Move FD check to dl-sysdep.c

[Mark Kettenis <kettenis at wins dot uva dot nl>]

The following patch moves the call to __libc_check_standard_fds() from
elf/rtld.c:dl_main() to sysdeps/generic/dl-sysdep.c:_dl_sysdep_start(),
 just before the call to dl_main().  It would really help the Hurd if
this could be applied.  The presence of the
__libc_check_standard_fds() call in dl_main() prevents me from writing
an elegant solution to check the FDs on the Hurd.

The Hurd doesn't need to call __libc_check_standard_fds().  The
concept of file descriptors doesn't exist outside libc, and we'd
better check the file descriptors right when we build the file
descriptor table for the Hurd.  I'll check in a Hurd-specific
check_fds.c that takes care of that in the near future.

I think that sysdeps/generic/dl-sysdep.c conceptually is the right
place to put the call.  The need for __libc_check_standard_fds() is
related to the way file descriptors behave in a generic Unix system.

Mark

2000-07-09  Mark Kettenis  <kettenis@gnu.org>

	* elf/rtld.c (dl_main): Move call to __libc_check_standard_fds...
	* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): ... to here.

Index: elf/rtld.c
===================================================================
RCS file: /cvs/glibc/libc/elf/rtld.c,v
retrieving revision 1.173
diff -u -p -r1.173 rtld.c
--- elf/rtld.c	2000/06/10 03:58:55	1.173
+++ elf/rtld.c	2000/07/09 17:45:48
@@ -52,9 +52,6 @@ extern void *_dl_sysdep_read_whole_file 
 					 size_t *filesize_ptr,
 					 int mmap_prot);
 
-/* Protec SUID program against misuse of file descriptors.  */
-extern void __libc_check_standard_fds (void);
-
 /* Helper function to handle errors while resolving symbols.  */
 static void print_unresolved (int errcode, const char *objname,
 			      const char *errsting);
@@ -399,12 +396,6 @@ dl_main (const ElfW(Phdr) *phdr,
   hp_timing_t stop;
   hp_timing_t diff;
 #endif
-
-  /* First thing, if this is a SUID program we make sure that FDs 0,
-     1, and 2 are allocated.  If necessary we are doing it ourself.
-     If it is not possible we stop the program.  */
-  if (__builtin_expect (__libc_enable_secure, 0))
-    __libc_check_standard_fds ();
 
   /* Process the environment variable which control the behaviour.  */
   process_envvars (&mode, &_dl_lazy);
Index: sysdeps/generic/dl-sysdep.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/generic/dl-sysdep.c,v
retrieving revision 1.50
diff -u -p -r1.50 dl-sysdep.c
--- sysdeps/generic/dl-sysdep.c	2000/03/23 20:28:06	1.50
+++ sysdeps/generic/dl-sysdep.c	2000/07/09 17:45:48
@@ -45,6 +45,9 @@ extern fpu_control_t _dl_fpu_control;
 extern void _end;
 extern void ENTRY_POINT (void);
 
+/* Protect SUID program against misuse of file descriptors.  */
+extern void __libc_check_standard_fds (void);
+
 ElfW(Addr) _dl_base_addr;
 int __libc_enable_secure;
 int __libc_multiple_libcs = 0;	/* Defining this here avoids the inclusion
@@ -166,6 +169,12 @@ _dl_sysdep_start (void **start_argptr,
        break up that far.  When the user program examines its break, it
        will see this new value and not clobber our data.  */
     __sbrk (_dl_pagesize - ((&_end - (void *) 0) & (_dl_pagesize - 1)));
+
+  /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
+     allocated.  If necessary we are doing it ourself.  If it is not
+     possible we stop the program.  */
+  if (__builtin_expect (__libc_enable_secure, 0))
+    __libc_check_standard_fds ();
 
   (*dl_main) (phdr, phnum, &user_entry);
   return user_entry;