Microsoft Removes 260-Character Path Length Limit In Windows 10 Redstone (softpedia.com)
An anonymous reader quotes a report from Softpedia: Windows 10 build 14352, a preview version of the upcoming Anniversary Update (also known as Redstone), comes with an eagerly awaited change that Microsoft hasn't yet announced publicly. The 260-character path length limit in Windows can be removed with the help of a new policy, thus allowing you to run operations with files regardless of their path or file name. While this new rule is not enabled by default, admins can turn it on by following these instructions. Launch the Registry Editor by clicking the Start menu and typing "regedit.exe," and then navigate to the following path: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy Objects\{48981759-12F2-42A6-A048-028B3973495F}Machine\System\CurrentControlSet\Policies. Look for an entry called "LongPathsEnabled," and if it does not exist, simply right-click Policies, select New DWORD (32-bit), name it "LongPathsEnabled" (without the quotes), enter value 1, and you're good to go. The description of the preview reads, "Enabling NTFS long paths will allow manifested win32 applications and Windows Store applications to access paths beyond the normal 260 char limit per node. Enabling this setting will cause the long paths to be accessible within the process." While the Windows 10 preview build 1452 has been made available last week, according to Windows Central, a Microsoft team member says that the company could released Windows 10 Mobile build 14352 for Insiders on Tuesday, May 31.
There's nothing simple about fucking around in the registry. Why can't Microsoft just do things correctly the first time?
I can replace my Linux machine!
“He’s not deformed, he’s just drunk!”
I no longer have to maintain a relatively flat file directory structure? My directories can finally go to... plaid?!
I want to be excited about Windows 10 but I can't. Please, please, please give me an official option to turn off telemetry like the Enterprise version has. I'm also interested in the Long-term Servicing Branch.
Thanks,
A home user and family IT guy.
While this might work for new applications and may work internally, there are a fair number of C++ applications out there that use the pre-defined MAX_PATH preprocessor define to allocate an array on the stack to receive a path. Such as:
TCHAR filePath[MAX_PATH];
GetSomething(hFile, filePath, sizeof(filePath)/sizeof(TCHAR));
This code is already compiled to a fixed size buffer to receive the path. Mostly because this is what was in all the Win32 examples and best practices guides. Fortunately, these functions still take a length of the buffer so I don't think we'll run into any buffer overrun issues, but they would just fail to work with the long paths until there is some type of API call to get the size of the buffer we need to allocate.
Microsoft managers train with the airlines.
The compatibility issue is likely exactly why it's limited to Win32 applications with a manifest and Metro apps.
Comment removed based on user account deletion
This isn't just something you can switch on without thought.
Windows' native programming has long had a "MAX_PATH" constant, which devs would use to create a char[MAX_PATH] to accept user input (i.e. from a save file dialog). If you suddenly start creating paths larger than this, you risk buffer overflows.
Even if your app is carefully written to avoid buffer overflows in this situation, it may simply refuse to read the file with a path too large. Devs have been able to break beyond MAX_PATH for a while by using UNC paths, but almost nobody uses them because you'll find random apps that won't know how to use a longer path.
I find it a bit weird that they haven't taken an approach similar to high DPI, where you can embed a manifest resource into your app that'll tell the OS it supports high DPI. While this would not solve random apps refusing to work with larger paths, this would at least prevent buffer overflows.
But no thanks ; not using OSes that have registries.
Slashdot, fix the reply notifications... You won't get away with it...
This is not an NTFS problem but an old API problem that programs should have stopped using years ago (decades, actually).
Programs like the NPM Nodejs package manager have had, until recently, horrifically long pathnames for no good reason. This fixes that for them.
Nearly any other program doesn't have this problem.
Good job, NPM developers, for forcing MSFT to update a very old API that you still insist on using.
Kriston
This will be a great improvement. I have Windows 10 running on my IoT garden GNAAomes and can't wait until they have this functionality.
I don't imagine there are many people who are just dying to have filenames longer than 260 characters.
For every problem, there is at least one solution that is simple, neat, and wrong.
We still use Netware here. No spying, no Windows 95-era path-length limits, No facebook integration, etc..., easy to back up.
Because as stated in another thread, MS/W devs do `char path[MAX_PATH];` So if MS removes the limit most programs will stack overflow.
Slashdot, fix the reply notifications... You won't get away with it...
I have to agree in this case. If you need more than 260, you are probably doing something stupid, and the few cases where it's not stupid are overshadowed by the vast majority that are.
Table-ized A.I.
The summary mentions that it will only be available to manifested applications, i.e. ones for which the developer has already indicated it can deal with longer paths. Given that protection, there is absolutely no need for additional protection via a registry key.
I was at a company which developed a large CRM application and I was the person who tarred up software updates to send to sites. A small part of the application was in Java, and the Java programmers were enamoured with class names which emphasized descriptiveness over brevity. We ended up with some files where path+filename exceeded 255 characters, and tar broke. My fix was to tell the programmers to shorten their damn file and directory names. (This was about 15 years ago, and it would have been Gnu tar. )
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
That's actually funny.
Whilst paths could theoretically be any length on UFS, there was (actually still is) a #define called PATH_MAX which practically every programmer used to allocate buffers to hold paths. According to Posix, the absolute largest this define can be is 256 (fortunately, Linux ignores this and goes for 4096).
I bet there is a lot of Unix code out there that breaks, possibly in subtle ways when paths exceed PATH_MAX characters.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
Prepend "\\?\" to the path to tell the standard API to ignore MAX_PATH. This is how Robocopy and many other tools work around the issue.
Area51 - We are watching...
Yeah, I was wondering if they only bought Minecraft so they could use their codename.
True. Node is literally the only time that I've run into this problem in my entire career. Maybe I've led a sheltered life, but still....
Perhaps in a weird situation you might want to protect a badly coded application from the longer path length?
Due to the design of the Windows API, almost all applications are 'badly coded' in this respect.
Yeah, whereas with other OSs, deleting random configuration data has no effect.
And allow us to use files called CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9.
:, ", |,?,* characters.
Or use of <, >,
Or the other strange arbitrary rules, e.g. spaces allowed in names but a filename must have something other than spaces in it. There are many others.
But Linux also should probably not limit file paths to 4096, I'd have thought that might start to be an issue for people using a lot of Unicode.
Have you ever run ProcessMonitor and performed some mundane action in windows explorer?
09F91102 no, 455FE104 nope, F190A1E8 uh-uh, 7A5F8A09 that's not it, C87294CE no. Ah! 452F6E403CDF10714E41DFAA257D313F.
Hmmm...I just checked IRIX 6.5.29, plus Solaris 10 and 11- it says 1024, but also defines POSIX_PATH_MAX to 255
I'm starting to think GNU is the problem with "GNU/Linux" these days.
Great!
Now if only I could resize a whole slew of windows....I know its new tech, and very hard to do, but pulling at the edges of a window SHOULD let you RESIZE IT...
hold on to your gravy grandpa!
Just the most relevant example, the path window itself in windows does NOT let you resize it, there are also several in visual studio which have huge lines in them, but nope, can't resize them, they are the perfect size!
No.
Because as stated in another thread, MS/W devs do `char path[MAX_PATH];` So if MS removes the limit most programs will stack overflow.
You may mean buffer overflow here.
The declaration you've quoted would be resolved at compile time, not run time. So if MAX_PATH was 260 at compile time and then run on a system where the runtime behavior allowed for longer paths, I could certainly see a buffer overflow condition happening. But the program will only ever allocated 260 bytes off the stack in that case, so stack usage would remain the same.
And I assume if MAX_PATH were _UI64_MAX (or whatever) at compile time, the compiler would complain.
The might stack overflow, depending on how they are written they also might do other things. I bet there is a fair amount of strncpy(foo, bar, MAX_PATH); out there as well. Which could lead to strings that are not null terminated but also don't overwrite, the result probably being some kind of crash when foo is read, the other possibility is truncation. A Only the first 260 bytes of path get copied the result is some later action is taken on the partial path. Maybe that fails, maybe that results in a new file, maybe something like a temp file is create but not deleted by a later clean up routine filling the disk who knows.
This could cause any all types of chaos.
Repeal the 17th Amendment TODAY! Also Please Read http://www.gnu.org/philosophy/right-to-read.html
Yeah, I can see whole city blocks of dev shops starting up and finding new ways stuff those files paths as long as possible. Eventually, all files will have had every scrap of data and metadata pulled out, base64 encoded or similar and stuffed into the pathname. A 4GB movie file would simply become a ~6GB pathname. Actual files would be unnecessary, just directories and their names, lovely long make Microsoft money names!
Linux and others could do that for decades. Nice to see that Microsoft is catching up and removes the remaining DOS limitations. I guess it is asking to much to have them backport this to Win7/8. In which build to they do away with drive letters? And when is NTFS replaced with a modern and performant file system?
It should be:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Policies -or-
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem
Credit goes to user foobar in the article's comment section.
'He who has to break a thing to find out what it is, has left the path of wisdom.' -- Gandalf to Saruman
I misread that as MSJW devs, and now I'm really hoping that doesn't become a thing.
Inheritance is the sincerest form of nepotism.
The idea is the guy assumes that no path will have a longer length than MAX_PATH. So for already compiled programs (before win10 option) the guy may `strcpy` into `path` any path given by the system with no much care. This would be indeed buffer overflow. But MAX_PATH may be given a much larger value by default in the new win10, in this case stack overflow... (and likely a warning by the compiler).
Slashdot, fix the reply notifications... You won't get away with it...
Undefined behavior, indeed.
Slashdot, fix the reply notifications... You won't get away with it...
It appears that in some industries workplace health and safety documentation policies are exactly that kind of stupid. Why I have no idea, but so many tedious artificial emergencies have cropped up from people losing access to their stuff due to insanely deep nesting with even more insane long filenames.
The really hilarious (after the things have been recovered) side of it is being able to write stuff with a long path but not being able to read it back later.
"I've got a meeting in five minutes and I've copied the files so deep that the sun doesn't shine on them" proves the wisdom of having the files on a fileserver under adult supervison of an OS that can actually get to them.
Good to see that problem is going to go away.
oh!
wait.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
They found the 8.3 file name format very confining. So they did a simple hack. They would construct the file/path name just as they would in unix. Then send it through a string processor that will insert a "\" after every 8th char and keep creating sub directories to get the file name they wanted! User will see humongous file names and path names.
Our company has been supporting 4K path names now, I remember setting MAXPATHLEN to be 1025 (remember to allocate space for the trailing null) back when joined the company decades ago.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I misread that as MSJW devs, and now I'm really hoping that doesn't become a thing.
Their code would never run successfully:
- They'd consider it every program's right to call abort(); without being criticized.
- They could only use peer-to-peer architectures, as master / slave is oppressive.
- All branching logic would initially be floating-point -based, as Boolean logic is exclusionary and thus a micro-aggression against LGBTQ culture. However, it would later be decided that forcing branching logic was inherently judgmental, and thus all program instructions must have an equal chance to execute every processor clock tick.
The one upside is that their code would be meticulously designed to avoid race conditions. Sadly, it would also be subject to nearly constant deadlock.
Keep laughing, how many system critical variables is systemd in charge of now?
Only the State obtains its revenue by coercion. - Murray Rothbard
We've had to use robocopy et al to delete too-long-named directory trees for how many years now?
I normally run into the character path length limit when performing a copy of user files within Explorer.
Users will often type descriptive names for files but they don't have knowledge of character or path limits.
It seems as though this has been sort of "half assed" implantation for a long time in Windows where some programs (including MS's own stuff) use old API's which enforce the limitation and other programs use newer APIs (or just do stuff directly) and work around the limit.
This created many cases in which these files and paths can exist on the file system and can be accessed by some applications but not others.
It's not a life altering change, but I welcome it. I am hoping this is the start of some long standing bug fixes.
My eyes reflect the stars and a smile lights up my face.
256 is th minimum allowed value to be POSIX compliant. Think real hard I bet you can guess how that value ended up there. I don't think there's ever been a *nix below 1024.
Does anyone remember back in the day when you could BSOD Windows 9x machines by calling CON, LPT1, COM1 in an IMG HTML tag?
<img src=LPT1>
Long names may be great for making very descriptive names for your files and folders, but they also increase the time it takes to find stuff. When you want to find all of your .JPG photo files by traversing your file system looking for any files with that extension; then be prepared to wait a long time if you have a lot of files and even longer if your names are really long. It takes many more processor instructions to process each string looking for patterns or file extensions. If you only have a few thousand files, then you might not notice it, but put 10 million (or 100 million) files in one of your volumes and you certainly will.
PATH_MAX is the length of path gauranteed to work on this OS (and can be different for each OS).
POSIX_ PATH_MAX is the lowest value of PATH_MAX allowed on other POSIX systems, which could matter for network communication etc. It's 256.
Why does this fact need a whole article on slashdot. Max path length has been 4096 on Linux for ages.
Some languages smush together a bunch of adjectives & tack on a noun: presto--unambiguous file/folder names! If translated, you still get a paragraph-long path, but now with spaces.
subst and robocopy are your friends!
"Reality is that which, when you stop believing in it, doesn't go away." - Philip K. Dick
The problem is not going away, just changing. Just because the system allows huge (deep) paths and file-names doesn't mean people will know how to use them. It may confuse them enough that they cannot find or manage their files, and complain to the help desk.
It's like building a pickup truck that can accept giant tires. Fools will put 40-foot tires on their trucks to be big-shots or because somebody told them it's good, and crash into regular folks.
Table-ized A.I.
Including the bash shell and now addressing the 260 character file path limit? Windows just got waaaaaay less annoying to use for developers employing package managers like Bower and NPM.
Not sure if it will bring defectors back into the Windows camp but it sure will be nice for enterprise developers that are forced to use Windows. Then again, enterprise won't standardize on Windows 10 for another five years or so.
Have you actually read that POSIX doc?
256 is the smallest acceptable value for PATH_MAX, not the largest.
PATH_MAX >= _POSIX_PATH_MAX >= 256
Most interfaces than return paths (eg. readlink(2), getcwd(3)) take a buffer and a length as arguments, and return an error if the buffer is too short, so most of the time you can allocate the buffers dynamically and completely ignore any system specific limits.
This has always been possible in Windows NT, but the shell kept limits in place for backward compatibility. Expect older application to break in deep directories or with any path that otherwise exceeds MAX_PATH characters.
command.com (being a DOS shell out, operating in 16-bit DOS mode) had the 256 byte limit, but cmd.exe (being a proper Win32 API oriented command-line shell) has had the ability to use the Unicode (\\?\) paths since at least Win2k, if not before that. The tools available under cmd.exe nearly all support the Unicode filename format and have for a long time. That was one of the big draws for using cmd.exe over command.com - less restrictions in use.
Truth is like the sun. You can shut it out for a time, but it ain't goin' away. - Elvis Presley (source: imdb.com)
It's not just third-party code. Win32 has APIs like this - note the MAX_PATH sized member of the struct.
Which "old API" is that that programs "should have stopped using years ago", exactly?
As for npm, it can handle long path names just fine (it uses \\?\ paths to achieve that). The problem, rather, is that most other things in Windows land couldn't handle those paths. So npm would create a directory tree that Windows Explorer couldn't delete, for example.
True, a technical problem has gone away but stupidity can still remain.
Those directory names I was writing about have punctuation in them! Commas, semicolons, everything apart from asterisks. You can get to them nested deep on a *nix filesystem but it's a pain.
People blame quality assurance systems but the initial guidelines don't mandate such stupid implementations - it's just someone doing something really stupid and others copying them in between Facebook employee stalking and farmville or whatever the latest game on there is.
I suggest you to use Long Path Tool Program it will solve the problems of path too long.