Migrate exec function to C++ arrays

native/jni/utils/misc.cpp

@@ -193,3 +193,78 @@ ssize_t __getline(char **lineptr, size_t *n, FILE *stream) {
 int __fsetxattr(int fd, const char *name, const void *value, size_t size, int flags) {
 	return (int) syscall(__NR_fsetxattr, fd, name, value, size, flags);
 }
+
+/*
+   fd == NULL -> Ignore output
+  *fd < 0     -> Open pipe and set *fd to the read end
+  *fd >= 0    -> STDOUT (or STDERR) will be redirected to *fd
+  *cb         -> A callback function which calls after forking
+*/
+int exec_array(int err, int *fd, void (*cb)(void), const char *argv[]) {
+	int pipefd[2], write_end = -1;
+
+	if (fd) {
+		if (*fd < 0) {
+			if (xpipe2(pipefd, O_CLOEXEC) == -1)
+				return -1;
+			write_end = pipefd[1];
+		} else {
+			write_end = *fd;
+		}
+	}
+
+	int pid = xfork();
+	if (pid != 0) {
+		if (fd && *fd < 0) {
+			// Give the read end and close write end
+			*fd = pipefd[0];
+			close(pipefd[1]);
+		}
+		return pid;
+	}
+
+	if (fd) {
+		xdup2(write_end, STDOUT_FILENO);
+		if (err)
+			xdup2(write_end, STDERR_FILENO);
+	}
+
+	// Setup environment
+	if (cb)
+		cb();
+
+	execvp(argv[0], (char **) argv);
+	PLOGE("execvp %s", argv[0]);
+	return -1;
+}
+
+static int v_exec_command(int err, int *fd, void (*cb)(void), const char *argv0, va_list argv) {
+	// Collect va_list into vector
+	Array<const char *> args;
+	args.push_back(argv0);
+	for (const char *arg = va_arg(argv, char*); arg; arg = va_arg(argv, char*))
+		args.push_back(arg);
+	args.push_back(nullptr);
+	int pid = exec_array(err, fd, cb, args.data());
+	return pid;
+}
+
+int exec_command_sync(const char *argv0, ...) {
+	va_list argv;
+	va_start(argv, argv0);
+	int pid, status;
+	pid = v_exec_command(0, NULL, NULL, argv0, argv);
+	va_end(argv);
+	if (pid < 0)
+		return pid;
+	waitpid(pid, &status, 0);
+	return WEXITSTATUS(status);
+}
+
+int exec_command(int err, int *fd, void (*cb)(void), const char *argv0, ...) {
+	va_list argv;
+	va_start(argv, argv0);
+	int pid = v_exec_command(err, fd, cb, argv0, argv);
+	va_end(argv);
+	return pid;
+}