Initial commit

2 files changed, 43 insertions, 0 deletions

diff --git a/src/withExtendedPath/TARGETS b/src/withExtendedPath/TARGETS
new file mode 100644
index 0000000..e226541
--- /dev/null
+++ b/src/withExtendedPath/TARGETS
@@ -0,0 +1,6 @@
+{ "":
+  { "type": ["@", "rules", "CC", "binary"]
+  , "name": ["withExtendedPath"]
+  , "srcs": ["extend-path.cc"]
+  }
+}
diff --git a/src/withExtendedPath/extend-path.cc b/src/withExtendedPath/extend-path.cc
new file mode 100644
index 0000000..a466728
--- /dev/null
+++ b/src/withExtendedPath/extend-path.cc
@@ -0,0 +1,37 @@
+#include <algorithm>
+#include <cstdlib>
+#include <string>
+#include <unistd.h>
+#include <vector>
+
+int main(int argc, char* argv[]) {
+  constexpr int kForkFailed = 65;
+  constexpr int kPrerequisiteError = 97;
+  auto kEnv = std::string{"/usr/bin/env"};
+
+  if (argc < 3) {
+    return kPrerequisiteError;
+  }
+
+  // compute PATH
+  auto path = std::string{argv[1]};
+  auto const* env_path = std::getenv("PATH");
+  if (env_path && (*env_path != '\0')) {
+    path = std::string{env_path} + std::string{":"} + path;
+  }
+  auto path_arg = std::string{"PATH="} + path;
+
+  // create new argument vector
+  std::vector<char*> nargv{};
+  nargv.reserve(argc+3);
+  nargv.push_back(kEnv.data());
+  nargv.push_back(path_arg.data());
+  for (int i=2; i < argc; i++) {
+    nargv.push_back(argv[i]);
+  }
+  nargv.push_back(nullptr);
+
+  // exec
+  (void) execvp(nargv[0], static_cast<char* const*>(nargv.data()));
+  return kForkFailed;
+}