Revert "Prevent config.h from being clobbered"

This reverts commit 28bba8c44f484eae38e8a15dcec73cfa999156f6.

27 files changed, 277 insertions, 165 deletions

diff --git a/corepkgs/fetchurl.nix b/corepkgs/fetchurl.nix
index 4a0ae827995d..39b9dd5082e3 100644
--- a/corepkgs/fetchurl.nix
+++ b/corepkgs/fetchurl.nix
@@ -1,6 +1,6 @@
 with import <nix/config.nix>;
 
-{system ? builtins.currentSystem, url, outputHash ? "", outputHashAlgo ? "", md5 ? "", sha1 ? "", sha256 ? ""}:
+{system ? builtins.currentSystem, url, outputHash ? "", outputHashAlgo ? "", md5 ? "", sha1 ? "", sha256 ? "", executable ? false}:
 
 assert (outputHash != "" && outputHashAlgo != "")
     || md5 != "" || sha1 != "" || sha256 != "";
@@ -8,10 +8,10 @@ assert (outputHash != "" && outputHashAlgo != "")
 let
 
   builder = builtins.toFile "fetchurl.sh"
-    ''
+    (''
       echo "downloading $url into $out"
       ${curl} --fail --location --max-redirs 20 --insecure "$url" > "$out"
-    '';
+    '' + (if executable then "${coreutils}/chmod +x $out" else ""));
 
 in
     
@@ -25,6 +25,7 @@ derivation {
       if sha256 != "" then "sha256" else if sha1 != "" then "sha1" else "md5";
   outputHash = if outputHash != "" then outputHash else
       if sha256 != "" then sha256 else if sha1 != "" then sha1 else md5;
+  outputHashMode = if executable then "recursive" else "flat";
   
   inherit system url;
 
diff --git a/doc/dev/release-procedures.txt b/doc/dev/release-procedures.txt
deleted file mode 100644
index 1e95a9ee9aca..000000000000
--- a/doc/dev/release-procedures.txt
+++ /dev/null
@@ -1,33 +0,0 @@
-To produce a `stable' release from the trunk:
-
--1. Update the release notes; make sure that the release date is
-    correct.
-
-0. Make sure that the trunk builds in the release supervisor.
-
-1. Branch the trunk, e.g., `svn cp .../trunk
-   .../branches/0.5-release'.
-
-2. Switch to the branch, e.g., `svn switch .../branches/0.5-release'.
-
-3. In `configure.ac', change `STABLE=0' into `STABLE=1' and commit.
-
-4. In the release supervisor, add a one-time job to build
-   `.../branches/0.5-release'.
-
-5. Make sure that the release succeeds.
-
-6. Move the branch to a tag, e.g., `svn mv .../branches/0.5-release
-   .../tags/0.5'.
-
-   Note that the branch should not be used for maintenance; it should
-   be deleted after the release has been created.  A maintenance
-   branch (e.g., `.../branches/0.5') should be created from the
-   original revision of the trunk (since maintenance releases should
-   also be tested first; hence, we cannot have `STABLE=1').  The same
-   procedure can then be followed to produce maintenance releases;
-   just substitute `.../branches/VERSION' for the trunk.
-
-7. Switch back to the trunk.
-
-8. Bump the version number in `configure.ac' (in AC_INIT).
diff --git a/doc/manual/builtins.xml b/doc/manual/builtins.xml
index 9f5f4438ce55..b75f58e21f1b 100644
--- a/doc/manual/builtins.xml
+++ b/doc/manual/builtins.xml
@@ -302,6 +302,18 @@ stdenv.mkDerivation {
   </varlistentry>
 
 
+  <varlistentry><term><function>builtins.hashString</function>
+  <replaceable>type</replaceable> <replaceable>s</replaceable></term>
+
+    <listitem><para>Return a base-16 representation of the
+    cryptographic hash of string <replaceable>s</replaceable>.  The
+    hash algorithm specified by <replaceable>type</replaceable> must
+    be one of <literal>"md5"</literal>, <literal>"sha1"</literal> or
+    <literal>"sha256"</literal>.</para></listitem>
+
+  </varlistentry>
+
+
   <varlistentry><term><function>builtins.head</function>
   <replaceable>list</replaceable></term>
 
diff --git a/doc/manual/opt-common.xml b/doc/manual/opt-common.xml
index 72971bd6a7d5..329345773dd8 100644
--- a/doc/manual/opt-common.xml
+++ b/doc/manual/opt-common.xml
@@ -343,10 +343,11 @@
 
 <varlistentry><term><option>-I</option> <replaceable>path</replaceable></term>
   
-  <listitem><para>Add a path to the Nix expression search path.  See
-  the <envar>NIX_PATH</envar> environment variable for details.  Paths
-  added through <option>-I</option> take precedence over
-  <envar>NIX_PATH</envar>.</para></listitem>
+  <listitem><para>Add a path to the Nix expression search path.  This
+  option may be given multiple times.  See the <envar>NIX_PATH</envar>
+  environment variable for information on the semantics of the Nix
+  search path.  Paths added through <option>-I</option> take
+  precedence over <envar>NIX_PATH</envar>.</para></listitem>
   
 </varlistentry>
 
diff --git a/doc/manual/release-notes.xml b/doc/manual/release-notes.xml
index e7e9bf3c5b43..a078be83d5ab 100644
--- a/doc/manual/release-notes.xml
+++ b/doc/manual/release-notes.xml
@@ -8,6 +8,63 @@
 
 <!--==================================================================-->
 
+<section xml:id="ssec-relnotes-1.5.1"><title>Release 1.5.1 (February 28, 2013)</title>
+
+<para>The bug fix to the bug fix had a bug itself, of course.  But
+this time it will work for sure!</para>
+
+</section>
+
+
+<!--==================================================================-->
+
+<section xml:id="ssec-relnotes-1.5"><title>Release 1.5 (February 27, 2013)</title>
+
+<para>This is a brown paper bag release to fix a regression introduced
+by the hard link security fix in 1.4.</para>
+
+</section>
+
+
+<!--==================================================================-->
+
+<section xml:id="ssec-relnotes-1.4"><title>Release 1.4 (February 26, 2013)</title>
+
+<para>This release fixes a security bug in multi-user operation.  It
+was possible for derivations to cause the mode of files outside of the
+Nix store to be changed to 444 (read-only but world-readable) by
+creating hard links to those files (<link
+xlink:href="https://github.com/NixOS/nix/commit/5526a282b5b44e9296e61e07d7d2626a79141ac4">details</link>).</para>
+
+<para>There are also the following improvements:</para>
+
+<itemizedlist>
+
+  <listitem><para>New built-in function:
+  <function>builtins.hashString</function>.</para></listitem>
+
+  <listitem><para>Build logs are now stored in
+  <filename>/nix/var/log/nix/drvs/<replaceable>XX</replaceable>/</filename>,
+  where <replaceable>XX</replaceable> is the first two characters of
+  the derivation.  This is useful on machines that keep a lot of build
+  logs (such as Hydra servers).</para></listitem>
+
+  <listitem><para>The function <function>corepkgs/fetchurl</function>
+  can now make the downloaded file executable.  This will allow
+  getting rid of all bootstrap binaries in the Nixpkgs source
+  tree.</para></listitem>
+
+  <listitem><para>Language change: The expression <literal>"${./path}
+  ..."</literal> now evaluates to a string instead of a
+  path.</para></listitem>
+
+</itemizedlist>
+
+</section>
+
+
+<!--==================================================================-->
+
 <section xml:id="ssec-relnotes-1.3"><title>Release 1.3 (January 4, 2013)</title>
 
 <para>This is primarily a bug fix release.  When this version is first
diff --git a/perl/lib/Nix/Store.xs b/perl/lib/Nix/Store.xs
index 00311aa8f3bf..8154bcbb0f4b 100644
--- a/perl/lib/Nix/Store.xs
+++ b/perl/lib/Nix/Store.xs
@@ -15,7 +15,7 @@
 using namespace nix;
 
 
-void doInit() 
+void doInit()
 {
     if (!store) {
         try {
@@ -237,32 +237,35 @@ SV * derivationFromPath(char * drvPath)
             doInit();
             Derivation drv = derivationFromPath(*store, drvPath);
             hash = newHV();
-            
-            /* TODO: handle drv.outputs */
-            
+
+            HV * outputs = newHV();
+            for (DerivationOutputs::iterator i = drv.outputs.begin(); i != drv.outputs.end(); ++i)
+                hv_store(outputs, i->first.c_str(), i->first.size(), newSVpv(i->second.path.c_str(), 0), 0);
+            hv_stores(hash, "outputs", newRV((SV *) outputs));
+
             AV * inputDrvs = newAV();
             for (DerivationInputs::iterator i = drv.inputDrvs.begin(); i != drv.inputDrvs.end(); ++i)
                 av_push(inputDrvs, newSVpv(i->first.c_str(), 0)); // !!! ignores i->second
             hv_stores(hash, "inputDrvs", newRV((SV *) inputDrvs));
-            
+
             AV * inputSrcs = newAV();
             for (PathSet::iterator i = drv.inputSrcs.begin(); i != drv.inputSrcs.end(); ++i)
                 av_push(inputSrcs, newSVpv(i->c_str(), 0));
             hv_stores(hash, "inputSrcs", newRV((SV *) inputSrcs));
-            
+
             hv_stores(hash, "platform", newSVpv(drv.platform.c_str(), 0));
             hv_stores(hash, "builder", newSVpv(drv.builder.c_str(), 0));
-            
+
             AV * args = newAV();
             for (Strings::iterator i = drv.args.begin(); i != drv.args.end(); ++i)
                 av_push(args, newSVpv(i->c_str(), 0));
             hv_stores(hash, "args", newRV((SV *) args));
-            
+
             HV * env = newHV();
             for (StringPairs::iterator i = drv.env.begin(); i != drv.env.end(); ++i)
                 hv_store(env, i->first.c_str(), i->first.size(), newSVpv(i->second.c_str(), 0), 0);
             hv_stores(hash, "env", newRV((SV *) env));
-            
+
             RETVAL = newRV_noinc((SV *)hash);
         } catch (Error & e) {
             croak(e.what());
diff --git a/scripts/build-remote.pl.in b/scripts/build-remote.pl.in
index 458d31be92f8..dddd9e959e27 100755
--- a/scripts/build-remote.pl.in
+++ b/scripts/build-remote.pl.in
@@ -258,8 +258,9 @@ close UPLOADLOCK;
 
 # Perform the build.
 my $buildFlags =
-    "--max-silent-time $maxSilentTime --option build-timeout $buildTimeout "
-    . "--fallback --add-root $rootsDir/\$PPID.out --option verbosity 0";
+    "--max-silent-time $maxSilentTime --option build-timeout $buildTimeout"
+    . " --fallback --add-root $rootsDir/\$PPID.out --quiet"
+    . " --option build-keep-log false";
 
 # We let the remote side kill its process group when the connection is
 # closed unexpectedly.  This is necessary to ensure that no processes
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 676dd3ac461a..a1613a4205b4 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -966,7 +966,7 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
            since paths are copied when they are used in a derivation),
            and none of the strings are allowed to have contexts. */
         if (first) {
-            isPath = vStr.type == tPath;
+            isPath = !forceString && vStr.type == tPath;
             first = false;
         }
 
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index bc6c3287c79d..86a7bfd506a0 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -277,8 +277,10 @@ MakeBinOp(OpConcatLists, "++")
 
 struct ExprConcatStrings : Expr
 {
+    bool forceString;
     vector<Expr *> * es;
-    ExprConcatStrings(vector<Expr *> * es) : es(es) { };
+    ExprConcatStrings(bool forceString, vector<Expr *> * es)
+        : forceString(forceString), es(es) { };
     COMMON_METHODS
 };
 
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 1819da5e1caa..66edfb548b32 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -203,7 +203,7 @@ static Expr * stripIndentation(SymbolTable & symbols, vector<Expr *> & es)
         es2->push_back(new ExprString(symbols.create(s2)));
     }
 
-    return es2->size() == 1 ? (*es2)[0] : new ExprConcatStrings(es2);
+    return es2->size() == 1 ? (*es2)[0] : new ExprConcatStrings(true, es2);
 }
 
 
@@ -318,7 +318,7 @@ expr_op
     { vector<Expr *> * l = new vector<Expr *>;
       l->push_back($1);
       l->push_back($3);
-      $$ = new ExprConcatStrings(l);
+      $$ = new ExprConcatStrings(false, l);
     }
   | expr_op CONCAT expr_op { $$ = new ExprOpConcatLists($1, $3); }
   | expr_app
@@ -349,7 +349,7 @@ expr_simple
       /* For efficiency, and to simplify parse trees a bit. */
       if ($2->empty()) $$ = new ExprString(data->symbols.create(""));
       else if ($2->size() == 1) $$ = $2->front();
-      else $$ = new ExprConcatStrings($2);
+      else $$ = new ExprConcatStrings(true, $2);
   }
   | IND_STRING_OPEN ind_string_parts IND_STRING_CLOSE {
       $$ = stripIndentation(data->symbols, *$2);
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index f8f893d69683..f66b24b7708a 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1107,6 +1107,21 @@ static void prim_unsafeDiscardOutputDependency(EvalState & state, Value * * args
 }
 
 
+/* Return the cryptographic hash of a string in base-16. */
+static void prim_hashString(EvalState & state, Value * * args, Value & v)
+{
+    string type = state.forceStringNoCtx(*args[0]);
+    HashType ht = parseHashType(type);
+    if (ht == htUnknown)
+      throw Error(format("unknown hash type `%1%'") % type);
+
+    PathSet context; // discarded
+    string s = state.forceString(*args[1], context);
+
+    mkString(v, printHash(hashString(ht, s)), context);
+};
+
+
 /*************************************************************
  * Versions
  *************************************************************/
@@ -1234,6 +1249,7 @@ void EvalState::createBaseEnv()
     addPrimOp("__stringLength", 1, prim_stringLength);
     addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
     addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
+    addPrimOp("__hashString", 2, prim_hashString);
 
     // Versions
     addPrimOp("__parseDrvName", 1, prim_parseDrvName);
diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index e869ef0379ad..4796629dc48c 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -168,11 +168,10 @@ static void initAndRun(int argc, char * * argv)
     remaining.clear();
 
     /* Process default options. */
-    int verbosityDelta = lvlInfo;
     for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
         string arg = *i;
-        if (arg == "--verbose" || arg == "-v") verbosityDelta++;
-        else if (arg == "--quiet") verbosityDelta--;
+        if (arg == "--verbose" || arg == "-v") verbosity = (Verbosity) (verbosity + 1);
+        else if (arg == "--quiet") verbosity = verbosity > lvlError ? (Verbosity) (verbosity - 1) : lvlError;
         else if (arg == "--log-type") {
             string s = getArg(arg, i, args.end());
             setLogType(s);
@@ -219,8 +218,6 @@ static void initAndRun(int argc, char * * argv)
         else remaining.push_back(arg);
     }
 
-    verbosity = (Verbosity) (verbosityDelta < 0 ? 0 : verbosityDelta);
-
     settings.update();
 
     run(remaining);
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 75802c324ef9..73223bc1ad84 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -43,6 +43,12 @@
 #include <sched.h>
 #endif
 
+/* In GNU libc 2.11, <sys/mount.h> does not define `MS_PRIVATE', but
+   <linux/fs.h> does.  */
+#if !defined MS_PRIVATE && defined HAVE_LINUX_FS_H
+#include <linux/fs.h>
+#endif
+
 #define CHROOT_ENABLED HAVE_CHROOT && HAVE_UNSHARE && HAVE_SYS_MOUNT_H && defined(MS_BIND) && defined(MS_PRIVATE) && defined(CLONE_NEWNS)
 
 #if CHROOT_ENABLED
@@ -2281,7 +2287,7 @@ void DerivationGoal::computeClosure()
         }
 
         /* Get rid of all weird permissions. */
-        canonicalisePathMetaData(path);
+        canonicalisePathMetaData(path, buildUser.enabled() ? buildUser.getUID() : -1);
 
         /* For this output path, find the references to other paths
            contained in it.  Compute the SHA-256 NAR hash at the same
@@ -2343,13 +2349,15 @@ Path DerivationGoal::openLogFile()
 {
     if (!settings.keepLog) return "";
 
+    string baseName = baseNameOf(drvPath);
+
     /* Create a log file. */
-    Path dir = (format("%1%/%2%") % settings.nixLogDir % drvsLogDir).str();
+    Path dir = (format("%1%/%2%/%3%/") % settings.nixLogDir % drvsLogDir % string(baseName, 0, 2)).str();
     createDirs(dir);
 
     if (settings.compressLog) {
 
-        Path logFileName = (format("%1%/%2%.bz2") % dir % baseNameOf(drvPath)).str();
+        Path logFileName = (format("%1%/%2%.bz2") % dir % string(baseName, 2)).str();
         AutoCloseFD fd = open(logFileName.c_str(), O_CREAT | O_WRONLY | O_TRUNC, 0666);
         if (fd == -1) throw SysError(format("creating log file `%1%'") % logFileName);
         closeOnExec(fd);
@@ -2364,7 +2372,7 @@ Path DerivationGoal::openLogFile()
         return logFileName;
 
     } else {
-        Path logFileName = (format("%1%/%2%") % dir % baseNameOf(drvPath)).str();
+        Path logFileName = (format("%1%/%2%") % dir % string(baseName, 2)).str();
         fdLogFile = open(logFileName.c_str(), O_CREAT | O_WRONLY | O_TRUNC, 0666);
         if (fdLogFile == -1) throw SysError(format("creating log file `%1%'") % logFileName);
         closeOnExec(fdLogFile);
@@ -2831,7 +2839,7 @@ void SubstitutionGoal::finished()
         return;
     }
 
-    canonicalisePathMetaData(destPath);
+    canonicalisePathMetaData(destPath, -1);
 
     worker.store.optimisePath(destPath); // FIXME: combine with hashPath()
 
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index a6b1a35e77ef..113a7da15411 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -659,7 +659,10 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
        increase, since we hold locks on everything.  So everything
        that is not reachable from `roots'. */
 
-    if (state.shouldDelete) createDirs(state.trashDir);
+    if (state.shouldDelete) {
+        if (pathExists(state.trashDir)) deleteGarbage(state, state.trashDir);
+        createDirs(state.trashDir);
+    }
 
     /* Now either delete all garbage paths, or just the specified
        paths (for gcDeleteSpecific). */
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index 596d4774ca4d..b5a2a20bee44 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -10,6 +10,14 @@
 namespace nix {
 
 
+/* The default location of the daemon socket, relative to nixStateDir.
+   The socket is in a directory to allow you to control access to the
+   Nix daemon by setting the mode/ownership of the directory
+   appropriately.  (This wouldn't work on the socket itself since it
+   must be deleted and recreated on startup.) */
+#define DEFAULT_SOCKET_PATH "/daemon-socket/socket"
+
+
 Settings settings;
 
 
@@ -58,6 +66,7 @@ void Settings::processEnvironment()
     nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR));
     nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
     nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
+    nixDaemonSocketFile = canonPath(nixStateDir + DEFAULT_SOCKET_PATH);
 
     string subs = getEnv("NIX_SUBSTITUTERS", "default");
     if (subs == "default") {
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index be287698c6c8..f129d9a11edc 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -50,6 +50,9 @@ struct Settings {
     /* The directory where the main programs are stored. */
     Path nixBinDir;
 
+    /* File name of the socket the daemon listens to.  */
+    Path nixDaemonSocketFile;
+
     /* Whether to keep temporary directories of failed builds. */
     bool keepFailed;
 
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 333feb2a5f30..4b8203efe374 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -47,7 +47,11 @@ static void throwSQLiteError(sqlite3 * db, const format & f)
 {
     int err = sqlite3_errcode(db);
     if (err == SQLITE_BUSY) {
-        printMsg(lvlError, "warning: SQLite database is busy");
+        static bool warned = false;
+        if (!warned) {
+            printMsg(lvlError, "warning: SQLite database is busy");
+            warned = true;
+        }
         /* Sleep for a while since retrying the transaction right away
            is likely to fail again. */
 #if HAVE_NANOSLEEP
@@ -461,36 +465,8 @@ void LocalStore::makeStoreWritable()
 const time_t mtimeStore = 1; /* 1 second into the epoch */
 
 
-void canonicalisePathMetaData(const Path & path, bool recurse)
+static void canonicaliseTimestampAndPermissions(const Path & path, const struct stat & st)
 {
-    checkInterrupt();
-
-    struct stat st;
-    if (lstat(path.c_str(), &st))
-        throw SysError(format("getting attributes of path `%1%'") % path);
-
-    /* Really make sure that the path is of a supported type.  This
-       has already been checked in dumpPath(). */
-    assert(S_ISREG(st.st_mode) || S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode));
-
-    /* Change ownership to the current uid.  If it's a symlink, use
-       lchown if available, otherwise don't bother.  Wrong ownership
-       of a symlink doesn't matter, since the owning user can't change
-       the symlink and can't delete it because the directory is not
-       writable.  The only exception is top-level paths in the Nix
-       store (since that directory is group-writable for the Nix build
-       users group); we check for this case below. */
-    if (st.st_uid != geteuid()) {
-#if HAVE_LCHOWN
-        if (lchown(path.c_str(), geteuid(), (gid_t) -1) == -1)
-#else
-        if (!S_ISLNK(st.st_mode) &&
-            chown(path.c_str(), geteuid(), (gid_t) -1) == -1)
-#endif
-            throw SysError(format("changing owner of `%1%' to %2%")
-                % path % geteuid());
-    }
-
     if (!S_ISLNK(st.st_mode)) {
 
         /* Mask out all type related bits. */
@@ -521,18 +497,84 @@ void canonicalisePathMetaData(const Path & path, bool recurse)
 #endif
             throw SysError(format("changing modification time of `%1%'") % path);
     }
+}
+
+
+void canonicaliseTimestampAndPermissions(const Path & path)
+{
+    struct stat st;
+    if (lstat(path.c_str(), &st))
+        throw SysError(format("getting attributes of path `%1%'") % path);
+    canonicaliseTimestampAndPermissions(path, st);
+}
+
+
+typedef std::pair<dev_t, ino_t> Inode;
+typedef set<Inode> InodesSeen;
 
-    if (recurse && S_ISDIR(st.st_mode)) {
+
+static void canonicalisePathMetaData_(const Path & path, uid_t fromUid, InodesSeen & inodesSeen)
+{
+    checkInterrupt();
+
+    struct stat st;
+    if (lstat(path.c_str(), &st))
+        throw SysError(format("getting attributes of path `%1%'") % path);
+
+    /* Really make sure that the path is of a supported type.  This
+       has already been checked in dumpPath(). */
+    assert(S_ISREG(st.st_mode) || S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode));
+
+    /* Fail if the file is not owned by the build user.  This prevents
+       us from messing up the ownership/permissions of files
+       hard-linked into the output (e.g. "ln /etc/shadow $out/foo").
+       However, ignore files that we chown'ed ourselves previously to
+       ensure that we don't fail on hard links within the same build
+       (i.e. "touch $out/foo; ln $out/foo $out/bar"). */
+    if (fromUid != (uid_t) -1 && st.st_uid != fromUid) {
+        assert(!S_ISDIR(st.st_mode));
+        if (inodesSeen.find(Inode(st.st_dev, st.st_ino)) == inodesSeen.end())
+            throw BuildError(format("invalid ownership on file `%1%'") % path);
+        mode_t mode = st.st_mode & ~S_IFMT;
+        assert(S_ISLNK(st.st_mode) || (st.st_uid == geteuid() && (mode == 0444 || mode == 0555) && st.st_mtime == mtimeStore));
+        return;
+    }
+
+    inodesSeen.insert(Inode(st.st_dev, st.st_ino));
+
+    canonicaliseTimestampAndPermissions(path, st);
+
+    /* Change ownership to the current uid.  If it's a symlink, use
+       lchown if available, otherwise don't bother.  Wrong ownership
+       of a symlink doesn't matter, since the owning user can't change
+       the symlink and can't delete it because the directory is not
+       writable.  The only exception is top-level paths in the Nix
+       store (since that directory is group-writable for the Nix build
+       users group); we check for this case below. */
+    if (st.st_uid != geteuid()) {
+#if HAVE_LCHOWN
+        if (lchown(path.c_str(), geteuid(), (gid_t) -1) == -1)
+#else
+        if (!S_ISLNK(st.st_mode) &&
+            chown(path.c_str(), geteuid(), (gid_t) -1) == -1)
+#endif
+            throw SysError(format("changing owner of `%1%' to %2%")
+                % path % geteuid());
+    }
+
+    if (S_ISDIR(st.st_mode)) {
         Strings names = readDirectory(path);
         foreach (Strings::iterator, i, names)
-            canonicalisePathMetaData(path + "/" + *i, true);
+            canonicalisePathMetaData_(path + "/" + *i, fromUid, inodesSeen);
     }
 }
 
 
-void canonicalisePathMetaData(const Path & path)
+void canonicalisePathMetaData(const Path & path, uid_t fromUid)
 {
-    canonicalisePathMetaData(path, true);
+    InodesSeen inodesSeen;
+
+    canonicalisePathMetaData_(path, fromUid, inodesSeen);
 
     /* On platforms that don't have lchown(), the top-level path can't
        be a symlink, since we can't change its ownership. */
@@ -1194,7 +1236,7 @@ Path LocalStore::addToStoreFromDump(const string & dump, const string & name,
             } else
                 writeFile(dstPath, dump);
 
-            canonicalisePathMetaData(dstPath);
+            canonicalisePathMetaData(dstPath, -1);
 
             /* Register the SHA-256 hash of the NAR serialisation of
                the path in the database.  We may just have computed it
@@ -1259,7 +1301,7 @@ Path LocalStore::addTextToStore(const string & name, const string & s,
 
             writeFile(dstPath, s);
 
-            canonicalisePathMetaData(dstPath);
+            canonicalisePathMetaData(dstPath, -1);
 
             HashResult hash = hashPath(htSHA256, dstPath);
 
@@ -1494,7 +1536,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
                 throw SysError(format("cannot move `%1%' to `%2%'")
                     % unpacked % dstPath);
 
-            canonicalisePathMetaData(dstPath);
+            canonicalisePathMetaData(dstPath, -1);
 
             /* !!! if we were clever, we could prevent the hashPath()
                here. */
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 2b0d71380915..14a826b3a58d 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -307,9 +307,9 @@ private:
      without execute permission; setuid bits etc. are cleared)
    - the owner and group are set to the Nix user and group, if we're
      in a setuid Nix installation. */
-void canonicalisePathMetaData(const Path & path);
+void canonicalisePathMetaData(const Path & path, uid_t fromUid);
 
-void canonicalisePathMetaData(const Path & path, bool recurse);
+void canonicaliseTimestampAndPermissions(const Path & path);
 
 MakeError(PathInUse, Error);
 
diff --git a/src/libstore/optimise-store.cc b/src/libstore/optimise-store.cc
index e91c2b1ce52c..d833f3aa05b5 100644
--- a/src/libstore/optimise-store.cc
+++ b/src/libstore/optimise-store.cc
@@ -32,7 +32,7 @@ struct MakeReadOnly
     {
         try {
             /* This will make the path read-only. */
-            if (path != "") canonicalisePathMetaData(path, false);
+            if (path != "") canonicaliseTimestampAndPermissions(path);
         } catch (...) {
             ignoreException();
         }
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 0e62914c022f..2b5a932131c3 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -91,7 +91,7 @@ void RemoteStore::connectToDaemon()
         throw SysError("cannot create Unix domain socket");
     closeOnExec(fdSocket);
 
-    string socketPath = settings.nixStateDir + DEFAULT_SOCKET_PATH;
+    string socketPath = settings.nixDaemonSocketFile;
 
     /* Urgh, sockaddr_un allows path names of only 108 characters.  So
        chdir to the socket directory so that we can pass a relative
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index 46035f4577e3..07f825b9273f 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -53,14 +53,6 @@ typedef enum {
 #define STDERR_ERROR 0x63787470
 
 
-/* The default location of the daemon socket, relative to nixStateDir.
-   The socket is in a directory to allow you to control access to the
-   Nix daemon by setting the mode/ownership of the directory
-   appropriately.  (This wouldn't work on the socket itself since it
-   must be deleted and recreated on startup.) */
-#define DEFAULT_SOCKET_PATH "/daemon-socket/socket"
-
-
 Path readStorePath(Source & from);
 template<class T> T readStorePaths(Source & from);
 
diff --git a/src/nix-daemon/nix-daemon.cc b/src/nix-daemon/nix-daemon.cc
index 35e5c546e97c..9c6766557dde 100644
--- a/src/nix-daemon/nix-daemon.cc
+++ b/src/nix-daemon/nix-daemon.cc
@@ -774,7 +774,7 @@ static void daemonLoop()
         if (fdSocket == -1)
             throw SysError("cannot create Unix domain socket");
 
-        string socketPath = settings.nixStateDir + DEFAULT_SOCKET_PATH;
+        string socketPath = settings.nixDaemonSocketFile;
 
         createDirs(dirOf(socketPath));
 
diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index af4f264a67e6..151ed97e4b8b 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -238,12 +238,6 @@ static void printTree(const Path & path,
     PathSet references;
     store->queryReferences(path, references);
 
-#if 0
-    for (PathSet::iterator i = drv.inputSrcs.begin();
-         i != drv.inputSrcs.end(); ++i)
-        cout << format("%1%%2%\n") % (tailPad + treeConn) % *i;
-#endif
-
     /* Topologically sort under the relation A < B iff A \in
        closure(B).  That is, if derivation A is an (possibly indirect)
        input of B, then A is printed first.  This has the effect of
@@ -251,7 +245,7 @@ static void printTree(const Path & path,
     Paths sorted = topoSortPaths(*store, references);
     reverse(sorted.begin(), sorted.end());
 
-    for (Paths::iterator i = sorted.begin(); i != sorted.end(); ++i) {
+    foreach (Paths::iterator, i, sorted) {
         Paths::iterator j = i; ++j;
         printTree(*i, tailPad + treeConn,
             j == sorted.end() ? tailPad + treeNull : tailPad + treeLine,
@@ -293,7 +287,7 @@ static void opQuery(Strings opFlags, Strings opArgs)
         else if (*i == "--resolve") query = qResolve;
         else if (*i == "--roots") query = qRoots;
         else if (*i == "--use-output" || *i == "-u") useOutput = true;
-        else if (*i == "--force-realise" || *i == "-f") forceRealise = true;
+        else if (*i == "--force-realise" || *i == "--force-realize" || *i == "-f") forceRealise = true;
         else if (*i == "--include-outputs") includeOutputs = true;
         else throw UsageError(format("unknown flag `%1%'") % *i);
 
@@ -460,35 +454,42 @@ static void opReadLog(Strings opFlags, Strings opArgs)
     foreach (Strings::iterator, i, opArgs) {
         Path path = useDeriver(followLinksToStorePath(*i));
 
-        Path logPath = (format("%1%/%2%/%3%") %
-            settings.nixLogDir % drvsLogDir % baseNameOf(path)).str();
-        Path logBz2Path = logPath + ".bz2";
-
-        if (pathExists(logPath)) {
-            /* !!! Make this run in O(1) memory. */
-            string log = readFile(logPath);
-            writeFull(STDOUT_FILENO, (const unsigned char *) log.data(), log.size());
-        }
+        for (int j = 0; j <= 2; j++) {
+            if (j == 2) throw Error(format("build log of derivation `%1%' is not available") % path);
+
+            string baseName = baseNameOf(path);
+            Path logPath =
+                j == 0
+                ? (format("%1%/%2%/%3%/%4%") % settings.nixLogDir % drvsLogDir % string(baseName, 0, 2) % string(baseName, 2)).str()
+                : (format("%1%/%2%/%3%") % settings.nixLogDir % drvsLogDir % baseName).str();
+            Path logBz2Path = logPath + ".bz2";
+
+            if (pathExists(logPath)) {
+                /* !!! Make this run in O(1) memory. */
+                string log = readFile(logPath);
+                writeFull(STDOUT_FILENO, (const unsigned char *) log.data(), log.size());
+                break;
+            }
 
-        else if (pathExists(logBz2Path)) {
-            AutoCloseFD fd = open(logBz2Path.c_str(), O_RDONLY);
-            FILE * f = 0;
-            if (fd == -1 || (f = fdopen(fd.borrow(), "r")) == 0)
-                throw SysError(format("opening file `%1%'") % logBz2Path);
-            int err;
-            BZFILE * bz = BZ2_bzReadOpen(&err, f, 0, 0, 0, 0);
-            if (!bz) throw Error(format("cannot open bzip2 file `%1%'") % logBz2Path);
-            unsigned char buf[128 * 1024];
-            do {
-                int n = BZ2_bzRead(&err, bz, buf, sizeof(buf));
-                if (err != BZ_OK && err != BZ_STREAM_END)
-                    throw Error(format("error reading bzip2 file `%1%'") % logBz2Path);
-                writeFull(STDOUT_FILENO, buf, n);
-            } while (err != BZ_STREAM_END);
-            BZ2_bzReadClose(&err, bz);
+            else if (pathExists(logBz2Path)) {
+                AutoCloseFD fd = open(logBz2Path.c_str(), O_RDONLY);
+                FILE * f = 0;
+                if (fd == -1 || (f = fdopen(fd.borrow(), "r")) == 0)
+                    throw SysError(format("opening file `%1%'") % logBz2Path);
+                int err;
+                BZFILE * bz = BZ2_bzReadOpen(&err, f, 0, 0, 0, 0);
+                if (!bz) throw Error(format("cannot open bzip2 file `%1%'") % logBz2Path);
+                unsigned char buf[128 * 1024];
+                do {
+                    int n = BZ2_bzRead(&err, bz, buf, sizeof(buf));
+                    if (err != BZ_OK && err != BZ_STREAM_END)
+                        throw Error(format("error reading bzip2 file `%1%'") % logBz2Path);
+                    writeFull(STDOUT_FILENO, buf, n);
+                } while (err != BZ_STREAM_END);
+                BZ2_bzReadClose(&err, bz);
+                break;
+            }
         }
-
-        else throw Error(format("build log of derivation `%1%' is not available") % path);
     }
 }
 
@@ -514,7 +515,7 @@ static void registerValidity(bool reregister, bool hashGiven, bool canonicalise)
         if (!store->isValidPath(info.path) || reregister) {
             /* !!! races */
             if (canonicalise)
-                canonicalisePathMetaData(info.path);
+                canonicalisePathMetaData(info.path, -1);
             if (!hashGiven) {
                 HashResult hash = hashPath(htSHA256, info.path);
                 info.hash = hash.first;
@@ -842,7 +843,7 @@ void run(Strings args)
 
         Operation oldOp = op;
 
-        if (arg == "--realise" || arg == "-r")
+        if (arg == "--realise" || arg == "--realize" || arg == "-r")
             op = opRealise;
         else if (arg == "--add" || arg == "-A")
             op = opAdd;
@@ -884,7 +885,7 @@ void run(Strings args)
             op = opVerifyPath;
         else if (arg == "--repair-path")
             op = opRepairPath;
-        else if (arg == "--optimise")
+        else if (arg == "--optimise" || arg == "--optimize")
             op = opOptimise;
         else if (arg == "--query-failed-paths")
             op = opQueryFailedPaths;
diff --git a/substitute.mk b/substitute.mk
index 967ad257b660..940b1206bdd6 100644
--- a/substitute.mk
+++ b/substitute.mk
@@ -37,6 +37,3 @@
 	 -e "s^@testPath\@^$(coreutils):$$(dirname $$(type -p expr))^g" \
 	 < $< > $@ || rm $@
 	if test -x $<; then chmod +x $@; fi
-
-$(CONFIG_HEADER):
-	true
diff --git a/tests/nix-copy-closure.nix b/tests/nix-copy-closure.nix
index db6103b9cbf7..ca09dffac28b 100644
--- a/tests/nix-copy-closure.nix
+++ b/tests/nix-copy-closure.nix
@@ -13,14 +13,14 @@ makeTest ({ pkgs, ... }: let pkgA = pkgs.aterm; pkgB = pkgs.wget; in {
           virtualisation.pathsInNixDB = [ pkgA ];
           environment.nix = nix;
         };
-        
+
       server =
         { config, pkgs, ... }:
         { services.openssh.enable = true;
           virtualisation.writableStore = true;
           virtualisation.pathsInNixDB = [ pkgB ];
           environment.nix = nix;
-        };        
+        };
     };
 
   testScript = { nodes }:
@@ -36,8 +36,8 @@ makeTest ({ pkgs, ... }: let pkgA = pkgs.aterm; pkgB = pkgs.wget; in {
       # Install the SSH key on the server.
       $server->succeed("mkdir -m 700 /root/.ssh");
       $server->copyFileFromHost("key.pub", "/root/.ssh/authorized_keys");
-      $server->waitForJob("sshd");
-      $client->waitForJob("network-interfaces");
+      $server->waitForUnit("sshd");
+      $client->waitForUnit("network.target");
       $client->succeed("ssh -o StrictHostKeyChecking=no " . $server->name() . " 'echo hello world'");
 
       # Copy the closure of package A from the client to the server.
diff --git a/tests/remote-builds.nix b/tests/remote-builds.nix
index b0d2547c66d6..6d38fb568068 100644
--- a/tests/remote-builds.nix
+++ b/tests/remote-builds.nix
@@ -72,11 +72,11 @@ in
       $client->succeed("chmod 600 /root/.ssh/id_dsa");
 
       # Install the SSH key on the slaves.
-      $client->waitForJob("network-interfaces");
+      $client->waitForUnit("network.target");
       foreach my $slave ($slave1, $slave2) {
           $slave->succeed("mkdir -m 700 /root/.ssh");
           $slave->copyFileFromHost("key.pub", "/root/.ssh/authorized_keys");
-          $slave->waitForJob("sshd");
+          $slave->waitForUnit("sshd");
           $client->succeed("ssh -o StrictHostKeyChecking=no " . $slave->name() . " 'echo hello world'");
       }
 
diff --git a/version b/version
index a58941b07a62..8e03717dca27 100644
--- a/version
+++ b/version
@@ -1 +1 @@
-1.3
\ No newline at end of file
+1.5.1
\ No newline at end of file