Replace __libc_multiple_libcs with __libc_initial flag

Change sbrk to fail for !__libc_initial (in the generic
implementation).  As a result, sbrk is (relatively) safe to use
for the __libc_initial case (from the main libc).  It is therefore
no longer necessary to avoid using it in that case (or updating the
brk cache), and the __libc_initial flag does not need to be updated
as part of dlmopen or static dlopen.

As before, direct brk system calls on Linux may lead to memory
corruption.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

2 files changed, 6 insertions, 6 deletions

diff --git a/sysdeps/mach/hurd/dl-sysdep.c b/sysdeps/mach/hurd/dl-sysdep.c
index 370495710e..a5169d85e7 100644
--- a/sysdeps/mach/hurd/dl-sysdep.c
+++ b/sysdeps/mach/hurd/dl-sysdep.c
@@ -57,8 +57,6 @@ extern char **_environ;
 
 int __libc_enable_secure = 0;
 rtld_hidden_data_def (__libc_enable_secure)
-int __libc_multiple_libcs = 0;	/* Defining this here avoids the inclusion
-				   of init-first.  */
 /* This variable contains the lowest stack address ever used.  */
 void *__libc_stack_end = NULL;
 rtld_hidden_data_def(__libc_stack_end)
diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
index 1827479f86..cbbc12204a 100644
--- a/sysdeps/mach/hurd/i386/init-first.c
+++ b/sysdeps/mach/hurd/i386/init-first.c
@@ -30,6 +30,7 @@
 #include <ldsodefs.h>
 #include <fpu_control.h>
 #include <libc-diag.h>
+#include <libc-internal.h>
 
 extern void __mach_init (void);
 extern void __init_misc (int, char **, char **);
@@ -40,7 +41,6 @@ unsigned long int __hurd_threadvar_stack_mask;
 #ifndef SHARED
 int __libc_enable_secure;
 #endif
-int __libc_multiple_libcs attribute_hidden = 1;
 
 extern int __libc_argc attribute_hidden;
 extern char **__libc_argv attribute_hidden;
@@ -56,13 +56,12 @@ DEFINE_HOOK (_hurd_preinit_hook, (void));
 static void
 posixland_init (int argc, char **argv, char **envp)
 {
-  __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
-
   /* Now we have relocations etc. we can start signals etc.  */
   _hurd_libc_proc_init (argv);
 
+#ifdef SHARED
   /* Make sure we don't initialize twice.  */
-  if (!__libc_multiple_libcs)
+  if (__libc_initial)
     {
       /* Set the FPU control word to the proper default value.  */
       __setfpucw (__fpu_control);
@@ -72,6 +71,9 @@ posixland_init (int argc, char **argv, char **envp)
       /* Initialize data structures so the additional libc can do RPCs.  */
       __mach_init ();
     }
+#else /* !SHARED */
+  __setfpucw (__fpu_control);
+#endif
 
   /* Save the command-line arguments.  */
   __libc_argc = argc;