file_put_contents truncates content to max int on 32-bit php

Question

I have nextcloud running on my Raspberry Pi 4, which uses 32-bit architecture.

When trying to upload a file larger then 2147483647 bytes, the file is uploaded completely and is accessible through ssh. However when I try to access it in any way through the webclient it fails. The error seen in the webclient's logging is the following:

file_put_contents(): content truncated from 4118394086 to 2147483647 bytes at /var/www/html/nextcloud/lib/private/Files/Storage/Local.php#556

When I try to access the file this error message is logged:

Sabre\DAV\Exception\RequestedRangeNotSatisfiable: The start offset (0) exceeded the size of the entity (-176573210)

The file in question here is a .mp4 file, however i have been able to replicate the issue with other filetypes.

I have read that the 2GB upload limit for 32-bit architectures has been fixed, however I don't know why it might fail in my case.

Answer 1

Problem

Well you cant get around this by tweaking any config, since its a hard limit set by PHP (PHP_INT_MAX on 32-Bit architecure is 2G (2^(32-1)-1))

There is hope

You can patch manually or even better override the responsible nextcloud code:

patch manually (since you are not using composer this is what you probably wanna do)

// this one is pretty memory expensive, but works with resouce and string
// Test: 4GB file, 2GB chunks (at 32bits)
// 12GB memory usage! - hell no
public function file_put_contents($path, $data) {
    $bytesWritten = 0;
    foreach (explode(PHP_EOL, chunk_split($data, PHP_INT_MAX, PHP_EOL)) as $chunk) {
        $bytesWritten += file_put_contents($this->getSourcePath($path), $chunk, FILE_APPEND|LOCK_EX);
    }
    
    return $bytesWritten;
}

or

// better use this, in case $data is a resource - I dont know, you have to test it!
// Test: 4GB file, 1MB chunks
// 2MB memory usage - much better :)
public function file_put_contents($path, $data) {
    $bytesWritten = 0;
    while ($chunk = fread($data, 2**20)) {
        $bytesWritten += file_put_contents($this->getSourcePath($path), $chunk, FILE_APPEND|LOCK_EX);
    }

    return $bytesWritten;
}

In case you want to override (composer)

class PatchedLocal extends OC\Files\Storage\Local {
    public function file_put_contents($path, $data) {
        // same as above ...
    }
}

And here everything you need to know to force the autoloader to use your PatchedLocal. - As mentioned, you want to use composers PSR-4 implementation for this - via composer.json.