popen: allow passing of new env variables, working directory and non-shell execution

common/include/villas/popen.hpp

@@ -27,6 +27,7 @@
 
 #include <ext/stdio_filebuf.h>
 
+#include <map>
 #include <string>
 #include <istream>
 #include <ostream>
@@ -38,10 +39,17 @@ namespace utils {
 class Popen {
 
 public:
+	using arg_list = std::vector<std::string>;
+	using env_map = std::map<std::string, std::string>;
+
 	using char_type = char;
 	using stdio_buf = __gnu_cxx::stdio_filebuf<char_type>;
 
-	Popen(const std::string &command);
+	Popen(const std::string &cmd,
+	      const arg_list &args = arg_list(),
+	      const env_map &env = env_map(),
+	      const std::string &wd = std::string(),
+	      bool shell = false);
 	~Popen();
 
 	void open();
@@ -70,6 +78,10 @@ public:
 
 protected:
 	std::string command;
+	std::string working_dir;
+	arg_list arguments;
+	env_map environment;
+	bool shell;
 	pid_t pid;
 
 	struct {
@@ -81,7 +93,6 @@ protected:
 		std::unique_ptr<std::ostream> stream;
 		std::unique_ptr<stdio_buf> buffer;
 	} output;
-
 };
 
 } /* namespace utils */

common/lib/popen.cpp

@@ -20,26 +20,40 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *********************************************************************************/
 
-#include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <signal.h>
 #include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <unistd.h>
 #include <paths.h>
 #include <dirent.h>
 
+#include <cstring>
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+
+#include <iostream>
+
+#include <fmt/core.h>
+#include <villas/utils.hpp>
 #include <villas/exceptions.hpp>
 #include <villas/popen.hpp>
 
 namespace villas {
 namespace utils {
 
-Popen::Popen(const std::string &cmd) :
-	command(cmd)
+Popen::Popen(const std::string &cmd,
+             const arg_list &args,
+             const env_map &env,
+             const std::string &wd,
+             bool sh) :
+	command(cmd),
+	working_dir(wd),
+	arguments(args),
+	environment(env),
+	shell(sh)
 {
 	open();
 }
@@ -56,13 +70,14 @@ void Popen::kill(int signal)
 
 void Popen::open()
 {
+	std::vector<char *> argv, envp;
+
 	const int READ = 0;
 	const int WRITE = 1;
 
 	int ret;
 	int inpipe[2];
 	int outpipe[2];
-	char *argv[4];
 
 	ret = pipe(inpipe);
 	if (ret)
@@ -83,6 +98,35 @@ void Popen::open()
 		goto clean_outpipe_out;
 
 	if (pid == 0) {
+		/* Prepare arguments */
+		if (shell) {
+			argv.push_back((char *) "sh");
+			argv.push_back((char *) "-c");
+			argv.push_back((char *) command.c_str());
+		}
+		else {
+			for (auto arg: arguments) {
+				auto s = strdup(arg.c_str());
+
+				argv.push_back(s);
+			}
+		}
+
+		/* Prepare environment */
+		for (char **p = environ; *p; p++)
+			envp.push_back(*p);
+
+		for (auto env: environment) {
+			auto e = fmt::format("{}={}", env.first, env.second);
+			auto s = strdup(e.c_str());
+
+			envp.push_back(s);
+		}
+
+		argv.push_back(nullptr);
+		envp.push_back(nullptr);
+
+		/* Redirect IO */
 		::close(outpipe[READ]);
 		::close(inpipe[WRITE]);
 
@@ -96,12 +140,11 @@ void Popen::open()
 			::close(outpipe[WRITE]);
 		}
 
-		argv[0] = (char *) "sh";
-		argv[1] = (char *) "-c";
-		argv[2] = (char *) command.c_str();
-		argv[3] = nullptr;
+		/* Change working directory */
+		if (!working_dir.empty())
+			chdir(working_dir.c_str());
 
-		execv(_PATH_BSHELL, (char * const *) argv);
+		execvpe(shell ? _PATH_BSHELL : command.c_str(), (char * const *) argv.data(), (char * const *) envp.data());
 		exit(127);
 	}
 

common/tests/unit/popen.cpp

@@ -29,9 +29,9 @@ using namespace villas::utils;
 
 TestSuite(popen, .description = "Bi-directional popen");
 
-Test(popen, cat)
+Test(popen, no_shell)
 {
-	Popen proc("cat");
+	Popen proc("/usr/bin/tee", {"tee", "test"});
 
 	proc.cout() << "Hello World" << std::endl;
 	proc.cout().flush();
@@ -40,9 +40,54 @@ Test(popen, cat)
 
 	proc.cin() >> str >> str2;
 
+	std::cout << str << str2 << std::endl;
+
+	cr_assert_eq(str, "Hello");
+	cr_assert_eq(str2, "World");
+
+	proc.kill();
+	proc.close();
+}
+
+Test(popen, shell)
+{
+	Popen proc("echo \"Hello World\"", {}, {}, std::string(), true);
+
+	std::string str, str2;
+
+	proc.cin() >> str >> str2;
+
 	cr_assert_eq(str, "Hello");
 	cr_assert_eq(str2, "World");
 
 	proc.kill();
 	proc.close();
 }
+
+Test(popen, wd)
+{
+	Popen proc("/usr/bin/pwd", {"pwd"}, {}, "/usr/lib");
+
+	std::string wd;
+
+	proc.cin() >> wd;
+
+	cr_assert_eq(wd, "/usr/lib");
+
+	proc.kill();
+	proc.close();
+}
+
+Test(popen, env)
+{
+	Popen proc("echo $MYVAR", {}, {{"MYVAR", "TESTVAL"}}, std::string(), true);
+
+	std::string var;
+
+	proc.cin() >> var;
+
+	cr_assert_eq(var, "TESTVAL");
+
+	proc.kill();
+	proc.close();
+}