1 files changed, 186 insertions, 0 deletions
diff --git a/lib/private/LargeFileHelper.php b/lib/private/LargeFileHelper.php
new file mode 100755
index 00000000000..fa4c72da756
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+++ b/lib/private/LargeFileHelper.php
@@ -0,0 +1,186 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OC;
+
+use bantu\IniGetWrapper\IniGetWrapper;
+
+/**
+ * Helper class for large files on 32-bit platforms.
+ */
+class LargeFileHelper {
+	/**
+	 * pow(2, 53) as a base-10 string.
+	 * @var string
+	 */
+	public const POW_2_53 = '9007199254740992';
+
+	/**
+	 * pow(2, 53) - 1 as a base-10 string.
+	 * @var string
+	 */
+	public const POW_2_53_MINUS_1 = '9007199254740991';
+
+	/**
+	 * @brief Checks whether our assumptions hold on the PHP platform we are on.
+	 *
+	 * @throws \RuntimeException if our assumptions do not hold on the current
+	 *                           PHP platform.
+	 */
+	public function __construct() {
+		$pow_2_53 = (float)self::POW_2_53_MINUS_1 + 1.0;
+		if ($this->formatUnsignedInteger($pow_2_53) !== self::POW_2_53) {
+			throw new \RuntimeException(
+				'This class assumes floats to be double precision or "better".'
+			);
+		}
+	}
+
+	/**
+	 * @brief Formats a signed integer or float as an unsigned integer base-10
+	 *        string. Passed strings will be checked for being base-10.
+	 *
+	 * @param int|float|string $number Number containing unsigned integer data
+	 *
+	 * @throws \UnexpectedValueException if $number is not a float, not an int
+	 *                                   and not a base-10 string.
+	 *
+	 * @return string Unsigned integer base-10 string
+	 */
+	public function formatUnsignedInteger(int|float|string $number): string {
+		if (is_float($number)) {
+			// Undo the effect of the php.ini setting 'precision'.
+			return number_format($number, 0, '', '');
+		} elseif (is_string($number) && ctype_digit($number)) {
+			return $number;
+		} elseif (is_int($number)) {
+			// Interpret signed integer as unsigned integer.
+			return sprintf('%u', $number);
+		} else {
+			throw new \UnexpectedValueException(
+				'Expected int, float or base-10 string'
+			);
+		}
+	}
+
+	/**
+	 * @brief Tries to get the size of a file via various workarounds that
+	 *        even work for large files on 32-bit platforms.
+	 *
+	 * @param string $filename Path to the file.
+	 *
+	 * @return int|float Number of bytes as number (float or int)
+	 */
+	public function getFileSize(string $filename): int|float {
+		$fileSize = $this->getFileSizeViaCurl($filename);
+		if (!is_null($fileSize)) {
+			return $fileSize;
+		}
+		$fileSize = $this->getFileSizeViaExec($filename);
+		if (!is_null($fileSize)) {
+			return $fileSize;
+		}
+		return $this->getFileSizeNative($filename);
+	}
+
+	/**
+	 * @brief Tries to get the size of a file via a CURL HEAD request.
+	 *
+	 * @param string $fileName Path to the file.
+	 *
+	 * @return null|int|float Number of bytes as number (float or int) or
+	 *                        null on failure.
+	 */
+	public function getFileSizeViaCurl(string $fileName): null|int|float {
+		if (\OC::$server->get(IniGetWrapper::class)->getString('open_basedir') === '') {
+			$encodedFileName = rawurlencode($fileName);
+			$ch = curl_init("file:///$encodedFileName");
+			curl_setopt($ch, CURLOPT_NOBODY, true);
+			curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+			curl_setopt($ch, CURLOPT_HEADER, true);
+			$data = curl_exec($ch);
+			curl_close($ch);
+			if ($data !== false) {
+				$matches = [];
+				preg_match('/Content-Length: (\d+)/', $data, $matches);
+				if (isset($matches[1])) {
+					return 0 + $matches[1];
+				}
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * @brief Tries to get the size of a file via an exec() call.
+	 *
+	 * @param string $filename Path to the file.
+	 *
+	 * @return null|int|float Number of bytes as number (float or int) or
+	 *                        null on failure.
+	 */
+	public function getFileSizeViaExec(string $filename): null|int|float {
+		if (\OCP\Util::isFunctionEnabled('exec')) {
+			$os = strtolower(php_uname('s'));
+			$arg = escapeshellarg($filename);
+			$result = null;
+			if (str_contains($os, 'linux')) {
+				$result = $this->exec("stat -c %s $arg");
+			} elseif (str_contains($os, 'bsd') || str_contains($os, 'darwin')) {
+				$result = $this->exec("stat -f %z $arg");
+			}
+			return $result;
+		}
+		return null;
+	}
+
+	/**
+	 * @brief Gets the size of a file via a filesize() call and converts
+	 *        negative signed int to positive float. As the result of filesize()
+	 *        will wrap around after a file size of 2^32 bytes = 4 GiB, this
+	 *        should only be used as a last resort.
+	 *
+	 * @param string $filename Path to the file.
+	 *
+	 * @return int|float Number of bytes as number (float or int).
+	 */
+	public function getFileSizeNative(string $filename): int|float {
+		$result = filesize($filename);
+		if ($result < 0) {
+			// For file sizes between 2 GiB and 4 GiB, filesize() will return a
+			// negative int, as the PHP data type int is signed. Interpret the
+			// returned int as an unsigned integer and put it into a float.
+			return (float)sprintf('%u', $result);
+		}
+		return $result;
+	}
+
+	/**
+	 * Returns the current mtime for $fullPath
+	 */
+	public function getFileMtime(string $fullPath): int {
+		try {
+			$result = filemtime($fullPath) ?: -1;
+		} catch (\Exception $e) {
+			$result = - 1;
+		}
+		if ($result < 0) {
+			if (\OCP\Util::isFunctionEnabled('exec')) {
+				$os = strtolower(php_uname('s'));
+				if (str_contains($os, 'linux')) {
+					return (int)($this->exec('stat -c %Y ' . escapeshellarg($fullPath)) ?? -1);
+				}
+			}
+		}
+		return $result;
+	}
+
+	protected function exec(string $cmd): null|int|float {
+		$result = trim(exec($cmd));
+		return ctype_digit($result) ? 0 + $result : null;
+	}
+}