#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define PRECHILD 5
#define MAXCHILD 50
#define BUFSIZE 4096
#define PIDPATH "pid"
#define head503 "HTTP/1.1 503 Service unavailable\r\n"
#define head404 "HTTP/1.1 404 Not Found\r\n"
#define head200 "HTTP/1.1 200 0K\n\rContent—Type: text/html\n\rContent—Length: "
int len503, len404, len200;
int fd1[2], fd2[2];
typedef struct {
pid_t pid;
char status; // 'n' means new request; 'f' means finish the request
} REPORT;
void answer(int listenfd)
{
int connfd;
char buf[BUFSIZE];
int count;
int pid = getpid();
struct sockaddr_in cliaddr;
int size = sizeof(cliaddr);
char comm;
REPORT rep;
rep.pid = pid;
while (1) {
connfd = accept(listenfd, (struct sockaddr *)&cliaddr,(socklen_t *)&size ); //子进程accept请求
rep.status = 'n';
if (write(fd1[1], &rep, sizeof(rep)) < 0) { //通知父进程已经accept了请求
perror("write pipe new failed");
exit(-1);
}
count = read(connfd, buf, BUFSIZE);
char req[10];
char filepath[256];
sscanf(buf, "%s%s", req, filepath + 1);
filepath[0] = '.';
if (strcmp("GET", req) != 0) {//503
write(connfd, head503, len503);
//goto err_out;
close(connfd);
exit(-1);
}
char content[BUFSIZE];
struct stat stbuf;
if (lstat(filepath, &stbuf) != 0) {
int err = errno;
if (err == ENOENT) {//404
write(connfd, head404, len404);
}
close(connfd);
exit(-1);
}
count = write(connfd, head200, len200);
u_int filesize = stbuf.st_size;
sprintf(content, "%u\n\r\n\r", filesize);
count = write(connfd, content, strlen(content));
FILE *fp = fopen(filepath, "r");
if (fp == NULL) {
printf("open file %s failed\n", filepath);
close(connfd);
exit(-1);
}
while((count = fread(content, 1, sizeof(content), fp)) > 0) {
//printf("%s", content);
if (write(connfd, content, count) != count) {
printf("write failed\n");
}
}
fclose(fp);
close(connfd);
rep.status = 'f';
if (write(fd1[1], &rep, sizeof(rep)) < 0) {//告诉父进程自己处理完了请求
perror("write pipe finish failed");
exit(-1);
}
if (read(fd2[0], &comm, 1) < 1) {//等待来自父进程的命令
perror("read pipe failed");
exit(-1);
}
//printf("[%d] reve %c from pa\n", pid, comm);
if (comm == 'e') { //收到exit命令
printf("[%d] exit\n", pid);
exit(-1);
}
else if (comm == 'c') { //收到继续accept的命令
printf("[%d] continue\n", pid);
}
else {
printf("[%d] comm : %c illeagle\n", pid, comm);
}
}
}
void usage()
{
printf("Usage: http-serv port\n");
}
int write_pid()
{
int fd;
if ((fd = open(PIDPATH, O_WRONLY | O_TRUNC | O_CREAT, S_IWUSR)) < 0){
perror("open pidfile faild");
return -1;
}
struct flock lock;
lock.l_type = F_WRLCK;
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 0;
if (fcntl(fd, F_SETLK, &lock) == -1) {
int err = errno;
perror("fcntl faild");
if (err == EAGAIN) {
printf("Another http-serv process is running now!\n");
}
return -1;
}
return 0;
}
void daemon_init()
{
//clear file creation mask;
umask(0);
//become a session leader
if (fork() != 0)
exit(-1);
if (setsid() < 0)
exit(-1);
//make sure can be never get the TTY control
if (fork() != 0)
exit(-1);
//may chdir here
int i;
for (i = 0; i < 1024; i++)
close(i);
/*
* Attach file descriptors 0, 1, and 2 to /dev/null.
*/
int fd0, fd1, fd2;
fd0 = open("/dev/null", O_RDWR);
fd1 = dup(0);
fd2 = dup(0);
if (fd0 != 0 || fd1 != 1 || fd2 != 2) {
printf("init failed\n");
exit(-1);
}
}
int
main(int argc, char **argv)
{
int listenfd;
struct sockaddr_in servaddr;
pid_t pid;
if (argc != 2) {
usage();
return -1;
}
signal(SIGCHLD, SIG_IGN);
len200 = strlen(head200);
len404 = strlen(head404);
len503 = strlen(head503);
daemon_init(); //转为后台程序，如需打印调试，把这行注释掉
if (write_pid() < 0) //避免同时有多个该程序在运行
return -1;
if (pipe(fd1) < 0) {
perror("pipe failed");
exit(-1);
}
if (s_pipe(fd2) < 0) {
perror("pipe failed");
exit(-1);
}
int port = atoi(argv[1]);
//initialize servaddr and listenfd...
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(port);
listenfd = socket(AF_INET, SOCK_STREAM, 0);
bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
listen(listenfd, 1000);
int i;
for (i = 0; i < PRECHILD ; i++) { //父进程预fork 子进程
if ((pid = fork()) < 0) {
perror("fork faild");
exit(3);
}
else if (pid == 0) {
answer(listenfd);
}
else {
printf("have create child %d\n", pid);
}
}
char e = 'e';
char c = 'c';
int req_num = 0;
int child_num = PRECHILD;
REPORT rep;
while (1) {
//printf("req_num = %d, child_num = %d\n", req_num, child_num);
if (read(fd1[0], &rep, sizeof(rep)) < sizeof(rep)) {//等待子进程发来消息
perror("parent read pipe failed");
exit(-1);
}
//printf("parent: receive from %d\n", pid);
if (rep.status == 'n') {//子进程刚accept了新的请求
req_num ++;
printf("parent: %d have receive new request\n", rep.pid);
if (req_num >= child_num && child_num <= MAXCHILD) { //请求数过多，创建更多子进程
if ((pid = fork()) < 0) {
perror("fork faild");
exit(3);
}
else if (pid == 0) {
answer(listenfd);
}
else {
printf("have create child %d\n", pid);
child_num ++;
}
}
}
else if (rep.status == 'f') {//子进程刚处理完了一个请求
req_num --;
//printf("parent: %d have finish a request\n", rep.pid);
if (child_num > (req_num + 1) && child_num > PRECHILD) {//子进程数过多，删除多余的子进程
if (write(fd2[1], &e, sizeof(e)) < sizeof(e)) {
perror("pa write pipe failed");
exit(-2);
}
//printf("tell child exit\n");
child_num --;
}
else {
if (write(fd2[1], &c, sizeof(c)) < sizeof(c)) {//让子进程继续等待accept
perror("pa write pipe failed");
exit(-2);
}
//printf("tell child continue\n");
}
}
}
return 0;
}
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