\u672c\u7bc7\u53c2\u8003\u4e66\u76ee\u300aLinux\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u7f16\u7a0b\u300b，\u8fd9\u662f\u6211\u7b2c\u4e09\u6b21\u5b9e\u73b0\u7f51\u7edc\u804a\u5929\u5ba4，\u8fd9\u4e00\u6b21\u662f\u5728\u5185\u5b58\u7684\u65b9\u9762\u8fdb\u884c\u4e86\u6781\u5927\u7684\u6539\u8fdb，\u5e76\u4e14\u672c\u7bc7\u6587\u7ae0\u4e3b\u8981\u4f7f\u7528c++11\u6765\u5b9e\u73b0\u7684，\u5c06\u4e66\u672c\u91cc\u9762\u7684c\u8bed\u8a00\u91cd\u5199\u4e86\u4e00\u904d\u3002<\/p>\n
\u4ee3\u7801\u5df2\u7ecf\u4e0a\u4f20\u5230\u4e86github\u4e0a\u9762，fengyue05\/Linux-: \u672c\u4ed3\u5e93\u91cc\u9762\u4f1a\u6709\u5173\u4e8e\u300aLinux\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u7f16\u7a0b\u300b\u7684\u4e00\u4e9b\u4e3b\u8981\u4ee3\u7801\u5b9e\u73b0<\/p>\n
\u5728\u5f00\u59cb\u771f\u6b63\u4ee3\u7801\u7684\u5b9e\u73b0\u524d\u9762，\u6211\u4eec\u9700\u8981\u51c6\u5907\u4e00\u4e9b\u53d8\u91cf，\u9996\u5148\u662f\u7f13\u5b58\u7684\u5927\u5c0f，\u7528\u6237\u7684\u9650\u5236，\u4e8b\u4ef6\u7684\u9650\u5236，\u8fdb\u7a0b\u6570\u91cf\u7684\u9650\u5236\u3002\u6211\u4eec\u8fd9\u91cc\u4e3b\u8981\u662f\u901a\u8fc7\u4e3b\u8fdb\u7a0b\u6765\u63a5\u53d7\u8fde\u63a5，\u5e7f\u64ad\u6d88\u606f，\u5176\u5b9e\u76f8\u5f53\u4e8e\u6211\u4eec\u7684\u670d\u52a1\u5668\u7aef，\u800c\u4e3b\u8fdb\u7a0b\u521b\u5efa\u51fa\u6765\u7684\u5b50\u8fdb\u7a0b\u4f5c\u7528\u662f\u548c\u5ba2\u6237\u7aef\u8fde\u63a5\u3002\u6240\u4ee5\u6211\u4eec\u5ba2\u6237\u7aef\u7684\u6570\u636e\u7ed3\u6784\u4f53\u91cc\u9762\u5305\u542b\u4e86\u5176\u5730\u5740，\u5bf9\u5e94\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26，\u5bf9\u5e94\u7684\u8fdb\u7a0b，\u8fd8\u6709\u6700\u91cd\u8981\u7684\u5c31\u662f\u4e00\u4e2a\u7ba1\u9053，\u6211\u4eec\u7684\u5b50\u8fdb\u7a0b\u53ea\u80fd\u548c\u7236\u8fdb\u7a0b\u901a\u4fe1，\u6240\u4ee5\u6211\u4eec\u901a\u8fc7\u7ba1\u9053\u6765\u901a\u4fe1，\u6211\u4eec\u901a\u8fc7socketpair\u628a\u7ba1\u9053\u4e24\u8fb9\u5c01\u88c5socket，\u7136\u540e\u7236\u8fdb\u7a0b\u4f7f\u7528pipefd[0]，\u5b50\u8fdb\u7a0b\u4f7f\u7528pipefd[1]<\/p>\n
\u7136\u540e\u7236\u8fdb\u7a0b\u4f5c\u4e3a\u670d\u52a1\u5668\u8fd8\u9700\u8981\u5904\u7406\u4fe1\u53f7\u7684\u5230\u6765，\u8fd9\u91cc\u6211\u4eec\u4e5f\u4f7f\u7528\u7ba1\u9053\u6765\u901a\u4fe1\u5904\u7406\u3002\u6700\u540e\u6211\u4eec\u662f\u901a\u8fc7\u5171\u4eab\u5185\u5b58\u7684\u65b9\u5f0f\u8fdb\u884c\u4fe1\u606f\u7684\u4ea4\u6d41，\u9700\u8981\u4e00\u4e2a\u6307\u9488\u3002<\/p>\n
\u4e3a\u4e86\u65b9\u4fbf\u6211\u4eec\u7684\u4ee3\u7801，\u6211\u4eec\u7279\u610f\u5f00\u8f9f\u4e86\u4e24\u4e2a\u6570\u7ec4，\u4e00\u4e2a\u6570\u7ec4\u662f\u5b58\u7528\u6237\u7684\u6570\u636e，\u4e00\u4e2a\u6570\u7ec4\u662f\u5b58\u8fdb\u7a0b，\u65b9\u4fbf\u540e\u9762\u4f7f\u7528\u3002<\/p>\n
\u6700\u540e\u6211\u4eec\u9700\u8981\u5f3a\u8c03\u4e00\u4e2avolatile，\u8fd9\u4e2a\u53d8\u91cf\u7684\u503c\u53ef\u80fd\u5728\u7a0b\u5e8f\u201c\u770b\u4e0d\u5230\u7684\u5730\u65b9\u201d\u88ab\u6539\u53d8，\u6240\u4ee5\u6bcf\u6b21\u4f7f\u7528\u5b83\u65f6，\u90fd\u5e94\u8be5\u91cd\u65b0\u4ece\u5185\u5b58\u8bfb\u53d6，\u4e0d\u8981\u8fc7\u5ea6\u4f18\u5316\u3002<\/p>\n
sig_atomic_t \u5f3a\u8c03\u7684\u662f\u539f\u5b50\u6027，\u7279\u522b\u662f\u4e0d\u4f1a\u88ab\u4fe1\u53f7\u6253\u65ad\u3002<\/p>\n
constexpr int USER_LIMIT = 5;
\nconstexpr int BUFFER_SIZE = 1024;
\nconstexpr int FD_LIMIT = 65535;
\nconstexpr int MAX_EVENT_NUMBER = 1024;
\nconstexpr int PROCESS_LIMIT = 65535;
\nconstexpr const char* SHM_NAME = "\/my_shm";<\/p>\n
struct ClientData {
\n sockaddr_in address;
\n int connfd;
\n pid_t pid; \/\/ \u5904\u7406\u8fd9\u4e2a\u8fde\u63a5\u7684\u5b50\u8fdb\u7a0b\u7684PID
\n std::array<int, 2> pipefd; \/\/ \u548c\u7236\u8fdb\u7a0b\u901a\u4fe1\u7684\u7ba1\u9053
\n};<\/p>\n
std::array<int, 2> m_signalPipe{{-1, -1}};
\nint m_epollfd = -1;
\nint m_listened = -1;
\nchar* m_sharedMemory = nullptr;<\/p>\n
\/\/ \u5ba2\u6237\u8fde\u63a5\u6570\u7ec4\u3002\u8fdb\u7a0b\u7528\u5ba2\u6237\u8fde\u63a5\u7684\u7f16\u53f7\u6765\u7d22\u5f15\u8fd9\u4e2a\u6570\u7ec4，\u5373\u53ef\u53d6\u5f97\u76f8\u5173\u7684\u5ba2\u6237\u8fde\u63a5\u6570\u636e
\nstd::array<ClientData, USER_LIMIT + 1> m_users;
\nstd::array<int, PROCESS_LIMIT> m_subProcess;
\nint m_userCount = 0;<\/p>\n
\/\/ \u5f53\u7a0b\u5e8f\u6b63\u5728\u6b63\u5e38\u6267\u884c\u65f6，\u5373\u4f7f\u7a81\u7136\u88ab\u4fe1\u53f7\u6253\u65ad，\u8bfb\u53d6\u6216\u5199\u5165\u8fd9\u4e2a\u53d8\u91cf\u4e5f\u4e0d\u4f1a\u51fa\u73b0\u201c\u5199\u5230\u4e00\u534a\u201d\u7684\u60c5\u51b5\u3002
\nvolatile sig_atomic_t m_stopChild = 0; <\/p>\n
\u63a5\u4e0b\u6765\u662f\u4e00\u4e2a\u6bd4\u8f83\u5e38\u89c4\u7684\u64cd\u4f5c：（\u5982\u679c\u6709\u7591\u95ee，\u53ef\u4ee5\u770b\u4e00\u4e0b\u6211\u4e4b\u524d\u7684\u535a\u5ba2）<\/p>\n
int setNoBlocking(int fd) {
\n const int old_option = ::fcntl(fd, F_GETFL);
\n const int new_option = old_option | O_NONBLOCK;
\n fcntl(fd, F_SETFL, new_option);
\n return old_option;
\n}<\/p>\n
void addFd (int epollfd, int fd) {
\n epoll_event event;
\n event.data.fd = fd;
\n event.events = EPOLLIN | EPOLLET;
\n assert(::epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event) != -1);
\n setNoBlocking(fd);
\n}<\/p>\n
void removeFd(int epollfd, int fd) {
\n if (fd < 0) {
\n return;
\n }
\n ::epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, nullptr);
\n ::close(fd);
\n}<\/p>\n
void signalHandler(int sig) {
\n const int saveErrno = errno;
\n const char message = static_cast<char>(sig);
\n ::send(m_signalPipe[1], &message, 1, 0);
\n errno = saveErrno;
\n}<\/p>\n
void addSignal (int sig, void (*handler)(int), bool restart = true) {
\n struct sigaction sa;
\n sa.sa_handler = handler;
\n if (restart) {
\n sa.sa_flags = SA_RESTART;
\n }
\n ::sigfillset(&sa.sa_mask);
\n assert (::sigaction(sig, &sa, nullptr) != -1);
\n}<\/p>\n
\/\/ \u505c\u6b62\u4e00\u4e2a\u5b50\u8fdb\u7a0b
\nvoid childTermHandler(int) {
\n m_stopChild = 1;
\n}<\/p>\n
void closeFd(int& fd) {
\n if (fd >= 0) {
\n ::close(fd);
\n fd = -1;
\n }
\n}<\/p>\n
\u8fd9\u4e2a\u51fd\u6570\u662f\u4e3b\u8fdb\u7a0b\u91cc\u9762\u6700\u540e\u9500\u6bc1\u6240\u6709\u5185\u5b58\u7684\u51fd\u6570，\u9996\u5148\u6211\u4eec\u9700\u8981\u5173\u95ed\u6240\u6709\u5b58\u50a8\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26，\u5176\u5b9e\u4e3b\u8981\u5c31\u662f\u5173\u95ed[0]\u53f7\u7ba1\u9053，\u56e0\u4e3a\u4e3b\u8fdb\u7a0b\u53ea\u9760[0]\u53f7\u7ba1\u9053\u6765\u548c\u5bf9\u5e94\u7684\u8fdb\u7a0b\u901a\u4fe1，\u800c[1]\u53f7\u7ba1\u9053\u662f\u5728\u8fdb\u7a0b\u521b\u5efa\u7684\u65f6\u5019\u5c31\u5728\u4e3b\u8fdb\u7a0b\u91cc\u9762\u5173\u95ed\u4e86\u3002<\/p>\n
\u8fd8\u6709\u4e00\u4e2a\u91cd\u8981\u7684\u5c31\u662f\u6211\u4eec\u91ca\u653e\u5171\u4eab\u5185\u5b58\u7684\u51fd\u6570munmap，\u8fd9\u4e2a\u548cmmap\u662f\u4e00\u5bf9\u51fd\u6570，\u4e00\u4e2a\u662f\u521b\u5efa\u5171\u4eab\u5185\u5b58，\u4e00\u4e2a\u662f\u91ca\u653e\u5185\u5b58\u3002<\/p>\n
\u6700\u540e\u56e0\u4e3a\u6211\u4eec\u662f\u901a\u8fc7shm_open\u6253\u5f00POSIX\u5171\u4eab\u5185\u5b58\u7684\u5bf9\u8c61，\u6240\u4ee5\u6211\u4eec\u9700\u8981\u5173\u95edunlink<\/p>\n
void cleanResouces() {
\n for (int i = 0; i < m_userCount; i++) {
\n \/\/ \u662f\u5728\u7236\u8fdb\u7a0b\u4e2d\u6267\u884c\u7684，\u800c\u7236\u8fdb\u7a0b\u4fdd\u5b58\u7684\u662f\u6bcf\u4e2a socketpair \u7684 pipefd[0]（\u4e0e\u5bf9\u5e94\u5b50\u8fdb\u7a0b\u901a\u4fe1）
\n closeFd(m_users[i].pipefd[0]);
\n }<\/p>\n
closeFd(m_signalPipe[0]);
\n closeFd(m_signalPipe[1]);
\n closeFd(m_listened);
\n closeFd(m_epollfd);<\/p>\n
if (m_sharedMemory != nullptr && m_sharedMemory != MAP_FAILED) {
\n ::munmap(m_sharedMemory, USER_LIMIT * BUFFER_SIZE);
\n m_sharedMemory = nullptr;
\n }
\n ::shm_unlink(SHM_NAME);
\n} <\/p>\n
\u6211\u4eec\u5b50\u8fdb\u7a0b\u7684\u4f5c\u7528\u662f\u548c\u5ba2\u6237\u7aef\u5efa\u7acb\u8054\u7cfb\u5e76\u4e14\u901a\u4fe1，\u6240\u4ee5\u6211\u4eec\u6709\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u4e13\u95e8\u8fd0\u884c\u7684\u51fd\u6570\u3002\u6211\u4eec\u4f20\u5165\u7684\u53c2\u6570\u662f\u5ba2\u6237\u7aef\u5bf9\u5e94\u7684index，\u4ece\u800c\u901a\u8fc7\u6211\u4eec\u5b58\u50a8\u7684\u6570\u636e\u7d22\u5f15index，\u627e\u5230\u5bf9\u5e94\u7684socket\u7b49\u3002\u6bcf\u4e00\u4e2a\u8fdb\u7a0b\u90fd\u6709\u4e00\u4e2aepollfd，\u56e0\u4e3a\u8fd9\u4e2a\u662f\u4e13\u95e8\u548c\u7528\u6237\u8fdb\u884c\u76d1\u542c\u7684，\u540c\u65f6\u52a0\u5165\u4e86\u4e00\u4e2a\u9000\u51fa\u7684\u4fe1\u53f7，\u4ee5\u4fbf\u540e\u9762\u7ec8\u7aef\u7684\u9000\u51fa\u3002<\/p>\n
\u5bf9\u4e8e\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u6765\u8bf4，\u7ee7\u627f\u4e86\u7236\u8fdb\u7a0b\u7684\u8d44\u6e90，\u6240\u4ee5\u4e5f\u4f1a\u6709users\u7684\u6570\u636e<\/p>\n
\u5728while（）\u5faa\u73af\u91cc\u9762，\u5f53\u76d1\u542c\u5230\u4e86\u4e8b\u4ef6\u4e4b\u540e，\u5faa\u73af\u5904\u7406\u6bcf\u4e00\u4e2a\u4e8b\u4ef6，\u6211\u4eec\u5bf9\u6bcf\u4e00\u4e2a\u4e8b\u4ef6\u6709\u5206\u7c7b\u5904\u7406：<\/p>\n
\u5f53\u4e8b\u4ef6\u7684sockfd\u548c\u5b58\u50a8\u7684connfd\u76f8\u540c\u7684\u65f6\u5019，\u5c31\u8bf4\u660e\u662f\u8be5\u8fdb\u7a0b\u5bf9\u5e94\u7684\u5ba2\u6237\u6765\u6d88\u606f\u4e86，\u8fd9\u4e2a\u65f6\u5019\u5c31\u8981recv\u6d88\u606f，\u4e0d\u8fc7\u6211\u4eec\u662f\u4e00\u4e2a\u5171\u4eab\u5185\u5b58，\u6240\u4ee5\u6211\u4eec\u4e0d\u662f\u5f00\u8f9f\u5185\u5b58，\u800c\u662f\u76f4\u63a5\u5229\u7528\u5171\u4eab\u5185\u5b58，\u6bcf\u4e2a\u8fdb\u7a0b\u5bf9\u5e94\u7684\u5171\u4eab\u5185\u5b58\u7684\u5730\u65b9\u662f\u786e\u5b9a\u7684，\u5730\u5740\u662fm_sharedMemory + index * BUFFER_SIZE，\u7136\u540e\u628a\u63a5\u53d7\u5230\u7684\u6570\u636e\u653e\u5728\u8fd9\u91cc\u9762\u3002\u5728\u63a5\u53d7\u5b8c\u4fe1\u606f\u4e86\u4e4b\u540e，\u53d1\u9001\u6d88\u606f\u7ed9\u4e3b\u8fdb\u7a0b（\u670d\u52a1\u5668\u7aef），send\u7684\u662fclient\u7684\u7f16\u53f7，\u8fd9\u6837\u5b50\u4e3b\u8fdb\u7a0b（\u670d\u52a1\u5668\u7aef）\u5c31\u53ef\u4ee5\u77e5\u9053\u662f\u54ea\u4e00\u4e2a\u8fdb\u7a0b（\u4e5f\u5c31\u662f\u5bf9\u5e94\u7684\u5ba2\u6237\u7aef）\u3002\u53ef\u80fd\u6709\u4eba\u4f1a\u7591\u95ee，\u90a3\u4e3a\u4ec0\u4e48\u4e0d\u53d1\u9001\u63a5\u6536\u5230\u5ba2\u6237\u7aef\u7684\u6d88\u606f\u5462？\u539f\u56e0\u5c31\u662f\u8fd9\u4e2a\u662f\u5171\u4eab\u5185\u5b58，\u6211\u4eec\u53ea\u9700\u8981\u77e5\u9053\u53d1\u6d88\u606f\u5bf9\u5e94\u8fdb\u7a0b\u6240\u5c5e\u7684\u5730\u5740，\u8fd9\u4e2a\u6837\u5b50\u76f4\u63a5\u53ef\u4ee5\u53d6\u6570\u636e\u4e86，\u6240\u4ee5\u6211\u4eec\u4f20\u9012\u7684\u90fd\u662findex\u3002<\/p>\n
\u5f53\u4e8b\u4ef6\u7684sockfd\u548c\u7236\u8fdb\u7a0b\u901a\u4fe1\u7684\u7ba1\u9053\u4e00\u6837\u7684\u65f6\u5019，\u8bf4\u660e\u662f\u63a5\u6536\u5230\u4e86\u7236\u8fdb\u7a0b\u7684\u6d88\u606f，\u4e5f\u5c31\u662f\u5e7f\u64ad，\u8fd9\u4e2a\u65f6\u5019\u6211\u4eec\u63a5\u53d7\u5230\u4e86client\u7684index，\u7136\u540e\u5c31\u53ef\u4ee5\u627e\u5230\u5bf9\u5e94\u7684\u5171\u4eab\u5185\u5b58\u4f4d\u7f6e，\u7136\u540e\u53d1\u9001\u7ed9\u5ba2\u6237\u7aef\u3002<\/p>\n
\/\/ \u5b50\u8fdb\u7a0b\u8fd0\u884c\u7684\u51fd\u6570，\u53c2\u6570index\u6307\u51fa\u8be5\u5b50\u8fdb\u7a0b\u5904\u7406\u7684\u5ba2\u6237\u8fde\u63a5\u7684\u7f16\u53f7
\nvoid runChild(int index) {
\n std::array<epoll_event, MAX_EVENT_NUMBER> events;
\n const int childEpollfd = ::epoll_create(1);
\n assert(childEpollfd != -1);<\/p>\n
const int connfd = m_users[index].connfd;
\n const int pipefd = m_users[index].pipefd[1]; \/\/ \u5b50\u8fdb\u7a0b\u7684socket<\/p>\n
addSignal(SIGTERM, childTermHandler, false);<\/p>\n
while(!m_stopChild) {
\n const int number = ::epoll_wait(childEpollfd, events.data(), MAX_EVENT_NUMBER, -1);<\/p>\n
if (number < 0 && errno != EINTR) {
\n std::cerr << "child epoll_wait failed:" << std::strerror(errno) << std::endl;
\n break;
\n }<\/p>\n
for (int i = 0; i < number; i++) {
\n const int sockfd = events[i].data.fd;
\n \/\/ \u672c\u5b50\u8fdb\u7a0b\u8d1f\u8d23\u7684\u5ba2\u6237\u8fde\u63a5\u6709\u6570\u636e\u5230\u8fbe，\u5199\u5230\u672c\u5ba2\u6237\u7aef\u5bf9\u5e94\u7684\u5171\u4eab\u5185\u5b58\u64cd\u4f5c
\n \/\/ \u518d\u628a\u5ba2\u6237\u7f16\u53f7\u901a\u77e5\u7ed9\u7236\u8fdb\u7a0b
\n if (sockfd == connfd && (events[i].events & EPOLLIN)) {
\n char* buffer = m_sharedMemory + index * BUFFER_SIZE;
\n std::memset(buffer, 0, BUFFER_SIZE);<\/p>\n
int received = ::recv(connfd, buffer, BUFFER_SIZE – 1, 0);
\n if (received < 0) {
\n if (errno != EAGAIN && errno != EWOULDBLOCK) {
\n m_stopChild = 1;
\n }
\n }
\n else if(received == 0) {
\n m_stopChild = 1;
\n }
\n else {
\n \/\/ \u4f20\u9012\u7b2c\u51e0\u4e2a\u5ba2\u6237
\n ::send(pipefd, &index, sizeof(index), 0);
\n }
\n }
\n \/\/ \u7236\u8fdb\u7a0b\u901a\u77e5\u672c\u8fdb\u7a0b（\u901a\u8fc7\u7ba1\u9053）\u5c06\u7b2cclient\u4e2a\u5ba2\u6237\u7684\u6570\u636e\u53d1\u9001\u5230\u672c\u8fdb\u7a0b\u8d1f\u8d23\u7684\u5ba2\u6237\u7aef
\n else if (sockfd == pipefd && (events[i].events & EPOLLIN)) {
\n int client = -1;
\n int received = ::recv(pipefd, &client, sizeof(client), 0);<\/p>\n
if (received < 0) {
\n if (errno != EAGAIN && errno != EWOULDBLOCK) {
\n m_stopChild = 1;
\n }
\n }
\n else if(received == 0) {
\n m_stopChild = 1;
\n }
\n else if (received == static_cast<ssize_t>(sizeof(client)) && client >= 0 && client < USER_LIMIT) {
\n \/\/ \u76f4\u63a5\u4f7f\u7528\u5171\u4eab\u5185\u5b58，\u53d1\u9001\u7ed9\u5bf9\u5e94\u7684\u5ba2\u6237\u7aef
\n ::send(connfd, m_sharedMemory + client * BUFFER_SIZE, BUFFER_SIZE, 0);
\n }
\n }
\n }
\n }<\/p>\n
::close(connfd);
\n ::close(pipefd);
\n ::close(childEpollfd);
\n} <\/p>\n
\u5f53\u5ba2\u6237\u7aef\u5173\u95ed\u4e86\u4e4b\u540e，\u6211\u4eec\u5220\u9664\u5ba2\u6237\u7aef\u7684\u4e00\u5207\u6570\u636e\u3002\u8fd9\u4e2a\u662f\u5728\u7236\u8fdb\u7a0b\u91cc\u9762\u8c03\u7528\u7684，\u6240\u4ee5\u8981\u79fb\u9664\u4e0e\u5b50\u8fdb\u7a0b\u7684\u901a\u4fe1socket\u3002\u5e76\u4e14\u6211\u4eec\u7684\u6570\u7ec4\u6392\u5217\u4e00\u5b9a\u8981\u662f\u8fde\u7eed\u7684，\u5426\u5219\u591a\u6b21\u5173\u95ed\u8fde\u63a5\u4e4b\u540e\u4f1a\u6d6a\u8d39\u5f88\u591a\u7684\u5185\u5b58\u3002\u6240\u4ee5\u5f53\u6211\u4eec\u5220\u9664\u4e86\u4e2d\u95f4\u4e00\u4e2aindex，\u90a3\u4e48\u6211\u4eec\u8981\u628a\u6700\u540e\u4e00\u4e2a\u586b\u8865\u5230\u6211\u4eec\u5220\u9664\u7684\u5730\u65b9，\u5305\u62ecpid<\/p>\n
void eraseUser (int index) {
\n if (index < 0 || index >= m_userCount) {
\n return;
\n }<\/p>\n
\/\/ \u79fb\u9664\u7236\u8fdb\u7a0b\u4e3a\u6bcf\u4e2a\u5b50\u8fdb\u7a0b\u4fdd\u7559\u7684\u901a\u4fe1\u7ba1\u9053
\n removeFd(m_epollfd, m_users[index].pipefd[0]);<\/p>\n
const int last = m_userCount – 1;
\n if (index != last) {
\n m_users[index] = m_users[last];
\n const pid_t movedPid = m_users[index].pid;
\n if (movedPid >= 0 && movedPid < PROCESS_LIMIT) {
\n m_subProcess[static_cast<int>(movedPid)] = index;
\n }
\n }
\n m_userCount–;
\n} <\/p>\n
\u5bf9\u4e8e\u5171\u4eab\u5185\u5b58，\u6211\u4eec\u7684\u4e00\u7cfb\u5217\u64cd\u4f5c\u5c31\u662f：<\/p>\n
\u5148shm_open\u6253\u5f00\u5171\u4eab\u5185\u5b58\u7684\u5bf9\u8c61，\u5176\u8fd4\u56de\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u5f88\u5173\u952e，\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u8fd9\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u91cd\u6784\u5185\u5b58\u7684\u5927\u5c0f，\u901a\u8fc7ftruncate（）\u51fd\u6570，\u6700\u540e\u901a\u8fc7mmap（）\u521b\u5efa\u6211\u4eec\u7684\u5171\u4eab\u5185\u5b58\u5e76\u8fd4\u56de\u8fd9\u5757\u5185\u5b58\u7684\u6307\u9488\u3002\u4e00\u5207\u7ed3\u675f\u4e86\u4e4b\u540e\u5c31\u53ef\u4ee5\u5173\u95ed\u8fd9\u4e2a\u6253\u5f00\u5171\u4eab\u5185\u5b58\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n
std::array<epoll_event, MAX_EVENT_NUMBER> events;
\n m_epollfd = epoll_create(1);
\n assert(m_epollfd == -1);
\n addFd(m_epollfd, m_listened);<\/p>\n
assert (::socketpair(AF_UNIX, SOCK_STREAM, 0, m_signalPipe.data()));
\n setNoBlocking(m_signalPipe[1]);
\n addFd(m_epollfd, m_signalPipe[0]);<\/p>\n
addSignal(SIGCHLD, signalHandler);
\n addSignal(SIGTERM, signalHandler);
\n addSignal(SIGINT, signalHandler);
\n addSignal(SIGPIPE, SIG_IGN);<\/p>\n
bool stopServer = false;
\n bool terminating = false;<\/p>\n
const int shmfd = ::shm_open(SHM_NAME, O_CREAT | O_RDWR, 0666);
\n assert(shmfd != -1);
\n \/\/ \u901a\u8fc7\u6587\u4ef6\u63cf\u8ff0\u7b26\u4fee\u6539\u6587\u4ef6\u6216\u5171\u4eab\u5185\u5b58\u5bf9\u8c61\u7684\u5927\u5c0f
\n assert(::ftruncate(shmfd, USER_LIMIT * BUFFER_SIZE) != -1);<\/p>\n
m_sharedMemory = static_cast<char*>(::mmap(nullptr, USER_LIMIT * BUFFER_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0));
\n ::close(shmfd); <\/p>\n
\u5728while（）\u91cc\u9762，\u6211\u4eec\u89e3\u51b3\u7684\u5c31\u662f\u51e0\u4e2a\u95ee\u9898：<\/p>\n
1\u3001\u5982\u679c\u6709\u8fde\u63a5\u53d1\u6765，\u5b58\u50a8\u5bf9\u5e94\u7684\u6570\u636e，\u521b\u5efa\u5bf9\u5e94\u7684\u7ba1\u9053，\u7136\u540e\u521b\u5efa\u5bf9\u5e94\u7684\u5b50\u8fdb\u7a0b，\u5728\u5b50\u8fdb\u7a0b\u91cc\u9762\u53ea\u4fdd\u7559\u548c\u7236\u8fdb\u7a0b\u901a\u4fe1\u7684socket\u548c\u5ba2\u6237\u7aef\u901a\u4fe1\u7684socket，\u5176\u4ed6\u5168\u90e8\u5173\u95ed，\u5982\u679c\u7ed3\u675f\u4e86\u5b50\u8fdb\u7a0b，\u5c31\u8981munmap\u5176\u5171\u4eab\u5185\u5b58\u7684\u90e8\u5206\u3002\u800c\u7236\u8fdb\u7a0b\u8981\u505a\u7684\u4e8b\u60c5\u5c31\u662f\u5b58\u50a8\u5b50\u8fdb\u7a0b\u7684\u4fe1\u606f，\u4e0d\u8fc7\u6211\u4eec\u8fdb\u7a0b\u6570\u91cf\u90fd\u662f\u6709\u9650\u7684，\u6240\u4ee5\u5f53\u6211\u4eec\u521b\u5efa\u4e86\u5b50\u8fdb\u7a0b\u4e4b\u540e\u8981\u5224\u65ad\u5982\u679c\u8d85\u8fc7\u4e86\u8fd9\u4e2a\u4e0a\u9650，\u90a3\u4e48\u5c31\u8981\u5173\u95ed\u3002<\/p>\n
2\u3001\u5f53\u6709\u4fe1\u53f7\u5230\u6765\u7684\u65f6\u5019，\u5982\u679c\u662f\u5b50\u8fdb\u7a0b\u9000\u51fa\u7684\u4fe1\u53f7，\u7236\u8fdb\u7a0b\u975e\u963b\u585e\u56de\u6536，\u56e0\u4e3a\u6709\u4fe1\u53f7\u6765\u4e86\u4e00\u5b9a\u662f\u53ef\u4ee5\u56de\u6536\u7684，\u800c\u975e\u963b\u585e\u56de\u6536\u7684\u7279\u70b9\u5c31\u662f\u9ad8\u6548\u3002\u5982\u679c\u662f\u7236\u8fdb\u7a0b\u88ab\u5173\u95ed\u7684\u4fe1\u53f7\u6765\u4e86，\u90a3\u4e48\u8981\u5173\u95ed\u6240\u6709\u7684\u5b50\u8fdb\u7a0b\u3002<\/p>\n
3\u3001\u901a\u8fc7\u5e7f\u64ad\u53d1\u9001\u4fe1\u606f，\u5176\u5b9e\u5c31\u662f\u4f20\u9012\u5bf9\u5e94\u7684index，\u8ba9\u5b50\u8fdb\u7a0b\u91cc\u9762\u8fd0\u884c\u7684\u51fd\u6570\u63a5\u53d7index，\u81ea\u5df1\u8bfb\u53d6\u5171\u4eab\u5185\u5b58\u91cc\u9762\u7684\u6570\u636e\u3002<\/p>\n
while (!stopServer) {
\n const int number = epoll_wait(m_epollfd, events.data(), MAX_EVENT_NUMBER, -1);
\n if (number < 0 && errno != EINTR) {
\n std::cerr << "epoll_wait failed: "
\n << std::strerror(errno) << '\\\\n';
\n break;
\n }<\/p>\n
for (int i = 0; i < number; i++) {
\n const int sockfd = events[i].data.fd;
\n if (sockfd == m_listened && (events[i].events & EPOLLIN)) {
\n sockaddr_in clientAddress;
\n socklen_t len = sizeof(clientAddress);
\n const int connfd = ::accept(m_listened, (sockaddr*)&clientAddress, &len);
\n if (connfd < 0) {
\n if (errno != EAGAIN && errno != EWOULDBLOCK) {
\n std::cerr << "accept failed:" << std::strerror(errno) << std::endl;
\n }
\n continue;
\n } <\/p>\n
if (m_userCount >= USER_LIMIT) {
\n const std::string message = "too many users\\\\n";
\n std::cerr << message;
\n ::send(connfd, message.data(), message.size(), 0);
\n ::close(connfd);
\n continue;
\n }<\/p>\n
const int index = m_userCount;
\n m_users[index].address = clientAddress;
\n m_users[index].connfd = connfd;
\n assert(::socketpair(AF_UNIX, SOCK_STREAM, 0, m_users[index].pipefd.data()) != -1);<\/p>\n
const pid_t pid = ::fork();
\n \/\/ fork\u5931\u8d25\u5566
\n if (pid < 0) {
\n ::close(connfd);
\n ::close(m_users[index].pipefd[0]);
\n ::close(m_users[index].pipefd[1]);
\n continue;
\n }<\/p>\n
if (pid == 0) {
\n ::close(m_epollfd);
\n ::close(m_listened);
\n ::close(m_users[index].pipefd[0]);
\n ::close(m_signalPipe[0]);
\n ::close(m_signalPipe[1]);<\/p>\n
runChild(index);
\n ::munmap(m_sharedMemory, USER_LIMIT * BUFFER_SIZE);
\n _exit(EXIT_SUCCESS);
\n }<\/p>\n
::close(connfd);
\n ::close(m_users[index].pipefd[1]);
\n m_users[index].pipefd[1] = -1;
\n addFd (m_epollfd, m_users[index].pipefd[0]);<\/p>\n
m_users[index].pid = pid;
\n if (pid >= PROCESS_LIMIT) {
\n std::cerr << "child PID exceeds PROCESS_LIMIT\\\\n";
\n ::kill(pid, SIGTERM);
\n removeFd(m_epollfd, m_users[index].pipefd[0]);
\n continue;
\n }
\n m_subProcess[static_cast<int>(pid)] = index;
\n m_userCount++;
\n }
\n \/\/ \u7edf\u4e00\u4fe1\u53f7\u6e90，\u4ece\u4fe1\u53f7\u7ba1\u9053\u8bfb\u53d6\u4fe1\u53f7\u7f16\u53f7
\n else if (sockfd == m_signalPipe[0] && (events[i].events & EPOLLIN)) {
\n std::array<char, 1024> signals;
\n int received = ::recv(m_signalPipe[0], signals.data(), signals.size(), 0);
\n if (received <= 0) {
\n continue;
\n }<\/p>\n
for (int j = 0; j < received; j++) {
\n switch (signals[j])
\n {
\n case SIGCHLD:
\n while(true) {
\n int status = 0;
\n const pid_t pid = ::waitpid(-1, &status, WNOHANG);
\n if (pid <= 0) {
\n break;
\n }
\n if (pid < PROCESS_LIMIT) {
\n const int index = m_subProcess[pid];
\n m_subProcess[pid] = -1;
\n eraseUser(index);
\n }
\n }
\n if (terminating && m_userCount == 0) {
\n stopServer = true;
\n }
\n break;
\n case SIGTERM:
\n case SIGINT:
\n if (m_userCount == 0) {
\n stopServer = true;
\n }
\n else {
\n for (int k = 0; k < m_userCount; k++) {
\n ::kill(m_users[k].pid, SIGTERM);
\n }
\n terminating = true;
\n }
\n break;
\n default:
\n break;
\n }
\n }
\n }
\n \/\/ \u67d0\u4e2a\u5b50\u8fdb\u7a0b\u5199\u5165\u4e86\u5171\u4eab\u5185\u5b58；\u901a\u8fc7\u5e7f\u64ad\u5e7f\u64ad\u7ed9\u5176\u4ed6\u5b50\u8fdb\u7a0b
\n else if (events[i].events & EPOLLIN) {
\n int child = -1;
\n const int received = ::recv(sockfd, &child, sizeof(child), 0);
\n if (received <= 0) {
\n continue;
\n }<\/p>\n
for (int j = 0; j < m_userCount; j++) {
\n if (m_users[j].pipefd[0] == sockfd) {
\n continue;
\n }
\n ::send(m_users[j].pipefd[0], &child, sizeof(child), 0);
\n }
\n }
\n }
\n }
\n cleanResouces(); <\/p>\n
\u6240\u4ee5\u5171\u4eab\u5185\u5b58\u7684\u804a\u5929\u5ba4\u6700\u5927\u7684\u4f18\u70b9\u5c31\u662f\u4e0d\u9700\u8981send\u4fe1\u606f，\u51cf\u5c11\u4e86\u62f7\u8d1d\u7684\u5f00\u9500，\u800c\u662f\u4ec5\u4ec5\u8bfb\u53d6\u5171\u4eab\u5185\u5b58\u7684\u6570\u636e，\u8fd9\u4e2a\u5bf9\u4e8e\u6027\u80fd\u6709\u5f88\u5927\u7684\u63d0\u9ad8\u3002<\/p>\n
\u672c\u7bc7\u6587\u7ae0\u5230\u8fd9\u91cc\u5c31\u7ed3\u675f\u4e86！！！\u5e0c\u671b\u53ef\u4ee5\u5e2e\u52a9\u5927\u5bb6\u7406\u89e3~~~<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f15\u8a00
\n\u672c\u7bc7\u53c2\u8003\u4e66\u76ee\u300aLinux\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u7f16\u7a0b\u300b，\u8fd9\u662f\u6211\u7b2c\u4e09\u6b21\u5b9e\u73b0\u7f51\u7edc\u804a\u5929\u5ba4，\u8fd9\u4e00\u6b21\u662f\u5728\u5185\u5b58\u7684\u65b9\u9762\u8fdb\u884c\u4e86\u6781\u5927\u7684\u6539\u8fdb，\u5e76\u4e14\u672c\u7bc7\u6587\u7ae0\u4e3b\u8981\u4f7f\u7528c11\u6765\u5b9e\u73b0\u7684，\u5c06\u4e66\u672c\u91cc\u9762\u7684c\u8bed\u8a00\u91cd\u5199\u4e86\u4e00\u904d\u3002
\n\u4ee3\u7801\u5df2\u7ecf\u4e0a\u4f20\u5230\u4e86github\u4e0a\u9762，fengyue05\/Linux-: \u672c\u4ed3\u5e93\u91cc\u9762\u4f1a\u6709\u5173\u4e8e\u300aLinux\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u7f16\u7a0b\u300b\u7684\u4e00\u4e9b\u4e3b\u8981\u4ee3\u7801\u5b9e\u73b0
\n\u4ee3\u7801
\n\u5728\u5f00\u59cb\u771f\u6b63\u4ee3\u7801\u7684\u5b9e\u73b0\u524d\u9762，\u6211\u4eec\u9700\u8981\u51c6\u5907\u4e00\u4e9b\u53d8\u91cf，<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[55,58,43,78,396],"topic":[],"class_list":["post-96601","post","type-post","status-publish","format-standard","hentry","category-server","tag-c","tag-linux","tag-43","tag-78","tag-396"],"yoast_head":"\n