Move sources to ... well, src ;)

1 files changed, 87 insertions, 0 deletions

diff --git a/src/execute.cc b/src/execute.cc
new file mode 100644
index 0000000..bc4cd5f
--- /dev/null
+++ b/src/execute.cc
@@ -0,0 +1,87 @@
+#include "execute.h"
+
+#include <unistd.h>
+#include <cstring>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <spawn.h>
+#include <iostream>
+
+/*
+https://blog.famzah.net/2009/11/20/a-much-faster-popen-and-system-implementation-for-linux/
+https://github.com/famzah/popen-noshell/commit/1f9eaf4eeef348d1efe0f3c7fe8ab670653cfbb1
+https://blog.famzah.net/2018/12/19/posix_spawn-performance-benchmarks-and-usage-examples/
+https://stackoverflow.com/questions/4259629/what-is-the-difference-between-fork-and-vfork/5207945#5207945
+ */
+
+
+namespace
+{
+int parent_waitpid(pid_t pid)
+{
+	int status;
+
+	if(waitpid(pid, &status, 0) != pid)
+	{
+		return 1;
+	}
+
+	return status;
+}
+} // namespace ::
+
+int execute(const std::string& command,
+            const std::vector<std::string>& args,
+            bool verbose)
+{
+	std::vector<const char*> argv;
+	argv.push_back(command.data());
+	for(const auto& arg : args)
+	{
+		argv.push_back(arg.data());
+	}
+	argv.push_back(nullptr);
+
+	if(verbose)
+	{
+		std::string cmd;
+		for(const auto& arg : argv)
+		{
+			if(arg == nullptr)
+			{
+				break;
+			}
+			if(!cmd.empty())
+			{
+				cmd += " ";
+			}
+			cmd += arg;
+		}
+
+		std::cout << cmd << "\n";
+	}
+
+#if 1
+	auto pid = vfork();
+	if(pid == 0)
+	{
+		execv(command.data(), (char**)argv.data());
+		std::cout << "Could not execute " << command << ": " <<
+			strerror(errno) << "\n";
+		_exit(1); // execv only returns if an error occurred
+	}
+	auto ret = parent_waitpid(pid);
+#elif 0
+	pid_t pid;
+	if(posix_spawn(&pid, command.data(), nullptr, nullptr,
+	               (char**)argv.data(), nullptr))
+	{
+		return 1;
+	}
+	auto ret = parent_waitpid(pid);
+#else
+	auto ret = system(cmd.data());
+#endif
+
+	return ret;
+}