Create a wrapper around stdlib’s rename

Directly takes some c++ strings, and gently throws an exception on error
(rather than having to inline this logic everywhere)

src/libstore/build/derivation-goal.cc

@@ -705,8 +705,7 @@ static void movePath(const Path & src, const Path & dst)
     if (changePerm)
         chmod_(src, st.st_mode | S_IWUSR);
 
-    if (rename(src.c_str(), dst.c_str()))
+    moveFile(src, dst);
-        throw SysError("renaming '%1%' to '%2%'", src, dst);
 
     if (changePerm)
         chmod_(dst, st.st_mode);

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

@@ -223,8 +223,7 @@ static void movePath(const Path & src, const Path & dst)
     if (changePerm)
         chmod_(src, st.st_mode | S_IWUSR);
 
-    if (rename(src.c_str(), dst.c_str()))
+    moveFile(src, dst);
-        throw SysError("renaming '%1%' to '%2%'", src, dst);
 
     if (changePerm)
         chmod_(dst, st.st_mode);
@@ -311,7 +310,7 @@ bool LocalDerivationGoal::cleanupDecideWhetherDiskFull()
             if (buildMode != bmCheck && status.known->isValid()) continue;
             auto p = worker.store.printStorePath(status.known->path);
             if (pathExists(chrootRootDir + p))
-                rename((chrootRootDir + p).c_str(), p.c_str());
+                moveFile((chrootRootDir + p), p);
         }
 
     return diskFull;
@@ -2625,8 +2624,7 @@ DrvOutputs LocalDerivationGoal::registerOutputs()
             Path prev = path + checkSuffix;
             deletePath(prev);
             Path dst = path + checkSuffix;
-            if (rename(path.c_str(), dst.c_str()))
+            moveFile(path, dst);
-                throw SysError("renaming '%s' to '%s'", path, dst);
         }
     }
 

src/libstore/builtins/unpack-channel.cc

@@ -22,8 +22,7 @@ void builtinUnpackChannel(const BasicDerivation & drv)
     auto entries = readDirectory(out);
     if (entries.size() != 1)
         throw Error("channel tarball '%s' contains more than one file", src);
-    if (rename((out + "/" + entries[0].name).c_str(), (out + "/" + channelName).c_str()) == -1)
+    moveFile((out + "/" + entries[0].name), (out + "/" + channelName));
-        throw SysError("renaming channel directory");
 }
 
 }

src/libstore/gc.cc

@@ -39,9 +39,7 @@ static void makeSymlink(const Path & link, const Path & target)
     createSymlink(target, tempLink);
 
     /* Atomically replace the old one. */
-    if (rename(tempLink.c_str(), link.c_str()) == -1)
+    moveFile(tempLink, link);
-        throw SysError("cannot rename '%1%' to '%2%'",
-            tempLink , link);
 }
 
 

src/libstore/local-binary-cache-store.cc

@@ -57,8 +57,7 @@ protected:
         AutoDelete del(tmp, false);
         StreamToSourceAdapter source(istream);
         writeFile(tmp, source);
-        if (rename(tmp.c_str(), path2.c_str()))
+        moveFile(tmp, path2);
-            throw SysError("renaming '%1%' to '%2%'", tmp, path2);
         del.cancel();
     }
 

src/libstore/local-store.cc

@@ -1430,8 +1430,7 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, std::string_view name
                     writeFile(realPath, dumpSource);
             } else {
                 /* Move the temporary path we restored above. */
-                if (rename(tempPath.c_str(), realPath.c_str()))
+                moveFile(tempPath, realPath);
-                    throw Error("renaming '%s' to '%s'", tempPath, realPath);
             }
 
             /* For computing the nar hash. In recursive SHA-256 mode, this
@@ -1942,8 +1941,7 @@ void LocalStore::addBuildLog(const StorePath & drvPath, std::string_view log)
 
     writeFile(tmpFile, compress("bzip2", log));
 
-    if (rename(tmpFile.c_str(), logPath.c_str()) != 0)
+    moveFile(tmpFile, logPath);
-        throw SysError("renaming '%1%' to '%2%'", tmpFile, logPath);
 }
 
 std::optional<std::string> LocalStore::getVersion()

src/libstore/optimise-store.cc

@@ -229,7 +229,9 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
     }
 
     /* Atomically replace the old file with the new hard link. */
-    if (rename(tempLink.c_str(), path.c_str()) == -1) {
+    try {
+        moveFile(tempLink, path);
+    } catch (SysError & e) {
         if (unlink(tempLink.c_str()) == -1)
             printError("unable to unlink '%1%'", tempLink);
         if (errno == EMLINK) {
@@ -240,7 +242,7 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
             debug("'%s' has reached maximum number of links", linkPath);
             return;
         }
-        throw SysError("cannot rename '%1%' to '%2%'", tempLink, path);
+        throw;
     }
 
     stats.filesLinked++;

src/libutil/filesystem.cc

@@ -34,11 +34,16 @@ void replaceSymlink(const Path & target, const Path & link,
             throw;
         }
 
-        if (rename(tmp.c_str(), link.c_str()) != 0)
+        moveFile(tmp, link);
-            throw SysError("renaming '%1%' to '%2%'", tmp, link);
 
         break;
     }
 }
 
+void moveFile(const Path & oldName, const Path & newName)
+{
+    if (::rename(oldName.c_str(), newName.c_str()))
+        throw SysError("renaming '%1%' to '%2%'", oldName, newName);
+}
+
 }

src/libutil/util.hh

@@ -168,6 +168,8 @@ void createSymlink(const Path & target, const Path & link,
 void replaceSymlink(const Path & target, const Path & link,
     std::optional<time_t> mtime = {});
 
+void moveFile(const Path & src, const Path & dst);
+
 
 /* Wrappers arount read()/write() that read/write exactly the
    requested number of bytes. */