Fix some memory leaks

2 files changed, 18 insertions, 6 deletions

diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index 4d6090d66d..7998664ed0 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -893,16 +893,19 @@ pid_t startProcess(std::function<void()> fun,
 }
 
 
+std::vector<const char *> stringsToCharPtrs(const Strings & ss)
+{
+    std::vector<const char *> res;
+    for (auto & s : ss) res.push_back(s.c_str());
+    res.push_back(0);
+    return res;
+}
+
+
 string runProgram(Path program, bool searchPath, const Strings & args)
 {
     checkInterrupt();
 
-    std::vector<const char *> cargs; /* careful with c_str()! */
-    cargs.push_back(program.c_str());
-    for (Strings::const_iterator i = args.begin(); i != args.end(); ++i)
-        cargs.push_back(i->c_str());
-    cargs.push_back(0);
-
     /* Create a pipe. */
     Pipe pipe;
     pipe.create();
@@ -912,6 +915,10 @@ string runProgram(Path program, bool searchPath, const Strings & args)
         if (dup2(pipe.writeSide, STDOUT_FILENO) == -1)
             throw SysError("dupping stdout");
 
+        Strings args_(args);
+        args_.push_front(program);
+        auto cargs = stringsToCharPtrs(args_);
+
         if (searchPath)
             execvp(program.c_str(), (char * *) &cargs[0]);
         else
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
index 8a48a2b7f2..6a84ed8851 100644
--- a/nix/libutil/util.hh
+++ b/nix/libutil/util.hh
@@ -281,6 +281,11 @@ string runProgram(Path program, bool searchPath = false,
 
 MakeError(ExecError, Error)
 
+/* Convert a list of strings to a null-terminated vector of char
+   *'s. The result must not be accessed beyond the lifetime of the
+   list of strings. */
+std::vector<const char *> stringsToCharPtrs(const Strings & ss);
+
 /* Close all file descriptors except stdin, stdout, stderr, and those
    listed in the given set.  Good practice in child processes. */
 void closeMostFDs(const set<int> & exceptions);