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httpd.cpp
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httpd.cpp
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//
// 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);
}