various fixes for Spring 2021

- support for 206 return code
- fixes to sendfile
- add URL variable to testloginapi.sh

src/bufio.c

@@ -108,6 +108,9 @@ read_more(struct bufio *self)
 /* Given an offset into the buffer, return a char *.
  * This pointer will be valid only until the next call 
  * to any of the bufio_read* function.
+ *
+ * The returned pointer is not guaranteed to point to a
+ * zero-terminated string.
  */
 char * 
 bufio_offset2ptr(struct bufio *self, size_t offset)
@@ -194,7 +197,7 @@ bufio_read(struct bufio *self, size_t count, size_t *buf_offset)
  * See sendfile(2) for return value.
  */
 ssize_t
-bufio_sendfile(struct bufio *self, int fd, off_t *off, int filesize)
+bufio_sendfile(struct bufio *self, int fd, off_t *off, size_t filesize)
 {
     return sendfile(self->socket, fd, off, filesize);
 }

src/bufio.h

@@ -13,7 +13,7 @@ ssize_t bufio_readline(struct bufio *self, size_t *line_offset);
 ssize_t bufio_read(struct bufio *self, size_t count, size_t *buf_offset);
 char * bufio_offset2ptr(struct bufio *self, size_t offset);
 size_t bufio_ptr2offset(struct bufio *self, char *ptr);
-ssize_t bufio_sendfile(struct bufio *self, int fd, off_t *off, int filesize);
+ssize_t bufio_sendfile(struct bufio *self, int fd, off_t *off, size_t filesize);
 ssize_t bufio_sendbuffer(struct bufio *self, buffer_t *response);
 
 #endif /* _BUFIO_H */

src/http.c

@@ -28,6 +28,7 @@
 
 // Need macros here because of the sizeof
 #define CRLF "\r\n"
+#define CR "\r"
 #define STARTS_WITH(field_name, header) \
     (!strncasecmp(field_name, header, sizeof(header) - 1))
 
@@ -41,6 +42,7 @@ http_parse_request(struct http_transaction *ta)
         return false;
 
     char *request = bufio_offset2ptr(ta->client->bufio, req_offset);
+    request[len-2] = '\0';  // replace LF with 0 to ensure zero-termination
     char *endptr;
     char *method = strtok_r(request, " ", &endptr);
     if (method == NULL)
@@ -59,10 +61,11 @@ http_parse_request(struct http_transaction *ta)
 
     ta->req_path = bufio_ptr2offset(ta->client->bufio, req_path);
 
-    char *http_version = strtok_r(NULL, CRLF, &endptr);
+    char *http_version = strtok_r(NULL, CR, &endptr);
     if (http_version == NULL)  // would be HTTP 0.9
         return false;
 
+    // record client's HTTP version in request
     if (!strcmp(http_version, "HTTP/1.1"))
         ta->req_version = HTTP_1_1;
     else if (!strcmp(http_version, "HTTP/1.0"))
@@ -97,7 +100,7 @@ http_process_headers(struct http_transaction *ta)
         char *field_name = strtok_r(header, ":", &endptr);
         char *field_value = strtok_r(NULL, " \t", &endptr);    // skip leading & trailing OWS
 
-        if (field_name == NULL)
+        if (field_name == NULL || field_value == NULL)
             return false;
 
         // printf("Header: %s: %s\n", field_name, field_value);
@@ -147,6 +150,9 @@ start_response(struct http_transaction * ta, buffer_t *res)
     case HTTP_OK:
         buffer_appends(res, "200 OK");
         break;
+    case HTTP_PARTIAL_CONTENT:
+        buffer_appends(res, "206 Partial Content");
+        break;
     case HTTP_BAD_REQUEST:
         buffer_appends(res, "400 Bad Request");
         break;
@@ -295,20 +301,26 @@ handle_static_asset(struct http_transaction *ta, char *basedir)
     }
 
     ta->resp_status = HTTP_OK;
-    add_content_length(&ta->resp_headers, st.st_size);
     http_add_header(&ta->resp_headers, "Content-Type", "%s", guess_mime_type(fname));
+    off_t from = 0, to = st.st_size - 1;
+
+    off_t content_length = to + 1 - from;
+    add_content_length(&ta->resp_headers, content_length);
 
     bool success = send_response_header(ta);
     if (!success)
         goto out;
 
-    success = bufio_sendfile(ta->client->bufio, filefd, NULL, st.st_size) == st.st_size;
+    // sendfile may send fewer bytes than requested, hence the loop
+    while (success && from <= to)
+        success = bufio_sendfile(ta->client->bufio, filefd, &from, to + 1 - from) > 0;
+
 out:
     close(filefd);
     return success;
 }
 
-static int
+static bool
 handle_api(struct http_transaction *ta)
 {
     return send_error(ta, HTTP_NOT_FOUND, "API not implemented");

src/http.h

@@ -20,6 +20,7 @@ enum http_version {
 
 enum http_response_status {
     HTTP_OK = 200,
+    HTTP_PARTIAL_CONTENT = 206,
     HTTP_BAD_REQUEST = 400,
     HTTP_PERMISSION_DENIED = 403,
     HTTP_NOT_FOUND = 404,

src/testloginapi.sh

@@ -2,8 +2,13 @@
 # change this as per instruction to avoid conflicts.
 PORT=10000
 
+# to test against a working implementation (and see the intended responses)
+# change this URL=http://theta.cs.vt.edu:3000/
+URL=http://localhost:${PORT}
+
 COOKIEJAR=cookies.txt
 
+
 # clear cookies
 /bin/rm ${COOKIEJAR}
 
@@ -12,20 +17,20 @@ curl -v -H "Content-Type: application/json" \
      -c ${COOKIEJAR} \
      -X POST \
      -d '{"username":"user0","password":"thepassword"}' \
-    http://localhost:${PORT}/api/login
+    ${URL}/api/login
 
 # this should succeed if the password is correct
 curl -v \
     -b ${COOKIEJAR} \
-    http://localhost:${PORT}/api/login
+    ${URL}/api/login
 
 # create a 'private' folder first.
 # this should fail since credentials were not presented
 curl -v \
-    http://localhost:${PORT}/private/secret.txt
+    ${URL}/private/secret.txt
 
 # this should succeed since credentials were presented
 curl -v \
     -b ${COOKIEJAR} \
-    http://localhost:${PORT}/private/secret.txt
+    ${URl}/private/secret.txt