Fatal error: session_start(): Failed to initialize storage module: files问题解决方法_php技巧

之前编译安装的LNMP环境+phpmyamdin4.02的版本，今天突然出现这个问题：

Fatal error: session_start(): Failed to initialize storage module: files (path: ) in /data/www/phpmyadmin/libraries/session.inc.php on line 83

大致意思是session会话初始化的时候储存路径有误！第一反应就是查看php.ini的配置文件中的：

session.save_path = "/tmp"

默认前面是加的分号，表示不启用，我之前配置的时候已经启用了。那为什么还会报错呢？，于是网上找了一些资料，感觉都千篇一律：

1、检查error.log(Apache2.2\logs)文件，查看是否有错误报告。未发现。
2、检查php.ini中的session.save_handler的值是否为files，如果不是改为files
3、检查php.ini文件中session.save_path是否被注释了，如果有，则去掉前面的”;”。
4、将save_path后面的路径改成已有的路径，比如”D:\php\temp”
5、检查temp文件夹的属性是否可读可写。
6、重启APACHE服务器。OK

不知道那些哥们转载的时候自己试过了没有（在这里喷一下，最讨厌那种自己都没有亲测，就一股脑的转来转去。一点都不负责!）
根据上面的流程，排查了之后发现压根就没有解决，不过小编的服务器是nginx非apache。
然后自己写了一个脚本test.php：

$r = session_start();
var_dump($r);

打印结果为：

Warning: session_start(): SAFE MODE Restriction in effect. The script whose uid is 501 is not allowed to access /tmp owned by uid 0 in /data/www/test.php on line 3 Fatal error: session_start(): Failed to initialize storage module: files (path: ) in /data/www/test.php on line 3

意思是 php5一个安全模式的bug，默认session的save_path是系统的临时目录，这样会要校验权限。而这个脚本不能通过/tmp拥有者uid为0来执行uid是501也是www用户组的权限
解决这个有两种解决方法：

1.关闭安全模式；
2.在命令行下chown改文件/目录的拥有者

当然两种方法都要求你有服务器的权限。
下面是示例php.ini的配置文件：

[Session]
; Handler used to store/retrieve data.
; http://php.net/session.save-handler
session.save_handler = files; Argument passed to save_handler. In the case of files, this is the path
; where data files are stored. Note: Windows users have to change this
; variable in order to use PHP's session functions.

; The path can be defined as:

; session.save_path = "N;/path"

; where N is an integer. Instead of storing all the session files in
; /path, what this will do is use subdirectories N-levels deep, and
; store the session data in those directories. This is useful if you
; or your OS have problems with lots of files in one directory, and is
; a more efficient layout for servers that handle lots of sessions.

; NOTE 1: PHP will not create this directory structure automatically.
; You can use the script in the ext/session dir for that purpose.
; NOTE 2: See the section on garbage collection below if you choose to
; use subdirectories for session storage

; The file storage module creates files using mode 600 by default.
; You can change that by using

; session.save_path = "N;MODE;/path"

; where MODE is the octal representation of the mode. Note that this
; does not overwrite the process's umask.
; http://php.net/session.save-path
session.save_path = "/tmp"
; Whether to use cookies.
; http://php.net/session.use-cookies
session.use_cookies = 1
; http://php.net/session.cookie-secure
;session.cookie_secure =
; This option forces PHP to fetch and use a cookie for storing and maintaining
; the session id. We encourage this operation as it's very helpful in combatting
; session hijacking when not specifying and managing your own session id. It is
; not the end all be all of session hijacking defense, but it's a good start.
; http://php.net/session.use-only-cookies
session.use_only_cookies = 1
; Name of the session (used as cookie name).
; http://php.net/session.name
session.name = PHPSESSID
; Initialize session on request startup.
; http://php.net/session.auto-start
session.auto_start = 0
; Lifetime in seconds of cookie or, if 0, until browser is restarted.
; http://php.net/session.cookie-lifetime
session.cookie_lifetime = 0
; The path for which the cookie is valid.
; http://php.net/session.cookie-path
session.cookie_path = /
; The domain for which the cookie is valid.
; http://php.net/session.cookie-domain
session.cookie_domain =
; Whether or not to add the httpOnly flag to the cookie, which makes it inaccessible to browser scripting languages such as JavaScript.
; http://php.net/session.cookie-httponly
session.cookie_httponly =
; Handler used to serialize data. php is the standard serializer of PHP.
; http://php.net/session.serialize-handler
session.serialize_handler = php
; Defines the probability that the 'garbage collection' process is started
; on every session initialization. The probability is calculated by using
; gc_probability/gc_divisor. Where session.gc_probability is the numerator
; and gc_divisor is the denominator in the equation. Setting this value to 1
; when the session.gc_divisor value is 100 will give you approximately a 1% chance
; the gc will run on any give request.
; Default Value: 1
; Development Value: 1
; Production Value: 1
; http://php.net/session.gc-probability
session.gc_probability = 1
; Defines the probability that the 'garbage collection' process is started on every
; session initialization. The probability is calculated by using the following equation:
; gc_probability/gc_divisor. Where session.gc_probability is the numerator and
; session.gc_divisor is the denominator in the equation. Setting this value to 1
; when the session.gc_divisor value is 100 will give you approximately a 1% chance
; the gc will run on any give request. Increasing this value to 1000 will give you
; a 0.1% chance the gc will run on any give request. For high volume production servers,
; this is a more efficient approach.
; Default Value: 100
; Development Value: 1000
; Production Value: 1000
; http://php.net/session.gc-divisor
session.gc_divisor = 1000
; After this number of seconds, stored data will be seen as 'garbage' and
; cleaned up by the garbage collection process.
; http://php.net/session.gc-maxlifetime
session.gc_maxlifetime = 1440
; NOTE: If you are using the subdirectory option for storing session files
; (see session.save_path above), then garbage collection does *not*
; happen automatically. You will need to do your own garbage
; collection through a shell script, cron entry, or some other method.
; For example, the following script would is the equivalent of
; setting session.gc_maxlifetime to 1440 (1440 seconds = 24 minutes):
; find /path/to/sessions -cmin +24 | xargs rm
; PHP 4.2 and less have an undocumented feature/bug that allows you to
; to initialize a session variable in the global scope, even when register_globals
; is disabled. PHP 4.3 and later will warn you, if this feature is used.
; You can disable the feature and the warning separately. At this time,
; the warning is only displayed, if bug_compat_42 is enabled. This feature
; introduces some serious security problems if not handled correctly. It's
; recommended that you do not use this feature on production servers. But you
; should enable this on development servers and enable the warning as well. If you
; do not enable the feature on development servers, you won't be warned when it's
; used and debugging errors caused by this can be difficult to track down.
; Default Value: On
; Development Value: On
; Production Value: Off
; http://php.net/session.bug-compat-42
session.bug_compat_42 = Off
; This setting controls whether or not you are warned by PHP when initializing a
; session value into the global space. session.bug_compat_42 must be enabled before
; these warnings can be issued by PHP. See the directive above for more information.
; Default Value: On
; Development Value: On
; Production Value: Off
; http://php.net/session.bug-compat-warn
session.bug_compat_warn = Off
; Check HTTP Referer to invalidate externally stored URLs containing ids.
; HTTP_REFERER has to contain this substring for the session to be
; considered as valid.
; http://php.net/session.referer-check
session.referer_check =
; How many bytes to read from the file.
; http://php.net/session.entropy-length
session.entropy_length = 0
; Specified here to create the session id.
; http://php.net/session.entropy-file
; On systems that don't have /dev/urandom /dev/arandom can be used
; On windows, setting the entropy_length setting will activate the
; Windows random source (using the CryptoAPI)
;session.entropy_file = /dev/urandom
; Set to {nocache,private,public,} to determine HTTP caching aspects
; or leave this empty to avoid sending anti-caching headers.
; http://php.net/session.cache-limiter
session.cache_limiter = nocache
; Document expires after n minutes.
; http://php.net/session.cache-expire
session.cache_expire = 180
; trans sid support is disabled by default.
; Use of trans sid may risk your users security.
; Use this option with caution.
; - User may send URL contains active session ID
; to other person via. email/irc/etc.
; - URL that contains active session ID may be stored
; in publically accessible computer.
; - User may access your site with the same session ID
; always using URL stored in browser's history or bookmarks.
; http://php.net/session.use-trans-sid
session.use_trans_sid = 0
; Select a hash function for use in generating session ids.
; Possible Values
; 0 (MD5 128 bits)
; 1 (SHA-1 160 bits)
; This option may also be set to the name of any hash function supported by
; the hash extension. A list of available hashes is returned by the hash_algos()
; function.
; http://php.net/session.hash-function
session.hash_function = 0
; Define how many bits are stored in each character when converting
; the binary hash data to something readable.
; Possible values:
; 4 (4 bits: 0-9, a-f)
; 5 (5 bits: 0-9, a-v)
; 6 (6 bits: 0-9, a-z, A-Z, "-", ",")
; Default Value: 4
; Development Value: 5
; Production Value: 5
; http://php.net/session.hash-bits-per-character
session.hash_bits_per_character = 5
; The URL rewriter will look for URLs in a defined set of HTML tags.
; form/fieldset are special; if you include them here, the rewriter will
; add a hidden field with the info which is otherwise appended
; to URLs. If you want XHTML conformity, remove the form entry.
; Note that all valid entries require a "=", even if no value follows.
; Default Value: "a=href,area=href,frame=src,form=,fieldset="
; Development Value: "a=href,area=href,frame=src,input=src,form=fakeentry"
; Production Value: "a=href,area=href,frame=src,input=src,form=fakeentry"
; http://php.net/url-rewriter.tags
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"

因为这个是在一台VPS上面配置的，上面有多个项目，于是小编打开一个项目，发现此项目的验证码功能是OK的。
于是查看代码如下：

$sessSavePath = "/data/sessions/";
// Session保存路径
if(is_writeable($sessSavePath) && is_readable($sessSavePath)){ session_save_path($sessSavePath); }
if(!empty($cfg_domain_cookie)) session_set_cookie_params(0,'/',$cfg_domain_cookie);

上面这个代码是在session_start() 初始化之前来判断是否存在session会话的文件夹。
于是就在phpmyadmin里面的保存的那个文件/phpmyadmin/libraries/session.inc.php做了下修改:

if (! isset($_COOKIE[$session_name])) {
// on first start of session we check for errors
// f.e. session dir cannot be accessed - session file not created
$orig_error_count = $GLOBALS['error_handler']->countErrors();
//session_save_path('./tmp');
session_save_path("/data/www/session");
$r = session_start();
if ($r !== true
|| $orig_error_count != $GLOBALS['error_handler']->countErrors()
) {
setcookie($session_name, '', 1);
/*
* Session initialization is done before selecting language, so we
* can not use translations here.
*/
PMA_fatalError('Cannot start session without errors, please check errors given in your PHP and/or webserver log file and configure your PHP installation properly. Also ensure that cookies are enabled in your browser.');
}
unset($orig_error_count);
} else {
session_save_path("/data/www/session");
session_start();
}

在 session_start(); 前面添加了 session_save_path(“/data/www/session”); 就解决了这个问题。
切记通过@ini_set(‘session.save_path', ”/data/www/session”);无效！
这个问题困扰了我几个小时，终于解决了，所以就记录下来，对日后应该会有帮助。