Mark shared libraries private clean pages as non-writable on FreeBSD.

This is how persmissions are with Linux, and later simgrid identifies
mappings based on path and permissions, so the less restistance path
is to present things more linux-like.

diff --git a/src/xbt/memory_map.cpp b/src/xbt/memory_map.cpp
index fed4b2c..e55ae03 100644 (file)
--- a/src/xbt/memory_map.cpp
+++ b/src/xbt/memory_map.cpp
@@ -209,15 +209,13 @@ XBT_PRIVATE std::vector<VmMap> get_memory_map(pid_t pid)
     memreg.end_addr = vmentries[i].kve_end;
 
     /* Permissions */
-    memreg.prot = 0;
+    memreg.prot = PROT_NONE;
     if (vmentries[i].kve_protection & KVME_PROT_READ)
       memreg.prot |= PROT_READ;
     if (vmentries[i].kve_protection & KVME_PROT_WRITE)
       memreg.prot |= PROT_WRITE;
     if (vmentries[i].kve_protection & KVME_PROT_EXEC)
       memreg.prot |= PROT_EXEC;
-    if (memreg.prot == 0)
-      memreg.prot |= PROT_NONE;
 
     /* Private (copy-on-write) or shared? */
     if (vmentries[i].kve_flags & KVME_FLAG_COW)
@@ -250,6 +248,16 @@ XBT_PRIVATE std::vector<VmMap> get_memory_map(pid_t pid)
         && vmentries[i].kve_flags & KVME_FLAG_GROWS_DOWN)
       memreg.pathname = "[stack]";
 
+    /*
+     * One last dirty modification: remove write permission from shared
+     * libraries private clean pages. This is necessary because simgrid
+     * later identifies mappings based on the permissions that are expected
+     * when running the Linux kernel.
+     */
+    if (vmentries[i].kve_type == KVME_TYPE_VNODE
+        && ! (vmentries[i].kve_flags & KVME_FLAG_NEEDS_COPY))
+      memreg.prot &= ~PROT_WRITE;
+
     ret.push_back(std::move(memreg));
   }
   procstat_freevmmap(prstat, vmentries);