11.11

--- tiny.origin.c	2021-02-25 07:26:33.302592754 +0000
+++ tiny.11.c	2021-02-25 07:26:33.302592754 +0000
@@ -7,9 +7,9 @@
 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 serve_static(int fd, char *filename, int filesize, char *method);
 void get_filetype(char *filename, char *filetype);
-void serve_dynamic(int fd, char *filename, char *cgiargs);
+void serve_dynamic(int fd, char *filename, char *cgiargs, char *method);
 void clienterror(int fd, char *cause, char *errnum,
     char *shortmsg, char *longmsg);
 
@@ -55,7 +55,7 @@
     return;
   printf("%s", buf);
   sscanf(buf, "%s %s %s", method, uri, version);       //line:netp:doit:parserequest
-  if (strcasecmp(method, "GET")) {                     //line:netp:doit:beginrequesterr
+  if (!(strcasecmp(method, "GET") == 0 || strcasecmp(method, "HEAD") == 0)) {
     clienterror(fd, method, "501", "Not Implemented",
         "Tiny does not implement this method");
     return;
@@ -76,7 +76,7 @@
           "Tiny couldn't read the file");
       return;
     }
-    serve_static(fd, filename, sbuf.st_size);        //line:netp:doit:servestatic
+    serve_static(fd, filename, sbuf.st_size, method);        //line:netp:doit:servestatic
   }
   else { /* Serve dynamic content */
     if (!(S_ISREG(sbuf.st_mode)) || !(S_IXUSR & sbuf.st_mode)) { //line:netp:doit:executable
@@ -84,7 +84,7 @@
           "Tiny couldn't run the CGI program");
       return;
     }
-    serve_dynamic(fd, filename, cgiargs);            //line:netp:doit:servedynamic
+    serve_dynamic(fd, filename, cgiargs, method);            //line:netp:doit:servedynamic
   }
 }
 
@@ -136,7 +136,7 @@
 /*
  * serve_static - copy a file back to the client
  */
-void serve_static(int fd, char *filename, int filesize)
+void serve_static(int fd, char *filename, int filesize, char *method)
 {
   int srcfd;
   char *srcp, filetype[MAXLINE], buf[MAXBUF];
@@ -152,6 +152,9 @@
   printf("Response headers:\n");
   printf("%s", buf);
 
+  if (strcasecmp(method, "HEAD") == 0)
+    return;
+
   /* 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
@@ -180,7 +183,7 @@
 /*
  * serve_dynamic - run a CGI program on behalf of the client
  */
-void serve_dynamic(int fd, char *filename, char *cgiargs)
+void serve_dynamic(int fd, char *filename, char *cgiargs, char *method)
 {
   char buf[MAXLINE], *emptylist[] = { NULL };
 
@@ -193,6 +196,7 @@
   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
+    setenv("REQUEST_METHOD", method, 1);
     Dup2(fd, STDOUT_FILENO);         /* Redirect stdout to client */ //line:netp:servedynamic:dup2
     Execve(filename, emptylist, environ); /* Run CGI program */ //line:netp:servedynamic:execve
   }

/*
 * head-adder.c - a minimal CGI program that adds two numbers together
 */
#include "../csapp.h"

int main(void) {
  char *buf, *p, *method;
  char arg1[MAXLINE], arg2[MAXLINE], content[MAXLINE];
  int n1=0, n2=0;

  /* Extract the two arguments */
  if ((buf = getenv("QUERY_STRING")) != NULL) {
    p = strchr(buf, '&');
    *p = '\0';
    strcpy(arg1, buf);
    strcpy(arg2, p+1);
    n1 = atoi(arg1);
    n2 = atoi(arg2);
  }

  method = getenv("REQUEST_METHOD");

  /* Make the response body */
  sprintf(content, "Welcome to add.com: ");
  sprintf(content, "%sTHE Internet addition portal.\r\n<p>", content);
  sprintf(content, "%sThe answer is: %d + %d = %d\r\n<p>",
      content, n1, n2, n1 + n2);
  sprintf(content, "%sThanks for visiting!\r\n", content);

  /* Generate the HTTP response */
  printf("Connection: close\r\n");
  printf("Content-length: %d\r\n", (int)strlen(content));
  printf("Content-type: text/html\r\n\r\n");

  if (strcasecmp(method, "HEAD") != 0)
    printf("%s", content);

  fflush(stdout);

  exit(0);
}