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passthru

(PHP 4, PHP 5, PHP 7)

passthru — 执行外部程序并且显示原始输出

说明

void passthru ( string $command [, int &$return_var ] )

同 exec() 函数类似， passthru() 函数也是用来执行外部命令（command）的。当所执行的 Unix 命令输出二进制数据，并且需要直接传送到浏览器的时候，需要用此函数来替代 exec() 或 system() 函数。常用来执行诸如 pbmplus 之类的可以直接输出图像流的命令。通过设置 Content-type 为 image/gif，然后调用 pbmplus 程序输出 gif 文件，就可以从 PHP 脚本中直接输出图像到浏览器。

参数

command: 要执行的命令。
return_var: 如果提供 return_var 参数， Unix 命令的返回状态会被记录到此参数。

返回值

没有返回值。

注释

Warning

当用户提供的数据传入此函数，使用 escapeshellarg() 或 escapeshellcmd() 来确保用户欺骗系统从而执行任意命令。

Note:

如何程序使用此函数启动，为了能保持在后台运行，此程序必须将输出重定向到文件或其它输出流。否则会导致 PHP 挂起，直至程序执行结束。

Note: 安全模式启用时，可仅可用 safe_mode_exec_dir 执行文件。实际上，现在不允许在到可执行的路径中存在 .. 组件。

Warning

安全模式启用时，命令字符串会被 escapeshellcmd() 转换。因此，echo y | echo x 会变成 echo y \| echo x。

参见

exec() - 执行一个外部程序
system() - 执行外部程序，并且显示输出
popen() - 打开进程文件指针
escapeshellcmd() - shell 元字符转义
执行运算符

用户评论:

[#1] myselfasunder at gmail dot com dot dfvuks [2010-11-29 13:00:13]

PHP's program-execution commands fail miserably when it comes to STDERR, and the proc_open() command doesn't work all that consistently in non-blocking mode under Windows.

This command, although useful, is no different. To form a mechanism that will see/capture both STDOUT and STDERR output, pipe the command to the 'tee' command (which can be found for Windows), and wrap the whole thing in output buffering.

Dustin Oprea

[#2] Chroot [2008-07-29 09:48:57]

If you have chrooted apache and php, you will also want to put /bin/sh into the chrooted environment. Otherwise, the exec() or passthru() will not function properly, and will produce error code 127, file not found.

[#3] jo at durchholz dot org [2007-11-22 12:17:54]

Note to Paul Giblock: the command *is* run through the shell.
You can verify this on any Linux system with

<?php passthru ('echo $PATH'); ?>

You'll get the content of the PATH environment variable, not the string $PATH.

[#4] Paul Giblock [2007-05-18 11:30:04]

Stuart:

The pasthru function does not execute the program through the shell. What this mean, among other things, is that your PATH variable is never set. Therefore, you have to use full paths on everything.

I believe system() will run your program underneith a shell. This allow the program to run in a 'normal' environment.

-Paul

[#5] nuker at list dot ru [2006-01-03 05:51:52]

I wrote function, that gets proxy server value from the Internet Explorer (from
registry). It was tested in Windows XP Pro

(Sorry for my English)

<?php function getProxyFromIE() { exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft". "\Windows\CurrentVersion\Internet Settings\" /v ProxyEnable", $proxyenable,$proxyenable_status); exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft". "\Windows\CurrentVersion\Internet Settings\" /v ProxyServer", $proxyserver); if($proxyenable_status!=0) return false; #Can't access the registry! Very very bad... else { $enabled=substr($proxyenable[4],-1,1); if($enabled==0) return false; else { $proxy=ereg_replace("^[ \t]{1,10}ProxyServer\tREG_SZ[ \t]{1,20}","", $proxyserver[4]); if(ereg("[\=\;]",$proxy)) { $proxy=explode(";",$proxy); foreach($proxy as $i => $v) { if(ereg("http",$v)) { $proxy=str_replace("http=","",$v); break; } } if(@!ereg("^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\:". "[0-9]{1,5}$",$proxy)) return false; else return $proxy; } else return $proxy; } } } ?>
Note, that this function returns FALSE if proxy is disabled in Internet
Explorer. This function returns ONLY HTTP proxy server.

Usage:
<?php $proxy=getProxyFromIE(); if(!$proxy) echo "Can't get proxy!"; else echo $proxy; ?>

[#6] Stuart Eve [2005-12-08 11:24:35]

I dunno if anyone else might find this useful, but when I was trying to use the passthru() command on Suse9.3 I was having no success with the command:

$command = 'gdal_translate blahahahaha';

passthru($command);

It only worked once I put:

$command = '/usr/bin/local/gdal_translate blalalala';

passthru($command);

[#7] vijayramanan at rediffmail dot com [2005-10-13 03:09:58]

I had an issue when i used exec

I think we were echoing information on the test.php script.
for eg: when we tried

exec(php test.php,$array,$error);

the return was 127 and the code was failing.

checking the note on this page gave us a hint to use passthru instead.
The only thing to note is that you need to provide the fuull path.

now our command became

passthru(/bin/php /pathtotest/test.php,$array,$error);

this works.

yipeee!!!!!

[#8] stuartc1 at NOSPAM dot hotmail dot com [2005-08-09 07:52:56]

Thought it might beuseful to note the passthru seems to supress error messages whilst being run in Dos on Windows (test on NT).

To show FULL raw output including errors, use system().

[#9] igor at bboy dot ru [2005-06-23 13:33:35]

If you are using passthru() to download files (for dynamically generated content or something outside webserver root) using similar code:

header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"myfile.zip\"");
header("Content-Length: 11111");
passthru("cat myfile.zip",$err);

and your download goes fine, but subsequent downloads / link clicks are screwed up, with headers and binary data being all over the website, try putting

exit();

after the passthrough. This will exit the script after the download is done and will not interfere with any future actions.

[#10] sarel dot w at envent dot co dot za [2005-03-08 23:33:55]

Zak Estrada
14-Dec-2004 11:21
Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).

Remember, you'll also get this error if your file does not have executable permission.

[#11] puppy at cyberpuppy dot org [2005-03-02 14:50:50]

Regarding swbrown's comment...you need to use an output buffer if you don't want the data displayed.

For example:
ob_start();
passthru("<i>command</i>");
$var = ob_get_contents();
ob_end_clean(); //Use this instead of ob_flush()

This gets all the output from the command, and exits without sending any data to stdout.

[#12] Zak Estrada [2004-12-14 08:21:39]

Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).

[#13] php @ richud dot com [2004-05-27 08:30:31]

Regarding kpierre's post, be mindful that if you shell script errors, you will find the error output from it in the base error_log file (not virtualhost error_log) in apache.

[#14] jcr at marvel-databadge dot com [2003-09-04 11:23:30]

With apache 2.x on RH9 passthru() writes 1 byte at a time. Apache 2.x buffers and chunk encodes the output for you - but the chunked encoding devides the output in chunks of 1 byte each...thus several bytes of overhead per byte. I guess that buffering behaviour is by design - but caused problems for me with IE adobe acrobot 5 plugin. The plugin doesn't like like it if you send it a stream of 1 byte chunks - it tells you your file is not a pdf or gives a blank screen. Using output buffering (ob_start / ob_endflush) gives reasonable size chunks and the plugin works OK.

[#15] swbrown at ucsd dot edu [2003-06-03 20:41:27]

passthru() seems absolutely determined to buffer output no matter what you do, even with ob_implicit_flush(). The solution seems to be to use popen() instead.

[#16] kpierre at fit dot edu [2002-01-30 07:35:54]

The documention does not mention that passthru() will only display standard output and not standard error.

If you are running a script you can pipe the STDERR to STDOUT by doing

exec 2>&1

Eg. the script below will actually print something with the passthru() function...

#!/bin/sh
exec 2>&1
ulimit -t 60
cat nosuchfile.txt

[#17] andreas dot hochsteger at oeamtc dot at [2001-10-03 07:51:30]

If you sometimes get no output from passthru() use system() instead. This solved this problem for me (php 4.0.5 on Tru64 Unix compiled with gcc).

[#18] sidney at jigsaw dot nl [2001-06-20 17:25:17]

PJ's ulimit example is nice; however, if you include multiple commands in the script after the ulimit command, each gets its own, seperate 60 second time slot!<br>

Furthermore, these sixty seconds are *CPU* time. Most programs hang for other reasons than CPU hogging (for example, waiting for a database connection) so for most purposes the number 60 is rather too high.<br>

Try "ulimit -t 1" first, which will give you about 10^9 cycles on modern hardware -- quite enough to get a lot of work done!

[#19] PJ at piggei dot com [2001-02-14 17:06:20]

About the problem of zombies, you may call a bash script like this:

--------------------------
#! /bin/bash
ulimit -t 60

<your command here>
--------------------------