open2(\*READ, \*WRITE, "nix --query --requisites $extraarg \$(cat $linkdir/*.id)") 
+my $pid = open2(\*READ, \*WRITE, "nix-store --query --requisites $extraarg @roots") 
     or die "determining live paths";
 close WRITE;
 while (<READ>) {
@@ -34,8 +49,8 @@ $? == 0 or die "determining live paths";
 
 exit 0 if ($invert);
 
-opendir(DIR, $storedir) or die "cannot opendir $storedir: $!";
+opendir(DIR, $storedir) or die "cannot open directory $storedir: $!";
-my @names = readdir(DIR);
+my @names = readdir DIR;
 closedir DIR;
 
 foreach my $name (@names) {

src/libstore/store.cc

@@ -1,9 +1,6 @@
 #include <iostream>
 
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <sys/wait.h>
-#include <fcntl.h>
 #include <unistd.h>
 
 #include "store.hh"
@@ -307,11 +304,7 @@ void addTextToStore(const Path & dstPath, const string & s)
         PathLocks outputLock(lockPaths);
 
         if (!isValidPath(dstPath)) {
-
+            writeStringToFile(dstPath, s);
-            AutoCloseFD fd = open(dstPath.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666);
-            if (fd == -1) throw SysError(format("creating store file `%1%'") % dstPath);
-
-            writeFull(fd, (unsigned char *) s.c_str(), s.size());
 
             Transaction txn(nixDB);
             registerValidPath(txn, dstPath);

src/libutil/util.cc

@@ -6,6 +6,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <dirent.h>
+#include <fcntl.h>
 
 #include "util.hh"
 
@@ -192,6 +193,16 @@ Path createTempDir()
 }
 
 
+void writeStringToFile(const Path & path, const string & s)
+{
+    AutoCloseFD fd = open(path.c_str(),
+        O_CREAT | O_EXCL | O_WRONLY, 0666);
+    if (fd == -1)
+        throw SysError(format("creating file `%1%'") % path);
+    writeFull(fd, (unsigned char *) s.c_str(), s.size());
+}
+
+
 Verbosity verbosity = lvlError;
 
 static int nestingLevel = 0;

src/libutil/util.hh

@@ -87,6 +87,11 @@ void makePathReadOnly(const Path & path);
 /* Create a temporary directory. */
 Path createTempDir();
 
+/* Create a file and write the given text to it.  The file is written
+   in binary mode (i.e., no end-of-line conversions).  The path should
+   not already exist. */
+void writeStringToFile(const Path & path, const string & s);
+
 
 /* Messages. */
 

src/nix-env/main.cc

@@ -139,6 +139,8 @@ Path createLink(Path outPath, Path drvPath)
         num++;
     }
 
+    writeStringToFile(linkPath + "-src.id", drvPath);
+
     return linkPath;
 }
 
@@ -290,7 +292,7 @@ void uninstallDerivations(EvalState & state, Strings drvNames)
             installedDrvs.erase(j->second);
     }
 
-   createUserEnv(state, installedDrvs);
+    createUserEnv(state, installedDrvs);
 }