postgres.git / summary / log / commit / refs

commit    8201b60565b8da465e75da4e4c6d2f01bf976a43
Author:   Thomas Munro <tmunro@postgresql.org>
Date:     Thu Aug 12 22:38:22 2021 +0000

    Make EXEC_BACKEND more convenient on macOS.
    
    It's hard to disable ASLR on current macOS releases, for testing with
    -DEXEC_BACKEND.  You could already set the environment variable
    PG_SHMEM_ADDR to something not likely to collide with mappings created
    earlier in process startup.  Let's also provide a default value that
    works on current releases and architectures, for developer convenience.
    
    As noted in the pre-existing comment, this is a horrible hack, but
    -DEXEC_BACKEND is only used by Unix-based PostgreSQL developers for
    testing some otherwise Windows-only code paths, so it seems excusable.
    
    Back-patch to all supported branches.
    
    Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
    Discussion: https://postgr.es/m/20210806032944.m4tz7j2w47mant26%40alap3.anarazel.de


 src/backend/port/sysv_shmem.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c
index 0cc83ffc16a..9de96edf6ad 100644
--- a/src/backend/port/sysv_shmem.c
+++ b/src/backend/port/sysv_shmem.c
@@ -143,6 +143,16 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, Size size)
 
 		if (pg_shmem_addr)
 			requestedAddress = (void *) strtoul(pg_shmem_addr, NULL, 0);
+		else
+		{
+#if defined(__darwin__) && SIZEOF_VOID_P == 8
+			/*
+			 * Provide a default value that is believed to avoid problems with
+			 * ASLR on the current macOS release.
+			 */
+			requestedAddress = (void *) 0x80000000000;
+#endif
+		}
 	}
 #endif
 


[parent: 886531f3f403]