Open Radar

 
28-Jan-2009 02:10 AM Joachim Bengtsson:
Summary:
Trying to read more than 4096 bytes in one go with NSFileHandle's readDataOfLength will lock up forever, never returning.

Steps to Reproduce:
1. Create a new Foundation tool.
2. Write the following in your impl file:
#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSFileHandle *fh = [[NSFileHandle alloc] initWithFileDescriptor:fileno(fopen("/dev/random", "r"))];
    
    NSLog(@"Reading 4096 bytes... This will succeed.");
    [fh readDataOfLength:4096];
    NSLog(@"Reading 4097 bytes... This will lock for infinity");
    [fh readDataOfLength:4097];
    NSLog(@"This will never be printed.");
    
    [fh closeFile];
    [fh release];

    [pool drain];
    return 0;
}

3. Compile and run

Expected Results:
4. See the output:
2009-01-28 10:55:06.164 NSFileHandleIsEvil[42953:10b] Reading 4096 bytes... This will succeed.
2009-01-28 10:55:06.229 NSFileHandleIsEvil[42953:10b] Reading 4097 bytes... This will lock for infinity
2009-01-28 10:55:06.230 NSFileHandleIsEvil[42953:10b] This will never be printed.

The Debugger has exited with status 0.

Actual Results:
2009-01-28 10:55:06.164 NSFileHandleIsEvil[42953:10b] Reading 4096 bytes... This will succeed.
2009-01-28 10:55:06.229 NSFileHandleIsEvil[42953:10b] Reading 4097 bytes... This will lock for infinity
< No more output, ever >

Regression:
Unknown

Notes:
This is a very serious bug. For example, the above program seems to try to read an infinite amount of data from /dev/random. This is so very wrong.

Blog entry on the subject: http://overooped.com/post/73721688/nsfilehandle-considered-harmful


'NSFileHandleIsEvil.m' and 'Vermillion.spx' were successfully uploaded

13-Jun-2009 01:46 AM Vanaja Pasumarthi :
We believe this issue has been addressed in Mac OS X SnowLeopard (Client), build 10A380.  Please verify with the build that you obtained at WWDC, and update this report with your results.

27-Jun-2009 07:46 AM Joachim Bengtsson:
This issue has been verified as resolved and can be closed.

Thanks!