0.9.4.71:

[sbcl.git] / src / runtime / linux-os.c

diff --git a/src/runtime/linux-os.c b/src/runtime/linux-os.c
index 222f0af..6724d15 100644 (file)
--- a/src/runtime/linux-os.c
+++ b/src/runtime/linux-os.c
@@ -52,6 +52,10 @@
 #include "gencgc-internal.h"
 #endif
 
+#ifdef LISP_FEATURE_LINUX
+#include <sys/personality.h>
+#endif
+
 size_t os_vm_page_size;
 
 #ifdef LISP_FEATURE_SB_THREAD
@@ -91,8 +95,23 @@ futex_wake(int *lock_word, int n)
 int linux_sparc_siginfo_bug = 0;
 int linux_no_threads_p = 0;
 
+#ifdef LISP_FEATURE_SB_THREAD
+int isnptl (void)
+{
+  size_t n = confstr (_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
+  if (n > 0)
+    {
+      char *buf = alloca (n);
+      confstr (_CS_GNU_LIBPTHREAD_VERSION, buf, n);
+      if (strstr (buf, "NPTL"))
+        return 1;
+    }
+  return 0;
+}
+#endif
+
 void
-os_init(void)
+os_init(char *argv[], char *envp[])
 {
     /* Conduct various version checks: do we have enough mmap(), is
      * this a sparc running 2.2, can we do threads? */
@@ -120,11 +139,50 @@ os_init(void)
     }
 #ifdef LISP_FEATURE_SB_THREAD
     futex_wait(futex,-1);
-    if(errno==ENOSYS)  linux_no_threads_p = 1;
-    if(linux_no_threads_p)
-        fprintf(stderr,"Linux with NPTL support (e.g. kernel 2.6 or newer) required for \nthread-enabled SBCL.  Disabling thread support.\n\n");
+    if(errno==ENOSYS) {
+       lose("This version of sbcl is compiled with threading support, but your kernel is too old to support this.\n\
+Please use a more recent kernel or a version of sbcl without threading support.\n");
+    }
+    if(! isnptl()) {
+       lose("This version of sbcl only works correctly with the NPTL threading library. Please use a newer glibc, older sbcl or stop using LD_ASSUME_KERNEL");
+    }
 #endif
     os_vm_page_size = getpagesize();
+
+    /* KLUDGE: Disable memory randomization on new Linux kernels
+     * by setting a personality flag and re-executing. (We need
+     * to re-execute, since the memory maps that can conflict with
+     * the SBCL spaces have already been done at this point).
+     */
+#if defined(LISP_FEATURE_X86)
+    if ((major_version == 2 && minor_version >= 6)
+        || major_version >= 3)
+     {
+       long pers = personality(-1);
+       /* 0x40000 aka. ADDR_NO_RANDOMIZE */
+       if (!(pers & 0x40000)) {
+          if (personality(pers | 0x40000) != -1) {
+              /* Use /proc/self/exe instead of trying to figure out the
+               * executable path from PATH and argv[0], since that's
+               * unreliable. We follow the symlink instead of executing
+               * the file directly to avoid top from displaying the
+               * name of the process as "exe".
+               */
+              char runtime[PATH_MAX+1];
+              int i = readlink("/proc/self/exe", runtime, PATH_MAX);
+              if (i != -1) {
+                  runtime[i] = '\0';
+                  execve(runtime, argv, envp);
+              }
+          }
+          /* Either changing the personality or execve() failed. Either
+           * way we might as well continue, and hope that the random
+           * memory maps are ok this time around.
+           */
+          fprintf(stderr, "WARNING: Couldn't re-execute SBCL with the proper personality flags (maybe /proc isn't mounted?). Trying to continue anyway.\n");
+       }
+    }
+#endif
 }