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serverC
| 
| Odsłony: 86/*
* tiny.c - a minimal HTTP server that serves static and
* dynamic content with the GET method. Neither
* robust, secure, nor modular. Use for instructional
* purposes only.
* Dave O'Hallaron, Carnegie Mellon
*
* usage: tiny <port>
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define BUFSIZE 1024
#define MAXERRS 16
extern char **environ; /* the environment */
/*
* error - wrapper for perror used for bad syscalls
*/
void error(char *msg) {
perror(msg);
exit(1);
}
/*
* cerror - returns an error message to the client
*/
void cerror(FILE *stream, char *cause, char *errno,
char *shortmsg, char *longmsg) {
fprintf(stream, "HTTP/1.1 %s %s\n", errno, shortmsg);
fprintf(stream, "Content-type: text/html\n");
fprintf(stream, "\n");
fprintf(stream, "<html><title>Tiny Error</title>");
fprintf(stream, "<body bgcolor=""ffffff"">\n");
fprintf(stream, "%s: %s\n", errno, shortmsg);
fprintf(stream, "<p>%s: %s\n", longmsg, cause);
fprintf(stream, "<hr><em>The Tiny Web server</em>\n");
}
int main(int argc, char **argv) {
/* variables for connection management */
int parentfd; /* parent socket */
int childfd; /* child socket */
int portno; /* port to listen on */
int clientlen; /* byte size of client's address */
struct hostent *hostp; /* client host info */
char *hostaddrp; /* dotted decimal host addr string */
int optval; /* flag value for setsockopt */
struct sockaddr_in serveraddr; /* server's addr */
struct sockaddr_in clientaddr; /* client addr */
/* variables for connection I/O */
FILE *stream; /* stream version of childfd */
char buf[BUFSIZE]; /* message buffer */
char method[BUFSIZE]; /* request method */
char uri[BUFSIZE]; /* request uri */
char version[BUFSIZE]; /* request method */
char filename[BUFSIZE];/* path derived from uri */
char filetype[BUFSIZE];/* path derived from uri */
char cgiargs[BUFSIZE]; /* cgi argument list */
char *p; /* temporary pointer */
int is_static; /* static request? */
struct stat sbuf; /* file status */
int fd; /* static content filedes */
int pid; /* process id from fork */
int wait_status; /* status from wait */
/* check command line args */
if (argc != 2) {
fprintf(stderr, "usage: %s <port>\n", argv[0]);
exit(1);
}
portno = atoi(argv[1]);
/* open socket descriptor */
parentfd = socket(AF_INET, SOCK_STREAM, 0);
if (parentfd < 0)
error("ERROR opening socket");
/* allows us to restart server immediately */
optval = 1;
setsockopt(parentfd, SOL_SOCKET, SO_REUSEADDR,
(const void *)&optval , sizeof(int));
/* bind port to socket */
bzero((char *) &serveraddr, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
serveraddr.sin_port = htons((unsigned short)portno);
if (bind(parentfd, (struct sockaddr *) &serveraddr,
sizeof(serveraddr)) < 0)
error("ERROR on binding");
/* get us ready to accept connection requests */
if (listen(parentfd, 5) < 0) /* allow 5 requests to queue up */
error("ERROR on listen");
/*
* main loop: wait for a connection request, parse HTTP,
* serve requested content, close connection.
*/
clientlen = sizeof(clientaddr);
while (1) {
/* wait for a connection request */
childfd = accept(parentfd, (struct sockaddr *) &clientaddr, &clientlen);
if (childfd < 0)
error("ERROR on accept");
/* determine who sent the message */
hostp = gethostbyaddr((const char *)&clientaddr.sin_addr.s_addr,
sizeof(clientaddr.sin_addr.s_addr), AF_INET);
if (hostp == NULL)
error("ERROR on gethostbyaddr");
hostaddrp = inet_ntoa(clientaddr.sin_addr);
if (hostaddrp == NULL)
error("ERROR on inet_ntoa\n");
/* open the child socket descriptor as a stream */
if ((stream = fdopen(childfd, "r+")) == NULL)
error("ERROR on fdopen");
/* get the HTTP request line */
fgets(buf, BUFSIZE, stream);
printf("%s", buf);
sscanf(buf, "%s %s %s\n", method, uri, version);
/* tiny only supports the GET method */
if (strcasecmp(method, "GET")) {
cerror(stream, method, "501", "Not Implemented",
"Tiny does not implement this method");
fclose(stream);
close(childfd);
continue;
}
/* read (and ignore) the HTTP headers */
fgets(buf, BUFSIZE, stream);
printf("%s", buf);
while(strcmp(buf, "\r\n")) {
fgets(buf, BUFSIZE, stream);
printf("%s", buf);
}
/* parse the uri [crufty] */
if (!strstr(uri, "cgi-bin")) { /* static content */
is_static = 1;
strcpy(cgiargs, "");
strcpy(filename, ".");
strcat(filename, uri);
if (uri[strlen(uri)-1] == '/')
strcat(filename, "index.html");
}
else { /* dynamic content */
is_static = 0;
p = index(uri, '?');
if (p) {
strcpy(cgiargs, p+1);
*p = '\0';
}
else {
strcpy(cgiargs, "");
}
strcpy(filename, ".");
strcat(filename, uri);
}
/* make sure the file exists */
if (stat(filename, &sbuf) < 0) {
cerror(stream, filename, "404", "Not found",
"Tiny couldn't find this file");
fclose(stream);
close(childfd);
continue;
}
/* serve static content */
if (is_static) {
if (strstr(filename, ".html"))
strcpy(filetype, "text/html");
else if (strstr(filename, ".gif"))
strcpy(filetype, "image/gif");
else if (strstr(filename, ".jpg"))
strcpy(filetype, "image/jpg");
else
strcpy(filetype, "text/plain");
/* print response header */
fprintf(stream, "HTTP/1.1 200 OK\n");
fprintf(stream, "Server: Tiny Web Server\n");
fprintf(stream, "Content-length: %d\n", (int)sbuf.st_size);
fprintf(stream, "Content-type: %s\n", filetype);
fprintf(stream, "\r\n");
fflush(stream);
/* Use mmap to return arbitrary-sized response body */
fd = open(filename, O_RDONLY);
p = mmap(0, sbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
fwrite(p, 1, sbuf.st_size, stream);
munmap(p, sbuf.st_size);
}
/* serve dynamic content */
else {
/* make sure file is a regular executable file */
if (!(S_IFREG & sbuf.st_mode) || !(S_IXUSR & sbuf.st_mode)) {
cerror(stream, filename, "403", "Forbidden",
"You are not allow to access this item");
fclose(stream);
close(childfd);
continue;
}
/* a real server would set other CGI environ vars as well*/
setenv("QUERY_STRING", cgiargs, 1);
/* print first part of response header */
sprintf(buf, "HTTP/1.1 200 OK\n");
write(childfd, buf, strlen(buf));
sprintf(buf, "Server: Tiny Web Server\n");
write(childfd, buf, strlen(buf));
/* create and run the child CGI process so that all child
output to stdout and stderr goes back to the client via the
childfd socket descriptor */
pid = fork();
if (pid < 0) {
perror("ERROR in fork");
exit(1);
}
else if (pid > 0) { /* parent process */
wait(&wait_status);
}
else { /* child process*/
close(0); /* close stdin */
dup2(childfd, 1); /* map socket to stdout */
dup2(childfd, 2); /* map socket to stderr */
if (execve(filename, NULL, environ) < 0) {
perror("ERROR in execve");
}
}
}
/* clean up */
fclose(stream);
close(childfd);
}
}