Revert "libutil: use makeTempPath in createTempSubdir"

Revert submission 3850

Reason for revert: caused multiple regressions noticed in https://git.lix.systems/lix-project/lix/issues/975 and https://git.lix.systems/lix-project/lix/issues/966 (suspected).

Root cause analysis has not been done yet and this breaks Lix on Darwin on HEAD.

Reverted changes: /q/submissionid:3850

Change-Id: I22d2c315bd8b1eed536c08f2d5b368331907f994

lix/libstore/build/local-derivation-goal.cc

@@ -447,7 +447,7 @@ try {
         /* Create a temporary directory where the build will take
            place. */
         tmpDirRoot =
-            createTempDir(buildDir, "nix-build-" + std::string(drvPath.name()), 0700);
+            createTempDir(buildDir, "nix-build-" + std::string(drvPath.name()), false, false, 0700);
     } catch (SysError & e) {
         /*
          * Fallback to the global tmpdir and create a safe space there
@@ -466,7 +466,7 @@ try {
         constexpr int toplevelDirMode = 0700;
 #endif
         auto nixBuildsTmp = createTempDir(
-            "", fmt("nix-builds-%s", geteuid()), toplevelDirMode
+            "", fmt("nix-builds-%s", geteuid()), false, false, toplevelDirMode
         );
         warn(
             "Failed to use the system-wide build directory '%s', falling back to a temporary "
@@ -475,7 +475,7 @@ try {
             nixBuildsTmp
         );
         tmpDirRoot = createTempDir(
-            nixBuildsTmp, "nix-build-" + std::string(drvPath.name()), 0700
+            nixBuildsTmp, "nix-build-" + std::string(drvPath.name()), false, false, 0700
         );
         worker.buildDirOverride = nixBuildsTmp;
     }

lix/libstore/ssh.cc

@@ -25,7 +25,7 @@ SSH::SSH(const std::string & host, const std::optional<uint16_t> port, const std
         throw Error("invalid SSH host name '%s'", host);
 
     auto state(state_.lock());
-    state->tmpDir = std::make_unique<AutoDelete>(createTempDir("", "nix", 0700));
+    state->tmpDir = std::make_unique<AutoDelete>(createTempDir("", "nix", true, true, 0700));
 }
 
 void SSH::addCommonSSHOpts(Strings & args)

lix/libstore/temporary-dir.cc

@@ -5,9 +5,10 @@
 
 namespace nix {
 
-Path createTempDir(const Path & tmpRoot, const Path & prefix, mode_t mode)
+Path createTempDir(const Path & tmpRoot, const Path & prefix,
+    bool includePid, bool useGlobalCounter, mode_t mode)
 {
-    return createTempSubdir(tmpRoot.empty() ? defaultTempDir() : tmpRoot, prefix, mode);
+    return createTempSubdir(tmpRoot.empty() ? defaultTempDir() : tmpRoot, prefix, includePid, useGlobalCounter, mode);
 }
 
 std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)

lix/libstore/temporary-dir.hh

@@ -8,7 +8,8 @@ namespace nix {
 /**
  * Create a temporary directory.
  */
-Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix", mode_t mode = 0755);
+Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
+    bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
 
 /**
  * Create a temporary file, returning a file handle and its path.

lix/libutil/file-system.cc

@@ -646,28 +646,44 @@ void AutoDelete::reset(const Path & p, bool recursive) {
 
 //////////////////////////////////////////////////////////////////////
 
-Path createTempSubdir(const Path & parent, const Path & prefix,
-    mode_t mode)
+static Path tempName(PathView parent, const Path & prefix, bool includePid,
+    std::atomic<unsigned int> & counter)
 {
-    checkInterrupt();
-    Path tmpDir = makeTempPath(parent + "/", prefix);
-    if (mkdir(tmpDir.c_str(), mode) == 0) {
+    auto tmpRoot = canonPath(parent, true);
+    if (includePid)
+        return fmt("%1%/%2%-%3%-%4%", tmpRoot, prefix, getpid(), counter++);
+    else
+        return fmt("%1%/%2%-%3%", tmpRoot, prefix, counter++);
+}
+
+Path createTempSubdir(const Path & parent, const Path & prefix,
+    bool includePid, bool useGlobalCounter, mode_t mode)
+{
+    static std::atomic<unsigned int> globalCounter = 0;
+    std::atomic<unsigned int> localCounter = 0;
+    auto & counter(useGlobalCounter ? globalCounter : localCounter);
+
+    while (1) {
+        checkInterrupt();
+        Path tmpDir = tempName(parent, prefix, includePid, counter);
+        if (mkdir(tmpDir.c_str(), mode) == 0) {
 #if __FreeBSD__
-        /* Explicitly set the group of the directory.  This is to
-           work around around problems caused by BSD's group
-           ownership semantics (directories inherit the group of
-           the parent).  For instance, the group of /tmp on
-           FreeBSD is "wheel", so all directories created in /tmp
-           will be owned by "wheel"; but if the user is not in
-           "wheel", then "tar" will fail to unpack archives that
-           have the setgid bit set on directories. */
-        if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0) {
-            throw SysError("setting group of directory '%1%'", tmpDir);
-        }
+            /* Explicitly set the group of the directory.  This is to
+               work around around problems caused by BSD's group
+               ownership semantics (directories inherit the group of
+               the parent).  For instance, the group of /tmp on
+               FreeBSD is "wheel", so all directories created in /tmp
+               will be owned by "wheel"; but if the user is not in
+               "wheel", then "tar" will fail to unpack archives that
+               have the setgid bit set on directories. */
+            if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
+                throw SysError("setting group of directory '%1%'", tmpDir);
 #endif
-        return tmpDir;
+            return tmpDir;
+        }
+        if (errno != EEXIST)
+            throw SysError("creating directory '%1%'", tmpDir);
     }
-    throw SysError("creating directory '%1%'", tmpDir);
 }
 
 Path makeTempPath(const Path & root, const Path & prefix)

lix/libutil/file-system.hh

@@ -308,7 +308,7 @@ typedef std::unique_ptr<DIR, DIRDeleter> AutoCloseDir;
  * Create a temporary directory in a given parent directory.
  */
 Path createTempSubdir(const Path & parent, const Path & prefix = "nix",
-    mode_t mode = 0755);
+    bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
 
 /**
  * Return temporary path constructed by appending to a root path.