It should be noted that this function performs access checks based on the real UID and real GID of the process running PHP. These aren't necessarily the same as the effective UID and GID.
In other words, it may well be that access() returns “true” for a particular permission, but an fopen() operation which requires the same permission will fail, and vice versa.
Keep that in mind if you use access() for such checks.
posix_access
(PHP 5 >= 5.1.0)
posix_access — Determine accessibility of a file
說明
bool posix_access
( string
$file
[, int $mode = POSIX_F_OK
] )posix_access() checks the user's permission of a file.
參數
-
file -
The name of the file to be tested.
-
mode -
A mask consisting of one or more of
POSIX_F_OK,POSIX_R_OK,POSIX_W_OKandPOSIX_X_OK.POSIX_R_OK,POSIX_W_OKandPOSIX_X_OKrequest checking whether the file exists and has read, write and execute permissions, respectively.POSIX_F_OKjust requests checking for the existence of the file.
回傳值
如果成功則回傳 TRUE，失敗則回傳 FALSE。
範例
Example #1 posix_access() example
This example will check if the $file is readable and writable, otherwise will print an error message.
<?php
$file = 'some_file';
if (posix_access($file, POSIX_R_OK | POSIX_W_OK)) {
echo 'The file is readable and writable!';
} else {
$error = posix_get_last_error();
echo "Error $error: " . posix_strerror($error);
}
?>
註釋
Note: 當安全模式被啟用時，PHP 將檢查被操作的檔案或者目錄是否與正在執行的腳本有相同的 UID（擁有者）。
參見
- posix_get_last_error() - Retrieve the error number set by the last posix function that failed
- posix_strerror() - Retrieve the system error message associated with the given errno
add a note
User Contributed Notes 1 note
unixguy at earth dot com ¶
9 years ago
