Pset6 load returns length zero for php files

Question

First time posting so if I'm off the mark here let me know.

Basically, in writing server.c I can't figure out how to test my load function now that I've written it. check50 will only work once I've completed the writing the entire program. I was using check50 but when using curl it doesn't stop on the break points set at load. Needless to say, I'm a bit stuck on load because I haven't been able to check it. This is what I've got if it helps:

Load:

bool load(FILE* file, BYTE** content, size_t* length) {

    if (file == NULL){
        return false;  
    } 

    BYTE buffer[BYTES];
    size_t numBytes = fread(buffer, sizeof(buffer), 1, file);
    *content = &buffer[0];
    *length = numBytes;
    printf("%zu\n", numBytes);
    return false;
}

I realize that this function is NOT efficient as I'm doing this one byte at a time. However, to be clear, I need to be able to run check50 (or similar) so I can stop the program to inspect my values in order to evaluate what is happening. All of the my check50 statements fail on the server2 check and all of my server1 pass.

I have checked through the forums for the last hour trying to find an answer before posting. Thank you to whoever helps. Been on this for a while now.

EDIT: I changed the load function to the below. It now passes all cs50 checks but returns a file size of zero only for my php files. All of the other files in the public director run correctly and I get a error 500 only on the php file. Because this error may be coming from somewhere other than my load function I also posted here my parse function. I did verify that the lookup() function is returning the correct type but am posting that also just in case:

Load:

bool load(FILE* file, BYTE** content, size_t* length)
{
    // TODO
    int fd = fileno(file);
    struct stat st;
    int suc = fstat(fd, &st);
    if (suc != 0){
        error(500);
        printf("%d", suc);    
    }

    int size = st.st_size;

    *content = malloc(size + 1);
    fread(*content, size, 1, file);
    printf("%d\n",size);
    *length = size;
    return true;

}

I previously tried to use fseek() and ftell() but would give me a seg fault, again only on the php file.

PARSE AND LOOKUP FUNCTIONS REMOVED FROM POST

Greatly appreciate any and all help. Hope to get an answer soon so I can take the code down. Thanks!

Directory tree:

.
├── Makefile
├── myserver
├── myserver.c
├── public
│   ├── cat.html
│   ├── cat.jpg
│   ├── favicon.ico
│   ├── hello.html
│   ├── hello.php
│   ├── index.php
│   └── test
│       └── index.html
├── server
├── server.c
└── server2.c

File permissions:

-rw-rw-r-- 1 ubuntu ubuntu   156 Oct 24  2015 cat.html
-rw-rw-r-- 1 ubuntu ubuntu 26860 Oct 24  2015 cat.jpg
-rw-rw-r-- 1 ubuntu ubuntu   318 Oct 24  2015 favicon.ico
-rw-rw-r-- 1 ubuntu ubuntu   316 Oct 24  2015 hello.html
-rw-rw-r-- 1 ubuntu ubuntu   281 Oct 24  2015 hello.php

Answer 1

You would need to use debug50 or gdb to "stop the program and inspect", not check50.

Since you are asking for help with debugging, my comments are intentionally cryptic.

If load returns false, you will get a 500 error. Without using gdb et.al. review your function and find the place where it returns true.

debug50/gdb should make it clear that load will not work on any file bigger than 512 bytes. load (generally) requires a realloc.

And sometimes a good load function will fail because of memory leaks in another function. valgrind is the tool for that. You can use this call to valgrind valgrind -v --leak-check=full --show-leak-kinds=all --track-origins=yes to get detailed feedback.

Addendum after edit:

You cannot use fseek or ftell on a pipe, backup info here. From the spec:

Odds are you’re unfamiliar with popen. That function opens a "pipe" to a process (php-cgi in our case), which provides us with a FILE pointer via which we can read that process’s standard output (as though it were an actual file).

From man 2 stat (emphasis added):

The st_size field gives the size of the file (if it is a regular file or a symbolic link) in bytes. The size of a symbolic link is the length of the pathname it contains, without a terminating null byte.

So one can assume st_size will not give the size of a pipe.

load (generally) requires a realloc.