* mmalloc.h (struct mdesc): Add FIXME comments to point out the

	need to save some data on a per-process basis for mapped regions
	that are shared.
	* attach.c (reuse):  Update the morecore field for reused mapped
	regions to be correct for the current process.

1 files changed, 14 insertions, 6 deletions

diff --git a/mmalloc/attach.c b/mmalloc/attach.c
index 44fff4f..fcfb772 100644
--- a/mmalloc/attach.c
+++ b/mmalloc/attach.c
@@ -21,12 +21,16 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <string.h>
 #include "mmalloc.h"
 
 #ifndef SEEK_SET
 #define SEEK_SET 0
 #endif
 
+
+#if defined(HAVE_MMAP)
+
 /* Forward declarations/prototypes for local functions */
 
 static struct mdesc *reuse PARAMS ((int));
@@ -62,9 +66,6 @@ static struct mdesc *reuse PARAMS ((int));
 
    On failure returns NULL. */
 
-
-#if defined(HAVE_MMAP)
-
 PTR
 mmalloc_attach (fd, baseaddr)
   int fd;
@@ -100,8 +101,8 @@ mmalloc_attach (fd, baseaddr)
      then initialize the fields that we know values for. */
 
   mdp = &mtemp;
-  memset ((char *) mdp, 0, sizeof (mtemp));
-  strncpy (mdp -> magic, MMALLOC_MAGIC, MMALLOC_MAGIC_SIZE);
+  (void) memset ((char *) mdp, 0, sizeof (mtemp));
+  (void) strncpy (mdp -> magic, MMALLOC_MAGIC, MMALLOC_MAGIC_SIZE);
   mdp -> headersize = sizeof (mtemp);
   mdp -> version = MMALLOC_VERSION;
   mdp -> morecore = __mmalloc_mmap_morecore;
@@ -130,7 +131,7 @@ mmalloc_attach (fd, baseaddr)
 
   if ((mbase = mdp -> morecore (mdp, sizeof (mtemp))) != NULL)
     {
-      memcpy (mbase, mdp, sizeof (mtemp));
+      (void) memcpy (mbase, mdp, sizeof (mtemp));
       mdp = (struct mdesc *) mbase;
     }
   else
@@ -155,6 +156,11 @@ mmalloc_attach (fd, baseaddr)
    after we've switched over to using the mapped in malloc descriptor 
    rather than the temporary one on the stack.
 
+   Once we've switched over to using the mapped in malloc descriptor, we
+   have to update the pointer to the morecore function, since it almost
+   certainly will be at a different address if the process reusing the
+   mapped region is from a different executable.
+
    Also note that if the heap being remapped previously used the mmcheck()
    routines, we need to update the hooks since their target functions
    will have certainly moved if the executable has changed in any way.
@@ -181,6 +187,7 @@ reuse (fd)
 	{
 	  mdp = (struct mdesc *) mtemp.base;
 	  mdp -> fd = fd;
+	  mdp -> morecore = __mmalloc_mmap_morecore;
 	  if (mdp -> mfree_hook != NULL)
 	    {
 	      (void) mmcheck ((PTR) mdp, (void (*) PARAMS ((void))) NULL);
@@ -196,6 +203,7 @@ reuse (fd)
    to link to, but trying to initialize access to an mmap'd managed region
    always fails. */
 
+/* ARGSUSED */
 PTR
 mmalloc_attach (fd, baseaddr)
   int fd;