diff mbox series

[hurd,commited] hurd: keep only required PLTs in ld.so

Message ID 20201111013649.173478-1-samuel.thibault@ens-lyon.org
State Committed, archived
Headers show
Series [hurd,commited] hurd: keep only required PLTs in ld.so | expand

Commit Message

Samuel Thibault Nov. 11, 2020, 1:36 a.m. UTC
We need NO_RTLD_HIDDEN because of the need for PLT calls in ld.so.
See Roland's comment in
https://sourceware.org/bugzilla/show_bug.cgi?id=15605
"in the Hurd it's crucial that calls like __mmap be the libc ones
instead of the rtld-local ones after the bootstrap phase, when the
dynamic linker is being used for dlopen and the like."

We used to just avoid all hidden use in the rtld ; this commit switches to
keeping only those that should use PLT calls, i.e. essentially those defined in
sysdeps/mach/hurd/dl-sysdep.c:

__assert_fail
__assert_perror_fail
__*stat64
_exit

This fixes a few startup issues, notably the call to __tunable_get_val that is
made before PLTs are set up.
---
 elf/dl-minimal.c                     |  4 ++++
 include/dirent.h                     |  2 +-
 include/libc-internal.h              |  2 +-
 include/libc-symbols.h               |  2 +-
 include/setjmp.h                     |  2 +-
 include/signal.h                     |  2 +-
 include/stdlib.h                     |  2 +-
 include/string.h                     |  2 +-
 include/sys/utsname.h                |  2 +-
 include/unistd.h                     |  2 ++
 sysdeps/generic/_itoa.h              |  2 +-
 sysdeps/i386/dl-tlsdesc.S            |  4 ----
 sysdeps/mach/hurd/_exit.c            |  2 ++
 sysdeps/mach/hurd/dl-sysdep.c        |  4 ++--
 sysdeps/mach/hurd/i386/ld.abilist    |  1 -
 sysdeps/mach/hurd/i386/localplt.data | 15 +--------------
 sysdeps/x86_64/dl-tlsdesc.S          |  4 ----
 17 files changed, 20 insertions(+), 34 deletions(-)
diff mbox series

Patch

diff --git a/elf/dl-minimal.c b/elf/dl-minimal.c
index b37abfaff9..1168ac786e 100644
--- a/elf/dl-minimal.c
+++ b/elf/dl-minimal.c
@@ -292,7 +292,9 @@  Inconsistency detected by ld.so: %s: %u: %s%sAssertion `%s' failed!\n",
 		    assertion);
 
 }
+# ifndef NO_RTLD_HIDDEN
 rtld_hidden_weak (__assert_fail)
+# endif
 
 void weak_function
 __assert_perror_fail (int errnum,
@@ -306,7 +308,9 @@  Inconsistency detected by ld.so: %s: %u: %s%sUnexpected error: %s.\n",
 		    __strerror_r (errnum, errbuf, sizeof errbuf));
 
 }
+# ifndef NO_RTLD_HIDDEN
 rtld_hidden_weak (__assert_perror_fail)
+# endif
 #endif
 
 #undef _itoa
diff --git a/include/dirent.h b/include/dirent.h
index 8325a19e5f..f1d7e8359c 100644
--- a/include/dirent.h
+++ b/include/dirent.h
@@ -81,7 +81,7 @@  extern int __scandir64_tail (DIR *dp,
 libc_hidden_proto (__rewinddir)
 extern __typeof (scandirat) __scandirat;
 
-#  if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+#  if IS_IN (rtld)
 extern __typeof (__rewinddir) __rewinddir attribute_hidden;
 #  endif
 # endif
diff --git a/include/libc-internal.h b/include/libc-internal.h
index 729db7918e..915613c030 100644
--- a/include/libc-internal.h
+++ b/include/libc-internal.h
@@ -43,7 +43,7 @@  extern void __libc_thread_freeres (void);
 /* Define and initialize `__progname' et. al.  */
 extern void __init_misc (int, char **, char **) attribute_hidden;
 
-# if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+# if IS_IN (rtld)
 extern __typeof (__profile_frequency) __profile_frequency attribute_hidden;
 # endif
 
diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 60153bb50d..b8103b98bb 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -643,7 +643,7 @@  for linking")
 # define libc_hidden_data_ver(local, name)
 #endif
 
-#if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+#if IS_IN (rtld)
 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 # define rtld_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
 # define rtld_hidden_def(name) hidden_def (name)
diff --git a/include/setjmp.h b/include/setjmp.h
index e13017edd2..0a8e4d2eaf 100644
--- a/include/setjmp.h
+++ b/include/setjmp.h
@@ -27,7 +27,7 @@  extern void __libc_longjmp (sigjmp_buf env, int val)
 libc_hidden_proto (_setjmp)
 libc_hidden_proto (__sigsetjmp)
 
-# if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+# if IS_IN (rtld)
 extern __typeof (__sigsetjmp) __sigsetjmp attribute_hidden;
 # endif
 
diff --git a/include/signal.h b/include/signal.h
index 544d701bce..2a278697c1 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -67,7 +67,7 @@  extern int __xpg_sigpause (int sig);
 /* Allocate real-time signal with highest/lowest available priority.  */
 extern int __libc_allocate_rtsig (int __high);
 
-#  if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+#  if IS_IN (rtld)
 extern __typeof (__sigaction) __sigaction attribute_hidden;
 extern __typeof (__libc_sigaction) __libc_sigaction attribute_hidden;
 #  endif
diff --git a/include/stdlib.h b/include/stdlib.h
index ffcefd7b85..cdbdbf310d 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -310,7 +310,7 @@  struct abort_msg_s
 extern struct abort_msg_s *__abort_msg;
 libc_hidden_proto (__abort_msg)
 
-# if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+# if IS_IN (rtld)
 extern __typeof (unsetenv) unsetenv attribute_hidden;
 extern __typeof (__strtoul_internal) __strtoul_internal attribute_hidden;
 # endif
diff --git a/include/string.h b/include/string.h
index f4ce138622..7d344d77d4 100644
--- a/include/string.h
+++ b/include/string.h
@@ -150,7 +150,7 @@  libc_hidden_builtin_proto (strspn)
 libc_hidden_builtin_proto (strstr)
 libc_hidden_builtin_proto (ffs)
 
-#if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+#if IS_IN (rtld)
 extern __typeof (__stpcpy) __stpcpy attribute_hidden;
 extern __typeof (__strdup) __strdup attribute_hidden;
 extern __typeof (__strerror_r) __strerror_r attribute_hidden;
diff --git a/include/sys/utsname.h b/include/sys/utsname.h
index 9ed5fa2565..14f4247dd4 100644
--- a/include/sys/utsname.h
+++ b/include/sys/utsname.h
@@ -7,7 +7,7 @@  extern int __uname (struct utsname *__name);
 libc_hidden_proto (uname)
 libc_hidden_proto (__uname)
 
-# if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
+# if IS_IN (rtld)
 extern __typeof (__uname) __uname attribute_hidden;
 # endif
 #endif
diff --git a/include/unistd.h b/include/unistd.h
index f48da2c7a3..54becbc9eb 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -4,7 +4,9 @@ 
 # ifndef _ISOMAC
 
 libc_hidden_proto (_exit, __noreturn__)
+#  ifndef NO_RTLD_HIDDEN
 rtld_hidden_proto (_exit, __noreturn__)
+#  endif
 libc_hidden_proto (alarm)
 extern size_t __confstr (int name, char *buf, size_t len);
 libc_hidden_proto (__confstr)
diff --git a/sysdeps/generic/_itoa.h b/sysdeps/generic/_itoa.h
index 790f88a6d5..ef4de3af1b 100644
--- a/sysdeps/generic/_itoa.h
+++ b/sysdeps/generic/_itoa.h
@@ -46,7 +46,7 @@  extern char *_itoa (unsigned long long int value, char *buflim,
 
 extern const char _itoa_upper_digits[];
 extern const char _itoa_lower_digits[];
-#if IS_IN (libc) || (IS_IN (rtld) && !defined NO_RTLD_HIDDEN)
+#if IS_IN (libc) || IS_IN (rtld)
 hidden_proto (_itoa_upper_digits)
 hidden_proto (_itoa_lower_digits)
 #endif
diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S
index 32383e3bad..6d57739515 100644
--- a/sysdeps/i386/dl-tlsdesc.S
+++ b/sysdeps/i386/dl-tlsdesc.S
@@ -129,11 +129,7 @@  _dl_tlsdesc_dynamic:
 	.p2align 4,,7
 .Lslow:
 	cfi_adjust_cfa_offset (28)
-#ifdef NO_RTLD_HIDDEN
-	call	JUMPTARGET (___tls_get_addr)
-#else
 	call	HIDDEN_JUMPTARGET (___tls_get_addr)
-#endif
 	jmp	.Lret
 	cfi_endproc
 	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
diff --git a/sysdeps/mach/hurd/_exit.c b/sysdeps/mach/hurd/_exit.c
index 46db06db63..f04c5d2acf 100644
--- a/sysdeps/mach/hurd/_exit.c
+++ b/sysdeps/mach/hurd/_exit.c
@@ -51,5 +51,7 @@  _exit (int status)
   _hurd_exit (W_EXITCODE (status, 0));
 }
 libc_hidden_def (_exit)
+#ifndef NO_RTLD_HIDDEN
 rtld_hidden_def (_exit)
+#endif
 weak_alias (_exit, _Exit)
diff --git a/sysdeps/mach/hurd/dl-sysdep.c b/sysdeps/mach/hurd/dl-sysdep.c
index 5c0bb3124d..6b32d41c76 100644
--- a/sysdeps/mach/hurd/dl-sysdep.c
+++ b/sysdeps/mach/hurd/dl-sysdep.c
@@ -641,7 +641,8 @@  __sbrk (intptr_t increment)
   return (void *) addr;
 }
 
-check_no_hidden(__strtoul_internal);
+/* This is only used by hurdlookup for the /dev/fd/nnn magic.
+ * We avoid pulling the whole libc implementation, and we can keep this hidden.  */
 unsigned long int weak_function
 __strtoul_internal (const char *nptr, char **endptr, int base, int group)
 {
@@ -698,7 +699,6 @@  abort (void)
 /* We need this alias to satisfy references from libc_pic.a objects
    that were affected by the libc_hidden_proto declaration for abort.  */
 strong_alias (abort, __GI_abort)
-strong_alias (abort, __GI___chk_fail)
 strong_alias (abort, __GI___fortify_fail)
 strong_alias (abort, __GI___assert_fail)
 strong_alias (abort, __GI___assert_perror_fail)
diff --git a/sysdeps/mach/hurd/i386/ld.abilist b/sysdeps/mach/hurd/i386/ld.abilist
index 2e9bf2811f..0eaea9f66d 100644
--- a/sysdeps/mach/hurd/i386/ld.abilist
+++ b/sysdeps/mach/hurd/i386/ld.abilist
@@ -9,7 +9,6 @@  GLIBC_2.2.6 __open64 F
 GLIBC_2.2.6 __pread64 F
 GLIBC_2.2.6 __read F
 GLIBC_2.2.6 __sbrk F
-GLIBC_2.2.6 __strtoul_internal F
 GLIBC_2.2.6 __write F
 GLIBC_2.2.6 __writev F
 GLIBC_2.2.6 __xstat64 F
diff --git a/sysdeps/mach/hurd/i386/localplt.data b/sysdeps/mach/hurd/i386/localplt.data
index b199e14e7f..abd8f31fac 100644
--- a/sysdeps/mach/hurd/i386/localplt.data
+++ b/sysdeps/mach/hurd/i386/localplt.data
@@ -37,24 +37,11 @@  ld.so: __access_noerrno
 ld.so: __getpid
 ld.so: __getcwd
 ld.so: __sbrk
-ld.so: __strtoul_internal
-#ld.so: _exit
+ld.so: _exit ?
 ld.so: abort
 ld.so: _hurd_intr_rpc_mach_msg
 ld.so: __errno_location
-# rtld_hidden is currently disabled to avoid having to special-case the
-# functions above which do need a PLT.  These are thus currently expected.
-ld.so: _dl_allocate_tls
-ld.so: _dl_allocate_tls_init
-ld.so: _dl_exception_create
-ld.so: _dl_exception_create_format
-ld.so: _dl_exception_free
-ld.so: _dl_fatal_printf
-ld.so: _dl_find_dso_for_object
 ld.so: _dl_init_first
-ld.so: _dl_mcount
-ld.so: ___tls_get_addr
-ld.so: __tunable_get_val
 #
 # These should ideally be avoided, but is currently difficult
 libc.so: siglongjmp ?
diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
index 512a704fac..2535c88946 100644
--- a/sysdeps/x86_64/dl-tlsdesc.S
+++ b/sysdeps/x86_64/dl-tlsdesc.S
@@ -131,11 +131,7 @@  _dl_tlsdesc_dynamic:
 	movq	%r10, 40(%rsp)
 	movq	%r11, 48(%rsp)
 	/* %rdi already points to the tlsinfo data structure.  */
-#ifdef NO_RTLD_HIDDEN
-	call	JUMPTARGET (__tls_get_addr)
-#else
 	call	HIDDEN_JUMPTARGET (__tls_get_addr)
-#endif
 	movq	8(%rsp), %rdx
 	movq	16(%rsp), %rcx
 	movq	24(%rsp), %r8