Cfrtjryk

Here's what I tried to do myself:

$ type 1.sh

#!/bin/bash -eu

php -r 'var_dump(file_get_contents($_SERVER["argv"][1]));' -- <(echo 1)

$ ./1.sh

PHP Warning:  file_get_contents(/dev/fd/63): failed to open stream: No such file or directory in Command line code on line 1



Warning: file_get_contents(/dev/fd/63): failed to open stream: No such file or directory in Command line code on line 1

bool(false)

I tested it on Debian 6 (php-5.4.14, bash-4.1.5) and Arch Linux (php-5.4.12, bash-4.2.42).

UPD

$ strace -f -e trace=file php -r 'var_dump(file_get_contents($_SERVER["argv"][1]));' -- <(echo 1)

...

open("/usr/lib/php5/20100525/mongo.so", O_RDONLY) = 3

lstat("/dev/fd/63", {st_mode=S_IFLNK|0500, st_size=64, ...}) = 0

readlink("/dev/fd/63", "pipe:[405116]"..., 4096) = 13

lstat("/dev/fd/pipe:[405116]", 0x7fff5ea44850) = -1 ENOENT (No such file or directory)

lstat("/dev/fd", {st_mode=S_IFLNK|0777, st_size=13, ...}) = 0

readlink("/dev/fd", "/proc/self/fd"..., 4096) = 13

lstat("/proc/self/fd", {st_mode=S_IFDIR|0500, st_size=0, ...}) = 0

lstat("/proc/self", {st_mode=S_IFLNK|0777, st_size=64, ...}) = 0

readlink("/proc/self", "31536"..., 4096) = 5

lstat("/proc/31536", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0

lstat("/proc", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0

open("/proc/31536/fd/pipe:[405116]", O_RDONLY) = -1 ENOENT (No such file or directory)

PHP Warning:  file_get_contents(/dev/fd/63): failed to open stream: No such file or directory in Command line code on line 1



Warning: file_get_contents(/dev/fd/63): failed to open stream: No such file or directory in Command line code on line 1

bool(false)



$ strace -f -e trace=file php <(echo 12)

...

open("/usr/lib/php5/20100525/mongo.so", O_RDONLY) = 3

open("/dev/fd/63", O_RDONLY)            = 3

lstat("/dev/fd/63", {st_mode=S_IFLNK|0500, st_size=64, ...}) = 0

readlink("/dev/fd/63", "pipe:[413359]", 4096) = 13

lstat("/dev/fd/pipe:[413359]", 0x7fffa69c3c00) = -1 ENOENT (No such file or directory)

lstat("/dev/fd/63", {st_mode=S_IFLNK|0500, st_size=64, ...}) = 0

readlink("/dev/fd/63", "pipe:[413359]", 4096) = 13

lstat("/dev/fd/pipe:[413359]", 0x7fffa69c19b0) = -1 ENOENT (No such file or directory)

lstat("/dev/fd", {st_mode=S_IFLNK|0777, st_size=13, ...}) = 0

readlink("/dev/fd", "/proc/self/fd"..., 4096) = 13

lstat("/proc/self/fd", {st_mode=S_IFDIR|0500, st_size=0, ...}) = 0

lstat("/proc/self", {st_mode=S_IFLNK|0777, st_size=64, ...}) = 0

readlink("/proc/self", "32214"..., 4096) = 5

lstat("/proc/32214", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0

lstat("/proc", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0

2

The problem is you want php to read input from a file descriptor, but you force it to read like regular file.

First, try this:

$ echo <(ls)

/dev/fd/63

then you can process ls output by reading /dev/fd/63. The process substitution will return the file descriptor, which is use by other command to reading its output.

In your case, you use $_SERVER["argv"][1], meaning that php will interpreter like this:

file_get_contents(/dev/fd/63)

From php manual, you can see protorype of file_get_contents function:

string file_get_contents ( string $filename [, bool $use_include_path =

false [, resource $context [, int $offset = -1 [, int $maxlen ]]]] )

Ops, php will consider /dev/fd/63 as normal file here, but it's really a file descriptor.

To access file descriptor, you must use php://fd, php://fd/63 will access content of file descriptor 63:

$ php -r 'var_dump(file_get_contents("php://".substr($_SERVER["argv"][1],-5)));' -- <(echo test.txt)

string(9) "test.txt

"

You can see, now php can process content in /dev/fd/63. But our purpose is reading content of file, which is provide via process substitution (In my example, it's test.txt). I don't know much about php, so I add another file_get_contents:

$ php -r 'var_dump(file_get_contents(file_get_contents("php://".substr($_SERVER["argv"][1],-5))));' -- <(echo -n test.txt)

string(13) "Hello world!

"

I use echo -n to remove newline from echo ouput, otherwise, php will see the ouput "test.txtn".

Note

For more information about accessing file descriptor in php, you can see here.

This is the problem:

readlink("/dev/fd/63", "pipe:[405116]"..., 4096) = 13

lstat("/dev/fd/pipe:[405116]", 0x7fff5ea44850) = -1 ENOENT

Without any good reason (IMHO) php tries to get the real name of the link target. Unfortunately the link target is not part of the file system thus the try to access that name fails and causes this error. The symlink can only be opened as such. I consider this a bug in php. You could use a FIFO instead:

mkfifo /my/fifo; output_cmd >/my/fifo & php -r ... /my/fifo

Here's what I ended up using...

php -r "var_dump(file_get_contents('php://stdin'));" < <(echo this is a win)

If you're trying to do other stuff with stdin this obviously won't work for you, and this is no different from

php -r "var_dump(stream_get_contents(STDIN));" < <(echo this is a win)

which leads me to wonder what it is you were actually trying to do, and why are you stuck on file_get_contents? :)

Reference - http://php.net/manual/en/wrappers.php.php

This is an old question but I just figured out the answer so I thought I'd share. Maybe it will help someone.

You can use the php:// stream wrapper to open the file descriptor instead:

 $fd = $argv[1];

 $handle = fopen(str_replace('/dev/','php://',$fd)); 

So instead of opening the /dev/fd/[nn] file descriptor provided by the OS. You'll be opening php://fd/[nn] which will work. I'm not sure why opening the file descriptor fails on some systems but not others.

This was an old bug and was supposed to have been fixed.