Linux C简单的web服务器

一、基础类型重命名

二、包裹函数（wrap.h/wrap.c 主要是网络通讯和多线程的包裹函数）

三、服务端程序（web_server.h/web_server.c）—— 使用EPOLL高并发机制

四、HTTP解析（http.h/http.c写了一个基本的框架，很容易添加需要解析的文件类型）

五、项目目录组织（以项目的角度建立工程）

六、编译执行

HTTP基本协议

HTTP基本协议参照上面链接。我这里只介绍软件的设计过程和源码。

一、基础类型重命名

#ifndef _TYPE_H_
#define _TYPE_H_/* exact-width signed integer types */
typedef   signed           char int8_t;
typedef   signed short     int int16_t;
typedef   signed           int int32_t;/* exact-width unsigned integer types */
typedef unsigned           char uint8_t;
typedef unsigned short     int uint16_t;
typedef unsigned           int uint32_t;
//typedef unsigned           int size_t;#ifndef NULL
#ifdef __cplusplus              // EC++
#define NULL   0
#else
#define NULL   ((void *) 0)
#endif
#endif#ifndef boolean
typedef uint8_t boolean;
#endif#ifndef FALSE
#define FALSE 0
#endif#ifndef TRUE
#define TRUE  1
#endif#endif /* _TYPE_H_ */

二、包裹函数（wrap.h/wrap.c 主要是网络通讯和多线程的包裹函数）

#ifndef WRAP_H
#define WRAP_H#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/epoll.h>
#include <pthread.h>//===================================Socket/File Wrapper Function==========================================
int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr);
void Bind(int fd, const struct sockaddr* sa, socklen_t salen);
void Connect(int fd, const struct sockaddr* sa, socklen_t salen);
void Listen(int fd, int backlog);
int Socket(int family, int type, int protocol);
void Setsockopt(int fd, int level, int optname, void *optval, socklen_t optlen);
int Ioctl(int d, int request, ...);
ssize_t Read(int fd, void *ptr, size_t nbytes);
ssize_t Write(int fd, const void *ptr, size_t nbytes);
ssize_t Readn(int fd, void *vptr, size_t n);
ssize_t Writen(int fd, const void*vptr, size_t n);
ssize_t Readline(int fd, void *vptr, size_t maxlen);
int Open(const char *pathname, int flags, mode_t mode);
void Close(int fd);//========================================Epoll Wrapper function============================================
int Epollcreate(int size);
int Epollctl(int epfd, int op, int fd, struct epoll_event *event);
int Epollwait(int epfd, struct epoll_event * events, int maxevents, int timeout);//======================================pthread Wrapper function============================================
void Pthread_create(pthread_t *tid, const pthread_attr_t *attr, void * (*func)(void *), void *arg);
void Pthread_detach(pthread_t tid);
void Pthread_join(pthread_t tid, void **status);
void Pthread_mutex_lock(pthread_mutex_t *mptr);
void Pthread_mutex_unlock(pthread_mutex_t *mptr);
void Pthread_cond_signal(pthread_cond_t *cptr);
void Pthread_cond_wait(pthread_cond_t *cptr, pthread_mutex_t *mptr);#endif

#include "wrap.h"static void perr_exit(const char *s)
{perror(s);exit(1);
}int Accept(int fd, struct sockaddr *sa, socklen_t* salenptr)
{int newfd;
again:if((newfd = accept(fd, sa, salenptr)) < 0){if((errno == ECONNABORTED) || (errno == EINTR)){goto again;}else{perr_exit("accept error");}}return newfd;
}void Bind(int fd, const struct sockaddr* sa, socklen_t salen)
{if(bind(fd, sa, salen) < 0){perr_exit("bind error");}
}void Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{if(connect(fd, sa, salen) < 0){perr_exit("connect error");}
}void Listen(int fd, int backlog)
{if(listen(fd, backlog) < 0){perr_exit("listen error");}
}int Socket(int family, int type, int protocol)
{int socketfd;if((socketfd = socket(family, type, protocol)) < 0){perr_exit("socket error");}return socketfd;
}void Setsockopt(int fd, int level, int optname, void *optval, socklen_t optlen)
{if(-1 == setsockopt(fd, level, optname, optval, optlen)){perr_exit("setsockopt error");}
}ssize_t Read(int fd, void *ptr, size_t nbytes)
{ssize_t n;
again:if((n = read(fd, ptr, nbytes)) == -1){if(errno == EINTR){goto again;}else{return -1;}}return n;
}ssize_t Write(int fd, const void *ptr, size_t nbytes)
{ssize_t n;
again:if((n = write(fd, ptr, nbytes)) == -1){if(errno == EINTR){goto again;}else{return -1;}}return n;
}ssize_t Readn(int fd, void *vptr, size_t n)
{size_t nleft;ssize_t nread;char *ptr;ptr = vptr;nleft = n;while(nleft > 0){if((nread = read(fd, ptr, nleft)) < 0){if(errno == EINTR){nread = 0;}else{return -1;}}else if(nread == 0){break;}nleft -= nread;ptr += nread;}return (n - nleft);
}ssize_t Writen(int fd, const void *vptr, size_t n)
{size_t nleft;ssize_t nwritten;const char* ptr;ptr = vptr;nleft = n;while(nleft > 0){if((nwritten = write(fd, ptr, nleft)) <= 0){if(nwritten < 0 && errno == EINTR){nwritten = 0;}else{return -1;}}nleft -= nwritten;ptr += nwritten;}return n;
}static ssize_t my_read(int fd, char *ptr)
{static int read_cnt;static char *read_ptr;static char read_buf[100];if(read_cnt <= 0){
again:if((read_cnt = read(fd, read_buf, sizeof(read_buf))) < 0){if(errno == EINTR){goto again;}else{return -1;}}else if(read_cnt == 0){return 0;}read_ptr = read_buf;}read_cnt--;*ptr = *read_ptr++;return 1;
}ssize_t Readline(int fd, void *vptr, size_t maxlen)
{ssize_t n, rc;char c, *ptr;ptr = vptr;for(n = 1; n < maxlen; n++){if((rc = my_read(fd, &c)) == 1){*ptr++ = c;if(c == '\n'){break;}}else if(rc == 0){*ptr = 0;return n - 1;}else{return (n - 1);}}*ptr = 0;return n;
}int Open(const char *pathname, int flags, mode_t mode)
{int fd = open(pathname, flags, mode);if( -1 == fd ){perr_exit("open file error...");}return fd;
}void Close(int fd)
{if(close(fd) == -1){perr_exit("close error...");}
}int Epollcreate(int size)
{int sockfd;if((sockfd = epoll_create(size)) == -1){perr_exit("epoll create error...");}return sockfd;
}int Epollctl(int epfd, int op, int fd, struct epoll_event *event)
{int status;if((status = epoll_ctl(epfd, op, fd, event)) == -1){perr_exit("epoll ctl error...");}return status;
}int Epollwait(int epfd, struct epoll_event * events, int maxevents, int timeout)
{int ret;if((ret = epoll_wait(epfd, events, maxevents, timeout)) == -1){perr_exit("epoll wait error...");}return ret;
}void Pthread_create(pthread_t *tid, const pthread_attr_t *attr,void * (*func)(void *), void *arg)
{int n = pthread_create(tid, attr, func, arg);if ( n == 0){return;}errno = n;perr_exit("pthread_create error");
}void Pthread_detach(pthread_t tid)
{int n = pthread_detach(tid);if ( n == 0){return;}errno = n;perr_exit("pthread_detach error");
}void Pthread_join(pthread_t tid, void **status)
{int n = pthread_join(tid, status);if ( n == 0 ){return;}errno = n;perr_exit("pthread_join error");
}void Pthread_mutex_lock(pthread_mutex_t *mptr)
{int n = pthread_mutex_lock(mptr);if ( n == 0 ){return;}errno = n;perr_exit("pthread_mutex_lock error...");
}void Pthread_mutex_unlock(pthread_mutex_t *mptr)
{int n = pthread_mutex_unlock(mptr);if ( n == 0 ){return;}errno = n;perr_exit("pthread_mutex_unlock error...");
}void Pthread_cond_signal(pthread_cond_t *cptr)
{int n = pthread_cond_signal(cptr);if ( n == 0 ){return;}errno = n;perr_exit("pthread_cond_signal error...");
}void Pthread_cond_wait(pthread_cond_t *cptr, pthread_mutex_t *mptr)
{int n = pthread_cond_wait(cptr, mptr);if ( n == 0 ){return;}errno = n;perr_exit("pthread_cond_wait error...");
}

三、服务端程序（web_server.h/web_server.c）—— 使用EPOLL高并发机制

#ifndef SERVER_H_
#define SERVER_H_#include <pthread.h>
#include <sys/epoll.h>
#include "wrap.h"
#include "klist.h"#define WEB_SERVER_PORT     80
#define WEB_SOCKET_EVENTS   65535typedef struct
{int client_fd;struct sockaddr_in client_addr;struct list_head list;
} web_client_t;typedef struct
{int sockfd;                // server socketint port;                  // server portstruct sockaddr_in addr;   // server addrint epollfd;               // epoll handlestruct epoll_event event_list[WEB_SOCKET_EVENTS]; // epoll event listpthread_t recv_thread;web_client_t client;       // client list -- save all client info
} web_server_t;/* recv and send queue frame */
#define TCP_FRAME_SIZE 1200
typedef struct
{int sockfd;  // client socketuint16_t length;char data[TCP_FRAME_SIZE];
} web_frame_t;void *WebServertInit(void);#endif /* SERVER_H_ */

#include "web_server.h"
#include "http.h"static web_server_t *web_socket_init(void)
{int opt = 1;web_server_t *current;struct epoll_event event;current = (web_server_t *)malloc(sizeof(web_server_t));current->port = WEB_SERVER_PORT;current->sockfd = Socket(AF_INET, SOCK_STREAM, 0);// SOL_SOCKET: port can same, ip notSetsockopt(current->sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));current->addr.sin_family = AF_INET;current->addr.sin_port = htons(current->port);current->addr.sin_addr.s_addr = INADDR_ANY;Bind(current->sockfd, (struct sockaddr *)&current->addr, sizeof(current->addr));Listen(current->sockfd, 10);current->epollfd = Epollcreate(WEB_SOCKET_EVENTS);event.events = EPOLLIN | EPOLLET;event.data.fd = current->sockfd;// epoll_ctl set addEpollctl(current->epollfd, EPOLL_CTL_ADD, current->sockfd, &event);INIT_LIST_HEAD(&current->client.list);return current;
}static void web_socket_accept(web_server_t *arg)
{web_server_t *current = arg;struct sockaddr_in addr;int len = sizeof(struct sockaddr_in);int new_fd = Accept(current->sockfd, (struct sockaddr *)&addr, (socklen_t *)&len);printf("new connection client_fd ( %d ) %s: %d\n", new_fd, inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));/* register epoll */struct epoll_event event;event.data.fd = new_fd;event.events = EPOLLIN | EPOLLET;Epollctl(current->epollfd, EPOLL_CTL_ADD, new_fd, &event);/* add client node */web_client_t *node = (web_client_t *)malloc(sizeof(web_client_t));node->client_fd = new_fd;memcpy(&node->client_addr, &addr, sizeof(struct sockaddr_in));list_add(&node->list, &current->client.list);
}static void web_socket_recv(web_server_t *arg, int sockfd)
{web_server_t *current = arg;int length = 0;web_frame_t frame = {0};web_client_t *point = NULL;struct list_head *pos, *cur = NULL;length = read(sockfd, frame.data, TCP_FRAME_SIZE);if(0 == length){list_for_each_safe(pos, cur, &current->client.list){/* delete client node, close connect socket */point = list_entry(pos, web_client_t, list);if(point->client_fd == sockfd){printf("client[%d] close\n", sockfd);list_del(pos);free(point);Close(sockfd);}}}else if(length > 0){frame.sockfd = sockfd;frame.length = length;printf("***************************************\r\n");printf("%s\r\n", frame.data);printf("***************************************\r\n");HTTPSend(sockfd, frame.data, frame.length);#if 0list_for_each_safe(pos, cur, &current->client.list){/* delete client node, close connect socket */point = list_entry(pos, web_client_t, list);if(point->client_fd == sockfd){printf("client[%d] close\n", sockfd);list_del(pos);free(point);Close(sockfd);return;}}
#endif}else{exit(-1);}}static void *server_recv_thread(void *arg)
{web_server_t *current = (web_server_t *)arg;while(1){int timeout = 300, i;int ret = Epollwait(current->epollfd, current->event_list, WEB_SOCKET_EVENTS, timeout);if(ret == 0){// timeoutcontinue;}for(i = 0; i < ret; ++i){if((current->event_list[i].events & EPOLLERR) ||(current->event_list[i].events & EPOLLHUP) ||!(current->event_list[i].events & EPOLLIN)){printf("epoll error\n");Close(current->event_list[i].data.fd);exit(-1);}if(current->event_list[i].data.fd == current->sockfd){web_socket_accept(current);}else{web_socket_recv(current, current->event_list[i].data.fd);}}}Close(current->epollfd);Close(current->sockfd);return NULL;
}void * WebServertInit(void)
{web_server_t *current = web_socket_init();Pthread_create(&current->recv_thread, NULL, server_recv_thread, current);return (void *)current;
}

四、HTTP解析（http.h/http.c写了一个基本的框架，很容易添加需要解析的文件类型）

#ifndef _HTTP_H_
#define _HTTP_H_#include "type.h"void HTTPSend(int socketfd, char *content, uint16_t length);#endif /* _HTTP_H_ */

#include "http.h"
#include <stdio.h>
#include <string.h>
#include "wrap.h"static void http_html_cb(int sockfd, const char *filename);
static void http_jpg_cb(int sockfd, const char *filename);
static void http_gif_cb(int sockfd, const char *filename);typedef struct
{char *type;void (* http_cb)(int sockfd, const char *data);
} http_type_t;static http_type_t http_items[] =
{{".html", http_html_cb},{".jpg",  http_jpg_cb},{".jpeg", http_jpg_cb},{".gif" , http_gif_cb},
};static const char *http_ack = "HTTP/1.1 200 OK\r\n""Content-Type: %s\r\n""Server: LiBang's Server V1.0\r\n""Accept-Ranges: bytes\r\n""Content-Length: %d\r\n\r\n";static void http_url(char *http_head, char *file_type, char *filename)
{uint16_t i = 0, j = 0, k = 0;while(http_head[i] != '/'){++i;}while(http_head[i] != '.'){++i;filename[k++] = http_head[i];}while(http_head[i] != ' '){file_type[j++] = http_head[i++];filename[k++] = http_head[i];}filename[k - 1] = '\0'; // delete ' '
}static void http_pakedge_send(int sockfd, const char *filename, char *type)
{FILE *filefd;char http_head[2048] = {0}, buffer[1024000] = {0};uint32_t len;filefd = fopen(filename, "rb");if(filefd == NULL){printf("\r\n error...\r\n");return;}fseek(filefd, 0, SEEK_END);len = ftell(filefd);rewind(filefd);fread(buffer, len, 1, filefd);sprintf(http_head, http_ack, type, len);send(sockfd, http_head, strlen(http_head), 0);send(sockfd, buffer, len, 0);
}static void http_html_cb(int sockfd, const char *filename)
{http_pakedge_send(sockfd, filename, "text/html");
}static void http_jpg_cb(int sockfd, const char *filename)
{http_pakedge_send(sockfd, filename, "image/jpeg");
}static void http_gif_cb(int sockfd, const char *filename)
{http_pakedge_send(sockfd, filename, "image/gif");
}void HTTPSend(int sockfd, char *content, uint16_t length)
{char i, type[36] = {0}, filename[100] = {0};http_url(content, type, filename);printf("URL: %s,  filename: %s\r\n", type, filename);for(i = 0; i < sizeof(http_items) / sizeof(http_items[0]); ++i){if(memcmp(http_items[i].type, type, strlen(http_items[i].type)) == 0){http_items[i].http_cb(sockfd, filename);break;}}
}

要添加的文件类型就在http_items这个结构体数组里面，按照格式添加就OK了。

接下来创建一个html文件（index.html）

<html>
<head><title> Test Page </title></head>
<body><p> Test OK </p><img src = "mypic.jpg">
</body>\
</html>

在这个html里面，网页会显示“Test OK”和一张图片（这个图片自己想办法弄吧，哈哈）。

到这里，项目的架构基本上就完成了，再建一个main.c文件，调用一下接口就完了。

#include <stdio.h>
#include "web_server.h"int main(void)
{WebServertInit();printf("------------test-----------\n");while(1){sleep(1);}return 0;
}

五、项目目录组织（以项目的角度建立工程）

common/

klist.h type.h wrap.c wrap.h Makefile

webserver/

http.h http.c web_server.h web_server.c Makefile

index.html

mypic.jpj

main.c

Makefile

Makefile.build

顶层目录有一个Makefile，各子层目录下都有一个Makefile。

先写顶层目录下的Makefile和Makefile.build

依次是Makefile和Mkefile.build文件，最终会在顶层生成一个可执行文件http（目录可以自行指定）：


CROSS_COMPILE =AS      = $(CROSS_COMPILE)as
LD      = $(CROSS_COMPILE)ld
CC      = $(CROSS_COMPILE)gcc
CPP     = $(CC) -E
AR      = $(CROSS_COMPILE)ar
NM      = $(CROSS_COMPILE)nmSTRIP      = $(CROSS_COMPILE)strip
OBJCOPY     = $(CROSS_COMPILE)objcopy
OBJDUMP     = $(CROSS_COMPILE)objdumpexport AS LD CC CPP AR NM
export STRIP OBJCOPY OBJDUMPCFLAGS := -Wall -O2 -g
CFLAGS += -I $(shell pwd)/common
CFLAGS += -I $(shell pwd)/webserver
CFLAGS += -I $(shell pwd)/LDFLAGS := -lm -lpthreadexport CFLAGS LDFLAGSTOPDIR := $(shell pwd)
export TOPDIRTARGET := httpobj-y += common/
obj-y += webserver/
obj-y += main.oall : make -C ./ -f $(TOPDIR)/Makefile.build$(CC) -o $(TARGET) built-in.o $(LDFLAGS)clean:rm -f $(shell find -name "*.o")rm -f $(shell find -name "*.d")rm -f $(TARGET)

PHONY := __build
__build:obj-y :=
subdir-y :=include Makefile__subdir-y  := $(patsubst %/,%,$(filter %/, $(obj-y)))
subdir-y    += $(__subdir-y)subdir_objs := $(foreach f,$(subdir-y),$(f)/built-in.o)cur_objs := $(filter-out %/, $(obj-y))
dep_files := $(foreach f,$(cur_objs),.$(f).d)
dep_files := $(wildcard $(dep_files))ifneq ($(dep_files),)include $(dep_files)
endifPHONY += $(subdir-y)__build : $(subdir-y) built-in.o$(subdir-y):make -C $@ -f $(TOPDIR)/Makefile.buildbuilt-in.o : $(cur_objs) $(subdir_objs)$(LD) -r -o $@ $^dep_file = .$@.d%.o : %.c$(CC) $(CFLAGS) -Wp,-MD,$(dep_file) -c -o $@ $<.PHONY : $(PHONY)

好了，说完了顶层目录（我就不给各位详细分析Makefile了，我以前也写过Makefile的博客，可以参考），再说说各子层Makefile的编写。上面把模板写好了，各子层就只需要包含它自己的.o文件就好。

common目录下的Makefile：

obj-y += wrap.o

webserver目录下的Makefile：

obj-y += http.o
obj-y += web_server.o

六、编译执行

切换到顶层目录，执行以下make即可生成可执行文件http。

有四个警告，你们去消除吧，哈哈，执行以下看看效果呗，在web网页上面输入 http://自己的IP/index.html，这个index.html是自己编写的。好了看看效果吧，正常解析出了这个html。

我们在log里面也打印出了接收到的消息，我们来看看。

OK，到这里一个最简单的一个web服务器就完成了，服务器采用了epoll机制，打开多个网页不成问题，http解析的部分写的比较简单，但是结构是比较清晰的，根据自己的需要可以添加各种类型的文件，一种类型一个处理函数，框架是不用动的。不过有一点可惜的是，目前大多数都是用https协议了（http+ssl），就是不再是透明传输了，加了一层加密层，让数据更加安全，这个简单的https的实现后面再说。