[patch] Add check for Emutramp

cffi_proc_exec.patch (text/plain), 1.93 KB, created by Magnus Granberg on 2015-01-02 12:37:15 UTC

--- a/c/malloc_closure.h	2014-04-30 11:16:17.000000000 +0200
+++ b/c/malloc_closure.h	2014-12-31 22:27:45.269814143 +0100
@@ -14,6 +14,43 @@
 # endif
 #endif
 
+/* On PaX enable kernels that have MPROTECT enable we can't use PROT_EXEC. */
+#ifndef MS_WIN32
+#include <stdlib.h>
+
+static int emutramp_enabled = -1;
+
+static int
+emutramp_enabled_check (void)
+{
+    char *buf = NULL;
+    size_t len = 0;
+    FILE *f;
+    int ret;
+    f = fopen ("/proc/self/status", "r");
+    if (f == NULL)
+        return 0;
+    ret = 0;
+
+    while (getline (&buf, &len, f) != -1)
+        if (!strncmp (buf, "PaX:", 4))
+            {
+                char emutramp;
+                if (sscanf (buf, "%*s %*c%c", &emutramp) == 1)
+                    ret = (emutramp == 'E');
+                break;
+            }
+    free (buf);
+    fclose (f);
+    return ret;
+}
+
+#define is_emutramp_enabled() (emutramp_enabled >= 0 ? emutramp_enabled \
+        : (emutramp_enabled = emutramp_enabled_check ()))
+#else
+#define is_emutramp_enabled() 0
+#endif /* FFI_MMAP_EXEC_EMUTRAMP_PAX */
+
 /* 'allocate_num_pages' is dynamically adjusted starting from one
    page.  It grows by a factor of PAGE_ALLOCATION_GROWTH_RATE.  This is
    meant to handle both the common case of not needing a lot of pages,
@@ -77,7 +114,15 @@ static void more_core(void)
     if (item == NULL)
         return;
 #else
-    item = (union mmaped_block *)mmap(NULL,
+    if (is_emutramp_enabled ())
+        item = (union mmaped_block *)mmap(NULL,
+                        allocate_num_pages * _pagesize,
+                        PROT_READ | PROT_WRITE | ~PROT_EXEC,
+                        MAP_PRIVATE | MAP_ANONYMOUS,
+                        -1,
+                        0);
+    else
+        item = (union mmaped_block *)mmap(NULL,
                         allocate_num_pages * _pagesize,
                         PROT_READ | PROT_WRITE | PROT_EXEC,
                         MAP_PRIVATE | MAP_ANONYMOUS,