An error occurred while uploading data in linux. tmp_name is empty.

Failed to upload files in linux environment tmp_name is empty phpinfo the following information is displayed: file_uploadsOnupload_max_filesize2Mupload_tmp_dir/Users/ririn/Sites/tmp then & nbs tmp_name is empty when the file fails to be uploaded in linux
Phpinfo displays the following information:
File_uploadsOn
Upload_max_filesize2M
Upload_tmp_dir/Users/ririn/Sites/tmp
Then I set the 777 permission for this directory chmod 777/Users/ririn/Sites/tmp. Is there anything else to set?
But I still cannot upload files.
First, the tmp directory does not contain any files.
Of course, $ tmp = $ _ FILES ['mypic '] ['tmp _ name'] is used in the background. this cannot be obtained either...

In win, the configuration in win is normal. the configuration here is the same as that in win. the selected file is only over 100 kB.

I still need to post my code, isn't it linux? what should I add?



$ Tmp = $ _ FILES ['mypic '] ['tmp _ name']; // empty
$ Name = $ _ FILES ['mypic '] ['name'];
$ Size = $ _ FILES ['mypic '] ['size'];
$ Arr = array (
'Tmp '=> $ tmp,
'Name' => $ name,
'Size' => $ size
);
Var_dump ($ arr );

?>
The last print is array (3) {["tmp"] => string (0) "" ["name"] => string (9) "scoot.png" ["size"] => int (0 )}
In Windows, the upload permission for Linux is completely normal and shared:
------ Solution --------------------
You can directly print_r ($ _ FILE) on the php page pointed to by form to test whether there is any result.
------ Solution --------------------
Var_dump ($ _ FILES );