backup mysql database by calling a batch file through php

I failed with the mysqldump method earlier. Now I'm trying to just call the batch file which will call the mysqldump. The php file which calls the 开发者_Go百科batch file, looks something like this:

<?php
shell_exec('c:\\abc.bat');

?>

And the batch file, which when I execute directly yields the 7kb sql file that I'm expecting:

mysqldump --opt -u root -ppassword onstor > c:\onstordb.sql

But when I use php to execute it, I get a 0 Kb file, I wonder why. I tried both shell_exec and exec. Is there something wrong with the parameters?

http://www.php.net/manual/en/function.exec.php#85930

It reads:

I was having trouble using the PHP exec command to execute any batch file. Executing other commands (i.e., "dir") works fine). But if I executed a batch file, I receieved no output from the exec command.

The server setup I have consists of Windows Server 2003 server running IIS6 and PHP 5.2.3. On this server, I have:

1. Granted execute permissions to the Internet User on c:\windows\system32\cmd.exe.
2. Granted Everyone->Full Control to the directory in which the batch file is written.
3. Granted Everyone->Full Control on the entire c:\cygwin\bin directory and its contents.
4. Granted the Internet User "log on as batch" permissions.
5. Specified the full path to each file being executed.
6. Tested these scripts running from the command line on the server and they work just fine.
7. Ensured that %systemroot%\system32 is in the system path.

It turns out that even with all of the above in place on the server, I had to specify the full path to cmd.exe in the exec call.

When I used the call:

$output = exec("c:\\windows\\system32\\cmd.exe /c $batchFileToRun");

then everything worked fine. In my situation, $batchFileToRun was the actual system path to the batch file (i.e., the result of a call to realpath()).