0.9.5.73:

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

diff --git a/src/runtime/linux-os.c b/src/runtime/linux-os.c
index 8fe0ca7..ce900a7 100644 (file)
--- a/src/runtime/linux-os.c
+++ b/src/runtime/linux-os.c
@@ -52,8 +52,10 @@
 #include "gencgc-internal.h"
 #endif
 
-#ifdef LISP_FEATURE_LINUX
-#include <sys/personality.h>
+#ifdef LISP_FEATURE_X86
+/* Prototype for personality(2). Done inline here since the header file
+ * for this isn't available on old versions of glibc. */
+int personality (unsigned long);
 #endif
 
 size_t os_vm_page_size;
@@ -96,16 +98,17 @@ int linux_sparc_siginfo_bug = 0;
 int linux_no_threads_p = 0;
 
 #ifdef LISP_FEATURE_SB_THREAD
-int isnptl (void)
+int
+isnptl (void)
 {
   size_t n = confstr (_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
-  if (n > 0)
-    {
+  if (n > 0) {
       char *buf = alloca (n);
       confstr (_CS_GNU_LIBPTHREAD_VERSION, buf, n);
-      if (strstr (buf, "NPTL"))
-        return 1;
-    }
+      if (strstr (buf, "NPTL")) {
+          return 1;
+      }
+  }
   return 0;
 }
 #endif
@@ -140,11 +143,11 @@ os_init(char *argv[], char *envp[])
 #ifdef LISP_FEATURE_SB_THREAD
     futex_wait(futex,-1);
     if(errno==ENOSYS) {
-       lose("This version of sbcl is compiled with threading support, but your kernel is too old to support this.\n\
+       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");
+       lose("This version of SBCL only works correctly with the NPTL threading library. Please use a newer glibc, use an older SBCL, or stop using LD_ASSUME_KERNEL");
     }
 #endif
     os_vm_page_size = getpagesize();
@@ -153,34 +156,47 @@ Please use a more recent kernel or a version of SBCL without threading support.\
      * 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).
+     *
+     * Since randomization is currently implemented only on x86 kernels,
+     * don't do this trick on other platforms.
      */
-#if defined(LISP_FEATURE_X86)
+#ifdef 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) != -1;
-              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");
-       }
+    {
+        int pers = personality(0xffffffffUL);
+        /* 0x40000 aka. ADDR_NO_RANDOMIZE */
+        if (!(pers & 0x40000)) {
+            int retval = personality(pers | 0x40000);
+            /* Allegedly some Linux kernels (the reported case was
+             * "hardened Linux 2.6.7") won't set the new personality,
+             * but nor will they return -1 for an error. So as a
+             * workaround query the new personality...
+             */
+            int newpers = personality(0xffffffffUL);
+            /* ... and don't re-execute if either the setting resulted
+             * in an error or if the value didn't change. Otherwise
+             * this might result in an infinite loop.
+             */
+            if (retval != -1 && newpers != pers) {
+                /* 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 in order to prevent 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
 }
@@ -207,11 +223,17 @@ os_validate(os_vm_address_t addr, os_vm_size_t len)
     }
 #endif
     actual = mmap(addr, len, OS_VM_PROT_ALL, flags, -1, 0);
-    if (actual == MAP_FAILED || (addr && (addr!=actual))) {
+    if (actual == MAP_FAILED) {
         perror("mmap");
         return 0;               /* caller should check this */
     }
 
+    if (addr && (addr!=actual)) {
+        fprintf(stderr, "mmap: wanted %lu bytes at %p, actually mapped at %p\n",
+                (unsigned long) len, addr, actual);
+        return 0;
+    }
+
 #ifdef LISP_FEATURE_ALPHA
 
     len=(len+(os_vm_page_size-1))&(~(os_vm_page_size-1));