[AD] Mac OS X: file_exists bus error

[Jay Bernardo <allegrolist@xxxxxxxxxx>]

In the latest revision of the 4.2 branch of Allegro code (5817 at time of writing) there is a problem with the file_exists function. Apparently, if the specific file you're looking for does not exist, nothing bad happens (it operates as intended). However, if it does exist, we get a bus error. I'm going to paste in the test program I wrote to ensure that it's broken in general (and not just in my project) as well as a backtrace after running it through GDB and making it produce the bus error as this information is probably useful.

Some notes about the code: currently it just looks for the directory "hello." I also tried nesting directories in the form of "hello/foo." If foo did not exist, the program worked fine. If foo did exist, but was not a directory, the program ran fine. If foo existed and was a directory, we get the bus error. The same symptoms happen when searching for normal files using the attribute of "~FA_DIREC" (anything but a directory)

Running PPC Mac OS X 10.4.6. I did a fresh update/depend/make/install/etc. If you need any more information, let me know

-Jay

CODE:

---

#include <allegro.h>

int main()

{

        allegro_init();

        if(file_exists("hello", FA_DIREC, NULL) == 0)

        {

                fprintf(stderr, "The directory doesn't exist!\n");

        }

        else

        {

                printf("Directory found!\n");

        }

        return 0;

}

END_OF_MAIN()

---

GDB Backtrace:

---

(gdb) file a.out

Reading symbols for shared libraries .... done

Reading symbols from /Users/jay/Desktop/test/a.out...done.

(gdb) run

Starting program: /Users/jay/Desktop/test/a.out

Reading symbols for shared libraries ................................................................................ done

Program received signal EXC_BAD_ACCESS, Could not access memory.

Reason: KERN_PROTECTION_FAILURE at address: 0x00000020

[Switching to process 3641 thread 0x3503]

0x900017dc in pthread_mutex_lock ()

(gdb) backtrace

#0  0x900017dc in pthread_mutex_lock ()

#1  0x9001b258 in closedir ()

#2  0x300cc0ac in al_findclose ()

#3  0x30027fb4 in file_exists ()

#4  0x00002a70 in _mangled_main ()

#5  0x00002f8c in call_user_main ()

#6  0x00002fcc in +[AllegroAppDelegate app_main:] ()

#7  0x92976194 in forkThreadForFunction ()

#8  0x9002ba68 in _pthread_body ()