[vorbis-dev] ogg123 doesn't destroy shm segment

[Christian Weisgerber]

Every time ogg123 -bXXX is run, it creates another shared memory
segment but fails to destroy it on exit.  Thus an increasing number
of shm segments keeps piling up and eat all the (often rather
limited amount of) available shared memory.

The patch below corrects this and also fixes the bizarre abuse of
stat() permission bits for shmget().

On systems that support it, I'd very much like to get rid of using
SYSVSHM altogether and instead use a shared memory mapping of
/dev/zero.  The code is very simple and I have it running on BSD,
but I still need to steal an autoconf fragment to test for availability
of this feature in a portable manner.  More on this later.

Index: ogg123/buffer.c
===================================================================
RCS file: /usr/local/cvsroot/vorbis-tools/ogg123/buffer.c,v
retrieving revision 1.3
diff -u -r1.3 buffer.c
--- ogg123/buffer.c	2001/01/30 10:42:48	1.3
+++ ogg123/buffer.c	2001/03/17 14:38:36
@@ -8,7 +8,6 @@
 #include <sys/types.h>
 #include <sys/ipc.h>
 #include <sys/shm.h>
-#include <sys/stat.h>
 #include <sys/time.h>
 #include <unistd.h> /* for fork and pipe*/
 #include <fcntl.h>
@@ -76,7 +75,7 @@
   /* Get the shared memory segment. */
   int shmid = shmget (IPC_PRIVATE,
                           sizeof(buf_t) + sizeof (chunk_t) * (size - 1),
-			  IPC_CREAT|S_IREAD|S_IWRITE);
+			  IPC_CREAT|SHM_R|SHM_W);
 
   if (shmid == -1)
     {
@@ -92,7 +91,10 @@
       perror ("shmat");
       exit (1);
     }
-  
+
+  /* Remove segment after last process detaches it or terminates. */
+  shmctl(shmid, IPC_RMID, 0);
+
   buffer_init (buf, size);
   
   /* Create a pipe for communication between the two processes. Unlike

-- 
Christian "naddy" Weisgerber                          naddy at mips.inka.de

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