0000

server-exp4/cache.c

@@ -0,0 +1,311 @@
+/**
+ * cache.c — LRU 缓存实现
+ *
+ * 实现细节:
+ *   1. 使用 DJB2 哈希算法将 URL 映射到桶索引
+ *   2. 双向链表 (head↔...↔tail) 维护访问顺序:
+ *      - head 方向是最近使用 (MRU)
+ *      - tail 方向是最久未使用 (LRU)
+ *   3. 查找命中时，将节点移动到链表头部
+ *   4. 插入满时，淘汰链表尾部的 LRU 节点
+ *   5. 线程安全: 所有操作使用 pthread_mutex 保护
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include "cache.h"
+
+/* ======================== 内部常量 ======================== */
+
+#define DEFAULT_NUM_BUCKETS  101   /* 哈希桶数量 (质数，减少冲突) */
+#define MAX_CACHE_SIZE       1024  /* 默认最大条目数 */
+
+/* ======================== 内部辅助函数 ======================== */
+
+/**
+ * hash_url — DJB2 哈希算法
+ * 该算法简单高效，分布均匀，适合字符串键
+ */
+static unsigned long hash_url(const char *url)
+{
+    unsigned long hash = 5381;
+    int c;
+    while ((c = *url++))
+        hash = ((hash << 5) + hash) + c;  /* hash * 33 + c */
+    return hash;
+}
+
+/**
+ * list_remove — 从双向链表中移除节点 (不释放内存)
+ */
+static void list_remove(cache_t *cache, cache_entry_t *entry)
+{
+    if (entry->prev)
+        entry->prev->next = entry->next;
+    else
+        cache->head = entry->next;  /* 移除的是头节点 */
+
+    if (entry->next)
+        entry->next->prev = entry->prev;
+    else
+        cache->tail = entry->prev;  /* 移除的是尾节点 */
+}
+
+/**
+ * list_add_head — 将节点添加到链表头部 (MRU 位置)
+ */
+static void list_add_head(cache_t *cache, cache_entry_t *entry)
+{
+    entry->prev = NULL;
+    entry->next = cache->head;
+    if (cache->head)
+        cache->head->prev = entry;
+    else
+        cache->tail = entry;  /* 链表为空，也是尾节点 */
+    cache->head = entry;
+}
+
+/**
+ * evict_lru — 淘汰 LRU 节点 (链表尾部)
+ * 从哈希表和链表中移除，释放内存
+ */
+static void evict_lru(cache_t *cache)
+{
+    if (cache->tail == NULL)
+        return;
+
+    cache_entry_t *victim = cache->tail;
+
+    /* 从链表中移除 */
+    list_remove(cache, victim);
+
+    /* 从哈希桶中移除 */
+    unsigned long h = hash_url(victim->url) % cache->num_buckets;
+    cache_entry_t **pp = &cache->buckets[h];
+    while (*pp) {
+        if (*pp == victim) {
+            *pp = victim->hnext;
+            break;
+        }
+        pp = &(*pp)->hnext;
+    }
+
+    /* 释放内存 */
+    free(victim->url);
+    free(victim->data);
+    free(victim);
+
+    cache->cur_size--;
+    cache->evictions++;
+}
+
+/* ======================== 公开 API 实现 ======================== */
+
+/**
+ * cache_init — 初始化 LRU 缓存
+ */
+cache_t *cache_init(int max_size)
+{
+    cache_t *cache = (cache_t *)calloc(1, sizeof(cache_t));
+    if (cache == NULL) {
+        perror("cache_init: calloc failed");
+        return NULL;
+    }
+
+    cache->num_buckets = DEFAULT_NUM_BUCKETS;
+    cache->max_size = (max_size > 0 && max_size <= MAX_CACHE_SIZE)
+                      ? max_size : MAX_CACHE_SIZE;
+    cache->cur_size = 0;
+    cache->head = NULL;
+    cache->tail = NULL;
+    cache->hits = 0;
+    cache->misses = 0;
+    cache->evictions = 0;
+    cache->bytes_served = 0;
+
+    cache->buckets = (cache_entry_t **)calloc(cache->num_buckets,
+                                              sizeof(cache_entry_t *));
+    if (cache->buckets == NULL) {
+        perror("cache_init: calloc buckets failed");
+        free(cache);
+        return NULL;
+    }
+
+    if (pthread_mutex_init(&cache->lock, NULL) != 0) {
+        perror("cache_init: mutex_init failed");
+        free(cache->buckets);
+        free(cache);
+        return NULL;
+    }
+
+    printf("[Cache] 初始化完成: 最大条目=%d, 桶数量=%d\n",
+           cache->max_size, cache->num_buckets);
+    return cache;
+}
+
+/**
+ * cache_lookup — 在缓存中查找 URL (O(1) 平均)
+ *
+ * 流程:
+ *   1. 计算哈希值，定位桶
+ *   2. 遍历桶内冲突链查找匹配 URL
+ *   3. 命中: 将条目移到链表头部 (标记为最近使用)，拷贝数据
+ *   4. 未命中: 返回 0
+ */
+int cache_lookup(cache_t *cache, const char *url,
+                 char **data, long *size, char *filetype)
+{
+    if (cache == NULL || url == NULL)
+        return 0;
+
+    pthread_mutex_lock(&cache->lock);
+
+    unsigned long h = hash_url(url) % cache->num_buckets;
+    cache_entry_t *entry = cache->buckets[h];
+
+    while (entry) {
+        if (strcmp(entry->url, url) == 0) {
+            /* 缓存命中: 移动到链表头部 */
+            list_remove(cache, entry);
+            list_add_head(cache, entry);
+
+            /* 更新访问时间 */
+            clock_gettime(CLOCK_MONOTONIC, &entry->timestamp);
+
+            /* 拷贝数据给调用者 */
+            *size = entry->size;
+            strcpy(filetype, entry->filetype);
+            *data = (char *)malloc(entry->size);
+            if (*data)
+                memcpy(*data, entry->data, entry->size);
+
+            cache->hits++;
+            cache->bytes_served += entry->size;
+
+            pthread_mutex_unlock(&cache->lock);
+            return 1;
+        }
+        entry = entry->hnext;
+    }
+
+    /* 缓存未命中 */
+    cache->misses++;
+    pthread_mutex_unlock(&cache->lock);
+    return 0;
+}
+
+/**
+ * cache_insert — 向缓存插入新条目
+ *
+ * 流程:
+ *   1. 若缓存已满，先淘汰 LRU 条目
+ *   2. 创建新条目，拷贝数据
+ *   3. 添加到哈希表和链表头部
+ */
+int cache_insert(cache_t *cache, const char *url,
+                 const char *data, long size, const char *filetype)
+{
+    if (cache == NULL || url == NULL || data == NULL || size <= 0)
+        return -1;
+
+    pthread_mutex_lock(&cache->lock);
+
+    /* 检查是否已存在 (更新) */
+    unsigned long h = hash_url(url) % cache->num_buckets;
+    cache_entry_t *entry = cache->buckets[h];
+    while (entry) {
+        if (strcmp(entry->url, url) == 0) {
+            /* 已存在: 更新数据和位置 */
+            free(entry->data);
+            entry->data = (char *)malloc(size);
+            if (entry->data == NULL) {
+                pthread_mutex_unlock(&cache->lock);
+                return -1;
+            }
+            memcpy(entry->data, data, size);
+            entry->size = size;
+            strcpy(entry->filetype, filetype);
+            clock_gettime(CLOCK_MONOTONIC, &entry->timestamp);
+
+            /* 移动到头部 */
+            list_remove(cache, entry);
+            list_add_head(cache, entry);
+            pthread_mutex_unlock(&cache->lock);
+            return 0;
+        }
+        entry = entry->hnext;
+    }
+
+    /* 缓存已满，淘汰 LRU */
+    while (cache->cur_size >= cache->max_size)
+        evict_lru(cache);
+
+    /* 创建新条目 */
+    cache_entry_t *new_entry = (cache_entry_t *)calloc(1, sizeof(cache_entry_t));
+    if (new_entry == NULL) {
+        pthread_mutex_unlock(&cache->lock);
+        return -1;
+    }
+
+    new_entry->url = strdup(url);
+    new_entry->data = (char *)malloc(size);
+    if (new_entry->url == NULL || new_entry->data == NULL) {
+        free(new_entry->url);
+        free(new_entry->data);
+        free(new_entry);
+        pthread_mutex_unlock(&cache->lock);
+        return -1;
+    }
+
+    memcpy(new_entry->data, data, size);
+    new_entry->size = size;
+    strcpy(new_entry->filetype, filetype);
+    clock_gettime(CLOCK_MONOTONIC, &new_entry->timestamp);
+
+    /* 添加到哈希桶 */
+    new_entry->hnext = cache->buckets[h];
+    cache->buckets[h] = new_entry;
+
+    /* 添加到链表头部 */
+    list_add_head(cache, new_entry);
+    cache->cur_size++;
+
+    pthread_mutex_unlock(&cache->lock);
+    return 0;
+}
+
+/**
+ * cache_free — 释放所有缓存资源
+ */
+void cache_free(cache_t *cache)
+{
+    if (cache == NULL) return;
+
+    pthread_mutex_lock(&cache->lock);
+
+    /* 遍历链表释放所有条目 */
+    cache_entry_t *entry = cache->head;
+    while (entry) {
+        cache_entry_t *next = entry->next;
+        free(entry->url);
+        free(entry->data);
+        free(entry);
+        entry = next;
+    }
+
+    free(cache->buckets);
+    pthread_mutex_unlock(&cache->lock);
+    pthread_mutex_destroy(&cache->lock);
+
+    printf("[Cache] 释放完成: 命中=%lld 未命中=%lld 淘汰=%lld "
+           "命中率=%.1f%% 服务字节=%lld\n",
+           cache->hits, cache->misses, cache->evictions,
+           cache->hits + cache->misses > 0
+               ? 100.0 * cache->hits / (cache->hits + cache->misses)
+               : 0.0,
+           cache->bytes_served);
+
+    free(cache);
+}

server-exp4/cache.h

@@ -0,0 +1,92 @@
+/**
+ * cache.h — Web服务器 LRU 缓存模块
+ *
+ * 设计思想:
+ *   使用 哈希表 + 双向链表 实现 O(1) 的查找、插入和淘汰操作。
+ *   哈希表提供快速键值查找，双向链表维护 LRU 访问顺序。
+ *   最近被访问的节点移动到链表头部 (MRU位置)，
+ *   链表尾部的节点是最久未被访问的 (LRU位置)，淘汰时优先移除。
+ *
+ * 数据结构:
+ *   cache_entry: 单个缓存条目 (文件名、文件内容、大小、MIME类型、时间戳)
+ *   cache_t:      缓存管理器 (哈希表桶数组、链表头尾、统计计数器)
+ *
+ * 主要操作:
+ *   cache_init(max_size):  初始化缓存，设置最大条目数
+ *   cache_lookup(url, buf, size, type): 查找缓存，命中时拷贝数据并返回 1
+ *   cache_insert(url, data, size, type): 插入缓存，必要时淘汰 LRU 条目
+ *   cache_free():           释放所有缓存内存
+ */
+
+#ifndef _CACHE_H_
+#define _CACHE_H_
+
+#include <time.h>
+#include <pthread.h>
+
+/* 缓存条目 */
+typedef struct cache_entry {
+    char *url;                  /* 请求 URL (作为键) */
+    char *data;                 /* 文件内容 */
+    long size;                  /* 文件大小 */
+    char filetype[64];          /* MIME 类型 */
+    struct timespec timestamp;  /* 最后访问时间 */
+    struct cache_entry *prev;   /* 双向链表前驱 */
+    struct cache_entry *next;   /* 双向链表后继 */
+    struct cache_entry *hnext;  /* 哈希桶内链表 (冲突链) */
+} cache_entry_t;
+
+/* 缓存管理器 */
+typedef struct {
+    cache_entry_t **buckets;    /* 哈希桶数组 */
+    int num_buckets;            /* 哈希桶数量 */
+    int max_size;               /* 最大条目数 */
+    int cur_size;               /* 当前条目数 */
+    cache_entry_t *head;        /* LRU 链表头 (最近使用) */
+    cache_entry_t *tail;        /* LRU 链表尾 (最久未使用) */
+    pthread_mutex_t lock;       /* 线程安全锁 */
+
+    /* 统计信息 */
+    long long hits;             /* 缓存命中次数 */
+    long long misses;           /* 缓存未命中次数 */
+    long long evictions;        /* 淘汰次数 */
+    long long bytes_served;     /* 从缓存服务的字节数 */
+} cache_t;
+
+/**
+ * cache_init — 初始化 LRU 缓存
+ * @max_size: 最大缓存条目数
+ * @return: 指向 cache_t 的指针，失败返回 NULL
+ */
+cache_t *cache_init(int max_size);
+
+/**
+ * cache_lookup — 在缓存中查找 URL
+ * @cache:    缓存管理器指针
+ * @url:      请求的 URL 键
+ * @data:     输出参数，命中时指向缓存数据的拷贝 (调用者需 free)
+ * @size:     输出参数，数据大小
+ * @filetype: 输出参数，MIME 类型
+ * @return:   1=命中, 0=未命中
+ */
+int cache_lookup(cache_t *cache, const char *url,
+                 char **data, long *size, char *filetype);
+
+/**
+ * cache_insert — 向缓存插入新条目
+ * @cache:    缓存管理器指针
+ * @url:      URL 键
+ * @data:     文件内容 (缓存会拷贝一份)
+ * @size:     文件大小
+ * @filetype: MIME 类型
+ * @return:   0=成功, -1=失败
+ */
+int cache_insert(cache_t *cache, const char *url,
+                 const char *data, long size, const char *filetype);
+
+/**
+ * cache_free — 释放所有缓存资源
+ */
+void cache_free(cache_t *cache);
+
+#endif /* _CACHE_H_ */

server-exp4/cgi-bin/add.c

@@ -0,0 +1,63 @@
+/*
+ * cgi-bin/add.c — 简单CGI加法计算器
+ *
+ * 用于测试Web服务器的CGI功能
+ * GET: /cgi-bin/add?a=10&b=20
+ * POST: 提交表单到 /cgi-bin/add
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(void)
+{
+    char *query = getenv("QUERY_STRING");
+    char *method = getenv("REQUEST_METHOD");
+
+    printf("Content-Type: text/html; charset=UTF-8\r\n\r\n");
+    printf("<!DOCTYPE html>\n<html><head>\n");
+    printf("<meta charset=\"UTF-8\">\n");
+    printf("<title>CGI Calculator</title>\n");
+    printf("<style>body{font-family:Arial;margin:40px;}"
+           "h1{color:#2a7;}.result{background:#f5f5f5;padding:20px;"
+           "border-radius:10px;font-size:1.5em;text-align:center;}"
+           "a{color:#667eea;}</style>\n");
+    printf("</head><body>\n");
+    printf("<h1>🔧 CGI 动态计算器 (实验4)</h1>\n");
+
+    /* 从 stdin 读取 POST 数据 */
+    char post_data[1024] = "";
+    if (method && strcmp(method, "POST") == 0) {
+        char *len_str = getenv("CONTENT_LENGTH");
+        if (len_str) {
+            int len = atoi(len_str);
+            if (len > 0 && len < (int)sizeof(post_data) - 1) {
+                fread(post_data, 1, len, stdin);
+                post_data[len] = '\0';
+            }
+        }
+        query = post_data;
+    }
+
+    /* 解析参数 a 和 b */
+    int a = 0, b = 0;
+    if (query) {
+        char *pa = strstr(query, "a=");
+        char *pb = strstr(query, "b=");
+        if (pa) a = atoi(pa + 2);
+        if (pb) b = atoi(pb + 2);
+    }
+
+    printf("<div class=\"result\">\n");
+    printf("<p>%d + %d = <strong>%d</strong></p>\n", a, b, a + b);
+    printf("<p>Method: %s | PID: %d</p>\n",
+           method ? method : "UNKNOWN", getpid());
+    printf("</div>\n");
+
+    printf("<p><a href=\"/\">← 返回首页</a></p>\n");
+    printf("<hr><em>Experiment4 CGI v1.0</em>\n");
+    printf("</body></html>\n");
+
+    return 0;
+}

server-exp4/common.c

@@ -0,0 +1,170 @@
+/* $begin common.c */
+#include "common.h"
+
+/*********************************************************************
+ * The Rio package - robust I/O functions
+ **********************************************************************/
+
+ssize_t rio_readn(int fd, void *usrbuf, size_t n)
+{
+    size_t nleft = n;
+    ssize_t nread;
+    char *bufp = usrbuf;
+
+    while (nleft > 0) {
+        if ((nread = read(fd, bufp, nleft)) < 0) {
+            if (errno == EINTR)
+                nread = 0;
+            else
+                return -1;
+        }
+        else if (nread == 0)
+            break;
+        nleft -= nread;
+        bufp += nread;
+    }
+    return (n - nleft);
+}
+
+ssize_t rio_writen(int fd, void *usrbuf, size_t n)
+{
+    size_t nleft = n;
+    ssize_t nwritten;
+    char *bufp = usrbuf;
+
+    while (nleft > 0) {
+        if ((nwritten = write(fd, bufp, nleft)) <= 0) {
+            if (errno == EINTR)
+                nwritten = 0;
+            else
+                return -1;
+        }
+        nleft -= nwritten;
+        bufp += nwritten;
+    }
+    return n;
+}
+
+static ssize_t rio_read(rio_t *rp, char *usrbuf, size_t n)
+{
+    int cnt;
+    while (rp->rio_cnt <= 0) {
+        rp->rio_cnt = read(rp->rio_fd, rp->rio_buf,
+                   sizeof(rp->rio_buf));
+        if (rp->rio_cnt < 0) {
+            if (errno != EINTR)
+                return -1;
+        }
+        else if (rp->rio_cnt == 0)
+            return 0;
+        else
+            rp->rio_bufptr = rp->rio_buf;
+    }
+    cnt = n;
+    if (rp->rio_cnt < n)
+        cnt = rp->rio_cnt;
+    memcpy(usrbuf, rp->rio_bufptr, cnt);
+    rp->rio_bufptr += cnt;
+    rp->rio_cnt -= cnt;
+    return cnt;
+}
+
+void rio_readinitb(rio_t *rp, int fd)
+{
+    rp->rio_fd = fd;
+    rp->rio_cnt = 0;
+    rp->rio_bufptr = rp->rio_buf;
+}
+
+ssize_t rio_readnb(rio_t *rp, void *usrbuf, size_t n)
+{
+    size_t nleft = n;
+    ssize_t nread;
+    char *bufp = usrbuf;
+
+    while (nleft > 0) {
+        if ((nread = rio_read(rp, bufp, nleft)) < 0) {
+            if (errno == EINTR)
+                nread = 0;
+            else
+                return -1;
+        }
+        else if (nread == 0)
+            break;
+        nleft -= nread;
+        bufp += nread;
+    }
+    return (n - nleft);
+}
+
+ssize_t rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen)
+{
+    int n, rc;
+    char c, *bufp = usrbuf;
+
+    for (n = 1; n < maxlen; n++) {
+        if ((rc = rio_read(rp, &c, 1)) == 1) {
+            *bufp++ = c;
+            if (c == '\n')
+                break;
+        } else if (rc == 0) {
+            if (n == 1)
+                return 0;
+            else
+                break;
+        } else
+            return -1;
+    }
+    *bufp = 0;
+    return n;
+}
+
+/********************************
+ * Client/server helper functions
+ ********************************/
+
+int open_client_sock(char *hostname, int port)
+{
+    int client_sock;
+    struct hostent *hp;
+    struct sockaddr_in serveraddr;
+
+    if ((client_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+        return -1;
+
+    if ((hp = gethostbyname(hostname)) == NULL)
+        return -2;
+    bzero((char *) &serveraddr, sizeof(serveraddr));
+    serveraddr.sin_family = AF_INET;
+    bcopy((char *)hp->h_addr_list[0],
+          (char *)&serveraddr.sin_addr.s_addr, hp->h_length);
+    serveraddr.sin_port = htons(port);
+
+    if (connect(client_sock, (SA *) &serveraddr, sizeof(serveraddr)) < 0)
+        return -1;
+    return client_sock;
+}
+
+int open_listen_sock(int port)
+{
+    int listen_sock, optval=1;
+    struct sockaddr_in serveraddr;
+
+    if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+        return -1;
+
+    if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
+               (const void *)&optval , sizeof(int)) < 0)
+        return -1;
+
+    bzero((char *) &serveraddr, sizeof(serveraddr));
+    serveraddr.sin_family = AF_INET;
+    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
+    serveraddr.sin_port = htons((unsigned short)port);
+    if (bind(listen_sock, (SA *)&serveraddr, sizeof(serveraddr)) < 0)
+        return -1;
+
+    if (listen(listen_sock, LISTENQ) < 0)
+        return -1;
+    return listen_sock;
+}

server-exp4/common.h

@@ -0,0 +1,66 @@
+/* $begin common.h */
+#ifndef __COMMON_H__
+#define __COMMON_H__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <ctype.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <math.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <limits.h>
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+
+/* Default file permissions */
+#define DEF_MODE   S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH
+#define DEF_UMASK  S_IWGRP|S_IWOTH
+
+/* Simplifies calls to bind(), connect(), and accept() */
+typedef struct sockaddr SA;
+
+/* Persistent state for the robust I/O (Rio) package */
+#define RIO_BUFSIZE 8192
+typedef struct {
+    int rio_fd;
+    int rio_cnt;
+    char *rio_bufptr;
+    char rio_buf[RIO_BUFSIZE];
+} rio_t;
+
+/* External variables */
+extern int h_errno;
+extern char **environ;
+
+/* Misc constants */
+#define	MAXLINE	 8192
+#define MAXBUF   8192
+#define LISTENQ  1024
+
+/* Rio (Robust I/O) package */
+ssize_t rio_readn(int fd, void *usrbuf, size_t n);
+ssize_t rio_writen(int fd, void *usrbuf, size_t n);
+void rio_readinitb(rio_t *rp, int fd);
+ssize_t	rio_readnb(rio_t *rp, void *usrbuf, size_t n);
+ssize_t	rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen);
+
+/* Client/server helper functions */
+int open_client_sock(char *hostname, int portno);
+int open_listen_sock(int portno);
+
+#endif /* __COMMON_H__ */

server-exp4/index.html

@@ -0,0 +1,191 @@
+<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+<meta charset="UTF-8">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<title>实验4 高性能Web服务器 - 测试页面</title>
+<style>
+    * { margin: 0; padding: 0; box-sizing: border-box; }
+    body {
+        font-family: 'Segoe UI', Arial, sans-serif;
+        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+        min-height: 100vh;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+    }
+    .container {
+        background: white;
+        border-radius: 20px;
+        padding: 40px;
+        max-width: 800px;
+        width: 90%;
+        box-shadow: 0 20px 60px rgba(0,0,0,0.3);
+    }
+    h1 {
+        color: #333;
+        text-align: center;
+        margin-bottom: 10px;
+        font-size: 2em;
+    }
+    h2 {
+        color: #555;
+        text-align: center;
+        margin-bottom: 30px;
+        font-weight: normal;
+    }
+    .features {
+        display: grid;
+        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+        gap: 15px;
+        margin-bottom: 30px;
+    }
+    .feature-card {
+        background: #f8f9fa;
+        border-radius: 10px;
+        padding: 20px;
+        text-align: center;
+        border: 2px solid #e9ecef;
+        transition: transform 0.2s, border-color 0.2s;
+    }
+    .feature-card:hover {
+        transform: translateY(-3px);
+        border-color: #667eea;
+    }
+    .feature-icon { font-size: 2em; margin-bottom: 10px; }
+    .feature-title { font-weight: bold; color: #333; margin-bottom: 5px; }
+    .feature-desc { font-size: 0.9em; color: #666; }
+    .test-section {
+        background: #f8f9fa;
+        border-radius: 10px;
+        padding: 20px;
+        margin-bottom: 20px;
+    }
+    .test-section h3 {
+        color: #333;
+        margin-bottom: 15px;
+        border-bottom: 2px solid #667eea;
+        padding-bottom: 8px;
+    }
+    form {
+        display: flex;
+        flex-direction: column;
+        gap: 10px;
+    }
+    input[type="text"], input[type="email"], textarea {
+        padding: 10px;
+        border: 2px solid #ddd;
+        border-radius: 8px;
+        font-size: 1em;
+        transition: border-color 0.2s;
+    }
+    input:focus, textarea:focus {
+        border-color: #667eea;
+        outline: none;
+    }
+    button, .btn {
+        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+        color: white;
+        padding: 12px 24px;
+        border: none;
+        border-radius: 8px;
+        font-size: 1em;
+        cursor: pointer;
+        transition: transform 0.2s, box-shadow 0.2s;
+        text-decoration: none;
+        display: inline-block;
+        text-align: center;
+    }
+    button:hover, .btn:hover {
+        transform: translateY(-2px);
+        box-shadow: 0 5px 15px rgba(102,126,234,0.4);
+    }
+    .link-list { list-style: none; padding: 0; }
+    .link-list li { margin: 8px 0; }
+    .link-list a {
+        color: #667eea;
+        text-decoration: none;
+        font-weight: 500;
+    }
+    .link-list a:hover { text-decoration: underline; }
+    .server-info {
+        text-align: center;
+        color: #999;
+        font-size: 0.85em;
+        margin-top: 20px;
+    }
+    pre { background: white; padding: 15px; border-radius: 8px; overflow-x: auto; }
+</style>
+</head>
+<body>
+<div class="container">
+    <h1>🚀 实验4 高性能Web服务器</h1>
+    <h2>epoll + 线程池 + LRU缓存 + GET/POST</h2>
+
+    <div class="features">
+        <div class="feature-card">
+            <div class="feature-icon">⚡</div>
+            <div class="feature-title">epoll I/O复用</div>
+            <div class="feature-desc">基于epoll的边缘触发模式，高效处理海量并发连接</div>
+        </div>
+        <div class="feature-card">
+            <div class="feature-icon">🧵</div>
+            <div class="feature-title">线程池</div>
+            <div class="feature-desc">预创建工作线程，避免频繁创建销毁开销</div>
+        </div>
+        <div class="feature-card">
+            <div class="feature-icon">💾</div>
+            <div class="feature-title">LRU缓存</div>
+            <div class="feature-desc">哈希表+双向链表，O(1)查找与淘汰</div>
+        </div>
+        <div class="feature-card">
+            <div class="feature-icon">📡</div>
+            <div class="feature-title">GET/POST</div>
+            <div class="feature-desc">完整支持HTTP GET和POST方法</div>
+        </div>
+    </div>
+
+    <div class="test-section">
+        <h3>📋 功能测试</h3>
+        <ul class="link-list">
+            <li><a href="/test.html">📄 静态页面测试 (GET)</a></li>
+            <li><a href="/example.jpg">🖼️ 图片访问测试 (JPEG)</a></li>
+            <li><a href="/nonexistent.html">❌ 404错误页面测试</a></li>
+            <li><a href="/cgi-bin/add?a=10&b=20">🔧 CGI动态内容测试</a></li>
+        </ul>
+    </div>
+
+    <div class="test-section">
+        <h3>📝 POST 方法测试</h3>
+        <form action="/submit" method="POST">
+            <label for="name">姓名:</label>
+            <input type="text" id="name" name="name" placeholder="输入您的姓名" required>
+            <label for="email">邮箱:</label>
+            <input type="email" id="email" name="email" placeholder="输入您的邮箱" required>
+            <label for="message">留言:</label>
+            <textarea id="message" name="message" rows="3" placeholder="输入您的留言..."></textarea>
+            <button type="submit">✉️ 提交 POST 请求</button>
+        </form>
+    </div>
+
+    <div class="test-section">
+        <h3>📊 缓存测试</h3>
+        <p style="color:#666;margin-bottom:10px;">
+            多次访问同一资源观察 X-Cache 响应头: 首次 MISS，后续 HIT
+        </p>
+        <pre># 测试缓存命中
+curl -I http://localhost:8088/index.html
+# 第一次: X-Cache: MISS
+# 第二次: X-Cache: HIT (从缓存返回)
+
+# 压力测试
+ab -n 10000 -c 100 http://localhost:8088/index.html
+wrk -t4 -c100 -d30s http://localhost:8088/index.html</pre>
+    </div>
+
+    <div class="server-info">
+        <p>Powered by Experiment4-WebServer v40.0 | epoll + Thread Pool + LRU Cache</p>
+    </div>
+</div>
+</body>
+</html>

server-exp4/test.html

@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+<meta charset="UTF-8">
+<title>静态页面测试 - 实验4</title>
+<style>
+    body { font-family: Arial, sans-serif; margin: 40px; background: #f0f4f8; color: #333; }
+    h1 { color: #2a7; }
+    .box { background: white; padding: 20px; border-radius: 10px; margin: 15px 0;
+           box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
+    table { width: 100%; border-collapse: collapse; margin: 15px 0; }
+    th, td { border: 1px solid #ddd; padding: 10px; text-align: left; }
+    th { background: #667eea; color: white; }
+    a { color: #667eea; }
+</style>
+</head>
+<body>
+    <h1>📄 静态页面测试</h1>
+    <p>本页面用于验证Web服务器的静态资源服务能力（包括缓存功能）。</p>
+
+    <div class="box">
+        <h2>服务器特性对比</h2>
+        <table>
+            <tr><th>版本</th><th>I/O模型</th><th>并发模型</th><th>缓存</th><th>方法</th></tr>
+            <tr><td>实验1</td><td>阻塞I/O</td><td>单进程</td><td>❌</td><td>GET</td></tr>
+            <tr><td>实验2</td><td>阻塞I/O</td><td>多线程/预线程</td><td>❌</td><td>GET</td></tr>
+            <tr><td>实验3</td><td>阻塞I/O</td><td>线程池/流水线</td><td>❌</td><td>GET</td></tr>
+            <tr><td style="color:#2a7;font-weight:bold;">实验4</td>
+                <td style="color:#2a7;">epoll</td>
+                <td style="color:#2a7;">线程池</td>
+                <td style="color:#2a7;">✅ LRU</td>
+                <td style="color:#2a7;">GET+POST</td></tr>
+        </table>
+    </div>
+
+    <div class="box">
+        <h2>实验4 新增功能</h2>
+        <ul>
+            <li><strong>epoll I/O多路复用:</strong> 主线程使用epoll监控所有连接，边缘触发模式</li>
+            <li><strong>LRU缓存:</strong> 哈希表 + 双向链表，O(1)查找和淘汰</li>
+            <li><strong>POST方法:</strong> 支持表单提交和CGI转发</li>
+            <li><strong>缓存命中指示:</strong> 响应头 X-Cache: HIT/MISS</li>
+        </ul>
+    </div>
+
+    <p><a href="/">← 返回首页</a></p>
+</body>
+</html>

server-exp4/thpool.c

@@ -0,0 +1,478 @@
+/* ********************************
+ * Author:       Johan Hanssen Seferidis
+ * License:	     MIT
+ * Description:  Library providing a threading pool where you can add
+ *               work. For usage, check the thpool.h file or README.md
+ *
+ */
+/** @file thpool.h */ /*
+                       *
+                       ********************************/
+
+#if defined(__APPLE__)
+#include <AvailabilityMacros.h>
+#else
+#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#endif
+#ifndef _XOPEN_SOURCE
+#define _XOPEN_SOURCE 500
+#endif
+#endif
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#if defined(__linux__)
+#include <sys/prctl.h>
+#endif
+#if defined(__FreeBSD__) || defined(__OpenBSD__)
+#include <pthread_np.h>
+#endif
+
+#include "thpool.h"
+
+#ifdef THPOOL_DEBUG
+#define THPOOL_DEBUG 1
+#else
+#define THPOOL_DEBUG 0
+#endif
+
+#if !defined(DISABLE_PRINT) || defined(THPOOL_DEBUG)
+#define err(str) fprintf(stderr, str)
+#else
+#define err(str)
+#endif
+
+#ifndef THPOOL_THREAD_NAME
+#define THPOOL_THREAD_NAME thpool
+#endif
+
+#define STRINGIFY(x) #x
+#define TOSTRING(x) STRINGIFY(x)
+
+static volatile int threads_keepalive;
+static volatile int threads_on_hold;
+
+/* Thread-local worker ID，供外部模块统计每个线程的请求处理数 */
+__thread int thpool_worker_id = -1;
+
+/* ========================== STRUCTURES ============================ */
+
+
+/* ========================== PROTOTYPES ============================ */
+
+static int thread_init(thpool_* thpool_p, struct thread** thread_p, int id);
+static void* thread_do(struct thread* thread_p);
+static void thread_hold(int sig_id);
+static void thread_destroy(struct thread* thread_p);
+
+static int jobqueue_init(jobqueue* jobqueue_p);
+static void jobqueue_clear(jobqueue* jobqueue_p);
+static void jobqueue_push(jobqueue* jobqueue_p, struct job* newjob_p);
+static struct job* jobqueue_pull(jobqueue* jobqueue_p);
+static void jobqueue_destroy(jobqueue* jobqueue_p);
+
+static void bsem_init(struct bsem* bsem_p, int value);
+static void bsem_reset(struct bsem* bsem_p);
+static void bsem_post(struct bsem* bsem_p);
+static void bsem_post_all(struct bsem* bsem_p);
+static void bsem_wait(struct bsem* bsem_p);
+
+/* ========================== THREADPOOL ============================ */
+
+/* Initialise thread pool */
+struct thpool_* thpool_init(int num_threads) {
+    threads_on_hold = 0;
+    threads_keepalive = 1;
+
+    if (num_threads < 0) {
+        num_threads = 0;
+    }
+
+    /* Make new thread pool */
+    thpool_* thpool_p;
+    thpool_p = (struct thpool_*)malloc(sizeof(struct thpool_));
+    if (thpool_p == NULL) {
+        err("thpool_init(): Could not allocate memory for thread pool\n");
+        return NULL;
+    }
+    thpool_p->num_threads_alive = 0;
+    thpool_p->num_threads_working = 0;
+
+    /* Initialise the job queue */
+    if (jobqueue_init(&thpool_p->jobqueue) == -1) {
+        err("thpool_init(): Could not allocate memory for job queue\n");
+        free(thpool_p);
+        return NULL;
+    }
+
+    /* Make threads in pool */
+    thpool_p->threads = (struct thread**)malloc(num_threads * sizeof(struct thread*));
+    if (thpool_p->threads == NULL) {
+        err("thpool_init(): Could not allocate memory for threads\n");
+        jobqueue_destroy(&thpool_p->jobqueue);
+        free(thpool_p);
+        return NULL;
+    }
+
+    pthread_mutex_init(&(thpool_p->thcount_lock), NULL);
+    pthread_cond_init(&thpool_p->threads_all_idle, NULL);
+
+    /* Thread init */
+    int n;
+    for (n = 0; n < num_threads; n++) {
+        thread_init(thpool_p, &thpool_p->threads[n], n);
+#if THPOOL_DEBUG
+        printf("THPOOL_DEBUG: Created thread %d in pool \n", n);
+#endif
+    }
+
+    /* Wait for threads to initialize */
+    while (thpool_p->num_threads_alive != num_threads) {
+    }
+
+    return thpool_p;
+}
+
+/* Add work to the thread pool */
+int thpool_add_work(thpool_* thpool_p, void (*function_p)(void*), void* arg_p) {
+    job* newjob;
+
+    newjob = (struct job*)malloc(sizeof(struct job));
+    if (newjob == NULL) {
+        err("thpool_add_work(): Could not allocate memory for new job\n");
+        return -1;
+    }
+
+    /* add function and argument */
+    newjob->function = function_p;
+    newjob->arg = arg_p;
+
+    /* add job to queue */
+    jobqueue_push(&thpool_p->jobqueue, newjob);
+
+    return 0;
+}
+
+/* Wait until all jobs have finished */
+void thpool_wait(thpool_* thpool_p) {
+    pthread_mutex_lock(&thpool_p->thcount_lock);
+    while (thpool_p->jobqueue.len || thpool_p->num_threads_working) {
+        pthread_cond_wait(&thpool_p->threads_all_idle, &thpool_p->thcount_lock);
+    }
+    pthread_mutex_unlock(&thpool_p->thcount_lock);
+}
+
+/* Destroy the threadpool */
+void thpool_destroy(thpool_* thpool_p) {
+    /* No need to destroy if it's NULL */
+    if (thpool_p == NULL) return;
+
+    volatile int threads_total = thpool_p->num_threads_alive;
+
+    /* End each thread 's infinite loop */
+    threads_keepalive = 0;
+
+    /* Give one second to kill idle threads */
+    double TIMEOUT = 1.0;
+    time_t start, end;
+    double tpassed = 0.0;
+    time(&start);
+    while (tpassed < TIMEOUT && thpool_p->num_threads_alive) {
+        bsem_post_all(thpool_p->jobqueue.has_jobs);
+        time(&end);
+        tpassed = difftime(end, start);
+    }
+
+    /* Poll remaining threads */
+    while (thpool_p->num_threads_alive) {
+        bsem_post_all(thpool_p->jobqueue.has_jobs);
+        sleep(1);
+    }
+
+    /* Job queue cleanup */
+    jobqueue_destroy(&thpool_p->jobqueue);
+    /* Deallocs */
+    int n;
+    for (n = 0; n < threads_total; n++) {
+        thread_destroy(thpool_p->threads[n]);
+    }
+    free(thpool_p->threads);
+    free(thpool_p);
+}
+
+/* Pause all threads in threadpool */
+void thpool_pause(thpool_* thpool_p) {
+    int n;
+    for (n = 0; n < thpool_p->num_threads_alive; n++) {
+        pthread_kill(thpool_p->threads[n]->pthread, SIGUSR1);
+    }
+}
+
+/* Resume all threads in threadpool */
+void thpool_resume(thpool_* thpool_p) {
+    // resuming a single threadpool hasn't been
+    // implemented yet, meanwhile this suppresses
+    // the warnings
+    (void)thpool_p;
+
+    threads_on_hold = 0;
+}
+
+int thpool_num_threads_working(thpool_* thpool_p) { return thpool_p->num_threads_working; }
+
+/* ============================ THREAD ============================== */
+
+/* Initialize a thread in the thread pool
+ *
+ * @param thread        address to the pointer of the thread to be created
+ * @param id            id to be given to the thread
+ * @return 0 on success, -1 otherwise.
+ */
+static int thread_init(thpool_* thpool_p, struct thread** thread_p, int id) {
+    *thread_p = (struct thread*)malloc(sizeof(struct thread));
+    if (*thread_p == NULL) {
+        err("thread_init(): Could not allocate memory for thread\n");
+        return -1;
+    }
+
+    (*thread_p)->thpool_p = thpool_p;
+    (*thread_p)->id = id;
+
+    pthread_create(&(*thread_p)->pthread, NULL, (void* (*)(void*))thread_do, (*thread_p));
+    pthread_detach((*thread_p)->pthread);
+    return 0;
+}
+
+/* Sets the calling thread on hold */
+static void thread_hold(int sig_id) {
+    (void)sig_id;
+    threads_on_hold = 1;
+    while (threads_on_hold) {
+        sleep(1);
+    }
+}
+
+/* What each thread is doing
+ *
+ * In principle this is an endless loop. The only time this loop gets interrupted is once
+ * thpool_destroy() is invoked or the program exits.
+ *
+ * @param  thread        thread that will run this function
+ * @return nothing
+ */
+static void* thread_do(struct thread* thread_p) {
+    /* Set thread name for profiling and debugging */
+    char thread_name[16] = {0};
+
+    snprintf(thread_name, 16, TOSTRING(THPOOL_THREAD_NAME) "-%d", thread_p->id);
+
+#if defined(__linux__)
+    /* Use prctl instead to prevent using _GNU_SOURCE flag and implicit declaration */
+    prctl(PR_SET_NAME, thread_name);
+#elif defined(__APPLE__) && defined(__MACH__)
+    pthread_setname_np(thread_name);
+#elif defined(__FreeBSD__) || defined(__OpenBSD__)
+    pthread_set_name_np(thread_p->pthread, thread_name);
+#else
+    err("thread_do(): pthread_setname_np is not supported on this system");
+#endif
+
+    /* Assure all threads have been created before starting serving */
+    thpool_* thpool_p = thread_p->thpool_p;
+
+    /* Register signal handler */
+    struct sigaction act;
+    sigemptyset(&act.sa_mask);
+    act.sa_flags = SA_ONSTACK;
+    act.sa_handler = thread_hold;
+    if (sigaction(SIGUSR1, &act, NULL) == -1) {
+        err("thread_do(): cannot handle SIGUSR1");
+    }
+
+    /* Mark thread as alive (initialized) */
+    pthread_mutex_lock(&thpool_p->thcount_lock);
+    thpool_p->num_threads_alive += 1;
+    pthread_mutex_unlock(&thpool_p->thcount_lock);
+
+    while (threads_keepalive) {
+        bsem_wait(thpool_p->jobqueue.has_jobs);
+
+        if (threads_keepalive) {
+            pthread_mutex_lock(&thpool_p->thcount_lock);
+            thpool_p->num_threads_working++;
+            pthread_mutex_unlock(&thpool_p->thcount_lock);
+
+            /* Read job from queue and execute it */
+            void (*func_buff)(void*);
+            void* arg_buff;
+            job* job_p = jobqueue_pull(&thpool_p->jobqueue);
+            if (job_p) {
+             #ifdef DEBUG
+                printf("线程%d开始处理\n",thread_p->id);
+             #endif
+                func_buff = job_p->function;
+                arg_buff = job_p->arg;
+                thpool_worker_id = thread_p->id;   /* 设置 thread-local ID */
+                func_buff(arg_buff);
+                
+             #ifdef DEBUG 
+                printf("线程%d处理完成\n",thread_p->id);
+             #endif                
+                free(job_p);
+            }
+
+            pthread_mutex_lock(&thpool_p->thcount_lock);
+            thpool_p->num_threads_working--;
+            if (!thpool_p->num_threads_working) {
+                pthread_cond_signal(&thpool_p->threads_all_idle);
+            }
+            pthread_mutex_unlock(&thpool_p->thcount_lock);
+        }
+    }
+    pthread_mutex_lock(&thpool_p->thcount_lock);
+    thpool_p->num_threads_alive--;
+    pthread_mutex_unlock(&thpool_p->thcount_lock);
+
+    return NULL;
+}
+
+/* Frees a thread  */
+static void thread_destroy(thread* thread_p) { free(thread_p); }
+
+/* ============================ JOB QUEUE =========================== */
+
+/* Initialize queue */
+static int jobqueue_init(jobqueue* jobqueue_p) {
+    jobqueue_p->len = 0;
+    jobqueue_p->front = NULL;
+    jobqueue_p->rear = NULL;
+
+    jobqueue_p->has_jobs = (struct bsem*)malloc(sizeof(struct bsem));
+    if (jobqueue_p->has_jobs == NULL) {
+        return -1;
+    }
+
+    pthread_mutex_init(&(jobqueue_p->rwmutex), NULL);
+    bsem_init(jobqueue_p->has_jobs, 0);
+
+    return 0;
+}
+
+/* Clear the queue */
+static void jobqueue_clear(jobqueue* jobqueue_p) {
+    while (jobqueue_p->len) {
+        free(jobqueue_pull(jobqueue_p));
+    }
+
+    jobqueue_p->front = NULL;
+    jobqueue_p->rear = NULL;
+    bsem_reset(jobqueue_p->has_jobs);
+    jobqueue_p->len = 0;
+}
+
+/* Add (allocated) job to queue
+ */
+static void jobqueue_push(jobqueue* jobqueue_p, struct job* newjob) {
+    pthread_mutex_lock(&jobqueue_p->rwmutex);
+    newjob->prev = NULL;
+
+    switch (jobqueue_p->len) {
+        case 0: /* if no jobs in queue */
+            jobqueue_p->front = newjob;
+            jobqueue_p->rear = newjob;
+            break;
+
+        default: /* if jobs in queue */
+            jobqueue_p->rear->prev = newjob;
+            jobqueue_p->rear = newjob;
+    }
+    jobqueue_p->len++;
+
+    bsem_post(jobqueue_p->has_jobs);
+    pthread_mutex_unlock(&jobqueue_p->rwmutex);
+}
+
+/* Get first job from queue(removes it from queue)
+ * Notice: Caller MUST hold a mutex
+ */
+static struct job* jobqueue_pull(jobqueue* jobqueue_p) {
+    pthread_mutex_lock(&jobqueue_p->rwmutex);
+    job* job_p = jobqueue_p->front;
+
+    switch (jobqueue_p->len) {
+        case 0: /* if no jobs in queue */
+            break;
+
+        case 1: /* if one job in queue */
+            jobqueue_p->front = NULL;
+            jobqueue_p->rear = NULL;
+            jobqueue_p->len = 0;
+            break;
+
+        default: /* if >1 jobs in queue */
+            jobqueue_p->front = job_p->prev;
+            jobqueue_p->len--;
+            /* more than one job in queue -> post it */
+            bsem_post(jobqueue_p->has_jobs);
+    }
+
+    pthread_mutex_unlock(&jobqueue_p->rwmutex);
+    return job_p;
+}
+
+/* Free all queue resources back to the system */
+static void jobqueue_destroy(jobqueue* jobqueue_p) {
+    jobqueue_clear(jobqueue_p);
+    free(jobqueue_p->has_jobs);
+}
+
+/* ======================== SYNCHRONISATION ========================= */
+
+/* Init semaphore to 1 or 0 */
+static void bsem_init(bsem* bsem_p, int value) {
+    if (value < 0 || value > 1) {
+        err("bsem_init(): Binary semaphore can take only values 1 or 0");
+        exit(1);
+    }
+    pthread_mutex_init(&(bsem_p->mutex), NULL);
+    pthread_cond_init(&(bsem_p->cond), NULL);
+    bsem_p->v = value;
+}
+
+/* Reset semaphore to 0 */
+static void bsem_reset(bsem* bsem_p) {
+    pthread_mutex_destroy(&(bsem_p->mutex));
+    pthread_cond_destroy(&(bsem_p->cond));
+    bsem_init(bsem_p, 0);
+}
+
+/* Post to at least one thread */
+static void bsem_post(bsem* bsem_p) {
+    pthread_mutex_lock(&bsem_p->mutex);
+    bsem_p->v = 1;
+    pthread_cond_signal(&bsem_p->cond);
+    pthread_mutex_unlock(&bsem_p->mutex);
+}
+
+/* Post to all threads */
+static void bsem_post_all(bsem* bsem_p) {
+    pthread_mutex_lock(&bsem_p->mutex);
+    bsem_p->v = 1;
+    pthread_cond_broadcast(&bsem_p->cond);
+    pthread_mutex_unlock(&bsem_p->mutex);
+}
+
+/* Wait on semaphore until semaphore has value 0 */
+static void bsem_wait(bsem* bsem_p) {
+    pthread_mutex_lock(&bsem_p->mutex);
+    while (bsem_p->v != 1) {
+        pthread_cond_wait(&bsem_p->cond, &bsem_p->mutex);
+    }
+    bsem_p->v = 0;
+    pthread_mutex_unlock(&bsem_p->mutex);
+}

server-exp4/thpool.h

@@ -0,0 +1,222 @@
+/**********************************
+ * @author      Johan Hanssen Seferidis
+ * License:     MIT
+ *
+ **********************************/
+
+#ifndef _THPOOL_
+#define _THPOOL_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* =================================== API ======================================= */
+
+/* ========================== STRUCTURES ============================ */
+
+/* Binary semaphore */
+typedef struct bsem {
+    pthread_mutex_t mutex;
+    pthread_cond_t cond;
+    int v;
+} bsem;
+
+/* Job */
+typedef struct job {
+    struct job* prev;            /* pointer to previous job   */
+    void (*function)(void* arg); /* function pointer          */
+    void* arg;                   /* function's argument       */
+} job;
+
+/* Job queue */
+typedef struct jobqueue {
+    pthread_mutex_t rwmutex; /* used for queue r/w access */
+    job* front;              /* pointer to front of queue */
+    job* rear;               /* pointer to rear  of queue */
+    bsem* has_jobs;          /* flag as binary semaphore  */
+    int len;                 /* number of jobs in queue   */
+} jobqueue;
+
+/* Thread */
+typedef struct thread {
+    int id;                   /* friendly id               */
+    pthread_t pthread;        /* pointer to actual thread  */
+    struct thpool_* thpool_p; /* access to thpool          */
+} thread;
+
+/* Threadpool */
+typedef struct thpool_ {
+    thread** threads;                 /* pointer to threads        */
+    volatile int num_threads_alive;   /* threads currently alive   */
+    volatile int num_threads_working; /* threads currently working */
+    pthread_mutex_t thcount_lock;     /* used for thread count etc */
+    pthread_cond_t threads_all_idle;  /* signal to thpool_wait     */
+    jobqueue jobqueue;                /* job queue                 */
+} thpool_;
+
+typedef struct thpool_* threadpool;
+
+/**
+ * @brief  Initialize threadpool
+ *
+ * Initializes a threadpool. This function will not return until all
+ * threads have initialized successfully.
+ *
+ * @example
+ *
+ *    ..
+ *    threadpool thpool;                     //First we declare a threadpool
+ *    thpool = thpool_init(4);               //then we initialize it to 4 threads
+ *    ..
+ *
+ * @param  num_threads   number of threads to be created in the threadpool
+ * @return threadpool    created threadpool on success,
+ *                       NULL on error
+ */
+threadpool thpool_init(int num_threads);
+
+/**
+ * @brief Add work to the job queue
+ *
+ * Takes an action and its argument and adds it to the threadpool's job queue.
+ * If you want to add to work a function with more than one arguments then
+ * a way to implement this is by passing a pointer to a structure.
+ *
+ * NOTICE: You have to cast both the function and argument to not get warnings.
+ *
+ * @example
+ *
+ *    void print_num(int num){
+ *       printf("%d\n", num);
+ *    }
+ *
+ *    int main() {
+ *       ..
+ *       int a = 10;
+ *       thpool_add_work(thpool, (void*)print_num, (void*)a);
+ *       ..
+ *    }
+ *
+ * @param  threadpool    threadpool to which the work will be added
+ * @param  function_p    pointer to function to add as work
+ * @param  arg_p         pointer to an argument
+ * @return 0 on success, -1 otherwise.
+ */
+int thpool_add_work(threadpool, void (*function_p)(void*), void* arg_p);
+
+/**
+ * @brief Wait for all queued jobs to finish
+ *
+ * Will wait for all jobs - both queued and currently running to finish.
+ * Once the queue is empty and all work has completed, the calling thread
+ * (probably the main program) will continue.
+ *
+ * Smart polling is used in wait. The polling is initially 0 - meaning that
+ * there is virtually no polling at all. If after 1 seconds the threads
+ * haven't finished, the polling interval starts growing exponentially
+ * until it reaches max_secs seconds. Then it jumps down to a maximum polling
+ * interval assuming that heavy processing is being used in the threadpool.
+ *
+ * @example
+ *
+ *    ..
+ *    threadpool thpool = thpool_init(4);
+ *    ..
+ *    // Add a bunch of work
+ *    ..
+ *    thpool_wait(thpool);
+ *    puts("All added work has finished");
+ *    ..
+ *
+ * @param threadpool     the threadpool to wait for
+ * @return nothing
+ */
+void thpool_wait(threadpool);
+
+/**
+ * @brief Pauses all threads immediately
+ *
+ * The threads will be paused no matter if they are idle or working.
+ * The threads return to their previous states once thpool_resume
+ * is called.
+ *
+ * While the thread is being paused, new work can be added.
+ *
+ * @example
+ *
+ *    threadpool thpool = thpool_init(4);
+ *    thpool_pause(thpool);
+ *    ..
+ *    // Add a bunch of work
+ *    ..
+ *    thpool_resume(thpool); // Let the threads start their magic
+ *
+ * @param threadpool    the threadpool where the threads should be paused
+ * @return nothing
+ */
+void thpool_pause(threadpool);
+
+/**
+ * @brief Unpauses all threads if they are paused
+ *
+ * @example
+ *    ..
+ *    thpool_pause(thpool);
+ *    sleep(10);              // Delay execution 10 seconds
+ *    thpool_resume(thpool);
+ *    ..
+ *
+ * @param threadpool     the threadpool where the threads should be unpaused
+ * @return nothing
+ */
+void thpool_resume(threadpool);
+
+/**
+ * @brief Destroy the threadpool
+ *
+ * This will wait for the currently active threads to finish and then 'kill'
+ * the whole threadpool to free up memory.
+ *
+ * @example
+ * int main() {
+ *    threadpool thpool1 = thpool_init(2);
+ *    threadpool thpool2 = thpool_init(2);
+ *    ..
+ *    thpool_destroy(thpool1);
+ *    ..
+ *    return 0;
+ * }
+ *
+ * @param threadpool     the threadpool to destroy
+ * @return nothing
+ */
+void thpool_destroy(threadpool);
+
+/**
+ * @brief Show currently working threads
+ *
+ * Working threads are the threads that are performing work (not idle).
+ *
+ * @example
+ * int main() {
+ *    threadpool thpool1 = thpool_init(2);
+ *    threadpool thpool2 = thpool_init(2);
+ *    ..
+ *    printf("Working threads: %d\n", thpool_num_threads_working(thpool1));
+ *    ..
+ *    return 0;
+ * }
+ *
+ * @param threadpool     the threadpool of interest
+ * @return integer       number of threads working
+ */
+int thpool_num_threads_working(threadpool);
+threadpool* initThreadPool(int);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

server-exp4/urls.txt

@@ -0,0 +1,16 @@
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=1&b=2
+http://localhost:8088/cgi-bin/add?a=10&b=20
+http://localhost:8088/cgi-bin/add?a=100&b=200
+http://localhost:8088/cgi-bin/add?a=5&b=15
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=7&b=8
+http://localhost:8088/cgi-bin/add?a=99&b=1
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=50&b=50
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=33&b=67
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=6&b=14
+http://localhost:8088/index.html
+http://localhost:8088/cgi-bin/add?a=42&b=58