Don't use std::cerr in a few places

Slightly scared of using std::cerr in a vforked process...

src/libstore/build.cc

@@ -10,7 +10,6 @@
 #include "immutable.hh"
 
 #include <map>
-#include <iostream>
 #include <sstream>
 #include <algorithm>
 #include <boost/shared_ptr.hpp>
@@ -565,7 +564,7 @@ static void runSetuidHelper(const string & command,
             throw SysError(format("executing `%1%'") % program);
         }
         catch (std::exception & e) {
-            std::cerr << "error: " << e.what() << std::endl;
+            writeToStderr("error: " + string(e.what()) + "\n");
         }
         _exit(1);
     }
@@ -695,7 +694,7 @@ HookInstance::HookInstance()
             throw SysError(format("executing `%1%'") % buildHook);
 
         } catch (std::exception & e) {
-            std::cerr << format("build hook error: %1%") % e.what() << std::endl;
+            writeToStderr("build hook error: " + string(e.what()) + "\n");
         }
         _exit(1);
     }
@@ -1547,7 +1546,7 @@ HookReply DerivationGoal::tryBuildHook()
             break;
         }
         s += "\n";
-        writeToStderr((unsigned char *) s.data(), s.size());
+        writeToStderr(s);
     }
 
     debug(format("hook reply is `%1%'") % reply);
@@ -2141,7 +2140,7 @@ void DerivationGoal::initChild()
         throw SysError(format("executing `%1%'") % drv.builder);
 
     } catch (std::exception & e) {
-        std::cerr << format("build error: %1%") % e.what() << std::endl;
+        writeToStderr("build error: " + string(e.what()) + "\n");
         _exit(inSetup ? childSetupFailed : 1);
     }
 
@@ -2362,7 +2361,7 @@ void DerivationGoal::handleChildOutput(int fd, const string & data)
         (!hook && fd == builderOut.readSide))
     {
         if (verbosity >= settings.buildVerbosity)
-            writeToStderr((unsigned char *) data.data(), data.size());
+            writeToStderr(data);
         if (bzLogFile) {
             int err;
             BZ2_bzWrite(&err, bzLogFile, (unsigned char *) data.data(), data.size());
@@ -2372,7 +2371,7 @@ void DerivationGoal::handleChildOutput(int fd, const string & data)
     }
 
     if (hook && fd == hook->fromHook.readSide)
-        writeToStderr((unsigned char *) data.data(), data.size());
+        writeToStderr(data);
 }
 
 
@@ -2693,7 +2692,7 @@ void SubstitutionGoal::tryToRun()
             throw SysError(format("executing `%1%'") % sub);
 
         } catch (std::exception & e) {
-            std::cerr << format("substitute error: %1%") % e.what() << std::endl;
+            writeToStderr("substitute error: " + string(e.what()) + "\n");
         }
         _exit(1);
     }
@@ -2809,8 +2808,7 @@ void SubstitutionGoal::finished()
 void SubstitutionGoal::handleChildOutput(int fd, const string & data)
 {
     assert(fd == logPipe.readSide);
-    if (verbosity >= settings.buildVerbosity)
+    if (verbosity >= settings.buildVerbosity) writeToStderr(data);
-        writeToStderr((unsigned char *) data.data(), data.size());
     /* Don't write substitution output to a log file for now.  We
        probably should, though. */
 }

src/libstore/remote-store.cc

@@ -556,7 +556,7 @@ void RemoteStore::processStderr(Sink * sink, Source * source)
         }
         else {
             string s = readString(from);
-            writeToStderr((const unsigned char *) s.data(), s.size());
+            writeToStderr(s);
         }
     }
     if (msg == STDERR_ERROR) {

src/libutil/util.cc

@@ -483,16 +483,7 @@ void printMsg_(Verbosity level, const format & f)
     else if (logType == ltEscapes && level != lvlInfo)
         prefix = "\033[" + escVerbosity(level) + "s";
     string s = (format("%1%%2%\n") % prefix % f.str()).str();
-    try {
+    writeToStderr(s);
-        writeToStderr((const unsigned char *) s.data(), s.size());
-    } catch (SysError & e) {
-        /* Ignore failing writes to stderr if we're in an exception
-           handler, otherwise throw an exception.  We need to ignore
-           write errors in exception handlers to ensure that cleanup
-           code runs to completion if the other side of stderr has
-           been closed unexpectedly. */
-        if (!std::uncaught_exception()) throw;
-    }
 }
 
 
@@ -505,13 +496,28 @@ void warnOnce(bool & haveWarned, const format & f)
 }
 
 
+void writeToStderr(const string & s)
+{
+    try {
+        _writeToStderr((const unsigned char *) s.data(), s.size());
+    } catch (SysError & e) {
+        /* Ignore failing writes to stderr if we're in an exception
+           handler, otherwise throw an exception.  We need to ignore
+           write errors in exception handlers to ensure that cleanup
+           code runs to completion if the other side of stderr has
+           been closed unexpectedly. */
+        if (!std::uncaught_exception()) throw;
+    }
+}
+
+
 static void defaultWriteToStderr(const unsigned char * buf, size_t count)
 {
     writeFull(STDERR_FILENO, buf, count);
 }
 
 
-void (*writeToStderr) (const unsigned char * buf, size_t count) = defaultWriteToStderr;
+void (*_writeToStderr) (const unsigned char * buf, size_t count) = defaultWriteToStderr;
 
 
 void readFull(int fd, unsigned char * buf, size_t count)
@@ -845,8 +851,7 @@ void killUser(uid_t uid)
 	    }
 
         } catch (std::exception & e) {
-            std::cerr << format("killing processes belonging to uid `%1%': %2%")
+            writeToStderr((format("killing processes belonging to uid `%1%': %2%\n") % uid % e.what()).str());
-                % uid % e.what() << std::endl;
             _exit(1);
         }
         _exit(0);
@@ -902,7 +907,7 @@ string runProgram(Path program, bool searchPath, const Strings & args)
             throw SysError(format("executing `%1%'") % program);
 
         } catch (std::exception & e) {
-            std::cerr << "error: " << e.what() << std::endl;
+            writeToStderr("error: " + string(e.what()) + "\n");
         }
         _exit(1);
     }

src/libutil/util.hh

@@ -148,7 +148,9 @@ void printMsg_(Verbosity level, const format & f);
 
 void warnOnce(bool & haveWarned, const format & f);
 
-extern void (*writeToStderr) (const unsigned char * buf, size_t count);
+void writeToStderr(const string & s);
+
+extern void (*_writeToStderr) (const unsigned char * buf, size_t count);
 
 
 /* Wrappers arount read()/write() that read/write exactly the

src/nix-daemon/nix-daemon.cc

@@ -6,7 +6,6 @@
 #include "archive.hh"
 #include "globals.hh"
 
-#include <iostream>
 #include <cstring>
 #include <unistd.h>
 #include <signal.h>
@@ -642,7 +641,7 @@ static void processConnection()
 {
     canSendStderr = false;
     myPid = getpid();
-    writeToStderr = tunnelStderr;
+    _writeToStderr = tunnelStderr;
 
 #ifdef HAVE_HUP_NOTIFICATION
     /* Allow us to receive SIGPOLL for events on the client socket. */
@@ -877,7 +876,7 @@ static void daemonLoop()
                     processConnection();
 
                 } catch (std::exception & e) {
-                    std::cerr << format("child error: %1%\n") % e.what();
+                    writeToStderr("child error: " + string(e.what()) + "\n");
                 }
                 exit(0);
             }