142345 - Wrong code fragments in mozilla/nsprbub/pr/src/md/uxshm.c

Status: RESOLVED FIXED

(NSPR :: NSPR, defect)

Description

[Vladimir Golitsin]

The file contains the following code fragment (routine _MD_OpenSharedMemory, 
lines 114-122):
        int osfd = open( shm->ipcname, (O_RDWR | O_CREAT), shm->mode );
        if ( -1 == osfd ) {
            _PR_MD_MAP_OPEN_ERROR( errno );
            PR_FREEIF( shm->ipcname );
            PR_DELETE( shm );
            return( NULL );
        } 
        if ( close(osfd == -1 )) {
            _PR_MD_MAP_CLOSE_ERROR( errno );
The line 
        if ( close(osfd == -1 )) {
is due to a obevious mistake...
The same is repeated in _MD_CloseSharedMemory, the line 247.
Even if the code is recently not used by Mozilla it worth to be
fixed anyway.

NOTE. I found the error just reviewing the code. It affects the paltforms
supporting shared memory in the System V way (e.g. Sun).

Comment 1

[Wan-Teh Chang]

Attachment: Proposed patch

Comment 2

[Wan-Teh Chang]

Thanks for the bug report.  You are right.  I checked in the
fix you suggested into the tip of NSPR.

With the original code, we would close the Unix file descriptor
0 (because osfd is not equal to -1).  close(0) would succeed in
most processes (fd 0 is the standard input) and return 0, so
the body of the if statement is not executed.  This is why we
have not noticed this bug.

Comment 3

[Wan-Teh Chang]

*** Bug 172910 has been marked as a duplicate of this bug. ***