/* $begin tinymain */
/*
* tiny.c - A simple, iterative HTTP/1.0 Web server that uses the
* GET method to serve static and dynamic content.
*/
#include "csapp.h"
void doit(int fd);
void read_requesthdrs(rio_t *rp);
int parse_uri(char *uri, char *filename, char *cgiargs);
void serve_static(int fd, char *filename, int filesize);
void get_filetype(char *filename, char *filetype);
void serve_dynamic(int fd, char *filename, char *cgiargs);
void clienterror(int fd, char *cause, char *errnum,
char *shortmsg, char *longmsg);
int main(int argc, char **argv)
{
int listenfd, connfd, port, clientlen;
struct sockaddr_in clientaddr;
/* Check command line args */
if (argc != 2) {
fprintf(stderr, "usage: %s <port>\n", argv[0]);
exit(1);
}
port = atoi(argv[1]);
listenfd = Open_listenfd(port);
while (1) {
clientlen = sizeof(clientaddr);
connfd = Accept(listenfd, (SA *)&clientaddr, &clientlen); //line:netp:tiny:accept
doit(connfd); //line:netp:tiny:doit
Close(connfd); //line:netp:tiny:close
}
}
/* $end tinymain */
/*
* doit - handle one HTTP request/response transaction
*/
/* $begin doit */
void doit(int fd)
{
int is_static;
struct stat sbuf;
char buf[MAXLINE], method[MAXLINE], uri[MAXLINE], version[MAXLINE];
char filename[MAXLINE], cgiargs[MAXLINE];
rio_t rio;
/* Read request line and headers */
Rio_readinitb(&rio, fd);
Rio_readlineb(&rio, buf, MAXLINE); //line:netp:doit:readrequest
sscanf(buf, "%s %s %s", method, uri, version); //line:netp:doit:parserequest
if (strcasecmp(method, "GET")) { //line:netp:doit:beginrequesterr
clienterror(fd, method, "501", "Not Implemented",
"Tiny does not implement this method");
return;
} //line:netp:doit:endrequesterr
read_requesthdrs(&rio); //line:netp:doit:readrequesthdrs
/* Parse URI from GET request */
is_static = parse_uri(uri, filename, cgiargs); //line:netp:doit:staticcheck
if (stat(filename, &sbuf) < 0) { //line:netp:doit:beginnotfound
clienterror(fd, filename, "404", "Not found",
"Tiny couldn't find this file");
return;
} //line:netp:doit:endnotfound
if (is_static) { /* Serve static content */
if (!(S_ISREG(sbuf.st_mode)) || !(S_IRUSR & sbuf.st_mode)) { //line:netp:doit:readable
clienterror(fd, filename, "403", "Forbidden",
"Tiny couldn't read the file");
return;
}
serve_static(fd, filename, sbuf.st_size); //line:netp:doit:servestatic
}
else { /* Serve dynamic content */
if (!(S_ISREG(sbuf.st_mode)) || !(S_IXUSR & sbuf.st_mode)) { //line:netp:doit:executable
clienterror(fd, filename, "403", "Forbidden",
"Tiny couldn't run the CGI program");
return;
}
serve_dynamic(fd, filename, cgiargs); //line:netp:doit:servedynamic
}
}
/* $end doit */
/*
* read_requesthdrs - read and parse HTTP request headers
*/
/* $begin read_requesthdrs */
void read_requesthdrs(rio_t *rp)
{
char buf[MAXLINE];
Rio_readlineb(rp, buf, MAXLINE);
while(strcmp(buf, "\r\n")) { //line:netp:readhdrs:checkterm
Rio_readlineb(rp, buf, MAXLINE);
printf("%s", buf);
}
return;
}
/* $end read_requesthdrs */
/*
* parse_uri - parse URI into filename and CGI args
* return 0 if dynamic content, 1 if static
*/
/* $begin parse_uri */
int parse_uri(char *uri, char *filename, char *cgiargs)
{
char *ptr;
if (!strstr(uri, "cgi-bin")) { /* Static content */ //line:netp:parseuri:isstatic
strcpy(cgiargs, ""); //line:netp:parseuri:clearcgi
strcpy(filename, "."); //line:netp:parseuri:beginconvert1
strcat(filename, uri); //line:netp:parseuri:endconvert1
if (uri[strlen(uri)-1] == '/') //line:netp:parseuri:slashcheck
strcat(filename, "home.html"); //line:netp:parseuri:appenddefault
return 1;
}
else { /* Dynamic content */ //line:netp:parseuri:isdynamic
ptr = index(uri, '?'); //line:netp:parseuri:beginextract
if (ptr) {
strcpy(cgiargs, ptr+1);
*ptr = '\0';
}
else
strcpy(cgiargs, ""); //line:netp:parseuri:endextract
strcpy(filename, "."); //line:netp:parseuri:beginconvert2
strcat(filename, uri); //line:netp:parseuri:endconvert2
return 0;
}
}
/* $end parse_uri */
/*
* serve_static - copy a file back to the client
*/
/* $begin serve_static */
void serve_static(int fd, char *filename, int filesize)
{
int srcfd;
char *srcp, filetype[MAXLINE], buf[MAXBUF];
/* Send response headers to client */
get_filetype(filename, filetype); //line:netp:servestatic:getfiletype
sprintf(buf, "HTTP/1.0 200 OK\r\n"); //line:netp:servestatic:beginserve
sprintf(buf, "%sServer: Tiny Web Server\r\n", buf);
sprintf(buf, "%sContent-length: %d\r\n", buf, filesize);
sprintf(buf, "%sContent-type: %s\r\n\r\n", buf, filetype);
Rio_writen(fd, buf, strlen(buf)); //line:netp:servestatic:endserve
/* Send response body to client */
srcfd = Open(filename, O_RDONLY, 0); //line:netp:servestatic:open
srcp = Mmap(0, filesize, PROT_READ, MAP_PRIVATE, srcfd, 0);//line:netp:servestatic:mmap
Close(srcfd); //line:netp:servestatic:close
Rio_writen(fd, srcp, filesize); //line:netp:servestatic:write
Munmap(srcp, filesize); //line:netp:servestatic:munmap
}
/*
* get_filetype - derive file type from file name
*/
void get_filetype(char *filename, char *filetype)
{
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/jpeg");
else
strcpy(filetype, "text/plain");
}
/* $end serve_static */
/*
* serve_dynamic - run a CGI program on behalf of the client
*/
/* $begin serve_dynamic */
void serve_dynamic(int fd, char *filename, char *cgiargs)
{
char buf[MAXLINE], *emptylist[] = { NULL };
/* Return first part of HTTP response */
sprintf(buf, "HTTP/1.0 200 OK\r\n");
Rio_writen(fd, buf, strlen(buf));
sprintf(buf, "Server: Tiny Web Server\r\n");
Rio_writen(fd, buf, strlen(buf));
if (Fork() == 0) { /* child */ //line:netp:servedynamic:fork
/* Real server would set all CGI vars here */
setenv("QUERY_STRING", cgiargs, 1); //line:netp:servedynamic:setenv
Dup2(fd, STDOUT_FILENO); /* Redirect stdout to client */ //line:netp:servedynamic:dup2
Execve(filename, emptylist, environ); /* Run CGI program */ //line:netp:servedynamic:execve
}
Wait(NULL); /* Parent waits for and reaps child */ //line:netp:servedynamic:wait
}
/* $end serve_dynamic */
/*
* clienterror - returns an error message to the client
*/
/* $begin clienterror */
void clienterror(int fd, char *cause, char *errnum,
char *shortmsg, char *longmsg)
{
char buf[MAXLINE], body[MAXBUF];
/* Build the HTTP response body */
sprintf(body, "<html><title>Tiny Error</title>");
sprintf(body, "%s<body bgcolor=""ffffff"">\r\n", body);
sprintf(body, "%s%s: %s\r\n", body, errnum, shortmsg);
sprintf(body, "%s<p>%s: %s\r\n", body, longmsg, cause);
sprintf(body, "%s<hr><em>The Tiny Web server</em>\r\n", body);
/* Print the HTTP response */
sprintf(buf, "HTTP/1.0 %s %s\r\n", errnum, shortmsg);
Rio_writen(fd, buf, strlen(buf));
sprintf(buf, "Content-type: text/html\r\n");
Rio_writen(fd, buf, strlen(buf));
sprintf(buf, "Content-length: %d\r\n\r\n", (int)strlen(body));
Rio_writen(fd, buf, strlen(buf));
Rio_writen(fd, body, strlen(body));
}
/* $end clienterror */