httpd.cpp

//
// Created by vergil on 17-4-26.
//

#include <sys/ioctl.h>
#include <linux/sockios.h>

#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "httpd.h"
#include "ZlSocket.h"


void accept_request(ZlSocket * client)
{
    char buf[1024];
    int numchars;
    char method[255];
    char url[255];
    char path[512];
    size_t i, j;
    struct stat st;
    int cgi = 0;      /* becomes true if server decides this is a CGI
                    * program */
    char *query_string = NULL;

    numchars = get_line(client, buf, sizeof(buf));
#ifdef DEBUG
    printf("in accept_request n is %d and buf is %s\n",sizeof(buf),buf);
#endif
    i = 0; j = 0;
    while (!ISspace(buf[j]) && (i < sizeof(method) - 1))
    {
        method[i] = buf[j];
        i++; j++;
    }
    method[i] = '\0';

    if (strcasecmp(method, "GET") && strcasecmp(method, "POST"))
    {
        unimplemented(client);
        return;
    }

    if (strcasecmp(method, "POST") == 0)
        cgi = 1;

    i = 0;
    while (ISspace(buf[j]) && (j < sizeof(buf)))
        j++;
    while (!ISspace(buf[j]) && (i < sizeof(url) - 1) && (j < sizeof(buf)))
    {
        url[i] = buf[j];
        i++; j++;
    }
    url[i] = '\0';

    if (strcasecmp(method, "GET") == 0)
    {
        query_string = url;
        while ((*query_string != '?') && (*query_string != '\0'))
            query_string++;
        if (*query_string == '?')
        {
            cgi = 1;
            *query_string = '\0';
            query_string++;
        }
    }

    sprintf(path, "htdocs%s", url);
    if (path[strlen(path) - 1] == '/')
        strcat(path, "index.html");
    if (stat(path, &st) == -1) {
        while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
            numchars = get_line(client, buf, sizeof(buf));
        not_found(client);
    }
    else
    {
        if ((st.st_mode & S_IFMT) == S_IFDIR)
            strcat(path, "/index.html");
        if ((st.st_mode & S_IXUSR) ||
            (st.st_mode & S_IXGRP) ||
            (st.st_mode & S_IXOTH)    )
            cgi = 1;
        if (!cgi)
            serve_file(client, path);
        else
            execute_cgi(client, path, method, query_string);
    }

    client->close();
}

/**********************************************************************/
/* Inform the client that a request it has made has a problem.
 * Parameters: client socket */
/**********************************************************************/
void bad_request(ZlSocket *client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 400 BAD REQUEST\r\n");
    client->send(buf, sizeof(buf), 0);
    sprintf(buf, "Content-type: text/html\r\n");
    client->send(buf, sizeof(buf), 0);
    sprintf(buf, "\r\n");
    client->send(buf, sizeof(buf), 0);
    sprintf(buf, "<P>Your browser sent a bad request, ");
    client->send(buf, sizeof(buf), 0);
    sprintf(buf, "such as a POST without a Content-Length.\r\n");
    client->send(buf, sizeof(buf), 0);
}

/**********************************************************************/
/* Put the entire contents of a file out on a socket.  This function
 * is named after the UNIX "cat" command, because it might have been
 * easier just to do something like pipe, fork, and exec("cat").
 * Parameters: the client socket descriptor
 *             FILE pointer for the file to cat */
/**********************************************************************/
void cat(ZlSocket *client, FILE *resource)
{
    char buf[1024];

    fgets(buf, sizeof(buf), resource);
    while (!feof(resource))
    {
        client->send(buf, strlen(buf), 0);
        fgets(buf, sizeof(buf), resource);
    }
}

/**********************************************************************/
/* Inform the client that a CGI script could not be executed.
 * Parameter: the client socket descriptor. */
/**********************************************************************/
void cannot_execute(ZlSocket* client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 500 Internal Server Error\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "Content-type: text/html\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "<P>Error prohibited CGI execution.\r\n");
    client->send(buf, strlen(buf), 0);
}

/**********************************************************************/
/* Print out an error message with perror() (for system errors; based
 * on value of errno, which indicates system call errors) and exit the
 * program indicating an error. */
/**********************************************************************/
void error_die(const char *sc)
{
    perror(sc);
    exit(1);
}

/**********************************************************************/
/* Execute a CGI script.  Will need to set environment variables as
 * appropriate.
 * Parameters: client socket descriptor
 *             path to the CGI script */
/**********************************************************************/
void execute_cgi(ZlSocket *client, const char *path,
                 const char *method, const char *query_string)
{
    char buf[1024];
    int cgi_output[2];
    int cgi_input[2];
    pid_t pid;
    int status;
    int i;
    char c;
    int numchars = 1;
    int content_length = -1;

    buf[0] = 'A'; buf[1] = '\0';
    if (strcasecmp(method, "GET") == 0)
        while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
            numchars = get_line(client, buf, sizeof(buf));
    else    /* POST */
    {
        numchars = get_line(client, buf, sizeof(buf));
        while ((numchars > 0) && strcmp("\n", buf))
        {
            buf[15] = '\0';
            if (strcasecmp(buf, "Content-Length:") == 0)
                content_length = atoi(&(buf[16]));
            numchars = get_line(client, buf, sizeof(buf));
        }
        if (content_length == -1) {
            bad_request(client);
            return;
        }
    }

    sprintf(buf, "HTTP/1.0 200 OK\r\n");
    client->send(buf, strlen(buf), 0);

    if (pipe(cgi_output) < 0) {
        cannot_execute(client);
        return;
    }
    if (pipe(cgi_input) < 0) {
        cannot_execute(client);
        return;
    }

    if ( (pid = fork()) < 0 ) {
        cannot_execute(client);
        return;
    }
    if (pid == 0)  /* child: CGI script */
    {
        char meth_env[255];
        char query_env[255];
        char length_env[255];

        dup2(cgi_output[1], 1);
        dup2(cgi_input[0], 0);
        close(cgi_output[0]);
        close(cgi_input[1]);
        sprintf(meth_env, "REQUEST_METHOD=%s", method);
        putenv(meth_env);
        if (strcasecmp(method, "GET") == 0) {
            sprintf(query_env, "QUERY_STRING=%s", query_string);
            putenv(query_env);
        }
        else {   /* POST */
            sprintf(length_env, "CONTENT_LENGTH=%d", content_length);
            putenv(length_env);
        }
        execl(path, path, NULL);
        exit(0);
    } else {    /* parent */
        close(cgi_output[1]);
        close(cgi_input[0]);
        if (strcasecmp(method, "POST") == 0)
            for (i = 0; i < content_length; i++) {
                client->recv(&c, 1, 0);
                write(cgi_input[1], &c, 1);
            }
        while (read(cgi_output[0], &c, 1) > 0)
            client->send(&c, 1, 0);

        close(cgi_output[0]);
        close(cgi_input[1]);
        waitpid(pid, &status, 0);
    }
}

/**********************************************************************/
/* Get a line from a socket, whether the line ends in a newline,
 * carriage return, or a CRLF combination.  Terminates the string read
 * with a null character.  If no newline indicator is found before the
 * end of the buffer, the string is terminated with a null.  If any of
 * the above three line terminators is read, the last character of the
 * string will be a linefeed and the string will be terminated with a
 * null character.
 * Parameters: the socket descriptor
 *             the buffer to save the data in
 *             the size of the buffer
 * Returns: the number of bytes stored (excluding null) */
/**********************************************************************/
int get_line(ZlSocket* sock, char *buf, int size)
{
    int i = 0;
    char c = '\0';
    int n;

    while ((i < size - 1) && (c != '\n'))
    {
        n = sock->recv(&c, 1, 0);
        /* DEBUG printf("%02X\n", c); */
        if (n > 0)
        {
            if (c == '\r')
            {
                n = sock->recv(&c, 1, MSG_PEEK);
                /* DEBUG printf("%02X\n", c); */
                if ((n > 0) && (c == '\n'))
                    sock->recv(&c, 1, 0);
                else
                    c = '\n';
            }
            buf[i] = c;
            i++;
        }
        else
            c = '\n';
    }
    buf[i] = '\0';

    return(i);
}

/**********************************************************************/
/* Return the informational HTTP headers about a file. */
/* Parameters: the socket to print the headers on
 *             the name of the file */
/**********************************************************************/
void headers(ZlSocket* client, const char *filename)
{
    char buf[1024];
    (void)filename;  /* could use filename to determine file type */

    strcpy(buf, "HTTP/1.0 200 OK\r\n");
    client -> send(buf, strlen(buf), 0);
    strcpy(buf, SERVER_STRING);
    client -> send(buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    client -> send(buf, strlen(buf), 0);
    strcpy(buf, "\r\n");
    client -> send(buf, strlen(buf), 0);
}

/**********************************************************************/
/* Give a client a 404 not found status message. */
/**********************************************************************/
void not_found(int client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 404 NOT FOUND\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, SERVER_STRING);
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "<HTML><TITLE>Not Found</TITLE>\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "<BODY><P>The server could not fulfill\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "your request because the resource specified\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "is unavailable or nonexistent.\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "</BODY></HTML>\r\n");
    send(client, buf, strlen(buf), 0);
}

bool IsSocketClosed(int clientSocket){
    char buff[32];
    ssize_t n = recv(clientSocket, buff, sizeof(buff), MSG_PEEK);
    if(n==0)
        return true;
    if(n>0)
        return false;
    int sockErr = errno;
    if(sockErr==EAGAIN || sockErr==EWOULDBLOCK)   //receive successfully, client works normally
        return false;
    if( sockErr==EINTR) //resouce temporarilly unavailable
        return false;
    fprintf(stderr,"client socket closed\n");
    return true;
}
int make_socket_non_blocking (int sfd){
    int flags, s;

    //得到文件状态标志
    flags = fcntl (sfd, F_GETFL, 0);
    if (flags == -1){
        perror ("fcntl");
        return -1;
    }
    //设置文件状态标志
    flags |= O_NONBLOCK;
    s = fcntl (sfd, F_SETFL, flags);
    if (s == -1){
        perror ("fcntl");
        return -1;
    }
    return 0;
}
void closeSocket(int client){
    uint32_t cycles1=0,cycles2=0;
    int oldpending=0;
    bool client_closed=false;
    int pending=0;
    ioctl(client, SIOCOUTQ, &pending);
    oldpending=pending;
    if(pending==0){
       // printf("close socket immediately\n");
        goto closing;
    }
    if(make_socket_non_blocking(client)==-1){
       // printf("failed to make socket non-blocking\n");
        close(client);
        return;
    }
    while(!client_closed && pending>0 && cycles1<1000){
        cycles1++;
        cycles2=0;
        while(!client_closed && pending>0 && cycles2<5000){
            usleep(1000);
            ioctl(client, SIOCOUTQ, &pending);
            client_closed=IsSocketClosed(client);
            cycles2++;
        }
        //fprintf(stderr,"cycles1=%u   cycles2=%u\n",cycles1,cycles2);
        if(oldpending==pending)   // the value of pending should be less
            break;
        oldpending=pending;
    }
    closing:
    int fig=close(client);
    while(fig<0){
        if(errno==EINTR)
            fig = close(client);
        else
            break;
    }
   // fprintf(stderr,"cycles1=%u   cycles2=%u for socket %d\n",cycles1,cycles2,client);
}
void not_found(ZlSocket* client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 404 NOT FOUND\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, SERVER_STRING);
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "<HTML><TITLE>Not Found</TITLE>\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "<BODY><P>The server could not fulfill\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "your request because the resource specified\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "is unavailable or nonexistent.\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "</BODY></HTML>\r\n");
    client->send(buf, strlen(buf), 0);
}

/**********************************************************************/
/* Send a regular file to the client.  Use headers, and report
 * errors to client if they occur.
 * Parameters: a pointer to a file structure produced from the socket
 *              file descriptor
 *             the name of the file to serve */
/**********************************************************************/
void serve_file(ZlSocket *client, const char *filename)
{
    FILE *resource = NULL;
    int numchars = 1;
    char buf[1024];

    buf[0] = 'A'; buf[1] = '\0';
    while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
        numchars = get_line(client, buf, sizeof(buf));

    resource = fopen(filename, "r");
    if (resource == NULL)
        not_found(client);
    else
    {
        headers(client, filename);
        cat(client, resource);
    }
    fclose(resource);
}

/**********************************************************************/
/* This function starts the process of listening for web connections
 * on a specified port.  If the port is 0, then dynamically allocate a
 * port and modify the original port variable to reflect the actual
 * port.
 * Parameters: pointer to variable containing the port to connect on
 * Returns: the socket */
/**********************************************************************/
int startup(u_short *port)
{
    int httpd = 0;
    struct sockaddr_in name;

    httpd = socket(PF_INET, SOCK_STREAM, 0);
    if (httpd == -1)
        error_die("socket");
    memset(&name, 0, sizeof(name));
    name.sin_family = AF_INET;
    name.sin_port = htons(*port);
    name.sin_addr.s_addr = htonl(INADDR_ANY);
    if (bind(httpd, (struct sockaddr *)&name, sizeof(name)) < 0)
        error_die("bind");
    if (*port == 0)  /* if dynamically allocating a port */
    {
        socklen_t namelen = sizeof(name);
        if (getsockname(httpd, (struct sockaddr *)&name, &namelen) == -1)
            error_die("getsockname");
        *port = ntohs(name.sin_port);
    }
    if (listen(httpd, 5) < 0)
        error_die("listen");
    return(httpd);
}

/**********************************************************************/
/* Inform the client that the requested web method has not been
 * implemented.
 * Parameter: the client socket */
/**********************************************************************/
void unimplemented(ZlSocket* client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 501 Method Not Implemented\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, SERVER_STRING);
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "<HTML><HEAD><TITLE>Method Not Implemented\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "</TITLE></HEAD>\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "<BODY><P>HTTP request method not supported.\r\n");
    client->send(buf, strlen(buf), 0);
    sprintf(buf, "</BODY></HTML>\r\n");
    client->send(buf, strlen(buf), 0);

}