pset6 (server.c) - 404 not found with /cat.jpg, but works with other files

Question

I have been having trouble with server.c

My version seems to work with hello.html. However, when I try and use the following with telnet

GET /cat.jpg HTML/1.1

I get HTTP/1.1 404 file not found

Then, through gdb, I found that the path is correct for files such as hello.html, but is incorrect for cat.jpg

(gdb) print path
$1 = 0xbfffee60 "/home/jharvard/Dropbox/Medical School/CS50/pset6/public/cat.jpg\b"

I am unsure where the "\b" is coming from, as it doesn't occur with hello.html. Below is (I think) the relevant code around absolute path and path.

        // extract absolutepath
        char absolutepath[strlen(request_target) - strlen(query)];
        if (query == NULL)
        {
            strcpy(absolutepath, request_target);
        }
        else
        {
            strncpy(absolutepath, request_target, strlen(request_target)-strlen(query));  
        } 

        // validate absolutepath
        if (strchr(absolutepath, '.') == NULL)          // need to have a '.'
        {
            error(501);
            continue;
        }

        // TODO: concatenate root and absolute-path
        char path[strlen(root) + strlen(absolutepath)];
        strcpy(path, root);
        strcat(path, absolutepath);

        // TODO: ensure path exists
        if (access(path, F_OK) == -1)
        {
            error(404);
            continue;
        }

        // TODO: ensure path is readable
        if (access(path, R_OK) == -1)
        {
            error(403);
            continue;
        }

Also, it seemed that in other questions, the dprintf was the problem, so here is mine below

            // TODO: respond to client
            if (dprintf(cfd, "HTTP/1.1 200 OK\r\n") < 0)
            {
                continue;
            }
            if (dprintf(cfd, "Connection: close\r\n") < 0)
            {
                continue;
            }
            if (dprintf(cfd, "Content-Length: %i\r\n", length) < 0)
            {
                continue;
            }
            if (dprintf(cfd, "Content-Type: %s\r\n\r\n", type) < 0)
            {
                continue;
            }
            if (write(cfd, body, length) == -1)
            {
                continue;
            }

Thanks for any help in the matter.

Answer 1

I solved the problem on mine. Basically the error was introduced because my declaration of absoluteTarget had an extra space. That is, you need your strings exactly the right length. I found this by looking back in GDB until I found the line where the \b was added.

One thing I can see in yours, it doesn't look like you're adding null terminators to your strings. That could cause some problems. For example, absolute-path you have strlens of request-target - query. Well, that should give you the number of CHARACTERS in absolute path... but the SIZE of absolute-path should be that plus 1 for the null terminator.

Answer 2

From what you printed above, the path to cat.jpg is has also the second space of the request, maybe that's about how you are extracting the path from request.