Method runCommandN

app/shell2/code.cpp:236–308

#define PIPE_READ 0
#define PIPE_WRITE 1
bool FullCommandList::runCommandN(const char *file, ShellState &state,
    ArgumentValueList &args, std::vector<const char *> extraArgv) const {

    int p1[2], p2[2];
    pipe(p1);
    pipe(p2);

    auto pid = fork();
    if(!pid) {
        dup2(p1[PIPE_READ], STDIN_FILENO);
        dup2(p2[PIPE_WRITE], STDOUT_FILENO);
        close(p1[0]); close(p1[1]); close(p2[0]); close(p2[1]);

        unsigned long file0 = (file ? 1 : 0);
        unsigned long extra = extraArgv.size();
        unsigned long count = args.getIndexedCount();
        char **argv = static_cast<char **>(
            malloc((file0 + extra + count + 1) * sizeof(*argv)));
        unsigned long argc = 0;
        if(file0) argv[argc++] = const_cast<char *>(file);
        for(unsigned long i = 0; i < extra; i ++) {
            argv[argc++] = const_cast<char *>(extraArgv[i]);
        }
        for(unsigned long i = 0; i < count; i ++) {
            argv[argc++] = strdup(args.getIndexed(i).getString().c_str());
        }
        argv[argc] = nullptr;
#if 0
        for(unsigned long i = 0; argv[i]; i ++) {
            std::cout << "\"" << argv[i] << "\",";
        }
        std::cout << std::endl;
#endif
        execvp(argv[0], argv);
        std::exit(1);
    }
    else {
        close(p1[PIPE_READ]);
        close(p2[PIPE_WRITE]);
        auto flags = fcntl(p2[PIPE_READ], F_GETFL, 0);
        fcntl(p2[PIPE_READ], F_SETFL, flags | O_NONBLOCK);

        auto in = args.getInStream();
        auto out = args.getOutStream();

        char buffer[BUFSIZ];
        ssize_t n = 0;
        std::string line;
        if(in) while(std::getline(*in, line)) {
            //std::cout << "write [" << line << "]\n";
            line += '\n';
            write(p1[PIPE_WRITE], line.c_str(), line.length());
            if((n = read(p2[PIPE_READ], buffer, sizeof buffer)) > 0) {
                //std::cout << "read [" << buffer << "]\n";
                out->write(buffer, n);
            }
        }
        close(p1[PIPE_WRITE]);